4.6.6 Stereo reconstruction good practices

The parameters -bm.minhoffset and -bm.maxhoffset are used inside the application to derive the minimum and maximum horizontal disparity exploration, so they have a critical impact on computation time. It is advised to choose an elevation source that is not too far from the DSM you want to produce (for instance, an SRTM elevation model). Therefore, the altitude from your elevation source will be already taken into account in the epipolar geometry and the disparities will reveal the elevation offsets (such as buildings). It allows you to use a smaller exploration range along the elevation axis, causing a smaller exploration along horizontal disparities and faster computation.

-stereorect.fwdgridstep and -stereorect.invgridssrate have also a deep impact in time consumption, thus they have to be carefully chosen in case of large image processing.

To reduce time consumption it would be useful to crop all sensor images to the same extent. The easiest way to do that is to choose an image as reference, and then apply ExtractROI application on the other sensor images using the fit mode -mode.fit option.