Depth measurement device, depth measurement method and depth measurement program

Abstract

To provide a depth measurement device, a depth measurement method and a depth measurement program capable of suppressing deterioration of measurement precision due to deviation of the relative positional relation of a detector with a radiation source.SOLUTION: A depth measurement device, etc. including a radiation source and a detector that is fixed relative to the radiation source, directly faces the radiation source and detects radiation: acquires a first picked-up image that images an object located at a first position away from the radiation source in a depth direction by a first distance and away from the radiation source in a direction along a detection surface of the detector by a second distance; acquires a second picked-up image that images the object located at a second position away from the radiation source in the depth direction by the first distance and away from the radiation source in the direction along the detection surface of the detector by a third distance; identifies a deviation amount of the object between the first picked-up image and the second picked-up image; and calculates the first distance on the basis of a fixed distance, the difference between the second distance and the third distance, and the deviation amount.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a depth measurement device, a depth measurement method, and a depth measurement program, and more particularly to a depth measurement device, a depth measurement method, and a depth measurement program that measure using radiation. [Background technology]

[0002] Conventionally, radiation has been used to obtain internal information of an object through images. Among these, tomosynthesis technology is becoming increasingly popular. Tomosynthesis technology obtains internal information of an object with high accuracy by reconstructing multiple projection images obtained by varying the radiation irradiation angle onto the object.

[0003] For example, the tomographic image generating device disclosed in Patent Document 1 performs tomosynthesis imaging by moving a radiation source relative to the detection surface of a detector and irradiating a subject with radiation at multiple positions of the radiation source due to the movement of the radiation source. The tomographic image generating device disclosed in Patent Document 1 is said to be able to obtain high-quality tomographic images of the subject.

[0004] However, in the tomographic image generating device disclosed in Patent Document 1, the radiation source is moved relative to the detection surface of the detector, and therefore the relative positional relationship between the radiation source and the detector when acquiring multiple projection images in tomosynthesis technology changes each time a projection image is acquired, which could be a factor that reduces the accuracy of the acquired tomographic images of the subject.

[0005] Furthermore, even in depth measurement devices that use tomosynthesis technology to measure the depth of an object inside a subject, the configuration in which the radiation source is moved relative to the detection surface of the detector could be one of the factors that reduces the accuracy of the measured depth, as with the tomographic image generation device disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Re-tabled publication No. 2020-067475 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to provide a depth measurement device, a depth measurement method, and a depth measurement program that suppress a decrease in measurement accuracy caused by a deviation in the relative positional relationship between a radiation source and a detector. [Means for solving the problem]

[0008] That is, the depth measurement device of the first aspect is characterized by comprising: a radiation source that emits radiation; a detector that faces the radiation source at a fixed distance and detects the radiation emitted by the radiation source; a first acquisition unit that acquires a first captured image of an object located at a first position where the distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and the distance from the radiation source in a direction along the detection surface of the detector is a second distance; a second acquisition unit that acquires a second captured image of an object located at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; an identification unit that identifies an amount of deviation between the object included in the first captured image and the object included in the second captured image; and a calculation unit that calculates the first distance based on the fixed distance, the difference between the second distance and the third distance, and the amount of deviation.

[0009] A second aspect may be a depth measurement device according to the first aspect, further comprising a movement mechanism that moves the radiation source and the detector in the same direction along the detection surface of the detector while maintaining a fixed distance, and the difference may be the movement distance from the position of the radiation source when the first captured image is captured to the position of the radiation source when the second captured image is captured.

[0010] In a third aspect, in the depth measurement device of the second aspect, the moving mechanism may be a robot arm that moves a connecting member connecting a radiation source and a detector that are facing each other at a fixed distance in a direction along the detection surface of the detector.

[0011] A fourth aspect is a depth measurement device according to the first aspect, which includes a movement mechanism that fixes the positions of the radiation source and the detector and moves the object between the radiation source and the detector in a direction along the detection surface of the detector, and the difference may be the movement distance from the position of the object when the first captured image is taken to the position of the object when the second captured image is taken.

[0012] As a fifth aspect, in the depth measurement device according to any one of the first to fourth aspects, the calculation unit may calculate the first distance by dividing the difference by the amount of deviation and multiplying the result by a fixed distance.

[0013] As a sixth aspect, the depth measurement device according to the fifth aspect may further include an output section that outputs the first distance.

[0014] A depth measurement method according to a seventh aspect is characterized in that a computer capable of communicating with a radiation source that emits radiation and a detector that faces the radiation source at a fixed distance and detects the radiation emitted by the radiation source executes the following steps: a first acquisition step of acquiring a first captured image of an object located at a first position where the distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and the distance from the radiation source in a direction along the detection surface of the detector is a second distance; a second acquisition step of acquiring a second captured image of an object located at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; an identification step of identifying an amount of deviation between the object included in the first captured image and the object included in the second captured image; and a calculation step of calculating the first distance based on the fixed distance, a difference between the second distance and the third distance, and the amount of deviation.

