A CPU acquires a distance image which indicates a distance to an imaging target and is captured by a TOF camera that captures the distance image using, as the imaging target, a mammography apparatus which is an abnormality determination target. In addition, the CPU acquires reference distance image as reference distance information related to a reference value of a distance between the abnormality determination target in a reference state and the TOF camera. Further, the CPU performs determination on an abnormality appearing in an outward appearance of the abnormality determination target on the basis of the distance image and the reference distance image.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2020-065267, filed on Mar. 31, 2020. The above application is hereby expressly incorporated by reference, in its entirety, into the present application.

BACKGROUND

1. Technical Field

The present disclosure relates to an information processing apparatus, an information processing method, and an information processing program.

2. Description of the Related Art

A technique is known which supports the capture of a radiographic image by a radiography apparatus using a distance image showing the distance to an imaging target. For example, JP2014-511731A discloses a technique which provides a 3D free space model for moving a moving portion without collision, using a depth image captured by a time-of-flight camera.

SUMMARY

It is desirable to perform determination on an abnormality occurring in the outward appearance of a mammography apparatus as the support for the capture of the radiographic image. However, it is difficult for the technique described in JP2014-511731A to perform the determination on the abnormality.

The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide an information processing apparatus, an information processing method, and an information processing program that can perform determination on an abnormality occurring in the outward appearance of a mammography apparatus from a distance image.

In order to achieve the above object, according to a first aspect of the present disclosure, there is provided an information processing apparatus comprising: at least one processor; and a memory that stores commands executable by the processor. The processor acquires a distance image which indicates a distance to an imaging target and is captured by a distance image capture device that captures the distance image using, as the imaging target, a mammography apparatus which is an abnormality determination target, acquires reference distance information related to a reference value of a distance between the abnormality determination target in a reference state and the distance image capture device, and performs determination on an abnormality appearing in an outward appearance of the abnormality determination target on the basis of the distance image and the reference distance information.

According to a second aspect of the present disclosure, in the information processing apparatus according to the first aspect, the processor may determine that the abnormality has occurred in a case in which an absolute value of a difference between a distance to the abnormality determination target indicated by the distance image and the reference value is greater than an abnormality determination threshold value.

According to a third aspect of the present disclosure, in the information processing apparatus according to the second aspect, in a case in which it is determined that the abnormality has occurred, the processor may determine that, as the absolute value of the difference becomes larger, a degree of the abnormality becomes larger.

According to a fourth aspect of the present disclosure, in the information processing apparatus according to the second aspect, the processor may specify an abnormal region that is greater than the abnormality determination threshold value in the distance image, and may determine that deflection has occurred as the abnormality in a case in which a width of the specified abnormal region is equal to or greater than a type determination threshold value.

According to a fifth aspect of the present disclosure, in the information processing apparatus according to the second aspect, the processor may specify an abnormal region that is greater than the abnormality determination threshold value in the distance image, and may determine that a scratch or a crack has occurred as the abnormality in a case in which a width of the specified abnormal region is less than a type determination threshold value.

According to a sixth aspect of the present disclosure, in the information processing apparatus according to the second aspect, the abnormality determination target may be at least one of a plurality of components in the mammography apparatus, and the abnormality determination threshold value may be determined for each of the plurality of components.

According to a seventh aspect of the present disclosure, in the information processing apparatus according to the first aspect, the abnormality determination target may be at least one of a plurality of components in the mammography apparatus, and the reference distance information may be determined for each of the plurality of components.

According to an eighth aspect of the present disclosure, in the information processing apparatus according to the sixth aspect, the plurality of components may be provided with marks including portions having different distances from the distance image capture device, and the processor may determine which of the plurality of components is the abnormality determination target from an image of the mark in the distance image.

According to a ninth aspect of the present disclosure, in the information processing apparatus according to the first aspect, the processor may acquire a visible light image of the abnormality determination target captured by a visible light image capture device that captures the visible light image, acquire a reference visible light image obtained by capturing an image of the abnormality determination target in the reference state, and perform determination on the abnormality appearing in the outward appearance of the mammography apparatus on the basis of the distance image, the reference distance information, the visible light image, and the reference visible light image.

According to a tenth aspect of the present disclosure, in the information processing apparatus according to the ninth aspect, in a case in which it is determined that no abnormality has occurred in the outward appearance of the mammography apparatus on the basis of the distance image and the reference distance information and that an abnormality has occurred in the outward appearance of the mammography apparatus on the basis of the visible light image and the reference visible light image, the processor may determine that a stain has occurred as the abnormality.

According to an eleventh aspect of the present disclosure, in the information processing apparatus according to the first aspect, the reference distance information may be a reference distance image indicating a distance between the distance image capture device and the abnormality determination target disposed at a reference position.

According to a twelfth aspect of the present disclosure, in the information processing apparatus according to the eleventh aspect, in a case in which the abnormality determination target is not disposed at the reference position, after moving the abnormality determination target to the reference position, the processor may direct the distance image capture device to capture the distance image, and acquire the distance image captured by the distance image capture device.

According to a thirteenth aspect of the present disclosure, in the information processing apparatus according to the first aspect, the abnormality may be at least one of a scratch, a crack, deflection, or a stain.

According to a fourteenth aspect of the present disclosure, in the information processing apparatus according to the first aspect, the abnormality determination target may be a compression member that is attached to the mammography apparatus.

According to a fifteenth aspect of the present disclosure, in the information processing apparatus according to the first aspect, the abnormality determination target may be an imaging table of the mammography apparatus.

According to a sixteenth aspect of the present disclosure, in the information processing apparatus according to the first aspect, the abnormality determination target may be a biopsy-related member that is attached to the mammography apparatus.

According to a seventeenth aspect of the present disclosure, in the information processing apparatus according to the first aspect, the distance image capture device may capture the distance image using a time-of-flight (TOF) method.

