Abstract: A method compresses a digital continuous tone image of pixels situated on scan lines. The method includes the steps of, for a current pixel to be encoded, said current pixel having an actual pixel value, predicting a predicted pixel value based on pixel values of at least one previously processed pixel from the same image, using a fixed rule, determining a difference parameter based on a difference value of said predicted pixel value and the actual pixel value of said current pixel to be encoded, and inspecting the difference parameter for existence of an uninterrupted series of highest order bits having a value equal to zero, removing at least part of said highest order zero bits, and, if a number of bits within predetermined limits remains, generating a compression code having a predetermined fixed length, said code indicating the number of remaining bits.

Abstract: An image conversion method and an apparatus for converting a digital image obtained by a scanning unit into a converted digital image includes the steps of acquiring statistics for at least some pixels of the digital image, extracting characteristic values of a background color using the acquired statistics, operating a selection of pixels in the digital image, and converting the selected pixels. Each pixel in the digital image is sequentially set as a target pixel, and the selection of the target pixel depends on a representative color distance determined between a number of pixels located in a vicinity of the target pixel and the background color.

Abstract: A method compresses a digital continuous tone image of pixels situated on scan lines. The method includes the steps of, for a current pixel to be encoded, said current pixel having an actual pixel value, predicting a predicted pixel value based on pixel values of at least one previously processed pixel from the same image, using a fixed rule, determining a difference parameter based on a difference value of said predicted pixel value and the actual pixel value of said current pixel to be encoded, and inspecting the difference parameter for existence of an uninterrupted series of highest order bits having a value equal to zero, removing at least part of said highest order zero bits, and, if a number of bits within predetermined limits remains, generating a compression code having a predetermined fixed length, said code indicating the number of remaining bits.

Abstract: An image conversion method and an apparatus for converting a digital image obtained by a scanning unit into a converted digital image includes the steps of acquiring statistics for at least some pixels of the digital image, extracting characteristic values of a background color using the acquired statistics, operating a selection of pixels in the digital image, and converting the selected pixels. Each pixel in the digital image is sequentially set as a target pixel, and the selection of the target pixel depends on a representative color distance determined between a number of pixels located in a vicinity of the target pixel and the background color.