Three-dimensional information acquisition method and three-dimensional information acquisition device

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]

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

[0002] As disclosed in Patent Document 1, a conventional optical pumping magnetometer is known that includes a cell containing an alkali metal atomic group, a pump light optical system for inputting pump light into the cell, a first probe light optical system for inputting first probe light so that it intersects with the pump light within the cell, a second probe light optical system for irradiating second probe light so that it intersects with the pump light and the first probe light within the cell, a first detector for detecting a 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 application means for applying a static magnetic field within the cell, and a calculation means for calculating information on magnetic field strengths in two different directions within the cell from the rotation angle detected by the first detector and the rotation angle detected by the second detector.

[0003] In such a magnetometer, it is possible to obtain information about the magnetic field strength in two different directions in a substance, such as a group of alkali metal atoms, contained in a cell and which interacts with light. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6184109 Summary of the Invention [Problem to be solved by the invention]

[0005] In the optically pumped magnetometer with the configuration disclosed in Patent Document 1, it is possible to obtain information regarding the magnetic field strength in two different directions within a cell, i.e., two-dimensional information regarding the magnetic field strength within a substance contained in the cell, but it has been difficult to obtain three-dimensional information within the substance.

[0006] The present invention has been made in consideration of the above-mentioned circumstances, and provides a three-dimensional information acquisition method and a three-dimensional information acquisition device that can acquire three-dimensional information inside a substance that interacts with light. [Means for solving the problem]

[0007] That is, the three-dimensional information acquisition method includes a light irradiation step of irradiating a material that interacts with the irradiation light from two directions with irradiation light having a coding pattern in which bright pixels, which are areas where light is irradiated, and dark pixels, which are areas where light is not irradiated, are arranged, a light receiving step of receiving the irradiation light that is irradiated to the material in the light irradiation step and has passed through the material, and an acquisition step of acquiring three-dimensional information within the material using the coding pattern of the irradiation light irradiated to the material in the light irradiation step and an optical signal of the irradiation light received in the light receiving step, and the light irradiation step and the acquisition step are performed multiple times using multiple irradiation lights having different coding patterns, and in the acquisition step, the three-dimensional information is acquired using the multiple coding patterns and the multiple optical signals in the light irradiation step and the acquisition step that have been performed multiple times.

[0008] This makes it possible to obtain three-dimensional information within a substance with high accuracy.

[0009] In the light irradiation step, the material is irradiated with the irradiation light from two directions perpendicular to each other.

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

[0011] In addition, the material has a plurality of partition cells that are partitioned by the coding pattern of the irradiated light from two directions, and the light irradiating process and the light receiving process are performed a number of times greater than or equal to the number of partition cells that the material has.

[0012] This makes it possible to obtain three-dimensional information within the material with high accuracy.

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

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

[0015] The substance is an alkali metal, and the irradiated light is laser light that has a resonant wavelength for the alkali metal and also has a circularly polarized component.

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

[0017] The three-dimensional information acquisition device further includes a light source that emits light, a material that interacts with the light, a first optical system that imparts a first coded pattern to the light emitted from the light source, in which bright pixels that are areas where the light is irradiated and dark pixels that are areas where the light is not irradiated are arranged, and irradiates the material with first irradiation light, which is the light to which the first coded pattern is imparted, a second optical system that imparts a second coded pattern to the light emitted from the light source, in which bright pixels that are areas where the light is irradiated and dark pixels that are areas where the light is not irradiated are arranged, and irradiates the material with second irradiation light, which is the light to which the second coded pattern is imparted, from a direction different from the irradiation direction of the first irradiation light, and a second optical system that imparts the first coded pattern to the light emitted from the light source, in which bright pixels that are areas where the light is irradiated and dark pixels that are areas where the light is not irradiated, from a direction different from the irradiation direction of the first irradiation light. the optical receiver for receiving the second irradiation light that has passed through the material; and a controller for acquiring three-dimensional information about the inside of the material using the first coded pattern, the second coded pattern, an optical signal of the first irradiation light received by the first optical receiver, and an optical signal of the second irradiation light received by the second optical receiver, wherein the controller acquires three-dimensional information about the inside of the material using a plurality of different first coded patterns, a plurality of different second coded patterns, a plurality of optical signals of the first irradiation light corresponding to the plurality of different first coded patterns, and a plurality of optical signals of the second irradiation light corresponding to the plurality of different second coded patterns.

