Stereo Calibration: Why does my rectification not work?

I've been using the stereo camera calibrator app for a while now and I only succeeded once in getting correctly computed rectified images with my camera set-up. Here are two examples of my one successful calibrated session and another failed calibration - the latter stands for all my other failed tries.

In both examples the two cameras are placed on a camera rig with a camera base of ca. 20-21 cm difference between each other. Both times the two cameras are almost parallel to each other (with almost no rotation).

Example 1 - Successful rectification: (with only 7 accepted stereo pairs!)

Example 2 - Failed rectification: (with 17 accepted stereo pairs!)

I can not find a reason for this error. Shouldn't the app be able to even rectify images from slightly rotated stereo cameras? The essential and fundamental matrix seem to be calculated wrongly in the 2nd example. Does anybody have a clue what is going on here? I would appreciate any kind of help.

Answer 1

[sen]

Dear Sir，what kind of “Checkerboard Pattern” do you use？ Have you carefully read the help of the "Stereo Calibration App" in matlab?