JP7326807B2 - Image processing device, display device, tomographic image display system, image processing method, and program - Google Patents

Description

The present disclosure relates to a medical image processing apparatus and image processing method, and more particularly to image processing and display of mammography images acquired by tomosynthesis imaging.

2. Description of the Related Art Conventionally, mammography is known as an imaging device for imaging breast images in the medical field. A mammography apparatus acquires digital image data by, for example, irradiating X-rays toward a subject's breast and detecting the X-rays that have passed through the subject.

On the other hand, in recent years, a tomosynthesis imaging method has been used as a technique for obtaining voxel data, which is data representing density and density distributions in space (see, for example, Patent Document 1). In the tomosynthesis imaging method, imaging is performed a plurality of times while an X-ray source and a detector are moved relative to a subject, and voxel data is constructed to reconstruct a plurality of tomographic images. By performing tomosynthesis imaging in place of mammography, it is possible to obtain information on the direction in which X-rays pass through in mammography, making it possible to perform examinations with higher accuracy.

International Patent Application Publication No. 2015/059933 JP 2011-104149 A JP 2011-125363 A

Since an X-ray image of a breast is generally very fine and has a low subject contrast, the brightness of a display device (monitor) is generally high during interpretation. Therefore, in order to prevent the examiner from feeling dazzled, when interpreting a mammography image, for example, processing is performed to display the non-breast region in a dark color based on the skin line corresponding to the skin (for example, Patent Document 2). , see Patent Document 3). However, in the case of tomosynthesis imaging, a large number of tomographic images with different positions of corresponding planes for one subject can be obtained in a single imaging session. There is a problem that the display speed decreases.

The present disclosure has been made in view of the above problems, and aims to improve the image display speed by reducing the amount of operations for darkening processing.

An image processing device according to an aspect of the present disclosure is an image processing device that displays a plurality of tomographic images on a display device, and is an image processing device that acquires a plurality of tomographic images acquired from a breast of a subject as a group of tomographic images. a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the tomographic image group; a mask setting unit that sets a mask region in the non-breast region of the first tomographic image based on the skin line of the image; an image processing unit that darkens the same area as the mask area of the first tomographic image and displays it on a display device , the skin line detecting unit detects skin lines from the plurality of tomographic images, and The setting unit is characterized in that, among the plurality of tomographic images, a tomographic image having the largest area of the breast region is selected as the first tomographic image.

According to the above configuration, the second tomographic image is darkened based on the skin line extraction result of the first tomographic image. Therefore, it is not necessary to perform skin line extraction processing on all the tomographic images forming the tomographic image group, and the amount of calculation can be reduced to improve the display speed of tomographic images.

1 is a schematic diagram showing the configuration of an image display system 1000 according to an embodiment; FIG. (a) is a schematic diagram showing an outline of three-dimensional voxel data 400 according to the embodiment, and (b) is a schematic diagram showing an outline of a tomographic image group 420 according to the embodiment. 4 is a schematic diagram showing the flow of processing for a tomographic image group 420 of the image processing apparatus 100. FIG. 4 is a schematic diagram showing an overview of image processing and display processing of a group of tomographic images 420 of the image processing apparatus 100. FIG. 4 is a flowchart showing the operation of the image processing apparatus 100; (a) is a schematic diagram of a process of extracting a skin line from a tomographic image, (b) is a schematic diagram showing an example of the extracted skin line, and (c) is a schematic diagram showing an example of setting a mask area. is. (a) and (b) are schematic diagrams showing setting examples of mask regions, and (c) is a schematic diagram showing an example of display of a tomographic image. 1 is an external view of a breast tomosynthesis imaging apparatus; FIG. FIG. 2 is a schematic diagram showing an outline of processing for constructing three-dimensional voxel data in tomosynthesis;

<<Embodiment>>
An image display system 1000 according to an embodiment will be described below with reference to the drawings.

≪Overall composition≫
FIG. 1 is a functional block diagram of an image display system 1000 according to an embodiment. As shown in FIG. 1, the image display system 1000 includes a tomographic image database 200 that stores and manages three-dimensional voxel data, an image processing device 100, and a display device 300. FIG.

<Tomographic image database 200>
The tomographic image database 200 is a server device that stores and manages a plurality of tomographic images based on three-dimensional voxel data as one tomographic image group. Three-dimensional voxel data and tomographic image groups will be described later. The tomographic image database 200 includes a storage for storing a plurality of tomographic images forming a group of tomographic images, and an interface for communicating with the image processing apparatus 100 . The tomographic image database 200, for example, is implemented as a computer including a processor, memory, and software, and includes a hard disk, SSD, etc. as a storage, and an interface card compatible with 10GBASE-T as an interface.

<Display device 300>
The display device 300 is a display device that is connected to the image processing device 100 and displays an image that is output from the image processing device 100 . The display device includes, for example, a liquid crystal display, an organic EL display, a CRT, etc., and includes, for example, DVI, DisplayPort, etc. as an interface for receiving an image from the image processing device 100 .

<<Configuration of Image Processing Apparatus 100>>
The image processing apparatus 100 is an apparatus that generates a plurality of tomographic images as a tomographic image group based on three-dimensional voxel data from the tomographic image database 200 , performs image processing, and displays them on the display device 300 . The image processing apparatus 100 is realized, for example, as a computer including a general CPU (Central Processing Unit), GPU (Graphics Processing Unit), RAM, and programs executed by these. The image processing apparatus 100 includes a tomographic image acquiring unit 101, a tomographic image holding unit 102, a skin line extracting unit 103, a mask data creating unit 104, a mask processing unit 105, and a display control unit 106, as shown in FIG.