Further, in order to achieve the above object, according to an eighteenth aspect of the present disclosure, there is provided an information processing method execute by a computer, the method comprising: acquiring a distance image which indicates a distance to an imaging target and is captured by a distance image capture device that captures the distance image using, as the imaging target, a mammography apparatus which is an abnormality determination target; acquiring reference distance information related to a reference value of a distance between the abnormality determination target in a reference state and the distance image capture device; and performing determination on an abnormality appearing in an outward appearance of the abnormality determination target on the basis of the distance image and the reference distance information.

Furthermore, in order to achieve the above object, according to a nineteenth aspect of the present disclosure, there is provided a non-transitory computer-readable storage medium storing an information processing program that causes a computer to perform a process comprising: acquiring a distance image which indicates a distance to an imaging target and is captured by a distance image capture device that captures the distance image using, as the imaging target, a mammography apparatus which is an abnormality determination target; acquiring reference distance information related to a reference value of a distance between the abnormality determination target in a reference state and the distance image capture device; and performing determination on an abnormality appearing in an outward appearance of the abnormality determination target on the basis of the distance image and the reference distance information.

According to the present disclosure, it is possible to perform determination on an abnormality occurring in the outward appearance of a mammography apparatus from a distance image.

DETAILED DESCRIPTION

Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. Each of the embodiments does not limit the invention.

First Embodiment

First, an example of the overall configuration of a radiography system according to an embodiment will be described.FIG.1is a diagram illustrating an example of the overall configuration of a radiography system1according to this embodiment. As illustrated inFIG.1, the radiography system1according to this embodiment comprises a mammography apparatus10and a console12. The console12according to this embodiment is an example of an information processing apparatus according to the present disclosure.

First, the mammography apparatus10according to this embodiment will be described.FIG.2is a side view illustrating an example of the outward appearance of the mammography apparatus10according to this embodiment. In addition,FIG.2illustrates an example of the outward appearance of the mammography apparatus10as viewed from the right side of a subject.

The mammography apparatus10according to this embodiment irradiates the breast of the subject as an object with radiation R (for example, X-rays) to capture a radiographic image of the breast. In addition, the mammography apparatus10may be an apparatus that captures the image of the breast of the subject not only in a state in which the subject stands up (standing state) but also in a state in which the subject sits on, for example, a chair (including a wheelchair) (sitting state).

As illustrated inFIG.2, the mammography apparatus10according to this embodiment comprises a control unit20, a storage unit22, and an interface (I/F) unit24which are provided in an imaging table30. The control unit20controls the overall operation of the mammography apparatus10under the control of the console12. The control unit20comprises a central processing unit (CPU), a read only memory (ROM), and a random access memory (RAM) which are not illustrated. For example, various programs including an imaging processing program which is executed by the CPU and is used to perform control related to the capture of radiographic images are stored in the ROM in advance. The RAM temporarily stores various kinds of data.

For example, image data of the radiographic image captured by a radiation detector28and various other kinds of information are stored in the storage unit22. Examples of the storage unit22include a hard disk drive (HDD) and a solid state drive (SSD). The I/F unit24transmits and receives various kinds of information to and from the console12using wireless communication or wired communication. The image data of the radiographic image captured by the radiation detector28in the mammography apparatus10is transmitted to the console12through the I/F unit24by wireless communication or wired communication.

In addition, an operation unit26is provided as a plurality of switches in, for example, the imaging table30of the mammography apparatus10. Further, the operation unit26may be provided as a touch panel switch or may be provided as a foot switch that is operated by the user's feet.

The radiation detector28detects the radiation R transmitted through the breast which is the object. As illustrated inFIG.2, the radiation detector28is disposed in the imaging table30. In the mammography apparatus10according to this embodiment, in a case in which imaging is performed, the breast of the subject is positioned on an imaging surface30A of the imaging table30by a user such as a doctor or a radiology technician.

The radiation detector28detects the radiation R transmitted through the breast of the subject and the imaging table30, generates a radiographic image on the basis of the detected radiation R, and outputs image data indicating the generated radiographic image. The type of the radiation detector28according to this embodiment is not particularly limited. For example, the radiation detector28may be an indirect-conversion-type radiation detector that converts the radiation R into light and converts the converted light into charge or a direct-conversion-type radiation detector that directly converts the radiation R into charge.

A radiation emitting unit37comprises a radiation source37R. As illustrated inFIG.2, the radiation emitting unit37is provided in an arm portion32together with the imaging table30and a compression unit36. As illustrated inFIG.2, a face guard38is detachably attached to a position of the arm portion32which is close to the subject below the radiation emitting unit37.

In addition, a visible light camera31and a time-of-flight (TOF) camera39are provided at a position of the arm portion32which is away from the subject below the radiation emitting unit37. The visible light camera31is a so-called general camera and captures a visible light image. The visible light camera31according to this embodiment is an example of a visible light image capture device according to the present disclosure. Specifically, the visible light camera31receives visible light reflected by an imaging target and captures a visible light image on the basis of the received visible light.

The TOF camera39is a camera that captures a distance image indicating a distance to the imaging target using a TOF method. The TOF camera39according to this embodiment is an example of a distance image capture device according to the present disclosure. Specifically, the TOF camera39emits light, such as infrared rays, to the imaging target and measures the distance between the TOF camera39and the imaging target on the basis of the time until reflected light is received or a phase change between the emitted light and the received light. In the distance image captured by the TOF camera39, each pixel has distance information indicating the distance between the TOF camera39and the imaging target. Further, the distance image is an image from which the distance to the imaging target can be derived.

In addition, the imaging target in this embodiment is the mammography apparatus10whose abnormality is to be determined (hereinafter, referred to as an “abnormality determination target”), which will be described in detail below. The abnormality determination target is not limited to the entire mammography apparatus10, and may be a part, such as the imaging table30, or a component, such as a compression plate40, in the mammography apparatus10. Therefore, a region including the abnormality determination target is an imaging region of the TOF camera39. In addition, in the TOF camera39and the visible light camera31, the imaging targets are the same, but the imaging regions may not be exactly the same.

