Method of selective aperture sharpening and halo suppression using chroma zones in CMOS imagers

摘要

A method of suppressing a dark halo in an imager includes the steps of: extracting an edge value from an image; determining a chroma zone associated with the edge value extracted from the image; and modifying the edge value based on the chroma zone associated with the extracted edge value. The modified edge value from the imager is then provided to a user. The step of determining the chroma zone includes determining a chroma value of Cr and Cb in a Y-Cr-Cb color space; and modifying the edge value includes multiplying the edge value by a predetermined gain value, k, depending on the chroma value of Cr and Cb. If the value of Cr is greater than zero, then the gain value k is set close to zero, in order to suppress the dark halo in the modified edge value. On the other hand, if the value of Cr is less than zero, then the gain value k is set close to one, in order to sharpen the modified edge value in the image.

主权项

1. A method of suppressing a dark halo in an imager using processing circuitry, comprising the steps of:
using a high pass filter, extracting an edge value from an image; with the processing circuitry, determining a chroma zone associated with the edge value extracted from the image; modifying the edge value based on the chroma zone associated with the extracted edge value; demosaicing the image; and applying the modified edge value to the demosaiced image, wherein determining the chroma zone includes determining a chroma value of Cr and Cb in a Y-Cr-Cb color space, and modifying the edge value includes multiplying the edge value by a predetermined gain value, k, depending on the chroma value of Cr, wherein if the value of Cr is less than zero, then the gain value k is set to a value that is greater than one, in order to sharpen the modified edge value in the image.