[0015] A depth measurement program according to an eighth aspect is characterized in that it causes a computer capable of communicating with a radiation source that emits radiation and a detector that faces the radiation source at a fixed distance and detects the radiation emitted by the radiation source to implement the following: a first acquisition function that acquires a first captured image of an object located at a first position where the distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and the distance from the radiation source in a direction along the detection surface of the detector is a second distance; a second acquisition function that acquires a second captured image of an object located at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; an identification function that identifies an amount of deviation between the object included in the first captured image and the object included in the second captured image; and a calculation function that calculates the first distance based on the fixed distance, a difference between the second distance and the third distance, and the amount of deviation. [Effects of the Invention]

[0016] The depth measurement device of the present invention is characterized by comprising: a radiation source that emits radiation; a detector that faces the radiation source at a fixed distance and detects the radiation emitted by the radiation source; a first acquisition unit that acquires a first captured image of an object located at a first position where the distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and the distance from the radiation source in a direction along the detection surface of the detector is a second distance; a second acquisition unit that acquires a second captured image of an object located at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; an identification unit that identifies an amount of deviation between the object included in the first captured image and the object included in the second captured image; and a calculation unit that calculates the first distance based on the fixed distance, the difference between the second distance and the third distance, and the amount of deviation.Therefore, it is possible to suppress a decrease in measurement accuracy caused by a deviation in the relative positional relationship between the radiation source and the detector. Additionally, the depth measurement method and depth measurement program according to the present invention can also similarly suppress a decrease in measurement accuracy caused by a deviation in the relative positional relationship between the radiation source and the detector. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram for explaining an overview of the depth measurement device according to this embodiment. [Figure 2] FIG. 2 is a block diagram for explaining an example of the hardware configuration of the depth measurement device according to this embodiment. [Figure 3] FIG. 3 is an example of a flowchart of an imaging method for depth measurement by the depth measurement device according to this embodiment. [Figure 4] FIG. 4 is a diagram for explaining the relationship between a plurality of positions and a plurality of distances when obtaining the mathematical formula for calculating the first distance (L1) of the depth measurement device according to this embodiment. [Figure 5] FIG. 5 is a diagram for explaining measurement of the amount of deviation (X) of the depth measurement device according to this embodiment. [Figure 6] FIG. 6 is a block diagram for explaining an example of the functional configuration of the depth measurement device according to this embodiment. [Figure 7] FIG. 7 is an example of a flowchart of the depth measurement program according to this embodiment. [Figure 8] FIG. 8 is an example of a flowchart of a depth measurement program according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] (Overview of the depth measurement device 10) A depth measurement device 10 according to one embodiment of the present disclosure will be described with reference to FIGS. First, with reference to FIG. 1, an overview of a depth measurement device 10 according to this embodiment will be described. FIG. 1 is a diagram for explaining an overview of a depth measurement device 10. As shown in FIG. The depth measurement device 10 includes a radiation source 7 that emits radiation 4 and a detector 8 that detects the radiation 4 emitted by the radiation source 7. The depth measurement device 10 is a device that irradiates the subject 1 with radiation 4 and measures the depth of an object 9 (see FIG. 4) inside the subject 1, and may be a so-called computer. The detector 8 faces the radiation source 7 at a fixed distance (L: see FIG. 4) and detects the radiation 4 emitted by the radiation source 7. The depth is the distance from the radiation source 7 to the object 9 in the depth direction from the radiation source 7 toward the detector 8 (Y direction in FIG. 4), and refers to the first distance L1 (see FIG. 4). Radiation 4 refers to particle radiation, which is material particles flowing with high kinetic energy, and electromagnetic radiation, which is high-energy electromagnetic waves. Particle radiation includes, for example, alpha rays, beta rays, neutron rays, and proton rays. Electromagnetic radiation includes, for example, gamma rays and X-rays. Directly facing refers to a state in which the radiation source 7 and the detection surface 8c of the detector 8 face each other directly. The fixed distance (L) refers to the distance between the radiation source 7 and the detection surface 8c of the detector 8 when the radiation source 7 and the detection surface 8c of the detector 8 are facing each other.

[0019] The specimen 1 may include components made of metal, non-metallic material, organic material, etc. Non-metallic materials include, for example, ceramics, glass, cement, stone, clay, manganese, graphite, etc. Organic materials include, for example, plastic, rubber, wood, paper, oil, and fat. The subject 1 is supported by a fixture 3 and placed on a base 2 . The object 9 is a member or space that exists inside the subject 1 and has a different radiation transmittance than the subject 1. The space includes gaps, cracks, bubbles, etc. that occur inside the subject 1. The object 9 in this embodiment is a space that exists inside the subject 1, but is not limited to this. The radiation source 7 and the detector 8 are attached to a connecting member 6 attached to the tip of the robot arm 5. The connecting member 6 is a C-shaped attachment to the robot arm 5, and is U-shaped, with the radiation source 7 attached to one side of the U-shape and the detector 8 attached to the other side. The fixed distance (L) between the radiation source 7 and the detector 8 can be adjusted by extending or shortening the length of the arm of the C-shaped attachment. Before and after the movement of the radiation source 7 and the detector 8, the relative positions of the radiation source 7 and the detector 8 are always the same, and the fixed distance (L) is also the same. The robot arm 5 is a type of industrial robot that functions like a human arm, and the operation of the robot arm 5 is controlled by the depth measurement device 10. The robot arm 5 includes, for example, a vertical articulated robot, a horizontal articulated robot, a parallel link robot, and an orthogonal robot. A C-type attachment is a type of robot hand (or end effector).

