Distance Calculation from Single Optical Image

Abstract

Accurate and fast distance calculation with respect to a single optical image is useful for real-time 3D construction and acquisition, however currently rare distance calculation methods theoretically base on an optical single image, and the traditional distance calculation method with a single image has limitations due to assumption that the step edge in the image must be strictly horizontal or vertical, which is difficult to fulfill in real applications because the slope of a practical edge could be any other value except for zero and infinity. In this paper, a distance calculation method with a single defocused image containing an oblique step edge is proposed, and no special camera equipment or unique external condition is required. First, the basic theory of coordinate system rotation has been introduced to simplify the sampling process of neighbor points and eliminate the influence resulted from slope of the step edge; one-dimension point-spread-function of the original distance calculation method is expended to two-dimension, taking into account coordinate transform, and a comprehensive distance calculation based on an oblique step edge with any slope is deduced; The relationship between the precision of distance calculation and the slope of the step edge is analyzed and proved in theory. Finally, a serial of simulation are conducted to validate our proposed distance calculation method, and the experimental results prove the applicability, validity and high precision of our method.