In this paper, according to the characteristics of central projection, aerial photographs were analyzed to discuss displacement of images under tilt conditin or caused by ground undulation, based on which the principles of tilt error and projection error were summarized.

Based on the analysis of Kruppas theorem and geometric methods sufficient and necessary conditions that figure Φ is a central projection of the space affine coordinate system are put forward in this paper.

Analysis and selection of the examination target of investigation center;

This paper proposes an iterative golden section search method based on reconstructed slices evaluation of a string to achieve precise projection center,as well as detector s rotate/tilt angle and distance from x-ray spot to rotate center.

The privipal steps of constructing of diagram for perspective reversion are to find out the projection center and to locate the perspective axis at suitable position.