[0018] This makes it possible to obtain three-dimensional information within the material with high accuracy. Effect of the Invention

[0019] According to the present invention, three-dimensional information within a substance can be obtained with high accuracy. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic diagram showing a three-dimensional information acquisition device. [Diagram 2] FIG. 2 shows a first mirror array device. [Diagram 3]FIG. 2 is a perspective view showing a state in which a first irradiation light having a first coding pattern and a second irradiation light having a second coding pattern are irradiated onto a glass cell. [Figure 4] FIG. 2 is an exploded perspective view showing partition cells in a glass cell irradiated with first and second irradiation lights. [Diagram 5] FIG. 13 is a diagram showing a pattern of sensitive areas and insensitive areas in an upper layer partition cell when a first exposure light and a second exposure light are irradiated onto a glass cell. [Figure 6] FIG. 5 is an exploded perspective view showing partition cells in a glass cell irradiated with first and second irradiation lights having first and second coding patterns different from the first and second irradiation lights irradiated to the glass cell shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0022] [Overview of 3D information acquisition methods] The three-dimensional information acquisition method of the present invention includes a light irradiation step of irradiating a material that interacts with the irradiation light from two directions with irradiation light having a coding pattern in which bright pixels, which are areas where light is irradiated, and dark pixels, which are areas where light is not irradiated, are arranged, a light receiving step of receiving the irradiation light that is irradiated to the material in the light irradiation step and has passed through the material, and an acquisition step of acquiring three-dimensional information inside the material using the coding pattern of the irradiation light irradiated to the material in the light irradiation step and an optical signal of the irradiation light received in the light receiving step, wherein the light irradiation step and the acquisition step are performed a plurality of times using a plurality of irradiation lights having different coding patterns, and in the acquisition step, the three-dimensional information is acquired using the plurality of coding patterns and the plurality of optical signals in the light irradiation step and the acquisition step that have been performed a plurality of times.

[0023] In this case, the substance that interacts with the irradiated light can be, for example, an alkali metal such as cesium, potassium, rubidium, etc. Furthermore, the irradiated light that interacts with the substance can be light having a circularly polarized component.

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

[0025] The light that spin-polarizes the atoms that make up a substance is called "pump light." Moreover, the process of spin-polarizing the atoms that make up a substance using pump light is called "optical pumping."

[0026] The pump light is preferably composed of only circularly polarized light, but is not limited thereto, and may contain other polarized components as long as it has a circularly polarized component. In addition, the pump light has a wavelength at which an alkali metal undergoes an optical transition from the ground level to the excited level.

[0027] When a static magnetic field is applied, the spin polarization of the material produced by optical pumping undergoes precession at a Larmor frequency determined by the magnitude of the magnetic field.

[0028] When an AC magnetic field is applied to a material with a static magnetic field applied, the phase of the precession is aligned by the applied AC magnetic field, and the irradiated light passing through the material is intensity-modulated according to the magnetic field and is emitted from the material. The alkali metal that constitutes the material has the property that when a magnetic field is applied, the light transmittance changes according to the strength of the magnetic field.

[0029] In the three-dimensional information acquisition method, for example, the three-dimensional distribution state of the magnetic field inside the material can be acquired as three-dimensional information inside the material.

[0030] [3D information acquisition device] Next, a three-dimensional information acquiring device used when carrying out the three-dimensional information acquiring method will be described.

[0031] The three-dimensional information acquisition device 1 shown in Figure 1 includes 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 three-dimensional Helmholtz coil HC, and a metal wire W.

[0032] The glass cell GC is a sealed cubic container made of glass, in which cesium, an alkali metal, is sealed in gaseous form. For example, a 30 mm cube glass cell can be used as the 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, it is possible to optimize the detection sensitivity and sensitivity bandwidth of the glass cell GC.

[0033] In the three-dimensional information acquisition device 1, a three-dimensional Helmholtz coil HC is disposed so as to surround the glass cell GC, and a static magnetic field is applied to the glass cell GC by the three-dimensional Helmholtz coil HC.

