Signal processing apparatus and method for reducing jaggedness on color image edge and image sensing apparatus having same
AssigneeCanon Kabushiki Kaisha
InventorsEiichiro Ikeda, Toshiaki Endo, Takaaki Fukui
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Abstract
In a signal processing apparatus for processing an image signal, a hue difference between adjoining pixels is detected by a color image edge detector, and an aperture control main gain circuit amplifies a luminance signal using a gain determined on the basis of the hue difference detected by the color image edge detector to enhance an edge pixel of an image.
Claims12
A signal processing apparatus for processing an image signal comprising:
- a hue difference detector for detecting a hue difference between adjoining pixels;
- and
- luminance edge enhancement means for enhancing an edge pixel in an image by amplifying an edge luminance signal by a gain determined on the basis of the hue difference detected by said hue difference detector, wherein said hue difference detector includes:
- hue angle acquisition means for acquiring a hue angle of each pixel;
- a subtractor for obtaining a hue angle difference between adjoining pixels;
- and diffusion means for diffusing the hue angle difference.
A signal processing method for processing an image signal comprising:
- a hue difference detection step of detecting a hue difference between adjoining pixels;
- and
- a luminance edge enhancement step of enhancing an edge pixel in an image by amplifying an edge luminance signal by a gain determined on the basis of the hue difference detected at said hue difference detection step, wherein said hue difference detection step includes:
- a hue angle acquisition step of acquiring a hue angle of each pixel;
- a subtracting step of obtaining a hue angle difference between adjoining pixels;
- and a diffusion step of diffusing the hue angle difference.
A computer program product for reducing jaggedness on color image edges comprising a computer readable medium having computer readable program code means embodied in said medium for a signal processing method for processing an image signal, said computer program product including:
- first computer readable program code means for detecting a hue difference between adjoining pixels;
- and
- second computer readable program code means for enhancing an edge pixel in an image by controlling an edge luminance signal by a gain detennined on the basis of the detected hue difference,
- wherein said first computer readable program code means includes:
- third computer readable program code means for acquiring a hue angle of each pixel;
- fourth computer readable program code means for obtaining a hue angle difference between adjoining pixels;
- and
- fifth computer readable program code means for diffusing the hue angle difference,
- whereby the jaggedness on color image edges is reduced.
Dependencies are inferred from the claim text.