Method and apparatus for acquiring 3D information

Abstract

To provide a three-dimensional information acquisition method with which it is possible to acquire three-dimensional information in the inside of a substance that interacts with light.SOLUTION: A three-dimensional information acquisition method comprises: a light irradiation step in which a glass cell GC where cesium is filled in is irradiated from two directions with first irradiation light L1 and second irradiation light L2 having a first coded pattern PT1 and a second coded pattern PT2 in which a bright pixel bpx and a dark pixel dpx are arranged; a light reception step in which the first irradiation light L1 and second irradiation light L2 having passed through the glass cell GC are received; and an acquisition step in which three-dimensional information in the inside of the glass cell GC is acquired using the first coded pattern PT1 of the first irradiation light L1 and the second coded pattern PT2 of the second irradiation light L2, and the light signals of the first irradiation light L1 and second irradiation light L2 received in the light reception step. The light irradiation step and the acquisition step are executed a number of times using multiple rays of irradiation light having different coded patterns.SELECTED DRAWING: Figure 1

Description

Technical Field

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[0001] The present invention relates to a three-dimensional information acquisition method and a three-dimensional information acquisition device.

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, a cell containing an alkali metal atom group, a pump light optical system for irradiating the cell with pump light, a first probe light optical system for irradiating the cell with first probe light so as to intersect the pump light in the cell, a second probe light optical system for irradiating the cell with second probe light so as to intersect the pump light and the first probe light in the cell, a first detector for detecting the rotation angle of the polarization plane of the first probe light that has passed through the cell, a second detector for detecting the rotation angle of the polarization plane of the second probe light that has passed through the cell, a magnetic field applying means for applying a static magnetic field to the cell, and a calculating means for calculating information on magnetic field strengths in two different directions in the cell from the rotation angle detected by the first detector and the rotation angle detected by the second detector are known as an optical pumping magnetometer.

[0003] In such a magnetometer, it is possible to obtain information on magnetic field strengths in two different directions in a substance such as an alkali metal atom group that interacts with light contained in the cell, that is, two-dimensional information on the magnetic field strength in the substance contained in the cell.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the optical pumping magnetometer having the configuration disclosed in Patent Document 1, it is possible to obtain information on magnetic field strengths in two different directions in the cell, that is, two-dimensional information on the magnetic field strength in the substance contained in the cell, but it has been difficult to obtain three-dimensional information in the substance.

[0006] This invention has been made in view of the above circumstances, and provides a three-dimensional information acquisition method and a three-dimensional information acquisition apparatus that can acquire three-dimensional information inside a material that interacts with light. [Means for solving the problem]

[0007] In other words, the 3D information acquisition method comprises: a light irradiation step in which irradiation light having an encoded pattern in which bright pixels, which are regions where light is irradiated, and dark pixels, which are regions where light is not irradiated, are arranged, is irradiated from two directions onto a material that interacts with the irradiation light; a light receiving step in which the irradiation light irradiated onto the material in the light irradiation step and transmitted through the material is received; and an acquisition step in which 3D information inside the material is acquired using the encoded pattern of the irradiation light irradiated onto the material in the light irradiation step and the optical signal of the irradiation light received in the light receiving step. The light irradiation step and the acquisition step are performed multiple times using multiple irradiation lights having different encoded patterns, and in the acquisition step, the 3D information is acquired using the multiple encoded patterns and multiple optical signals from the multiple light irradiation steps and acquisition steps performed multiple times.

[0008] This makes it possible to acquire three-dimensional information within a material with high precision.

[0009] Furthermore, in the light irradiation step, the irradiation light is irradiated onto the substance from two orthogonal directions.

[0010] This makes it possible to clearly demarcate sensitive and insensitive regions within a substance.

[0011] Furthermore, the substance has a plurality of partitioned cells that are demarcated by the coding pattern of the irradiation light irradiated from two directions, and the light irradiation step and the light receiving step are performed a number of times greater than or equal to the number of partitioned cells in the substance.

[0012] This makes it possible to acquire three-dimensional information within a material with high precision.

[0013] Furthermore, the optical signal changes depending on the magnitude of the magnetic field applied to the material, and the three-dimensional information is the three-dimensional magnetic field distribution inside the material.

[0014] In this way, by obtaining the three-dimensional magnetic field distribution within a material, the location of the magnetic field source can be estimated with high accuracy.

[0015] Furthermore, the substance is an alkali metal, and the irradiated light is laser light having a resonant wavelength for alkali metals and also having a circularly polarized component.

[0016] This makes it possible to obtain three-dimensional magnetic field distribution as three-dimensional information within a material.

[0017] Furthermore, the 3D information acquisition device includes a light source that emits light, a material that interacts with the light, a first optical system that assigns a first coding pattern to the light emitted from the light source, in which bright pixels are regions that are illuminated by light and dark pixels are regions that are not illuminated by light, and irradiates the material with the first illumination light to which the first coding pattern has been assigned, a second optical system that assigns a second coding pattern to the light emitted from the light source, in which bright pixels are regions that are illuminated by light and dark pixels are regions that are not illuminated by light, and irradiates the material with the second illumination light to which the second coding pattern has been assigned, from a direction different from the irradiation direction of the first illumination light, and the first illumination light that has been transmitted through the material The device comprises a first photodetector that receives incoming light, a second photodetector that receives the second irradiation light transmitted through the material, and a controller that acquires three-dimensional information inside the material using the first coding pattern, the second coding pattern, the optical signal of the first irradiation light received by the first photodetector, and the optical signal of the second irradiation light received by the second photodetector, wherein the controller acquires three-dimensional information inside the material using a plurality of different first coding patterns, a plurality of different second coding patterns, a plurality of optical signals of the first irradiation light corresponding to the plurality of different first coding patterns, and a plurality of optical signals of the second irradiation light corresponding to the plurality of different second coding patterns.

