Evaluation of observers´ sensitivity to lens distortion discrepancies in stereoscopic moving pictures

One potential factor of distorted stereoscopic perception of a 3D movie may be slightly different lens aberrations between the two lenses of the stereoscopic camera. We considered typical lens distortions discrepancies of several stereoscopic camera types ranging from cine to small action cameras. The determination of a detection threshold of different groups of observers with respect to gender, stereoscopic ability, media affinity, etc. was a main research topic. In one of our subjective assessments we used a gaze tracking system by which the eye movement of the observers could be roughly determined. We found out that image texture and content-driven gaze sequence had a strong impact on observer´s detection of stereoscopic aberrations. Minimal lens distortion discrepancy was already detected by at least 15.4% of the participants. The number of irritation statements increased with the magnitude of discrepancy. Observers showed highest sensitivity in still images or smooth camera travelling presenting many simple geometric objects. Still, up to 29% of the participants seemed to be quite immune against lens distortion discrepancies in spite of good stereo acuity as proven in Randot Stereo Vision test.