Methods, computer program products and apparatuses are disclosed for
processing images to detect and/or remove halftone. In one aspect, a
portion of an image comprising a plurality of color channels is selected
for processing (210), a frequency domain representation of the selected
portion is generated for each color channel (220), data relating to
predetermined regions in the frequency domain representations is
processed (230), and halftone present in the selected portion is detected
based on a result of the processing the data (240). In another aspect, an
image is arranged into a plurality of bands each comprising a
predetermined number of consecutive lines of pixels, each of the
plurality of bands is arranged into a plurality of tiles of pixels, one
of the plurality of tiles is selected as a selected portion, data
relating to the selected portion is processed and halftone present in the
selected portion is detected based on a result of the processing and on a
result of processing at least one other portion of the image. Halftone
may be detected based on spatial characteristics or frequency
characteristics within the selected portion and detected halftone may be
removed from spatial domain data or frequency domain data relating to the
selected portion.