lunar digital elevation model generation using chandrayaan ... · image and lunar atlas) at sac,...
TRANSCRIPT
Lunar Digital Elevation Model Generation
using Chandrayaan-1
Terrain Mapping Camera (TMC)
K. SURESH
HIGH RESOLUTION DATA PROCESSING DIVISION
SIGNAL AND IMAGE PROCESSING GROUP
Introduction
Prime objective of Terrain Mapping Camera (TMC)
High resolution 3D mapping of topographic features
Triplet Imaging (Fore, Aft and Nadir)
B/H Ratio is 1
DEM Generation Combinations
Nadir-Aft
Nadir-Fore
Fore-Aft
Nadir-Fore-Aft
Envisaged to generate Higher Level Products (DEM, Ortho Image and Lunar Atlas) at SAC, Payload Operations Center (POC)
Indigenously Designed and Developed Software Package called LDEM for Fully Automatic DEM and Ortho Image Generation
Functions of POC @ SAC
POC focuses on
Higher Levels of processing for the science data
Planning of payload operations
Performance assessment of the payload
Payload calibration and Data Preparation
POCs are co-located with the
Laboratory/offices of Instrument designers/PIs and
Support the required infrastructure for processing storage and network connection
TMC Viewing Geometry
FOV :across track : ± 5.7º
along track : ± 25º
Fore to Aft : 60.3s (56 pixels shift due to moon rotation)
Swath 20Km
Chandrayaan-1 TMC Triplet Imagery
FORE NADIR AFT
DEM Generation Options
DEM Generation Combinations
Nadir-Aft
Nadir-Fore
Fore-Aft
Nadir-Fore-Aft
DEM Posting
25 Meter – First Version
10 Meter – Second Version
5 Meter - Experimentation
DEM Generation Overview
Reference Data Sets
Clementine Equatorial, North and South Pole Mosaic
ULCN Points for Height Reference
LRO WAC Equatorial, North and South Pole
Mosaic
LRO LOLA Points for Height Reference
Input Data Sets
Level-1 Product (Radiometrically
corrected)
Orbit, Attitude and Time
Ancillary Information (LBR and SPM)
Output
Equatorial Data in Seleno graphic Coordinates
North and South Pole Data in Polar Stereographic Projection
Moon Spheroid Datum (Mean Radius 1738km)
DEM in 25m and 10m Postings
Ortho Image in 5m Resolution
Format
GeoTiff (Classic and BigTiff)
DEM Generation
Full Strip DEM and Ortho Image Generation (Length:600km to 1800km)
Overlap Computation
Overlap b/w Fore, Aft and Nadir using Physical Sensor Model.
Imaging Model
Precise mapping between image and ground using
Sensor parameters (focal plane geometry in terms of alignment angles),
Platform parameters (orbit and attitude of the spacecraft) and
Scene parameters (terrain related information like datum, elevation)
Lunar Control Point (LCP) Identification
Same Point Identification on Fore, Aft and Nadir with respect to Reference.
Normally 25 to 50 LCPs are identified for each orbit depending on the length of the pass/strip
Space Resection
LCPs are used in space resection model to derive the refinement parameters.
DEM Generation …
Hierarchical Image Matching (HIM)
Generating dense conjugate points across the images of TMC i.e. the Fore, Aft and Nadir. Nadir as Reference Image.
Space Intersection – Irregular DEM
Object space coordinates are computed for irregularly spaced conjugate points generated using HIM technique .
Regular DEM Generation
Constrained Interpolation
No Height Value (-20000)
Grid and Ortho Image Generation
Ortho Rectification of Nadir Image
LDEM Results Pre and Post (100km) are Shown Below…
Output Visualizations and DEM Comparisons
DEM and Ortho Image
Surface Reconstruction using 10m DEM
Filtering Height Values
DEM 2.5D View with Ortho Image
DEM 2.5D View with Ortho Image
DOP:15-12-2008 Imaging Orbit:437
25m Color Coded DEM
10m Color Coded DEM Difference
Color Coded DEM
Frequency
Height (-17.5m to 10m)
Difference DEM Histogram
25m Color Coded DEM
10m Color Coded DEM
DOP:15-12-2008 Imaging Orbit:437
Comparison of DEMs (25m,10m and 5m)
25m DEM 2.5D View
10m DEM 2.5D View 5m DEM
2.5D View
DEM and Ortho Image Evaluation
DEM Visualization 2.5D Anaglyph
DEM Visualization 2.5D Anaglyph
Thank You