Filtering Airborne Lidar Data by Modified White Top-Hat Transform with Directional Edge Constraints
|
|
- Antonia Shaw
- 5 years ago
- Views:
Transcription
1 Filtering Airborne Lidar Data by Modified White Top-Hat Transform with Directional Edge Constraints Yong Li, Bin Yong, Huayi Wu, Ru An, Hanwei Xu, Jia Xu, and Qisheng He Abstract A novel algorithm that employs modified white top-hat (MWTH) transform with directional edge constraints is proposed in this study to automatically extract ground points from airborne light detection and ranging (lidar) data. MWTH transform can effectively distinguish above-ground objects that are smaller than the window size and higher than the height difference threshold. Directional edge constraints significantly decrease omission errors from protruding ground features. Incorporating MWTH transform and directional edge constraints enables the simultaneous consideration of the size, height, and edge characteristics of lidar data for judging above-ground objects. Experimental results verify that the proposed algorithm exhibits promising performance and high accuracy in various complicated landscapes, even in areas with dramatic changes in elevation. The proposed algorithm has minimal omission and commission error oscillation for different test sites, thereby demonstrating its stability and reliability in a wide range of applications. Introduction Airborne light detection and ranging (lidar) technology has become a powerful and popular tool for rapid spatial data acquisition with acceptable spatial accuracy and large density (Filin and Pfeifer, 2006; Meng et al., 2009b; Shan and Sampath, 2005). Lidar can obtain three-dimensional (3D) coordinates of the surface of the Earth in a more convenient manner compared with traditional photogrammetric and field surveying methods. Lidar is also unaffected by external light conditions and requires few ground control points. These incomparable merits of lidar have attracted considerable attention from specialists and scholars in diverse fields. Although lidar systems have been widely utilized in various practical applications such as topographic surveying and environmental planning (Hill et al., 2000; Stoker et al., 2006; White and Wang, 2003), effectively processing raw data and accurately extracting useful information still remain a major challenge in complex situations, especially for areas with steep slopes or rough surfaces (Chen, 2007). Yong Li and Bin Yong are with the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing , China (liyong@hhu.edu.cn; yongbin_hhu@126.com). Huayi Wu is with the State Key Laboratory of Information Engineering in Surveying, Mapping, and Remote Sensing, Wuhan University, Wuhan , China. Ru An, Hanwei Xu, Jia Xu, and Qisheng He are with the School of Earth Sciences and Engineering, Hohai University, Nanjing , China. Raw lidar data sets contain both ground and non-ground points such as buildings, vegetation, vehicles, and electrical wires. The first important step in digital terrain model generation and object extraction is to separate obtained point clouds into ground and non-ground points. This process is called filtering (Vosselman, 2000; Zhang et al., 2003). Manual classification and final quality control account for approximately 60 percent to 80 percent of total lidar data processing time because no efficient algorithms are available for filtering (Flood, 2001; Sithole and Vosselman, 2003). Considering the presence of complex and changeable landscapes in a surveyed field, lidar data filtering is difficult to automate in computers, especially for large areas with varying terrain characteristics (Bartels and Wei, 2010; Silvan-Cardenas and Wang, 2006; Sithole and Vosselman, 2004; Zhang and Whitman, 2005). Various approaches have been developed to filter lidar point clouds in recent decades (Bartels and Wei, 2010; Silvan-Cardenas and Wang, 2006; Sithole and Vosselman, 2004; Zhang and Whitman, 2005). These methods are mostly based on the assumption that most terrain surfaces have gradual elevation changes, whereas above-ground objects possess abrupt elevation changes compared with nearby ground (Bretar and Chehata, 2010). Moreover, the sizes of objects are within a limited range. Larger above-ground objects usually have more evident height differences, so a larger height threshold is necessary to filter the larger objects. The slope-based approach inspects slopes or height differences among nearby points. A predefined threshold is utilized for filtering based on the assumption that gradients between ground and nonground points are distinctively different (Shan and Sampath, 2005; Sithole, 2001; Vosselman, 2000; Wang and Tseng, 2010; Wang and Shan, 2009). The morphological approach involves a series of morphological operations, such as openings and closings, to separate objects and backgrounds (Chen et al., 2007; Li and Wu, 2009; Petzold et al., 1999; Wu et al., 2010; Zhang et al., 2003). The surface interpolation approach and triangular irregular network densification approach iteratively approximate the ground under strong angle and distance constraints (Axelsson, 1999 and 2000; Kraus and Pfeifer, 1998; Lee and Younan, 2003; Pfeifer et al., 2001; Sohn and Dowman, 2002). The directional scanning approach involves the calculation of slopes and elevation differences along a one-dimensional (1D) scan line in a specified direction and identifies ground points based on information along the scan line (Meng Photogrammetric Engineering & Remote Sensing Vol. 80, No. 2, February 2014, pp /14/ American Society for Photogrammetry and Remote Sensing doi: /PERS PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING February
2 et al., 2009a and 2009b; Shan and Sampath, 2005; Sithole, 2001; Sithole and Vosselman, 2005). Current approaches are generally suitable for flat terrains. However, obtaining reliable results for complex landscapes remain difficult, particularly in steeply sloping terrains (Meng et al., 2009b; Mongus and Žalik, 2012). Most filtering algorithms are adapted to various circumstances by tuning the adopted parameters. The proposed algorithm aims to remove above-ground objects as well as preserve terrain features by incorporating modified white top-hat (MWTH) transform and directional edge constraints. The morphological approach is a commonly used approach among existing approaches (Silvan-Cardenas and Wang, 2006). Several researchers have developed a number of filters based on mathematical morphology, which can remove object points efficiently (Arefi and Hahn, 2005; Chen et al., 2007; Kobler et al., 2007; Zhang et al., 2003). Adapting the size of the window used is necessary to ensure that certain terrain points belong to the window, thereby eliminating non-ground objects of different sizes. Protruding terrain features are flattened when a large window for morphological operators is utilized to remove large objects, such as buildings. Several researchers have gradually expanded window size to remove non-ground objects of different sizes and avoid mislabeling of ground points (Vosselman, 2000; Zhang et al., 2003; Zhang and Whitman, 2005). Zhang et al. (2003) identified non-ground points by comparing elevation differences from a morphological opening with a predefined threshold, which was actually MWTH transform (Bai et al., 2010). However, differentiation between ground and objects, particularly when a large window is used on abrupt surfaces, is an unresolved issue because of the similar characteristics of ground and non-ground objects (Bartels and Wei, 2010; Liu, 2008; Meng et al., 2009b; Mongus and Žalik, 2012; Sithole and Vosselman, 2004). A novel algorithm that incorporates MWTH transform with directional edge constraints is proposed in this study for the efficient filtering of lidar data. Two main steps are employed in differentiating non-ground points from terrain points at each time of iteration. MWTH transform is first utilized to extract potential above-ground objects. The objects are then determined by directional edge constraints imposed on potential objects. The size, height, and edge characteristics of objects are simultaneously considered in judging above-ground points. The experimental test results are compared with the results of other publicized filtering algorithms tested by the International Society for Photogrammetry and Remote Sensing (ISPRS) Commission III/WG3 (Sithole and Vosselman, 2003) to evaluate the performance of the proposed algorithm. The results reveal the robustness and practicality of the proposed method. This paper is organized as follows. A detailed description of the method is provided in the next section, followed by a description and discussion of Experiments. Summarizing remarks and conclusions finalize the paper. Methodology The proposed algorithm identifies above-ground objects based on the size, height, and edge characteristics of point clouds caused by various objects (e.g., buildings, vegetation, or vehicles). First, a grid index structure is created for efficient point cloud organization. Morphological gradients are calculated to analyze the elevation changes in the lidar point cloud. Low outliers are eliminated to prevent them from affecting subsequent gradient analysis. Second, small and low objects near the ground surface are removed by MWTH transform and directional edge constraints with a small window size and height difference threshold. Finally, MWTH transform and directional edge constraints are iterated with increased window size and height difference threshold to eliminate large objects. This step is repeated until the utilized window becomes larger Figure 1. Flowchart of the complete methodology. than the largest object. The flowchart of the proposed algorithm is shown in Figure 1. This section is divided into three subsections to explain the methodology. Three preprocessing steps, namely, grid index creation, morphological gradient calculation, and outlier removal, are presented in the first subsection. The subsequent subsections respectively illustrate MWTH transform and directional edge constraints. Preprocessing Three preprocessing steps must be performed prior to filtering above-ground objects in raw lidar point