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

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

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

[0037] A half-wave plate 31 is disposed between the light source 11 and the polarizing beam splitter 12, and the laser light emitted from the light source 11 passes through the half-wave plate 31 and then enters the polarizing beam splitter 12. The laser light emitted from the light source 11 can have its light amount appropriately adjusted by an aperture and can be reflected by a mirror before entering the polarizing beam splitter 12.

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

[0039] The laser light emitted from the polarizing beam splitter 12 passes through the quarter-wave plate 32 and then enters the first mirror array device 13. The laser light emitted from the polarizing beam splitter 12 becomes circularly polarized light by 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 and then enters the second mirror array device 14. The laser light emitted from the polarizing beam splitter 12 becomes circularly polarized light by passing through the quarter-wave plate 33.

[0041] The first mirror array device 13 is a reflecting member that reflects the laser light incident on the first mirror array device 13 and irradiates it onto the glass cell GC, and when reflecting the laser light incident on the first mirror array device 13, it imparts a first coding pattern PT1 to the laser light. The first coding pattern PT1 is a pattern in which bright pixels bpx, which are areas where light is irradiated, and dark pixels dpx, which are areas where light is not irradiated, are arranged. The first coding pattern PT1 is an example of a coding pattern.

[0042] 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 lattice pattern in rows and columns.

[0043] The micromirror 132 can reflect the laser light incident on the first mirror array device 13, and can move between an ON position (the position of the micromirror 132a in FIG. 2(a)) and an OFF position (the position of the micromirror 132b in FIG. 2(a)) having different tilt directions. The micromirror 132 is driven under the control of the controller 20, and can be switched between the ON position and the OFF position.

[0044] The laser light reflected by the micromirror 132 in the ON position is irradiated onto the glass cell GC, and the laser light reflected by the micromirror 132 in the OFF position is not irradiated onto the glass cell GC.

[0045] Therefore, by individually driving each micromirror 132 to an on or off position, the laser light reflected by the first mirror array device 13 can be given a first coding pattern PT1 in which bright pixels bpx, which are areas where light is irradiated, and dark pixels dpx, which are areas where light is not irradiated, are arranged.

[0046] As shown in Fig. 2(b), in the first coding pattern PT1, a plurality of pixels px are arranged in a lattice pattern, and each pixel px is either a bright pixel bpx, which is an area where light is irradiated, or a dark pixel dpx, which is an area where light is not irradiated. Each pixel px in the first coding pattern PT1 is formed in a rectangular shape. In the first coding pattern PT1 shown in Fig. 2(b), five rows of pixels px are arranged in the row direction, and five columns of pixels px are arranged in the column direction.

[0047] The 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 micromirror 132a in the on position, and the dark pixels dpx are formed when laser light incident on the first mirror array device 13 is reflected by the micromirror 132b in the off position.

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

[0049] The second coding pattern PT2 is a pattern in which light pixels bpx, which are areas where light is irradiated, and dark pixels dpx, which are areas where light is not irradiated, are arranged, and is configured in the same manner 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 comprises a substrate 141 and micromirrors 142 which correspond to the substrate 131 and micromirrors 132 of the first mirror array device 13 .

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

[0052] The 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 micromirror 142a in the on position, and the dark pixels dpx are formed when laser light incident on the second mirror array device 14 is reflected by the micromirror 142b in the off position.

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

[0054] In the three-dimensional 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, a lens, etc. constitute a first optical system OS1 that imparts a first coding pattern PT1 to the laser light emitted from the light source 11 and irradiates the first irradiation light L1 to which the first coding pattern PT1 has been imparted onto the glass cell GC.

[0055] In addition, in the three-dimensional information acquisition device 1, a second optical system OS2 is configured by a polarizing beam splitter 12, a second mirror array device 14, a half-wave plate 31, a quarter-wave plate 33, a lens, etc., which imparts a second coding pattern PT2 to the laser light emitted from the light source 11 and irradiates the second irradiation light L2 to which the second coding pattern PT2 has been imparted onto the glass cell GC.