[0020] The subject 1 is placed between the radiation source 7 and the detector 8. The robot arm 5 serves as a movement mechanism for the radiation source 7 and the detector 8, and moves the radiation source 7 and the detector 8 in the same direction (X direction) along the detection surface 8c of the detector 8 while maintaining a fixed distance (L) (see FIG. 4). The X direction is not limited to the horizontal direction as long as the radiation source 7 and the detector 8 move straight in the same direction. The radiation source 7 emits radiation 4 to irradiate the subject 1 with the radiation 4 . The detector 8 detects the radiation 4 emitted by the radiation source 7 and transmitted through the subject 1 . FIG. 1 shows an example of a subject 1, which is a door panel of an automobile.

[0021] (Hardware configuration of depth measurement device 10) Next, an example of the hardware configuration of the depth measurement device 10 will be described with reference to FIG. FIG. 2 is a block diagram for explaining an example of the hardware configuration of the depth measurement device 10. As shown in FIG. The depth measurement device 10 includes a communication interface 10a, a read-only memory (ROM) 10b, a random access memory (RAM) 10c, a storage unit 10d, a calculation unit 10e, and an input / output interface 10f. Furthermore, the depth measurement device 10 includes an input device 10g and an output device 10h that input and output data via an input / output interface 10f. The input device 10g is an external device that inputs data to the depth measurement device 10, and includes, for example, the detector 8, the keyboard 11, and the mouse 12. The output device 10h is an external device that outputs data generated by the depth measurement device 10, and refers to the robot arm 5, which is a moving mechanism, the radiation source 7, the monitor 14, the printer 15, the speaker 16, and the like.

[0022] The radiation source 7 irradiates the subject 1 with radiation 4, and the detector 8 detects the radiation 4 that has passed through the subject 1. An example of the detector 8 may be an X-ray detector that detects X-rays, which are the radiation 4. More specifically, the detector 8 may be a photographic plate, photographic film, an imaging plate (IP), a flat panel detector (FPD), or the like. The radiation 4 detected by the detector 8 is displayed as a captured image, which is a two-dimensional distribution of the brightness of the radiation 4. The keyboard 11 is a type of computer input device, and is a device for transmitting data to the depth measurement device 10 by pressing keys for inputting characters and performing operations. The mouse 12 is a type of computer input device, and is used to point to and select the location of an object displayed on the screen of the monitor 14 of the depth measurement device 10. As described above, the robot arm 5, which is a movement mechanism, moves the radiation source 7 and the detector 8 in the same direction along the detection surface 8c of the detector 8 while maintaining the fixed distance (L) therebetween. The robot arm 5 may also move the connection member 6, which connects the radiation source 7 and the detector 8 that are facing each other while maintaining the fixed distance (L), in the direction along the detection surface 8c of the detector 8.

[0023] The radiation source 7 is a radiation generating device for irradiating the subject 1 with radiation 4, and the operation of the radiation source 7, such as the timing of irradiation of the radiation 4, is controlled by a depth measurement device 10. The monitor 14 is a device that displays and visualizes the data generated by the depth measurement device 10 on a screen. The printer 15 is a printing machine that prints the data generated by the depth measurement device 10 onto a paper medium or the like. The speaker 16 is a device that converts an electrical signal based on the data generated by the depth measurement device 10 into sound and emits it into the surrounding space.

[0024] The communication interface 10a has a function of performing two-way communication with other information processing devices via the information communication network 20. The depth measurement device 10 may transmit and receive data to and from the detector 8, the robot arm 5, and the radiation source 7 via the communication interface 10a instead of the input / output interface 10f. In this case, the communication interface 10a may perform bidirectional communication with the detector 8, the robot arm 5, and the radiation source 7, either by wired communication or wireless communication. The wireless communication method is not particularly limited, and may be Wi-Fi (registered trademark), LoRa (registered trademark), Bluetooth (registered trademark), Zigbee (registered trademark), infrared wireless communication, microwave wireless, broadcast wireless, satellite communication, or the like.

