| 摘要 |
Enhancing an image by upsampling 18 the spatial resolution of a chrominance component 14 of the image, then applying a guided image filter 20 with an adaptive radius parameter which is variable for different pixels of the image. The guided image filter takes a filter image 19 and a guidance image 17 as inputs and the radius parameter determines the spatial extent or kernel size of the filter. The original image has a luminance component with a higher spatial resolution than the chrominance component and preferably the guidance image 17 is the luminance component. The window size or radius of the filter may be determined by analysing the luminance image data in a window around the current pixel. A histogram 15 may be formed from the luminance values used in the analysis and the radius could be inversely proportional to the number of brightness levels in the histogram. An apparatus claim is also included. |
