Stereo matching for pushbroom stereo cameras
Herbert Jahn · elib (German Aerospace Center) · 2000
A parallel stereo matching algorithm is presented which is mainly thought for the processing of images from pushbroom stereo cameras. The algorithm is designed for non-epipolar geometry, because of disturbances of flight attitude and velocity. Existing epipolar algorithms can give a first estimation of disparities in epipolar (x-) direction, but the recursive algorithm can also start with zero-disparity initial condition if the disparities are not too big. The algorithm minimizes locally a certain least squares distance of a stereo image pair using the method of steepest descent leading to a recursive disparity updating. To diminish ambiguities a pyramid with Gaussian image smoothing together with other measures (e.g. exploiting the ordering constraint and applying edge preserving disparity smoothing) is used. The presented matching algorithm is parallel in space and sequential in time. Therefore, when suitable parallel processing hardware (with one processing element assigned to each pixel) will be available then real-time stereo processing becomes possible. Some examples demonstrate the capabilities of the algorithm but also the remaining difficulties.