The cannon chamber detection is an important task in the gun bore maintenance process, and it has direct relationship with the firing accuracy and security. The features of cannon chamber images obtained from grin lens array are analyzed, and an algorithm based on the phase-correlation and log polar is presented, which can realize mosaic image fast and seamlessly. Phase correlation algorithm can only match the images with shift invariability, and would face difficulty when dealing with motion model，where either scaling or rotation of the matched images is presented. Log-polarimage transform can convert the scale and rotation changes in Descartes coordinate to shift changes in log-polar coordinate. This method calculates the normalized peak of phase correlation of cross-power spectrum, and gets the rotation and scale between the two conjoint images using the peak coordination. Images are matched based on these parameters, and then chamber panoramic images are obtained by using method of pixels maximum value. Experimental results show that the proposed method can get seamless, clear and full image of gun bore.