Research On Image Mosaic Correction Technology Of Multi-Channel Projection System

With the continuous development of virtual reality technology,multi-channel projection display technology had been widely discussed.The multi-channel projection CAVE system’s extremely realistic virtual world could fulfill the needs of an immersive virtual reality experience for numerous users at once and from various viewpoints.In view of the problems of geometric distortion,color difference and high brightness of overlapping areas in the projection displayed screen of each projector in the multi-channel projection CAVE system,geometric correction,color correction and edge brightness adjustment were carried out respectively.The main work contents were as follows:(1)Geometric correction: A geometric correction method for multi-projection images based on a new fusion method was proposed.According to the characteristics of the folding projection of the CAVE system,the affine transformation was performed on the folding projection area based on the perspective transformation.Due to the non-ideal planarity of the actual projection screen,the bi-cubic Bezier surface was used to carry out nonlinear geometric distortion on the whole image,and the bi-cubic Bezier surface was used to correct the local nonlinear geometric distortion area in the image,further improving the accuracy and application range of geometric correction.(2)Color correction: A color correction method for multi-projection images based on free-form deformation technology was proposed.In consideration of the interaction among the three channels of RGB color space R,G and B,the free-form deformation technology model based on the Bernstein function was used to describe the RGB three-dimensional space,and the conversion relationship between the color intensity value of the projection display image in the camera space and the corresponding ideal color intensity value was obtained,so as to distort the color of the projection image and improve the color correction effect.(3)Edge brightness adjustment: The edge brightness adjustment method of a multi-projection image based on the fusion function of the attenuation function and gamma correction was discussed.The gamma coefficient applicable to the experimental environment of this paper was obtained through experiments,and the brightness attenuation of the overlapping area of the projection display screen was realized,so that the brightness of the overlapping area and the non-overlapping area was consistent and the brightness of the overlapping area was smooth.The image mosaic correction technology of the multi-channel projection system described in this paper was applicable to the CAVE system.The projection image was corrected by software to save costs.The projection display images of all projectors had no geometric distortion,consistent colors,and the brightness of overlapping and non-overlapping areas was consistent and smooth.