clouds. The steps are grid index creation, morphological gradient calculation, and outlier removal. A lidar strip generally contains several million of 3D laser points, which require efficient point cloud organization. Interpolating irregularly distributed points into a regular grid is favorable for the use of digital image processing techniques (Chen et al., 2007; Lloyd and Atkinson, 2006; Meng et al., 2009b; Mongus and Žalik, 2012; Zhang et al., 2003). However, interpolation methods cause information loss and artificial error (Liu, 2008; Shan and Sampath, 2005). Directly processing raw irregular point clouds (Elmqvist, 2002; Shan and Sampath, 2005; Sithole and Vosselman, 2005; Zhang and Whitman, 2005) can prevent errors introduced by interpolation but requires complex neighbor search methods (Meng et al., 2009b). In this study, a grid index structure that maximizes the simplicity of a regular grid and maintains the accuracy of raw data without interpolation is utilized to manage irregular point clouds. The input point cloud is arranged into a predefined index grid G with equal-sized cells. Each grid cell stores an array of lidar points. Empty cells are ignored during the remaining steps of the algorithm. During spatial searching and processing of each lidar point, the relevant cell is first determined. The contained points are then selected for calculation. The cell size that can accurately represent neighborhood relationships among lidar points depends on the density of the point clouds. The average point spacing of raw point clouds is a relatively suitable reference for grid-cell size. For instance, if point spacing ranges from 1 m to 2 m, then grid-cell size is set to 2 m 2 m. 134 February 2014 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
3 The next preprocessing step is to calculate the morphological gradients of point clouds to analyze the elevation changes. Mathematical morphology, which was developed based on geometry and set theory, is a powerful tool for spatial feature extraction and analysis (Soille, 2003). Erosion and dilation are two fundamental morphological operations that work with a roving two-dimensional window superimposed upon the original data set. The window, also referred to as the structuring element (SE), specifies the reference neighborhood of a considered point. The elevation of point l(x, y) of set f after being eroded by SE B is denoted as [f B ( f )](x, y) and defined as follows: [f B ( f )](x, y) = min{f(x+i, y+j) i,j [-w, w]; (x+i), (y+j) D f }, (1) where D f is the domain of f, and the size of SE B is (2w + 1) (2w + 1). Erosion presents the lowest elevation within the neighborhood defined by SE B, whereas dilation presents the highest elevation of the highest point within the neighborhood defined by SE B. The elevation of point l(x, y) of set f after being dilated by SE B is denoted as [d B ( f )](x, y) and defined as follows: [d B ( f )](x, y) = max{f(x+i, y+j) i,j [-w, w]; (x+i), (y+j) D f }. (2) The gradients of each point indicate the elevation changes in the close neighborhood of that point. The elevation changes of non-ground objects are different from the elevation changes of ground points; thus, gradients can be utilized to analyze nonground lidar points. The gradients can be expressed numerically by morphological operations in several ways (Soille, 2003). Two types of morphological gradients are employed in the proposed algorithm, namely, internal and external gradients. Internal gradients are operators that represent the extent of descent of a point elevation in a neighborhood determined by SE as shown in Figure 2b. The internal gradient of the considered point l is defined as the difference between the original and eroded values by elementary SE B (3 3 square), which is denoted by t : t B = f f B. (3) Similarly, external gradients represent the extent of the ascent of a point elevation in a neighborhood determined by SE, as shown in Figure 2c. External gradient t + is defined as the difference between the dilated and original values: t + B = d B f. (4) The last preprocessing step involves the removal of low outliers in the point clouds. Low outliers are commonly caused by laser returns that are reflected several times or by the malfunction of a laser rangefinder (Sithole and Vosselman, 2004). The distinctive characteristic of low outliers is that these points are unrealistically lower than the surrounding points, thereby resulting in inconsistencies in gradient analysis for filtering. Therefore, low outliers must be eliminated beforehand. A lidar point is identified as belonging to a low outlier based on two conditions: (a) external gradient t + is larger than the predefined threshold, which means that the point is located extremely low in a local region, and (b) the number of neighboring points close to the point is small, indicating that the point is rare and scattered. The threshold of t + and the number of close points in a 3 3 neighborhood of a low outlier, which are set by trial and error, are 5 m and two points, respectively, for the data sets tested in this study. MWTH Transform for Filtering Lidar Data Above-ground objects possess abrupt elevation changes compared with the surrounding ground surface. This fact is the basis for filtering algorithms, as presented in the Introduction Section. Terrains are often uneven in reality; thus, global threshold techniques are generally unsatisfactory. Morphological top-hat transform can mitigate terrain relief and probe local height contrast. White top-hat (WTH) transform is widely utilized to extract image components that are brighter than the background in gray-scale image processing. This technique can be utilized to extract objects higher than the surrounding ground in lidar filtering. WTH is the difference between original set f and its opening c B ( f ) that is defined as erosion followed by dilation (Soille, 2003): c B ( f ) = d B [f B ( f )]. (5) WTH transformation of set f by SE B as denoted by WTH B ( f ) is defined as: WTH B ( f ) = f c B ( f ). (6) As illustrated in Figure 3, the WTH returns a subset of objects smaller than SE and higher than the surrounding regions. WTH with a flat isotropic SE functions as a high-pass filter (Soille, 2003). Thus, WTH with a specified neighborhood window size can be utilized to detect potential proportionally sized objects in point clouds. Figure 2. Example of morphological gradients of 1d lidar points: (a) objects A and B in original lidar data and the employed SE, (b) internal gradients, and (c) external gradients. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING February
4 Figure 3. wth of 1d lidar points: (a) original data set f and its opening c B ( f ), and (b) outputs of WTH( f ) = f c B ( f ). Figure 4. Comparison of edge characteristics between protruding terrain and objects: (a) 1d lidar points, and (b) outputs of mwth. Aside from abrupt elevation changes in objects, moderate relief also commonly occurs on terrains in actual landscapes. Morphological opening changes most of the elevation values of the original data set, and all the changed regions produce outputs in the resulting set of WTH. Thus, the resulting set of WTH has numerous ground regions except for object regions. Potential object regions are not necessarily non-zero regions but regions with significant elevation changes in the outputs of WTH. Thus, a height difference threshold can be imported into WTH to differentiate between potential object region and slow varied ground based on the elevation changes of these regions. MWTH with a height difference threshold can be expressed as follows (Bai et al., 2010): MWTH B (x, y) = max(f(x, y) c B (x, y), t) t, (7) where t is the height difference threshold. By accurately specifying t, MWTH can be employed to mark high regions with elevation change larger than t, which suppresses most terrain relief (e.g., Part B in Figure 4). During the processing of lidar data by MWTH, the morphology of the objects to be extracted from a raw point cloud depends on two parameters, namely, height difference threshold t and utilized SE size of (2w + 1) (2w + 1). Above-ground objects are categorized into two groups. The first group includes small and low objects near the ground surface such as isolated vegetation points, shrubs, road signs, and fences. This group of objects can be removed by employing a special small w and t, which are set as follows: w = 1, t = pointspacing/3, (8) where pointspacing refers to the average point spacing utilized to create the grid index in the Preprocessing Subsection. The second group of objects contains large objects such as buildings, which have to be removed progressively by iteratively increasing w and t. In the iterative filtering process, w and t are determined by the following equation: w = ½i a/pointspacing½, t = i, (9) where i [1, 2,, n] and a is a coefficient orienting the filter toward removing objects or preserving terrain features; a is set as 3 for the data set tested in this study. Directional Edge Constraints The primary challenge for morphological filters is to avoid the removal of protruding terrain features when the SE must be large for removing large objects such as buildings (Chen et al., 2007). Although terrain features can be maintained to a certain extent by setting a height difference threshold in top-hat transform, omission errors may still occur when the utilized window covers a large-scale terrain with abrupt elevation changes (see Figure 4). Component A of the protruding terrain is eliminated after employing a height difference threshold in MWTH (see Figure 4b). The internal gradients of the edges of the continuous regions can be utilized to determine if the extracted top hats belong to the ground or to an object. The examples in Figure 4 indicate that the internal gradients of edge points a1 and a2 of the protruding ground component, which are extracted by MWTH, are distinctly smaller than the internal gradients of edge points b1 and b2 of object C. Discontinuity occurs only on one side although terrain discontinuities (e.g., cliffs) may have dramatically large internal gradients similar to those of objects. Therefore, internal gradients along a scan line in a specified direction can be employed to determine whether components extracted by MWTH belong to above-ground objects. 136 February 2014 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
