SPAR, ELMF 2013, Amsterdam. Laser Scanning on the UK Highways Agency Network. Hamish Grierson Blom Uk

Transcription

1 SPAR, ELMF 2013, Amsterdam Laser Scanning on the UK Highways Agency Network Hamish Grierson Blom Uk

2 Blom UK Part of the Blom Group Blom Group - Europe s largest aerial survey company Offices in 13 European countries Head office - Oslo, Norway 600 highly qualified staff Access to the latest technology 16 aerial survey aircraft and 2 helicopters 11 LiDAR scanners and 10 cameras Business Concept Aerial acquisition Data Processing Data Delivery Database creation

3 Blom Services Aerial Survey Photography Laser Scanning (LiDAR) Terrestrial Land Surveys Mapping 3D City Modelling Satellite Data and Imagery

4 Highways Agency Responsible for operating, maintaining, and improving the strategic road network in England. 6900km of motorway and trunk roads 2.5% of total road network 34% of all road travel 67% of all lorry freight travel

5 Highways Agency Responsible for operating, maintaining, and improving the strategic road network in England. 6900km of motorway and trunk roads 2.5% of total road network 34% of all road travel 67% of all lorry freight travel Network split in to 6 regions with 13 Management Area Teams Each managed and maintained by Managing Agent Contractor (MAC) Responsible for the maintenance of the roads in their area All other roads managed by Local Authority s

6 HA Survey Projects Rotary Wing 2004 to 2010 HA Framework Contract to Undertake Lidar Surveys Topeye Rotary Wing capture 1100km (16%) of the HA Network 19 Projects, including M25 Rapid Widening M6 Jct 11a to 19 M1 Jct 6a to 13 M1 Jct 28 to 32 M4 Jct 3 to 12 Products Mapping Ortho mosaic Contours

7 HA Survey Projects Rotary Wing Topeye MkIII Developed, Built and Operated by Blom Sweden Riegl LMS Scanner Q680i or Q560 Digital Camera IMU Leica RCD 30 or Phase One ixa 180 Applanix POS AV 510 HA Requirements 30 points sq metre 4cm GSD Imagery Accuracy +- 35mm Vertical +- 75mm Horizontal

8 HA Survey Projects Rotary Wing Topeye MkIII data Consistent Swath Width Consistent Point Density Vegetation penetration Consistent GNSS Positioning accuracy Data voids Bridges, Tunnels

9 HA Survey Projects Mobile Lidar Capture since ,600km (52%) of Network Each direction driven twice 15,600km of on-line data 5 of 13 HA Areas Captured Projects Area 4 450km Area 6 500km Area 7 710km (twice) Area 9 770km Area km Products Safety Barrier Heights Asset Inventory Mapping

10 HA Survey Projects Mobile Lidar Optech Lynx V200 Joint venture between Blum UK and the IBI Group Two Laser scanners Laser Measurement Rate kHz Scan Frequency Hz Two Cameras 4 Mega Pixel Up to 5 frames per second Positioning Applanix LV 410 IMU 2 GNSS receivers DMI Vehicle Nissan Pathfinder

11 HA Survey Projects Mobile Lidar Optech Lynx V200 Mobile data Low to ground (2.5m above road surface) Irregular point density Even point density across adjacent carriageways Short range (<50m) >8m range density drops off Shadowing Fences, Vegetation, Vehicles Potential for Poor Positioning accuracy Bridges Tunnels Buildings Trees Vehicles

12 HA Survey Projects Data Processing Positioning Topeye Applanix POSPac MMS Point Cloud QC TEPP (TopEye Post Processing) Range Data Sbet Calibration Terrasolid TerraScan TerraMatch TerraModel Positioning Lynx Applanix POSPac MMS Point Cloud QC Dashmap or LMS Range Data Sbet Calibration Terrasolid TerraScan TerraMatch TerraModel

13 Case Study - M4 Junction 8 to 12 Topeye MkIII Survey June 2010 Optech Lynx Survey June 2013

14 M4 Junction 8 to 12 Topeye Survey Flown June 2010 Topeye MkIII 300m AGL 1 Pass, 350m swath Density <30 pt sq m Imagery 4cm GSD HPSM 20mm accuracy Products Mapping Orthophoto Contours AVI Cross Section

