Patent ID: 7409103

Claim:
A method of reducing image noise which emerges in an image imported from a digital camera equipped with a CCD or other light sensitive device, the method comprising: applying a first filtering step to luminance component image data of the image with each pixel of said luminance component image data being designated as a target pixel, thereby creating luminance component image data with its entirety smoothened; and applying a second filtering step to color-difference component image data of the image with each pixel of said color-difference component image data being designated as a target pixel, thereby creating color-difference component image data with its entirety smoothened, wherein said method is applied to an image imported from the digital camera whose image data is once encoded on a block-by-block basis and then decoded after imported, said method further comprising: dividing each of luminance component image data and color-difference component image data of said image data into blocks corresponding to the blocks created in the encoding and decoding of the image data; applying a third filtering step to the luminance component image data with each of pixels on the boundaries of the blocks being designated as a target pixel, thereby creating a first luminance component image data with the boundaries of the blocks smoothened; performing a fourth filtering step with each pixel of the first luminance component image data being designated as a target pixel, thereby creating a second luminance component image data with its entirety smoothened; creating edge image data by subtracting each pixel value of the second luminance component image data from a corresponding pixel value of the first luminance component image data; creating corrected edge image data with each difference value of the edge image data corrected under given conditions; creating a third luminance component image data by adding each offset value of the corrected edge image data to its corresponding pixel value of the second luminance component image data; applying a fifth filtering step to the color-difference component image data with each pixel of the color-difference component image data being designated as a target pixel, thereby creating a first color-difference component image data with its entirety smoothened; and then applying any one of the first and second filtering steps to the third luminance component image data and the first color-difference component image data.