Radiation source direction detection device, radiation source direction detection method, attitude estimation device, attitude estimation method, imaging device, mobile object, analysis device, and information processing device

Abstract

A radiation source direction detection device according to the present invention includes: a radiation detection unit in which a plurality of pixels for detecting radiation are discretely arranged three-dimensionally; and a computation unit that performs computation for identifying the direction of a radiation source on the basis of the result of the radiation detection by the plurality of pixels in the radiation detection unit.

Description

Radiation source direction detection device, radiation source direction detection method, attitude estimation device, attitude estimation method, imaging device, moving object, analysis device, information processing device

[0001] The present technology relates to a radiation source direction detection device, a radiation source direction detection method, a posture estimation device, a posture estimation method, an imaging device, a moving body, an analysis device, and an information processing device, and in particular to a technology for detecting the direction of a radiation source.

[0002] For example, devices are known that detect radiation (ionizing radiation) such as alpha rays, beta rays, and solar neutrinos.

[0003] As a related prior art, the following Patent Document 1 can be cited: Patent Document 1 discloses a technique for detecting the direction of the sun as seen from an artificial satellite based on imaging data.

[0004] JP 2015-074382 A

[0005] Here, conventional radiation detection devices can detect radiation, but cannot accurately detect the direction from which the radiation arrives.

[0006] The present technology has been made in view of the above circumstances, and aims to realize a radiation detection device that can detect the direction in which a radiation source is located based on the radiation detection result.

[0007] The radiation source direction detecting device according to the present technology includes a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit. By discretely arranging the plurality of pixels that detect radiation in three dimensions as described above, it is possible for radiation that arrives from a certain direction to pass through a certain pixel and then pass through another pixel. Therefore, for example, if a certain pixel detects radiation and then another pixel detects radiation, it is possible to estimate that the radiation arrived from a direction that passed through these two pixels. In other words, it is possible to identify the direction of the radiation source based on the radiation detection results of the plurality of pixels.

[0008] Furthermore, a posture estimation device according to the present technology includes a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels for detecting radiation are discretely arranged in three dimensions, a calculation unit that performs calculations to determine the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit, a posture estimation unit that estimates at least its own posture based on detection information from an IMU, and a correction unit that corrects errors occurring in the detection information from the IMU based on information about the direction of the radiation source detected by the radiation source direction detection unit. If the radiation source detected by the radiation source direction detection unit is a radiation source whose position is known, such as the sun, it is possible to determine an absolute direction with respect to the direction in which the device is facing based on the radiation source direction detected by the radiation source direction detection unit. Therefore, by using the information about the radiation source direction detected by the radiation source direction detection unit, it is possible to correct errors occurring in the detection information from the IMU, such as detection errors in acceleration, angular velocity, and orientation.

[0009] An imaging device according to the present technology includes: an imaging unit that captures an image of a subject to obtain a captured image; a radiation detection unit having a plurality of pixels that detect radiation discretely arranged in three dimensions; a radiation source direction detection unit that performs a calculation to identify the direction of the radiation source based on a detection result of the radiation by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information of an IMU; a correction unit that corrects an error occurring in the detection information of the IMU based on information about the direction of the radiation source detected by the radiation source direction detection unit; and a blur correction unit that performs blur correction processing on the captured image based on information about the posture estimated by the posture estimation unit based on the detection information of the IMU corrected by the correction unit. This realizes an imaging device that can perform blur correction processing based on detection information of an IMU in which errors have been appropriately corrected.

[0010] Furthermore, a mobile body according to the present technology includes a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results from the plurality of pixels in the radiation detection unit, an attitude estimation unit that estimates at least its own attitude based on detection information from an IMU, a correction unit that corrects errors that occur in the detection information from the IMU based on information about the direction of the radiation source detected by the radiation source direction detection unit, and an attitude control unit that performs attitude control processing based on the attitude information estimated by the attitude estimation unit based on the detection information from the IMU after correction by the correction unit. This makes it possible to realize a mobile body that can perform attitude control with high accuracy.

[0011] An analysis device according to the present technology includes a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results from the plurality of pixels in the radiation detection unit, a posture estimation unit that estimates at least its own posture based on detection information from an IMU, a correction unit that corrects errors that occur in the detection information from the IMU based on information about the direction of the radiation source detected by the radiation source direction detection unit, and a motion analysis unit that performs motion analysis processing on its own posture based on information about the posture estimated by the posture estimation unit based on the detection information from the IMU after correction by the correction unit. This makes it possible to realize an analysis device that can perform highly accurate motion analysis.

[0012] Furthermore, an information processing device according to the present technology includes a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit, the information processing device including: a receiving unit that receives information on the direction of the radiation source identified from the detection results of the radiation source direction detection unit from a plurality of terminal devices that are located at different positions on the Earth, and a radiation source position calculation unit that performs calculations to identify the position of the radiation source based on the information on the direction of the radiation source received by the receiving unit from the plurality of terminal devices and position information of the plurality of terminal devices. This makes it possible to realize an information processing device that is capable of determining the position of a target radiation source with high accuracy.

[0013] 1 is a diagram for explaining an example configuration of a radiation source direction detector (radiation detection unit) included in a radiation source direction detecting device according to an embodiment of the present technology; FIG. 2 is a diagram showing an example configuration of a pixel in the radiation source direction detector; FIG. 3 is a diagram showing another example configuration of a pixel in the radiation source direction detector; FIG. 4 is a diagram showing an example of an enlarged image of a film formed by a powder method; FIG. 5 is a diagram showing an example of an enlarged image of a film formed by a vapor deposition method; FIG. 6 is a diagram showing an example of an enlarged image of a film formed by a sputtering method; FIG. 7 is an explanatory diagram of an example configuration of a radiation detection unit configured with a plurality of pixels; FIG. 8 is a diagram showing an example of mounting a radiation detection unit on a flexible substrate; FIG. 9 is an explanatory diagram of the characteristics of solar neutrinos; FIG. 10 is an explanatory diagram of a method for detecting only neutrinos that pass through the center of the radiation source direction detector; FIG. 11 is an explanatory diagram of a time window method in an embodiment; FIG. 12 is an explanatory diagram of a window period in an embodiment; 27 is a block diagram showing an example of the configuration of a radiation source direction detecting unit (radiation source direction detecting device) according to an embodiment. FIG. 28 is a flowchart of a process for identifying a trigger pixel. FIG. 29 is a flowchart of a process for detecting a radiation source direction based on radiation detection results in an opposing pixel area of ​​a trigger pixel. FIG. 29 is an explanatory diagram of angular resolution derived from the size of a radiation source direction detector and pixel size. FIG. 29 is a tabular diagram showing angular resolution for each combination of pixel size and size of a radiation source direction detector. FIG. 29 is a tabular diagram showing the relationship between scintillator material and reaction rate. FIG. 29 is an explanatory diagram of the rise and decay of a response to radiation. FIG. 29 is an explanatory diagram of an example structure in which a radiation / light conversion unit is arranged more inward than a photoelectric conversion element. FIG. 29 is an explanatory diagram of an example wiring for the example of FIG. 25. FIG. 29 is an external view showing an example of a soccer ball-shaped radiation source direction detector. FIG. 29 is a diagram showing an example of a flexible substrate used in the example of FIG. 27. FIG. 29 is an external view showing an example of a cubic-shaped radiation source direction detector. FIG. 30 is an explanatory diagram of an example in which a target radiation source is present on an extension line between vertices.31 is a diagram illustrating the distribution of detection intensity within an opposing pixel area in the case of FIG. 30. FIG. 32 is a block diagram illustrating the configuration of a radiation source direction detection unit as another configuration example of an embodiment. FIG. 33 is an explanatory diagram of a scintillator with different attenuation characteristics depending on the type of radiation. FIG. 34 is a conceptual diagram of a radiation source direction detected as direction information in a local coordinate system. FIG. 35 is a diagram for explaining the direction differences between the gravity direction and the reference orientation direction with respect to a reference radiation source direction in a world coordinate system. FIG. 36 is an explanatory diagram illustrating calculation of the gravity direction and the reference orientation direction in a local coordinate system based on the detected radiation source direction and the direction difference. FIG. 37 is a block diagram illustrating an example of the configuration of a posture estimation device as a first example of an embodiment. FIG. 38 is an explanatory diagram of a delay time to be compensated for in a posture estimation device as a second example of an embodiment. FIG. 39 is a block diagram illustrating an example of the configuration of a posture estimation device as a second example of an embodiment. FIG. 39 is a block diagram illustrating an example of the configuration of a posture estimation device as a third example of an embodiment. FIG. 39 is a diagram illustrating a schematic configuration example of a smartphone (analysis device) to which a posture estimation device as an embodiment is applied. FIG. 39 is a diagram illustrating a schematic configuration example of an imaging device to which a posture estimation device as an embodiment is applied. FIG. 39 is a diagram illustrating a schematic configuration example of a moving body to which a posture estimation device as an embodiment is applied. FIG. 39 is an explanatory diagram of a grid array of a device to which a posture estimation device is applied. The grid array system according to the present invention is a system for observing supernova explosions using a grid array.

[0014] Hereinafter, with reference to the accompanying drawings, embodiments according to the present technology will be described in the following order: <1. Regarding the radiation source direction detection device> [1-1. Configuration of the radiation source direction detector (radiation detection section)] [1-2. Radiation source direction detection method and configuration of the radiation source direction detection unit] [1-3. Regarding the size of the radiation source direction detector] [1-4. Regarding the reaction rate of the scintillator] [1-5. Radiation source direction detector as another example] [1-6. Other, alternative configuration examples] <2. Regarding the attitude estimation device> [2-1. Attitude estimation device as a first example] [2-2. Attitude estimation device as a second example] [2-3. Attitude estimation device as a third example] <3. Application examples of the attitude estimation device> <4. Grid array system> <5. Modified examples> <6. Summary of embodiments> <7. The present technology>

[0015] 1. Regarding the radiation source direction detecting device 1-1. Configuration of the radiation source direction detector (radiation detection unit) Fig. 1 is a diagram for explaining an example configuration of a radiation source direction detector 10 included in a radiation source direction detecting device according to an embodiment of the present technology. The radiation source direction detector 10 is an example of a "radiation detection unit" according to the present technology. Here, in this specification, "radiation" means ionizing radiation.

[0016] The radiation source direction detector 10 has a spherical portion 10a having a substantially spherical shape. The figure shows a cross section of the spherical portion 10a. A plurality of pixels Px are formed on the entire surface (spherical surface) of the spherical portion 10a. As shown enlarged in the figure, each pixel Px has a radiation / light conversion portion 2 and a photoelectric conversion element 3.

[0017] The radiation / light conversion unit 2 converts radiation into light by emitting light in response to radiation. A scintillator may be used as the radiation / light conversion unit 2. Alternatively, a unit that performs radiation / light conversion by the Cherenkov effect may be used as the radiation / light conversion unit 2. In this example, a scintillator is used as the radiation / light conversion unit 2.