<Tomographic image acquisition unit>
The tomographic image acquisition unit 101 is a circuit that acquires, from the tomographic image database 200, a tomographic image group including a plurality of tomographic images generated from three-dimensional voxel data relating to the breast of the subject.

FIG. 2 is a schematic diagram showing an overview of the relationship between the three-dimensional voxel data 400 and the tomographic image group 420. As shown in FIG. The three-dimensional voxel data 400 is data obtained by mapping the X-ray transmittance or the density calculated based on the X-ray transmittance in the breast of the subject on a three-dimensional rectangular coordinate. In the following description, the horizontal direction is defined as the x direction, the front-rear direction is defined as the y direction, and the vertical direction is defined as the z direction with respect to the subject. Also, the three-dimensional voxel data 400 is assumed to be data acquired in a state in which the breast is pressed in the z direction by two planes parallel to the xy plane. A tomographic image group 420 is a set of tomographic images generated by extracting the three-dimensional voxel data 400 from a plane 401 that is parallel to the xy plane perpendicular to the pressing direction during imaging. More specifically, each tomographic image is obtained by mapping on the plane 401 the X-ray transmittance or density at points existing on the plane 401 among the points forming the three-dimensional voxel data 400 . Here, a plurality of tomographic images obtained by changing the position of the plane 401 in the z direction, specifically, a plurality of tomographic images 410-1, 410-2, . . . , 410-n as shown in FIG. (n is any natural number) constitute the tomographic image group 420 . Note that the plurality of tomographic images 410-1, 410-2, . . . , 410-n have larger z coordinates on the plane 401 in this order. In the embodiment, the number of tomographic images (the value of n) in the group of tomographic images is 60. Any number is acceptable. Also, here, the three-dimensional voxel data is so-called CC (Cranio-Caudal direction), in which the breast is pressed in the z direction, and a tomographic image is generated in a direction parallel to the xy plane. When the dimensional voxel data is so-called MLO (Medio-Lateral Oblique), in which the breast is pressed according to the angle of the pectoralis major muscle, each tomographic image constituting the tomographic image group is perpendicular to the pressing direction. It may be a tomographic image along a plane parallel to the plane on which the image is taken.

The tomographic image acquiring unit 101 outputs the acquired tomographic image group 420 to the tomographic image holding unit 102 .

<Tomographic image holding unit>
The tomographic image holding unit 102 is a circuit that stores and holds a tomographic image group 420 composed of tomographic images 410-1, 410-2, . . . , 410-n. The tomographic image holding unit 102 is implemented by, for example, a semiconductor memory.

<Skin line extraction unit>
The skin line extraction unit 103 is a circuit that selects one or more tomographic images from the tomographic images forming the tomographic image group 420 and extracts skin lines from each of the tomographic images. In the embodiment, the skin line extraction unit 103 extracts a tomographic image 410-1 with the smallest z coordinate, a tomographic image 410-n with the largest z coordinate, and a tomographic image 410-(n/2 ).

The skin line extraction unit 103 extracts skin lines, which are skin images, from each of the selected tomographic images. A known technique can be used as a method for extracting skin lines. For example, histogram analysis of a tomographic image is performed to determine the brightness value of the skin line, which is the boundary between the breast region and the non-breast region, and the brightness value of the skin line is determined from the chest wall side. A method of searching for a pixel having the relevant luminance value on the papillary side can be used. Alternatively, for example, a Sobel filter is used to obtain contour data corresponding to a change in brightness between two pixels, the contour data is binarized, and the binarized contour data is subjected to convex hull processing to obtain skin lines. Extract. More specifically, a Sobel filter is used to extract regions where the luminance value (X-ray intensity) changes, and binarization is used to extract only regions where the degree of change in luminance value is equal to or greater than a threshold value, and contour extraction is performed. Alternatively, as disclosed in Patent Document 3, the skin line extraction unit 103 performs wavelet transform on a tomographic image, then inversely transforms only high-frequency components, performs a search based on pixel values, and extracts skin lines. good too.

The skin line extraction unit 103 outputs skin line data related to each selected tomographic image to the mask data creation unit 104 .

<<Mask data creation part>>
The mask data generation unit 104 is a circuit that determines an area (hereinafter referred to as a “mask”) to be subjected to darkening processing for each tomographic image forming the tomographic image group 420 based on the skin line data.

The mask data creation unit 104 identifies a tomographic image having the largest proportion of the breast region among a plurality of tomographic images from which skin lines have been extracted. Then, a mask is determined based on the identified skin lines of the tomographic image. As a method of determining the mask, for example, the entire non-breast area on the opposite side of the skin line to the chest wall can be set as the mask. Alternatively, for example, a preliminary region may be provided on the non-breast region side of the skin line, and a portion of the non-breast region excluding the preliminary region may be set as a mask. The preliminary area can be, for example, an area whose width in the y direction is about the width of the papilla in the y direction. As a result, masking of the breast region can be suppressed even when a partial image of the breast is located on the non-breast region side of the detected skin line. On the other hand, by not making the spare area excessively large, it is possible to secure the effect of improving the visibility by the darkening process.

The mask data creation unit 104 outputs mask data indicating the range of the created mask to the mask processing unit 105 .

<Mask processing part>
The mask processing unit 105 is a circuit that performs darkening processing on each tomographic image forming the tomographic image group 420 based on mask data.

