Uniformity compensation in halftoned images

A method for compensating for a spatial non-uniformity in an image rendering device, the method comprising:

• predetermining a spatially dependent compensating tone reproduction curve for the rendering device;
• receiving a halftoned image including a plurality of respective halftone pixels having respective halftone pixel values, the respective halftone pixels being associated with respective halftone pixel positions in the image;
• estimating respective gray values associated with respective halftone pixels;
• and
• determining respective compensated values for respective halftone pixels based on the respective halftone pixel positions, the respective estimated gray values, the spatially dependent compensating tone reproduction curve and the respective halftone pixel values.

A system operative to compensate a halftoned image for spatial non-uniformity in an image rendering device, the system comprising:

• a modification value determiner that is operative to receive respective pixel position information regarding a respective pixel of a halftoned image, and determine a spatially dependent modification value from a compensating tone reproduction curve associated with the image rendering device based on the pixel position information from the received halftoned image data;
• a combiner that is operative to receive the spatially dependent modification value from the modification value determiner, receive a respective pixel value associated with the respective pixel of the halftoned image and combine the respective pixel value associated with the respective pixel with the modification value, thereby generating a combined value;
• and
• a quantizer that is operative to receive the combined value from the combiner and to quantize the combined value, thereby producing a compensated halftone pixel value associated with the respective pixel position of the respective pixel of the halftoned image.