[0018] In this example, the radiation source for which direction detection is to be performed is assumed to be the sun. In this case, the radiation to be detected is solar neutrinos. In this case, the scintillator material used for the radiation-to-light conversion unit 2 is one that is sensitive to solar neutrinos. Both inorganic and organic scintillator materials are available. Inorganic scintillators are advantageous in terms of light output efficiency and linearity, but tend to have a long response time. Organic scintillators tend to have a fast response but a low light output. Examples of scintillator materials include heavy element single crystal materials. Other possible materials include rare earths and transition metals. Specific examples of scintillator materials include CsBr, CdS:In, NE111, Naton136, NE102A, LaBr3:Ce, HfO2, CsGd2F7:Ce, and NaI(TI).

[0019] In this example, a SPAD (Single Photon Avalanche Diode) element is used as the photoelectric conversion element 3 of each pixel Px. Although not shown, when a SPAD element is used as the photoelectric conversion element 3, each pixel Px is provided with a counting circuit that counts photons based on the electrical signal obtained by photoelectric conversion of the SPAD element. In this case, the number of photons counted by the counting circuit in the pixel Px indicates the amount of light received and emitted by the radiation-to-light conversion unit 2. Because the amount of light emitted by the radiation-to-light conversion unit 2 tends to increase in accordance with the amount of incident radiation, the number of photons counted in this case correlates with the amount of radiation detected.

[0020] The use of a SPAD element as the photoelectric conversion element 3 is merely an example, and other photoelectric conversion elements may also be used.

[0021] As shown in Figure 1, the source direction detector 10 of this example employs a structure in which the radiation / light conversion unit 2 is arranged outside the photoelectric conversion element 3 in each pixel Px. Radiation has high transparency, and neutrinos in particular have the property of passing through most materials. For this reason, the source direction detector 10 can detect not only radiation incident from outside, but also radiation that has passed through the inside of the source direction detector 10.

[0022] An example of the structure of a pixel Px will be described with reference to Figures 2 and 3. Figure 2 shows an example of a structure in which a radiation / light conversion unit 2 serving as a scintillator is formed by vapor deposition on a semiconductor substrate 4 on which a photoelectric conversion element 3 is formed. The photoelectric conversion element 3 is formed on the semiconductor substrate 4 in units of pixels Px. In this example, after forming the radiation / light conversion unit 2 by vapor deposition of a scintillator material on the semiconductor substrate 4, a stacked film made of an organic protective film 6, a reflective film 5, and another organic protective film 6 is formed on the outside of the radiation / light conversion unit 2 in units of pixels Px, as shown in the figure. By forming the reflective film 5, light generated in the radiation / light conversion unit 2 can be efficiently guided to the photoelectric conversion element 3.

[0023] When the radiation / light conversion unit 2 is formed on the semiconductor substrate 4 by vapor deposition as shown in FIG. 2, the degree of adhesion between the radiation / light conversion unit 2 and the photoelectric conversion element 3 can be increased, which has the advantage of increasing the light-receiving efficiency of the photoelectric conversion element 3 with respect to light generated by the radiation / light conversion unit 2.

[0024] 3 shows an example of a structure in which a radiation / light conversion unit 2 serving as a scintillator is formed on a reflector by vapor deposition. In this case, the reflector is made of, for example, an aluminum thin film that functions as a reflective film 5. The size of the reflector is equivalent to the size of a plurality of pixels Px. A scintillator material is vapor deposited on the reflective film 5 serving as a reflector to form the radiation / light conversion unit 2, and an organic protective film 6 is formed on the outside of the radiation / light conversion unit 2 for each pixel Px. This structure in which the radiation / light conversion unit 2 and the organic protective film 6 are formed on the reflective film 5 for each pixel Px is then bonded to a semiconductor substrate 4 on which photoelectric conversion elements 3 are formed for each pixel Px.

[0025] In the structural example of FIG. 3 , the degree of contact between the radiation / light conversion unit 2 and the photoelectric conversion element 3 tends to be lower than in the case of FIG. 2 , which may result in light leakage and a tendency for the efficiency of the photoelectric conversion element 3 to receive light generated in the radiation / light conversion unit 2 to decrease. However, this is advantageous in terms of manufacturing costs because the manufacturing process can be simplified.

[0026] Here, in addition to the vapor deposition method described above, other methods for forming scintillators include the powder method and the sputtering method. The powder method is a method in which powder is applied. Figure 4 shows an example of an enlarged image of a film formed using the powder method. The powder method has the advantage of being able to form scintillators relatively inexpensively. On the other hand, because it is a powder, there is a trade-off: if high luminous efficiency is desired, the film thickness becomes thick, resulting in poor resolution, and if high resolution is desired, the film thickness becomes thin, resulting in poor luminous efficiency.

[0027] Compared to the powder method, the vapor deposition method and sputtering method require more expensive materials and manufacturing costs, but are stable in terms of overall performance in terms of radiation sensitivity and resolution. Figure 5 shows an enlarged image of a film formed by the vapor deposition method, and Figure 6 shows an enlarged image of a film formed by the sputtering method. Another feature of the vapor deposition method and sputtering method is that they can create columnar crystals or epitaxially grown crystals. If columnar crystals or epitaxially grown crystals can be created, emitted light can be efficiently guided to the photoelectric conversion element 3 along the extension direction of the crystal, thereby improving radiation detection accuracy.

[0028] An example of a manufacturing method for the radiation source direction detector 10 will be described with reference to Figures 7 and 8. Figure 7 is an explanatory diagram of an example of the structure of a radiation detection unit 9 configured to have a plurality of pixels Px that detect radiation. As previously described with reference to Figures 2 and 3, in this example, a photoelectric conversion element 3 is formed on the semiconductor substrate 4 for each pixel Px. In other words, a plurality of photoelectric conversion elements 3 for each pixel Px are formed on the semiconductor substrate 4. In the figure, a radiation / light conversion layer 7 represents a layer in which a radiation / light conversion unit 2 for each pixel Px is formed. As will be understood from the previous description of Figures 2 and 3, in this example, the radiation / light conversion layer 7 is formed on the semiconductor substrate 4 by a technique such as vapor deposition.

[0029] In the radiation detection unit 9, another semiconductor substrate 8 on which electronic circuits such as the count circuit that counts photons, the gain circuit that adjusts the sensitivity (gain) for each pixel Px, various logic circuits, and a communication I / F unit are formed is physically and electrically bonded to the lower layer of the semiconductor substrate 4. The semiconductor substrate 4 and the another semiconductor substrate 8 are bonded, for example, by Cu-Cu bonding.

[0030] In manufacturing the radiation source direction detector 10, a plurality of radiation detection units 9 as shown in FIG. 7 are prepared in advance. Then, the plurality of radiation detection units 9 are mounted on a flexible substrate Bs as shown in FIG. 8. Using a flexible substrate Bs as the substrate on which the radiation detection units 9 are mounted makes it easy to form the radiation source direction detector 10 into a substantially spherical shape as shown in FIG. 1. Mounting each radiation detection unit 9 on the flexible substrate Bs can be performed using a BGA (Ball Grid Array) method using a plurality of conductor balls Ba. In this case, copper can be used as the material for the conductor balls Ba in consideration of heat dissipation. An IC (Integrated Circuit) serving as a front end FE is mounted for each radiation detection unit 9 on the surface of the flexible substrate Bs opposite to the surface on which the radiation detection units 9 are mounted. The front end FE is an IC that performs I / F processing and the like to enable the radiation detection units 9 to communicate with the outside of the radiation source direction detector 10.

[0031] Although not shown in the figures, one method for forming the radiation source direction detector 10 into a substantially spherical shape is to form a flexible substrate Bs in the shape of a two-dimensionally developed sphere, and then mount a plurality of radiation detection units 9 and front end portions FE on the flexible substrate Bs. Then, the flexible substrate Bs on which the radiation detection units 9 and front end portions FE are mounted is bent and joined to form the radiation source direction detector 10 into a substantially spherical shape.

[0032] Here, the method for realizing the radiation source direction detector 10 having a three-dimensional shape such as an approximately spherical shape is not limited to the method using the flexible substrate Bs as described above. For example, a method can be adopted in which a substantially spherical substrate made of, for example, resin is prepared, and the pixel circuits including the photoelectric conversion elements 3 and the front end unit FE are mounted on the substrate by a transfer mounting technique such as MID (Molded Interconnect Device). In this case, the radiation / light conversion unit 2 may be deposited last, or may be deposited in advance on the pixel circuits including the photoelectric conversion elements 3.

[0033] [1-2. Radiation source direction detection method and configuration of radiation source direction detection unit] Next, an example of a radiation source direction detection method using the radiation source direction detector 10 and an example configuration of the radiation source direction detection unit 1 that has the radiation source direction detector 10 and detects the radiation source direction will be described.

[0034] Figure 9 is an explanatory diagram of the characteristics of solar neutrinos, specifically showing the results of a comparison of their characteristics with other radiation that could become noise components. Specifically, Figure 9A shows a comparison of the number of neutrinos, while Figure 9B shows a comparison of the number x energy. Examples of radiation that could become noise components include supernova neutrinos emitted in supernova explosions and radiation (neutrinos) from nuclear reactors. The numbers here refer to the number per square centimeter per second, and are merely the number detected by existing radiation detection devices.

[0035] Figure 9A shows that the number of incoming solar neutrinos is extraordinarily large compared to other neutrinos that can become noise components. Specifically, the number of incoming solar neutrinos (per square centimeter per second) is approximately 66 billion, the number of incoming nuclear reactor neutrinos is approximately 5.5 million, and the number of incoming supernova neutrinos is almost zero (once in several hundred years). Also, although not shown in the figure, the number of incoming geoneutrinos emitted from the Earth's interior is approximately 6 million. Although the observed energy of solar neutrinos is smaller than that of nuclear reactor neutrinos and geoneutrinos, because the number of incoming solar neutrinos is so large, the product of number and energy remains extraordinarily large, as shown in Figure 9B.

[0036] At night, solar neutrinos are observed only after passing through the Earth, and as a result, their energy decays due to the damping of neutrino oscillation. Figure 9B also shows a graph of the number of solar neutrinos x energy at night, and as shown, even at night, their large number keeps them dominant over other radiation.

[0037] As described above, solar neutrinos have the characteristic of being extremely high in radiation dose and of being uniformly incident in parallel. Therefore, in this embodiment, as shown in Fig. 10, a method is adopted in which only neutrinos passing through the center of the radiation source direction detector 10 are detected as radiation from the radiation source of interest. Due to the characteristics described above, solar neutrinos have a very high probability of passing through the center of the radiation source direction detector 10, whereas neutrinos that could become other noise components tend to arrive from random directions and therefore have a very low probability of passing through the center of the radiation source direction detector 10, as indicated by the dotted arrow in the figure. Therefore, by adopting the method described above in which only neutrinos passing through the center of the radiation source direction detector 10 are detected as radiation from the radiation source of interest, it is possible to prevent radiation that could become other noise components from being erroneously detected as radiation from the radiation source of interest.