The mask processing unit 105 acquires the tomographic images forming the tomographic image group 420 from the tomographic image holding unit 102 and the mask data from the mask data creating unit 104, and extracts the mask area specified by the mask data from the tomographic image. Darkening processing is performed on The darkening process is, for example, a process of filling the mask area with black or a single low-brightness color such as gray. Note that the darkening process is not limited to this, and may be a process of pasting a pattern such as hatching or tone, or a process of reducing the brightness of the mask area. However, filling with a single color or pasting a monotonous pattern is preferable in that it can clearly indicate to the user that it is a non-breast region that does not require interpretation.

The mask processing unit 105 outputs the tomographic image after the darkening processing to the display control unit 106 .

<Display control part>
The display control unit 106 is a circuit that causes the display device 300 to display the tomographic image after the darkening processing has been performed by the mask processing unit 105 .

<Other configurations>
Although not shown, the image processing apparatus 100 includes a control unit that controls each functional unit described above and an input unit that receives input from a user. The input unit is implemented by, for example, a keyboard, mouse, trackball, or the like. Note that the input unit may include a touch panel integrally formed with the display unit of the display device 300 .

≪Action≫
The operation of the image processing apparatus 100 will be described below with reference to the drawings. 3 is a schematic diagram showing the flow of data in the image processing apparatus 100, FIG. 4 is a schematic diagram showing the flow of processing in the image processing apparatus 100, and FIG.

First, the image processing apparatus 100 acquires a tomographic image group composed of a plurality of tomographic images based on three-dimensional voxel data in the tomographic image acquisition unit 101 (step S10). As described above, the tomographic image acquisition unit 101 acquires from the tomographic image database 200 a tomographic image group composed of tomographic images obtained by extracting three-dimensional voxel data from planes parallel to the xy plane at a plurality of z coordinates. In the embodiment, as shown in column _A of FIG. 4, a tomographic image 410-1 at z=0, a tomographic image 410-2 at z=1, . /2 ₎ , _. get a flock. The tomographic image based on the 3D voxel data is not a tomographic image obtained by tomographic imaging but a pseudo tomographic image generated by calculation, but only the intersection area between each of the parallel planes and the breast is tomographically imaged. can be regarded as a tomographic image. In this specification, there is no distinction between a tomographic image generated by imaging and a pseudo tomographic image generated by calculation, and both are simply referred to as "tomographic images".

Next, the skin line extraction unit 103 of the image processing apparatus 100 extracts a plurality of tomographic images from the group of tomographic images as reference tomographic images (step S20). In the embodiment, as shown in column B of FIG. 4, a tomographic image 410-1 with the smallest z-coordinate, a tomographic image 410-n with the largest z-coordinate, and a tomographic image 410-(n/2) with the central z-coordinate , are extracted as reference tomographic images.

Next, the image processing apparatus 100 extracts the skin line of each reference tomographic image in the skin line extraction unit 103, and specifies the reference tomographic image having the largest breast area.

First, after initializing the index i (step S31), the skin line extraction unit 103 extracts the skin line Li of the i-th reference tomographic image Pi and calculates the breast region area Si (step S32). Extraction of the skin line is performed, for example, by performing histogram analysis of the tomographic image, obtaining the brightness value of the skin line, which is the boundary between the breast region and the non-breast region, and obtaining the brightness value of the skin line as shown in FIG. , the search area 600 is searched from the chest wall side to the papillary side for pixels having the relevant luminance value. Alternatively, the skin line extraction unit 103 may obtain contour data corresponding to a change in brightness between two pixels using a Sobel filter, binarize the contour data, and perform convex hull processing on the binarized contour data. good. Alternatively, a method as disclosed in Patent Document 3 may be used. Specifically, after the tomographic image is wavelet-transformed, only high-frequency components are inverse-transformed, a pixel having the maximum pixel value is searched for each y-coordinate, and a threshold value is set based on the median value. Next, a first search is performed to search for the first pixel that exceeds the boundary value, which is the brightness value of the skin line, in the x direction, and a second search is performed using this pixel as a reference to extract the skin line.

Next, the skin line extraction unit calculates the breast region area Si using the extracted skin line Li as a reference. As shown in FIG. 6B, with the skin line 501 as a reference, the breast area 503 is on the chest wall side, and the non-breast area 502 is on the opposite side. can be calculated. As the breast region area Si, for example, the total number of pixels existing in the breast region 503 can be used. Then, by repeating the process of step S32 by the number of reference tomographic images Pi (steps S33 and S34), skin line extraction and breast region area calculation are performed for all reference tomographic images. Then, the value k of i of the reference tomographic image Pi having the largest breast area Si is specified (step S40). By this processing, one reference tomographic image Pk having the largest breast region area and the skin line Lk of the reference tomographic image Pk are determined as shown in column C of FIG.

Next, the image processing apparatus 100 sets the mask region M in the mask data generator 104 based on the skin line Sk of the reference tomographic image Pk (step S50). As a method of setting the mask area M, for example, as shown in FIG. Alternatively, for example, as shown in FIG. 7A, a preliminary region 620-1 is provided near the skin line 501-1 of the non-breast region 502-1, and the non-breast region 502-1 other than the preliminary region 620-1 is The region 630-1 may be used as the mask region 510 as shown in FIG. 7(b). The edge 610 that defines the preliminary region 620-1 can be determined, for example, by moving the skin line 501-1 to the side opposite to the chest wall (to the left in the figure) by a predetermined distance. Here, it is preferable that the predetermined distance is, for example, a very small amount such as the width of the image of the papilla. As a result of this processing, as shown in column D of FIG. 4, a mask region M based on one reference tomographic image Pk having the largest breast region area is determined.

