In this paper, we propose a method to measure the distance between the camera and object of the scene. In our method, first we calculate the distance between the camera and the scene, and then measure the depth of the objects of the scene. The measurement of depth needs some information from camera, so we use the two symmetric frames to calculate the parameters of camera. In the second step, to remove radial and lens distortion, third, to rectify the input images, finally, use the block-matching stereo algorithm and graph cut-based algorithm with SAD to find the disparity. When we finish the measurement of depth of the background in the video, we can use the information to implant the objects and adjust their size automatically.