改进的联合去马赛克与放大算法及其硬件实现  

Improved joint demosaicking-zooming algorithm and its hardware design

作　　者：李华[1] 朱波[2,3] 

机构地区：[1]商洛学院,陕西商洛726000 [2]中国科学院西安光学精密机械研究所,陕西西安710119 [3]西安交通大学一西安光学精密机械研究所空间视觉联合实验室,陕西西安710049

出　　处：《光电子．激光》2014年第1期199-206,共8页Journal of Optoelectronics·Laser

基　　金：国家自然科学基金重点项目(90920301,61231018);陕西省教育厅科研计划(2013JK1057)资助项目

摘　　要：为了从单CCD/CMOS图像探测器相机拍摄的Bayer格式图像恢复出更高分辨率全彩色图像,设计了一种改进的联合去马赛克与放大算法。首先,估计原始Bayer格式图像中丢失的绿色通道信息,根据颜色梯度的比较结果,将水平或垂直方向的绿色通道信息作为彩色图像的G分量,并根据彩色图像颜色通道之间高度相关的特性,计算颜色差R-G和B-G;然后,将去马赛克过程中的梯度方法继续用于确定丢失的绿色像素,放大绿色通道;最后,对颜色差值图像R-G和B-G进行放大,即可恢复出红色和蓝色通道信息,得到放大的全彩色图像。试验结果表明,算法恢复出的高分辨率彩色图像的峰值信噪比(PSNR)有较明显提升,且主观目视清晰、边缘锐利,特别是硬件实现方面能够做到实时处理。目前,本文算法已经在Xilinx公司的FPGA上实现,并用于工程实践。满足了项目实际需要。In order to obtain higher resolution full color image from Bayer CFA structure image directly,this paper presents a new joint demosaicking and zooming algorithm for digital camera equipped with a single CCD/CMOS sensor.We firstly extract GH and GV components of each pixel from m osaicking image through horizontal and vertical interpolations,respectively,and then we calculate and compare the hori zontal chrominance gradient and the vertical one for choosing the missing G from GH and GV.By exploiting the hig h spectral-spatial correlations between color channels,we compute the two color difference images R-G and B-G to reduce the demosaicking and zooming errors.Next,we obtain the horizontal GzoomH and vertical G zoomV of each pixel,and also choose the missing zoomed Gzoom by calculating and comparing the chrominance gradient .Finally,the enlarged red and blue channels are obtained by adding the corresponding enlarged R-G and B-G color d ifference images to the enlarged green channel.Experimental results prove that the proposed algorithm outperfor ms some state-of-the-art demosaicking-zooming methods in both peak signal-to-noise ratio （PSNR） measur e and visual quality.Furthermore,computational cost of the algorithm is low and it can be hardware processed in real time.Now,the proposed a lgorithm is implemented on Xilinx FPGA and used in camera system,and the perfect restoration quality and ef fectiveness meet the requirement of system design.

关 键 词：Bayer格式图像 去马赛克 放大 FPGA 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]