Next, the image processing apparatus 100 initializes the frame number j of the tomographic image (step S61), darkens the mask region M of the tomographic image Tj of the tomographic image group, and displays it on the display device 300 (step S62). ). Specifically, the tomographic image Tj is acquired from the tomographic image holding unit 102 , the display color of the entire area included in the mask region M is changed to a single dark color (for example, black), and the resulting image is output to the display device 300 . As described above, the darkening process may be a change to a single gray, or replacement with hatching or tones. Then, an input from the user is received (step S63), and if there is an instruction to change the frame number j of the tomographic image, j is changed (step S64) and step S62 is executed again. As a result, all the tomographic images 410 included in the tomographic image group 420 are subjected to the darkening process using the same mask region M. Therefore, even if the display frame is changed, the mask region M can be reset. Tomographic images can be displayed at high speed without the need to

<Summary>
According to the above configuration, since a single mask area is used for a plurality of tomographic images included in a tomographic image group, there is no need to detect skin lines and set mask areas for each of the tomographic images. Therefore, tomographic images can be displayed at high speed. can be improved. Further, in the above configuration, the mask region is set based on the tomographic image having the largest breast region area among the plurality of tomographic images included in the tomographic image group. Multiple tomographic images included in the group of tomographic images have breast regions similar in position, range, and size. Since the portion corresponding to the breast region in the maximum tomographic image is not masked by the mask region, it is possible to reduce the possibility that the breast region will be masked by the mask region. Further, in the embodiment, a preliminary region in contact with the skin line is provided in the non-breast region, and the preliminary region is excluded from the mask region. According to this configuration, even if there is a tomographic image in which a part of the breast region exists in the non-breast region in the tomographic image with the largest breast region area, the possibility that the breast region is masked by the mask region is eliminated. can be reduced. Specifically, for example, as shown in FIG. 7C, a part of the skin line 502-2 in the tomographic image 450-2 is Even if it exists on the non-breast area side of the skin line 501-1, the chest wall side edge 610 of the mask area always exists on the non-breast area side of the skin line 501-1. not masked by

<<Generation of 3D voxel data>>
In the embodiment, the tomographic image database 200 already stores and stores a tomographic image group consisting of a plurality of tomographic images based on three-dimensional voxel data. , and a voxel data conversion device.

FIG. 8 is a schematic diagram of an imaging device. The imaging apparatus is, for example, an apparatus for capturing an X-ray tomographic image, and includes an imaging table 801 including an X-ray detection unit, a fixing unit 802 for fixing the breast of the subject in cooperation with the imaging table 801, and an X-ray detector. It has an arm 820 that holds the source 810 and a guide 830 that allows the X-ray source 810 to move in a circle around the subject's breast. Arm 820 is movable, for example, in a range of 50°. With this configuration, the imaging apparatus can capture a plurality of tomographic images with different X-ray transmission directions for the fixed breast of the subject.

FIG. 9 is a diagram for explaining the outline of the operation of the voxel data generation device. The voxel data creation device creates voxel data 900 based on the tomographic image 910 and the tomographic image 920 . Voxel data 900 corresponds to the subject's breast on the imaging table 801 , and tomographic images 910 and 920 are X-ray tomographic images of the subject's breast on the imaging table 801 . In the following, to simplify the explanation, the tomographic image 910 is obtained by imaging in which the X-ray transmission direction is the z direction, and the tomographic image 920 is obtained by imaging in which the X-ray transmission direction is the z direction. shall be deemed to have been obtained.

More specifically, the following processing is performed.

A pixel 911 on the tomographic image 910 corresponds to a rod-shaped region extending in the z-direction, which is the transmission direction of X-rays, in the subject's breast. Therefore, the integrated value of the X-ray attenuation rate of each of the plurality of pixels forming the region 911L in the voxel data 900 corresponding to the bar-shaped region is obtained from the luminance value (X-ray detection intensity) of the pixel 911 on the tomographic image 910. can be calculated. Similarly, a pixel 912 on the tomographic image 910 corresponds to a rod-shaped region extending in the z-direction, which is the transmission direction of X-rays, in the breast of the subject. The integrated value of the X-ray attenuation rate of each of the plurality of pixels forming 912L can be calculated from the luminance value (X-ray detection intensity) of pixel 912 on tomographic image 910 . Although only two pixels on the tomographic image 910 are shown in FIG. An integrated value of the X-ray attenuation factor of the pixels can be calculated.

Similarly, a pixel 921 on the tomographic image 920 corresponds to a rod-shaped region extending in the x-direction, which is the transmission direction of X-rays, in the breast of the subject. Therefore, the integrated value of the X-ray attenuation rate of each of the plurality of pixels forming the region 921L in the voxel data 900 corresponding to the bar-shaped region can be calculated from the luminance value of the pixel 921 on the tomographic image 920. FIG. Similarly, a pixel point 922 on the tomographic image 920 corresponds to a bar-shaped region extending in the x-direction, which is the transmission direction of X-rays, in the breast of the subject. The integrated value of the X-ray attenuation rate of each of the plurality of pixels forming the region 922L can be calculated from the luminance value (X-ray detection intensity) of the pixel 922 on the tomographic image 920 . Although only two pixels on the tomographic image 920 are shown in FIG. An integrated value of the X-ray attenuation factor of the pixels can be calculated.

The voxel data generation device reconstructs three-dimensional voxel data from a plurality of tomographic images based on the above data, using reconstruction technology disclosed in Patent Document 1, for example.

Although the X-ray transmission directions are different by 90° here, three-dimensional voxel data can be generated in the same manner by synthesizing a plurality of tomographic images of the same subject with different X-ray transmission directions. Formation is possible.

Based on the relationship between the three-dimensional voxel data and the tomographic image group described above, the voxel data conversion device cuts out the three-dimensional voxel data at each of a plurality of planes parallel to each other as shown in FIG. Images are generated and output as a group of tomographic images.