5 Figure 5. Edge constraints imposed on the outputs of mwth considering the end points of continuous point sequences along scan lines: (a) digital surface model generated from raw lidar data, and (b) directional scanning after mwth. For top hats extracted by MWTH, directional edge constraints are executed along scan lines whose directions are from left to right on every row of the index grid and from bottom to top on every column of the index grid as illustrated in Figure 5. The sequences of continuous points on every scan line are detected and judged one by one. A point sequence is judged as an object depending on the characteristics of the two end points. A sequence of points is considered as belonging to an object when the two end points of the sequence meet one of the following conditions: (a) the internal gradients are higher than the predefined threshold, (b) the end points lie on the boundary of the data set (i.e., large objects partially contained in the data set), and (c) the neighboring grid cell on the external side is empty. Results The practical performance of the proposed algorithm is assessed by the standard data set provided by the ISPRS Commission III/WG3 on its website ( filtertest/). The data set was acquired in the Vaihingen/Enz test field and Stuttgart City center with an Optech ALTM scanner. A total of 15 reference samples were selected from seven study sites and compiled by manual processing to provide ground-truth data to be utilized in testing the accuracy of filters (Sithole and Vosselman, 2004). Table 1 shows that the test data typically contain special features that challenge automatic filtering, including rugged terrain, complex buildings, dense vegetation, data gaps, bridges, vehicles, etc. (Sithole and Vosselman, 2003). Point spacing is between 1.0 m and 1.5 m for urban areas (Samples 11 to 42 in Plate 1) and between 2.0 m and 3.5 m for rural areas (Samples 51 to 71 in Plate 2). The threshold values of the data are made identical except for the grid-cell size of the grid index structure mentioned in Preprocessing Subsection to test the robustness of fixed parameters in the proposed algorithm. Grid-cell size depends on the density of the point cloud, thus preventing grid cells from containing too many points or none at all. In this study, the grid-cell size is set to be slightly higher than the average point spacing, namely, 1.5 m 1.5 m for urban data sets and 3.5 m 3.5 m for rural data sets. The proposed algorithm has promising and competitive results compared with other popular filtering algorithms tested by the ISPRS (Sithole and Vosselman, 2003; Sithole and Vosselman, 2004). Based on the average overall accuracy of all sample data (Figure 6), four algorithms are found to have average overall accuracy values larger than 90 percent. Axelsson (1999 and 2000) and Sohn and Dowman (2002) both analyzed ground surface through progressive densification of sparse TIN based on certain triangle and distance criteria. Pfeifer et al. (2001) adopted a hierarchical interpolation method to derive ground points. More comprehensive comparisons of the four algorithms are performed based on Type I and Type II errors (see Figures 7, 8, 9, and 10). Type I error refers to the percentage of ground points rejected as objects in all ground points, whereas Type II error is the percentage of object points accepted as ground in all object points. Figures 7, 8, and 9 show that the proposed method can simultaneously control the two error types at a relatively low level and can maintain balance between the two types of errors. Among the considered algorithms, the proposed algorithm has the smallest standard deviation for Type I and II errors (Figure 10), which means that the algorithm has the most stable response to diverse landscapes. This advantage is favorable to quality control of generating Location Site Sample Features Urban Rural Table 1. Features Of The Data Set Provided By Isprs For Algorithm Testing Steep slopes, mixture of vegetation and buildings on hillside, buildings on hillside, data gaps Large buildings, irregularly shaped buildings, road with bridge and small tunnel, data gaps Densely packed buildings with vegetation between them, building with eccentric roof, open space with mixture of low and high features, data gaps Railway station with trains (low density of terrain points), data gaps Steep slopes with vegetation, quarry, vegetation on river bank, data gaps 6 61 Large buildings, road with embankment, data gaps 7 71 Bridge, underpass, road with embankments, data gaps PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING February
6 Figure 6. Average overall accuracy of the considered algorithms. Figure 7. Type I error of the different algorithms for all samples. Figure 8. Type II error of the different algorithms for all samples. practical digital elevation model (DEM) for large-scale areas. Plates 1 and 2 present the error distributions of the proposed algorithm for each sample. Given that the proposed algorithm filters objects based on MWTH transform and subsequently suppresses omissions of terrain features through directional edge constraints, the algorithm can preserve the shapes of various terrain features with dramatic elevation changes (see Samples 22, 23, 51, 52, and 53 in Plates 1 and 2). For filtering steep slopes in dramatically rugged areas, various vegetation and complicated buildings are effectively extracted, and the main terrain features are well preserved (see Samples 11, 24, 51, 52, and 53 in Plates 1 and 2). Small objects (e.g., vehicles and shrubs) are distinguished by the small window size (see Sample 12 in Plate 1). Attached objects appear to be connected to the ground on one side while exhibiting a clear distance from the ground on the other side. Attached objects such as bridges are successfully removed (see Samples 21, 22, and 71 in Plates 1 and 2). The morphological operations only consider neighbors within the specified window, thus data holes caused by water absorption or swath gaps have no effect on filtering (Samples 41, 51, 52, and 61 in Plates 1 and 2). A few low and large objects exceed the assumption defined by Equation 9, which results in commission errors such as those in Samples 11 and 42 in Plate 1. The proposed algorithm requires seconds to conduct filtering on Site 1 which contains 683,204 lidar points with an Intel Core i GHz processor, 2 GB RAM, and Microsoft Visual C MWTH and directional edge constraints are the main filtering steps utilized in the proposed algorithm as previously mentioned. MWTH can effectively remove above-ground objects smaller than the utilized neighborhood window size as shown in Plate 3b. However, several protruding terrain features may be eliminated in rugged areas (e.g., Sample 53 ). Plate 3d indicates that a rejected ground portion, which has discontinuities on one side and a steep slope on the other, exists in the center of Sample 53 in Plate 2. Plates 3b and 3e show that the protruding ground is filtered because the extent of ground protrusion exceeds the height difference threshold of MWTH. The retrieved protruding ground features (see Plates 3c and 3f) demonstrate the effectiveness of the directional edge constraints imposed on top hats obtained using MWTH. Figure 9. Mean of Type I and II errors for all samples. Figure 10. Standard deviation of Type I and II errors for all samples. Conclusions Filtering lidar point clouds is a significant research challenge because of varying terrain and complex objects. A novel algorithm that incorporates MWTH transform with directional edge constraints is proposed for lidar data filtering in this study. MWTH can effectively distinguish above-ground objects smaller than the utilized window size and higher than the height difference threshold. Directional edge constraints can significantly reduce the occurrence of omission errors from protruding ground features. Incorporating MWTH and directional edge constraints enables the algorithm to simultaneously consider the size, height, and edge characteristics of point clouds for judging above-ground points. Experimental results based on the standard test data of ISPRS confirm the effectiveness and practicality of the proposed algorithm. The competitive performance is achieved in comparison with the other typical filtering algorithms tested by ISPRS. The size and shape of non-ground objects have no significant influence on the performance of the proposed algorithm. The proposed algorithm is robust to various complicated scenes, indicating that the algorithm is reliable and can be applied extensively, particularly in areas with dramatic elevation changes. The minimal standard deviations of omission and commission errors denote the stable response of the proposed algorithm 138 February 2014 PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
7 (c) (b) (a) (d) (f ) (e) (g) (h) (i) Plate 1. Error distribution for urban samples (11 to 42) displayed at a unique scale: (a) Sample 11, (b) Sample 12, (c) Sample 21, (d) Sample 22, (e) Sample 23, (f) Sample 31, (g) Sample 42, (h) Sample 24, and (i) Sample 41. to diverse landscapes, which is favorable to quality control of DEM products. This simple and efficient algorithm also has relatively fast processing speed which is helpful in surveying large-scale areas. However, the experimental results indicate that a few low and large objects may cause errors because the objects exceed the assumption defined by the empirical relation equation of window size and height difference threshold. The process of tuning parameters in a self-adaptive manner requires further investigation. PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING Acknowledgments This work was supported by the National Natural Science Foundation of China ( ; ; ; ; ), the 973 Program (2012CB719906) and the Fundamental Research Funds for the Central Universities (2011B06614). The authors thank three anonymous reviewers who helped to improve the earlier version of this paper. Fe b ruar y
