Patent ID: 8437045
Filing Date: 2013-05-07
Classification: H04N

Abstract:
1. A method of performing black trapping on a color image data representation for rendering comprising: a) receiving a continuous tone data representation of a color image; b) generating a halftone pixel bitmap representing the color image, the halftone pixel bitmap including a black halftone pixel bitmap plane and one or more non-black pixel bitmap planes; c) identifying a qualified black pixel which is located substantially near a non-black pixel; d) estimating a continuous tone value associated with non-black pixels within a predetermined window of pixels associated with the qualified black pixel; and e) modifying the non-black halftone pixel bitmap plane at the qualified black pixel location using the estimated continuous tone value associated with the non-black pixels, wherein step d) estimates the continuous tone value associated with non-black pixels by determining a maximum halftone threshold associated with non-black pixels within the predetermined window and assigning the determined maximum halftone threshold as the estimated continuous tone value.