<<Other modifications according to the embodiment>>
(1) In the embodiments, the skin line extraction unit selects the tomographic images at both ends and the center in the z direction as reference tomographic images from a tomographic image group consisting of a plurality of tomographic images arranged in the z direction. However, the selection criteria for the reference tomographic images are not limited to this. A tomographic image may be selected every q (q is a natural number equal to or greater than 1). Alternatively, the reference tomographic images may not be evenly extracted in the z direction, for example, a large number of reference tomographic images may be extracted near the center in the z direction, and fewer reference tomographic images may be extracted in the vertical upper direction in the z direction. Alternatively, for example, only one of the tomographic images at both ends and the center in the z direction is selected, and the mask area is calculated based on the skin line of the selected one tomographic image without calculating the breast area area. You may decide.

Further, in the embodiment, a single mask region is set for all the tomographic images forming the tomographic image group. The darkening process may be performed based on the reference tomographic image that is closest to the tomographic image to be displayed when created and arranged in the z direction. Specifically, for example, 60 tomographic images are included in the tomographic image group, and the first, 30th, and 60th tomographic images arranged in the z direction are set as reference tomographic images. At this time, for the 1st to 15th tomographic images, darkening processing is performed by creating a mask region based on the 1st tomographic image, and for the 16th to 45th tomographic images, based on the 30th tomographic image. For the 46th to 60th tomographic images, a mask region is created based on the 60th tomographic image and darkening processing is performed. Alternatively, for example, three or more reference tomographic images are selected, and the tomographic image positioned between the two reference tomographic images when arranged in the z direction is the reference having the larger breast region area among the two reference tomographic images. A mask area may be set based on the tomographic image. Specifically, for example, 60 tomographic images are included in the tomographic image group, and the first, 30th, and 60th tomographic images arranged in the z direction are set as reference tomographic images. At this time, for the 1st to 30th tomographic images, darkening processing is performed by creating a mask area based on the tomographic image with the larger breast area area among the 1st tomographic image and the 30th tomographic image. For the 31st to 60th tomographic images, darkening processing is performed by creating a mask area based on the tomographic image with the larger breast area among the 30th and 60th tomographic images.

(2) In the embodiments, the image processing apparatus displays one tomographic image and changes the displayed tomographic image according to user input. However, for example, the image processing apparatus displays tomographic images after mask processing in the order in which they are arranged in the z-direction as a moving image or continuously displays them in a tomographic image group composed of a plurality of tomographic images arranged in the z-direction. You can do it.

(3) In the embodiment, for a tomographic image that is not selected as a reference tomographic image among tomographic images included in a tomographic image group, the image processing apparatus uses mask regions based on any of the selected reference tomographic images. darkening process. However, for example, after generating a mask region based on one of the selected reference tomographic images, skin line extraction is performed on all tomographic images to be displayed to generate mask regions and display them. If the generation of the mask region for the tomographic image has not been completed, darkening processing based on the mask region based on one of the selected reference tomographic images may be performed. Alternatively, for example, the image processing device displays tomographic images after mask processing in the order in which they are arranged in the z-direction as a moving image, or displays them continuously, for a tomographic image group composed of a plurality of tomographic images arranged in the z-direction. When one of the selected reference tomographic images is selected, the darkening process is performed based on the masked area, and when one tomographic image is selected and displayed, the darkening process is performed based on the masked area based on the selected tomographic image. may be performed.

(4) In the embodiment, the three-dimensional voxel data has a rectangular parallelepiped shape with the front-rear direction as the y-axis, the left-right direction as the x-axis, and the up-down direction as the z-axis as viewed from the subject. It is assumed that the images are cut planes by xy planes with different z coordinates. However, the shape of the three-dimensional voxel data is not limited to this. For example, the direction of compression of the breast may not be orthogonal to the plane of the tomographic image, and the tomographic image may be a parallelogram.

(5) In the embodiment, the image processing device acquires the tomographic image group composed of a plurality of tomographic images based on the three-dimensional voxel data. A tomographic image group may be generated from three-dimensional voxel data by the function of the voxel data conversion device. Further, the image display device and the tomographic image database may be arranged remotely and connected by VPN or the like, and similarly, the imaging device and the tomographic image database may be arranged remotely and connected by VPN or the like.

(6) Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and the following cases are also included in the present invention.

For example, in the present invention, the image processing device may be a device using FPGA (Field Programmable Gate Array) or ASIC (Application Specific Integrated Circuit) as a processor. Also, the image processing device and the display device may be implemented as a single device.

Also, part or all of the components constituting each of the devices described above may be configured from one system LSI (Large Scale Integration). A system LSI is an ultra-multifunctional LSI manufactured by integrating multiple components on a single chip. Specifically, it is a computer system that includes a microprocessor, ROM, RAM, etc. . These may be made into one chip individually, or may be made into one chip so as to include part or all of them. LSIs are also called ICs, system LSIs, super LSIs, and ultra LSIs depending on the degree of integration. The RAM stores a computer program that achieves the same operations as those of the above devices. The system LSI achieves its functions by the microprocessor operating according to the computer program. For example, the present invention includes a case where the user assistance method of the present invention is stored as an LSI program, and this LSI is inserted into a computer to execute a predetermined program.

It should be noted that the method of circuit integration is not limited to LSI, and may be implemented using a dedicated circuit or a general-purpose processor. A programmable FPGA or a reconfigurable processor capable of reconfiguring connections and settings of circuit cells inside the LSI may be used after the LSI is manufactured.

Furthermore, if an integration technology that replaces the LSI appears due to advances in semiconductor technology or another derived technology, the technology may naturally be used to integrate the functional blocks.