[0056] 1 and 3, the irradiation direction of the first irradiation light L1 on the glass cell GC is perpendicular to the irradiation direction of the second irradiation light L2 on the glass cell GC. 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 perpendicular to the X direction. In addition, the direction perpendicular to the X direction and the Y direction and going from the top to the bottom in FIG. 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 irradiated onto the glass cell GC passes through the glass cell GC, which is the space for acquiring three-dimensional information, while retaining the first coding pattern PT1. Similarly, the second irradiation light L2 irradiated onto the glass cell GC passes through the glass cell GC, which is the space for acquiring three-dimensional information, while retaining the second coding pattern PT2.

[0058] The first coding pattern PT1 and the second coding pattern PT2 shown in Fig. 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 coding pattern PT1, the pixels px in the upper row are defined as pixel px011, pixel px021, and pixel px031, from upstream to downstream in the Y direction, the pixels px in the middle row are defined as pixel px012, pixel px022, and pixel px032, from upstream to downstream in the Y direction, and the pixels px in the lower row are defined as pixel px013, pixel px023, and pixel px033, from upstream to downstream in the Y direction.

[0060] In the first coding pattern PT1 shown in FIG. 3, pixels px011, px013, px022, px023, and px031 are set as light pixels bpx, and pixels px012, px021, px032, and px033 are set as dark pixels dpx.

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

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

[0063] As shown in Fig. 4, in the glass cell GC, partitioned cells sc can be defined corresponding to each pixel px of the first coding pattern PT1 and the second coding pattern PT2. Specifically, the first coding pattern PT1 having pixels px in 3 rows and 3 columns intersects with the second coding pattern PT2 having pixels px in 3 rows and 3 columns, thereby defining a total of 27 partition cells sc in 3 rows, 3 columns and 3 layers. 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] Regarding the partition cells sc, the partition cells sc of a row located at the upper layer in the Z direction and upstream in the Y direction are defined as partition cells sc111, sc211, and sc311, from the upstream side to the downstream side in the X direction, the partition cells sc of a row located at the upper layer in the Z direction and midstream in the Y direction are defined as partition cells sc121, sc221, and sc321, from the upstream side to the downstream side in the X direction, and the partition cells sc of a row located at the upper layer in the Z direction and downstream in the Y direction are defined as partition cells sc131, sc231, and sc331, from the upstream side to the downstream side in the X direction.

[0065] In addition, with regard to the partition cells sc, the partition cells sc of a row located in the middle layer in the Z direction and upstream in the Y direction are defined as partition cells sc112, sc212, and sc312, from the upstream side to the downstream side in the X direction, the partition cells sc of a row located in the middle layer in the Z direction and midstream in the Y direction are defined as partition cells sc122, sc222, and sc322, from the upstream side to the downstream side in the X direction, and the partition cells sc of a row located in the middle layer in the Z direction and downstream in the Y direction are defined as partition cells sc132, sc232, and sc332, from the upstream side to the downstream side in the X direction.

[0066] Furthermore, with regard to the partition cells sc, the partition cells sc of the rows located at the lower layer in the Z direction and upstream in the Y direction are defined as partition cells sc113, sc213, and sc313, from the upstream side to the downstream side in the X direction, the partition cells sc of the rows located at the lower layer in the Z direction and midstream in the Y direction are defined as partition cells sc123, sc223, and sc323, from the upstream side to the downstream side in the X direction, and the partition cells sc of the rows located at the lower layer in the Z direction and downstream in the Y direction are defined as partition cells sc133, sc233, and sc333, from the upstream side to the downstream side in the X direction.

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

[0068] In the glass cell GC irradiated with the second irradiation light L2, in the region corresponding to the bright pixels bpx of the second coding pattern PT2, the cesium sealed in the glass cell GC is spin polarized, forming a sensitive region Sa that is sensitive to the magnetic field. On the other hand, in the glass cell GC irradiated with the second irradiation light L2, in the region corresponding to the dark pixels dpx of the second coding pattern PT2, the cesium in the glass cell GC is not spin polarized, forming 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 pixel bpx of the first coding pattern PT1 intersects with the region corresponding to the bright pixel bpx of the second coding pattern PT2, cesium cannot be spin-polarized in orthogonal directions by either the first irradiation light L1 or the second irradiation light L2, and therefore this region becomes an insensitive region Da that has no sensitivity to magnetic fields, just like the region where neither the first irradiation light L1 nor the second irradiation light L2 passes through.