[0038] A specific radiation source direction detection method will be described with reference to FIGS. 11 to 17 . FIG. 11 is an explanatory diagram of the time window method. In this embodiment, the time window method is adopted for detecting the radiation source direction. When a certain pixel Px detects radiation in the radiation source direction detector 10, this pixel is designated as a trigger pixel (see pixel PxT in the figure). Assuming that radiation that passes through this trigger pixel PxT passes through the center of the radiation source direction detector 10, the radiation will be detected by a pixel Px (hereinafter referred to as "opposing pixel PxO") located opposite the trigger pixel PxT. Note that the opposing pixel PxO can be expressed as the pixel Px that faces the trigger pixel PxT across the center of the radiation source direction detector 10.

[0039] Here, the time Δt it takes for radiation to pass from the trigger pixel PxT to the counter pixel PxO can be expressed as "Δt = R / C," where R is the size (diameter in this example) of the radiation source direction detector 10, where C represents the speed of light.

[0040] Since this passing time Δt is a known value once the size R is determined, a window period is defined as a period during which radiation that has passed through the trigger pixel PxT is expected to pass through the counter pixel PxO based on this passing time Δt, as shown in Fig. 12. If radiation is detected at the counter pixel PxO within this window period, it can be assumed that the radiation detected at the trigger pixel PxT passed through the center of the source direction detector 10 and was detected at the counter pixel PxO. In other words, it can be assumed that a neutrino from the sun passed from the trigger pixel PxT through the center of the source direction detector 10 and then passed through the counter pixel PxO.

[0041] In this way, if radiation is detected at a certain trigger pixel PxT and the opposing pixel PxO detects radiation within a specified window period, the direction passing from the opposing pixel PxO through the trigger pixel PxT can be identified as the direction of the sun as the target radiation source.

[0042] Here, by adopting the time window method as described above, it is possible to detect the direction of the radiation source with high accuracy by reducing the influence of radiation as a noise component other than the radiation from the target radiation source. However, because the radiation source is not a single point but has a finite size, strictly speaking, an angle error due to this size may occur.

[0043] For example, when the target radiation source is the sun as in this example, an angle error ΔD occurs as shown in Fig. 13. This angle error ΔD is calculated as follows, since the distance from the earth to the sun is 149,600,000 km and the radius of the sun is 695,508 km: ΔD=tan －１ It can be estimated as follows: (695,508 km / 149,600,000 km) = 0.266 degrees. Because this angle error ΔD occurs symmetrically, the total angle error can be expressed as ±0.266 degrees = 0.532 degrees.

[0044] In order to suppress the detection error in the radiation source direction resulting from this total angle error, this embodiment employs a method in which, rather than detecting radiation using only one pixel Px as the opposing pixel PxO, radiation is detected within a window period in an opposing pixel area Ap that includes the opposing pixel PxO and the pixels surrounding the opposing pixel PxO.

[0045] Fig. 14 shows an image of radiation from the sun incident on the opposing pixel area Ap. When the sun is viewed two-dimensionally, it can be said that the radiation dose from the sun is greatest from the center and least from the periphery. Therefore, when radiation from the sun is detected at multiple pixels Px that make up the opposing pixel area Ap, an intensity distribution according to a Gaussian distribution such as the one shown in Fig. 15 is observed. Specifically, this is an intensity distribution that has a peak at a certain pixel position within the opposing pixel area Ap, and the detected radiation dose decreases as the distance from that certain pixel position increases.

[0046] Therefore, among the radiation detected within the opposing pixel area Ap during the window period, the pixel Px with the greatest detected radiation dose can be estimated to be the pixel Px that detected radiation from the center of the sun. Therefore, by detecting the direction from this pixel Px through the trigger pixel PxT as the radiation source direction, it is possible to prevent detection errors in the radiation source direction due to the radiation source having a finite size.

[0047] A specific method for detecting the radiation source direction based on the dose distribution in the opposing pixel area Ap as described above will be described with reference to Figs. 16 and 17. Fig. 16 shows the relationship between the trigger pixel PxT, opposing pixel PxO, opposing pixel area Ap, and window period in the radiation source direction detector 10. In this case, the opposing pixel area Ap is defined as an area that is centered on the opposing pixel PxO and includes at least pixels Px within a range of ±0.266 degrees from the center of the radiation source direction detector 10, for example.

[0048] In this example, in response to the occurrence of a trigger pixel PxT, radiation detection results are obtained for each pixel Px in the opposing pixel area Ap of that trigger pixel PxT during the subsequent window period. In this example, each pixel Px repeatedly performs the above-mentioned photon count for each predetermined unit period that is shorter than the window period, and therefore the radiation detection results of each pixel Px during the window period are obtained as information on the number of photons counted for each unit period.

[0049] 17 shows an example of radiation detection results for each pixel Px in the opposing pixel area Ap obtained in a period near the window period. Specifically, the radiation detection results obtained in a period near the window period are exemplified by the radiation detection result for the opposing pixel PxO in the opposing pixel area Ap (middle row in the figure) and the radiation detection results for each pixel Px at both outer edges of the opposing pixel area Ap (top and bottom rows in the figure). In this case, radiation detection by the pixel Px is obtained as the number of photons counted per unit period as described above, and therefore the radiation detection results can be represented by a histogram with the horizontal axis representing time and the vertical axis representing the number of counts, as shown in the figure.

[0050] When the histogram described above is obtained for each pixel Px in the opposing pixel area Ap during the window period, the pixel Px with the highest peak value in the histogram can be estimated to be the pixel Px that detected radiation from the center of the target radiation source. In other words, by detecting the direction passing through the trigger pixel PxT from the pixel Px with the highest peak value in the histogram as the radiation source direction, it is possible to prevent detection errors in the radiation source direction due to the radiation source having a finite size.

[0051] 18 is a block diagram showing an example of the configuration of a radiation source direction detection unit 1 that includes a radiation source direction detector 10 and detects the radiation source direction. As shown in the figure, the radiation source direction detection unit 1 includes a radiation source direction calculation unit 11 in addition to the radiation source direction detector 10. The radiation source direction calculation unit 11 is capable of acquiring radiation detection results from each pixel Px of the radiation source direction detector 10. The radiation source direction calculation unit 11 performs calculations to identify the direction of the radiation source based on the radiation detection results from the multiple pixels Px in the radiation source direction detector 10. Specifically, in this example, the radiation source direction is detected using the method described with reference to FIGS. 11 to 17 .

[0052] An example of the processing procedure performed by the radiation source direction calculation unit 11 for detecting the radiation source direction will be described with reference to the flowcharts of Figures 19 and 20. Figure 19 is a flowchart of the processing related to identifying the trigger pixel PxT. In step S101, the radiation source direction calculation unit 11 performs processing to set all pixels to the trigger mode. Specifically, it causes each pixel Px of the radiation source direction detector 10 to start a radiation detection operation.

[0053] In step S102 following step S101, the radiation source direction calculation unit 11 waits until a pixel Px is generated whose photon count number is equal to or greater than a predetermined number. If a pixel Px is generated whose photon count number is equal to or greater than the predetermined number, the radiation source direction calculation unit 11 determines the pixel as a trigger pixel PxT in step S103, and then ends the series of processes in FIG. 19 .

[0054] Fig. 20 is a flowchart of processing for detecting the radiation source direction based on the radiation detection results in the opposing pixel area Ap of the trigger pixel PxT. If multiple trigger pixels PxT are detected by the processing shown in Fig. 19, the radiation source direction calculation unit 11 may perform the processing shown in Fig. 20 for each trigger pixel PxT.

[0055] In step S201, the radiation source direction calculation unit 11 identifies the opposing pixel area Ap of the trigger pixel PxT. Then, in step S202 following step S201, the radiation source direction calculation unit 11 waits for the arrival of a window period, and when the window period arrives, in step S203, starts acquiring the photon count number for each pixel Px per unit period. That is, for each pixel Px in the opposing pixel area Ap, starts acquiring the photon count number for each pixel Px per unit period.

[0056] In step S204 following step S203, the radiation source direction calculation unit 11 waits for the end of the window period, and when the window period has ended, in step S205, generates a histogram of each pixel Px.

[0057] In step S206 following step S205, the radiation source direction calculation unit 11 determines whether the histogram peak value of each pixel Px is equal to or greater than a threshold value, i.e., whether the histogram peak values ​​of all pixels Px in the opposing pixel area Ap are equal to or greater than a threshold value.

[0058] If it is determined in step S206 that the histogram peak value of each pixel Px is not equal to or greater than the threshold value (the condition that the histogram peak value of each pixel Px is equal to or greater than the threshold value is not satisfied), the radiation source direction calculation unit 11 ends the series of processes shown in Fig. 20. This prevents erroneous detection of the radiation source direction due to noise components.

[0059] If it is determined in step S206 that the histogram peak value of each pixel Px is equal to or greater than the threshold value, the radiation source direction calculation unit 11 proceeds to step S207 to identify the pixel Px with the largest histogram peak value. Then, in step S208 following step S207, the radiation source direction calculation unit 11 determines the direction from the identified pixel Px through the trigger pixel as the radiation source direction.

[0060] After executing the process of step S208, the radiation source direction calculation unit 11 ends the series of processes shown in FIG.

[0061] In the following description, the radiation source direction detected by the radiation source direction calculation unit 11 is referred to as the "radiation source direction Dr."

[0062] The method for detecting the radiation source direction Dr is not limited to the method using a histogram as exemplified above, and various other methods are conceivable. For example, a method may be adopted in which the total number of photons counted within a window period in each pixel Px in the opposing pixel area Ap is calculated, and the pixel Px with the largest total number is identified.

[0063] In this case, if the size R (diameter in this example) of the radiation source direction detector 10 is 10 mm, the aforementioned transit time Δt = R / C is 10 mm / 299,729 km / s = 33.36 ps (picoseconds). The time resolution (the aforementioned unit period) of the SPAD element used as the photoelectric conversion element 3 is approximately 1 ps as of 2022, so the distance resolution in this case is approximately 0.3 mm, or 1 / 33.36. Based on this distance resolution, it is conceivable to set the window period for R = 10 mm to, for example, approximately 1 ps. However, in this case, only one of the aforementioned unit periods can be secured within the window period. In other words, in this case, the histogram described above cannot be generated. However, because the time resolution of the SPAD element tends to decrease year by year, it is possible to obtain a time resolution sufficient for histogram generation in a few years.

[0064] [1-3. Size of the Radiation Source Direction Detector] When it is assumed that the information on the detected radiation source direction Dr will be used to estimate the own attitude and position as described below, the radiation source direction detector 10 may have a wide range of sizes, such as a size of about R = 5 m when mounted on a submersible, or a size of about R = 2 mm when mounted on a mobile device.

[0065] Here, we will consider the relationship between the detection accuracy of the radiation source direction Dr and the size R of the radiation source direction detector 10. Fig. 21 is an explanatory diagram of the angular resolution θ derived from the size R of the radiation source direction detector 10 and the pixel size a (size of pixel Px). The angular resolution θ is expressed as θ = tan －１ (a / R).