In the tomographic image database according to the above embodiment, the storage unit is included in the server, but the storage unit is not limited to this. may be connected from. Alternatively, the image display system may include a device including a storage unit or an alternative mechanism, such as a server computer having a file server function, independently of the tomographic image database.

Also, the division of functional blocks in the block diagram is an example, and a plurality of functional blocks can be realized as one functional block, one functional block can be divided into a plurality of functional blocks, and some functions can be moved to other functional blocks. may Also, a single piece of hardware or software may process functions of a plurality of functional blocks having similar functions in parallel or in a time-sharing manner.

Also, the order in which the above steps are performed is for illustrative purposes in order to specifically describe the present invention, and orders other than the above may be used. Also, some of the above steps may be executed concurrently (in parallel) with other steps.

Also, at least part of the functions of the image processing apparatus according to each embodiment and its modifications may be combined. Furthermore, the numbers used above are all examples for specifically describing the present invention, and the present invention is not limited to the numbers shown.

Furthermore, the present invention also includes various modifications in which those skilled in the art make modifications to the present embodiment.

≪Summary≫
(1) An image processing apparatus according to an embodiment is an image processing apparatus that displays a plurality of tomographic images on a display device. an acquisition unit, a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the tomographic image group, and a first skin line selected from the tomographic images in which the skin line detection unit detects skin lines. a mask setting unit that sets a mask region in the non-breast region of the first tomographic image based on the skin line of the tomographic image; and a second tomographic image different from the first tomographic image included in the group of tomographic images, and an image processing unit that darkens the same area as the mask area of the first tomographic image and displays it on a display device.

A display device according to an embodiment is a display device that displays a plurality of tomographic images, and includes an image acquisition unit that acquires a plurality of tomographic images acquired from a breast of a subject as a group of tomographic images; a skin line detection unit for detecting skin lines in a breast region from one or more tomographic images included in an image group; A mask setting unit that sets a mask region in a non-breast region of the first tomographic image, and a second tomographic image that is different from the first tomographic image included in the group of tomographic images, based on the first tomographic image. It is characterized by comprising an image processing unit that darkens the same region as the mask region, and a display unit that displays the second tomographic image after the darkening processing by the image processing unit.

Further, a tomographic image display system according to an embodiment is a tomographic image display system that displays a plurality of images based on three-dimensional voxel data, and includes a server device that holds three-dimensional voxel data and a display device, The display device includes a tomographic image conversion unit that acquires three-dimensional voxel data acquired from the breast of the subject from the server device and converts the data into a tomographic image group including a plurality of tomographic images, and a tomographic image conversion unit that is included in the tomographic image group. a skin line detection unit that detects skin lines in a breast region from one or more tomographic images; A mask setting unit for setting a mask region in a non-breast region of one tomographic image; It is characterized by including an image processing unit that performs darkening processing on an area, and a display unit that displays the second tomographic image after the darkening processing has been performed by the image processing unit.

Further, an image processing method according to an embodiment is an image processing method for displaying a plurality of tomographic images on a display device, wherein a plurality of tomographic images obtained from a breast of a subject are obtained as a tomographic image group, A skin line in a breast region is detected from one or more tomographic images included in a tomographic image group, and based on the skin line of the first tomographic image selected from the tomographic images in which the skin line has been detected, non-ablation of the first tomographic image is performed. setting a mask region in the breast region, and darkening the same region as the mask region of the first tomographic image in a second tomographic image different from the first tomographic image included in the group of tomographic images, and performing the display; It is characterized by displaying on the device.

Further, a program according to an embodiment is a program for causing a computer connected to a display device to perform image processing for displaying a plurality of tomographic images on a display device, wherein the image processing is obtained from a breast of a subject. a plurality of tomographic images are acquired as a tomographic image group, skin lines of a breast region are detected from one or more tomographic images included in the tomographic image group, and a first tomographic image selected from the tomographic images in which the skin lines are detected. setting a mask region in the non-breast region of the first tomographic image based on the skin line of the first tomographic image of a second tomographic image different from the first tomographic image included in the group of tomographic images; The processing is characterized in that the same region as the mask region is darkened and displayed on the display device.

According to the above configuration, the second tomographic image is darkened based on the skin line extraction result of the first tomographic image. Therefore, it is not necessary to perform skin line extraction processing on all the tomographic images forming the tomographic image group, and the amount of calculation can be reduced to improve the display speed of tomographic images.

(2) Further, the image processing apparatus of (1) acquires the plurality of tomographic images as three-dimensional voxel data, generates the tomographic image group from the three-dimensional voxel data, and outputs the tomographic image group to the image acquisition unit. A voxel data conversion unit may be further provided.

According to the above configuration, since the shape and size of the breast region are similar among the plurality of tomographic images forming the tomographic image group, it is possible to reduce the possibility that the mask region covers the breast region of the second tomographic image. can.

(3) In the image processing apparatus of (1) or (2) above, the skin line detection unit detects skin lines from the plurality of tomographic images, and the mask setting unit detects skin lines from the plurality of tomographic images. Among them, the tomographic image having the largest breast area may be selected as the first tomographic image.

According to the above configuration, the mask area is set based on the tomographic image having the largest area of the breast area among the tomographic images selected by the skin line detection unit. The possibility of being covered can be further reduced.

(4) Further, in the image processing apparatus of (3) above, the skin line detection unit detects the order when the tomographic images included in the tomographic image group are arranged so that the corresponding regions of the subject are aligned in one direction. may detect the skin lines of the tomographic image in the order of first, center, and last.

