Correction of capsule endoscope image distortion based on two-dimensional look-up table

Abstract

As the capsule endoscope lens will produce geometric distortion, while there is an angle and a corner between the camera image plane and the plane of scene, so the images of capsule endoscope get nonlinear geometric distortion. Before the capsule endoscope images are used to accurately analysis, we should eliminate these distortions. Typically, the correction uses a calibration pattern, which can be a chess board, dot, grid, or circle pattern. Based on this pattern, enough characteristic samples can be extracted accurately and conveniently, and mathematic model can be built for the distortion in the captured image with respect to the original calibration pattern. However, those methods are a kind of correction method using nonlinear function in all. For the case of local distortion situations, it is difficult to achieve the desired correction. This paper presents an image distortion correction method based on look-up table method. The method is to process image into blocks, making the pixels of the region on the image corrected. The experimental results show that: this method is reliable and effective.