In addition, as illustrated inFIG.2, the mammography apparatus10according to this embodiment comprises the arm portion32, a base34, and a shaft portion35. The arm portion32is held by the base34so as to be movable in the up-down direction (Z-axis direction). The shaft portion35connects the arm portion32to the base34. In addition, the arm portion32can be relatively rotated with respect to the base34, using the shaft portion35as a rotation axis.

Each of the arm portion32and the compression unit36can be relatively rotated with respect to the base34, using the shaft portion35as a rotation axis. In this embodiment, gears (not illustrated) are provided in each of the shaft portion35, the arm portion32, and the compression unit36. Each gear is switched between an engaged state and a disengaged state to connect each of the arm portion32and the compression unit36to the shaft portion35. One or both of the arm portion32and the compression unit36connected to the shaft portion35are rotated integrally with the shaft portion35.

The compression unit36is provided with a compression plate driving unit (not illustrated) that moves a compression plate40in the up-down direction (Z-axis direction). The compression plate40according to this embodiment has a function of compressing the breast of the subject. A support portion46of the compression plate40is detachably attached to the compression plate driving unit and is moved in the up-down direction (Z-axis direction) by the compression plate driving unit to compress the breast of the subject between the compression plate40and the imaging table30. The compression plate40according to this embodiment is an example of a compression member according to the present disclosure.

There are a plurality of types of compression plates40that can be attached to the mammography apparatus10according to this embodiment. In this example, the compression plate40compresses the entire breast. However, the present disclosure is not limited thereto. For example, a compression plate40that compresses a portion of the breast may be used. In other words, the compression plate40may be smaller than the breast. For example, as the compression plate40, a compression plate40is known which is used for so-called spot imaging that captures a radiographic image of only the region in which a lesion is present. Further, other types of compression plates40include, for example, a compression plate corresponding to the size of the breast, a compression plate for axillary imaging, and a compression plate for magnification imaging.

As a specific example, the compression plate40attached to the mammography apparatus10according to this embodiment will be described with reference toFIG.3.FIG.3is a three-view diagram illustrating an example of the compression plate40according to this embodiment. The three-view diagram illustrated inFIG.3includes a plan view (top view) of the compression plate40viewed from the upper side (from the radiation emitting unit37), a side view of the compression plate40viewed from the subject, and a side view of the compression plate40viewed from the right side of the subject. As illustrated inFIG.3, the compression plate40according to this embodiment includes a compression portion42and a support portion46.

The compression portion42is formed in a concave shape in a cross-sectional view in which a bottom portion43is surrounded by a wall portion44. In the bottom portion43, the thickness of a plate having a surface that comes into contact with the breast of the subject is substantially constant. It is preferable that the compression portion42is optically transparent in order to check positioning or a compressed state in the compression of the breast. In addition, the compression portion42is made of a material having high transmittance for the radiation R. Specific examples of the material include polycarbonate (PC) and polyethylene terephthalate (PRT), acrylic, and polypropylene (PP). However, the material is not particularly limited.

On the other hand, the support portion46includes an attachment portion47and an arm48. The attachment portion47has a function of attaching the compression plate40to the mammography apparatus10, specifically, the compression plate driving unit in the compression plate40. The arm48has a function of supporting the compression portion42.

The console12according to this embodiment has a function of controlling the mammography apparatus10using, for example, an imaging order and various kinds of information acquired from a radiology information system (RIS)2through a wireless communication local area network (LAN) and instructions input by the user through an operation unit56or the like.

For example, the console12according to this embodiment is a server computer. As illustrated inFIG.4, the console12comprises a control unit50, a storage unit52, an I/F unit54, the operation unit56, and a display unit58. The control unit50, the storage unit52, the I/F unit54, the operation unit56, and the display unit58are connected to each other through a bus59, such as a system bus or a control bus, such that they can transmit and receive various kinds of information.

The control unit50according to this embodiment controls the overall operation of the console12. The control unit50comprises a CPU50A, a ROM50B, and a RAM50C. For example, various programs including an abnormality determination processing program51executed by the CPU50A are stored in the ROM50B in advance. The RAM50C temporarily stores various kinds of data. The CPU50A according to this embodiment is an example of a processor according to the present disclosure, and the ROM50B according to this embodiment is an example of a memory according to the present disclosure. Further, the abnormality determination processing program51according to this embodiment is an example of an information processing program according to the present disclosure.

For example, the image data of the radiographic image captured by the mammography apparatus10and various other kinds of information are stored in the storage unit52. An HDD or an SSD is given as a specific example of the storage unit52. Further, the storage unit52according to this embodiment stores reference distance information53which will be described in detail below.

The operation unit56is used by the user to input, for example, instructions which are related to the capture of a radiographic image and include an instruction to emit the radiation R or various kinds of information. The operation unit56is not particularly limited. Examples of the operation unit56include various switches, a touch panel, a touch pen, and a mouse. The display unit58displays various kinds of information. In addition, the operation unit56and the display unit58may be integrated into a touch panel display.

The I/F unit54transmits and receives various kinds of information between the mammography apparatus10and the RIS2using wireless communication or wired communication. In the radiography system1according to this embodiment, the console12receives the image data of the radiographic image captured by the mammography apparatus10from the mammography apparatus10through the I/F unit54, using wireless communication or wired communication.

FIG.5is a functional block diagram illustrating an example of the configuration of the console12according to this embodiment. As illustrated inFIG.5, the console12comprises a first acquisition unit60, a second acquisition unit62, and a determination unit64. For example, in the console12according to this embodiment, the CPU50A of the control unit50executes the abnormality determination processing program51stored in the ROM50B to function as the first acquisition unit60, the second acquisition unit62, and the determination unit64.