According to the above configuration, it is possible to reduce the possibility that the breast region of the second tomographic image is covered with the mask region while reducing the number of tomographic images to be subjected to skin line extraction processing.

(5) Further, in the image processing apparatus of (3) above, the skin line detection unit detects n Skin lines may be detected in every other tomographic image (where n is an integer equal to or greater than 1).

According to the above configuration, it is possible to reduce the possibility that the breast region of the second tomographic image is covered by the mask region while reducing the target of skin line extraction processing to an appropriate amount instead of the entire group of tomographic images.

(6) In the image processing apparatus of (1) or (2) above, the skin line detection unit arranges the tomographic images included in the tomographic image group so that the corresponding regions of the subject are aligned in one direction. The mask setting unit detects the skin line in the tomographic image whose order is first, middle, or last when the skin line detection unit detects the skin line in the first tomographic image. You can also select it as an image.

According to the above configuration, it is possible to reduce the possibility that the breast region of the second tomographic image is covered with the mask region while minimizing the amount of calculation for the skin line extraction process.

(7) Further, in the image processing apparatus of (1) to (6) above, the mask setting unit uses a non-breast region excluding a preliminary region close to the skin line as a mask region based on the skin line. It may be set.

According to the above configuration, even if the non-breast region of the first tomographic image and the breast region of the second tomographic image overlap each other, the breast region of the second tomographic image is prevented from being covered by the mask region. be able to.

(8) In the image processing apparatus of (1) to (6) above, the mask setting unit sets the entire area of the first tomographic image other than the breast area as a mask area based on the skin line. , may be

According to the above configuration, it is possible to maximize the target area of the darkening process and minimize the strain on the user's eyes.

(9) In the image processing apparatus according to (1) to (8) above, the image processing unit may fill the mask area with a single color as the darkening process.

According to the above configuration, the darkening process can be simplified to reduce the amount of calculation, and the non-breast area can be visually indicated to the user to assist diagnosis.

INDUSTRIAL APPLICABILITY The present disclosure is useful as a technique for reducing the user's burden in mammography interpretation, particularly in 3D mammography interpretation by tomosynthesis.

REFERENCE SIGNS LIST 100 image processing apparatus 101 tomographic image acquiring unit 102 tomographic image holding unit 103 skin line extracting unit 104 mask data creating unit 105 mask processing unit 106 display control unit 200 tomographic image database 300 display device 1000 image display system

Claims (16)

