Image processing device, image processing method, and computer program

An image processing device for eliminating or reducing noise from an input image comprising a plurality of pixels arranged in a matrix to generate an output image, the image processing device comprising:

• specific area extraction means configured to extract a specific area comprising a target pixel from the input image;
• smoothing determination means configured to determine whether to perform a first smoothing process on the target pixel, on the basis of the specific area extracted by the specific area extraction means;
• first smoothing means configured to, if the smoothing determination means determines that the first smoothing process is to be performed on the target pixel, perform the first smoothing process using a smoothing filter to smooth a value of the target pixel;
• and
• second smoothing means configured to, if the smoothing determination means determines that the first smoothing process is not to be performed on the target pixel, perform a second smoothing process using an edge-preserving smoothing filter to smooth the value of the target pixel,
• wherein the image processing device generates an output image by replacing a value of each pixel in the input image with either a pixel value smoothed by the first smoothing means or a pixel value smoothed by the second smoothing means.

An image processing device comprising:

• specific area extraction means configured to extract a specific area comprising a target pixel from an input image comprising a plurality of pixels arranged in a matrix;
• differential calculation means configured to calculate differentials between values of pixels in an image of the specific area extracted by the specific area extraction means;
• noise boundary direction determination means configured to determine an extending direction of a boundary of noise in the specific area on the basis of the differentials calculated by the differential calculation means;
• and
• noise boundary position determination means configured to determine a position of the noise boundary in the specific area on the basis of the differentials calculated by the differential calculation means.

An image processing method for eliminating or reducing noise from an input image comprising a plurality of pixels arranged in a matrix to generate an output image, the method comprising:

• a specific area extraction step of extracting a specific area comprising a target pixel from the input image;
• a smoothing determination step of determining whether to perform a first smoothing process on the target pixel, on the basis of the specific area extracted in specific area extraction step;
• a first smoothing step of, if it is determined in the smoothing determination step that the first smoothing process is to be performed on the target pixel, performing the first smoothing process using a smoothing filter to smooth a value of the target pixel;
• a second smoothing step of, if it is determined in the smoothing determination step that the first smoothing process is not to be performed on the target pixel, performing a second smoothing process using an edge-preserving smoothing filter to smooth the value of the target pixel;
• and
• a generation step of generating an output image by replacing a value of each pixel in the input image with either a pixel value smoothed in the first smoothing step or a pixel value smoothed in the second smoothing step.

An image processing method comprising:

• a specific area extraction step of extracting a specific area comprising a target pixel from an input image comprising a plurality of pixels arranged in a matrix;
• a differential calculation step of calculating differentials between values of pixels in an image of the specific area extracted in the specific area extraction step;
• a noise boundary direction determination step of determining an extending direction of a boundary of noise in the specific area on the basis of the differentials calculated in the differential calculation step;
• and
• a noise boundary position determination step of determining a position of the noise boundary in the specific area on the basis of the differentials calculated in the differential calculation step.