Image processing apparatus suitable for measuring depth of given point

Abstract

First and second images as stereoscopic images of an object are obtained. The second image is shifted by a value dx. Absolute values of differences between image data of the shifted image and the first image are calculated, thus obtaining a third image. The third image is subjected to average value filtering to obtain a fourth image. A fifth image which has the same size as that of the fourth image and has a maximum gray level in an initial state is prepared. Image data having a smaller value is selected from image data of the fourth and fifth images to obtain a sixth image. Absolute values of differences between image data of the sixth and fifth images are calculated, thus obtaining a seventh image having the calculated absolute values as image data. A ninth image which has the same size as that of the seventh image. When the gray level of the pixel of the sevength image is 0, an eighth image is obtained to have the image data of the ninth image. When the gray level of the pixel of the seventh image is other than 0, the eighth image is obtained to have image data representing a gray level corresponding the value dx as the image data. After the eighth image is obtained, the sixth image is set as the fifth image, the eighth image is set as the ninth image and value dx is updated, and the eighth image is repetitively obtained. The finally obtained eighth image is determined as a parallax image representing a deviation of positions of corresponding pixels on the first and second images by gray levels. Based on the parallax image, a to an arbitrary point with respect to a reference point is determined.