The first acquisition unit60has a function of acquiring the distance image captured by the TOF camera39. For example, the first acquisition unit60according to this embodiment acquires image data indicating the distance image captured by the TOF camera39from the TOF camera39through the I/F unit24and the I/F unit54.

In addition, the first acquisition unit60has a function of acquiring the visible light image captured by the visible light camera31. For example, the first acquisition unit60according to this embodiment acquires image data indicating the visible light image captured by the visible light camera31from the visible light camera31through the I/F unit24and the I/F unit54.

The second acquisition unit62has a function of acquiring the reference distance information53. For example, the second acquisition unit62according to this embodiment acquires the reference distance information53from the storage unit52. The reference distance information53is information related to a reference value of the distance between the abnormality determination target and the TOF camera39in a state in which the abnormality determination target in a reference state is disposed at a reference position. For example, in a case in which the abnormality determination target is the compression plate40, the reference distance information53is information related to the reference value of the distance between the TOF camera39and the compression plate40in an initial state which is attached to the initial position of the mammography apparatus10. In addition, an example of the initial position in the disposition of the compression plate40is the position where the compression plate40is closest to the imaging table30. Further, an example of the initial state of the compression plate40is an unused state. Furthermore, an example of the reference distance information53is a distance image captured by the TOF camera39. Hereinafter, the distance image as the reference distance information53is referred to as a reference distance image53A.

In addition, the second acquisition unit62has a function of acquiring a reference visible light image55. For example, the second acquisition unit62according to this embodiment acquires the reference visible light image55from the storage unit52. The reference visible light image55is a visible light image captured by the visible light camera31in a state in which the abnormality determination target in the reference state is disposed at the reference position. In addition, the reference state and the reference position in this case are the same as the reference state and the reference position for the reference distance information53.

As described above, in this embodiment, the aspect in which the reference distance information53and the reference visible light image55are stored in the storage unit52of the console12has been described. However, the place in which the reference distance information53and the reference visible light image55are stored is not limited to the storage unit52. For example, the reference distance information53and the reference visible light image55may be stored in the storage unit22of the mammography apparatus10or may be stored in a device outside the radiography system1. In addition, the reference distance information53and the reference visible light image55may be stored in different devices.

Further, in this embodiment, in a case in which the mammography apparatus10which is the abnormality determination target is described with a specific example, the compression plate40will be described as an example. In this case, the reference distance information53is the reference distance image53A captured by the TOF camera39in a state in which the unused compression plate40is attached to the mammography apparatus10for the first time and is disposed at the position closest to the imaging table30. Further, the reference visible light image55is the reference visible light image captured by the visible light camera31in a state in which the unused compression plate40is attached to the mammography apparatus10for the first time and is disposed at the position closest to the imaging table30.

The determination unit64has a function of determining an abnormality appearing in the outward appearance of the mammography apparatus10on the basis of the distance image, the reference distance information53, the visible light image, and the reference visible light image55. In addition, the abnormality determination target may not be the entire mammography apparatus10and may be parts or components (hereinafter, simply referred to as “components”) of the mammography apparatus10such as the compression plate40, the imaging table30, a biopsy-related member, and the face guard. Further, in a case in which the abnormality determination target is a component of the mammography apparatus10, a plurality of components may be the abnormality determination targets. For example, both the compression plate40and the imaging table30may be the abnormality determination targets. In this case, the images of the compression plate40and the imaging table30as the abnormality determination targets are simultaneously captured, which makes it possible to determine abnormalities for a plurality of abnormality determination targets using one distance image.

Here, a method for determining an abnormality appearing in the outward appearance of the mammography apparatus10on the basis of the distance image, the reference distance information53, the visible light image, and the reference visible light image55in the determination unit64according to this embodiment will be described. The determination unit64according to this embodiment determines whether or not an abnormality, such as a scratch, a crack, deflection, or a stain, has occurred as an example of the abnormality appearing in the outward appearance of the mammography apparatus10(hereinafter, simply referred to as an “abnormality”). In a case in which the abnormality has occurred, the determination unit64determines the position where the abnormality has occurred.

FIG.6Aillustrates an example of a visible light image70and a distance image72obtained by capturing a state in which no abnormality occurs. The visible light image70does not include an image showing a scratch, a crack, deflection, and a stain which are abnormalities. Further, the distance image72does not show any abnormality. As such, in a case in which no abnormality has occurred in the abnormality determination target, the distance image72is a distance image showing the distance to the abnormality determination target. For example, in a case in which the abnormality determination target is a flat plate, the distance to the abnormality determination target is uniform. Therefore, the distance image72is an image in which pixel values are substantially uniform.

FIG.6Billustrates an example of a visible light image70A and a distance image72A obtained by capturing a state in which a scratch or a crack occurs. The visible light image70A includes a crack image80and a scratch image81. Further, inFIG.6B, the crack image80and the scratch image81are represented by dotted lines. However, the crack image80and the scratch image81are represented by the dotted lines for convenience of illustration and are not the images of the crack and scratch on the dotted lines. The specific conditions of the crack and the scratch do not matter. Furthermore, the distance image72A includes an abnormal region82corresponding to the crack and an abnormal region83corresponding to the scratch.

In a case in which there is a crack or a scratch, the infrared rays emitted to the abnormality determination target in the capture of the distance image by the TOF camera39are diffusely reflected by the crack or the scratch and do not accurately reach the TOF camera39. As a result, in a portion corresponding to the crack or scratch, the distance to the abnormality determination target measured by the TOF camera39tends to be longer than the actual distance. Therefore, in the portion corresponding to the crack or scratch, the distance measured by the TOF camera39tends to be longer than the distance measured in a case in which the abnormality determination target is in the normal state. In addition, the distance to the portion corresponding to the crack or scratch is longer than the distance to a portion in the normal state which is present around the crack or the scratch.