[0066] 22 shows a table of the angular resolution θ for each combination of pixel size a and size R. Here, the example shows sizes R = 5000 mm, 1000 mm, 300 mm, and 100 mm assumed to be sizes suitable for use in large devices such as submarines, and sizes R = 10 mm, 5 mm, and 2 mm assumed to be sizes suitable for use in small portable devices such as smartphones. Furthermore, the example shows pixel size a = 10000 μm, 1000 μm, 100 μm, 10 μm, 3 μm, and 1 μm.

[0067] As can be seen from the above explanation, the angle error due to the solar diameter is ±0.266 degrees, so if the angular resolution is higher than ±0.027 degrees shown below the bold dotted line in the figure, for example, the resolution is about 10 × 10 pixels, making it easy to estimate the center of the Gaussian distribution shown in Figure 15. In this case, a minimum resolution of three pixels is sufficient to roughly estimate the center, so there is no particular limitation to the above resolution of 10 × 10 pixels, and it is merely a guideline.

[0068] In the figure, the area above the thick solid line is insufficient in precision, and the area below the thick dashed dot line is over-specified in terms of precision, which is expected to result in low mass productivity and is unlikely to be adopted.

[0069] [1-4. Reaction rate of scintillator] Fig. 23 is a diagram showing in tabular form the relationship between scintillator materials and reaction rates. Here, the rise time τ1 and decay time τ2 in the diagram are as shown in Fig. 24, where the rise time τ1 corresponds to the time from the incidence of radiation until the detected intensity (amount of light emission) reaches its peak, and the decay time τ2 corresponds to the decay time from the peak of the detected intensity.

[0070] FIG. 23 illustrates the characteristics of CsBr, CdS:In, NE111, Naton136, NE102A, LaBr3:Ce, HfO2, CsGd2F7:Ce, and NaI(TI), but materials with shorter rise time τ1 and decay time τ2 are being developed one after another, and the present invention is not limited to these materials.

[0071] [1-5. Another Example of a Radiation Source Direction Detector] While the above describes an example of the radiation source direction detector 10 in which the radiation-to-light conversion unit 2 is arranged outside the photoelectric conversion elements 3, it is also possible to employ a structure in which the radiation-to-light conversion unit 2 is arranged inside the photoelectric conversion elements 3, as in the radiation source direction detector 10A shown in Fig. 25. By using such a radiation source direction detector 10A, as shown in Fig. 26, the front end unit FE is arranged facing outward, eliminating the need to provide space for routing wiring from the front end unit FE from inside the radiation source direction detector 10A to the outside, which has the advantage of preventing blind spots in radiation detection. Another advantage is that heat generated by the pixel circuits and the front end unit FE can be easily dissipated.

[0072] In addition, although the above example shows the radiation source direction detector 10 being formed in an approximately spherical shape, the shape of the radiation source direction detector 10 is not limited to an approximately spherical shape, and other three-dimensional shapes such as a polyhedron or a cube can be adopted.

[0073] For example, it is conceivable to use a radiation source direction detector 10B shaped like a soccer ball as shown in Fig. 27. This radiation source direction detector 10B has a soccer ball-shaped polyhedron, with pixels Px arranged on each surface of the polyhedron. In this case, a flexible substrate Bs having a shape as shown in Fig. 28, which is a two-dimensional development of the soccer ball shape, is used, and a plurality of radiation detection units 9 and a front end FE are mounted on this flexible substrate Bs in the same manner as described above in Fig. 8, and the flexible substrate Bs is then bent and bonded to form the radiation source direction detector 10B shaped like a soccer ball as shown in Fig. 27.

[0074] 29 shows an example of a cubic radiation source direction detector 10C. The method for detecting the radiation source direction Dr is basically the same in the case of a cubic radiation source direction detector as in the case of a sphere. However, while the passing time Δt and window period are uniform for all pixels Px in the case of a sphere, the passing time Δt from the trigger pixel PxT to the counter pixel PxO (the pixel Px on which radiation is incident through the center) differs for each pixel Px. Therefore, in this case, a table of passing times Δt is prepared for each pixel Px. The passing time Δt for each pixel Px can be calculated in advance using common calculations such as trigonometric functions.

[0075] In the case of a cubic radiation source direction detector 10C, it is not possible to position pixels Px on any of the eight vertices or any of the sides. In other words, blind spots in radiation detection occur at these positions. For this reason, as shown in Fig. 30, for example, if the target radiation source is located on an extension line between vertices that face each other through the center of the radiation source direction detector 10C, it is not possible to detect the radiation source direction with high accuracy.

[0076] However, even in this case, a Gaussian distribution of the detected intensity (detected dose) as explained above in Fig. 15 is obtained in the opposing pixel area Ap shown in Fig. 30. Fig. 31 shows an example of the distribution of the detected intensity in the opposing pixel area Ap shown in Fig. 30. In the figure, the parts indicated by thick lines represent blind spots in radiation detection.

[0077] In this case, it is possible to identify whether or not radiation has passed through a blind spot by performing a process to estimate the center of the intensity distribution from information about the intensity distribution within the opposing pixel area Ap obtained from the radiation detection results for each pixel Px within the window period. In other words, this makes it possible to detect the direction of the radiation source with high accuracy even when the radiation passes through the blind spot → center → blind spot.

[0078] [1-6. Other Alternative Configuration Examples] As mentioned above, the energy of solar neutrinos decays at night (see FIG. 9). Therefore, it may be possible to increase the radiation detection sensitivity of pixel Px at night compared to daytime.

[0079] For example, a radiation source direction detecting unit 1D shown in Fig. 32 may be configured to include a control unit 15 that controls the radiation detection sensitivity of each pixel Px based on time information (current time information) measured by a timer 16. Specifically, the control unit 15 determines whether it is nighttime or daytime based on the time information, and, if it is determined that it is nighttime, controls the radiation source direction detector 10 to increase the detection sensitivity of each pixel Px compared to that in daytime, i.e., to increase the gain of the gain circuit described above.

[0080] This makes it possible to control the radiation detection sensitivity of pixel Px to an appropriate sensitivity according to the detected radiation energy when the target radiation source is the sun, i.e., when the radiation source is a light source whose detected radiation energy changes over time, thereby preventing the detection accuracy of the radiation source direction from varying over time and improving the stability of the detection accuracy of the radiation source direction.

[0081] Furthermore, although the above describes an example in which the time window method is used to separate noise components, it is also possible to use a method for separating noise components that utilizes differences in the attenuation characteristics (attenuation τ2 characteristics) of the radiation-to-light conversion unit 2 depending on the type of radiation.

[0082] Specifically, some scintillator materials have different attenuation characteristics depending on the type of radiation, as illustrated in FIG. 33 . For example, when targeting neutrons among the α-rays, neutrons (fast neutrons), and gamma rays illustrated in the figure, it is determined whether the attenuation characteristics of the radiation intensity observed at pixel Px match the attenuation characteristics specific to neutron rays. If they match, the radiation is determined to be from the target radiation source, and the radiation detection result is used to estimate the radiation source direction. One specific method is to distinguish based on the attenuation level at a predetermined time after the peak level. For example, in the example shown in the figure, it is possible to determine whether the radiation is a neutron based on whether the level 200 ns after the peak level is approximately 1 / 1000 of the peak level. In the example shown in the figure, if the attenuation 200 ns after the peak level is approximately 1 / 600, it can be determined to be an α-ray, and if the attenuation is approximately 1 / 8000, it can be determined to be a gamma ray.

[0083] <2. Attitude Estimation Device> [2-1. Attitude Estimation Device as a First Example] For example, an IMU (Inertial Measurement Unit) that combines an acceleration sensor, an angular velocity sensor, an orientation sensor, etc. is known, and a technology for detecting the attitude and position of a vehicle based on information detected by the IMU is also known.

[0084] An acceleration sensor can calculate distance traveled by performing a second-order integration of the detected acceleration signal. It can also detect gravitational acceleration, making it possible to detect the vertical direction on Earth. Furthermore, by using a three-axis acceleration sensor, it is possible to detect acceleration in the direction of travel. Furthermore, an angular velocity sensor can calculate angular change by performing a first-order integration of the detected angular velocity signal.

[0085] However, with regard to acceleration, the S / N (signal-to-noise ratio) deteriorates due to vibration components, making it difficult to accurately detect gravitational acceleration or acceleration in the direction of travel. Also, with regard to angular velocity, it is difficult to accurately detect changes in angle due to drift and temperature characteristics. Furthermore, with regard to direction sensors, errors can occur in the detected direction information due to the influence of external magnetic fields depending on the usage environment.

[0086] Therefore, attempts have been made to suppress errors by fusing the outputs of multiple sensors, such as acceleration sensors, angular velocity sensors, and orientation sensors, and performing correction using various correction filters, such as complementary filters and Kalman filters.

[0087] However, even if correction is performed using the correction filter as described above, there is a limit to how much error can be suppressed.

[0088] Here, the radiation source direction detecting unit 1 according to the embodiment can detect the radiation source direction Dr with high accuracy for a target radiation source whose position is known, such as the sun, etc. As can be understood from the above description, the radiation source direction detecting unit 1 according to the embodiment can correctly detect the radiation source direction Dr for the target radiation source regardless of the posture of the device itself.

[0089] In this embodiment, we propose a method for correcting errors occurring in the detection information of the IMU by utilizing the characteristics of the radiation source direction detecting unit 1. Specifically, we propose a method for correcting errors occurring in the detection information of the IMU based on the information on the radiation source direction Dr detected by the radiation source direction detecting unit 1.

[0090] A specific method will be described with reference to Figures 34 to 37. First, in this example, information on the reference radiation source direction Dsr is used to correct the detection information of the IMU. This reference radiation source direction Dsr is obtained by determining the direction of a radiation source of interest whose position is known, and identifying the direction based at least on the current position information of the radiation source. In this example, the target radiation source is the sun, and therefore current time information is required in addition to current position information. If the self-position can be identified by the latitude and longitude of the Earth, the direction of the sun can be identified based on the latitude and longitude information of the current position and current time information. In this example, the sun direction identified based on the current position information and current time information is used as the reference radiation source direction Dsr.

[0091] Here, the reference radiation source direction Dsr determined from the current position information and current time information as described above is information indicating the direction of the sun, which is the radiation source of interest, relative to a certain position on Earth, and is, so to speak, directional information in the world coordinate system. Once this reference radiation source direction Dsr is identified, the direction of gravity and the azimuth directions of east, west, south, and north can be identified from the reference radiation source direction Dsr. In this example, the detection signals of the acceleration sensor, angular velocity sensor, and azimuth sensor in the IMU are calibrated based on the gravity direction dg and azimuth direction (specifically, the reference azimuth direction among east, west, south, and north; in this example, the direction in which north is located; hereinafter referred to as the "reference azimuth direction dd") identified from the reference radiation source direction Dsr, thereby correcting errors occurring in the detection information of the IMU.

[0092] Because the IMU detection information is detected in the local coordinate system of the device in which the IMU is implemented, the gravity direction dg and the reference azimuth direction dd identified from the reference radiation source direction Dsr as described above cannot be used as they are to calibrate the IMU detection information. For this reason, in this example, the gravity direction dd and the reference azimuth direction dg are converted from directional information in the world coordinate system to directional information in the local coordinate system before being used to calibrate the IMU detection information.

