Method and system for converting images in computer systems

Abstract

The present invention provides a method and system in computer systems for converting an original image into another image having fewer colors than the original image. This method and system attempt to preserve the contrast of the original image. As a result, this method and system are particularly well-suited for converting images that are relatively small in size. A computer system in which the present invention operates includes a computer connected to a display device and a secondary storage device. An image converter is stored in the secondary storage device for execution by the computer. In operation, the computer receives an original image to be displayed on the display device. The image converter converts the original image into another image having fewer colors than the original image. Lastly, the computer displays the converted image on the display device. In order to convert the original image, the image converter determines which pixels in the original image are opaque in the converted image. For the pixels that are opaque in the converted image, the image converter determines a gray-scale representation of the pixels. For the same pixels, the image converter then determines a black-and-white representation of the pixels. Next, the image converter determines the color assigned to the black pixels in the converted image and the color assigned to the white pixels in the converted image. Lastly, the image converter specifies the representation of the converted image.