Apparatus for eliminating moire in scanned image and method for the same
View Patent ↗A method for eliminating moire in scanned digital image comprises the steps of using an average circuit for taking weighted average and error diffusing a gray level difference between an error diffusion pixel G ij and neighbor pixels to neighbor to obtain output image pixel Y′ ij ; using a second adder for subtracting the error diffusion pixel G ij from the output image pixel Y′ ij to obtain a neighbor image error d ij ; using a error filter H(z) to process the neighbor image error d ij to obtain a corrected pixel error H(d(i,j)); and using a first adder for adding the corrected pixel error H(d(i,j)) and the input image pixel Y ij to obtain the corrected error diffusion pixel G ij , and then jumping to first step until all pixels being processed. The method provides real time treatment for eliminating moire and provide smooth image.
1. A method for eliminating moire in scanned digital image, comprising following steps:
(a). using an average circuit for taking weighted average and error diffusing a gray level difference between an error diffusion pixel G ij and neighbor pixels to neighbor to obtain output image pixel Y′ ij ;
(b). using a second adder for operating the error diffusion pixel G ij and the output image pixel Y′ ij to obtain a neighbor image error d ij ;
(c). using a error filter H(z) to process the neighbor image error d ij to obtain a corrected pixel error H(d(i,j)); and
(d). using a first adder for operating the corrected pixel error H(d(i,j)) and the input image pixel Y ij to obtain the corrected error diffusion pixel G ij , and then jumping to step (a) until all pixels being processed.
2. The method for eliminating moire in scanned digital image as claim 1 , wherein in the step (a), the average circuit chooses different weight according a complexity of the moire to be eliminated.
3. The method for eliminating moire in scanned digital image as claim 1 , wherein in the step (b) the second adder subtracts the error diffusion pixel G ij , from the output image pixel Y′ ij to obtain a neighbor image error d ij .
4. The method for eliminating moire in scanned digital image as claim 1 , wherein in the step (d) the first adder adds the corrected pixel error H(d(i,j)) with the input image pixel Y ij to obtain the corrected error diffusion pixel G ij , and then jumping to step (a) until all pixels being processed.
5. The method for eliminating moire in scanned digital image as claim 1 , wherein each image is segmented to a plurality of line images for processing, the average value of one pixel with neighbor pixel in one line being used as reference value of average circuit processing next line.