Gray component replacement

A printing device comprising:

• a printhead;
• a pixel gradient engine to analyze pixels of a digital image to determine, gradients corresponding to each pixel of the digital image;
• an activity mask engine to generate an activity mask for the digital image based at least in part on the gradients corresponding to each pixel of the digital image, the activity mask including an activity value for each pixel;
• an image processing engine to process the digital image by performing gray component replacement based at least in part on the activity mask to generate a color transformed image corresponding to the digital image;
• and
• a print engine to print the color transformed image with the printhead.

A method comprising:

• analyzing, with a processing resource, a plurality of pixels of a digital image to determine gradients corresponding to each pixel of the plurality based at least in part on a pixel value of each pixel;
• generating, with the processing resource and based at least in part on the corresponding gradients, a high frequency map for the digital image that indicates an amount of high frequencies corresponding to each pixel of the plurality;
• determining a degree of randomness corresponding to each pixel of the plurality based at least in part on the corresponding gradients;
• generating an activity mask based at least in part on the high frequency map and the degree of randomness corresponding to each pixel of the plurality, the activity mask comprising an activity value for each pixel of the digital image that is based on the amount of high frequencies corresponding to each pixel and the degree of randomness corresponding to each pixel, the activity mask identifying at least one granular area of the digital image that comprises a set of pixels having relatively higher activity values;
• and
• processing, with the processing resource, the digital image with the activity mask to generate a color transformed image by performing adaptive gray component replacement in the at least one granular area of the digital image.