In order to obtain high quality real-time full color image with a single image sensor coated with Bayer CFA
this paper researches and designs an improved real-time color image acquisition system based on FPGA. Firstly
design of MT9M011 sensor registers setting timing is introduced. And then
the paper pays key attention to demosaicking algorithm which is critical to the color image quality.The proposed demosaicking algorithm adopts the second-order Laplacian interpolation filter to the Bayer pattern image
and combines with chrominance and gradient for choosing the missing green samples.After the green channel has been reconstructed
we interpolate R and B as the average of the four nearest neighbors. By now
the full color image is reconstructed. Finally
GigE based image transmission is implemented to improve the image throughput. Experimental results proved that on average the improvement is 15 dB over the Bilinear Algorithm (BI) in PSNR and it produces visually more pleasant color images details with color artifacts greatly suppressed. Real-time 1 2801 024 resolution color image read-out could be achieved at speed 15 f/s. Now
the design is successfully used in our camera system
the perfect restoration quality and effectiveness meets the requirement of system design.
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references
Bayer B E.Color imaging array:US Patent, 3 971 065[P].1975-03-05.[2] 王暕来, 杨春玲. 基于最大类间方差法的图像分割系统的设计与实现[EB/OL].http://www.altera.com.cn/education/univ/local/events/articles/july08-3.pdf. Wang J L, Yang C L.Implementation of image segmentation system based on Otsu method[EB/OL].http://www.altera.com.cn/education/univ/local/events/articles/july08-3.pdf.[3] Henrique S M, He L W, Ross C. High-quality linear interpolation for demosaicing of bayer-patterned color images[C].IEEE International Conference on Acoustics, Quebec, Canada:Speech and Signal Processing:2004:485-488.[4] Adams J E, Hamilton J F.Adaptive color plane interpolation in single color electronic camera:US Patent, 5 506 619[P].1996-04-14.[5] Zhang L, Wu X L. Color demosaicking via directional linear minimum mean square-error estimation[J].IEEE Transactions on Image Processing, 2005, 14(12): 2167-2178.[6] Zhang L, Wu X L, Antoni B, et al. Color demosaicking by local directional interpolation and nonlocal adaptive thresholding[J].Journal of Electronic Imaging, 2011, 20(2):203016(1-16).[7] Daniele M, Stefano A, Giancarlo C. Demosaicing with directional filtering and a posteriori decision[J].IEEE Transactions on Image Processing, 2007, 16(1):132-141.[8] Zhang L, Dong W S, Wu X L, et al.Spatial-temporal color video reconstruction from noisy CFA sequence[J].IEEE Transactions on Circuits and Systems for Video Technology, 2010, 20(6):838-847.[9] 朱波, 汶德胜, 王飞, 等. 应用字典学习算法改善Bayer格式图像彩色恢复效果[J]. 电子与信息学报, 2013, 35(4): 8-16. Zhu B, Wen D S, Wang F, et al. Improvement of Bayer-pattern demosaicking with dictionary learning algorithm[J].Jounal of Electronics & Information Technology, 2013, 35(4): 8-16. (in Chinese)[10] 张传胜. 基于SOPC的通用液晶屏人机交互系统GUI的设计[J]. 液晶与显示, 2013, 28(2):250-254. Zhang C S.Design of man-machine interaction systems based on LCD screen of SOPC[J].Chinese Journal of Liquid Crystals and Displays, 2013, 28(2):250-254. (in Chinese)[11] 王静轩, 尹传历. 基于DSP和FPGA的嵌入式实时图像增强系统[J]. 液晶与显示, 2013, 28(3):459-463. Wang J X, Yin C L.Embedded color image enhancement system based on DSP and FPGA[J].Chinese Journal of Liquid Crystals and Displays, 2013, 28(3):459-463. (in Chinese)[12] Micron Inc.MT9M011 datasheet[OL].[2004-01-05].http://www.ic5.cn/p_MT9M011_nzw.html.[13] 朱波, 汶德胜, 王飞. 改进的Bayer插值算法及其硬件实现[J]. 光电子激光, 2013, 24(6): 1211-1218. Zhu B, Wen D S, Wang F.Improved bayer-pattern demosaicking and its hardware design[J].Journal of OptoelectronicsLaser, 2012, 24(6): 1211-1218. (in Chinese)[14] Kolta R W B, Aly H A, Fakhr W. A hybrid demosaicking algorithm using frequency domain and wavelet methods[C]//International Conference on Image Information Processing, 2011:1-6.