Research On Unwrapping And Stitching Technology Of Cannon Panoramic Image

The internal surface quality of the cannon is an important detection index to measure the processing quality of the cannon and the maintenance quality after use.In recent years,the panoramic imaging system with a large field of view and high resolution is widely used in various fields,but in the quality inspection of the internal surface of the cannon and gun,the method of capturing the image of its internal surface by the panoramic imaging technology is rare at home.The internal surface of the cannon is taken as the research object,the panoramic endoscope system of the cannon based on the principle of the cone mirror catadioptric panoramic imaging is designed,the object points on the internal surface of the 360° cannon is imaged without scanning by this system at once,a high resolution full cannon image is obtained by the unwrapping and stitching technology of the panoramic image.The main tasks include:(1)According to the requirements of the army's cannon endoscope,a panoramic endoscope system of the cannon with the intelligent correction is designed,including the optical imaging system of the endoscopic device,the embedded system and the correction system.A calculation method for the parameters of the non-single viewpoint cone mirror catadioptric panoramic imaging system of the endoscopic device is established,in order to capture the high-quality cannon panoramic image;adding the embedded system and the correction system is to achieve the position detection and automatic correction of motion deviation of the endoscope device respectively.(2)Aiming at the problem of the severe distortion of the panoramic image,a panoramic image unwrapping method based on the precise interpolation of the bi-directional projection model of the cone is proposed.A forward and backward bi-directional projection model of the cone is established,the coordinate mapping relationship between the corresponding pixels of the panoramic image and the unwrapping image is deduced,the pixels of the panoramic image are reversely mapped into the unwrapping image,the missing pixels in the unwrapping image are forward mapped into the original panoramic image,its neighborhood pixels are determined,the gray value of missing pixels is accurately restored by bilinear interpolation with error compensation.The method of combining the eight-quadrant symmetric multiplexing and the look-up tables is used to optimize the unwrapping algorithm to increase operating speed.(3)Aiming at the situation that the cannon image has few feature points and the two unwrapping images to be stitched have significant horizontal and vertical offsets,an image registration method based on offset detection is proposed.The centroid positioning method is used to detect the deviation of the reticle image captured by the correction system,in order to achieve horizontal registration of the images to be stitched by correcting the endoscopic device,the laser distance measuring principle is used to obtain the position information of the endoscope device,in order to achieve vertical registration of the image to be stitched.The method of fading in and out is used to fuse the registered images to eliminate gaps.The effectiveness of the unwrapping and stitching algorithm is verified by the simulation analysis and experimental tests.The experimental results show: the positioning accuracy of the bi-directional projection model of the cone is sub-pixel level,the algorithm in this paper is compared with the concentric circle approximate unwrapping method,the image information entropy is increased by 5.8%?6.2%,the average gradient is increased by 29.4%?33.1%,optimized unwrapping algorithm operating speed is increased by 4 times;the rifling matching degree is higher in the stitched full cannon image,the shape information of the internal surface of the cannon can be reflected in high resolution.The application of full cannon image in the quality inspection of the cannon not only achieves high-efficiency and high-precision detection without dead angle,but also saves a lot of manpower and material resources,which has important research value.