8 (b) (a) (c) (d) (e) (f ) Plate 2. Error distribution for rural samples (51 to 71) displayed at a unique scale: (a) Sample 51, (b) Sample 52, (c) Sample 53, (d) Sample 54, (e) Sample 61, and (f) Sample 71. Plate 3. Processing point cloud of Sample 53: (a) digital surface model generated from raw data (the dotted line denotes profile position), (b) error distribution after mwth, (c) error distribution after edge constraints are imposed on mwth, (d) ground points along the profile in (a), (e) ground points along the profile in (b), and (f) ground points along the profile in (c). 140 Feb rua r y PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING
9 References Arefi, H., and M. Hahn, A morphological reconstruction algorithm for separating off-terrain points from terrain points in laser scanning data, International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, 36: Axelsson, P., Processing of laser scanner data - Algorithms and applications, ISPRS Journal of Photogrammetry and Remote Sensing, 54(2): Axelsson, P., DEM generation from laser scanner data using adaptive tin models, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 33(Part 4B): Bai, X., F. Zhou, and T. Jin, Enhancement of DIM small target through modified top-hat transformation under the condition of heavy clutter, Signal Processing, 90(5): Bartels, M., and H. Wei, Threshold-free object and ground point separation in lidar data, Pattern Recognition Letters, 31(10): Bretar, F., and N. Chehata, Terrain modeling from lidar range data in natural landscapes: A predictive and bayesian framework, IEEE Transactions on Geoscience and Remote Sensing, 48(3): Chen, Q., Airborne lidar data processing and information extraction, Photogrammetric Engineering & Remote Sensing, 73(2): Chen, Q., P. Gong, D. Baldocchi, and G. Xie, Filtering airborne laser scanning data with morphological methods, Photogrammetric Engineering & Remote Sensing, 73(2): Elmqvist, M., Ground surface estimation from airborne laser scanner data using active shape models, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 34(Part 3A): Filin, S., and N. Pfeifer, Segmentation of airborne laser scanning data using a slope adaptive neighborhood, ISPRS Journal of Photogrammetry and Remote Sensing, 60(2): Flood, M., Lidar activities and research priorities in the commercial sector, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 34(3/ W4):3 8. Hill, J.M., L. Graham, R. Henry, D. Cotter, and D. Young, Wide-area topographic mapping and applications using airborne light detection and ranging (lidar) technology, Photogrammetric Engineering & Remote Sensing, 66(8): Kobler, A., N. Pfeifer, P. Ogrinc, L. Todorovski, K. Oštir, and S. Džeroski, Repetitive interpolation: A robust algorithm for DTM generation from aerial laser scanner data in forested terrain, Remote Sensing of Environment, 108(1):9 23. Kraus, K., and N. Pfeifer, Determination of terrain models in wooded areas with airborne laser scanner data, ISPRS Journal of Photogrammetry and Remote Sensing, 53(4): Lee, H.S., and N.H. Younan, DTM extraction of lidar returns via adaptive processing, IEEE Transactions on Geoscience and Remote Sensing, 41(9): Li, Y., and H. Wu, DEM extraction from lidar data by morphological gradient, Proceedings of the Fifth International Joint Conference on INC, IMS and IDC, NCM, 2009, pp Liu, X., Airborne lidar for DEM generation: Some critical issues, Progress in Physical Geography, 32(1): Lloyd, C.D., and P.M. Atkinson, Deriving ground surface digital elevation models from lidar data with geostatistics, International Journal of Geographical Information Science, 20(5): Meng, X., L. Wang, and N. Currit, 2009a. Morphology-based building detection from airborne lidar data, Photogrammetric Engineering & Remote Sensing, 75(4): Meng, X., L. Wang, J.L. Silvan-Cardenas, and N. Currit, 2009b. A multi-directional ground filtering algorithm for airborne lidar, ISPRS Journal of Photogrammetry and Remote Sensing, 64(1): Mongus, D., and B. Žalik, Parameter-free ground filtering of lidar data for automatic DTM generation, ISPRS Journal of Photogrammetry and Remote Sensing, 67(0):1 12. Petzold, B., P. Reiss, and W. Stössel, Laser scanning - Surveying and mapping agencies are using a new technique for the derivation of digital terrain models, ISPRS Journal of Photogrammetry and Remote Sensing, 54(2): Pfeifer, N., P. Stadler, and C. Briese, Derivation of digital terrain models in the SCOP++ environment, Proceedings of the OEEPE Workshop on Airborne Laser Scanning and Interferometric SAR for Detailed Digital Elevation Models. Shan, J., and A. Sampath, Urban DEM generation from raw lidar data: A labeling algorithm and its performance, Photogrammetric Engineering & Remote Sensing, 71(2): Silvan-Cardenas, J.L., and L. Wang, A multi-resolution approach for filtering lidar altimetry data, ISPRS Journal of Photogrammetry and Remote Sensing, 61(1): Sithole, G., Filtering of laser altimetry data using a slope adaptive filter, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 34(Part 3W): Sithole, G., and G. Vosselman, Report: ISPRS comparison of filters, Proceedings of ISPRS Commission III, Working Group, Vol. 3. Sithole, G., and G. Vosselman, Experimental comparison of filter algorithms for bare-earth extraction from airborne laser scanning point clouds, ISPRS Journal of Photogrammetry and Remote Sensing, 59(1): Sithole, G., and G. Vosselman, Filtering of airborne laser scanner data based on segmented point clouds, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 36(Part 3W): Sohn, G., and I. Dowman, Terrain surface reconstruction by the use of tetrahedron model with the MDL criterion, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 34(Part 3A): Soille, P., Morphological Image Analysis: Principles and Applications, Springer-Verlag New York. Stoker, J.M., S.K. Greenlee, D.B. Gesch, and J.C. Menig, CLICK: The new USGS center for lidar information coordination and knowledge, Photogrammetric Engineering & Remote Sensing, 72(6): Vosselman, G., Slope based filtering of laser altimetry data, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 33(Part 3B): Wang, C., and Y. Tseng, DEM generation from airborne lidar data by an adaptive dual-directional slope filter, International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 38: Wang, J., and J. Shan, Segmentation of lidar point clouds for building extraction, Proceedings of the ASPRS Annual Conference, Baltimore, Maryland, unpaginated CD-ROM. White, S.A., and Y. Wang, Utilizing DEMs derived from lidar data to analyze morphologic change in the North Carolina coastline, Remote Sensing of Environment, 85(1): Wu, H., Y. Li, J. Li, and J. Gong, A two-step displacement correction algorithm for registration of lidar point clouds and aerial images without orientation parameters, Photogrammetric Engineering & Remote Sensing, 76(10): Zhang, K., S.C. Chen, D. Whitman, M.L. Shyu, J. Yan, and C. Zhang, A progressive morphological filter for removing nonground measurements from airborne lidar data, IEEE Transactions on Geoscience and Remote Sensing, 41(4): Zhang, K., and D. Whitman, Comparison of three algorithms for filtering airborne lidar data, Photogrammetric Engineering & Remote Sensing, 71(3): (Received 06 December 2012; accepted 21 August 2013; final version 24 August 2013) PHOTOGRAMMETRIC ENGINEERING & REMOTE SENSING February
An Improved Top-Hat Filter with Sloped Brim for Extracting Ground Points from Airborne Lidar Point Clouds
Remote Sens. 2014, 6, 12885-12908; doi:10.3390/rs61212885 Article OPEN ACCESS remote sensing ISSN 2072-4292 www.mdpi.com/journal/remotesensing An Improved Top-Hat Filter with Sloped Brim for Extracting
More informationImprovement of the Edge-based Morphological (EM) method for lidar data filtering
International Journal of Remote Sensing Vol. 30, No. 4, 20 February 2009, 1069 1074 Letter Improvement of the Edge-based Morphological (EM) method for lidar data filtering QI CHEN* Department of Geography,
More informationAPPLICABILITY ANALYSIS OF CLOTH SIMULATION FILTERING ALGORITHM FOR MOBILE LIDAR POINT CLOUD
APPLICABILITY ANALYSIS OF CLOTH SIMULATION FILTERING ALGORITHM FOR MOBILE LIDAR POINT CLOUD Shangshu Cai 1,, Wuming Zhang 1,, Jianbo Qi 1,, Peng Wan 1,, Jie Shao 1,, Aojie Shen 1, 1 State Key Laboratory
More informationFOOTPRINTS EXTRACTION
Building Footprints Extraction of Dense Residential Areas from LiDAR data KyoHyouk Kim and Jie Shan Purdue University School of Civil Engineering 550 Stadium Mall Drive West Lafayette, IN 47907, USA {kim458,
More informationChapters 1 7: Overview
Chapters 1 7: Overview Photogrammetric mapping: introduction, applications, and tools GNSS/INS-assisted photogrammetric and LiDAR mapping LiDAR mapping: principles, applications, mathematical model, and
More informationREFINEMENT OF FILTERED LIDAR DATA USING LOCAL SURFACE PROPERTIES INTRODUCTION
REFINEMENT OF FILTERED LIDAR DATA USING LOCAL SURFACE PROPERTIES Suyoung Seo, Senior Research Associate Charles G. O Hara, Associate Research Professor GeoResources Institute Mississippi State University
More informationREGISTRATION OF AIRBORNE LASER DATA TO SURFACES GENERATED BY PHOTOGRAMMETRIC MEANS. Y. Postolov, A. Krupnik, K. McIntosh
REGISTRATION OF AIRBORNE LASER DATA TO SURFACES GENERATED BY PHOTOGRAMMETRIC MEANS Y. Postolov, A. Krupnik, K. McIntosh Department of Civil Engineering, Technion Israel Institute of Technology, Haifa,
More informationGround and Non-Ground Filtering for Airborne LIDAR Data
Cloud Publications International Journal of Advanced Remote Sensing and GIS 2016, Volume 5, Issue 1, pp. 1500-1506 ISSN 2320-0243, Crossref: 10.23953/cloud.ijarsg.41 Research Article Open Access Ground
More informationFiltering Airborne Laser Scanning Data with Morphological Methods
Filtering Airborne Laser Scanning Data with Morphological Methods Qi Chen, Peng Gong, Dennis Baldocchi, and Gengxin Xie Abstract Filtering methods based on morphological operations have been developed
More informationINTEGRATION OF DIFFERENT FILTER ALGORITHMS FOR IMPROVING THE GROUND SURFACE EXTRACTION FROM AIRBORNE LIDAR DATA
8th International Symposium on Spatial Data Quality, 30 May - 1 June 013, Hong Kong INTEGRATION OF DIFFERENT FILTER ALGORITHMS FOR IMPROVING THE GROUND SURFACE EXTRACTION FROM AIRBORNE LIDAR DATA S.S.
