Research on the applicability of E-Foto Open Source Software To Server Teaching and Researching in Universities of Viet Nam

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1 Research on the applicability of E-Foto Open Source Software To Server Teaching and Researching in Universities of Viet Nam DUY Nguyen Ba 1, a, GIANG Tran Thi Huong 2,b HAU Ninh Hoa 3, NGOC Tran Thi Bich 3 1 Photogrammetry and Remote Sensing Department, Hanoi University of Mining and Geology 2 Cartography Department, Hanoi University of Mining and Geology 3 Hanoi University of Mining and Geology a basduy2309@gmail.com, b giangde0912@gmail.com Keywords: Open source, Photogrammetry, Education and Training Abstract. The E-foto project (A free GNU/GPL educational digital photogrammetric workstation) has been in development at the Photogrammetry Lab of the Rio de Janeiro State University s School of Engineering since The idea behind the E-Foto project was to offer a simple set of software (a free Digital Photogrammetric Workstation) that could help students understand the principles behind Photogrammetry, thus bypassing eventual costs that would have barred many from learning about Photogrammetry. This objective was reached through the development of free and user-friendly photogrammetric software.this project is multidisciplinary. It involves several fields of knowledge, including Mathematical Modeling, Geodesy, Photogrammetry, and Software Engineering.The project is based on two main principles (pillars): freedom and self-teaching. The final idea is to lead the students to fully understand the principles behind Photogrammetry by reading the e-book, using the software, taking a look at its source code, and even modifying it or developing new modules for it. This paper focuses on the presentation of the abilities of E-Foto in researching and teaching in the Vietnam s universities. Compared to some other free software initiatives and other commercial software, it is not only easier to understand but also more complete, its targeted user is rather professionals (surveyor, photographer, architects, archaeologist, and geomophologist) and students who are working and studying in universities. E-foto s objective is to provide the full implementation of a digital photogrammetric workstation licensed as free software. Its basic proposal is to be a multi-platform set of software (Linux, Windows and MacOS) that can be ran in simple machines (that are not necessarily state-of-the-art computers), allowing basic stereoscopic viewing through anaglyph glasses, which can easily be purchased from online stores. 1. Introduction Photogrammetric is an indirect method of measurement through images or other obtained sources of information of the measured object. By which we can determine the position, shape, size and mutual relationships of the measured objects. Along with the continuous development of information technology, photo measures is increasing in number of applications in manufacture such as: the establishment of digital elevation model (DEM), orthogonal image set, non-terrain photo measures, mechanical industries, agriculture... And especially in the work of surveying and mapping of the rates by a digital measuring technology in our country are also using the advanced achievements of information technology. Specifically, the system of software servicing image measurement in production facilities mostly is dedicated software such as: Intergraph software, this software requires high computer configuration and price. With the theme: "study on the applicability of E-photo open source software to serve teaching and practice in photo measures will help students understand more about the nature of the problem

2 in photo measures by which software implement, and in particular to improve the spirit of self-study, research of students. 2. E-foto software E-foto is an open-source software, free for teaching and student research. E-foto project developed in the laboratory of Optical Survey, Faculty of Engineering, University of Rio de Janeiro since The main functions of e-foto software: Implement interior and exterior orientation problems for a single photo Implement relative and absolute orientation problems for a stereo-pair image Construct digital elevation models Image setting Re-divide the Grey Level (GL) and so on. Picture introduce to E-foto s home page There are a lot of problems in photo measures, there are four basic problems, namely: the problem of interior and exterior orientation for a single image, the problem of relative and absolute orientation for a stereo-pair image. The content of the subject studied in depth on two problems of interior and exterior orientation for a single photograph Digital mapping technology process (single image) by E-foto

3 The parameters of the camera Aviation photos file Ground Control Point Construct project (project) Implement interior orientation ( Interior Orientation ) Implement exterior orientation ( Exterior Orientation ) 2.2. Experimental use e-foto software in digital mapping technology (single image measurement) About the study area Experimental zone belongs to the campus of Purdue University (Purdue), is a public university in West Lafayette city, Indiana State, United States The preparation Gather measurement documentation on the study area: - Foreign Industry data: Coordinates and elevation of Ground Control Points, the terrain area map, the document on the mapped area... - Image documentation: photo file. Test results of the camera (the value of the interior orientation factor, the coordinates of the frame sign, the material lens distortion coefficients, etc.) Project building This is the process of entering the necessary parameters (taken from the results of testing of the camera) and select the path to the image file of the mapped area used for work as required by E-foto, including: - Declare the title of the project (Project header) - Declare the information about the terrain of mapped area (Terrain - Declare the parameters of the Camera or Sensor (Sensor) - Declare the fly capture parameters (Flight) - Choose the path to the image file (Images) - Declare the coordinates of the foreign industry control point (Point) Interior orientation implementation The interior orientation elements of measured image are geometric factors determine the space location of the capture center S to the image plane to restore the beam as the one when taking picture. These include: main points image o and focus of the camera f k. For interior orientation digital image is the transition from digital image coordinates to image plane coordinates. Here we apply the convert model Affine.