[0025] The ROM 10b can be used as a recording device, and stores a BIOS (Basic Input Output System) required for controlling the operation of each functional unit of the depth measurement device 10, various data used by the BIOS, and the like. The RAM 10c is used to configure the main memory accessed by the calculation unit 10e, and is also used to temporarily store various data acquired or generated by the depth measurement device 10 before storing it in the memory unit 10d. The storage unit 10d is realized by an HDD (Hard Disk Drive), an SSD (Solid State Drive), online storage, etc., and stores the OS, a depth measurement program (described later), other application software, various data used by these programs, etc. The storage unit 10d also stores various data acquired or generated by the depth measurement device 10.

[0026] The calculation unit 10e includes a CPU (Central Processing Unit), an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), etc., and is realized by a logic circuit (hardware) formed by an integrated circuit (IC (Integrated Circuit) chip, LSI (Large Scale Integration)), etc., or a dedicated circuit. The input / output interface 10f is an interface for transmitting and receiving data to and from the input device 10g and the output device 10h. The input / output interface 10f may use different standards depending on the data being handled, and may be compatible with multiple standards, such as HDMI (registered trademark), USB 2.0, USB 3.0, RS-232C, IEEE 1394, SCSI, and SASI.

[0027] (Imaging method for measuring depth by the depth measurement device 10) Next, with reference to FIG. 3, an imaging technique for measuring depth by the depth measurement device 10 will be described. FIG. 3 is an example flowchart of an imaging method for depth measurement by the depth measurement device 10.

[0028] First step: Pre-measure the fixed distance (L) A fixed distance (L: see FIG. 4), which is the distance between the radiation source 7 and the detection surface 8c of the detector 8, is measured in advance (FIG. 3: step S21).

[0029] Second step: Imaging the object before moving the radiation source and detector Before moving the radiation source 7 and the detector 8, the radiation source 7 irradiates the subject 1 with radiation 4, and the detector 8 detects the radiation 4 that has passed through the subject 1, thereby acquiring a first captured image 35 (see FIG. 4) described below (FIG. 3: step S22).

[0030] Third step: Control the robot arm to move it a distance (d) to capture an image of the target object. The robot arm 5 is controlled to move the radiation source 7 and the detector 8 in the same direction along the detection surface 8c of the detector 8 (X direction: see FIG. 4) by a difference (d), and after the movement, a second captured image 36 (see FIG. 4) of the object 9 (subject 1) described below is acquired (FIG. 3: step S23).

[0031] 4th step: Obtain the amount of deviation (X) from the images obtained by the two captures The first captured image 35 and the second captured image 36 obtained by two captures are superimposed, and the distance between the position of the object 9 in the first captured image 35 and the position of the object 9 in the second captured image 36 is obtained as the deviation amount (X) (Figure 3: Step S24).

[0032] 5th step: Calculate the depth (L1) from the fixed distance (L), difference (d), and deviation (X). The fixed distance (L), difference (d), deviation (X), and depth (L1) satisfy the relationship of the following equation (1) (FIG. 3: step S25). Specifically, in FIG. 4, due to the similarity relationship, d:Xd=L1:L-L1 holds, and by solving this for L1, equation (1) can be obtained. Since L, d, and X are all known values, the depth measurement device 10 can calculate the distance (depth) L1 from the radiation source 7 to the object 9 from the following equation (1).

[0033]

number

[0034] (Functional configuration of depth measurement device 10) Next, the functional configuration of the depth measurement device 10 will be described with reference to FIGS. Figure 4 is a diagram for explaining the relationship between multiple positions and multiple distances when obtaining a formula for calculating the first distance (L1) of the depth measurement device 10, Figure 5 is a diagram for explaining the measurement of the deviation amount (X) of the depth measurement device 10, and Figure 6 is a block diagram for explaining an example of the functional configuration of the depth measurement device 10.

[0035] First, with reference to FIG. 4, the relationship between a plurality of positions and a plurality of distances when obtaining a mathematical formula for calculating the first distance (L1) of the depth measurement device 10 will be described. The depth direction from the radiation source 7 toward the detector 8 refers to the Y-axis direction in FIG. 4, and the direction along the detection surface 8c of the detector 8 refers to the X-axis direction in FIG. In other words, the Y-axis direction is the direction in which radiation 4 is emitted straight from radiation source 7 towards detection surface 8c of detector 8 directly facing it, and the X-axis direction is perpendicular to this Y-axis direction. Point P0 indicates the position of the object 9, and becomes the first position and the second position depending on the relative positional relationship based on the radiation source 7 and detector 8 before and after the movement, i.e., the first position of the object 9 relative to the radiation source 7 and detector 8 (i.e., radiation source 7a, detector 8a) before the movement, and the second position of the object 9 relative to the radiation source 7 and detector 8 (i.e., radiation source 7b, detector 8b) after the movement. As will be described later, the first position of the object 9 is a first distance (L1) from the radiation source 7a in the depth direction (Y direction) from the radiation source 7a toward the detector 8a, and a second distance (L2) from the radiation source 7a in the direction along the detection surface 8c of the detector 8a (X direction). As will be described later, the second position of the object 9 is a first distance (L1) from the radiation source 7b in the depth direction (Y direction) from the radiation source 7b toward the detector 8b, and a third distance (L3) different from the second distance (L2) from the radiation source 7b in the direction along the detection surface 8c of the detector 8b (X direction).