[0093] The radiation source direction Dr detected by the radiation source direction detection unit 1 is used to convert the gravity direction dd and the reference azimuth direction dg into the local coordinate system. This radiation source direction Dr is also detection information in the local coordinate system of the device, similar to the detection information of the IMU.

[0094] 34A and 34B are conceptual diagrams of the radiation source direction Dr detected as direction information in a local coordinate system. As can be seen from Fig. 34A and Fig. 34B, the radiation source direction Dr is considered to be direction information in a local coordinate system, and therefore its value changes depending on the attitude of the device.

[0095] In converting the gravity direction dd and the reference orientation direction dg into information in the local coordinate system, the direction difference Ddg between the reference radiation source direction Dsr and the gravity direction dg and the direction difference Ddd between the reference radiation source direction Dsr and the reference orientation direction dd are calculated as shown in Fig. 35. Then, as shown in Fig. 36, the direction specified by applying a directional offset by the direction difference Ddg to the radiation source direction Dr is calculated as the gravity direction dgl in the local coordinate system, and the direction specified by applying a directional offset by the direction difference Ddd to the radiation source direction Dr is calculated as the reference orientation direction ddl in the local coordinate system.

[0096] 37 is a block diagram showing a configuration example of a position and orientation estimation device 20 as a first example for realizing the correction method as the embodiment described above. In the following explanation, parts that are similar to parts that have already been explained will be assigned the same reference numerals and explanations thereof will be omitted.

[0097] As shown in the figure, the position and attitude estimation device 20 includes a radiation source direction detection unit 1, as well as an acceleration sensor 21, an angular velocity sensor 22, a direction sensor 23, a GNSS (Global Navigation Satellite System) sensor 24, a correction filter unit 25, a self-position and attitude estimation unit 26, a gravity and direction true value calculation unit 27, a timer unit 28, and a reference radiation source direction calculation unit 29. Note that although this example shows the radiation source direction detection unit 1 as a detector for the radiation source direction Dr, the radiation source direction detection unit 1D described above can also be used.

[0098] The acceleration sensor 21, the angular velocity sensor 22, and the orientation sensor 23 are examples of sensors included in the IMU. In this example, the acceleration sensor 21 and the angular velocity sensor 22 detect acceleration and angular velocity along three axes (X-axis, Y-axis, and Z-axis), respectively. The orientation sensor 23 is configured as a sensor that detects the orientation (azimuth direction) in which the vehicle is facing based on geomagnetism. In this example, a three-axis orientation sensor is used as the orientation sensor 23.

[0099] The correction filter unit 25 is configured to be able to perform error correction using known techniques such as a Kalman filter, a complementary filter, or a Madwick filter for the acceleration information detected by the acceleration sensor 21, the angular velocity information detected by the angular velocity sensor 22, and the orientation information detected by the orientation sensor 23. The error correction performed here includes correction of errors due to the vibration components described above for acceleration, correction of errors due to drift and temperature characteristics described above for angular velocity, and correction of errors due to the external magnetic field described above for orientation. The error correction process includes compensation for phase delay using a filter and gain adjustment to accommodate differences in gain between input and output.

[0100] The correction filter unit 25 of this embodiment performs error correction for acceleration, angular velocity, and orientation by using the above-mentioned gravity direction dgl and reference orientation direction ddl as the true values ​​of the gravity direction and reference orientation direction, respectively, but this will be explained later.

[0101] The self-position / attitude estimation unit 26 estimates the position and attitude of itself (the device itself) based on the acceleration, angular velocity, and orientation information input via the correction filter unit 25 and the current position information detected by the GNSS sensor 24. Note that the method for estimating the device's position and attitude based on the IMU detection information and current position information may be any known method, and is not limited to a specific method. At this time, the current position information from the GNSS sensor 24 is used to identify the device's initial position, etc.

[0102] The reference radiation source direction calculation unit 29 calculates the reference radiation source direction Dsr based on the current position information detected by the GNSS sensor 24 and the current time information measured by the clock unit 28. For clarity, the relationship between the position on Earth, the time, and the position of the sun is known, and the reference radiation source direction calculation unit 29 calculates the reference radiation source direction Dsr with respect to the sun based on information indicating this known relationship.

[0103] The gravity and orientation true value calculator 27 calculates the gravity direction dgl and the reference orientation direction ddl in the local coordinate system based on the radiation source direction Dr detected by the radiation source direction detection unit 1 and the reference radiation source direction Dsr calculated by the reference radiation source direction calculator 29. Specifically, the gravity and orientation true value calculator 27 calculates the gravity direction dg and the reference orientation direction dd (north in this example) in the world coordinate system based on the reference radiation source direction Dsr. At this time, since the orientation is not determined with respect to a plane perpendicular to the radiation source direction Dr, the correction filter unit 25 inputs either or both of orientation information from the orientation sensor 23 and gravity direction information based on the detection signal of the acceleration sensor 21, and reconstructs the world coordinate system based on the input information. Then, the gravity / orientation true value calculation unit 27 calculates the direction difference Ddg between the reference radiation source direction Dsr and the gravity direction dg, and the direction difference Ddg between the reference radiation source direction Dsr and the reference orientation direction dd, and then determines the direction identified by applying a direction offset by the direction difference Ddg to the radiation source direction Dr as the gravity direction dgl in the local coordinate system, and also determines the direction identified by applying a direction offset by the direction difference Ddd to the radiation source direction Dr as the reference orientation direction ddl in the local coordinate system.

[0104] The correction filter unit 25 calibrates the acceleration detected by the acceleration sensor 21, the angular velocity detected by the angular velocity sensor 22, and the orientation detected by the orientation sensor 23, using the gravity direction dgl and the reference orientation direction ddl calculated by the gravity / orientation true value calculation unit 27 as the true values ​​of the gravity direction and the reference orientation, respectively. This calibration is performed using a filter such as a Kalman filter, a complementary filter, or a Madgwick filter to correct errors occurring in the acceleration, angular velocity, and orientation. This correction makes it possible to distinguish between the motion acceleration of the acceleration sensor 21 and the gravitational acceleration. It also makes it possible to correct errors due to drift and temperature offset of the angular velocity sensor 22. Furthermore, it makes it possible to correct errors due to external magnetic fields of the orientation sensor.

[0105] The self-position / attitude estimation unit 26 estimates the position and attitude of the vehicle based on the acceleration, angular velocity, and orientation information corrected by the correction filter unit 25 as described above, thereby improving the accuracy of estimating the self-position and attitude.

[0106] In the above example, not only the attitude but also the position of the robot is estimated based on the corrected IMU detection information, but in this embodiment, it is not essential to estimate the robot's position.

[0107] Although the above describes an example in which the target radiation source is the sun, other radiation sources with known positions, such as a nuclear reactor, can also be selected as the target radiation source. For example, in the case of a nuclear reactor, the reference radiation source direction Dsr can be calculated by knowing the positional relationship between the current position of the device and the reactor, eliminating the need to use current time information. As can be understood from this point of view, it is not essential to use current time information when calculating the reference radiation source direction Dsr. Furthermore, although the above describes an example in which the current position information used to calculate the reference radiation source direction Dsr is detected by the GNSS sensor 24, the current position information used to calculate the reference radiation source direction Dsr may be externally input information, such as a user operation input, and it is not essential for the self-position / orientation estimation unit 26 to include the GNSS 24 when calculating the reference radiation source direction Dsr.

[0108] Here, regarding the correction of the detection information of the IMU, it is conceivable to calibrate the correction parameters before actual use, but the correction filter unit 25 can also perform this calibration using information on the radiation source direction Dr detected by the radiation source direction detection unit 1. In this case, during actual use after calibration, the correction filter unit 25 will continuously correct the detection information of the IMU based on the radiation source direction Dr as described above.

[0109] [2-2. Second Example of Attitude Estimation Device] Here, when the radiation source direction detection unit 1 is used for error correction of the detection information of the IMU, it is desirable to perform delay compensation taking into consideration the delay time required for the radiation source direction detection unit 1 to detect the radiation source direction Dr, specifically, the delay time from when radiation is incident on the trigger pixel PxT to when the radiation is detected by the pixel Px on the opposite side.

[0110] FIG. 38 is an explanatory diagram of the delay time DL to be compensated. As shown in the figure, a delay time Δti also occurs on the IMU side, and the delay time DL to be compensated for is determined taking this delay time Δti into consideration. Since the delay time on the radiation source direction detecting unit 1 side is a rise time τ1 (scintillator response time), the delay time DL can be calculated as DL = Δti - τ1. Note that FIG. 38 is merely an example of the delay time DL, and depending on the respective delay times, the delay time DL may exceed the transit time Δt.

[0111] FIG. 39 is a block diagram showing a configuration example of a position and orientation estimation device 20A as a second example that compensates for the delay time DL. The difference from the position and orientation estimation device 20 shown in FIG. 37 is that a correction filter unit 25A is provided instead of the correction filter unit 25. The correction filter unit 25A differs from the correction filter unit 25 in that it includes a delay compensation unit 31. The delay compensation unit 31 performs delay compensation based on the delay time DL for the acceleration detected by the acceleration sensor 21, the angular velocity detected by the angular velocity sensor 22, and the orientation detected by the orientation sensor 23. Specifically, a delay equivalent to the delay time DL is applied to the acceleration, angular velocity, and orientation. This allows appropriate compensation for the delay time associated with the detection of the radiation source direction Dr, thereby improving the estimation accuracy of the device's own position and orientation.

[0112] 40 is a block diagram showing a configuration example of a position and orientation estimation device 20B as a third example. The third example is a countermeasure example when the radiation source direction detecting unit 1 detects a small amount of radiation.

[0113] Position and orientation estimation device 20B differs from position and orientation estimation device 20 shown in FIG. 37 in that correction filter unit 25B is provided instead of correction filter unit 25, and control unit 32 is added.

[0114] The control unit 32 counts the number of times the radiation source direction Dr is detected per unit time by the radiation source direction detecting unit 1, and if the number of detections does not reach a predetermined number, controls the correction filter unit 25B to perform correction using a correction method different from correction based on information about the radiation source direction Dr detected by the radiation source direction detecting unit. Specifically, if the number of detections does not reach the predetermined number, the control unit 32 causes the correction filter unit 25B to perform correction using an existing publicly known method, rather than the correction method based on the gravity direction dgl and the reference azimuth direction ddl.

[0115] As a result, during a period when the radiation source direction detecting unit 1 is unable to detect the radiation source direction Dr or the number of detections is reduced for some reason, correction based on the radiation source direction Dr is stopped, and the self-position and self-orientation are estimated using IMU detection information corrected by a different correction method, specifically an existing correction method. Therefore, even when the radiation source direction detecting unit 1 is unable to detect the radiation source direction Dr or the number of detections is reduced, the self-position and self-orientation estimation results can be continuously output. Note that if the period during which correction based on the radiation source direction Dr is not performed is short, the influence of gyro drift and the like is small, and the errors in the self-position and self-orientation estimation results do not become excessive.