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

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

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

[0073] In addition, regarding the partition cells sc in the glass cell GC, if the partition cells sc that become the sensitive area Sa are represented by “1” or “−1” and the partition cells sc that become the insensitive area Da are represented by “0”, the partition cells sc111 to sc331 in the upper layer of the glass cell GC are represented as shown in FIG. 5.

[0074] In other words, partition cell sc111 where pixel px011, which is a bright pixel bpx, intersects with pixel px101, which is a dark pixel dpx; partition cell sc131 where pixel px031, which is a bright pixel bpx, intersects with pixel px101, which is a dark pixel dpx; partition cell sc221 where pixel px021, which is a dark pixel dpx, intersects with pixel px201, which is a bright pixel bpx; partition cell sc311 where pixel px011, which is a bright pixel bpx, intersects with pixel px301, which is a dark pixel dpx; and partition cell sc331 where pixel px031, which is a bright pixel bpx, intersects with pixel px301, which is a dark pixel dpx; are spin polarized and become sensitive regions Sa, and are represented by "1" or "-1."

[0075] On the other hand, partition cell sc121 where pixel px021, which is a dark pixel dpx, intersects with pixel px101, which is a dark pixel dpx; partition cell sc211 where pixel px011, which is a bright pixel bpx, intersects with pixel px201, which is a bright pixel bpx; partition cell sc231 where pixel px031, which is a bright pixel bpx, intersects with pixel px201, which is a bright pixel bpx; and partition cell sc321 where pixel px021, which is a dark pixel dpx, intersects with pixel px301, which is a dark pixel dpx, are not spin polarized and become insensitive areas Da, represented by "0."

[0076] In addition, with regard to the partition cells sc112 to sc332 in the middle layer and the partition cells sc113 to sc333 in the lower layer in the glass cell GC, partition cell sc112, partition cell sc132, partition cell sc212, partition cell sc232, partition cell sc322, partition cell sc113, partition cell sc123, partition cell sc213, partition cell sc223, and partition cell sc333 are spin polarized and become sensitive regions Sa.

[0077] On the other hand, the partition cells sc122, sc222, sc312, sc332, sc133, sc233, sc313, and sc323 are not spin polarized and become insensitive regions Da.

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

[0079] The controller 20 includes 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. The three-dimensional Helmholtz coil HC and the metal wire W are connected to the signal generator 24.

[0080] The optical signal of the first irradiation light L1 received by the first photodetector 15 is an optical signal acquired from the partitioned cell sc which is the sensitive region Sa in the first irradiation light L1, and no optical signal is acquired from the partitioned cell sc which is the insensitive region Da. The intensity of the optical signal of the first irradiation light L1 received by the first photodetector 15 is modulated by an AC magnetic field applied inside the glass cell GC. The optical signal of the first irradiation light L1 acquired by the first photodetector 15 is input to the first lock-in amplifier 22, and the first lock-in amplifier 22 performs phase detection to measure the amplitude of the modulated optical signal.

[0081] The optical signal of the second irradiation light L2 received by the second photodetector 16 is an optical signal acquired from the partitioned cell sc which is the sensitive region Sa in the second irradiation light L2, and no optical signal is acquired from the partitioned cell sc which is the insensitive region Da. The intensity of the optical signal of the second irradiation light L2 received by the second photodetector 16 is modulated by an AC magnetic field applied inside the glass cell GC. The optical signal of the second irradiation 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 by the second lock-in amplifier 23. A reference signal is input from a signal generator 24 to the first lock-in amplifier 22 and the second lock-in amplifier 23.

[0082] In the partition cell sc which is the sensitive area Sa, the amplitude of the transmitted optical signal varies depending on the magnitude of the applied AC magnetic field, and the stronger the AC magnetic field applied to the partition cell sc, the greater the amplitude of the optical signal transmitted through the partition cell sc.

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

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

[0085] The optical signal of the first irradiation light L1 acquired by the first photodetector 15 is a sum of optical signals corresponding to each partitioned cell sc which is the sensitive area Sa in the first irradiation light L1, and is represented by the magnitude of the amplitude measured by the first lock-in amplifier 22. Therefore, the magnitude of the amplitude measured by the first lock-in amplifier 22 varies depending on the number of partitioned cells sc which are the sensitive area Sa included in the first irradiation light L1 and the magnitude of the AC magnetic field applied to the partitioned cells sc which are the sensitive area Sa.

