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Alos optical data processing

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Presentation on theme: "Alos optical data processing"— Presentation transcript:

1 Alos optical data processing
End of Stage Presentation Trainee: ARNAL Etienne Tutor: Mr COLIN Olivier

2 Presentation Outline Alos Product Descriptor (PRISM and AVNIR2)
Alos Image Processing (PRISM and AVNIR2) Digital Elevation Model 3D results ESRIN - ARNAL Etienne 31/03/2017

3 Alos Product Descriptor (1/5)
Data Image DEM 3D results Alos Product Descriptor (1/5) Realisation of a cqfd dictionary containing the fields of the Product Format Description of Prism and Avnir2. Allows to find quickly all fields of level: 1A = raw data extracted from the Level 0, 1B1 = with radiometric corrections, 1B2R = geo-referenced, 1B2G = geo-coded. ESRIN - ARNAL Etienne 31/03/2017

4 Alos Product Descriptor (2/5)
Data Image DEM 3D results Alos Product Descriptor (2/5) CQFD: binary data reader. FILE ; |_ VOL ; | |_ VolumeDescriptor ; | |_ FilePointer ; (3 to 9) | |_TextRecord ; |_ LED ; | |_ CommonFileDescriptor ; | |_ FileDescriptor ; | |_ SceneHeader ; | |_ Ancillary1 ; | |_ Ancillary2 ; | |_ Ancillary3 ; VOL LED IMG TRL SUP Tie Points in the data ESRIN - ARNAL Etienne 31/03/2017

5 Alos Product Descriptor (3/5)
Data Image DEM 3D results Alos Product Descriptor (3/5) CQFD: binary data reader. |_ IMG ; | |_ IMG1 ; (1 to 6) | | |_ CommonFileDescriptor ; | | |_ FileDescriptor ; | | |_ Line 1 ; | | |_ … | | |_ Line n ; |_ TRL ; | |_ CommonFileDescriptor ; | |_ FileDescriptor ; | |_ Trailer ; |_ SUP ; | |_ Ancillary ; VOL LED IMG TRL SUP Tie Points in the data ESRIN - ARNAL Etienne 31/03/2017

6 Alos Product Descriptor (4/5)
Data Image DEM 3D results Alos Product Descriptor (4/5) CQFD: binary data reader. |_ TiePoints ; | |_ Line 1 ; | | |_ Lat ; | | |_ Long ; | |_ … | |_ Line n ; VOL LED IMG TRL SUP Tie Points in the data (I,J) are pixel and line of corrected image (φ,λ) are degrees of latitude and longitude ESRIN - ARNAL Etienne 31/03/2017

7 Alos Product Descriptor (5/5)
Data Image DEM 3D results Alos Product Descriptor (5/5) Thanks to this CQFD dictionary, everybody can find a precise field in every Prism and Avnir2 data. The next step is to create image. ESRIN - ARNAL Etienne 31/03/2017

8 Alos Image Processing (1/5)
Data Image DEM 3D results Alos Image Processing (1/5) 3 various image data structure: Several CCD (Prism 1A, 1B1)  From 3 to 6 CCD  CCD = ~4992 pixels * lines  Overlap = 32 pixels One CCD (Prism 1B2R, 1B2G)  CCD = ~15000 pixels * lines 4 Spectral Bands (Avnir2)  Band = ~7150 pixels * 8000 lines ESRIN - ARNAL Etienne 31/03/2017

9 Alos Image Processing (2/5)
Data Image DEM 3D results Alos Image Processing (2/5) Imager: data reader for image generation For each pixel: elaborates from the band values (0 to 255) applying sun angle correction and stretching to enhance image contrast, extracts Tie Point (λ,φ) grid. It creates:  one image file (including all CCD/Bands),  one GeoTiff file (geolocalisation). ESRIN - ARNAL Etienne 31/03/2017

10 Alos Image Processing (3/5)
Data Image DEM 3D results Alos Image Processing (3/5) Prism Nadir 1B2R Shizuoka, Japan on February 14, 2006 ESRIN - ARNAL Etienne 31/03/2017

11 Alos Image Processing (4/5)
Data Image DEM 3D results Alos Image Processing (4/5) Avnir2 Tanegashima Is., Japan on February 17, 2006 ESRIN - ARNAL Etienne 31/03/2017

12 Alos Image Processing (5/5)
Data Image DEM 3D results Alos Image Processing (5/5) encountered problems  Avnir2, ±5 pixels between each columns.  Prism and Avnir2, geolocalisation error.  Prism, many artifacts.  Prism and Avnir 1B2(R/G), nothing about time in the data. Nadir Forward ESRIN - ARNAL Etienne 31/03/2017