[0018] This makes it possible to acquire three-dimensional information within a material with high precision. [Effects of the Invention]

[0019] According to the present invention, three-dimensional information within a material can be acquired with high precision. [Brief explanation of the drawing]

[0020] [Figure 1] This is a schematic diagram showing a 3D information acquisition device. [Figure 2] This is a diagram showing the first mirror array device. [Figure 3]It is a perspective view showing a state where a first irradiation light having a first encoding pattern and a second irradiation light having a second encoding pattern are irradiated onto a glass cell. [Figure 4] It is an exploded perspective view showing a partition cell in the glass cell irradiated with the first irradiation light and the second irradiation light. [Figure 5] It is a diagram showing a pattern of a sensitive region and an insensitive region in the upper partition cell when the glass cell is irradiated with the first irradiation light and the second irradiation light. [Figure 6] It is an exploded perspective view showing a partition cell in a glass cell irradiated with a first irradiation light and a second irradiation light having a first encoding pattern and a second encoding pattern different from the first irradiation light and the second irradiation light irradiated onto the glass cell shown in FIG. 4.

Embodiments for Carrying out the Invention

[0021] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

[0022] [Outline of 3D Information Acquisition Method] The 3D information acquisition method according to the present invention includes a light irradiation step of irradiating an irradiation light having an encoding pattern in which bright pixels, which are regions irradiated with light, and dark pixels, which are regions not irradiated with light, are arranged, onto a substance that interacts with the irradiation light from two directions, a light reception step of receiving the irradiation light that has been irradiated onto the substance and transmitted through the substance in the light irradiation step, and an acquisition step of acquiring 3D information inside the substance using the encoding pattern of the irradiation light irradiated onto the substance in the light irradiation step and the optical signal of the irradiation light received in the light reception step. The light irradiation step and the acquisition step are executed a plurality of times using a plurality of irradiation lights having different encoding patterns, and in the acquisition step, the 3D information is acquired using the plurality of encoding patterns and the plurality of optical signals in the plurality of light irradiation steps and the acquisition steps executed a plurality of times.

[0023] In this case, alkali metals such as cesium, potassium, and rubidium can be used as the substance that interacts with the irradiated light. Furthermore, light having a circularly polarized component can be used as the irradiated light that interacts with the substance.

[0024] Light with circularly polarized components is used to align the spin orientation of unpaired electrons in atoms that make up a substance. Atoms in a substance irradiated with light with circularly polarized components become spin-polarized and magnetized according to the polarization direction of the irradiated light. Alkali metals, as substances that interact with irradiated light, become spin-polarized by interacting with light with circularly polarized components.

[0025] Light that causes the spin polarization of atoms that make up a substance is called "pump light." The process of causing the spin polarization of atoms that make up a substance using pump light is called "optical pumping."

[0026] The pump light preferably consists only of circularly polarized light, but is not limited to this; it may also contain other polarization components as long as it has a circularly polarized component. Furthermore, the pump light used is light with a wavelength that causes the alkali metal to undergo an optical transition from the ground state to the excited state.

[0027] The spin polarization of a material, generated by optical pumping, precesses at a Larmor frequency determined by the magnitude of the static magnetic field when a static magnetic field is applied.

[0028] When an alternating magnetic field is applied to a material that is already subjected to a static magnetic field, the phase of the material's precession is aligned by the applied alternating magnetic field. The light transmitted through the material is then modulated in intensity according to the magnetic field and emitted from the material. Alkali metals that make up the material have the property that, when a magnetic field is applied, the light transmittance changes according to the intensity of the magnetic field.

[0029] In the method for acquiring three-dimensional information, it is possible to acquire, for example, the three-dimensional distribution of the magnetic field inside a material as three-dimensional information within the material.

[0030] [3D information acquisition device] Next, we will describe the 3D information acquisition device used when performing the 3D information acquisition method.

[0031] The 3D information acquisition device 1 shown in Figure 1 comprises a glass cell GC, a light source 11, a polarizing beam splitter 12, a first mirror array device 13, a second mirror array device 14, a first photodetector 15, a second photodetector 16, a controller 20, a 3D Helmholtz coil HC, and a metal wire W.

[0032] A glass cell GC is a sealed, cubic container made of glass, containing cesium, an alkali metal, in gaseous form. For example, a 30mm cube glass cell can be used as a glass cell GC. Cesium is an example of a substance that interacts with irradiated light. In addition to cesium, buffer gases such as nitrogen and helium can be sealed inside the glass cell GC. By adjusting the amount of buffer gas sealed inside the glass cell GC, the detection sensitivity and sensitivity bandwidth of the glass cell GC can be optimized.

[0033] In the 3D information acquisition device 1, a 3D Helmholtz coil HC is arranged to surround the glass cell GC, and a static magnetic field is applied to the glass cell GC by the 3D Helmholtz coil HC.

[0034] The metal wire W is positioned in close proximity to the glass cell GC. An alternating current flows through the metal wire W, and an alternating magnetic field is generated from the metal wire W. The alternating magnetic field generated from the metal wire W is applied inside the glass cell GC. The magnitude of the alternating magnetic field from the metal wire W applied inside the glass cell GC varies depending on the distance from the metal wire W. The frequency of the alternating magnetic field generated from the metal wire W can be set to, for example, 70 kHz.

[0035] The light source 11 emits laser light that is irradiated onto the glass cell GC. Laser light is an example of the light emitted by the light source. For example, an externally reclined laser (ECDL) can be used as the light source 11. For example, the light source 11 can be one that can produce a laser light output of 100 mW. The laser light is emitted from the optical fiber 11a of the light source 11. The wavelength of the laser light emitted from the light source 11 is adjusted to 852 nm, which is the resonance wavelength of cesium.

[0036] The laser light emitted from the light source 11 is incident on the polarizing beam splitter 12. The polarizing beam splitter 12 splits the laser light emitted from the light source 11 into two beams of equal intensity. One of the laser beams split by the polarizing beam splitter 12 is incident on the first mirror array device 13, and the other laser beam split by the polarizing beam splitter 12 is incident on the second mirror array device 14.

[0037] A half-wave plate 31 is placed between the light source 11 and the polarizing beam splitter 12. The laser light emitted from the light source 11 passes through the half-wave plate 31 before being incident on the polarizing beam splitter 12. The laser light emitted from the light source 11 can have its intensity adjusted as needed by the aperture and is reflected by a mirror before being incident on the polarizing beam splitter 12.

