Image processing apparatus, image processing method, and image processing program
An image acquisition unit acquires first and second radiation images from first and second radiation detectors. A first frequency analysis unit generates a first high-frequency component and a first low-frequency component of the first radiation image, and a second frequency analysis unit generates a second low-frequency component of the second radiation image. A subtraction processing unit generates a subtraction low-frequency component from the first low-frequency component and the second low-frequency component, and a synthesis unit synthesizes the subtraction low-frequency component and the first high-frequency component to generate a processed image.
1. An image processing apparatus comprising:
a storage device, storing information on corresponding relationships between different imaging portions of a subject and a plurality of frequency bands, wherein each corresponding relationship includes a predetermined range of frequency bands for extracting a specific structure in an imaging portion of the subject; and
a processor configured to,
acquire two radiation images obtained by radiation rays passed through an imaging portion of the subject, having different energy distributions and different amounts of radiation,
generate a first high-frequency component and a first low-frequency component which are a high-frequency component and a low-frequency component of a first radiation image acquired by radiation having a large amount of radiation among the two radiation images,
generate a second low-frequency component which is a low-frequency component of a second radiation image acquired by radiation having a small amount of radiation among the two radiation images,
perform weighting and subtraction between corresponding pixels with respect to the first low-frequency component and the second low-frequency component to generate a subtraction low-frequency component obtained by extracting a specific structure of the subject, and
synthesize the subtraction low-frequency component and the first high-frequency component to generate a processed image,
wherein the first high-frequency component and the first low-frequency component are generated to have different frequency bands according to one of the corresponding relationships stored in the storage device, wherein the first high-frequency component has a highest frequency band in a predetermined range of frequency bands for extracting the specific structure in the imaging portion of the subject, and the first low-frequency component has a lowest frequency band in the predetermined range of frequency bands, and
wherein the second low-frequency component is generated to have the same frequency band as the first low-frequency component.
2. The image processing apparatus according to claim 1 ,
wherein the processor performs weighting and synthesis with respect to the subtraction low-frequency component and the first high-frequency component according to a body thickness of the subject to generate the processed image.
3. The image processing apparatus according to claim 1 ,
wherein the processor performs weighting and synthesis with respect to the subtraction low-frequency component and the first high-frequency component according to a density of the first radiation image or the second radiation image to generate the processed image.
4. An image processing method comprising:
acquiring two radiation images obtained by radiation rays passed through an imaging portion of a subject, having different energy distributions and different amounts of radiation;
generating a first high-frequency component and a first low-frequency component which are a high-frequency component and a low-frequency component of a first radiation image acquired by radiation having a large amount of radiation among the two radiation images;
generating a second low-frequency component which is a low-frequency component of a second radiation image acquired by radiation having a small amount of radiation among the two radiation images;
performing weighting and subtraction between corresponding pixels with respect to the first low-frequency component and the second low-frequency component to generate a subtraction low-frequency component obtained by extracting a specific structure of the subject; and
synthesizing the subtraction low-frequency component and the first high-frequency component to generate a processed image,
wherein the first high-frequency component and the first low-frequency component are generated according to a corresponding relationship between the imaging portion of the subject and a plurality of frequency bands, wherein the corresponding relationship includes a predetermined range of frequency bands for extracting the specific structure in the imaging portion of the subject, the first high-frequency component has a highest frequency band in the predetermined range of frequency bands, and the first low-frequency component has a lowest frequency band in the predetermined range of frequency bands, and
wherein the second low-frequency component is generated to have the same frequency band as the first low-frequency component.
5. A non-transitory computer-readable recording medium having stored therein an image processing program that causes a computer to execute:
a process of acquiring two radiation images obtained by radiation rays passed through an imaging portion of a subject, having different energy distributions and different amounts of radiation;
a process of generating a first high-frequency component and a first low-frequency component which are a high-frequency component and a low-frequency component of a first radiation image acquired by radiation having a large amount of radiation among the two radiation images;
a process of generating a second low-frequency component which is a low-frequency component of a second radiation image acquired by radiation having a small amount of radiation among the two radiation images;
a process of performing weighting and subtraction between corresponding pixels with respect to the first low-frequency component and the second low-frequency component to generate a subtraction low-frequency component obtained by extracting a specific structure of the subject; and
a process of synthesizing the subtraction low-frequency component and the first high-frequency component to generate a processed image,
wherein the first high-frequency component and the first low-frequency component are generated according to a corresponding relationship between the imaging portion of the subject and a plurality of frequency bands, wherein the corresponding relationship includes a predetermined range of frequency bands for extracting the specific structure in the imaging portion of the subject, the first high-frequency component has a highest frequency band in the predetermined range of frequency bands, and the first low-frequency component has a lowest frequency band in the predetermined range of frequency bands, and
wherein the second low-frequency component is generated to have the same frequency band as the first low-frequency component.