15 M4 Junction 8 to 12 Lynx Survey Driven June passes Lane 1 and 2 both directions 3 hours capture Density <500 pt sq m Capture speed 100kph No imagery Deliverables 1:500 Mapping CAD and MX

16 M4 Junction 8 to 12 Bridge Control Data Topeye Project 12 Overbridges Leica Total Station 2 Setups per Bridge Each road marking observed from both stations Optech Lynx Project 5 Overbridges Faro Focus 3D Scanner 2 setups per bridge 360 degree scan

17 Data Comparison Elevation Comparison to 2010 and 2013 control data Elevation Check 2013 mobile laser data to 2010 control Number of Bridge control points ave dz min dz max dz ave mag Std dev RMS (absolute) (relative) Ave Dz 17mm, RMSE 20mm, STDev 6mm

18 Data Comparison Elevation Comparison to 2010 and 2013 control data Elevation Check 2010 Topeye Laser data to 2013 control Site Number of ave dz min dz max ave mag Std dev RMS control points dz (absolute) (relative) Ave Dz 15mm, RMSE 17mm, STDev 7mm

19 Data Comparison - Plan Plan Check Road Markings Resurfacing meant some control points not usable 2013 Lynx data to 2010 Control Total number of comparison points 364 Mean horizontal error (mm) -6.0 Minimum horizontal error (mm) -91 Maximum horizontal error (mm) 127 Sum of squares Horizontal RMSE (mm) Horizontal STDev (mm) Average Dxy 6mm. RMSE 34mm, STDev 34mm

20 Data Comparison - Plan Plan Check 2010 Ortho Imagery to 2013 Control Road Markings Total number of comparison points 191 Mean horizontal error (mm) 5.6 Minimum horizontal error (mm) -157 Maximum horizontal error (mm) 180 Sum of squares Horizontal RMSE (mm) Horizontal STDev (mm) Average Dxy 5.6mm. RMSE 47mm, STDev 47mm Accuracies confirm both datasets comparable with one another in both height and plan

21 Combining Datasets Considerations Laser coverage from each sensor Point density from each sensor Trajectory format and numbering Point classification Intensity range of each sensor Data volumes Nature of dataset Highway Urban Potential uses of combined dataset

22 Combining Datasets Slopes Lynx ground coverage affected by angles of adjacent cuttings and embankments Proximity of sensor to edge of slope effects data coverage

23 Combining Datasets Structures and Fences increase shadowing effect 70cm high fence, increases shadow x2.5

24 Combining Datasets Cutting Similar Shadowing effect Ideally vehicle should drive as close to top or bottom of slope as possible Or have the sensor as high as possible

25 Combining Datasets Slopes Lynx only data, difficult to confirm if lowest hits are ground Combining with Airborne data confirms ground location

26 Data Coverage All Points

27 Data Coverage Mobile Ground class

28 Data Coverage Mobile Carriageway Data

29 Combining Datasets Intensity Values Different Sensors and Manufacturers use different ranges Need to scale one to match other Lynx Intensity range Topeye Intensity Range Could scale Topeye values by 10 to match Lynx values or create a colour range to accountant for both scanners

30 Combined Datasets Methodology Ensure all trajectories in same time format Adjust project for increased point density

31 Combined Datasets Methodology Ensure all trajectories in same time format Adjust project for increased point density Airborne Data Remove points on carriageway

32 Combined Datasets Methodology Ensure all trajectories in same time format Adjust project for increased point density Airborne Data Remove points on carriageway Mobile data use all points

33 Combined Datasets Methodology Ensure all trajectories in same time format Adjust project for increased point density Airborne Data Remove points on carriageway Mobile data use all points Import both datasets into project

34 Combined Datasets Structures Bridge Topeye Data Lynx Data

35 Combined Data Combined Datasets Structures Bridge Topeye Data Lynx Data

36 Combined Datasets Structures - Tunnel

37 Summary Mobile and Rotary wing datasets do complement one another Infill data voids for each sensor Compatible data suitable for combining Data preparation essential Use all Mobile data Use Rotary Wing data outside carriageway BUT Need to justify additional capture cost Mobile capture cheaper, but resulting data is limited to the carriageway Rotary wing capture expensive, but wider coverage at a lower density Will someone be willing to pay for both?

38 Finally Thank You Any Questions or Comments?