[0038] A quarter-wave plate 32 is placed between the polarizing beam splitter 12 and the first mirror array device 13, and a quarter-wave plate 33 is placed between the polarizing beam splitter 12 and the second mirror array device 14.

[0039] The laser light emitted from the polarizing beam splitter 12 passes through the quarter-wave plate 32 before being incident on the first mirror array device 13. The laser light emitted from the polarizing beam splitter 12 becomes circularly polarized after passing through the quarter-wave plate 32.

[0040] The laser light emitted from the polarizing beam splitter 12 passes through the quarter-wave plate 33 before being incident on the second mirror array device 14. The laser light emitted from the polarizing beam splitter 12 becomes circularly polarized after passing through the quarter-wave plate 33.

[0041] The first mirror array device 13 is a reflective member that reflects laser light incident on the first mirror array device 13 and irradiates the glass cell GC with it. When the laser light incident on the first mirror array device 13 is reflected, a first coding pattern PT1 is added to the laser light. The first coding pattern PT1 is a pattern in which bright pixels bpx, which are regions illuminated by light, and dark pixels dpx, which are regions not illuminated by light, are arranged. The first coding pattern PT1 is an example of a coding pattern.

[0042] As shown in Figure 2(a), the first mirror array device 13 is a device in which a large number of movable micromirrors 132 are arranged on a substrate 131. The large number of micromirrors 132 are arranged, for example, in a grid pattern in the matrix direction.

[0043] The micromirror 132 is capable of reflecting laser light incident on the first mirror array device 13 and can move between an on-position (position of micromirror 132a in Figure 2(a)) and an off-position (position of micromirror 132b in Figure 2(a)) with different tilt directions. The micromirror 132 can be driven by the controller 20 to switch between the on-position and the off-position.

[0044] Laser light reflected by the micromirror 132 in the ON position is directed onto the glass cell GC, while laser light reflected by the micromirror 132 in the OFF position is not directed onto the glass cell GC.

[0045] Therefore, by individually driving each micromirror 132 to an ON or OFF position, a first coding pattern PT1 can be assigned to the laser light reflected by the first mirror array device 13, which is arranged with bright pixels bpx, which are areas illuminated by light, and dark pixels dpx, which are areas not illuminated by light.

[0046] As shown in Figure 2(b), in the first coding pattern PT1, multiple pixels px are arranged in a grid, and each pixel px is either a bright pixel bpx, which is an area illuminated by light, or a dark pixel dpx, which is an area not illuminated by light. Each pixel px in the first coding pattern PT1 is formed in a rectangular shape. In the first coding pattern PT1 shown in Figure 2(b), there are 5 rows of pixels px in the row direction and 5 columns of pixels px in the column direction.

[0047] Bright pixels bpx of the first coding pattern PT1 are formed when laser light incident on the first mirror array device 13 is reflected by the on-position micromirror 132a, and dark pixels dpx are formed when laser light incident on the first mirror array device 13 is reflected by the off-position micromirror 132b.

[0048] The second mirror array device 14 is a reflective member that reflects the laser light incident on the second mirror array device 14 and irradiates the glass cell GC with it. The second mirror array device 14 is configured in the same way as the first mirror array device 13, and when it reflects the laser light incident on the second mirror array device 14, it imparts a second coding pattern PT2 to the laser light.

[0049] The second coding pattern PT2 is a pattern in which bright pixels (bpx), which are areas illuminated by light, and dark pixels (dpx), which are areas not illuminated by light, are arranged, and is constructed in the same way as the first coding pattern PT1. The second coding pattern PT2 is an example of a coding pattern.

[0050] The second mirror array device 14 includes a substrate 141 and micromirrors 142 that correspond to the substrate 131 and micromirrors 132 of the first mirror array device 13.

[0051] In the second coding pattern PT2, multiple pixels px are arranged in a grid, and each pixel px is either a bright pixel bpx, which is an area illuminated by light, or a dark pixel dpx, which is an area not illuminated by light. Each pixel px in the second coding pattern PT2 is formed in a rectangular shape.

[0052] Bright pixels bpx of the second coding pattern PT2 are formed when laser light incident on the second mirror array device 14 is reflected by the on-position micromirror 142a, while dark pixels dpx are formed when laser light incident on the second mirror array device 14 is reflected by the off-position micromirror 142b.

[0053] The laser light reflected by the first mirror array device 13 and imbued with the first coding pattern PT1 is irradiated onto the glass cell GC as the first irradiation light L1. The laser light reflected by the second mirror array device 14 and imbued with the second coding pattern PT2 is irradiated onto the glass cell GC as the second irradiation light L2.

[0054] In the 3D information acquisition device 1, a polarizing beam splitter 12, a first mirror array device 13, a half-wave plate 31, a quarter-wave plate 32, and lenses, etc., are used to apply a first coding pattern PT1 to the laser light emitted from the light source 11, and a first illumination light L1 to which the first coding pattern PT1 has been applied is irradiated onto the glass cell GC, forming a first optical system OS1.

[0055] Furthermore, in the 3D information acquisition device 1, a polarizing beam splitter 12, a second mirror array device 14, a half-wave plate 31, a quarter-wave plate 33, and lenses, etc., are used to apply a second coding pattern PT2 to the laser light emitted from the light source 11, and a second illumination light L2 to which the second coding pattern PT2 has been applied is irradiated onto the glass cell GC, forming a second optical system OS2.

[0056] As shown in Figures 1 and 3, the irradiation direction of the first irradiation light L1 to the glass cell GC and the irradiation direction of the second irradiation light L2 to the glass cell GC are orthogonal. In this embodiment, the irradiation direction of the first irradiation light L1 is defined as the X direction, and the irradiation direction of the second irradiation light L2 is defined as the Y direction, which is orthogonal to the X direction. Furthermore, the direction that is orthogonal to the X and Y directions and goes from top to bottom in Figure 3 is defined as the Z direction.