More information[Youn *, 5(11): November 2018] ISSN DOI /zenodo Impact Factor
GLOBAL JOURNAL OF ENGINEERING SCIENCE AND RESEARCHES AUTOMATIC EXTRACTING DEM FROM DSM WITH CONSECUTIVE MORPHOLOGICAL FILTERING Junhee Youn *1 & Tae-Hoon Kim 2 *1,2 Korea Institute of Civil Engineering
More informationBuilding Segmentation and Regularization from Raw Lidar Data INTRODUCTION
Building Segmentation and Regularization from Raw Lidar Data Aparajithan Sampath Jie Shan Geomatics Engineering School of Civil Engineering Purdue University 550 Stadium Mall Drive West Lafayette, IN 47907-2051
More informationAnti-Excessive Filtering Model Based on Sliding Window
2nd International Conference on Electrical, Computer Engineering and Electronics (ICECEE 2015) Anti-Excessive Filtering Model Based on Sliding Window Haoang Li 1, a, Weiming Hu 1, b, Jian Yao 1, c and
More informationAUTOMATIC GENERATION OF DIGITAL BUILDING MODELS FOR COMPLEX STRUCTURES FROM LIDAR DATA
AUTOMATIC GENERATION OF DIGITAL BUILDING MODELS FOR COMPLEX STRUCTURES FROM LIDAR DATA Changjae Kim a, Ayman Habib a, *, Yu-Chuan Chang a a Geomatics Engineering, University of Calgary, Canada - habib@geomatics.ucalgary.ca,
More informationA DATA DRIVEN METHOD FOR FLAT ROOF BUILDING RECONSTRUCTION FROM LiDAR POINT CLOUDS
A DATA DRIVEN METHOD FOR FLAT ROOF BUILDING RECONSTRUCTION FROM LiDAR POINT CLOUDS A. Mahphood, H. Arefi *, School of Surveying and Geospatial Engineering, College of Engineering, University of Tehran,
More informationAUTOMATIC BUILDING DETECTION FROM LIDAR POINT CLOUD DATA
AUTOMATIC BUILDING DETECTION FROM LIDAR POINT CLOUD DATA Nima Ekhtari, M.R. Sahebi, M.J. Valadan Zoej, A. Mohammadzadeh Faculty of Geodesy & Geomatics Engineering, K. N. Toosi University of Technology,
More informationAutomated Extraction of Buildings from Aerial LiDAR Point Cloud and Digital Imaging Datasets for 3D Cadastre - Preliminary Results
Automated Extraction of Buildings from Aerial LiDAR Point Cloud and Digital Imaging Datasets for 3D Pankaj Kumar 1*, Alias Abdul Rahman 1 and Gurcan Buyuksalih 2 ¹Department of Geoinformation Universiti
More informationA Method to Create a Single Photon LiDAR based Hydro-flattened DEM
A Method to Create a Single Photon LiDAR based Hydro-flattened DEM Sagar Deshpande 1 and Alper Yilmaz 2 1 Surveying Engineering, Ferris State University 2 Department of Civil, Environmental, and Geodetic
More informationBUILDING DETECTION AND STRUCTURE LINE EXTRACTION FROM AIRBORNE LIDAR DATA
BUILDING DETECTION AND STRUCTURE LINE EXTRACTION FROM AIRBORNE LIDAR DATA C. K. Wang a,, P.H. Hsu a, * a Dept. of Geomatics, National Cheng Kung University, No.1, University Road, Tainan 701, Taiwan. China-
More informationCO-REGISTERING AND NORMALIZING STEREO-BASED ELEVATION DATA TO SUPPORT BUILDING DETECTION IN VHR IMAGES
CO-REGISTERING AND NORMALIZING STEREO-BASED ELEVATION DATA TO SUPPORT BUILDING DETECTION IN VHR IMAGES Alaeldin Suliman, Yun Zhang, Raid Al-Tahir Department of Geodesy and Geomatics Engineering, University
More informationResearch on-board LIDAR point cloud data pretreatment
Acta Technica 62, No. 3B/2017, 1 16 c 2017 Institute of Thermomechanics CAS, v.v.i. Research on-board LIDAR point cloud data pretreatment Peng Cang 1, Zhenglin Yu 1, Bo Yu 2, 3 Abstract. In view of the
More informationThe Effect of Changing Grid Size in the Creation of Laser Scanner Digital Surface Models
The Effect of Changing Grid Size in the Creation of Laser Scanner Digital Surface Models Smith, S.L 1, Holland, D.A 1, and Longley, P.A 2 1 Research & Innovation, Ordnance Survey, Romsey Road, Southampton,
More informationMenglong Yan a b, Thomas Blaschke c, Yu Liu b & Lun Wu b a Key Laboratory of Spatial Information Processing and Application
This article was downloaded by: [Universitat Salzburg] On: 20 July 2012, At: 07:37 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office:
More informationA FFT BASED METHOD OF FILTERING AIRBORNE LASER SCANNER DATA
A FFT BASED METHOD OF FILTERING AIRBORNE LASER SCANNER DATA U. Marmol, J. Jachimski University of Science and Technology in Krakow, Poland Department of Photogrammetry and Remote Sensing Informatics (entice,
More informationA COMPETITION BASED ROOF DETECTION ALGORITHM FROM AIRBORNE LIDAR DATA
A COMPETITION BASED ROOF DETECTION ALGORITHM FROM AIRBORNE LIDAR DATA HUANG Xianfeng State Key Laboratory of Informaiton Engineering in Surveying, Mapping and Remote Sensing (Wuhan University), 129 Luoyu
More informationAutomatic DTM Extraction from Dense Raw LIDAR Data in Urban Areas
Automatic DTM Extraction from Dense Raw LIDAR Data in Urban Areas Nizar ABO AKEL, Ofer ZILBERSTEIN and Yerach DOYTSHER, Israel Key words: LIDAR, DSM, urban areas, DTM extraction. SUMMARY Although LIDAR
More informationAPPLICATIONS OF 3D-EDGE DETECTION FOR ALS POINT CLOUD
APPLICATIONS OF 3D-EDGE DETECTION FOR ALS POINT CLOUD H. Ni a, *, X. G. Lin a, J. X. Zhang b a Institute of Photogrammetry and Remote Sensing, Chinese Academy of Surveying and Mapping, No. 28, Lianhuachixi
More informationSOME stereo image-matching methods require a user-selected
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS, VOL. 3, NO. 2, APRIL 2006 207 Seed Point Selection Method for Triangle Constrained Image Matching Propagation Qing Zhu, Bo Wu, and Zhi-Xiang Xu Abstract In order
More informationAUTOMATIC EXTRACTION OF LARGE COMPLEX BUILDINGS USING LIDAR DATA AND DIGITAL MAPS
AUTOMATIC EXTRACTION OF LARGE COMPLEX BUILDINGS USING LIDAR DATA AND DIGITAL MAPS Jihye Park a, Impyeong Lee a, *, Yunsoo Choi a, Young Jin Lee b a Dept. of Geoinformatics, The University of Seoul, 90
More informationEvaluation and Improvements on Row-Column Order Bias and Grid Orientation Bias of the Progressive Morphological Filter of Lidar Data
Utah State University DigitalCommons@USU T.W. "Doc" Daniel Experimental Forest Quinney Natural Resources Research Library, S.J. and Jessie E. 5-2011 Evaluation and Improvements on Row-Column Order Bias
More informationBUILDING BOUNDARY EXTRACTION FROM HIGH RESOLUTION IMAGERY AND LIDAR DATA
BUILDING BOUNDARY EXTRACTION FROM HIGH RESOLUTION IMAGERY AND LIDAR DATA Liang Cheng, Jianya Gong, Xiaoling Chen, Peng Han State Key Laboratory of Information Engineering in Surveying, Mapping and Remote
More informationUrban DEM Generation from Raw Lidar Data: A Labeling Algorithm and its Performance
Urban DEM Generation from Raw Lidar Data: A Labeling Algorithm and its Performance Jie Shan and Aparajithan Sampath Abstract This paper addresses the separation of ground points from raw lidar data for
More informationBuilding Boundary Tracing and Regularization from Airborne Lidar Point Clouds