[0036] Point P1 indicates the position of the radiation source 7a before the radiation source 7 and detector 8 are moved. Point P2 indicates the position of the radiation source 7b after the radiation source 7 and detector 8 have been moved. The radiation source 7 and the detector 8 are moved by a difference (d) by controlling the robot arm 5. In FIG. 4, the radiation source 7 and the detector 8 before the movement are referred to as the radiation source 7a and the detector 8a, and the radiation source 7 and the detector 8 after the movement are referred to as the radiation source 7b and the detector 8b. The first captured image 35 is an image captured by the detector 8a before the radiation source 7 and the detector 8 are moved, and is obtained by converting the two-dimensional distribution of the brightness of the radiation 4 into an captured image by the detector 8a after the radiation 4 emitted from the radiation source 7a passes through the subject 1 (object 9) and is detected by the detector 8a. The second captured image 36 is an image captured by the detector 8b after the radiation source 7 and the detector 8 have moved, and is obtained by converting the two-dimensional distribution of the brightness of the radiation 4 into an captured image by the detector 8b after the radiation 4 emitted from the radiation source 7b passes through the subject 1 (object 9) and is detected by the detector 8b. The reconstructed image 37 is a composite image obtained by superimposing and reconstructing the first captured image 35 and the second captured image 36. Since the radiation 4 emitted from the radiation source 7 spreads radially and uniformly, it is desirable that point P1 of the radiation source 7a be located opposite the center of the detector 8a, and point P2 of the radiation source 7b be located opposite the center of the detector 8b.

[0037] The difference (d) is the travel distance of the robot arm 5, that is, the travel distance of the radiation source 7 and the detector 8. Point P3 indicates the position of the image of object 9 that appears on detection plane 8c of detector 8a, and is recorded as point P5 in first captured image 35 and as point P7 in reconstructed image 37. Point P4 indicates the position of the image of object 9 that appears on detection plane 8c of detector 8b, and is recorded as point P6 in second captured image 36 and reconstructed image 37. An image 38 of the object 9 in the reconstructed image 37 shown in FIG. 5(a) is recorded at the position of point P7 in FIG. 4, and an image 39 of the object 9 in the reconstructed image 37 shown in FIG. 5(a) is recorded at the position of point P6 in FIG. 4. The displacement (X) refers to the distance between points P6 and P7 on the reconstructed image 37.

[0038] Next, the derivation of the above formula (1) will be described with reference to FIG. Since the first triangle with vertices P0, P1, and P2 and the second triangle with vertices P0, P3, and P4 are similar, the following formula (2) is derived. Rearranging both sides of formula (2) yields formula (3). Converting formula (3) into a formula with L1 as the solution yields formula (1) above.

[0039]

number

[0040] Next, a method for measuring the amount of deviation (X) will be described with reference to FIG. 5A and 5B are diagrams for explaining the measurement of the displacement amount (X) of the depth measurement device 10. Fig. 5A is a reconstructed image 37, and Fig. 5B is a diagram showing the relationship between the contours 38a and 39a of the images 38 and 39 of the object 9 and the amount of transmitted radiation (T), with the horizontal axis representing the direction along the detection surface 8c of the detector 8 (X axis) and the vertical axis representing the amount of transmitted radiation (T). Since the object 9 is a space existing inside the subject 1, the image 38 of the object 9 in the first captured image 35 in Figure 5(a) and the image 39 of the object 9 in the second captured image 36 have a higher luminance and appear brighter because the amount of radiation transmitted through them is greater than the surrounding area. The first captured image 35 is captured by the radiation source 7a and the detector 8a, which are the radiation source 7 and the detector 8 before movement. After the radiation source 7 and the detector 8 move by a difference (d) in the direction along the detection surface 8c (X direction), the second captured image 36 is captured by the radiation source 7b and the detector 8b.

[0041] The contours 38 a, 39 a of the object 9 are determined depending on the amount of radiation 4 transmitted through it. When the amount of transmitted radiation 4 is greater, it can be estimated that an object 9, which is space, exists, and when the amount of transmitted radiation 4 is less, it can be estimated that an object 9, which is space, does not exist. In a location where the object 9 is present, the amount of transmitted radiation is large, resulting in a high brightness and an image that appears white, as shown in Figure 5. On the other hand, in a location where the object 9 is not present, the amount of transmitted radiation is small, resulting in a low brightness and an image that appears dark, as shown in Figure 5. Therefore, points B and C on the graph line 40 showing the amount of radiation transmitted through the first captured image 35 correspond to positions on the contour 38a of the image 38 of the object 9, and points F and G on the graph line 41 showing the amount of radiation transmitted through the second captured image 36 correspond to positions on the contour 39a of the image 39 of the object 9 (see Figure 5(b)). That is, the amount of deviation (X) can be obtained by measuring the distance from point B to point F or the distance from point C to point G in the X direction in FIG. 5(b). Another method for measuring the amount of shift (X) is to gradually shift the first captured image 35 relative to the second captured image 36 on the reconstructed image 37, and obtain the amount of shift of the first captured image 35 when the brightness matching rate between the images 38 and 39 of the object 9 is highest (when the image 38 of the first captured image 35 and the image 39 of the second captured image 36 overlap) as the amount of shift (X).

