Texture preserving noise reduction for ultra high ISO images

We present a novel method to reduce a sparkle and impulse noise of high ISO images. We employ diverse approach for a intensity(Y) image and two Color images (CB,CR) separately. For the intensity image, we propose a frequency cut based texture analysis to distinguish between noise patch and texture patch. A noise analysis calibration is proposed depending on exposure time, ISO and sensor size for the parameter extraction. The intensity noise is removed by a frequency magnitude cut based noise reduction assuming that the pattern patch has much higher magnitude than noise patch. However the color parts produce big size of noise mass after CFA interpolation. We proposed a coincidental smoothing filter for removing the color noise mass by applying the Gaussian function to the strength of the color. Finally we blend an input noisy image to a noise reduced image and add Gaussian noise for making a natural image and reducing some pattern loss.