[0116] 3. Application Examples of the Orientation Estimation Device Various applications are conceivable for the position and orientation estimation device 20 according to the embodiment. Note that, although application examples of the position and orientation estimation device 20 are shown below, it is also possible to use the position and orientation estimation device 20A or the position and orientation estimation device 20B instead of the position and orientation estimation device 20.

[0117] 41 shows a schematic configuration example of a smartphone 50 to which the position and orientation estimation device 20 is applied. In this case, the smartphone 50 includes a motion analysis unit 40 that performs motion analysis processing based on information about the position and orientation estimated by the position and orientation estimation device 20. Examples of the motion analysis processing in this case include tracking of the smartphone's own position (calculation of a movement trajectory) and gesture recognition processing.

[0118] The position and orientation estimation device 20 may also be applied to mobile computer devices other than smartphones, such as tablet terminals and notebook PCs (personal computers).

[0119] 42 shows a schematic configuration example of a camera 51 to which the position and orientation estimation device 20 is applied. The camera 51 has an imaging unit (not shown) that obtains a captured image using an image sensor, and also includes a blur correction unit 41 that performs blur correction processing based on information about the orientation estimated by the position and orientation estimation device 20. The blur correction processing in this case is blur correction processing for the captured image, and can be, for example, electronic blur correction processing by cropping the captured image, or optical blur correction processing. The blur correction here also includes a function for maintaining horizontality.

[0120] 43 shows a schematic configuration example of a moving body 52 to which the position / attitude estimation device 20 is applied. Examples of the moving body 52 include vehicles such as automobiles and motorcycles, as well as flying bodies such as drones and airplanes, submarines and ships, rockets and spacecraft, and underground shield tunneling machines. The moving body 52 is equipped with an attitude control unit 42 that performs attitude control processing based on information about the attitude estimated by the position / attitude estimation device 20. Examples of attitude control processing in this case include processing for stabilizing attitude, such as control processing to prevent skidding in automobiles, control processing to prevent tipping over in motorcycles, and control processing to prevent crashes in drones.

[0121] The radiation source direction detection unit 1 can detect the radiation source direction Dr with high accuracy even underground, underwater, or in the sky (including outer space). Therefore, even if the moving body to which the position / attitude estimation device 20 is applied is an underground shield tunneling machine, a submersible, or a spaceship, the position / attitude estimation device 20 can obtain highly accurate attitude and position information.

[0122] 4. Grid Array System By distributing devices incorporating the position and orientation estimation device 20 at various locations on Earth, it is possible to realize a groundbreaking observation system not previously available. As an example, assuming that users of smartphones 50 equipped with the position and orientation estimation device 20 are located all over the world, as shown in FIG. 44 , the radiation source direction detecting units 1 of the embodiment can be considered to be arranged in a grid array around the world. By utilizing the radiation source direction detecting function of multiple grid-arrayed radiation source direction detecting units 1, information on the solar neutrino dose detected at various locations on Earth can be collected. By determining the attenuation ratio (or attenuation amount) of the dose of solar neutrinos as they pass from the dayside of the Earth through the Earth's interior to the nightside at various locations, an image showing the distribution of the attenuation ratio can be obtained. Images showing the distribution of such attenuation ratios enable detailed imaging observations (fluoroscopic observations) of the Earth's mantle, core, and crust.

[0123] FIG. 45 shows an example of a system configuration in this case. Information on the detected dose from each smartphone 50 is collected by a server device 55 via a network NT such as the Internet, as shown. At this time, information on the detected radiation source direction Dsd and location information of each smartphone 50 are also collected from the smartphones 50, along with the detected radiation dose information. Based on the smartphone 50 location information and the detected radiation source direction Dsd information, the server device 55 identifies each pair of smartphones 50 on the dayside and nightside that detected the same solar neutrino. Then, for each identified pair of smartphones 50, the dose attenuation ratio is calculated and an image is generated in which the calculated attenuation ratio is mapped. This makes it possible to obtain a perspective image of the Earth's interior using radiation from the sun.

[0124] Further, an example of an observation using a grid array is the observation of a supernova explosion as shown in FIG. 46 . In this example, it is assumed that each smartphone 50 (not limited to a smartphone 50, but any device equipped with a position / attitude estimation device 20) recognizes its own accurate position and attitude (vertical direction: direction of gravity) based on solar neutrinos. Two or more smartphones 50 detect the direction of a radiation source, with the supernova as the target radiation source. Then, based on the information on the direction of the supernova detected by these smartphones 50 and the position information of each smartphone 50, the position of the supernova is calculated by triangulation. Specifically, first, the baseline length d is calculated based on the position information of each smartphone 50. Then, when each smartphone 50 detects a unique radiation source other than the sun (a supernova), it performs a radiation source direction detection process with the unique radiation source as the target radiation source. Furthermore, based on the information on the radiation source direction of the supernova detected by these smartphones 50, the angle α between the baseline of one smartphone 50 and the detected radiation source direction and the angle β between the baseline of the other smartphone 50 and the detected radiation source direction are calculated, and the position of the supernova is calculated using triangulation based on these angles α and β and the baseline length d. By selecting two devices that are sufficiently separated on Earth, it is possible to ensure a sufficiently long baseline length d, allowing the position of the supernova to be determined with high accuracy.

[0125] An example of a system configuration in this case is shown in Figure 47. As shown in the figure, the server device 55 in this case has a receiving unit F1 and a radiation source position calculation unit F2. The receiving unit F1 receives, via the network NT, information on the radiation source direction identified from the detection results of the radiation source direction detection unit 1 (information on the detected radiation source direction Dsd in this example) from multiple smartphones 50 located at different positions on the Earth. The receiving unit F1 in this example receives not only the radiation source direction information but also the position information of each smartphone 50 from the multiple smartphones 50.

[0126] The radiation source position calculation unit F2 performs calculations to identify the position of the radiation source based on the radiation source direction information received by the receiving unit F1 from the multiple smartphones 50 and the position information of the multiple smartphones 50. Specifically, the base line, base line length d, angle α, and angle β are determined using the above-mentioned method, and the position of the supernova is calculated using triangulation based on this information.

[0127] It is not necessary for each smartphone 50 to detect its own current location. For example, if the location of each smartphone 50 is known, information about that location may be used. Furthermore, if it is assumed that each smartphone 50 is fixedly positioned (i.e., its orientation does not change), the radiation source direction Dr detected by the radiation source direction detection unit 1 can be made to indicate the direction in the world coordinate system as is. In this case, it is also possible to have the server device 55 receive the radiation source direction Dr instead of the detected radiation source direction Dsd after coordinate conversion.

[0128] 5. Modifications Note that embodiments are not limited to the specific examples described above, and various modified configurations are possible. For example, the scintillator used as the radiation-to-light conversion unit 2 may be one having a current-carrying circuit formed therein for actively controlling the atomic arrangement. In this case, the scintillator is configured so that the atomic arrangement can be controlled by applying current. For example, a piezoelectric material may be used as a specific material. For example, the neutrino collision probability can be increased by shifting and aligning the B site in one direction. Alternatively, the neutrino collision probability can be increased by vibrating the B site at the same frequency as the target neutrino's oscillation frequency. Furthermore, it is possible to vibrate the B site at various oscillation frequencies to search for a frequency with a high neutrino collision probability and use that frequency. It is also possible to maintain current flow just above the light emission threshold to increase the light emission efficiency in neutrino collisions. Note that a configuration in which the B sites are arranged alternately in layers to increase the neutrino collision probability is also possible.

[0129] Although the above example illustrates the use of information on the reference radiation source direction Dsr in correcting the detection information of the IMU, it is not essential to use information on the reference radiation source direction Dsr in correcting the detection information of the IMU. For example, it is conceivable to use the change (direction and amount of change) per unit time of the radiation source direction Dr detected by the radiation source direction detection unit 1 as a reference change, calculate an error between this reference change and the change per unit time of the attitude (direction) calculated based on the detection information of the IMU, and correct the detection information of the IMU using a correction filter so as to cancel this error.

[0130] 6. Summary of the Embodiments As described above, the radiation source direction detecting device (radiation source direction detecting unit 1, 1D) according to the embodiment includes a radiation detection section (radiation source direction detector 10, 10A, 10B, 10C) in which a plurality of radiation-detecting pixels (Px) are discretely arranged in three dimensions, and a calculation section (radiation source direction calculation section 11) that performs calculations to identify the direction of a radiation source based on the radiation detection results from the plurality of pixels in the radiation detection section. By discretely arranging a plurality of radiation-detecting pixels in three dimensions as described above, it is possible for radiation arriving from a certain direction to pass through a certain pixel and then pass through another pixel. Therefore, for example, if a certain pixel detects radiation and then another pixel detects radiation, it is possible to estimate that the radiation arrived from a direction passing through these two pixels. In other words, it is possible to identify the direction of a radiation source based on the radiation detection results from the plurality of pixels. The radiation source direction detecting device of this embodiment makes it possible to realize a radiation detection device that can detect the direction of a radiation source.

[0131] In the radiation source direction detecting device according to the embodiment, each pixel comprises a radiation / light conversion unit (2) that emits light in response to radiation, and a photoelectric conversion element (3) that detects the light emitted by the radiation / light conversion unit, thereby making it possible to obtain an electrical signal indicating whether radiation has been detected.

[0132] Furthermore, in the radiation source direction detecting device according to the embodiment, a SPAD element is used as the photoelectric conversion element. Since the SPAD element is an element capable of photon counting, the above configuration makes it possible to detect the amount of incident radiation particles. Furthermore, recent and future improvements in the characteristics of the SPAD element are expected to improve the radiation detection speed and reduce noise in radiation detection.

[0133] Furthermore, in the radiation source direction detecting device according to the embodiment, the radiation / light converting unit is a scintillator. Radiation / light conversion using a scintillator is advantageous in terms of luminous efficiency. Therefore, the radiation detection accuracy can be improved, and the radiation source direction detection accuracy can be improved.

[0134] Furthermore, in the radiation source direction detecting apparatus according to the embodiment, the radiation detection unit (radiation source direction detectors 10, 10A, 10B) has a spherical or polyhedral portion, and pixels are arranged on the surface of the spherical portion or on each surface of the polyhedral portion. This results in the pixels being arranged three-dimensionally and discretely in the radiation detection unit. This makes it possible to realize a radiation detection device that can detect the direction in which a radiation source is located.

[0135] Furthermore, in the radiation source direction detecting device according to the embodiment, in response to radiation detection by a certain pixel, the calculation unit acquires radiation detection results for the opposite pixel of the trigger pixel that detected the radiation during a predetermined window period after the radiation detection by the trigger pixel. If it determines based on the radiation detection results that the radiation detection intensity of the opposite pixel during the window period was not equal to or greater than a threshold, the calculation unit does not identify the radiation source direction based on the radiation detection results (see FIG. 20 ). This makes it possible to narrow down the target radiation source to only radiation that passes from the trigger pixel, passes through the center of the radiation detection unit, and enters the opposite pixel, even if the target radiation source emits a large amount of radiation, such as the sun. In other words, it is possible to prevent the detection results of radiation from a radiation source other than the target radiation source, which may be considered noise, from being mistakenly used in detecting the radiation source direction. This improves the accuracy of radiation source direction detection.

