Presentation on theme: "September 2013, Fontainebleau, France"— Presentation transcript:
1 September 2013, Fontainebleau, France 13th International Scientific and Technical Conference From Imagery to Map: Digital Photogrammetric TechnologiesA Case Study of Pleiades Tri-Stereo Imagery:accuracy assessment, interpretability, 3D modeling potential.Elena Kobzeva, Chief Engineer, Technology 2000Nadezhda Malyavina, Head of Racurs Production departmentPetr Titarov, Software developer, RacursSeptember 2013, Fontainebleau, France
2 A Case Study of Pleiades Tri-Stereo Imagery ContentsPleiades imagery orientation accuracy assessment3D modeling of urban area (the city of Yekaterinburg)Creating and updating topographic maps using Pleiades imagery
3 Pleiades imagery orientation accuracy assessment Pushbroom imagery orientation modelsTest dataset descriptionPleiades imagery orientation accuracyRigorous, rational polynomial (RPC) and universal pushbroom modelsPleiades Tri-Stereo product and ground points setOrientation accuracy of single Pleiades images, stereopairs and the triplet
8 Universal pushbroom models Parallel-perspective modelDirect Linear Transformation (DLT)Affine model
9 Test dataset description Pleiades Tri-Stereo ImageryParametersImagesImage IDDS_PHR1A_ _ SE1_PX_E060N56_0920_01800DS_PHR1A_ _ SE1_PX_E060N56_0920_01876DS_PHR1A_ _ SE1_PX_E060N56_0920_01876Imaging date and time:19:53.4:20:16.6:20:27.4Viewing angle along track10.1°-2.7°-8.5°Viewing angle across track1.4 °1.9°2.1 °
11 Test dataset description Ground points setGround coordinates accuracy: m RMSEPoints measurements in the images accuracy: 1 pixel
12 Pleiades imagery orientation accuracy assessment: methodology Scheme #GCPsnumberOrientation modelObjectiveIRPCSupplied RPC accuracy assessmentIIRPC + shiftAssessment of accuracy achievable using supplied RPC and tie points (but no ground control)III1Assessment of accuracy achievable with RPC and a single ground control pointIV4RPC + affineAssessment of accuracy achievable with RPC and the typical ground control point configuration, applying affine refinementVTo compare the efficiency of affine and shift RPC refinementsVI10To find out if the accuracy improves with increasing the number of ground control points in the case of applying shift RPC refinementVIITo find out if the accuracy improves with increasing the number of ground control points in the case of applying affine RPC refinementVIIIall availableAssessment of the best achievable accuracy in the case of applying shift RPC refinementIXAssessment of the best achievable accuracy in the case of applying affine RPC refinementXAffineAssessment of accuracy achievable with the affine universal model and a minimal set of ground control points, and comparison with orientation with RPC (the ground control points set was the same as in Schemes III and IV).XIParallel-perspectiveAssessment of accuracy achievable with the various universal models and comparison with orientation with RPC (the ground control points set was the same as in Schemes V and VI).XIIDLTXIII
16 Pleiades imagery orientation accuracy: single images Conclusions:Planimetric accuracy of supplied RPC was RMSE m (the specification is CE90 = 8.5 m).The accuracy of m RMSE (i.e. rather close to the limit set by the measurements accuracy) was achieved with a single GCP, applying shift refinement to the supplied RPC model.The accuracy of m RMSE was achieved with 4 GCPs, applying either shift of affine RPC refinement.Further increasing the number of GCPs did not improve the accuracy.The orientation accuracy achieved with universal methods varied over a wide range and was significantly worse than one achieved with RPC and bias removal.
17 Pleiades imagery orientation accuracy: the triplet Triplet orientation without tie pointsSchemeGCPs countOrient. modelGCP RMSE, mGCP MAX, mCPs countCP RMSE, mCP MAX, mdSdZIRPC-318.104.22.168III1RPC+shift0.0322.214.171.124.3IV4RPC+aff.0.1342.04.3V0.31.60.52.10.71.54.4VI126.96.36.199.528VIIRPC+affine1.02.72.41.85.0VIII5.9IX1.26.1Xaffine13.551.436.9125.6XIpar.persp.11.55.523.73.413.77.334.3XIIDLT0.93.11.919.149.3XIII10.35.121.43.5188.8.131.52
18 Pleiades imagery orientation accuracy: the triplet Triplet orientation with tie pointsSchemeGCPs countOrient. modelGCP RMSE, mGCP MAX, mCPs countCP RMSE, mCP MAX, mdSdZIIRPC+shift-3184.108.40.206.7III10.20.63220.127.116.11IV4RPC+affine0.1340.82.04.3V0.31.60.52.11.54.7VI101.12.4282.35.4VII5.2VIII1.25.0IXXaffine0.08.038.019.367.8XIpar.persp.28.79.564.231.912.695.2XIIDLT30.57.467.334.611.1106.2XIII30.970.533.813.6105.8
19 Pleiades imagery orientation accuracy: the triplet Conclusions:Using supplied RPC and no GCPs, the achieved planimetric accuracy was 3.6 m RMSE in the case of involving tie points and 3.8 m without them; the vertical accuracy was 2.2 m in both cases. So involving tie points in the adjustment procedure did not significantly improve the accuracy;Involving GCPs made the difference between adjustment with and without tie points insignificant.The accuracy of m RMSE was achieved with 4 GCPs, applying either shift of affine RPC refinement. Using a single GCP and applying shift RPC refinement, the planimetric accuracy of m and the vertical accuracy of m were achieved. Increasing GCPs number to 4 allowed improving the results but not significantly, the vertical accuracy became of m.Further increasing the number of GCPs did not improve the accuracy.The universal methods are not suitable for stereoscopic (three dimensional) processing of Pleiades imagery.
