Images with severe geometrical distortions

which are induced by camera lens and position

must be corrected before extracting quantitative measurements.In this paper

we present a geometric calibration method for lens camera by applying polynomial warping and bilinear interpolation

and discusses the selection pattern of control points.First

we implement a general polynomial warping algorithm and a bilinear interpolation algorithm in Visual C++5.0

then we demonstrate that

for common optical lens

images with geometric distortions can be rectified with cubic polynomial warping method using only a few control points.This method is simple and practical

and can be used in camera-fixed situations

such as operating table and on-line industry inspection

to acquire lossless images. Practical application in lottery printing quality inspection shows that the method is reliable and valid.