基于LUT实时图像矫正的行缓存优化  

Line Buffer Reduction for LUT-Based Real-Time Image Rectification

作　　者：卢宇峰[1] 罗小华[1] 俞淼[1] 李益航[1] 

机构地区：[1]浙江大学超大规模集成电路研究所,杭州310027

出　　处：《复旦学报（自然科学版）》2016年第4期418-424,共7页Journal of Fudan University：Natural Science

基　　金：浙江省自然科学基金(LY15F040001)

摘　　要：基于反向映射的图像矫正被广泛应用于解决光学镜头透视引起的非线性畸变失真问题,该方法将映射坐标固化在LUT内,避免了复杂的坐标计算,但需要大量行缓存储备图像数据用以执行反向映射.为了减少行缓存的使用,本文提出了一种基于读扩展的环形行缓存读写算法,利用行同步信号的消隐间隔扩展读周期,使读写指针循序错开,保证上下映射的空间.相比传统的以最大偏移作为行缓存的结构,改进的专用控制算法可以减少近一半的内存使用.本文中的实时图像矫正系统已经在FPGA上实现,实验结果表明所提出的读扩展行缓存算法显著地改善了内存的消耗,并且获得良好的实时图像矫正效果.Inverse warping is widely adopted to rectify the image with non-linear distortion, which is caused by the perspective feature of optical lens. This scheme stores warping coordinates into look-up table （LUT） to avoid complex coordinates calculation, but requires large amounts of line buffer to place image date to perform inverse warping. To reduce the line buffer usage, this paper presents a line buffer algorithm basing on reading extended, which utilizes the horizontal banking to extend the reading period. The algorithm guarantees the write and read pointers dynamical jumping to provide the space for up and down mapping. The dedicated control scheme can reduce nearly half of the memory usage in contrast to a general circular buffer of maximum offset. The image rectification module has been implemented on a FPGA to remove lens distortions in real time. The experimental results prove that the proposed line buffer algorithm is highly effective in both memory reduction and distortion rectification.

关 键 词：LUT FPGA 图像反向映射 行缓存 实时 图像矫正 畸变失真 

分 类 号：TN79[电子电信—电路与系统]