Analysis of the Pulfrich Effect

Abstract

An object swinging horizontally in a frontoparallel plane appears to move in an elliptical orbit in depth when it is observed with a neutral density filter over one eye. This phenomenon is called the Pulfrich effect. In this paper, the amount of the depth was measured as a function of pattern velocity and filter density by giving the patten a binocular disparity that cancelled the apparent depth. The magnitude of time delay given by each filter was derived from the experimental results. The apparent orbit due to a simple harmonic motion was also synthesized from the results.