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

[0087] The amplitude measurement value obtained by the first lock-in amplifier 22 and the amplitude measurement value obtained by the second lock-in amplifier 23 are input to the personal computer 21 .

[0088] The personal computer 21 controls the driving of the micromirrors 132 in the first mirror array device 13, and can switch the micromirrors 132 between the on position and the off position. This makes it possible to form a plurality of different first coding patterns PT1.

[0089] The personal computer 21 controls the driving of the micromirrors 142 in the second mirror array device 14 to switch the micromirrors 142 between the on position and the off position, thereby forming a plurality of different second coding patterns PT2.

[0090] In the three-dimensional 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 multiple optical signals of the first irradiation light L1 are acquired by a first photodetector 15, and multiple optical signals of the second irradiation light L2 are acquired by a second photodetector 16.

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

[0092] The personal computer 21 is capable of acquiring a three-dimensional distribution of the AC magnetic field, which is three-dimensional information within the glass cell GC, by using a plurality of different first coding patterns PT1, a plurality of different second coding patterns PT2, amplitude measurement values ​​based on the optical signals of a plurality of first irradiation light L1 corresponding to the plurality of different first coding patterns PT1, and amplitude measurement values ​​based on the optical signals of a plurality of second irradiation light L2 corresponding to the plurality of different second coding patterns PT2.

[0093] [Execution of 3D information acquisition method by 3D information acquisition device] When the three-dimensional information acquisition method is executed by the three-dimensional information acquisition device 1, first, laser light is emitted from the light source 11 under the control of the personal computer 21. In this case, the laser light emitted from the light source 11 is adjusted to 852 nm, which is the resonance wavelength of 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 so as to impart the first encoding pattern PT1 to the laser light emitted from the light source 11, which has passed through the half-wave plate 31 and the quarter-wave plate 32 and become circularly polarized, when the laser light is reflected by the first mirror array device 13.

[0095] Similarly, the personal computer 21 controls the operation of the micromirrors 142 in the second mirror array device 14 to impart the 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, when the laser light is reflected by the second mirror array device 14.

[0096] The laser light having the first coding pattern PT1 is irradiated as the first irradiation light L1 into the glass cell GC and passes through the cesium in the glass cell GC. The laser light having the second coding pattern PT2 is irradiated as the second irradiation light L2 into the glass cell GC from a direction perpendicular to the first irradiation light L1 and passes through the cesium in the glass cell GC.

[0097] In this way, in the three-dimensional information acquisition device 1, a light irradiation process is executed in which the first irradiation light L1 and the second irradiation light L2 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 that has passed through the cesium in the glass cell GC is received by a first photodetector 15, and the second irradiation light L2 that has passed through the cesium in the glass cell GC is received by a second photodetector 16.

[0099] In this manner, in the three-dimensional information acquisition device 1, a light receiving process is executed in which the first irradiation light L1 and the second irradiation light L2 that are irradiated onto the glass cell GC in which cesium is sealed and transmitted 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 irradiation light L1 received by the first photodetector 15 is input to a first lock-in amplifier 22 to measure the amplitude, and the measured amplitude value is input to the personal computer 21. The optical signal of the second irradiation light L2 received by the second photodetector 16 is input to a second lock-in amplifier 23 to measure the amplitude, and the measured amplitude value is input to the personal computer 21.

[0101] After the amplitude of the optical signal in the first irradiation light L1 is measured by the first lock-in amplifier 22 and the amplitude of the optical signal in the second irradiation light L2 is measured by the second lock-in amplifier 23, the personal computer 21 controls the first mirror array device 13 to impart a first encoding pattern PT1, which is different from the previous time, to the laser light, and controls the second mirror array device 14 to impart a second encoding pattern PT2, which is different from the previous time, to the laser light.

[0102] The laser light having the different first coding pattern PT1 is irradiated to the glass cell GC again as the first irradiation light L1, and the laser light having the different second coding pattern PT2 is irradiated to the glass cell GC again as the second irradiation light L2. That is, the light irradiation step is executed again to irradiate the glass cell GC with the first irradiation light L1 having the different first coding pattern PT1 and the second irradiation light L2 having the different second coding pattern PT2.