4 We need to measure the image coordinates (row, col) corresponding to the image plane coordinates of the key frame, by using the keyboard mouse and functional tools of the software E-foto: Move, Zoom, Setmark, Fitview. Then click on the interior orientation module. E-foto software will carry out interior orientation problem and give out result tables: 6 coefficient anffine, error correction equation table and mean square error of unit weight m Exterior orientation The purpose of the exterior orientation problem is to help identify the exterior orientation elements of the image (coordinates of capture center S in geodetic coordinates and the rotation angle φ, ω, κ of measured image). Similar to the interior orientation process, we also need to determine the image coordinates (col, lim) of Ground Control Points, we use the support tools Zoom to zoom, Move to move and finally use support tools Set point to catch that exact location. After having determined the image coordinates (row, column) and the corresponding image plane coordinates to geodetic coordinates of the Ground Control Points, click on the interior orientation module. E-foto software will perform exterior orientation problem and give out the results table: the value of six exterior orientation elements, error correction equation table and mean square error of unit weight m 0.

5 3. Experimental results calculated on excel 3.1. Interior orientation problem Root t resolution Results calculated on excel E-foto s results x 0 116, ,01134 y -115, , a 1-0, ,02400 a 2-0, ,00006 b 1-0, ,00006 b 0, ,

6 Corrections V(mm) Results calculated on excel E-foto s results V 1 0, ,00481 V 2 0, ,00562 V 3 0, ,00041 V 4 0, ,00989 V 5-0, ,01665 V 6 0, ,01151 V 7-0, ,00213 V 8 0, ,00195 V 9 0, ,00794 V 10-0, ,01025 V 11-0, ,00165 V 12-0, ,00524 V 13 0, ,01260 V 14-0, ,01329 V 15-0, ,00532 V 16-0, ,00020 Mean square error of unit weight m 0 = 0,010643(mm) m 0 = 0,010643(mm) 3.2. Exterior orientation problem Corrections V(mm) Results calculated on excel V 1 0,0299 0,0299 V 2-0,293-0,293 V 3-0,127-0,127 V 4 0,046 0,046 V 5-0,175-0,175 V 6 0,155 0,155 V 7 0,082 0,082 V 8 0,059 0,58 V 9 0,198 0,198 V 10 0,027 0,028 Mean square error of unit weight m 0 =0,229(mm) E-foto s results m 0 =010643(mm)

7 Root Results calculated on excel E-foto s results resolution ω 3 0, ,00584 φ 3-0, ,00480 κ 3 1, ,55801 X , ,453 Y , ,127 Z 3 540, , Comments and conclusions 4.1. Comments By comparison, the calculated results on excel and the results of the E-foto is similar. However, the results of mean square error of unit weight on software are false. This is a drawback but also a benefit of E-foto open source software. Disadvantages: E-photo is not a commercial software. It is open-source software. Therefore, there may have some inaccurate parts. Advantages: E-foto was developed for the purpose of application in teaching research. Hence, students can correct the above inaccuracies by entering to see the code of the studied problem and revise Conclusions - In terms of applications in practical manufacture: the development of the E-foto not intend to surpass the commercial software solutions in their fields because of the scale and speed of processors is not high. - On the application in research and teaching: in production, E-foto does not provide high performance but in teaching, E-foto is fully able to meet the different needs of users, namely: E-foto is an open-source software, totally free, students can download and install easily, can learn the code of the problem that E-foto implement, through which can develop new modules in the software. For teachers: E-foto software makes lessons more vivid and easy to understand. The basic problem in photo measures is addressed thoroughly and clearly illustrated. On the home page of E-foto, there are full documentations and user manual. Students can study and learn, develop their creative abilities. These are special features that we would like to emphasize: the ability to research and creativity. References [1] Website: [2] Website: [3] Website: [4] E-foto: An educational digital photogrammetric workstation