[0042] Next, the functional configuration of the depth measurement device 10 will be described with reference to FIG. The depth measurement device 10 loads a depth measurement program (described later) stored in the storage unit 10d into a main memory configured with a RAM 10c, etc. The calculation unit 10e accesses the main memory into which the depth measurement program has been loaded and executes the depth measurement program. By executing the depth measurement program, the depth measurement device 10 provides the calculation unit 10e with functional units such as a first acquisition unit 30, a second acquisition unit 31, an identification unit 32, a calculation unit 33, and an output unit .

[0043] The first acquisition unit 30 acquires a first captured image 35 of an object 9 located at a first position (P0) at a first distance (L1) from the radiation source 7a in a depth direction (Y direction) from the radiation source 7a toward the detector 8a and at a second distance (L2) from the radiation source 7a in a direction along the detection surface 8c of the detector 8a (X direction) (see FIG. 4). The first acquisition unit 30 executes "imaging the object before moving the radiation source / detector (step S22)" in the flowchart of the imaging method shown in FIG.

[0044] The second acquisition unit 31 acquires a second captured image 36 of an object 9 located at a second position (P0) at a first distance (L1) from the radiation source 7b in the depth direction (Y direction) and at a third distance (L3) from the radiation source 7b in a direction along the detection surface 8c of the detector 8b that is different from the second distance (L2). The second acquisition unit 31 executes "controlling the robot arm and moving it by a difference (d) to capture an image of the object (step S23)" in the flowchart of the imaging method shown in FIG.

[0045] The specifying unit 32 specifies the amount of deviation (X) between the object 9 included in the first captured image 35 and the object 9 included in the second captured image 36. The determination unit 32 executes "obtain the amount of deviation (X) from the images obtained by two imaging operations (step S24)" in the flowchart of the imaging method shown in FIG. 3, and determines the amount of deviation (X). The specifying unit 32 measures the amount of deviation (X) as described above based on the reconstructed image 37 obtained by superimposing the first captured image 35 and the second captured image 36 (see FIG. 5).

[0046] The calculation unit 33 calculates the first distance (L1) based on the fixed distance (L), the difference (d) between the second distance (L2) and the third distance (L3), and the deviation amount (X). The calculation unit 33 executes "calculating the depth (L1) from the fixed distance (L), the difference (d), and the amount of deviation (X) (step S25)" in the flowchart of the imaging method shown in FIG. 3, and calculates the first distance (L1). The calculation unit 33 substitutes the fixed distance (L), the difference (d), and the amount of deviation (X) into the above-described formula (1) to calculate the first distance (L1), which is the depth of the object 9. That is, the calculation unit 33 divides the difference (d) by the amount of deviation (X) and multiplies the result by the fixed distance (L) to calculate the first distance (L1). The difference (d) refers to the distance that the radiation source 7 and the detector 8 move in the direction along the detection surface 8c of the detector 8 (X direction), and is the distance that the radiation source 7a moves from the position of the radiation source 7a when the first captured image 35 is captured to the position of the radiation source 7b when the second captured image 36 is captured.

[0047] The output unit 34 outputs the first distance (L1). The output unit 34 outputs the first distance (L1), which is the depth of the object 9, to a monitor 14, a printer 15, a speaker 16, and the like connected to the depth measurement device 10.

[0048] (Regarding the depth measurement device 10 according to another embodiment) In the depth measurement device 10 according to the embodiment described above, the radiation source 7 and the detector 8 are moved relative to the object 9 to acquire the first captured image 35 and the second captured image 36. In another embodiment of the depth measurement device 10, the positions of the radiation source 7 and the detector 8 are fixed, and a movement mechanism is provided that moves the object 9 between the radiation source 7 and the detector 8 in a direction along the detection surface 8c of the detector 8 (X direction), and the difference (d) is the movement distance from the position of the object 9 when the first captured image 35 is captured to the position of the object 9 when the second captured image 36 is captured. The depth measurement device 10 according to another embodiment may use a robot arm 5 as a movement mechanism, and the object 9 may be moved by the robot arm 5. In the depth measurement device 10 of other embodiments, a fixed distance (L) is acquired (step S21) according to the flowchart of the imaging method shown in Figure 3, and a shift amount (X) is acquired from the reconstructed image 37 of the first captured image 35 and the second captured image 36 (steps S22 to S24), and the depth (L1) can be calculated by substituting the fixed distance (L) and the shift amount (X) into equation (1) together with the difference (d), which is the amount of movement of the object 9 (step S25).