[0057] The first irradiation light L1 and the second irradiation light L2 are simultaneously irradiated onto the glass cell GC. The first irradiation light L1, upon irradiating the glass cell GC, passes through the glass cell GC, which becomes the space for acquiring three-dimensional information, while retaining the first encoding pattern PT1. Similarly, the second irradiation light L2, upon irradiating the glass cell GC, passes through the glass cell GC, which becomes the space for acquiring three-dimensional information, while retaining the second encoding pattern PT2.

[0058] The first coding pattern PT1 and the second coding pattern PT2 shown in Figure 3 each have 3 rows and 3 columns of pixels px. In this case, the rows of the first coding pattern PT1 are aligned along the Y direction and the columns are aligned along the Z direction. The rows of the second coding pattern PT2 are aligned along the X direction and the columns are aligned along the Z direction.

[0059] For the first encoding pattern PT1, the pixels px in the upper row are defined as pixels px011, px021, and px031, moving from upstream to downstream in the Y direction; the pixels px in the middle row are defined as pixels px012, px022, and px032, moving from upstream to downstream in the Y direction; and the pixels px in the lower row are defined as pixels px013, px023, and px033, moving from upstream to downstream in the Y direction.

[0060] In the first encoding pattern PT1 shown in Figure 3, pixels px011, px013, px022, px023, and px031 are set to bright pixels (bpx), while pixels px012, px021, px032, and px033 are set to dark pixels (dpx).

[0061] For the second coding pattern PT2, the pixels px in the upper row are defined as pixels px101, px201, and px301, moving from upstream to downstream in the X direction; the pixels px in the middle row are defined as pixels px102, px202, and px302, moving from upstream to downstream in the X direction; and the pixels px in the lower row are defined as pixels px103, px203, and px303, moving from upstream to downstream in the X direction.

[0062] In the second coding pattern PT2 shown in Figure 3, pixels px102, px201, px202, and px303 are set to bright pixels (bpx), while pixels px101, px103, px203, px301, and px302 are set to dark pixels (dpx).

[0063] As shown in Figure 4, within the glass cell GC, partition cells sc can be defined corresponding to each pixel px of the first coding pattern PT1 and the second coding pattern PT2. Specifically, a total of 27 partition cells sc are defined by the intersection of the first coding pattern PT1, which has 3 rows and 3 columns of pixels px, and the second coding pattern PT2, which also has 3 rows and 3 columns of pixels px. In this case, the rows of the partition cells sc are aligned along the X direction, the columns are aligned along the Y direction, and the layers are aligned along the Z direction.

[0064] For each partition cell sc, the partition cells sc in the row located in the upper Z-direction and upstream Y-direction are defined as partition cells sc111, sc211, and sc311, moving from upstream to downstream in the X-direction; the partition cells sc in the row located in the upper Z-direction and midstream Y-direction are defined as partition cells sc121, sc221, and sc321, moving from upstream to downstream in the X-direction; and the partition cells sc in the row located in the upper Z-direction and downstream Y-direction are defined as partition cells sc131, sc231, and sc331, moving from upstream to downstream in the X-direction.

[0065] Furthermore, regarding partition cells sc, the partition cells sc in rows located in the middle layer in the Z direction and upstream in the Y direction are defined as partition cells sc112, sc212, and sc312, moving from upstream to downstream in the X direction; the partition cells sc in rows located in the middle layer in the Z direction and midstream in the Y direction are defined as partition cells sc122, sc222, and sc322, moving from upstream to downstream in the X direction; and the partition cells sc in rows located in the middle layer in the Z direction and downstream in the Y direction are defined as partition cells sc132, sc232, and sc332, moving from upstream to downstream in the X direction.

[0066] Furthermore, for each partition cell sc, the partition cells sc in rows located in the lower Z-direction and upstream Y-direction are defined as partition cells sc113, sc213, and sc313, moving from upstream to downstream in the X-direction; the partition cells sc in rows located in the lower Z-direction and midstream Y-direction are defined as partition cells sc123, sc223, and sc323, moving from upstream to downstream in the X-direction; and the partition cells sc in rows located in the lower Z-direction and downstream Y-direction are defined as partition cells sc133, sc233, and sc333, moving from upstream to downstream in the X-direction.

[0067] In the region corresponding to the bright pixels bpx of the first coding pattern PT1 within the glass cell GC irradiated with the first irradiation light L1, the cesium sealed within the glass cell GC becomes spin-polarized, forming a sensitive region Sa that is sensitive to the magnetic field. On the other hand, in the region corresponding to the dark pixels dpx of the first coding pattern PT1 within the glass cell GC irradiated with the first irradiation light L1, the cesium within the glass cell GC does not become spin-polarized, forming an insensitive region Da that is not sensitive to the magnetic field.

[0068] Furthermore, in the region corresponding to the bright pixels bpx of the second coding pattern PT2 within the glass cell GC irradiated with the second irradiation light L2, the cesium sealed within the glass cell GC becomes spin-polarized, becoming a sensitive region Sa that is sensitive to the magnetic field. On the other hand, in the region corresponding to the dark pixels dpx of the second coding pattern PT2 within the glass cell GC irradiated with the second irradiation light L2, the cesium within the glass cell GC does not become spin-polarized, becoming an insensitive region Da that is not sensitive to the magnetic field.

[0069] However, in the glass cell GC irradiated with the first irradiation light L1 and the second irradiation light L2, in the region where the region corresponding to the bright pixels bpx of the first coding pattern PT1 and the region corresponding to the bright pixels bpx of the second coding pattern PT2 intersect, cesium cannot be spin-polarized in orthogonal directions by the respective light from the first irradiation light L1 and the second irradiation light L2. Therefore, this region becomes an insensitive region Da that is not sensitive to the magnetic field, similar to the region through which neither the first irradiation light L1 nor the second irradiation light L2 passes.

[0070] In other words, within the glass cell GC, the region through which either the first irradiation light L1 or the second irradiation light L2 passes becomes the sensitive region Sa, and the region through which neither the first irradiation light L1 nor the second irradiation light L2 passes, as well as the region through which both the first irradiation light L1 and the second irradiation light L2 pass, becomes the insensitive region Da.

