Abstract: Aiming at the problems of ghost and uneven brightness in parallax image stitching, this paper proposes a parallax image stitching algorithm based on grid motion statistics（GMS） and improved optimal seam. Firstly, the fast feature extraction and description（ORB） algorithm is used to extract feature points and the GMS algorithm is used to screen out the mismatched points. Then, HSV color space and image gradient difference are introduced to improve the energy function to avoid the stitching line passing through the image edge. Based on the graph cutting method, the optimal seam is obtained, and the gradient fusion stitching of the image is carried out. The simulation results show that, in the case of large disparity, compared with the algorithm based on scale feature invariance（SIFT） and the algorithm based on accelerated robustness feature（SURF）, the accuracy of feature point matching of this algorithm is increased by 2.01 times and 4.73 times at the lowest and highest, and the image naturalness is increased by 20.6% on average. Moreover, the stitched image has uniform brightness and no perspective distortion.

Key words: image processing, image stitching, grid-based motion statistics, graph-cut, optimal seam, gradient fusion