The images are in directory /honig/stereos in files earth.l.gif, earth.r.gif (stereopair), and earth.gif (raw data).
The images began as a 720 x 360 file of floating point elevations for the planet (found on hanauma.stanford.edu). Honig converted these to bytes to obtain a range image, a greyscale image. He used the 'rawtopgm' program to convert a headerless byte-file into .pgm format that can be read by his viewing program. View the images stereoscopically by running two copies of the viewing program (he uses 'xv').
Honig fed the range image and the elevation data to a program that added disparity info to the image. The disparity could be added by shifting the actual texture (the range image); or by superimposing a texture and shifting that. Various textures could be used.
(Honig used a texture with no pixel-by-pixel correlation. This was simple and yielded the smallest 'grain'. Several issues arise: should one use a constant-amplitude speckle noise, or should the noise amplitude vary with the pixel level (like quantum noise)? The problem here is that a constant amplitude will be large for dark pixels and unnoticable for bright pixels. Also, the dark pixels aren't seen. Using a scheme where speckle is added to small-valued pixels and speckle is subtracted from high-value pixels yields a form of gain control. This attentuates edges that are useful for stereo.)
Each method for adding disparity has its disadvantages. The problem with adding textures is that they degrade the greyscale image; the problem with shifting the images is filling in the resulting gaps, and a possible lack of features to match up for correspondence.
The images here have a pixel-disparity for every 250 meters of elevation difference. The noise has value -40, 0, or 40 greylevels.
It takes quite a while to achieve stereopsis for these images, but it can be done. The ocean floors and midoceanic ridges are particularly good. (Most of the relief of the earth is in the oceans.) The himalayas are probably too extreme to be fused, other ranges can be seen in depth.
The white artifacts are in the original data set.
Entry_ID: EARTH_LAND_UCI_STEREO_FTP1 (MD Identifier: 4237)
Geographic Coverage:
Southwest Extent: 90S,180W Northeast Extent: 90N,180E
Source:
SATELLITE
Storage Media:
on-line FTP
Discipline, Subdiscipline:
EARTH SCIENCE > LAND
Location Keyword:
GLOBAL
Parameter Group, Parameter:
BIOLOGICAL ENTITIES > SURFACE VEGETATION
GEODYNAMIC FEATURES > STRUCTURES
GEODYNAMIC FEATURES > TERRAIN ELEVATION
GEODYNAMIC FEATURES > VOLCANOES
GEOGRAPHY AND LAND COVER > CULTURAL FEATURES
GEOGRAPHY AND LAND COVER > ELEVATION
GEOGRAPHY AND LAND COVER > GLACIERS
GEOGRAPHY AND LAND COVER > LAKES
GEOGRAPHY AND LAND COVER > LANDFORMS
GEOGRAPHY AND LAND COVER > RIVERS
GEOGRAPHY AND LAND COVER > SURFACE VEGETATION
GEOGRAPHY AND LAND COVER > SURFACE WATER
GEOGRAPHY AND LAND COVER > TOPOGRAPHIC DATA
GEOGRAPHY AND LAND COVER > WETLANDS
HYDROLOGIC PARAMETERS > GLACIERS
HYDROLOGIC PARAMETERS > RIVERS
HYDROLOGIC PARAMETERS > SURFACE WATER
HYDROLOGIC PARAMETERS > WETLANDS
General Keywords:
CARTOGRAPHY
FTP
GEOGRAPHY
GEOLOGY
IRVINE
LAND COVER
LAND USE
MAPS
PHOTOGRAPHY
SATELLITE
STEREO
STEREO IMAGES
STEREO PHOTOS
TOPOGRAPHY
UCI
VEGETATION
Science Review Date: 1994-01-11
Revision Date: 1994-01-11
Archive:
UCI/FTP>U. of California, Irvine FTP site
Contact: HONIG, DAVID
Electronic Mail: INTERNET> honig@ics.uci.edu
INTERNET> support@ics.uci.edu
Entry Author: SHOTLAND, LAWRENCE M.
Electronic Mail: INTERNET> LSHOTLAND@STX.COM
INTERNET> SHOTLAND@NSSDCA.GSFC.NASA.GOV
NSI/DECNET> NSSDCA::SHOTLAND
Phone: (301) 441-4198
Information in this entry provided by UCI/FTP
** No Bibliographic Reference Information supplied for this Entry **
***** No Supplementary Information available for this selection *****