[0136] Furthermore, in the radiation source direction detecting device according to the embodiment, the calculation unit acquires radiation detection results within a window period for each pixel within a facing pixel area (Ap) that includes the facing pixel of the trigger pixel and its surrounding pixels, identifies the pixel within the facing pixel area that detected the greatest radiation intensity within the window period, and determines the direction from the identified pixel through the trigger pixel as the radiation source direction. This makes it possible to identify the pixel within the facing pixel area that detected radiation emitted from the center of the radiation source. This makes it possible to prevent errors in detecting the radiation source direction due to the finite size of the radiation source, thereby improving the accuracy of detecting the radiation source direction.

[0137] Furthermore, the radiation source direction detecting device (radiation source direction detecting unit 1D) according to this embodiment includes a sensitivity control unit (control unit 15) that controls the radiation detection sensitivity of each pixel based on time information. This makes it possible to control the radiation detection sensitivity of each pixel to an appropriate sensitivity according to the detected radiation energy when the target radiation source is a light source whose detected radiation energy changes over time, such as the sun. This prevents the detection accuracy of the radiation source direction from changing over time, thereby improving the stability of the detection accuracy of the radiation source direction.

[0138] Furthermore, in the radiation source direction detecting device according to the embodiment, the radiation detection unit has a three-dimensional structure formed by bending a flexible substrate on which a plurality of pixels are mounted, thereby improving the ease of assembly of the radiation detection unit.

[0139] Furthermore, in the radiation source direction detecting device according to the embodiment, the pixels in the radiation detection unit are formed on a substrate by transfer technology, which makes it easier to miniaturize the pixels and reduces the size and weight of the radiation source direction detecting device.

[0140] In the radiation source direction detecting device according to the embodiment, a current-carrying circuit is formed in the scintillator to actively control the atomic arrangement, thereby improving the radiation detection sensitivity and the radiation source direction detection accuracy.

[0141] The radiation source direction detecting method of the embodiment is a radiation source direction detecting method that performs a calculation to identify the direction of a radiation source based on radiation detection results from a plurality of pixels in a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions. This radiation source direction detecting method can also achieve the same functions and effects as the radiation source direction detecting device of the embodiment described above.

[0142] An attitude estimation device (position / attitude estimation device 20, 20A, 20B) according to an embodiment includes a radiation source direction detection unit (radiation source direction detection unit 1, 1D) having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of a radiation source based on radiation detection results from the plurality of pixels in the radiation detection unit, an attitude estimation unit (self-position / attitude estimation unit 26) that estimates at least its own attitude based on detection information from an IMU, and a correction unit (correction filter unit 25, 25A, 25B) that corrects errors occurring in the detection information from the IMU based on the information on the direction of the radiation source detected by the radiation source direction detection unit. If the radiation source detected by the radiation source direction detection unit is a radiation source whose position is known, such as the sun, it is possible to identify an absolute direction in which the device is facing based on the radiation source direction detected by the radiation source direction detection unit. Therefore, by using the information on the radiation source direction detected by the radiation source direction detection unit, it is possible to correct errors that occur in the detection information of the IMU, such as detection errors in acceleration, angular velocity, and orientation, etc. Therefore, according to the attitude estimation device of the embodiment, the accuracy of attitude estimation can be improved by estimating its own attitude based on the detection information of the IMU that has been corrected in this way.

[0143] In addition, in the posture estimation device according to the embodiment, the position of the radiation source is known, and the posture estimation device includes a reference radiation source direction acquisition unit (reference radiation source direction calculation unit 29) that acquires the radiation source direction identified based on at least its own current position information as a reference radiation source direction, and the correction unit corrects errors occurring in the IMU detection information based on information about the reference radiation source direction acquired by the reference radiation source direction acquisition unit and the radiation source direction detected by the radiation source direction detection unit. Using the above-described reference radiation source direction and the radiation source direction information detected by the radiation source direction detection unit, it is possible to estimate errors occurring in posture-related detection information among the IMU detection information. Therefore, with the above configuration, errors occurring in the IMU detection information can be appropriately corrected, thereby improving the posture estimation accuracy.

[0144] Furthermore, in the posture estimation device according to the embodiment, the radiation source is the sun, the reference radiation source direction acquisition unit acquires the sun's direction identified based on the current position information and current time information as the reference sun direction, and the correction unit corrects errors occurring in the IMU's detection information based on the reference sun direction acquired by the reference radiation source direction acquisition unit and the radiation source direction information detected by the radiation source direction detection unit. This makes it possible to estimate errors occurring in the IMU's detection information related to posture, based on the sun's direction. Therefore, errors occurring in the IMU's detection information can be appropriately corrected, thereby improving the posture estimation accuracy.

[0145] Furthermore, in the attitude estimation device according to the embodiment, the correction unit performs correction using any one of a Kalman filter, a complementary filter, and a Madgwick filter. The Kalman filter, the complementary filter, and the Madgwick filter are suitable as correction filters for correcting the IMU detection information. Therefore, errors occurring in the IMU detection information can be appropriately corrected, thereby improving the attitude estimation accuracy.

[0146] In the posture estimation device according to the embodiment, the correction unit calibrates the correction parameters based on the information on the direction of the radiation source detected by the radiation source direction detection unit, and continues to perform the correction during the period after the calibration, thereby further reducing errors in the information detected by the IMU.

[0147] Furthermore, in the posture estimation device according to the embodiment, the self-position is estimated based on the detection information of the IMU that has been corrected by the correction unit, thereby improving the accuracy of the self-position estimation.

[0148] Furthermore, the posture estimation device (position / posture estimation device 20B) according to this embodiment includes a correction control unit (control unit 32) that, when the number of times per unit time the radiation source direction detection unit detects the radiation source direction is less than a predetermined number, controls the correction unit to perform a correction using a correction method different from the correction based on the radiation source direction information detected by the radiation source direction detection unit. As a result, during a period when the radiation source direction detection unit is unable to detect the radiation source direction or the number of detections is reduced for some reason, the correction based on the radiation source direction information detected by the radiation source direction detection unit is stopped, and posture estimation is performed using IMU detection information corrected using a different correction method (e.g., an existing correction method, etc.). Therefore, posture estimation results can be continuously output even when the radiation source direction detection unit is unable to detect the radiation source direction or the number of detections is reduced.

[0149] The posture estimation method according to the embodiment is a posture estimation method for estimating at least its own posture based on detection information from an IMU, and includes a calculation for identifying the direction of a radiation source based on radiation detection results from a plurality of pixels in a radiation detection unit in which a plurality of pixels for detecting radiation are discretely arranged in three dimensions, and an attitude estimation direction in which an error occurring in the detection information from the IMU is corrected based on the information on the direction of the radiation source identified by the calculation. This posture estimation method can also achieve the same functions and effects as the posture estimation device according to the embodiment described above.

[0150] The imaging device (camera 51) according to an embodiment includes an imaging unit that obtains an image using an imaging element, a radiation detection unit having a plurality of radiation-detecting pixels three-dimensionally arranged discretely, and a radiation source direction detection unit that performs calculations to identify the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit, a posture estimation unit that estimates at least its own posture based on IMU detection information, a correction unit that corrects errors in the IMU detection information based on the radiation source direction information detected by the radiation source direction detection unit, and a blur correction unit (41) that performs blur correction processing on the captured image based on posture information estimated by the posture estimation unit based on the IMU detection information corrected by the correction unit. This realizes an imaging device that can perform blur correction processing based on IMU detection information with appropriately corrected errors. Therefore, an imaging device with improved blur correction accuracy can be realized.

[0151] The mobile body according to the embodiment includes a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit, an attitude estimation unit that estimates at least its own attitude based on detection information from an IMU, a correction unit that corrects errors that occur in the detection information from the IMU based on the information on the direction of the radiation source detected by the radiation source direction detection unit, and an attitude control unit (same as above 53) that performs attitude control processing based on the attitude information estimated by the attitude estimation unit based on the detection information from the IMU after correction by the correction unit. This makes it possible to realize a mobile body that can perform attitude control with high precision.

[0152] An analysis device according to an embodiment includes a radiation detection unit having a plurality of pixels that detect radiation discretely arranged in three dimensions, a radiation source direction detection unit having a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit, a posture estimation unit that estimates at least its own posture based on detection information from an IMU, a correction unit that corrects errors that occur in the detection information from the IMU based on the information on the direction of the radiation source detected by the radiation source direction detection unit, and a motion analysis unit (same as 40) that performs motion analysis processing on its own posture based on the information on the posture estimated by the posture estimation unit based on the detection information from the IMU after correction by the correction unit. This makes it possible to realize an analysis device that can perform highly accurate motion analysis.

[0153] An information processing device (server device 55) according to an embodiment includes a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to determine the direction of the radiation source based on the radiation detection results of the plurality of pixels in the radiation detection unit, a receiving unit (F1) that receives information on the direction of the radiation source identified from the detection results of the radiation source direction detection unit from a plurality of terminal devices located at different positions on the Earth, and a radiation source position calculation unit (F2) that performs calculations to determine the position of the radiation source based on the radiation source direction information received by the receiving unit from the plurality of terminal devices and position information of the plurality of terminal devices. This makes it possible to realize an information processing device that is capable of determining the position of a target radiation source with high accuracy.

