Character texture enhancement of 3D animated keyframe images based on SIFT algorithm and LK optical flow

Abstract The keyframe image character of 3D animation refers to the image state of the character or scene and other objects presented at specific keyframes in the animation timeline. The character texture will be blurred, distorted and discontinuous in the animation sequence due to motion, perspective change or lighting difference. Due to the lack of optical flow information to guide the current 3D animation keyframe image enhancement process, it is difficult to effectively distinguish the foreground character from the background elements, which affects the algorithm’s ability of recognizing the animation character’s movement patterns. To this end, a character texture enhancement method based on the SIFT algorithm and LK (Lucas-Kanade) optical flow is investigated for 3D animation keyframe images. The SIFT algorithm is used to extract the feature points of the character in each frame of 3D animation image as the initial tracking template, the LK optical flow method is used to calculate the optical flow vector of the feature points in the new frame, and the weighted directional histogram is used to estimate the direction of the character’s movement, and then the feature points in the tracking template are optimized through feature matching and weight updating to complete the tracking of the character’s target in each frame of the image. According to the target tracking results, a fractional-order differential mask is constructed in the character target region, and an adaptive function is constructed by combining the modes of the local gradient, information entropy and variance parameters of the image, so as to realize the enhancement of the character texture of the key frame images of the 3D animation by dynamically adjusting the order of the fractional-order differential. The experimental results show that the method can realize the dynamic tracking of 3D animation image character, and the extracted 3D animation image character feature points show a balanced distribution, and the distribution ratio is reasonable. It can realize the texture enhancement of 3D animation keyframe images, and the enhanced animation character clothing, facial details and other information are clearly recognizable, so as to improve the overall quality and visual impact of 3D animation.