Lei Zhang Rastislav Lukac Xiaolin Wu David Zhang PCA-Based Spatially Adaptive Denoising of CFA Images for Single-Sensor Digital Cameras. 797-812 2009 18 IEEE Transactions on Image Processing 4 http://dx.doi.org/10.1109/TIP.2008.2011384 db/journals/tip/tip18.html#ZhangLWZ09