[0049] (Depth measurement method and depth measurement program) Next, a depth measurement program according to one embodiment of the present invention will be described together with a depth measurement method with reference to Fig. 7. Fig. 7 is a flowchart of the depth measurement program according to this embodiment. The depth measurement method is executed by the calculation unit 10e of the depth measurement device 10 based on the depth measurement program. The depth measurement program includes a first acquisition step S30, a second acquisition step S31, a determination step S32, and a calculation step S33. The depth measurement program causes the calculation unit 10e of the depth measurement device 10 to perform a first acquisition function, a second acquisition function, a determination function, a calculation function, etc. These functions are executed in the order shown in the flowchart of Figure 7, but the order can also be changed as appropriate. Note that each function overlaps with the description of the various functional units of the depth measurement device 10 described above, and therefore detailed description thereof will be omitted.

[0050] The first acquisition function acquires a first captured image 35 of an object 9 located at a first position (P0) at a first distance (L1) from the radiation source 7 in the depth direction (Y direction) from the radiation source 7 toward the detector 8, and at a second distance (L2) from the radiation source 7 in the direction along the detection surface 8c of the detector 8 (X direction) (S30: first acquisition step).

[0051] The second acquisition function acquires a second captured image 36 of an object 9 located at a second position (P0) at a first distance (L1) from the radiation source 7 in the depth direction (Y direction) and at a third distance (L3) different from the second distance (L2) from the radiation source 7 in the direction along the detection surface 8c of the detector 8 (X direction) (S31: second acquisition step).

[0052] The identifying function identifies the amount of deviation (X) between the object 9 included in the first captured image 35 and the object 9 included in the second captured image 36 (S32: identifying step).

[0053] The calculation function calculates the first distance (L1) based on the fixed distance (L), the difference (d) between the second distance (L2) and the third distance (L3), and the deviation amount (X) (S33: calculation step).

[0054] (Other embodiments of the depth measurement method and depth measurement program) Next, a depth measurement program according to another embodiment of the present invention will be described together with a depth measurement method according to another embodiment with reference to Fig. 8. Fig. 8 is an example of a flowchart of the depth measurement program according to another embodiment. The flowchart of the depth measurement program according to another embodiment shown in FIG. 8 differs from the flowchart of the depth measurement program shown in FIG. 7 in that an output step S34 is added. The assistance method according to the other embodiment is executed by the calculation unit 10e of the depth measurement device 10 based on the depth measurement program according to the other embodiment shown in FIG. The depth measurement program according to another embodiment shown in FIG. 8 includes a first acquisition step S30, a second acquisition step S31, a determination step S32, a calculation step S33, and an output step S34.

[0055] The depth measurement program according to another embodiment shown in Fig. 8 causes the calculation unit 10e of the depth measurement device 10 to realize a first acquisition function, a second acquisition function, a specification function, a calculation function, an output function, etc. These functions are executed in the order shown in the flowchart of Fig. 8, but the order can also be changed as appropriate. Hereinafter, the depth measurement method and depth measurement program according to another embodiment shown in FIG. 8 will be described, focusing only on the differences from the depth measurement method and depth measurement program shown in FIG. Furthermore, since each function overlaps with the description of the various functional parts of the depth measurement device 10 described above, detailed description thereof will be omitted. The output function outputs the first distance (L1) (S34: output step).

[0056] According to the depth measurement device 10 of the above-described embodiment, the detector 8 is fixed relative to the radiation source 7, and therefore, a decrease in depth measurement accuracy due to relative movement between the radiation source 7 and the detector 8 can be suppressed.

[0057] Furthermore, according to the depth measurement device 10 of the above-described embodiment, the radiation source 7 and the detector 8 are attached to one robot arm 5 via a connecting member 6, which requires less space than when two robot arms are used, and the teaching work can be performed on only one robot arm, thereby reducing complexity.

[0058] Furthermore, according to the depth measurement device 10 of the above-described embodiment, since the detector 8 is fixed relative to the radiation source 7, an actuator for moving only the radiation source 7 is not required, which prevents the device configuration from becoming larger and more complex.

[0059] Furthermore, according to the depth measurement device 10 of the above-described embodiment, the amount of displacement (X) can be obtained by imaging the subject 1 twice, before and after the movement of the radiation source 7 and the detector 8, thereby enabling efficient use of radiation and suppressing the disadvantages, such as the dangers and hassles, associated with continuous irradiation of radiation.

[0060] Furthermore, according to the depth measurement device 10 of the above-described embodiment, a reconstructed image 37 can be obtained based on two captured images (the first captured image 35 and the second captured image 36) obtained by capturing images of the subject 1 twice, before and after the movement of the radiation source 7 and the detector 8, which is easier than obtaining a reconstructed image 37 based on three or more captured images obtained by capturing images continuously, such as a video.

[0061] Furthermore, according to the depth measurement device 10 of the above-described embodiment, the first captured image 35 and the second captured image 36 are captured while the radiation source 7 and the detector 8 are stationary, and therefore, are acquired as clearer images, making it possible to measure the amount of deviation (X) with high accuracy.

