RANGE FINDING DEVICE FOR PASSIVE AUTOMATIC FOCUSING DEVICE

摘要

PURPOSE:To offer the range finding device for the automatic focusing device which can measures the distance to a subject speedily with high accuracy so that secure focusing is possible even when there are plural subjects. CONSTITUTION:The subject is acquired by the photodetection sensors 10-30 consisting of three line sensors 10b-30b and zero-cross points of secondary differences of their brightness distributions are calculated and detected; while one of the zero-cross behavior data regarding the three line sensors 10b-30b is regarded as reference zero-cross behavior, other two behavior data are properly shifted to detect the coincidence point among the three zero-cross behavior data and the distance to the subject is calculated from the quantity of deviation between the zero-cross behavior data of the two line sensors at the time of the coincidence.