An image processing device for displaying a plurality of tomographic images on a display device,
an image acquisition unit that acquires a plurality of tomographic images acquired from the breast of the subject as a group of tomographic images;
a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the group of tomographic images;
a mask setting unit that sets a mask area in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line detection unit has detected the skin line;
an image processing unit that darkens the same region as the mask region of the first tomographic image of a second tomographic image that is different from the first tomographic image included in the group of tomographic images, and displays the result on a display device; prepared,
The skin line detection unit detects skin lines from the plurality of tomographic images,
The image processing apparatus, wherein the mask setting unit selects a tomographic image having a largest breast area from among the plurality of tomographic images as the first tomographic image. An image processing device for displaying a plurality of tomographic images on a display device,
an image acquisition unit that acquires a plurality of tomographic images acquired from the breast of the subject as a group of tomographic images;
a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the group of tomographic images;
a mask setting unit that sets a mask area in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line detection unit has detected the skin line;
an image processing unit that darkens the same region as the mask region of the first tomographic image of a second tomographic image that is different from the first tomographic image included in the group of tomographic images, and displays the result on a display device; prepared,
The skin line detection unit selects a tomographic image whose order is first, center, or last when the tomographic images included in the group of tomographic images are arranged so that the corresponding regions of the subject are aligned in one direction. detect skin lines,
The image processing apparatus, wherein the mask setting unit selects the tomographic image from which the skin line is detected by the skin line detecting unit as the first tomographic image. 2. A voxel data conversion unit that acquires the plurality of tomographic images as three-dimensional voxel data, generates the group of tomographic images from the three-dimensional voxel data, and outputs the group of tomographic images to the image acquisition unit. 3. The image processing apparatus according to 2. The skin line detection unit detects the skin lines of the tomographic images that are first, center, and last when the tomographic images included in the group of tomographic images are arranged so that the corresponding regions of the subject are aligned in one direction. The image processing apparatus according to claim 1, characterized by detecting: The skin line detection unit detects tomographic images that are every n (where n is an integer equal to or greater than 1) when the tomographic images included in the tomographic image group are arranged so that the corresponding regions of the subject are aligned in one direction. The image processing apparatus according to claim 1, wherein skin lines are detected. 6. The mask setting unit according to any one of claims 1 to 5, wherein the mask setting unit sets a non-breast area excluding a preliminary area close to the skin line as a mask area based on the skin line. image processing device. The image according to any one of claims 1 to 5, wherein the mask setting unit sets the entire area of the first tomographic image other than the breast area as the mask area based on the skin line. processing equipment. The image processing apparatus according to any one of claims 1 to 7, wherein the image processing section fills the mask area with a single color as the darkening process. A display device for displaying a plurality of tomographic images,
an image acquisition unit that acquires a plurality of tomographic images acquired from the breast of the subject as a group of tomographic images;
a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the group of tomographic images;
a mask setting unit that sets a mask area in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line detection unit has detected the skin line;
an image processing unit that darkens the same region as the mask region of the first tomographic image of a second tomographic image that is different from the first tomographic image included in the group of tomographic images;
a display unit that displays the second tomographic image after the darkening process has been performed by the image processing unit;
The skin line detection unit detects skin lines from the plurality of tomographic images,
The display device, wherein the mask setting unit selects, from among the plurality of tomographic images, a tomographic image having a largest breast region area as the first tomographic image. A display device for displaying a plurality of tomographic images,
an image acquisition unit that acquires a plurality of tomographic images acquired from the breast of the subject as a group of tomographic images;
a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the group of tomographic images;
a mask setting unit that sets a mask area in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line detection unit has detected the skin line;
an image processing unit that darkens the same region as the mask region of the first tomographic image of a second tomographic image that is different from the first tomographic image included in the group of tomographic images;
a display unit that displays the second tomographic image after the darkening process has been performed by the image processing unit;
The skin line detection unit selects a tomographic image whose order is first, center, or last when the tomographic images included in the group of tomographic images are arranged so that the corresponding regions of the subject are aligned in one direction. detect skin lines,
The display device, wherein the mask setting unit selects the tomographic image from which the skin line is detected by the skin line detecting unit as the first tomographic image. A tomographic image display system that displays a plurality of images based on three-dimensional voxel data,
A server device that holds three-dimensional voxel data, and a display device, wherein the display device
a tomographic image conversion unit that acquires three-dimensional voxel data obtained from a breast of a subject from the server device and converts the data into a tomographic image group composed of a plurality of tomographic images;
a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the group of tomographic images;
a mask setting unit that sets a mask area in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line detection unit has detected the skin line;
an image processing unit that darkens the same region as the mask region of the first tomographic image of a second tomographic image that is different from the first tomographic image included in the group of tomographic images;
a display unit that displays the second tomographic image after the darkening process has been performed by the image processing unit;
The skin line detection unit detects skin lines from the plurality of tomographic images,
The tomographic image display system, wherein the mask setting unit selects, from among the plurality of tomographic images, a tomographic image having a largest breast region area as the first tomographic image. A tomographic image display system that displays a plurality of images based on three-dimensional voxel data,
A server device that holds three-dimensional voxel data, and a display device, wherein the display device
a tomographic image conversion unit that acquires three-dimensional voxel data obtained from a breast of a subject from the server device and converts the data into a tomographic image group composed of a plurality of tomographic images;
a skin line detection unit that detects skin lines in a breast region from one or more tomographic images included in the group of tomographic images;
a mask setting unit that sets a mask area in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line detection unit has detected the skin line;
an image processing unit that darkens the same region as the mask region of the first tomographic image of a second tomographic image that is different from the first tomographic image included in the group of tomographic images;
a display unit that displays the second tomographic image after the darkening process has been performed by the image processing unit;
The skin line detection unit selects a tomographic image whose order is first, center, or last when the tomographic images included in the group of tomographic images are arranged so that the corresponding regions of the subject are aligned in one direction. detect skin lines,
The tomographic image display system, wherein the mask setting unit selects the tomographic image from which the skin line is detected by the skin line detecting unit as the first tomographic image. An image processing method for displaying a plurality of tomographic images on a display device,
Acquiring a plurality of tomographic images obtained from the breast of the subject as a tomographic image group,
detecting a skin line of a breast region from one or more tomographic images included in the tomographic image group;
setting a mask region in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line is detected;
darkening the same region as the mask region of the first tomographic image of a second tomographic image different from the first tomographic image included in the group of tomographic images and displaying the same on the display device;
When detecting the skin line, the skin line is detected from a plurality of the tomographic images,
An image processing method, wherein when setting the mask region, a tomographic image having a largest breast region area is selected from among the plurality of tomographic images as a first tomographic image. An image processing method for displaying a plurality of tomographic images on a display device,
Acquiring a plurality of tomographic images obtained from the breast of the subject as a tomographic image group,
detecting a skin line of a breast region from one or more tomographic images included in the tomographic image group;
setting a mask region in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line is detected;
darkening the same region as the mask region of the first tomographic image of a second tomographic image different from the first tomographic image included in the group of tomographic images and displaying the same on the display device;
When detecting the skin line, the tomographic images included in the tomographic image group are arranged in the first, middle, or last order when the corresponding regions of the subject are arranged in one direction. detect the skin lines of
An image processing method, wherein, when setting the mask region, a tomographic image from which the skin line is detected is selected as the first tomographic image. A program for causing a computer connected to a display device to perform image processing for displaying a plurality of tomographic images on the display device,
The image processing includes
Acquiring a plurality of tomographic images obtained from the breast of the subject as a tomographic image group,
detecting a skin line of a breast region from one or more tomographic images included in the tomographic image group;
setting a mask region in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line is detected;
a process of darkening the same region as the mask region of the first tomographic image of a second tomographic image different from the first tomographic image included in the tomographic image group and displaying the masked region on the display device;
When detecting the skin line, the skin line is detected from a plurality of the tomographic images,
A program, wherein, when setting the mask region, a tomographic image having a largest breast region area is selected from among the plurality of tomographic images as a first tomographic image. A program for causing a computer connected to a display device to perform image processing for displaying a plurality of tomographic images on the display device,
The image processing includes
Acquiring a plurality of tomographic images obtained from the breast of the subject as a tomographic image group,
detecting a skin line of a breast region from one or more tomographic images included in the tomographic image group;
setting a mask region in a non-breast region of the first tomographic image based on the skin line of the first tomographic image selected from the tomographic images in which the skin line is detected;
a process of darkening the same region as the mask region of the first tomographic image of a second tomographic image different from the first tomographic image included in the tomographic image group and displaying the masked region on the display device;
When detecting the skin line, the tomographic images included in the tomographic image group are arranged in the first, middle, or last order when the corresponding regions of the subject are arranged in one direction. detect the skin lines of
A program, wherein when setting the mask region, a tomographic image from which the skin line is detected is selected as the first tomographic image.

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