- The target recognition ability of the human visual system can be severely affected by vibration of the imaging system. Although vibration can be minimized by proper design, it is often the main limitation on visual perception despite the best attempts at stabilization. There are two types of image degradation caused by vibration of the camera. The first is the vibration of the line of sight (LOS), causing location changes of the scene in successive frames. The second degradation type is the blur induced in each frame of the sequence due to motion during the exposure. We investigate the relative effect of these two degradation sources on the human visual system recognition abilities by conducting a series of psychophysical experiments. These experiments show that object recognition and orientation recognition abilities may be affected more by the motion blur of each frame than by the oscillation of the scene. An important implication of these results on digital image sequence restoration algorithms is that under certain conditions, the main effort should be put toward motion deblurring rather than on the precise registration of the frames.