FIG.6Cillustrates an example of a visible light image70B and a distance image72B obtained by capturing a state in which deflection occurs. The deflection may also be distortion and is accompanied by deformation such as plastic deformation in the abnormality determination target. However, as in the visible light image70B, a visible light image may not show deformation caused by the deflection. In contrast, in the distance image72B, a region deformed by the deflection appears as an abnormal region84. For example, in a case in which the entire compression portion42of the compression plate40is deflected as illustrated inFIG.6C, the distance image72B obtained by capturing the bottom portion43includes the abnormal region84corresponding to the deflection.

In a case in which the compression portion42is deformed in a direction in which it becomes closer to the TOF camera39due to the deflection, the distance between the abnormality determination target and the TOF camera39is shorter than the distance measured in the normal state in which the deformation caused by the deflection does not occur. On the contrary, in a case in which the compression portion42is deformed in a direction in which it becomes further away from the TOF camera39due to the deflection, the distance between the abnormality determination target and the TOF camera39is longer than the distance measured in the normal state in which the deformation caused by the deflection does not occur.

In addition, in a case in which the compression portion42is deformed in a direction parallel to the TOF camera39, the position of a feature point of the abnormality determination target in the height direction, that is, a feature point in the distance to the TOF camera39changes. For example, in a case in which the bottom portion43of the compression plate40(seeFIG.3) changes from a rectangle to a parallelogram, the position of the wall portion44which is a feature point changes. Therefore, in a portion corresponding to the position of the wall portion44before and after the deformation caused by the deflection, the distance between the abnormality determination target and the TOF camera39is longer or shorter than the distance measured in the normal state in which the deformation caused by the deflection does not occur.

As such, the distance images72A and72B show the abnormal regions82,83, and84corresponding to the abnormalities, regardless of whether the abnormality is a crack, a scratch, or deflection. However, the abnormal region caused by the deflection tends to be larger and wider than the abnormal region caused by the crack and the abnormal region caused by the scratch. In many cases, cracks and scratches occur linearly. In this case, as illustrated inFIG.6B, the abnormal regions82and83are long and thin regions. Assuming that directions intersecting the length directions of the long abnormal regions82and83are widths W1and W2, respectively, each of the widths W1and W2is smaller than a width W3(seeFIG.6C) of the abnormal region84caused by the deflection.

Therefore, in a case in which the determination unit64according to this embodiment has compared the distance image captured by the TOF camera39with the reference distance image53A and specified an abnormal region from the distance image, it determines that any abnormality of a crack, a scratch, or deflection has occurred. Specifically, in a case in which the absolute value of a difference between the distance indicated by the distance image and the distance indicated by the reference distance image53A is greater than an abnormality determination threshold value, that is, in a case in which the amount of change in the distance to the TOF camera39is large, the determination unit64according to this embodiment determines that any abnormality of a crack, a scratch, or deflection has occurred. More specifically, in a case in which the absolute value of a difference between the pixel value of a pixel in the distance image and the pixel value of a pixel in the reference distance image53A is greater than the abnormality determination threshold value, the determination unit64determines that any abnormality of a crack, a scratch, or deflection has occurred. In addition, for example, a value which has been experimentally obtained using the distance images obtained by capturing various cracks, scratches, deflections, and the like with the TOF camera39in consideration of a normal state, errors, or the like can be used as the abnormality determination threshold value.

Further, in a case in which the width of the abnormal region is equal to or greater than a type determination threshold value, the determination unit64according to this embodiment determines that the type of abnormality which has occurred is deflection. On the other hand, in a case in which the width of the abnormal region is less than the type determination threshold value, the determination unit64determines that the type of the abnormal surface which has occurred is a crack or a scratch. In addition, for example, a value which has been experimentally obtained on the basis of the width of the abnormal region caused by the crack or the scratch included in the distance image obtained by capturing various cracks, scratches, deflections, and the like with the TOF camera39and the width of the abnormal region caused by the deflection can be used as the type determination threshold value.

FIG.6Dillustrates an example of a visible light image70C and a distance image72C obtained by capturing a state in which a stain occurs. The visible light image70C includes a stain image85. In contrast, the distance image72C does not include an abnormal region regardless of the stain. The stain that occurs in the abnormality determination target does not cause unevenness on the surface. Alternatively, even in a case in which unevenness occurs, it is relatively little. Therefore, in a portion corresponding to the stain, the distance measured by the TOF camera39tends to be substantially the same as the distance measured in a case in which the abnormality determination target is in the normal state, and a change in the distance between the abnormality determination target and the TOF camera39tends to be smaller than that at least in a case in which the other abnormalities have occurred.

Therefore, the determination unit64according to this embodiment determines that a stain has occurred as an abnormality in a case in which the result of the comparison between the distance image captured by the TOF camera39and the reference distance image53A shows that the distance image does not include an abnormal region and the result of the comparison between the visible light image captured by the visible light camera31and the reference visible light image55shows that an abnormality has occurred. Specifically, the determination unit64according to this embodiment determines that no cracks, scratches, and deflections have occurred as abnormalities in a case in which the absolute value of the difference between the distance represented by the distance image and the distance represented by the reference distance image53A is equal to or less than the abnormality determination threshold value, that is, the amount of change in the distance to the TOF camera39is small. Further, in the determination unit64determines that a stain has occurred as an abnormality in a case in which the number of consecutive pixels satisfying the condition that the absolute value of the difference between the pixel value of the pixel in the visible light image and the pixel value of the pixel in the reference visible light image55is greater than a stain determination threshold value, is equal to or greater than a value required for stain determination. In this case, the region of the stain image85in the visible light image70C is an abnormal region.