[0103] The first irradiation light L1 having a different first coding pattern PT1 imparted thereto is received by the first photodetector 15 after passing through the glass cell GC, and the amplitude of the optical signal in the first irradiation 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 irradiation light L2 having a different second coding pattern PT2 is received by the second photodetector 16 after passing through the glass cell GC, and the amplitude of the optical signal in the second irradiation 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] That is, the light receiving step is executed again to receive the first irradiation light L1 having the different first coding pattern PT1 and the second irradiation light L2 having the different second coding pattern PT2 that have passed through the glass cell GC.

[0106] The light irradiating and receiving steps can be further 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] In this way, in the three-dimensional 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 step and the acquisition step are performed multiple times, multiple amplitude measurement values ​​based on different first and second coding patterns PT1 and PT2 are input to the personal computer 21.

[0109] The positions and the number of the divided cells sc that become the sensible areas Sa are different from each other in the divided cells sc that correspond to the different first coding patterns PT1 and the different second coding patterns PT2.

[0110] For example, when a first irradiation light L1 and a second irradiation light L2 having coding patterns different from the first coding pattern PT1 and the second coding pattern PT2 shown in Figure 4, such as the first coding pattern PT1 and the second coding pattern PT2 shown in Figure 6, are irradiated onto a glass cell GC, the positions and number of the partition cells sc that become the sensitive area Sa are different from those of the partition cells sc shown in Figure 4.

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

[0112] Furthermore, partition cell sc121, partition cell sc221, partition cell sc311, partition cell sc331, partition cell sc112, partition cell sc132, partition cell sc222, partition cell sc312, partition cell sc332, partition cell sc113, partition cell sc133, partition cell sc223, partition cell sc313, and partition cell sc333 are insensitive areas Da.

[0113] Furthermore, in the divided cell sc shown in Figure 6, there are 13 divided cells sc that become sensitive regions Sa and 14 divided cells sc that become insensitive regions Da, and in the divided cell sc shown in Figure 4, there are 15 divided cells sc that become sensitive regions Sa and 12 divided cells sc that become insensitive regions Da, and the numbers of sensitive regions Sa and insensitive regions Da in both cases are different.

[0114] When the position of the partitioned cell sc that becomes the sensitive region Sa in the glass cell GC is different, the magnitude of the AC magnetic field applied to the partitioned cell sc that becomes the sensitive region Sa varies depending on the position of the partitioned cell sc that becomes the sensitive region Sa.

[0115] In addition, the measured value of the amplitude of the optical signal in the first irradiation light L1 having the first encoding pattern PT1 and the measured value of the amplitude of the optical signal in the second irradiation light L2 having the second encoding pattern PT2 are unique values ​​corresponding to the first encoding pattern PT1 and the second encoding pattern PT2.

[0116] Therefore, the personal computer 21 can accurately estimate the magnitude of the magnetic field applied to each partition cell sc in the glass cell GC using the multiple first coding patterns PT1 imparted to the first irradiation light L1, the multiple second coding patterns PT2 imparted to the second irradiation light L1, the multiple amplitude measurement values ​​measured based on the multiple optical signals of the first irradiation light L1, and the multiple amplitude measurement values ​​measured based on the multiple optical signals of the second irradiation light L2.

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

[0118] In this way, after executing the light irradiation process and the light receiving process, the personal computer 21 executes an acquisition process to acquire three-dimensional magnetic field distribution, which is three-dimensional information within the glass cell GC, using the first coding pattern PT1 of the first irradiation light L1 and the second coding pattern PT2 of the second irradiation light L2 irradiated to the glass cell GC in the light irradiation process, and the optical signals of the first irradiation light L1 and the optical signals of the second irradiation light L2 received in the light receiving process.

[0119] In particular, the personal computer 21 executes the light irradiation process and the light receiving process multiple times and then executes the acquisition process, in which a three-dimensional magnetic field distribution, which is three-dimensional information about the inside of the cesium sealed in the glass cell GC, is acquired using the multiple coding patterns PT1 and the multiple coding patterns PT2, and the multiple optical signals of the first irradiation light L1 and the multiple optical signals of the second irradiation light L2, obtained in the multiple light irradiation processes and the multiple light receiving processes.

