基于CUDA核函数的多路视频图像拼接加速算法

Acceleration Algorithm of Multi-channel Video Image Stitching Based on CUDA Kernel Function

目前,通用机场数量飞速增长,远程塔台发展迅猛,多路视频实时拼接技术不断改进。视频拼接算法大部分是改进特征点提取算法、特征点匹配算法和图像融合算法,改进特征点提取算法使得提取特征点更准确,改进图像融合算法使得全景图上各路图像色彩一致并且消除拼接缝,最后使用图形处理器实现加速。基于图像拼接整体计算流程,从数学角度计算原始图像到全景图像像素坐标变换矩阵和像素值变换矩阵。视频拼接时,基于像素坐标变换矩阵和像素值变换矩阵,使用核函数计算原始图像的像素点经过矩阵变换后的坐标和像素值,设置核函数被调用时的线程配置,充分利用图形处理器的并行计算能力,实现图像拼接加速。实验结果表明,拼接8张1080*1920的图像耗时约22 ms。视频拼接的核心技术包括拉流、解码、拼接、编码传输,文章结尾对其中的拉流和解码技术给出了建议。

With the rapid growth of the number of general airports and the rapid development of remote towers,multi-channel real-time video stitching technology is constantly improved.Most of the video mosaic algorithms are based on the improvement of feature point extraction algorithm,feature point matching algorithm and image fusion algorithm.The improved feature point extraction algorithm makes the feature points more accurate.The improved image fusion algorithm makes the color of each image on the panorama consistent and eliminates the stitching seam.Finally,the GPU is used to accelerate the process.This paper focuses on the overall calculation process of image mosaic,from the mathematical point of view to calculate the pixel coordinate transformation matrix and pixel value transformation matrix from the original image to panoramic image.In video stitching,based on the pixel coordinate transformation matrix of pixel value transformation matrix,the kernel function is used to calculate the coordinates and pixel values after matrix transformation.Set the thread configuration when the kernel function is called.The parallel computing ability of the graphics processor is fully utilized to accelerate the image stitching.The experimental results show that the stitching time of 8-channel 1080*1920 videos is about 22 ms.The core technology of video stitching includes streaming,decoding,stitching,coding and transmission.At the end of the paper,some suggestions on streaming and decoding technology are put forward.