Further, the determination unit64according to this embodiment determines that no abnormalities have occurred in a case in which the result of the comparison between the distance image captured by the TOF camera39and the reference distance image53A shows that an abnormal region is not included in the distance image and the result of the comparison between the visible light image captured by the visible light camera31and the reference visible light image55shows that there is no abnormality.

Next, the operation of the console12according to this embodiment will be described with reference to the drawings.

In the console12according to this embodiment, the CPU50A of the control unit50executes the abnormality determination processing program51stored in the ROM50B to perform an abnormality determination process whose example is illustrated inFIG.7.FIG.7is a flowchart illustrating an example of the flow of the abnormality determination process performed in the console12according to this embodiment. In addition, the timing when the CPU50A performs the abnormality determination process is not limited, and the CPU50A may perform the abnormality determination process at any timing. For example, the CPU50A may perform the abnormality determination process whenever a predetermined time has elapsed since the first operation of the mammography apparatus10, the timing when the mammography apparatus10is turned on, or the timing when an instruction issued by the user through the operation unit56is received. Further, for example, in the case of the compression plate40, the CPU50A may perform the abnormality determination process at the timing when the compression plate40is attached to the mammography apparatus10.

In Step S100ofFIG.7, the first acquisition unit60acquires a distance image from the TOF camera39of the mammography apparatus10. Specifically, the first acquisition unit60instructs the TOF camera39to capture a distance image and acquires the distance image captured by the TOF camera39on the basis of the instruction through the I/F unit24. The distance image acquired by the first acquisition unit60is output to the determination unit64.

In addition, in a case in which the abnormality determination target is not disposed at the reference position at this timing, it is preferable that the determination unit64moves the abnormality determination target to the reference position and then instructs the TOF camera39to capture a distance image. For example, in a case in which the abnormality determination target is the compression plate40, the determination unit64specifies the position of the attachment portion47attached to the compression unit36to specify the current position of the compression plate40. In a case in which the current position is not the reference position, the determination unit64instructs the mammography apparatus10to move the compression plate40to the reference position. The control unit20of the mammography apparatus10that has received the instruction moves the compression plate40to the reference position using the compression unit36. After checking that the current position of the compression plate40is the reference position, the determination unit64instructs the TOF camera39to capture a distance image.

Then, in Step S102, the second acquisition unit62acquires the reference distance information53from the storage unit52. As described above, in this embodiment, the reference distance image53A is adopted as the reference distance information53. Therefore, the reference distance image53A is acquired from the storage unit52. The acquired reference distance image53A is output to the determination unit64.

Then, in Step S104, the determination unit64derives the difference between the distance image and the reference distance image53A. Specifically, as described above, for the pixels at the corresponding positions, the difference between the pixel value of the pixel in the distance image and the pixel value of the pixel in the reference distance image53A is derived.

Then, in Step S106, as described above, the determination unit64determines whether or not the absolute value of the difference derived in the Step S104is greater than the abnormality determination threshold value (|difference|>the abnormality determination threshold value). In a case in which the absolute value of the difference is greater than the abnormality determination threshold value, the determination result in Step S106is “Yes”, and the process proceeds to Step S108.

In Step S108, the determination unit64derives the width of the abnormal region as described above. Then, in Step S110, as described above, the determination unit64determines whether or not the width of the abnormal region derived in Step S108is equal to or greater than the type determination threshold value (the width≥the type determination threshold value). In a case in which the width of the abnormal region is not equal to or greater than the type determination threshold value, that is, in a case in which the width of the abnormal region is less than the type determination threshold value, the determination result in Step S110is “No”, and the process proceeds to Step S112. As described above, the determination unit64determines that a crack or a scratch has occurred as an abnormality in Step S112and then proceeds to Step S128.

On the other hand, in a case in which the width of the abnormal region is equal to or greater than the type determination threshold value in Step S110, the determination result is “Yes”, and the process proceeds to Step S114. As described above, the determination unit64determines that deflection has occurred as an abnormality in Step S114and then proceeds to Step S128.

Further, in a case in which the absolute value of the difference derived in Step S104is not greater than the abnormality determination threshold value, that is, in a case in which the absolute value of the difference is equal to or less than the abnormality determination threshold value in Step S106, the determination result in Step S106is “No”, and the process proceeds to Step S116.

In Step S116, the first acquisition unit60acquires a visible light image from the visible light camera31of the mammography apparatus10. Specifically, the first acquisition unit60instructs the visible light camera31to capture a visible light image and acquires the visible light image captured by the visible light camera31on the basis of the instruction through the I/F unit24. The visible light image acquired by the first acquisition unit60is output to the determination unit64.

Then, in Step S118, the second acquisition unit62acquires the reference visible light image55from the storage unit52. As described above, the acquired reference visible light image55is output to the determination unit64. Then, in Step S120, the determination unit64compares the visible light image with the reference visible light image as described above.

Then, in Step S122, the determination unit64determines whether or not an abnormal region is included in the visible light image as described above. In a case in which an abnormal region is included in the visible light image, the determination result in Step S122is “Yes”, and the process proceeds to Step S124. In Step S124, as described above the determination unit64determines that a stain has occurred as an abnormality and then proceeds to Step S128.

On the other hand, in a case in which an abnormal region is not included in the visible light image in Step S122, the determination result is “No”, and the process proceeds to Step S126. In Step S126, as described above, the determination unit64determines that no abnormality has occurred and then proceeds to Step S128.

In Step S128, the determination unit64outputs the determination result and the position of the abnormal region. Specifically, the determination unit64outputs any of the determination results in Steps S112, S114, S124, and S126. Further, the determination unit64outputs the position of the abnormal region in a case in which the determination results in Steps S112, S114, and S124are output. In addition, the output aspect of the position of the abnormal region is not particularly limited. For example, an image obtained by adding information indicating the position of a specified abnormal region to the visible light image may be output. Furthermore, the output destination of the determination results and the position of the abnormal region by the determination unit64is not particularly limited. For example, the output destination may be the display unit58of the console12, the mammography apparatus10, or other apparatuses. In a case in which the process in Step S128ends in this way, the abnormality determination process illustrated inFIG.7ends.