[0154] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0155] <7. The Present Technology> The present technology may also have the following configurations. (1) A radiation source direction detecting device comprising: a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results from the plurality of pixels in the radiation detection unit. (2) The radiation source direction detecting device described in (1), in which the pixels are configured to include radiation / light conversion units that emit light in response to the radiation, and photoelectric conversion elements that detect the light emitted by the radiation / light conversion units. (3) The radiation source direction detecting device described in (2), in which SPAD elements are used as the photoelectric conversion elements. (4) The radiation source direction detecting device described in (2) or (3), in which the radiation / light conversion units are scintillators. (5) The radiation source direction detecting device according to any one of (1) to (4), wherein the radiation detection unit has a spherical portion or a polyhedron portion, and the pixels are arranged on a surface of the spherical portion or on each surface of the polyhedron portion. (6) The radiation source direction detecting device according to any one of (1) to (5), wherein the calculation unit, in response to detection of the radiation by a certain pixel, acquires the radiation detection result for a pixel opposite to the trigger pixel that detected the radiation within a predetermined window period after the radiation detection by the trigger pixel, and, if it determines based on the radiation detection result that the detected intensity of the radiation for the pixel opposite to the trigger pixel within the window period was not equal to or greater than a threshold, does not identify the direction of the radiation source based on the radiation detection result. (7) The radiation source direction detecting device according to any one of (1) to (6), further comprising a sensitivity control unit that controls the radiation detection sensitivity of the pixel based on time information.(9) The radiation source direction detecting device according to any one of (1) to (8), wherein the radiation detection unit is formed into a three-dimensional structure by bending a flexible substrate on which a plurality of the pixels are mounted. (10) The radiation source direction detecting device according to any one of (1) to (8), wherein the pixels in the radiation detection unit are formed on a base material by transfer technology. (11) The radiation source direction detecting device according to (4), wherein a current-carrying circuit for actively controlling atomic arrangement is formed in the scintillator. (12) A radiation source direction detecting method, comprising: performing a calculation to identify the direction of the radiation source based on radiation detection results by a plurality of pixels in a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in a three-dimensional manner. (13) A posture estimation device comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit, a posture estimation unit that estimates at least its own posture based on detection information of an IMU, and a correction unit that corrects an error occurring in the detection information of the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit. (14) The posture estimation device according to (13), wherein the position of the radiation source is known, and comprises a reference radiation source direction acquisition unit that acquires the direction of the radiation source identified based on at least information on its own current position as a reference radiation source direction, and the correction unit corrects an error occurring in the detection information of the IMU based on the reference radiation source direction acquired by the reference radiation source direction acquisition unit and information on the direction of the radiation source detected by the radiation source direction detection unit. (15) The attitude estimation device according to any of (13) to (15), wherein the radiation source is the sun, the reference radiation source direction acquisition unit acquires a direction of the sun identified based on its own current position information and current time information as a reference sun direction, and the correction unit corrects an error occurring in the detection information of the IMU based on information on the reference sun direction acquired by the reference radiation source direction acquisition unit and the direction of the radiation source detected by the radiation source direction detection unit. (16) The attitude estimation device according to any of (13) to (15), wherein the correction unit performs the correction using any of a Kalman filter, a complementary filter, or a Madgwick filter.(17) The posture estimation device according to any of (13) to (16), wherein the correction unit calibrates correction parameters based on information about the direction of the radiation source detected by the radiation source direction detection unit, and continuously performs the correction during a period after the calibration. (18) The posture estimation device according to any of (13) to (17), further comprising a correction control unit that, when the number of times the radiation source direction detection unit detects the direction of the radiation source per unit time is less than a predetermined number, controls the correction unit to perform correction using a correction method different from the correction based on the information about the direction of the radiation source detected by the radiation source direction detection unit. (19) The posture estimation device according to any of (13) to (18), wherein a self-position is estimated based on detection information of the IMU corrected by the correction unit. (20) A posture estimation method for estimating at least its own posture based on detection information from an IMU, comprising: performing a calculation to identify a direction of a radiation source based on radiation detection results from a plurality of pixels in a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and correcting an error occurring in the detection information from the IMU based on the information on the direction of the radiation source identified by the calculation. (21) An imaging device comprising: an imaging unit that images a subject to obtain a captured image; a radiation source direction detection unit that has a radiation detection unit in which a plurality of pixels that detect radiation are three-dimensionally discretely arranged, and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; a correction unit that corrects an error occurring in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit; and a blur correction unit that performs blur correction processing on the captured image based on information on the posture estimated by the posture estimation unit based on the detection information of the IMU after correction by the correction unit.(22) A mobile body comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; a correction unit that corrects errors occurring in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit; and a posture control unit that performs posture control processing based on information on the posture estimated by the posture estimation unit based on the detection information from the IMU after correction by the correction unit. (23) An analysis device comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; a correction unit that corrects errors occurring in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit; and a motion analysis unit that performs motion analysis processing on the analysis device based on information on the posture estimated by the posture estimation unit based on the detection information from the IMU after correction by the correction unit. (24) An information processing device comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a receiving unit that receives information on the direction of the radiation source identified from the detection results of the radiation source direction detection unit from a plurality of terminal devices that are located at different positions on the Earth; and a radiation source position calculation unit that performs calculations to identify the position of the radiation source based on the information on the direction of the radiation source received by the receiving unit from the plurality of terminal devices and position information of the plurality of terminal devices.

[0156] DESCRIPTION OF SYMBOLS 1, 1D Radiation source direction detection unit 2 Radiation / light conversion section 3 Photoelectric conversion element 4 Semiconductor substrate 5 Reflection film 6 Organic protective film 7 Radiation / light conversion layer 8 Separate semiconductor substrate 9 Radiation detection unit Bs Flexible substrate FE Front end section Ba Conductor ball 10, 10A, 10B, 10C Radiation source direction detector 10a Spherical section 11 Radiation source direction calculation section Dr Radiation source direction PxT Trigger pixel PxO Opposite pixel Ap Opposite pixel area 15 Control section 16 Timekeeping section Dimu IMU estimated direction Dsd Detected radiation source direction Dsr Reference radiation source direction 20, 20A, 20B Position and orientation estimation device 21 Acceleration sensor 22 Angular velocity sensor 23 Orientation sensor 24 GNSS sensor 25, 25A, 25B Correction filter unit 26 Self-position and attitude estimation unit 27 Gravity and orientation true value calculation unit 28 Timer unit 29 Reference radiation source direction calculation unit 31 Delay compensation unit 32 Control unit DL Delay time 50 Smartphone 40 Motion analysis unit 51 Camera 41 Blur correction unit 52 Mobile body 53 Attitude control unit NT Network 55 Server device F1 Receiving unit F2 Radiation source position calculation unit

Claims

1. A radiation source direction detection device comprising: a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the results of radiation detection by the plurality of pixels in the radiation detection unit.

2. The radiation source direction detecting device according to claim 1, wherein the pixels are configured to have a radiation / light conversion section that emits light in response to the radiation, and a photoelectric conversion element that detects the light emitted by the radiation / light conversion section.

3. The radiation source direction detection device according to claim 2, wherein a SPAD element is used as the photoelectric conversion element.

4. The radiation source direction detecting device according to claim 2, wherein the radiation / light converting portion is a scintillator.

5. The radiation source direction detecting device according to claim 1, wherein the radiation detecting section has a spherical section or a polyhedral section, and the pixels are arranged on a surface of the spherical section or on each surface of the polyhedral section.

6. The radiation source direction detection device according to claim 1, wherein the calculation unit, in response to a certain pixel detecting the radiation, acquires a radiation detection result for an opposing pixel of the trigger pixel that detected the radiation within a predetermined window period after the radiation detection by the trigger pixel, and if it determines based on the radiation detection result that the detection intensity of the radiation within the window period of the opposing pixel was not equal to or greater than a threshold, does not identify the direction of the radiation source based on the radiation detection result.

7. The radiation source direction detection device according to claim 6, wherein the calculation unit obtains the radiation detection result within the window period for each pixel in an opposing pixel area including the opposing pixel of the trigger pixel and a plurality of surrounding pixels, identifies a pixel among the pixels in the opposing pixel area that had the maximum radiation detection intensity within the window period, and determines the direction from the identified pixel through the trigger pixel as the direction of the radiation source.

8. The radiation source direction detection device according to claim 1, further comprising a sensitivity control section for controlling the detection sensitivity of said radiation in said pixels based on time information.

9. The radiation source direction detecting device according to claim 1, wherein the radiation detecting section is formed into a three-dimensional structure by bending a flexible substrate on which a plurality of the pixels are mounted.

10. The radiation source direction detector according to claim 1, wherein the pixels in the radiation detection section are formed on a base material by a transfer technique.

11. The radiation source direction detecting device according to claim 4, wherein the scintillator is provided with a current-carrying circuit for actively controlling the atomic arrangement.

12. A radiation source direction detection method comprising the steps of: performing a calculation to identify the direction of the radiation source based on the results of radiation detection by a plurality of pixels in a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in a three-dimensional space.

13. A posture estimation device comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; and a correction unit that corrects errors occurring in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit.

14. An attitude estimation device as described in claim 13, wherein the position of the radiation source is known, and the device is equipped with a reference radiation source direction acquisition unit that acquires the direction of the radiation source identified based on at least its own current position information as a reference radiation source direction, and the correction unit corrects errors that occur in the detection information of the IMU based on information on the reference radiation source direction acquired by the reference radiation source direction acquisition unit and the direction of the radiation source detected by the radiation source direction detection unit.

15. The attitude estimation device of claim 14, wherein the radiation source is the sun, the reference radiation source direction acquisition unit acquires the direction of the sun identified based on its own current position information and current time information as a reference sun direction, and the correction unit corrects errors occurring in the detection information of the IMU based on information on the reference sun direction acquired by the reference radiation source direction acquisition unit and the direction of the radiation source detected by the radiation source direction detection unit.

16. The posture estimation device according to claim 13, wherein the correction unit performs the correction using any one of a Kalman filter, a complementary filter, and a Madgwick filter.

17. The posture estimation device according to claim 13, wherein the correction unit calibrates correction parameters based on information about the direction of the radiation source detected by the radiation source direction detection unit, and continuously performs the correction during a period after the calibration.

18. A posture estimation device as described in claim 13, further comprising a correction control unit that, when the number of times the radiation source direction detection unit detects the direction of the radiation source per unit time does not reach a predetermined number, controls the correction unit to execute a correction using a correction method different from the correction based on information on the direction of the radiation source detected by the radiation source direction detection unit.

19. The posture estimation device according to claim 13, further comprising: a position estimation unit that estimates a position of the posture estimation device based on the detection information of the IMU that has been corrected by the correction unit.

20. A posture estimation method for estimating at least its own posture based on detection information from an IMU, comprising: performing a calculation to identify a direction of a source of the radiation based on radiation detection results by a plurality of pixels in a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and correcting errors occurring in the detection information from the IMU based on the information on the direction of the radiation source identified by the calculation.

21. An imaging device comprising: an imaging unit that images a subject to obtain an image; a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions, and a calculation unit that performs calculations to identify the direction of the radiation source based on a result of the radiation detection by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; a correction unit that corrects errors occurring in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit; and a blur correction unit that performs blur correction processing on the captured image based on the posture information estimated by the posture estimation unit based on the detection information of the IMU after correction by the correction unit.

22. A mobile body comprising: a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a radiation source direction detection unit having a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; a correction unit that corrects errors that occur in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit; and a posture control unit that performs posture control processing based on the posture information estimated by the posture estimation unit based on the detection information from the IMU after correction by the correction unit.

23. An analysis device comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the radiation detection results by the plurality of pixels in the radiation detection unit; a posture estimation unit that estimates at least its own posture based on detection information from an IMU; a correction unit that corrects errors occurring in the detection information from the IMU based on information on the direction of the radiation source detected by the radiation source direction detection unit; and a motion analysis unit that performs motion analysis processing on the device itself based on the posture information estimated by the posture estimation unit based on the detection information from the IMU after correction by the correction unit.

24. An information processing device comprising: a radiation source direction detection unit having a radiation detection unit in which a plurality of pixels that detect radiation are discretely arranged in three dimensions; and a calculation unit that performs calculations to identify the direction of the radiation source based on the results of radiation detection by the plurality of pixels in the radiation detection unit, the information processing device comprising: a receiving unit that receives information on the direction of the radiation source identified from the detection results of the radiation source direction detection unit from a plurality of terminal devices arranged at different positions on the Earth; and a radiation source position calculation unit that performs calculations to identify the position of the radiation source based on the information on the direction of the radiation source received by the receiving unit from the plurality of terminal devices and position information of the plurality of terminal devices.

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