22 Pleiades imagery orientation accuracy: stereopairs vs. the triplet Forward + nadir stereopair orientation (B:H=0.25)SchemeGCPs countOrient. modelGCP RMSE, mGCP MAX, mCPs countCP RMSE, mCP MAX, mdSdZIRPC-253.32.64.27.7III1RPC+shift0.0240.82.81.47.8IV4RPC+ affine0.618.104.22.168.4V0.41.60.52.51.36.3VI101.51.02.4152.76.7VII6.5
23 Pleiades imagery orientation accuracy: stereopairs vs. the triplet Nadir + backward stereopair orientation (B:H=0.11)SchemeGCPs countOrient. modelGCP RMSE, mGCP MAX, mCPs countCP RMSE, mCP MAX, mdSdZIRPC-254.13.54.99.4III1RPC+shift0.0241.03.01.78.0IV4RPC+ affine0.21.80.32.522.214.171.1240.1V0.42.70.64.03.31.28.8VI102.44.6151.4VII0.52.24.32.97.8
24 Pleiades imagery orientation accuracy: stereopairs vs. the triplet Conclusions:The accuracy of orientation of the triplet and of the forward+backward stereopair (i.e. the stereopair with the largest base-to-height ratio) was approximately the same.The accuracy of triplet orientation was slightly better than one of the stereopairs which included the nadir image (so the stereopairs had lower base-to-height ratio).
25 Mapping and 3D modeling of urban areas Creating 3D modelsDeriving DEMGenerating orthoimagery3D modeling of urban areaAssessment of suitability for topographic maps creating and updatingInterpretability assessmentAssessment of objects positioning accuracyDrawing contour lines
26 Creating 3D models using PHOTOMOD: deriving DEM
27 Creating 3D models using PHOTOMOD: generating orthoimagery
28 Creating 3D models using PHOTOMOD: 3D vectorization
29 Creating 3D models using PHOTOMOD: automatic 3D modeling
36 Assessment of objects positioning accuracy Source dataset:Pleiades stereopair (9º and -11º), 0,5 m, PANPleiades orthoimagery 0.5m, RGBWV2 orthoimagery, 0.5m, RGBA3 orthoimagery 0.1m, RGB as reference data
37 PHOTOMOD. Comparing different types of objects Single-storey private housesMultistory city buildingsPleiades A3Pleiades A3
38 Interpretability analysis It is impossible to tell residential buildings from nonresidential ones1.5 m - wide ledges are indiscernibleShape and size of multistory buildings are reconstructed correctlySome architectural forms may be missing (the ledges areshown on one side of the building and missing on the other)
39 Assessment of objects positioning accuracy ParameterWV2 orthoPleiades orthoPleiades stereoNumber of measurements371366Mean error, m126.96.36.199Maximum error, m4.05.43.5Error distribution – vector map of scale 1: 2 000Error distribution – vector map of scale 1 : 5 0000-0,4 mmmmlarger than 0.8 mm0-0,4 mmmmlarger than 0.8 mm
41 Contour lines verification using reference data Vector topographic maps of scale 1:10 000,contour interval 2 mContour lines derived from the Pleiades stereopair
42 Topographic mapping and 3D modeling of urban areas Conclusions:The 3D model created is geometrically accurate and discrete, so it is possible to access separate objects, to set attribute values for them and to perform 3D measurements - in other words, to produce geospatial databases. The model can be used for visualization and for 3D city planning. Stereoscopic measurements ensure better accuracy and interpretability than ones performed in single images, while using tri-stereo imagery reduces “blind zones”.Pleiades images are suitable for creating and updating topographic maps of scale up to 1: If additional sources of data are available and field verification is possible, it is possible to create and update 1 : scale maps of moderate-sized inter-settlement areas.Accuracy and interpretability of Pleiades imagery are comparable to ones of WordView-2.
43 RACURS and TECHNOLOGY 2000 ASTRIUM GeoInformation Services AcknowledgementRACURS and TECHNOLOGY 2000express their gratitude toASTRIUM GeoInformation Servicesfor the Pleiades Tri-Stereo Imagery Productover the city of Yekaterinburg
44 A Case Study of Pleiades Tri-Stereo Imagery Thank you for attention !