Building Boundary Tracing and Regularization from Airborne Lidar Point Clouds Aparajithan Sampath and Jie Shan Abstract Building boundary is necessary for the real estate industry, flood management, and
More informationAirborne Laser Scanning and Derivation of Digital Terrain Models 1
Airborne Laser Scanning and Derivation of Digital Terrain Models 1 Christian Briese, Norbert Pfeifer Institute of Photogrammetry and Remote Sensing Vienna University of Technology Gußhausstraße 27-29,
More informationInvestigation of Sampling and Interpolation Techniques for DEMs Derived from Different Data Sources
Investigation of Sampling and Interpolation Techniques for DEMs Derived from Different Data Sources FARRAG ALI FARRAG 1 and RAGAB KHALIL 2 1: Assistant professor at Civil Engineering Department, Faculty
More informationA METHOD TO PREDICT ACCURACY OF LEAST SQUARES SURFACE MATCHING FOR AIRBORNE LASER SCANNING DATA SETS
A METHOD TO PREDICT ACCURACY OF LEAST SQUARES SURFACE MATCHING FOR AIRBORNE LASER SCANNING DATA SETS Robert Pâquet School of Engineering, University of Newcastle Callaghan, NSW 238, Australia (rpaquet@mail.newcastle.edu.au)
More informationPolyhedral Building Model from Airborne Laser Scanning Data**
GEOMATICS AND ENVIRONMENTAL ENGINEERING Volume 4 Number 4 2010 Natalia Borowiec* Polyhedral Building Model from Airborne Laser Scanning Data** 1. Introduction Lidar, also known as laser scanning, is a
More informationHEURISTIC FILTERING AND 3D FEATURE EXTRACTION FROM LIDAR DATA
HEURISTIC FILTERING AND 3D FEATURE EXTRACTION FROM LIDAR DATA Abdullatif Alharthy, James Bethel School of Civil Engineering, Purdue University, 1284 Civil Engineering Building, West Lafayette, IN 47907
More informationAutomatic Building Extrusion from a TIN model Using LiDAR and Ordnance Survey Landline Data
Automatic Building Extrusion from a TIN model Using LiDAR and Ordnance Survey Landline Data Rebecca O.C. Tse, Maciej Dakowicz, Christopher Gold and Dave Kidner University of Glamorgan, Treforest, Mid Glamorgan,
More informationA Generalized Adaptive Mathematical Morphological Filter for LIDAR Data
Florida International University FIU Digital Commons FIU Electronic Theses and Dissertations University Graduate School 11-14-2013 A Generalized Adaptive Mathematical Morphological Filter for LIDAR Data
More informationFILTERING OF DIGITAL ELEVATION MODELS
FILTERING OF DIGITAL ELEVATION MODELS Dr. Ing. Karsten Jacobsen Institute for Photogrammetry and Engineering Survey University of Hannover, Germany e-mail: jacobsen@ipi.uni-hannover.de Dr. Ing. Ricardo
More informationGenerate Digital Elevation Models Using Laser Altimetry (LIDAR) Data. Christopher Weed
Generate Digital Elevation Models Using Laser Altimetry (LIDAR) Data Christopher Weed Final Report EE 381K Multidimensional Digital Signal Processing December 11, 2000 Abstract A Laser Altimetry (LIDAR)
More informationExperiments on Generation of 3D Virtual Geographic Environment Based on Laser Scanning Technique
Experiments on Generation of 3D Virtual Geographic Environment Based on Laser Scanning Technique Jie Du 1, Fumio Yamazaki 2 Xiaoyong Chen 3 Apisit Eiumnoh 4, Michiro Kusanagi 3, R.P. Shrestha 4 1 School
More informationTHREE-DIMENSIONAL MODELLING OF BREAKLINES FROM AIRBORNE LASER SCANNER DATA
THREE-DIMENSIONAL MODELLING OF BREAKLINES FROM AIRBORNE LASER SCANNER DATA Christian Briese Institute of Photogrammetry and Remote Sensing Vienna University of Technology, Gußhausstraße 27-29, A-1040 Vienna,
More informationOBJECT-BASED CLASSIFICATION OF URBAN AIRBORNE LIDAR POINT CLOUDS WITH MULTIPLE ECHOES USING SVM
OBJECT-BASED CLASSIFICATION OF URBAN AIRBORNE LIDAR POINT CLOUDS WITH MULTIPLE ECHOES USING SVM J. X. Zhang a, X. G. Lin a, * a Key Laboratory of Mapping from Space of State Bureau of Surveying and Mapping,
More informationGenerate Digital Elevation Models Using Laser Altimetry (LIDAR) Data
Generate Digital Elevation Models Using Laser Altimetry (LIDAR) Data Literature Survey Christopher Weed October 2000 Abstract Laser altimetry (LIDAR) data must be processed to generate a digital elevation
More informationQUALITY CONTROL METHOD FOR FILTERING IN AERIAL LIDAR SURVEY
QUALITY CONTROL METHOD FOR FILTERING IN AERIAL LIDAR SURVEY Y. Yokoo a, *, T. Ooishi a, a Kokusai Kogyo CO., LTD.,Base Information Group, 2-24-1 Harumicho Fuchu-shi, Tokyo, 183-0057, JAPAN - (yasuhiro_yokoo,
More informationAN IMPROVED CLASSIFICATION APPROACH FOR LIDAR POINT CLOUDS ON TEXAS COASTAL AREAS
AN IMPROVED CLASSIFICATION APPROACH FOR LIDAR POINT CLOUDS ON TEXAS COASTAL AREAS L. Su, J. Gibeaut Harte Research Institute for Gulf of Mexico Studies, Texas A&M University - Corpus Christi, Corpus Christi,
More informationDIGITAL TERRAIN MODELS
DIGITAL TERRAIN MODELS 1 Digital Terrain Models Dr. Mohsen Mostafa Hassan Badawy Remote Sensing Center GENERAL: A Digital Terrain Models (DTM) is defined as the digital representation of the spatial distribution
More informationSYNERGY BETWEEN AERIAL IMAGERY AND LOW DENSITY POINT CLOUD FOR AUTOMATED IMAGE CLASSIFICATION AND POINT CLOUD DENSIFICATION
SYNERGY BETWEEN AERIAL IMAGERY AND LOW DENSITY POINT CLOUD FOR AUTOMATED IMAGE CLASSIFICATION AND POINT CLOUD DENSIFICATION Hani Mohammed Badawy a,*, Adel Moussa a,b, Naser El-Sheimy a a Dept. of Geomatics
More informationCOMBINING HIGH SPATIAL RESOLUTION OPTICAL AND LIDAR DATA FOR OBJECT-BASED IMAGE CLASSIFICATION
COMBINING HIGH SPATIAL RESOLUTION OPTICAL AND LIDAR DATA FOR OBJECT-BASED IMAGE CLASSIFICATION Ruonan Li 1, Tianyi Zhang 1, Ruozheng Geng 1, Leiguang Wang 2, * 1 School of Forestry, Southwest Forestry
More informationTERRAIN MODELING AND AIRBORNE LASER DATA CLASSIFICATION USING MULTIPLE PASS FILTERING
TERRAIN MODELING AND AIRBORNE LASER DATA LASSIFIATION USING MULTIPLE PASS FILTERING Frédéric Bretar a,b, Matthieu hesnier a, Michel Roux b, Marc Pierrot-Deseilligny a a Institut Géographique National 2-4
More informationAUTOMATIC EXTRACTION OF BUILDING FEATURES FROM TERRESTRIAL LASER SCANNING
AUTOMATIC EXTRACTION OF BUILDING FEATURES FROM TERRESTRIAL LASER SCANNING Shi Pu and George Vosselman International Institute for Geo-information Science and Earth Observation (ITC) spu@itc.nl, vosselman@itc.nl
More informationAPPENDIX E2. Vernal Pool Watershed Mapping
APPENDIX E2 Vernal Pool Watershed Mapping MEMORANDUM To: U.S. Fish and Wildlife Service From: Tyler Friesen, Dudek Subject: SSHCP Vernal Pool Watershed Analysis Using LIDAR Data Date: February 6, 2014
More informationSurface Creation & Analysis with 3D Analyst
Esri International User Conference July 23 27 San Diego Convention Center Surface Creation & Analysis with 3D Analyst Khalid Duri Surface Basics Defining the surface Representation of any continuous measurement