[0071] As shown in Figure 5, for example, in the first coding pattern PT1 of the first illumination light L1 reflected by the first mirror array device 13, if we represent pixels px corresponding to bright pixels bpx that are illuminated by light as "1" and pixels px corresponding to dark pixels dpx that are not illuminated by light as "0", then in the upper row, pixels px011 and px031, which are bright pixels bpx, are represented as "1", and pixel px021, which is a dark pixel dpx, is represented as "0".

[0072] In the second coding pattern PT2 of the second illumination light L2 reflected by the second mirror array device 14, if we represent pixels px corresponding to bright pixels bpx that are illuminated by light as "-1" and pixels px corresponding to dark pixels dpx that are not illuminated by light as "0", then in the upper row, pixel px201, which is a bright pixel bpx, is represented as "1", and pixels px101 and px301, which are dark pixels, are represented as "0".

[0073] Furthermore, regarding the partition cells sc within the glass cell GC, if we represent the partition cells sc in the sensitive region Sa as "1" or "-1" and the partition cells sc in the insensitive region Da as "0", then the upper partition cells sc111 to sc331 in the glass cell GC are represented as shown in Figure 5.

[0074] In other words, the partition cell sc111 where the light pixel bpx pixel px011 and the dark pixel dpx pixel px101 intersect, the partition cell sc131 where the light pixel bpx pixel px031 and the dark pixel dpx pixel px101 intersect, the partition cell sc221 where the dark pixel dpx pixel px021 and the light pixel bpx pixel px201 intersect, the partition cell sc311 where the light pixel bpx pixel px011 and the dark pixel dpx pixel px301 intersect, and the partition cell sc331 where the light pixel bpx pixel px031 and the dark pixel dpx pixel px301 intersect are spin-polarized and become the sensitive region Sa, which is represented as "1" or "-1".

[0075] On the other hand, the partition cell sc121 where the dark pixel px021 and the dark pixel px101 intersect, the partition cell sc211 where the bright pixel px011 and the bright pixel px201 intersect, the partition cell sc231 where the bright pixel px031 and the bright pixel px201 intersect, and the partition cell sc321 where the dark pixel px021 and the dark pixel px301 intersect are in a dead region Da without spin polarization and are represented as "0".

[0076] Furthermore, in the glass cell GC, the middle layer partition cells sc112~sc332 and the lower layer partition cells sc113~sc333 are spin-polarized and become the sensitive region Sa.

[0077] On the other hand, partition cells sc122, sc222, sc312, sc332, sc133, sc233, sc313, and sc323 become inactive regions Da without spin polarization.

[0078] The first illumination light L1 transmitted through the glass cell GC is received by the first photodetector 15, and the second illumination light L2 transmitted through the glass cell GC is received by the second photodetector 16. The first photodetector 15 receives the first illumination light L1 transmitted through the glass cell GC as a whole, and the second photodetector 16 receives the second illumination light L2 transmitted through the glass cell GC as a whole. The first photodetector 15 is an example of a first photodetector, and the second photodetector 16 is an example of a second photodetector.

[0079] The controller 20 comprises a personal computer 21, a first lock-in amplifier 22, a second lock-in amplifier 23, and a signal generator 24. The first lock-in amplifier 22 is connected to the first photodetector 15, and the second lock-in amplifier 23 is connected to the second photodetector 16. The personal computer 21 is connected to the light source 11, the first mirror array device 13, the second mirror array device 14, the first lock-in amplifier 22, and the second lock-in amplifier 23. The signal generator 24 is connected to the first lock-in amplifier 22 and the second lock-in amplifier 23. A three-dimensional Helmholtz coil HC and a metal wire W are connected to the signal generator 24.

[0080] The optical signal of the first illumination light L1 received by the first photodetector 15 is the optical signal acquired from the compartment cell sc that is in the sensitive region Sa of the first illumination light L1, and no optical signal is acquired from the compartment cell sc that is in the insensitive region Da. The intensity of the optical signal of the first illumination light L1 received by the first photodetector 15 is modulated by the alternating magnetic field applied inside the glass cell GC. The optical signal of the first illumination light L1 acquired by the first photodetector 15 is input to the first lock-in amplifier 22, and the amplitude of the modulated optical signal is measured by phase detection performed by the first lock-in amplifier 22.

[0081] The optical signal of the second illumination light L2 received by the second photodetector 16 is the optical signal acquired from the compartment cell sc that is in the sensitive region Sa of the second illumination light L2, and no optical signal is acquired from the compartment cell sc that is in the insensitive region Da. The intensity of the optical signal of the second illumination light L2 received by the second photodetector 16 is modulated by the alternating magnetic field applied inside the glass cell GC. The optical signal of the second illumination light L2 acquired by the second photodetector 16 is input to the second lock-in amplifier 23, and the amplitude of the modulated optical signal is measured by phase detection performed by the second lock-in amplifier 23. Reference signals are input to the first lock-in amplifier 22 and the second lock-in amplifier 23 from the signal generator 24.

[0082] In a compartment cell sc that is in the sensitive region Sa, the amplitude of the transmitted optical signal differs depending on the magnitude of the applied alternating magnetic field. The larger the alternating magnetic field applied to the compartment cell sc, the larger the amplitude of the optical signal transmitted through that compartment cell sc.

[0083] For example, in Figure 4, if the metal wire W is positioned along the X direction below (downstream in the Z direction) the partition cells sc113, sc213, and sc313, the magnetic field applied to partition cells sc112 and sc123, which are located further from the metal wire W than partition cell sc113, will be smaller than the magnetic field applied to partition cell sc113.

[0084] Therefore, the amplitude of the optical signal transmitted through compartment cells sc112 and sc123 is smaller than the amplitude of the optical signal transmitted through compartment cell sc113. Furthermore, the amplitude of the optical signal transmitted through compartment cell sc111, which is located further from the metal wire W than compartment cell sc112, is smaller than the amplitude of the optical signal transmitted through compartment cell sc112.

