By using a planar gridding target calibration points could be achieved,and the precision of these calibration points were improved through revising the distortion coefficients of lens according to the principle of cross ratio invariability.

In this paper, a definition of distortion parameters for measuring plane quadrilateral element distortion is given.

Auto determination of distortion parameters for correction of scanned book image;

Based on the distortion model in which the radial geometric distortion is considered as the chief factor,a general correcting method that is independent of interior parameters of the imaging system,is given and discussed in this paper via a detailed analysis of the factors which largely influence the accurate measurement of distortion parameters.

The paper present the robust way to find automatically correspondind points and the optimal object function of solving radial distortion parameters.

Temperature field distribution and thermal distortion of thin film coatings irradiated by CO_2 laser;

Thermal distortions of electro-optic crystal for high average power laser systems;

Using the Shack-Hartmann wavefront sensor,the thermal distortions of the different substrates,the single layer thin films with different thickness and the different optical thin films irradiated by CO_2 laser at 10.