Image processing method and apparatus for reducing noise of image obtained by radiography

An image processing apparatus configured to perform noise reduction on an image obtained by radiography in a recursive way comprising:

• an image input unit receiving frame-by-frame images obtained by the radiography;
• a motion detection image generating unit configured to generate a motion detection image comprising motion detection information for each pixel of a subtraction image obtained by a subtraction of a current frame image and a previous frame image;
• a motion probability image generating unit configured to generate a motion probability image based on the generated motion detection image and the motion detection image accumulated up to a previous frame;
• an output image generating unit configured to generate an output image of a current frame by mixing the current frame image and an output image of the previous frame based on the motion probability image;
• and
• a noise reducing unit configured to perform a noise reduction processing on the current frame image and the previous frame image,
• wherein the noise reducing unit performs the noise reduction processing in a unit of a mask having a plurality of adjacent pixels, and
• wherein the noise reducing unit is configured to perform the noise reduction processing based on a combination having a smallest sum of absolute values of a difference between a center pixel of the plurality of the pixels and adjacent pixels among combinations of the center pixel of the plurality of the pixels and the adjacent pixels neighboring the center pixel in a predetermined direction.

An image processing apparatus configured to perform noise reduction on an image obtained by radiography in a recursive way, comprising:

• an image input unit receiving frame-by-frame images obtained by the radiography;
• a motion detection image generating unit configured to generate a motion detection image comprising motion detection information for each pixel of a subtraction image obtained by a subtraction of a current frame image and a previous frame image;
• a motion probability image generating unit configured to generate a motion probability image based on the generated motion detection image and the motion detection image accumulated up to a previous frame;
• an output image generating unit configured to generate an output image of a current frame by mixing the current frame image and an output image of the previous frame based on the motion probability image;
• a noise reducing unit that is configured to perform a noise reduction processing on the current frame image and the previous frame image;
• and
• a noise stabilizing unit that is configured to perform a noise stabilization by reducing a noise deviation between the current frame image on which the noise reduction process is performed and the previous frame image,
• wherein the motion detection image generating unit comprises:
• a subtraction image generating unit that is configured to generate a subtraction image by a subtraction of the current frame image and the previous frame image;
• and
• a thresholding unit that is configured to generate the motion detection image including the motion detection information of each pixel through thresholding on pixel values of each pixel of the subtraction image.

An image processing apparatus configured to perform noise reduction on an image obtained by radiography in a recursive way, comprising:

• an image input unit receiving frame-by-frame images obtained by the radiography;
• a motion detection image generating unit configured to generate a motion detection image comprising motion detection information for each pixel of a subtraction image obtained by a subtraction of a current frame image and a previous frame image;
• a motion probability image generating unit configured to generate a motion probability image based on the generated motion detection image and a motion detection image accumulated up to a previous frame;
• and
• an output image generating unit configured to generate an output image of a current frame by mixing the current frame image and the output image of the previous frame based on the motion probability image,
• wherein the motion detection image generating unit is configured to distinguish between a subject and a background region and to generate a subject motion detection image for the subject and a background region motion detection image for the background region through thresholding with different threshold values, and then is configured to generate the motion detection image by merging the subject motion detection image and the background region motion detection image.

An image processing method for performing noise reduction on an image obtained by radiography in a recursive way, comprising:

• receiving frame-by-frame images obtained by the radiography;
• generating a motion detection image comprising motion detection information for each pixel of a subtraction image obtained by a subtraction of a current frame image and a previous frame image;
• generating a motion probability image based on the generated motion detection image and a motion detection image accumulated up to a previous frame;
• and
• generating an output image of a current frame by mixing the current frame image and an output image of the previous frame based on the motion probability image,
• wherein the motion probability image is generated by summing the motion detection image of the current frame and at least one of motion detection images up to the previous frame, and
• wherein a mixing ratio between the current frame image and the previous frame image is variably determined depending on a value indicating a degree of a motion of each pixel of the motion probability image.

An image processing method for performing noise reduction on an image obtained by radiography in a recursive way, comprising:

• receiving frame-by-frame images obtained by the radiography;
• generating a motion detection image comprising motion detection information for each pixel of a subtraction image obtained by a subtraction of a current frame image and a previous frame image;
• generating a motion probability image based on the generated motion detection image and a motion detection image accumulated up to a previous frame;
• and
• generating an output image of a current frame by mixing the current frame image and an output image of the previous frame based on the motion probability image,
• wherein the generating the motion detection image comprises distinguishing between a subject and a background region and generating a subject motion detection image for the subject and a background region motion detection image for the background region through thresholding with different threshold values, and then generating the motion detection image by merging the subject motion detection image and the background region motion detection image.