[0085] The optical signal of the first irradiation light L1 acquired by the first photodetector 15 is the sum of the optical signals corresponding to each compartment cell sc that is in the sensitive region Sa in the first irradiation light L1, and is expressed as the amplitude measured by the first lock-in amplifier 22. Therefore, the amplitude measured by the first lock-in amplifier 22 changes depending on the number of compartment cells sc that are in the sensitive region Sa included in the first irradiation light L1, and the magnitude of the alternating magnetic field applied to the compartment cells sc that are in the sensitive region Sa.

[0086] Similarly, the optical signal of the second irradiation light L2 acquired by the second photodetector 16 is the sum of the optical signals corresponding to each compartment cell sc that is in the sensitive region Sa in the second irradiation light L2, and is represented by the amplitude measured by the second lock-in amplifier 23. Therefore, the amplitude measured by the second lock-in amplifier 23 changes depending on the number of compartment cells sc that are in the sensitive region Sa included in the second irradiation light L2, and the magnitude of the alternating magnetic field applied to the compartment cells sc that are in the sensitive region Sa.

[0087] The amplitude measurements from the first lock-in amplifier 22 and the second lock-in amplifier 23 are input to the personal computer 21.

[0088] The personal computer 21 can control the driving of the micromirrors 132 in the first mirror array device 13 to switch the on and off positions of the micromirrors 132. This makes it possible to form multiple different first coding patterns PT1.

[0089] The personal computer 21 can control the driving of the micromirrors 142 in the second mirror array device 14 to switch between the on and off positions of the micromirrors 142. This makes it possible to form multiple different second coding patterns PT2.

[0090] In the 3D information acquisition device 1, a first irradiation light L1 having a different first coding pattern PT1 and a second irradiation light L2 having a different second coding pattern PT2 are irradiated onto a glass cell GC multiple times, and the optical signals of multiple first irradiation lights L1 are acquired by the first photodetector 15, while the optical signals of multiple second irradiation lights L2 are acquired by the second photodetector 16.

[0091] The first lock-in amplifier 22 measures the amplitude of the optical signal based on the acquired optical signals of the first illumination light L1, and the measured values ​​of the multiple amplitudes are input to the personal computer 21. The second lock-in amplifier 23 measures the amplitude of the optical signal based on the acquired optical signals of the second illumination light L2, and the measured values ​​of the multiple amplitudes are input to the personal computer 21.

[0092] The personal computer 21 can acquire the three-dimensional distribution of the alternating magnetic field, which is three-dimensional information inside the glass cell GC, using multiple different first coding patterns PT1, multiple different second coding patterns PT2, amplitude measurements based on multiple optical signals of first illumination light L1 corresponding to multiple different first coding patterns PT1, and amplitude measurements based on multiple optical signals of second illumination light L2 corresponding to multiple different second coding patterns PT2.

[0093] [Execution of 3D information acquisition method using 3D information acquisition device] When the 3D information acquisition method is executed using the 3D information acquisition device 1, the personal computer 21 first controls the emission of laser light from the light source 11. In this case, the laser light emitted from the light source 11 is adjusted to 852 nm, which is the resonance wavelength of the cesium sealed in the glass cell GC.

[0094] Next, the personal computer 21 controls the operation of the micromirrors 132 in the first mirror array device 13 to assign a first coding pattern PT1 to the laser light when it is reflected by the first mirror array device 13 after it has been emitted from the light source 11, passed through the half-wave plate 31 and the quarter-wave plate 32, and become circularly polarized.

[0095] Similarly, the personal computer 21 controls the operation of the micromirrors 142 in the second mirror array device 14 to impart a second coding pattern PT2 to the laser light emitted from the light source 11, which has passed through the half-wave plate 31 and the quarter-wave plate 33 and become circularly polarized, as it is reflected by the second mirror array device 14.

[0096] Laser light assigned the first coding pattern PT1 is irradiated into the glass cell GC as the first irradiation light L1 and penetrates the cesium in the glass cell GC. Laser light assigned the second coding pattern PT2 is irradiated into the glass cell GC as the second irradiation light L2 from a direction perpendicular to the first irradiation light L1 and penetrates the cesium in the glass cell GC.

[0097] Thus, in the 3D information acquisition device 1, a light irradiation process is performed in which a first irradiation light L1 and a second irradiation light L2, each having bright pixels bpx and dark pixels dpx, are irradiated from two directions onto a glass cell GC containing cesium that interacts with the first irradiation light L1 and the second irradiation light L2.

[0098] The first irradiation light L1, which has passed through the cesium in the glass cell GC, is received by the first photodetector 15, and the second irradiation light L2, which has passed through the cesium in the glass cell GC, is received by the second photodetector 16.

[0099] Thus, in the 3D information acquisition device 1, a light receiving process is performed in which the first irradiation light L1 and the second irradiation light L2, which are irradiated onto the glass cell GC containing cesium and have passed through the cesium in the glass cell GC, are received by the first photodetector 15 and the second photodetector 16, respectively.

[0100] The optical signal of the first illumination light L1, received by the first photodetector 15, is input to the first lock-in amplifier 22, where its amplitude is measured, and the measured amplitude is input to the personal computer 21. The optical signal of the second illumination light L2, received by the second photodetector 16, is input to the second lock-in amplifier 23, where its amplitude is measured, and the measured amplitude is input to the personal computer 21.

[0101] The personal computer 21 measures the amplitude of the optical signal in the first irradiation light L1 using the first lock-in amplifier 22, and measures the amplitude of the optical signal in the second irradiation light L2 using the second lock-in amplifier 23. Then, it controls the first mirror array device 13 to assign a different first coding pattern PT1 to the laser light, and controls the second mirror array device 14 to assign a different second coding pattern PT2 to the laser light.

[0102] Laser light assigned a different first coding pattern PT1 is irradiated onto the glass cell GC again as the first irradiation light L1, and laser light assigned a different second coding pattern PT2 is irradiated onto the glass cell GC again as the second irradiation light L2. In other words, the light irradiation process is performed again to irradiate the glass cell GC with the first irradiation light L1 having a different first coding pattern PT1 and the second irradiation light L2 having a different second coding pattern PT2.

[0103] The first irradiated light L1, to which a different first coding pattern PT1 has been assigned, is received by the first photodetector 15 after passing through the glass cell GC. The amplitude of the optical signal in the first irradiated light L1 received by the first photodetector 15 is measured by the first lock-in amplifier 22 and input to the personal computer 21.

