Investiations on depth perception in indirect vision

Abstract

The main results of the investigations on the visual space perception described in this paper may be summed up as follows : 1/ A relation exists between the monocular and the binocular depth perception in indirect vision. This relation can be formulated in the following way. The depth perception of the double images in binocular vision is principally the same as that of monocular images seen indirectly. The differences in depth perception are related to the changes of accommodation of the eye /eyes/ which cause changes in the shape, size, and distinctness of the retinal images to which also the depth perception is related. 2/ The depth perception in indirect vision varies with the wavelength of light used and therefore with the refractive index of light in the media of the eye, in monocular as well as binocular vision in such a way that with the increasing wavelength of light used the seen distance of the object decreases. However, when the colour filters are used the conditions of vision are much more complicated on account of various changes occurring in the field of vision due to eye rivalry, colour mixture, eye dominance, differences between the eyes, etc.; nevertheless here also there seems to exist a relation between the depth perception and the changes in the distinctness of the double and monocular images caused by the changes in the accommodation. In this case also the similarity between the monocular and double images exists. But some differences were observed due to the causes mentioned above. In the case of double images more frequent changes /inversions etc./ were observed making the images lesb steady than with the monocular vision. 3/ The relation between the angular positions of objects viewed monocularly and the depth perception of stereoscopic and single binocular images was established. 4/ The depth perception of the stereoscopic images is much more stable than that of the double and monocular images, and the changes in the distinctness do not play such an important part in this case. The inversions and the so called illusions are rare in stereoscopic images. 5/ The depth perception of stereoscopic and single binocular images is connected with the changes of convergence which cause the changes in the -angular distances of the images viewed monocularly.