The present disclosure is not limited to this aspect. The timing when the TOF camera39captures the distance image, the timing when the visible light camera31captures the visible light image, and the timing when the CPU50A performs the abnormality determination process may not be synchronized with each other. For example, the TOF camera39may capture the distance image at any timing. The visible light camera31may capture the visible light image. The distance image and the visible light image may be stored in the storage unit22. The CPU50A may acquire the distance image and the visible light image stored in the storage unit22and perform the abnormality determination process at any another timing.

As described above, in a case in which the abnormality is any of a crack, a scratch, or deflection, the abnormality appears as an abnormal region in the distance image. In addition, in a case in which the abnormality is a stain, the abnormality appears in the visible light image. Therefore, in this embodiment, the console12acquires the distance image captured by the TOF camera39and the visible light image captured by the visible light camera31and determines an abnormality occurring in the outward appearance of the mammography apparatus10which is the abnormality determination target, on the basis of the distance image, the reference distance image53A, the visible light image, and the reference visible light image55. Therefore, the console12according to this embodiment can determine an abnormality occurring in the outward appearance of the mammography apparatus from the distance image.

Second Embodiment

As described above, the mammography apparatus10has a plurality of components, and each of the plurality of components can be used as the abnormality determination target. As such, in a case in which each of the plurality of components is used as the abnormality determination target, the normal state and the degree of occurrence of abnormalities may vary depending on the components. Therefore, in this embodiment, an aspect in which abnormality determination is performed on each of the plurality of components will be described. For a mammography apparatus10and a console12according to this embodiment, the detailed description of the same configuration and operation as those in the first embodiment will not be repeated.

Since the overall configuration of the mammography apparatus10and the console12according to this embodiment is the same as that in the first embodiment, the description of the overall configuration will not be repeated. In the mammography apparatus10according to this embodiment, identification information for identifying each abnormality determination target is given to each abnormality determination target.FIG.8illustrates an example of the compression plate40to which identification information90is given. In the compression plate40illustrated inFIG.8, the identification information90is provided at a position that faces the radiation emitting unit37in the arm48that extends from the attachment portion47. The identification information90is information for identifying the compression plate. Further, there are a plurality of types of compression plates40that can be attached to the mammography apparatus10according to this embodiment. Therefore, the identification information90is also information for identifying the type of the compression plate40. Moreover, even in a case in which the same components and the same type are used, the normal state may vary depending on each component. In this case, the identification information90may be identification information for identifying each component, or different identification information items90may be given to the components.

In this embodiment, for example, the identification information90given to the abnormality determination target is read from the visible light image captured by the visible light camera31. Therefore, the position where the identification information90is given to the abnormality determination target is a position in the imaging region of the visible light camera31and is a position where the identification information90is given to the visible light camera31. Further, as described above, the normal state and the degree of occurrence of abnormalities may vary depending on the components. Therefore, in this embodiment, the abnormality determination threshold value is provided for each component which is the abnormality determination target. Therefore, in this embodiment, the abnormality determination threshold value associated with the identification information90is stored in the storage unit22(not illustrated).

Further, in this embodiment, the reference distance image53A and the reference visible light image55are also stored for each abnormality determination target in the storage unit52. Specifically, a plurality of reference distance images53A and reference visible light images55associated with each identification information item90are stored in the storage unit22of the console12.

In addition, since the operation of the console12, specifically, the abnormality determination process is different from that in the first embodiment, the abnormality determination process performed by the console12according to this embodiment will be described.

FIG.9is a flowchart illustrating an example of the flow of the abnormality determination process performed in the console12according to this embodiment. As illustrated inFIG.9, the abnormality determination process according to this embodiment includes a process in Steps S103A to S103C instead of Step S102in the abnormality determination process (seeFIG.7) according to the first embodiment.

In Step S103A illustrated inFIG.9, the first acquisition unit60acquires a visible light image from the visible light camera31of the mammography apparatus10in the same manner as in Step S116of the abnormality determination process (seeFIG.7) according to the first embodiment. Further, in the abnormality determination process according to this embodiment, the visible light image is acquired at this timing. Therefore, as illustrated inFIG.9, the abnormality determination process according to this embodiment does not include the process in Step S116which is a step for acquiring the visible light image in the abnormality determination process (seeFIG.7) according to the first embodiment.

Then, in Step S103B, the determination unit64reads the identification information from the visible light image. In addition, a method for reading the identification information from the visible light image in the determination unit64is not particularly limited. For example, in a case in which the identification information is a number or a letter like the identification information90illustrated inFIG.8, the determination unit64may perform image analysis for reading the number or the letter on the visible light image and read the number or the letter from the image of a portion corresponding to the abnormality determination target to read the identification information90.

Then, in Step S103C, the determination unit64acquires the reference distance image53A corresponding to the identification information read in Step S103B from the storage unit22. In the subsequent process, the reference distance image53A acquired in this step is used for abnormality determination.

Further, as illustrated inFIG.9, the abnormality determination process according to this embodiment includes a process in Step S105between the process in Step S104and the process in Step S106of the abnormality determination process (seeFIG.7) according to the first embodiment.

In Step S105, the determination unit64acquires an abnormality determination threshold value corresponding to the identification information read in Step S103B from the storage unit22. In the subsequent process, the abnormality determination threshold value acquired in this step is used for abnormality determination.

In this embodiment, the aspect in which identification information, such as the identification information90, for identifying the abnormality determination target is read from the visible light image has been described. However, a method for reading the identification information is not limited to this embodiment. For example, as illustrated inFIG.10, in a case in which identification information91that has an uneven shape toward the TOF camera39is provided in the abnormality determination target (the compression plate40inFIG.10), the identification information may be read from the distance image captured by the TOF camera39. The identification information91in this embodiment is an example of a mark according to the present disclosure. In the abnormality determination process in this case, instead of the process in Step S103A illustrated inFIG.9, Step S116of the abnormality determination process (seeFIG.7) according to the first embodiment may be performed. In addition, in Step S103, the identification information may be read from the distance image.