[0104] The second irradiated light L2, which is assigned a different second coding pattern PT2, is received by the second photodetector 16 after passing through the glass cell GC. The amplitude of the optical signal in the second irradiated light L2 received by the second photodetector 16 is measured by the second lock-in amplifier 23 and input to the personal computer 21.

[0105] In other words, the light receiving process is performed again to receive the first irradiation light L1 having a different first coding pattern PT1 and the second irradiation light L2 having a different second coding pattern PT2, which have been transmitted through the glass cell GC.

[0106] The light irradiation step and the light reception step can be repeated for a first irradiation light L1 having a different first coding pattern PT1 and a second irradiation light L2 having a different second coding pattern PT2.

[0107] Thus, in the 3D information acquisition device 1, the light irradiation process and the acquisition process are performed multiple times using multiple first irradiation lights L1 having different first coding patterns PT1 and multiple second irradiation lights L2 having different second coding patterns PT2.

[0108] When the light irradiation process and acquisition process are performed multiple times, multiple amplitude measurements based on different first coding patterns PT1 and second coding patterns PT2 are input to the personal computer 21.

[0109] In partition cells sc corresponding to different first coding patterns PT1 and different second coding patterns PT2, the positions and number of partition cells sc that constitute the sensitive region Sa are different from each other.

[0110] For example, when a glass cell GC is irradiated with a first irradiation light L1 and a second irradiation light L2 having different encoding patterns than the first encoding pattern PT1 and second encoding pattern PT2 shown in Figure 4, such as the first encoding pattern PT1 and second encoding pattern PT2 shown in Figure 6, the position and number of partition cells sc that become the sensitive region Sa will be different from those of the partition cells sc shown in Figure 4.

[0111] Specifically, in the partition cell sc shown in Figure 6, partition cells sc111, sc131, sc211, sc231, sc321, sc122, sc212, sc232, sc322, sc123, sc213, sc233, and sc323 are sensitive regions Sa.

[0112] Additionally, partition cells sc121, sc221, sc311, sc331, sc112, sc132, sc222, sc312, sc332, sc113, sc133, sc223, sc313, and sc333 are in the insensitive region Da.

[0113] Furthermore, in the partition cell sc shown in Figure 6, there are 13 partition cells sc that are in the sensitive region Sa and 14 partition cells sc that are in the insensitive region Da, while in the partition cell sc shown in Figure 4, there are 15 partition cells sc that are in the sensitive region Sa and 12 partition cells sc that are in the insensitive region Da, showing that the number of sensitive regions Sa and insensitive regions Da differs between the two.

[0114] If the position of the compartment cell sc, which is in the sensitive region Sa, differs within the glass cell GC, the magnitude of the alternating magnetic field applied to the compartment cell sc in the sensitive region Sa will be proportional to the position of the compartment cell sc in the sensitive region Sa.

[0115] Furthermore, the measured amplitude of the optical signal in the first irradiated light L1 having the first coding pattern PT1, and the measured amplitude of the optical signal in the second irradiated light L2 having the second coding pattern PT2, are unique values ​​corresponding to the first coding pattern PT1 and the second coding pattern PT2.

[0116] Therefore, the personal computer 21 can accurately estimate the magnitude of the magnetic field applied to each compartment cell sc within the glass cell GC by using a plurality of first coding patterns PT1 applied to the first illumination light L1, a plurality of second coding patterns PT2 applied to the second illumination light L1, a plurality of amplitude measurements measured based on the optical signals of the plurality of first illumination light L1s, and a plurality of amplitude measurements measured based on the optical signals of the plurality of second illumination light L2s.

[0117] As a result, the personal computer 21 can acquire the three-dimensional magnetic field distribution, which is three-dimensional information within the glass cell GC, with high accuracy. In particular, since the three-dimensional information acquisition device 1 uses cesium, an alkali metal, as the material that interacts with the irradiated light, it is possible to acquire the three-dimensional magnetic field distribution as three-dimensional information within the glass cell GC.

[0118] Thus, after performing the light irradiation process and the light reception process, the personal computer 21 performs an acquisition process to acquire three-dimensional magnetic field distribution, which is three-dimensional information within the glass cell GC, using the first encoded pattern PT1 of the first irradiation light L1 and the second encoded pattern PT2 of the second irradiation light L2 irradiated onto the glass cell GC in the light irradiation process, and the optical signals of the first irradiation light L1 and the second irradiation light L2 received in the light reception process.

[0119] In particular, the personal computer 21 performs an acquisition step after executing the light irradiation step and the light reception step multiple times. In the acquisition step, it uses multiple coded patterns PT1 and PT2 from the multiple light irradiation and light reception steps performed multiple times, along with multiple optical signals from the first irradiation light L1 and multiple optical signals from the second irradiation light L2, to acquire the three-dimensional magnetic field distribution, which is three-dimensional information inside the cesium sealed in the glass cell GC.

[0120] In this case, the personal computer 21 can accurately determine the magnitude of the alternating magnetic field applied to each partition cell sc by performing the light irradiation process and the light reception process more times than the number of partition cells sc partitioned inside the glass cell GC, thereby enabling the acquisition of a highly accurate three-dimensional magnetic field distribution within the glass cell GC.

[0121] Furthermore, when the glass cell GC is irradiated with the first irradiation light L1 and the second irradiation light L2, the first irradiation light L1 and the second irradiation light L2 are irradiated onto the glass cell GC from two orthogonal directions. In this way, by irradiating the glass cell GC with the first irradiation light L1 and the second irradiation light L2 from two orthogonal directions, it becomes possible to clearly demarcate the compartment cell sc that becomes the sensitive region Sa and the compartment cell sc that becomes the insensitive region Da.

[0122] Furthermore, when measuring magnetic fields using conventional magnetic field sensors whose sensor parts are formed with metal wiring, the metal wiring of the sensor part causes spatial distortion and intensity attenuation in the magnetic field being measured. Therefore, if magnetic field sensors are densely arranged to measure multiple points simultaneously, there is a risk of a decrease in measurement accuracy. However, by using a glass cell GC containing alkali metals such as cesium as an optical magnetic sensor, as in the 3D information acquisition device 1, the invasiveness to the magnetic field being measured can be greatly reduced, making it possible to acquire the 3D magnetic field distribution with high accuracy.