More informationTHE USE OF ANISOTROPIC HEIGHT TEXTURE MEASURES FOR THE SEGMENTATION OF AIRBORNE LASER SCANNER DATA
THE USE OF ANISOTROPIC HEIGHT TEXTURE MEASURES FOR THE SEGMENTATION OF AIRBORNE LASER SCANNER DATA Sander Oude Elberink* and Hans-Gerd Maas** *Faculty of Civil Engineering and Geosciences Department of
More informationADAPTIVE FILTERING OF AERIAL LASER SCANNING DATA
ISPRS Workshop on Laser Scanning 2007 and SilviLaser 2007, Espoo, September 12-14, 2007, Finland ADAPTIVE FILTERING OF AERIAL LASER SCANNING DATA Gianfranco Forlani a, Carla Nardinocchi b1 a Dept. of Civil
More informationCOMPARISON OF TREE EXTRACTION FROM INTENSITY DROP AND FROM MULTIPLE RETURNS IN ALS DATA
COMPARISON OF TREE EXTRACTION FROM INTENSITY DROP AND FROM MULTIPLE RETURNS IN ALS DATA C.Örmeci a, S.Cesur b a ITU, Civil Engineering Faculty, 80626 Maslak Istanbul, Turkey ormeci@itu.edu.tr b ITU, Informatics
More informationA Progressive Morphological Filter for Removing Nonground Measurements From Airborne LIDAR Data
872 IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING, VOL. 41, NO. 4, APRIL 2003 A Progressive Morphological Filter for Removing Nonground Measurements From Airborne LIDAR Data Keqi Zhang, Shu-Ching
More informationNATIONWIDE POINT CLOUDS AND 3D GEO- INFORMATION: CREATION AND MAINTENANCE GEORGE VOSSELMAN
NATIONWIDE POINT CLOUDS AND 3D GEO- INFORMATION: CREATION AND MAINTENANCE GEORGE VOSSELMAN OVERVIEW National point clouds Airborne laser scanning in the Netherlands Quality control Developments in lidar
More informationLand Cover Stratified Accuracy Assessment For Digital Elevation Model derived from Airborne LIDAR Dade County, Florida
Land Cover Stratified Accuracy Assessment For Digital Elevation Model derived from Airborne LIDAR Dade County, Florida FINAL REPORT Submitted October 2004 Prepared by: Daniel Gann Geographic Information
More informationAN EFFICIENT METHOD FOR AUTOMATIC ROAD EXTRACTION BASED ON MULTIPLE FEATURES FROM LiDAR DATA
AN EFFICIENT METHOD FOR AUTOMATIC ROAD EXTRACTION BASED ON MULTIPLE FEATURES FROM LiDAR DATA Y. Li a, X. Hu b, H. Guan c, P. Liu d a School of Civil Engineering and Architecture, Nanchang University, 330031,
More informationAUTOMATIC EXTRACTION OF ROAD MARKINGS FROM MOBILE LASER SCANNING DATA
AUTOMATIC EXTRACTION OF ROAD MARKINGS FROM MOBILE LASER SCANNING DATA Hao Ma a,b, Zhihui Pei c, Zhanying Wei a,b,*, Ruofei Zhong a a Beijing Advanced Innovation Center for Imaging Technology, Capital Normal
More informationEXTRACTING SURFACE FEATURES OF THE NUECES RIVER DELTA USING LIDAR POINTS INTRODUCTION
EXTRACTING SURFACE FEATURES OF THE NUECES RIVER DELTA USING LIDAR POINTS Lihong Su, Post-Doctoral Research Associate James Gibeaut, Associate Research Professor Harte Research Institute for Gulf of Mexico
More informationGENERATING BUILDING OUTLINES FROM TERRESTRIAL LASER SCANNING
GENERATING BUILDING OUTLINES FROM TERRESTRIAL LASER SCANNING Shi Pu International Institute for Geo-information Science and Earth Observation (ITC), Hengelosestraat 99, P.O. Box 6, 7500 AA Enschede, The
More informationMONO-IMAGE INTERSECTION FOR ORTHOIMAGE REVISION
MONO-IMAGE INTERSECTION FOR ORTHOIMAGE REVISION Mohamed Ibrahim Zahran Associate Professor of Surveying and Photogrammetry Faculty of Engineering at Shoubra, Benha University ABSTRACT This research addresses
More informationMATLAB Tools for LIDAR Data Conversion, Visualization, and Processing
MATLAB Tools for LIDAR Data Conversion, Visualization, and Processing Xiao Wang a, Kaijing Zhou a, Jie Yang a, Yilong Lu *a a Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 ABSTRACT
More informationHierarchical Recovery of Digital Terrain Models from Single and Multiple Return Lidar Data
MMS04-330.qxd 3/3/05 3:42 PM Page 425 Hierarchical Recovery of Digital Terrain Models from Single and Multiple Return Lidar Data Yong Hu and C. Vincent Tao Abstract A hierarchical terrain recovery approach
More informationLIDAR MAPPING FACT SHEET
1. LIDAR THEORY What is lidar? Lidar is an acronym for light detection and ranging. In the mapping industry, this term is used to describe an airborne laser profiling system that produces location and
More informationWAVELET AND SCALE-SPACE THEORY IN SEGMENTATION OF AIRBORNE LASER SCANNER DATA
WAVELET AND SCALE-SPACE THEORY IN SEGMENTATION OF AIRBORNE LASER SCANNER DATA T.Thuy VU, Mitsuharu TOKUNAGA Space Technology Applications and Research Asian Institute of Technology P.O. Box 4 Klong Luang,
More informationA QUALITY ASSESSMENT METHOD FOR 3D ROAD POLYGON OBJECTS
A QUALITY ASSESSMENT METHOD FOR 3D ROAD POLYGON OBJECTS Lipeng Gao a, b, Wenzhong Shi b, *, YiliangWan a, b a School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, China gaolipengcumt@gmail.com,
More informationOVER the past decade, Light Detection and Ranging
340 IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, VOL. 7, NO. 1, JANUARY 2014 Computationally Efficient Method for the Generation of a Digital Terrain Model From Airborne
More informationContents of Lecture. Surface (Terrain) Data Models. Terrain Surface Representation. Sampling in Surface Model DEM
Lecture 13: Advanced Data Models: Terrain mapping and Analysis Contents of Lecture Surface Data Models DEM GRID Model TIN Model Visibility Analysis Geography 373 Spring, 2006 Changjoo Kim 11/29/2006 1
More informationDOCUMENTATION AND VISUALIZATION OF ANCIENT BURIAL MOUNDS BY HELICOPTER LASER SURVEYING
DOCUMENTATION AND VISUALIZATION OF ANCIENT BURIAL MOUNDS BY HELICOPTER LASER SURVEYING Tsutomu Kakiuchi a *, Hirofumi Chikatsu b, Haruo Sato c a Aero Asahi Corporation, Development Management Division,
More informationA Hierarchial Model for Visual Perception
A Hierarchial Model for Visual Perception Bolei Zhou 1 and Liqing Zhang 2 1 MOE-Microsoft Laboratory for Intelligent Computing and Intelligent Systems, and Department of Biomedical Engineering, Shanghai
More informationTerrestrial Laser Scanning: Applications in Civil Engineering Pauline Miller
Terrestrial Laser Scanning: Applications in Civil Engineering Pauline Miller School of Civil Engineering & Geosciences Newcastle University Overview Laser scanning overview Research applications geometric
More informationADVANCED TERRAIN PROCESSING: ANALYTICAL RESULTS OF FILLING VOIDS IN REMOTELY SENSED DATA TERRAIN INPAINTING
ADVANCED TERRAIN PROCESSING: ANALYTICAL RESULTS OF FILLING VOIDS IN REMOTELY SENSED DATA J. Harlan Yates Patrick Kelley Josef Allen Mark Rahmes Harris Corporation Government Communications Systems Division
More informationIMPROVED TARGET DETECTION IN URBAN AREA USING COMBINED LIDAR AND APEX DATA
IMPROVED TARGET DETECTION IN URBAN AREA USING COMBINED LIDAR AND APEX DATA Michal Shimoni 1 and Koen Meuleman 2 1 Signal and Image Centre, Dept. of Electrical Engineering (SIC-RMA), Belgium; 2 Flemish