As described above, the console12according to each of the above-described embodiments comprises the CPU50A as at least one processor and the ROM50B storing commands that can be executed by the CPU50A. The CPU50A acquires the distance image captured by the TOF camera39, which captures a distance image showing the distance to the imaging target, using the mammography apparatus10which is the abnormality determination target as the imaging target. In addition, the CPU50A acquires the reference distance image53A as the reference distance information53related to the reference value of the distance between the abnormality determination target in the reference state and the TOF camera39. Further, the CPU50A determines an abnormality appearing in the outward appearance of the abnormality determination target on the basis of the distance image and the reference distance image53A.

The above-mentioned configuration makes it possible for the console12according to each of the above-described embodiments to determine an abnormality occurring in the outward appearance of the mammography apparatus10from the distance image.

Further, according to the console12of this embodiment, one distance image can be captured using a plurality of abnormality determination targets as the imaging targets, and abnormality determination can be performed on the plurality of abnormality determination targets on the basis of one distance image. Therefore, according to the console12of each of the above-described embodiments, abnormality determination can be performed more easily, as compared to a case in which abnormality determination needs to be performed on each abnormality determination target, for example, a case in which a sensor or the like for abnormality determination is provided for each abnormality determination target.

In addition, in each of the above-described embodiments, for abnormality determination on each abnormality determination target, the aspect in which whether or not an abnormality has occurred, the type of the abnormality that has occurred, and the position where the abnormality has occurred are determined has been described. However, the types of determination related to abnormalities are not limited to the above. For example, the degree of abnormality may be determined. For example, a degree determination threshold value for determining the degree of abnormality may be provided, and it may be determined that the degree of abnormality becomes larger as the threshold value for the above-mentioned difference becomes larger.

Further, in each of the above-described embodiments, the aspect in which the reference distance image53A is used as the reference distance information53has been described. However, the reference distance information53is not limited to the reference distance image53A. For example, the reference distance information53may be a reference value based on the design value of the abnormality determination target, the design value and the set value of the radiography system1, or the like.

Furthermore, in each of the above-described embodiments, the aspect in which the distance image is captured by the TOF method using the TOF camera has been described as an example of the aspect of capturing the distance image. However, the distance image capture device for capturing the distance image is not limited to the TOF camera. For example, the following aspect may be used: a distance image capture device that irradiates an imaging target with infrared light having a pattern and captures a distance image corresponding to reflected light from the imaging target is used, and a structured light method is applied to capture the distance image. Further, for example, a depth-from-defocus (DFD) method that restores the distance on the basis of the degree of blurring of an edge region in the distance image may be applied. In the case of this aspect, for example, an aspect is known which uses a distance image captured by a monocular camera using a color aperture filter.

Further, in each of the above-described embodiments, the aspect has been described in which the TOF camera39and the visible light camera31are provided on the side close to the compression unit36in the radiation emitting unit37of the mammography apparatus10. However, the position where each of the TOF camera39and the visible light camera31is provided is not limited to this aspect. Each of the TOF camera39and the visible light camera31may be disposed at any position where it can capture images using, as an imaging region, the entire mammography apparatus10or a region including a component. The position is not limited. For example, at least one of the TOF camera39or the visible light camera31may be provided on the side close to the face guard38in the radiation emitting unit37. In addition, for example, at least one of the TOF camera39or the visible light camera31may be provided outside the mammography apparatus10.

Further, in each of the above-described embodiments, the aspect in which the console12is an example of the information processing apparatus according to the present disclosure has been described. However, apparatuses other than the console12may have the functions of the information processing apparatus according to the present disclosure. In other words, for example, the mammography apparatus10or an external apparatus other than the console12may have some or all of the functions of the first acquisition unit60, the second acquisition unit62, and the determination unit64.

In each of the above-described embodiments, for example, the following various processors can be used as the hardware structure of processing units performing various processes such as the first acquisition unit60, the second acquisition unit62, and the determination unit64. The various processors include, for example, a programmable logic device (PLD), such as a field programmable gate array (FPGA), that is a processor whose circuit configuration can be changed after manufacture and a dedicated electric circuit, such as an application specific integrated circuit (ASIC), that is a processor having a dedicated circuit configuration designed to perform a specific process, in addition to the CPU that is a general-purpose processor which executes software (program) to function as various processing units as described above.

One processing unit may be configured by one of the various processors or a combination of two or more processors of the same type or different types (for example, a combination of a plurality of FPGAs or a combination of a CPU and an FPGA). In addition, a plurality of processing units may be configured by one processor.

A first example of the configuration in which a plurality of processing units are configured by one processor is an aspect in which one processor is configured by a combination of one or more CPUs and software and functions as a plurality of processing units. A representative example of this aspect is a client computer or a server computer. A second example of the configuration is an aspect in which a processor that implements the functions of the entire system including a plurality of processing units using one integrated circuit (IC) chip is used. A representative example of this aspect is a system-on-chip (SoC). As such, various processing units are configured by using one or more of the various processors as a hardware structure.

In addition, specifically, an electric circuit (circuitry) obtained by combining circuit elements, such as semiconductor elements, can be used as the hardware structure of the various processors.

In each of the above-described embodiments, the aspect in which the abnormality determination processing program51is stored (installed) in the storage unit52in advance has been described. However, the present disclosure is not limited thereto. The abnormality determination processing program51may be recorded on a recording medium, such as a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), or a universal serial bus (USB) memory, and then provided. In addition, the abnormality determination processing program51may be downloaded from an external apparatus through the network.