RADIOGRAPHIC IMAGE CAPTURING SYSTEM

• US 20160302755A1
• Filed: 04/07/2016
• Published: 10/20/2016
• Est. Priority Date: 04/14/2015
• Status: Active Grant

• Current Assignee: Konica Minolta Inc.
• Original Assignee: Konica Minolta Inc.
• Inventors: SUHARNO, Agus, TAKAGI, Tatsuya, MATSUMOTO, Hiroaki, ITO, Ryohei, KOBAYASHI, Tsuyoshi
• Granted Patent: US 10,149,656 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 6/4283 characterised by a detector unit being housed in a cassette
• CPC Class Codes: A61B 6/505 for diagnosis of bone
• CPC Class Codes: A61B 6/5241 combining overlapping images of the same imaging modality, e.g. by stitching
• CPC Class Codes: A61B 6/5252 removing objects from field of view, e.g. removing patient table from a CT image
• CPC Class Codes: A61B 6/582 Calibration
• CPC Class Codes: A61B 6/585 Calibration of detector units
• CPC Class Codes: A61B 6/588 Setting distance between source unit and detector unit
• CPC Class Codes: G06T 2207/20224 Image subtraction
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/77 Retouching; Inpainting; Scratch removal

Abstract

A radiographic image capturing system includes the following. A capturing stand includes a holder to hold radiographic image capturing devices. A radiation irradiator is able to irradiate the radiographic image capturing devices at once. An image processor generates images based on image data acquired by the radiographic image capturing devices. The image processor removes a structural component derived from the front radiographic image capturing device, on the basis of a calibration image and the generated image. The calibration image is preliminarily generated based on the image data acquired by the rear radiographic image capturing device with no subject disposed. The generated image is generated based on the image data acquired by the rear radiographic image capturing device during actual image capturing. The image processor removes a streaky component residing in the generated image.

Claims

1. A radiographic image capturing system comprising:

a capturing stand which includes a holder which is able to hold a plurality of radiographic image capturing devices;

a radiation irradiator which is able to irradiate the radiographic image capturing devices loaded in the holder at once with radiation; and

an image processor which generates a plurality of images based on image data acquired by the radiographic image capturing devices,

wherein,

an edge of a front radiographic image capturing device overlaps in an anteroposterior direction with an edge of a rear radiographic image capturing device in the holder in view from the radiation irradiator, the front radiographic image capturing device being a radiographic image capturing device close to the radiation irradiator among the radiographic image capturing devices loaded in the holder, the rear radiographic image capturing device being a radiographic image capturing device remote from the radiation irradiator among the radiographic image capturing devices loaded in the holder,

the image processor removes a structural component derived from the front radiographic image capturing device projected on a generated image, on the basis of a calibration image and the generated image, the calibration image being preliminarily generated based on the image data acquired by the rear radiographic image capturing device irradiated with radiation with no subject disposed in front of the radiographic image capturing devices loaded in the holder of the capturing stand, the generated image being generated based on the image data acquired by the rear radiographic image capturing device during actual image capturing of a subject, and

the image processor removes a streaky component residing in the generated image on the basis of the generated image, to correct the image.

2. The radiographic image capturing system according to claim 1, wherein, the image processor corrects the image through removal of the structural component and removal of the streaky component remaining in the image after the removal of the structural component.

3. The radiographic image capturing system according to claim 2, wherein, the image processor removes the structural component from each image generated based on the image data acquired by each radiographic image capturing device loaded in the holder of the capturing stand, combines the images from which the structural component is removed, and removes the streaky component remaining in a combined image generated by combining the images.

4. The radiographic image capturing system according to claim 3, wherein, the image processor combines the images at an overlapping area of the images, the overlapping area including the image captured by the rear radiographic image capturing device in the holder of the capturing stand.

5. The radiographic image capturing system according to claim 1, wherein, the image processor corrects the image through removal of the streaky component and removal of the structural component remaining in the image after the removal of the streaky component.

6. The radiographic image capturing system according to claim 1, wherein, during removal of the structural components, the image processor,

calculates a value k(x,y) based on the calibration image, the value k(x,y) being added to a pixel value f(x,y) of a pixel (x,y) in an area of the image on which the structural component of the front radiographic image capturing device is projected,

calculates a corrected pixel value g(x,y) determined by adding the product of the value k(x,y) and a coefficient A(x,y) to the pixel value f(x,y), as defined by an expression (1), to remove the structural component:

g(x,y)=f(x,y)+A(x,y)×

k(x,y) 

 

(1), and

determines the coefficient A(x,y) as a minimum sum of a value e(x,y) calculated by an expression (2) within a region of interest assigned to include a target pixel on the image;

e(x,y)={g(x+1,y)−

g(x−

1,y)}²+{g(x,y+1)−

g(x,y−

1)}² 

 

(2)

7. The radiographic image capturing system according to claim 1, wherein, during removal of the streaky component, the image processor,

subtracts a background component from a component acquired through horizontal smoothening of a region assigned in the image containing the streaky component, to extract the streaky component, and

adds the extracted streaky component to a pixel value of each pixel in the image, to remove the streaky component from the image.

8. The radiographic image capturing system according to claim 1, wherein, the image processor corrects the image and carries out image processing to adjust contrast and granularity of an area of the image from which the structural component and the streaky component are removed to match the contrast and granularity with another area in the image.

9. The radiographic image capturing system according to claim 8, wherein, the process of adjusting the contrast and the granularity of the image includes resolving an area of the corrected image from which the structural component and the streaky component are removed into images having different frequency bands, multiplying the images having different frequency bands with a predetermined amplification factor, and adding together the images having different frequency bands multiplied with the amplification factor.

10. A radiographic image capturing system comprising:

a capturing stand which includes a holder which is able to hold a plurality of radiographic image capturing devices;

a radiation irradiator which is able to irradiate the radiographic image capturing devices loaded in the holder at once with radiation; and

an image processor which generates a plurality of images based on image data acquired by the radiographic image capturing devices,

wherein,

an edge of a front radiographic image capturing device overlaps in an anteroposterior direction with an edge of a rear radiographic image capturing device in the holder in view from the radiation irradiator, the front radiographic image capturing device being a radiographic image capturing device close to the radiation irradiator among the radiographic image capturing devices loaded in the holder, the rear radiographic image capturing device being a radiographic image capturing device remote from the radiation irradiator among the radiographic image capturing devices loaded in the holder,

the image processor removes a streaky component residing in the generated image based on the generated image, to correct the image, and

the image processor subtracts a background component from a component acquired through horizontal smoothing of a region assigned in the image containing the streaky component during removal of the streaky component, to extract the streaky component, and adds the extracted streaky component to a pixel value of each pixel in the image, to remove the streaky component from the image.

11. The radiographic image capturing system according to claim 10, wherein, the image processor corrects the image and carries out image processing to adjust contrast and granularity of an area of the image from which the streaky component is removed to match the contrast and granularity with another area of the image.

12. The radiographic image capturing system according to claim 11, wherein, the process of adjusting the contrast and the granularity of the image includes resolving an area of the corrected image from which the streaky component is removed into images having different frequency bands, multiplying the images having different frequency bands with a predetermined amplification factor, and adding together the images having different frequency bands multiplied with the amplification factor.