[0062] Furthermore, according to the depth measurement device 10 of the above-described embodiment, the position of the contours 38a, 39a of the image of the object 9 when measuring the amount of deviation (X) can be easily determined because it can be estimated that the object (space) 9 is located at a position on the X-axis showing a larger value of the amount of radiation transmitted in the graph showing the distribution of the amount of radiation transmitted in the reconstructed image 37.

[0063] The present invention is not limited to the depth measurement device 10, depth measurement method, and depth measurement program according to the above-described embodiments, and can be implemented by various other modified examples or application examples without departing from the gist of the present invention as set forth in the claims. Also, although the term "data" is used in the above-described embodiments, the term "data" can be replaced with "information," and the term "information" can be replaced with "data." [Explanation of symbols]

[0064] 1. Subject 2 pedestal 3 Fixture 4. Radiation 5. Robotic Arm 6 Connecting members 7 Radiation source 7a Radiation source before moving 7b Radiation source after transfer 8 Detectors 8a Detector before movement 8b Detector after movement 8c Detection surface 9 Objects 10 Depth measuring device 10a Communication Interface 10b ROM 10c RAM 10d storage section 10e Calculation unit 10f Input / Output Interface 10g input device 10h output device 11 Keyboard 12 Mouse 14 monitors 15 Printers 16 speakers 20 Information and Communications Networks 30 First acquisition part 31 Second acquisition part 32 Specific part 33 Calculation section 34 Output section 35 First captured image (image captured before movement) 36 Second captured image (image captured after movement) 37 Reconstructed images 38 Image of object in first captured image 38a Contour 39 Image of the object in the second captured image 39a Contour 40 Graph Lines 41 Graph Lines L fixed distance L1 1st distance L2 2nd distance L3 Third distance P0 point (1st position, 2nd position) P1 point P2 point P3 point P4 points P5 points P6 points

Claims

1. a radiation source that emits radiation; a detector that faces the radiation source at a fixed distance and detects radiation emitted from the radiation source; a first acquisition unit that acquires a first captured image of an object present at a first position where a distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and a distance from the radiation source in a direction along a detection surface of the detector is a second distance; a second acquisition unit that acquires a second captured image of the object present at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; and an identifying unit that identifies a deviation amount between the object included in the first captured image and the object included in the second captured image; a calculation unit that calculates the first distance based on the fixed distance, a difference between the second distance and the third distance, and the deviation amount; A depth measurement device comprising:

2. a moving mechanism that moves the radiation source and the detector in the same direction along a detection surface of the detector while maintaining the fixed distance, The difference is a moving distance from the position of the radiation source when the first captured image is captured to the position of the radiation source when the second captured image is captured.

2. The depth measurement device according to claim 1 .

3. The moving mechanism is a robot arm that moves a connection member connecting the radiation source and the detector, which are facing each other while maintaining the fixed distance, in a direction along a detection surface of the detector.

3. The depth measuring device according to claim 2.

4. a moving mechanism that fixes positions of the radiation source and the detector and moves the object between the radiation source and the detector in a direction along a detection surface of the detector, The difference is a moving distance from the position of the object when the first captured image is captured to the position of the object when the second captured image is captured.

2. The depth measurement device according to claim 1 .

5. The calculation unit calculates the first distance by dividing the difference by the amount of deviation and multiplying the result by the fixed distance. The depth measurement device according to any one of claims 1 to 4.

6. an output unit that outputs the first distance 6. The depth measuring device according to claim 5, wherein:

7. a computer capable of communicating with a radiation source that emits radiation and a detector that faces the radiation source at a fixed distance and detects the radiation emitted by the radiation source, a first acquisition step of acquiring a first captured image of an object present at a first position where a distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and a distance from the radiation source in a direction along a detection surface of the detector is a second distance; a second acquisition step of acquiring a second captured image of the object present at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; a specifying step of specifying a deviation amount between the object included in the first captured image and the object included in the second captured image; a calculation step of calculating the first distance based on the fixed distance, a difference between the second distance and the third distance, and the deviation amount; A depth measurement method comprising:

8. a computer capable of communicating with a radiation source that emits radiation and a detector that faces the radiation source at a fixed distance and detects the radiation emitted by the radiation source; a first acquisition function that acquires a first captured image of an object present at a first position where a distance from the radiation source in a depth direction from the radiation source to the detector is a first distance and a distance from the radiation source in a direction along a detection surface of the detector is a second distance; and a second acquisition function that acquires a second captured image of the object that is present at a second position where the distance from the radiation source in the depth direction is the first distance and the distance from the radiation source in a direction along the detection surface of the detector is a third distance different from the second distance; and a specifying function for specifying a deviation amount between the object included in the first captured image and the object included in the second captured image; a calculation function for calculating the first distance based on the fixed distance, a difference between the second distance and the third distance, and the deviation amount; A depth measurement program characterized by realizing the above.

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