Back to results
US 8,300,120 B2Granted
Image processing apparatus and method of processing image for reducing noise of the image
AssigneeCanon Kabushiki Kaisha
InventorMakoto Shohara
Life of this patent
Estimating the term…
Abstract
An image processing apparatus calculates a smoothed value obtained by smoothing signal levels of a plurality of pixels including a processing target pixel in a local area of an input image and a feature amount representing an edge degree of the processing target pixel using a pre-noise reduction image obtained by reducing an impulse noise of the input image. The image processing apparatus weighted-adds a signal level of the processing target pixel and the smoothed value at a ratio corresponding to the feature amount and outputs the weighted-addition result as a signal level after noise reduction processing.
Claims9
An image processing apparatus comprising:
- a noise reduction unit configured to generate a pre-noise reduction image obtained by reducing an impulse noise of an input image;
- a smoothing unit configured to calculate a smoothed value obtained by smoothing signal levels of a plurality of pixels including a processing target pixel in a local area of the input image;
- a feature amount calculation unit configured to calculate a feature amount representing an edge degree of the processing target pixel using the pre-noise reduction image;
- and
- an addition unit configured to weighted-add a signal level of the processing target pixel and the smoothed value at a ratio corresponding to the feature amount and to output the weighted addition result as a signal level after noise reduction processing of the input image,
- wherein as a ratio of a variance value of the signal levels of a plurality of pixels including a processing target pixel in a local area of the pre-noise reduction image to a variance value of noises of the pre-noise reduction image increases, the edge degree represented by the feature amount increases, and
- wherein as the edge degree represented by the feature amount increases, a ratio of a weighting of the smoothed value to a weighting of the signal level of the processing target pixel decrease.
4 more elements
An image processing apparatus comprising:
- a noise reduction unit configured to generate a pre-noise reduction image obtained by reducing an impulse noise of an input image;
- a smoothing unit configured to calculate a smoothed value obtained by smoothing signal levels of a plurality of pixels including a processing target pixel in a local area of the input image;
- a feature amount calculation unit configured to calculate a feature amount representing an edge degree of the processing target pixel using the pre-noise reduction image;
- and
- an addition unit configured to weighted-add a signal level of the processing target pixel and the smoothed value at a ratio corresponding to the feature amount and to output the weighted addition result as a signal level after noise reduction processing of the input image,
- wherein the edge degree represented by as the feature amount increase, a ratio of a weighting of the smoothed value to a weighting of the signal level of the processing target pixel decreases, and
- wherein as a sensitivity set in an image apparatus when the input image is captured increases, the ratio of the weighting of the smoothed value to the weighting of the signal level of the processing target pixel increase.
4 more elements
An image processing method comprising:
- generating a pre-noise reduction image obtained by reducing an impulse noise of an input image;
- calculating a smoothed value obtained by smoothing signal levels of a plurality of pixels including a processing target pixel in a local area of the input image;
- calculating a feature amount representing an edge degree of the processing target pixel using the pre-noise reduction image;
- and
- weighted-adding a signal level of the processing target pixel and the smoothed value at a ratio corresponding to the feature amount and outputting the weighted addition result as a signal level after noise reduction processing of the input image,
- wherein as a ratio of the variance value of the signal levels of a plurality of pixels including a processing target pixel in a local area of the pre-noise reduction image to the variance value of noises of the pre-noise reduction image increases, the edge degree represented by the feature amount increases, and
- wherein as the edge degree represented by the feature amount increase, a ratio of a weighting of the smoothed value to a weighting of the signal level of the processing target pixel decreases.
4 more elements
An image processing method comprising:
- generating, using a processor, a pre-noise reduction image obtained by reducing an impulse noise of an input image;
- calculating, using the processor, a smoothed value obtained by smoothing signal levels of a plurality of pixels including a processing target pixel in a local area of the input image;
- calculating, using the processor, a feature amount representing an edge degree of the processing target pixel using the pre-noise reduction image;
- and
- weighted-adding, using the processor, a signal level of the processing target pixel and the smoothed value at a ratio corresponding to the feature amount and outputting the weighted addition result as a signal level after noise reduction processing of the input image,
- wherein the edge degree represented by as the feature amount increase, a ratio of a weighting of the smoothed value to a weighting of the signal level of the processing target pixel decreases, and
- wherein as a sensitivity set in an image apparatus when the input image is captured increases, the ratio of the weighting of the smoothed value to the weighting of the signal level of the processing target pixel increase.
4 more elements
Dependencies are inferred from the claim text.