Stereo photogrammetry#
Work in progress
Placeholder content. Being rewritten with figures.
Two views of the same patch of ground from different angles produce parallax — a pixel shift between images that encodes ground height.
What ASP actually computes#
For every pixel in the left image, ASP finds its match in the right image; the resulting disparity vectors plus the camera models triangulate to 3D ground coordinates.
Knobs that matter#
The matcher (--stereo-algorithm) and the subpixel refiner (--subpixel-mode) are the two parameters that most affect quality and runtime.
Geometry that matters#
Convergence angle and base-to-height ratio set the height precision achievable; both come from the satellite metadata and you can plot them with asp_plot.stereo_geometry.StereoGeometryPlotter.
Where matching fails#
Featureless terrain, repetitive textures, occlusion, and strong illumination differences all break the matcher; run-GoodPixelMap.tif flags where matching succeeded.