13 Digital Elevation Model (1/10)
Data Image DEM 3D results Digital Elevation Model (1/10) Stereoscopy 3D, imager process. For each pixel [I,J], Find the value of pixel Nadir [I,J] and [λ,φ]=fN(I,J) Find the value of pixel Backward fB-1[λ,φ] Find the value of pixel Forward fF-1[λ,φ] Output: one RGB image with R=Nadir, G=Forward and B=Backward. ESRIN - ARNAL Etienne 31/03/2017

14 Digital Elevation Model (2/10)
Data Image DEM 3D results Digital Elevation Model (2/10) DEM, bases  Height is proportional to the along track displacement. Nadir Satellite track Forward ESRIN - ARNAL Etienne 31/03/2017

15 Digital Elevation Model (3/10)
Data Image DEM 3D results Digital Elevation Model (3/10) DEM, base equation ∆ is a multiple of the ground resolution ESRIN - ARNAL Etienne 31/03/2017

16 Digital Elevation Model (4/10)
Data Image DEM 3D results Digital Elevation Model (4/10) DEM Algorithm. Image adjustments Forward Nadir Backward Mean = 35 STD = Mean = 43 STD = Mean = 57 STD = ESRIN - ARNAL Etienne 31/03/2017

17 Digital Elevation Model (5/10)
Data Image DEM 3D results Digital Elevation Model (5/10) DEM Algorithm. Image adjustments, Generate pyramid image, with gradually degraded resolution. Pass the matched points to the higher resolution level for fine matching. ESRIN - ARNAL Etienne 31/03/2017

18 Digital Elevation Model (6/10)
Data Image DEM 3D results Digital Elevation Model (6/10) DEM Algorithm. Image rectification, Generate pyramid image, Feature matching, ESRIN - ARNAL Etienne 31/03/2017

19 Digital Elevation Model (7/10)
Data Image DEM 3D results Digital Elevation Model (7/10) DEM Algorithm. Image rectification, Generate pyramid image, Feature matching, Matching results, 1/16 1/8 1/4 1/1 1/2 ESRIN - ARNAL Etienne 31/03/2017

20 Digital Elevation Model (8/10)
Data Image DEM 3D results Digital Elevation Model (8/10) DEM Algorithm. Image rectification, Generate pyramid image, Feature matching, Matching results, Filtering. Median filter, reduce noise (peaks): Mean filter, reduce high frequencies: ESRIN - ARNAL Etienne 31/03/2017

21 Digital Elevation Model (9/10)
Data Image DEM 3D results Digital Elevation Model (9/10) Integration in eogrid.esrin.esa.int. Modification for Linux (no graphics), Installation of Matlab Component Runtime, Compilation of Matlab code (Stand-alone application). Integrated new “DEM” application in G-POD in < 1 day ESRIN - ARNAL Etienne 31/03/2017

22 ESRIN - ARNAL Etienne 31/03/2017

23 Digital Elevation Model (10/10)
Data Image DEM 3D results Digital Elevation Model (10/10) encountered problems Co-registration is corrected manually due to ALOS processors geo-referencing problem Result of matching requires validation of the correlation distribution  not trivial Correlation is impaired by high height gradients in image (e.g. buildings)  possible solution to weight the matching window with distance to centre Patterns oriented along-track have low correlation contrast Moving objects (cars, boats, troy horses, etc) Sun glint creates big differences between views Image radiometric quality (e.g. striping, spurious saturation artifacts) Image boundaries ESRIN - ARNAL Etienne 31/03/2017

24 3D results Japan, Shizuoka and surroundings , 02/14/2006.
Data Image DEM 3D results 3D results Japan, Shizuoka and surroundings , 02/14/2006. AATSR Hurricane Jeanne, 20/09/2004 Stereoscopic views. Digital Elevation models. ESRIN - ARNAL Etienne 31/03/2017

25 Potential Enhancements
Investigate alternative matching methods for high gradient terrains (e.g. parallax, urban areas) Make adaptive algorithm e.g. apply dynamically different techniques/parameters depending on correlation contrast observed Integrate automatic co-registration of the 3 views with a good geo-referencing. Add possibility to correlate several bands in parallel (e.g. AATSR dual views with 4 channels) Include DEM geo-coding in last stage Optimize algorithm for performance in multi-processing environment (e.g. tiling) Calibration & Validation ! ESRIN - ARNAL Etienne 31/03/2017

26 Thanks Data Image DEM 3D results Olivier Colin, Jerome Louis,
Philippe Goryl, Peter Reinartz (DLR), Nityaporn Sirikan, Patrick Grimont, Emmanuel Mathot. Questions ? ESRIN - ARNAL Etienne 31/03/2017


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