Abstract: A process for enhancing a decompressed JPEG image data defined by a two-dimensional array of pixel values is disclosed. The enhancement involves sharpening real objects in the image and avoids the sharpening of compression artifacts. The process includes selecting a first pixel value to be enhanced, a group of pixel values surrounding the first pixel from the array of pixel values, and a threshold value. The first pixel value is changed to an enhanced value by first taking the differences in pixel values between each pixel value in the group and the first pixel. These differences in values are compared with the threshold value. Those differences in values that exceed the threshold value are then used to calculate the enhanced value. More specifically, the enhanced value is given by the sum of a scaled average of the differences in values and the original pixel value.

Abstract: A method for merging images is disclosed. The present invention may be implemented as a method for merging two or more images to produce a merged image using a mask. Each of these images has mutually corresponding pixels. In other words, each pixel value in an image has a spatially corresponding pixel in the other images. The mask has mask values, each mask value corresponding to a pixel in an image. The mask value is used to determine the corresponding pixel value of the merged image. One embodiment uses this mask value to set a corresponding pixel value of the merged image to a pixel value of one of the two or more images. Another embodiment uses the mask value as a weight. This weight is used to calculate the pixel value as a combination of corresponding pixel values of the two or more images. By using such a mask, a merged image may be formed avoiding artifacts resulting from decompressing a highly compressed image.