[0123] Furthermore, since the magnetic field generated by the metal wire W becomes stronger the closer one is to the metal wire W, the 3D information acquisition device 1 can acquire the 3D magnetic field distribution within the glass cell GC, making it possible to estimate the position of the metal wire W, which is the source of the magnetic field, with high accuracy.

[0124] Furthermore, because the 3D information acquisition device 1 can detect magnetic field sources with high precision, it can be used in industrial fields such as estimating noise sources in electronic circuits and non-destructive testing of bridges and other structures. In addition, it can be used in medical imaging diagnostic devices, such as for detecting the position of magnetic particles within living organisms.

[0125] Furthermore, in the 3D information acquisition device 1 of this embodiment, the amplitude of the optical signals in the first irradiation light L1 and the second irradiation light L2 is used to obtain 3D information within the glass cell GC, but this is not limited to this, and characteristics of the optical signals that change according to the state inside the glass cell GC, such as the polarization of the first irradiation light L1 and the second irradiation light L2, can be used.

[0126] Furthermore, in the 3D information acquisition device 1 of this embodiment, the first irradiation light L1 and the second irradiation light L2 that irradiate the glass cell GC containing cesium from two directions both use laser light that becomes pump light having a wavelength adjusted to the resonance wavelength of cesium, but the device is not limited to this.

[0127] In other words, the first irradiation light L1 and the second irradiation light L2 only need to be capable of dividing the inside of the glass cell GC into regions where an optical signal can be obtained and regions where an optical signal cannot be obtained.

[0128] For example, it is possible to configure a 3D information acquisition device 1 by using a laser beam that acts as a pump beam with a resonant wavelength for the alkali metal as one of the first and second irradiation beams L1 and L2 that irradiate a glass cell GC containing an alkali metal from two directions, and using a laser beam that acts as a probe beam with a wavelength detuned from the resonant wavelength of the alkali metal as the other of the first and second irradiation beams L1 and L2. In this case, it is possible to obtain an optical signal only in the region where the pump beam and the probe beam intersect.

[0129] Furthermore, the first and second irradiation beams L1 and L2 can also be laser beams used in STED microscopes, such as an excitation beam for observation and a STED beam for stimulated emission. [Explanation of symbols]

[0130] 1 3D information acquisition device 11 Light source 13. First Mirror Array Device 14. Second Mirror Array Device 15. First Photodetector 16. Second photodetector 20 controllers 21 Personal Computers 22. First Lock-in Amplifier 23. Second Lock-in Amplifier GC glass cell HC 3D Helmholtz Coil L1 1st irradiation light L2 2nd irradiation light OS1 1st optical system OS2 2nd optical system W metal wire

Claims

1. A light irradiation step in which an irradiated light having an encoded pattern in which bright pixels, which are regions illuminated by light, and dark pixels, which are regions not illuminated by light, are arranged, is irradiated from two directions onto a glass cell containing alkali metals that interact with the irradiated light, A light receiving step is performed in which the irradiated light irradiated onto the glass cell in the light irradiation step is received after passing through the alkali metal in the glass cell, The system includes an acquisition step that uses the encoded pattern of the irradiated light irradiated onto the glass cell in the light irradiation step and the optical signal of the irradiated light received in the light reception step to acquire a three-dimensional magnetic field distribution, which is three-dimensional information inside the glass cell. The light irradiation step and the acquisition step are performed multiple times using multiple irradiation lights having different coding patterns. A method for acquiring three-dimensional information, characterized in that the acquisition step involves acquiring the three-dimensional magnetic field distribution using multiple coding patterns and multiple optical signals from the light irradiation step and the acquisition step, which are performed multiple times.

2. The method for acquiring three-dimensional information according to claim 1, wherein in the light irradiation step, the irradiation light is irradiated onto the glass cell from two orthogonal directions.

3. The glass cell has a plurality of partitioned cells that are partitioned by the encoding pattern of the irradiation light irradiated from two directions, The method for acquiring three-dimensional information according to claim 1 or claim 2, wherein the light irradiation step and the light receiving step are performed a number of times equal to or greater than the number of partition cells in the glass cell.

4. The method for acquiring three-dimensional information according to claim 1 or claim 2, wherein the optical signal changes depending on the magnitude of the magnetic field applied to the alkali metal.

5. The method for acquiring three-dimensional information according to claim 1 or claim 2, wherein the irradiating light is a laser light having a resonance wavelength for the alkali metal and a circularly polarized component.

6. A light source that emits light, A glass cell containing an alkali metal that interacts with light, A first optical system that assigns a first coding pattern to light emitted from the light source, in which bright pixels are regions illuminated by light and dark pixels are regions not illuminated by light, and irradiates the glass cell with the first illumination light to which the first coding pattern has been assigned. A second optical system is provided which a second coding pattern is applied to the light emitted from the light source, the pattern being arranged in a way that bright pixels are regions illuminated by light and dark pixels are regions not illuminated by light, and the second illumination light, which is the light to which the second coding pattern is applied, is irradiated onto the glass cell from a direction different from the irradiation direction of the first illumination light. A first photodetector that receives the first irradiation light that has passed through the alkali metal in the glass cell, A second photodetector that receives the second irradiation light transmitted through the alkali metal in the glass cell, A controller that acquires a three-dimensional magnetic field distribution, which is three-dimensional information inside the glass cell, using the first coding pattern, the second coding pattern, the optical signal of the first irradiation light received by the first photodetector, and the optical signal of the second irradiation light received by the second photodetector, Equipped with, The controller is a three-dimensional information acquisition device characterized by acquiring the three-dimensional magnetic field distribution inside the glass cell using a plurality of different first coding patterns, a plurality of different second coding patterns, a plurality of optical signals of the first illumination light corresponding to the plurality of different first coding patterns, and a plurality of optical signals of the second illumination light corresponding to the plurality of different second coding patterns.

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