More informationN.J.P.L.S. An Introduction to LiDAR Concepts and Applications
N.J.P.L.S. An Introduction to LiDAR Concepts and Applications Presentation Outline LIDAR Data Capture Advantages of Lidar Technology Basics Intensity and Multiple Returns Lidar Accuracy Airborne Laser
More informationCOMBINATION OF IMAGE AND LIDAR DATA FOR BUILDING AND TREE EXTRACTION
COMBINATION OF IMAGE AND LIDAR DATA FOR BUILDING AND TREE EXTRACTION Demir, N. 1, Baltsavias, E. 1 1- (demir,manos@geod.baug.ethz.ch) Institute of Geodesy and Photogrammetry, ETH Zurich, CH-8093, Zurich,
More informationNew Requirements for the Relief in the Topographic Databases of the Institut Cartogràfic de Catalunya
New Requirements for the Relief in the Topographic Databases of the Institut Cartogràfic de Catalunya Blanca Baella, Maria Pla Institut Cartogràfic de Catalunya, Barcelona, Spain Abstract Since 1983 the
More informationIMPROVING THE ACCURACY OF DIGITAL TERRAIN MODELS
STUDIA UNIV. BABEŞ BOLYAI, INFORMATICA, Volume XLV, Number 1, 2000 IMPROVING THE ACCURACY OF DIGITAL TERRAIN MODELS GABRIELA DROJ Abstract. The change from paper maps to GIS, in various kinds of geographical
More informationRepetitive interpolation: A robust algorithm for DTM generation from Aerial Laser Scanner Data in forested terrain
Remote Sensing of Environment 108 (2007) 9 23 www.elsevier.com/locate/rse Repetitive interpolation: A robust algorithm for DTM generation from Aerial Laser Scanner Data in forested terrain Andrej Kobler
More informationMODELLING FOREST CANOPY USING AIRBORNE LIDAR DATA
MODELLING FOREST CANOPY USING AIRBORNE LIDAR DATA Jihn-Fa JAN (Taiwan) Associate Professor, Department of Land Economics National Chengchi University 64, Sec. 2, Chih-Nan Road, Taipei 116, Taiwan Telephone:
More informationPresented at the FIG Congress 2018, May 6-11, 2018 in Istanbul, Turkey
Presented at the FIG Congress 2018, May 6-11, 2018 in Istanbul, Turkey Evangelos MALTEZOS, Charalabos IOANNIDIS, Anastasios DOULAMIS and Nikolaos DOULAMIS Laboratory of Photogrammetry, School of Rural
More informationSURFACE ESTIMATION BASED ON LIDAR. Abstract
Published in: Proceedings of the ASPRS Annual Conference. St. Louis, Missouri, April 2001. SURFACE ESTIMATION BASED ON LIDAR Wolfgang Schickler Anthony Thorpe Sanborn 1935 Jamboree Drive, Suite 100 Colorado
More informationI. Project Title Light Detection and Ranging (LIDAR) Processing
I. Project Title Light Detection and Ranging (LIDAR) Processing II. Lead Investigator Ryan P. Lanclos Research Specialist 107 Stewart Hall Department of Geography University of Missouri Columbia Columbia,
More informationBUILDING MODEL RECONSTRUCTION FROM DATA INTEGRATION INTRODUCTION
BUILDING MODEL RECONSTRUCTION FROM DATA INTEGRATION Ruijin Ma Department Of Civil Engineering Technology SUNY-Alfred Alfred, NY 14802 mar@alfredstate.edu ABSTRACT Building model reconstruction has been
More informationFULLY CONVOLUTIONAL NETWORKS FOR GROUND CLASSIFICATION FROM LIDAR POINT CLOUDS
FULLY CONVOLUTIONAL NETWORKS FOR GROUND CLASSIFICATION FROM LIDAR POINT CLOUDS A. Rizaldy 1,*, C. Persello 1, C.M. Gevaert 1, S.J. Oude Elberink 1 1 ITC, Faculty of Geo-Information Science and Earth Observation,
More informationAssimilation of Break line and LiDAR Data within ESRI s Terrain Data Structure (TDS) for creating a Multi-Resolution Terrain Model
Assimilation of Break line and LiDAR Data within ESRI s Terrain Data Structure (TDS) for creating a Multi-Resolution Terrain Model Tarig A. Ali Department of Civil Engineering American University of Sharjah,
More informationRECOGNISING STRUCTURE IN LASER SCANNER POINT CLOUDS 1
RECOGNISING STRUCTURE IN LASER SCANNER POINT CLOUDS 1 G. Vosselman a, B.G.H. Gorte b, G. Sithole b, T. Rabbani b a International Institute of Geo-Information Science and Earth Observation (ITC) P.O. Box
More informationInternational Journal of Civil Engineering and Geo-Environment. Close-Range Photogrammetry For Landslide Monitoring
International Journal of Civil Engineering and Geo-Environment Journal homepage:http://ijceg.ump.edu.my ISSN:21802742 Close-Range Photogrammetry For Landslide Monitoring Munirah Bt Radin Mohd Mokhtar,
More informationSummary of Research and Development Efforts Necessary for Assuring Geometric Quality of Lidar Data
American Society for Photogrammetry and Remote Sensing (ASPRS) Summary of Research and Development Efforts Necessary for Assuring Geometric Quality of Lidar Data 1 Summary of Research and Development Efforts
More informationUse of Shape Deformation to Seamlessly Stitch Historical Document Images
Use of Shape Deformation to Seamlessly Stitch Historical Document Images Wei Liu Wei Fan Li Chen Jun Sun Satoshi Naoi In China, efforts are being made to preserve historical documents in the form of digital
More informationBonemapping: A LiDAR Processing and Visualization Approach and Its Applications
Bonemapping: A LiDAR Processing and Visualization Approach and Its Applications Thomas J. Pingel Northern Illinois University National Geography Awareness Week Lecture Department of Geology and Geography
More informationAvailable online at ScienceDirect. Procedia Environmental Sciences 36 (2016 )
Available online at www.sciencedirect.com ScienceDirect Procedia Environmental Sciences 36 (2016 ) 184 190 International Conference on Geographies of Health and Living in Cities: Making Cities Healthy
More informationAalborg Universitet. Published in: Accuracy Publication date: Document Version Early version, also known as pre-print
Aalborg Universitet A method for checking the planimetric accuracy of Digital Elevation Models derived by Airborne Laser Scanning Høhle, Joachim; Øster Pedersen, Christian Published in: Accuracy 2010 Publication
More informationOn the Selection of an Interpolation Method for Creating a Terrain Model (TM) from LIDAR Data
On the Selection of an Interpolation Method for Creating a Terrain Model (TM) from LIDAR Data Tarig A. Ali Department of Technology and Geomatics East Tennessee State University P. O. Box 70552, Johnson
More informationApplication and Precision Analysis of Tree height Measurement with LiDAR
Application and Precision Analysis of Tree height Measurement with LiDAR Hejun Li a, BoGang Yang a,b, Xiaokun Zhu a a Beijing Institute of Surveying and Mapping, 15 Yangfangdian Road, Haidian District,
More informationRECOMMENDATION ITU-R P DIGITAL TOPOGRAPHIC DATABASES FOR PROPAGATION STUDIES. (Question ITU-R 202/3)
Rec. ITU-R P.1058-1 1 RECOMMENDATION ITU-R P.1058-1 DIGITAL TOPOGRAPHIC DATABASES FOR PROPAGATION STUDIES (Question ITU-R 202/3) Rec. ITU-R P.1058-1 (1994-1997) The ITU Radiocommunication Assembly, considering
More information