[Apparent size of stereoscopic images with disparity in relation to the function of accommodation].

PURPOSE

We investigated experimentally the relationship between the apparent size of stereoscopic images with disparity and the accommodative function.

METHODS

The judgement of the apparent stereoscopic image size used the subject reply. The size of the forward image, which was produced by crossed visual lines with binocular disparity and by a time-sharing type stereoscopic three-dimensional display using liquid crystal shutter glasses, was compared with the size of the plane image. The size of the backward image produced by uncrossed visual lines was also compared with the size of the plane image. Sixteen normal volunteers were requested to subjectively compare each image with the original plane image on the display screen in relation to its size. Accommodation was measured using an infrared optometer to record the step responses (from far to near, and near to far). The subjects were divided into two groups, a fast response group and slow response group.

RESULTS

It was found that the forward image was smaller than the plane image and the backward image was larger than the plane image, and this tendency was remarkable in the fast response group.

CONCLUSION

From these results, it appears that the state of accommodation affects the perceived size of stereoscopic images with disparity.