Patent ID: 6244514
Filing Date: 2001-06-12
Classification: G06Q,G06T,G07F

Abstract:
A smart card for storing a digitally compressed image, the image containing image data consisting of a plurality of scan lines of pixels with scalar values, comprising:image data filtered by evaluation of the scalar values of individual pixels in the image with respect to neighboring pixels, said image data being statistically encoded by dividing the image into an array of blocks of pixels, and each block of pixels being encoded into a fixed number of bits that represent the pixels in the block;wherein said image data is filtered by determining an average of the data for a window of the pixels immediately surrounding the target pixel for those pixels surrounding the target pixel that are within a specified range of values, according to the following protocol: if all five pixels are within the specified range, the output target pixel is determined to be the average of the four pixels in a raster line on each side of the target pixel; if the two pixels on either side are within a specified range and both sides themselves are within the range, the target pixel is determined to be impulse noise, and the filtered output target pixel data is determined to be the average of the two pixels on each side of the target pixel; if the two pixels on either side of the target pixel and the target pixel itself are within a specified range, and the other two pixels on the other side are not within the specified range, the target pixel is determined to be an edge pixel, and the output target pixel is determined to be the average of the two pixels on the matching side that fall within the specified range; if the five pixels are all increasing or decreasing, or are within a small range to account for ringing or pre-emphasis typically found in analog video signals, the target pixel is treated as being in the mist of a blurred edge, and the output target pixel is then determined to be the average of two pixels on whichever side of the target pixel is closest in value to the target pixel; and if the five pixels in the window do not fit into any of the prior case, the output target pixels is unchanged; anda memory storing said image data.