A method of distance measurement by using monocular camera

We propose a method to measure the distance to the surface with any figures. The method uses two images, one is taken at a camera point and the other is taken at the point where the camera is moved along the optical axis. The distance is calculated from the ratio between each size of an object projected on two images. From the fact that the pair of images has concentric circle features, the ratio is obtained by using complex-log mapping. This method can calculate the distance to the surface with texture features or not.