Image processing apparatus and image processing method for noise filtering
AssigneeCanon Kabushiki Kaisha
InventorShinya Hirai
Life of this patent
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Abstract
An input image is divided into images composed of luminance signals of a plurality of bands that make up the Laplacian pyramid, noise suppression is applied to each divided image, and then the divided images are composited by addition. The input image is also divided into images composed of color signals of a plurality of bands that make up the Gaussian pyramid, noise suppression is applied to each divided image, and the divided images are composited at an image-based ratio. By thus compositing the luminance signals and color signals, excellent noise suppression can be realized while alleviating deterioration in the image quality during the compositing.
Claims8
An image processing apparatus comprising:
- a first division circuit that divides an input image into images composed of luminance signals of a plurality of bands that make up a Laplacian pyramid;
- a plurality of luminance noise suppression circuits that each apply noise suppression to, out of the images divided by the first division circuit, an image composed of luminance signals of a corresponding band;
- an addition circuit that adds images output from the plurality of luminance noise suppression circuits;
- a second division circuit that divides the input image into images composed of color difference signals of a plurality of bands that make up a Gaussian pyramid;
- a plurality of color noise suppression circuits that each apply noise suppression to, out of the images divided by the second division circuit, an image composed of color difference signals of a corresponding band;
- and
- a compositing circuit that composites images output from the plurality of color noise suppression circuits at a ratio based on the images to be composited.
An image processing apparatus comprising:
- a processor;
- and
- a memory coupled to the processor, the memory having instructions that, when executed by the processor, perform operations comprising:
- first division processing for dividing an input image into images composed of luminance signals of a plurality of bands that make up a Laplacian pyramid;
- luminance noise suppression processing for applying noise suppression to each of the images divided in the first division processing;
- addition processing for adding images to which the luminance noise suppression processing has been applied;
- second division processing for dividing the input image into images composed of color difference signals of a plurality of bands that make up a Gaussian pyramid;
- color noise suppression processing for applying noise suppression to each of the images divided in the second division processing;
- and
- compositing processing for compositing images to which the color noise suppression processing has been applied at a ratio based on the images.
An image processing method comprising:
- (a) first dividing an input image into images composed of luminance signals of a plurality of bands that make up a Laplacian pyramid;
- (b) applying noise suppression to each of the images divided in the first division step;
- (c) adding images obtained in the luminance noise suppression step;
- (d) second dividing the input image into images composed of color difference signals of a plurality of bands that make up a Gaussian pyramid;
- (e) applying noise suppression to each of the images divided in the second dividing;
- and
- (f) composing images obtained in the applying at a ratio based on the images.
A non-transitory computer-readable recording medium having stored therein a program for causing a computer to execute an image processing method comprising:
- (a) first dividing an input image into images composed of luminance signals of a plurality of bands that make up a Laplacian pyramid;
- (b) applying noise suppression to each of the images divided in the first division step;
- (c) adding images obtained in the luminance noise suppression step;
- (d) second dividing the input image into images composed of color difference signals of a plurality of bands that make up a Gaussian pyramid;
- (e) applying noise suppression to each of the images divided in the second dividing;
- and
- (f) composing images obtained in the applying at a ratio based on the images.
Dependencies are inferred from the claim text.