Most of the photos from this sample:link_to_sample_on_dropbox are not detected as containing asymmetric circles calibration pattern. It can see only IMG_0565.jpg IMG_0566.jpg IMG_0568.jpg IMG_0569.jpg. Videos from the same device (iPad 3) and of the same calibration pattern are detected fine. So, I wonder, what am I doing wrong? Maybe it is because of EXIF signature generated by iOS devices? Maybe camera orientation, while taking photos, matters?