[0120] In this case, the personal computer 21 executes the light irradiation process and the light receiving process a number of times equal to or greater than the number of partition cells sc partitioned inside the glass cell GC, thereby enabling the magnitude of the AC magnetic field applied to each partition cell sc to be accurately determined, and the three-dimensional magnetic field distribution within the glass cell GC to be obtained with high accuracy.

[0121] In addition, when the first irradiation light L1 and the second irradiation light L2 are irradiated onto the glass cell GC, 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 is possible to clearly divide the glass cell GC into a partition cell sc that becomes the sensitive region Sa and a partition cell sc that becomes the insensitive region Da.

[0122] Furthermore, when measuring a magnetic field using a conventional magnetic field sensor whose sensor section is formed of metal wiring, the metal wiring of the sensor section causes spatial distortion and intensity attenuation in the magnetic field to be measured, so if magnetic field sensors are densely arranged to measure multiple points simultaneously, there is a risk of reducing the measurement accuracy. However, by using a glass cell GC filled with an alkali metal such as cesium as an optical magnetic sensor, as in the three-dimensional information acquisition device 1, it is possible to greatly reduce the invasiveness of the magnetic field to be measured, and to acquire a three-dimensional magnetic field distribution with high accuracy.

[0123] In addition, since the magnetic field generated from the metal wire W becomes stronger the closer it is to the metal wire W, by acquiring the three-dimensional magnetic field distribution within the glass cell GC using the three-dimensional information acquisition device 1, it is possible to estimate the position of the metal wire W, which is the source of the magnetic field, with high accuracy.

[0124] In addition, since the three-dimensional information acquisition device 1 can detect the source of a magnetic field with high accuracy, it can be used in industrial fields such as estimation of noise sources in electronic circuits and non-destructive inspection of bridges, etc. Furthermore, it can be used in image diagnostic devices in the medical field, such as for detecting the position of magnetic particles in a living body.

[0125] In addition, in the three-dimensional 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 three-dimensional information within the glass cell GC, but this is not limited to this, and characteristics of the optical signals that change depending on the conditions within the glass cell GC, such as the polarization of the first irradiation light L1 and the second irradiation light L2, can be used.

[0126] In addition, in the three-dimensional information acquisition device 1 of this embodiment, the first irradiation light L1 and the second irradiation light L2 that are irradiated from two directions to the glass cell GC in which cesium is sealed are both laser light that serves as pump light having a wavelength adjusted to the resonance wavelength of cesium, but this is not limited to this.

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

[0128] For example, it is possible to configure the three-dimensional information acquisition device 1 by using a laser beam as a pump beam having a resonant wavelength for the alkali metal as one of the first irradiation light L1 and the second irradiation light L2 irradiated from two directions onto a glass cell GC in which an alkali metal is sealed, and using a laser beam as a probe beam having a wavelength detuned from the resonant wavelength of the alkali metal as the other of the first irradiation light L1 and the second irradiation light L2. In this case, it is possible to obtain an optical signal only in the region where the pump light and the probe light intersect.

[0129] Furthermore, as the first irradiation light L1 and the second irradiation light L2, a laser light (Excitation beam) used as excitation light for observation and a laser light (STED beam) for stimulated emission used in an STED microscope can also be used. [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 Controller 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 of irradiating a substance that interacts with the irradiation light from two directions with irradiation light having a coding pattern in which bright pixels, which are regions to be irradiated with light, and dark pixels, which are regions to be not irradiated with light, are arranged; a light receiving step of receiving the irradiation light that has been irradiated to the substance in the light irradiating step and has transmitted through the substance; an acquisition step of acquiring three-dimensional information about the inside of the material by using the coded pattern of the irradiated light irradiated to the material in the light irradiating step and an optical signal of the irradiated light received in the light receiving step, The light irradiation step and the acquisition step are performed a plurality of times using a plurality of irradiation lights having different coding patterns; A three-dimensional information acquisition method characterized in that, in the acquisition step, the three-dimensional information is acquired using a plurality of the coding patterns and a plurality of the optical signals in the light irradiation step and the acquisition step which are executed a plurality of times.

2. The three-dimensional information acquiring method according to claim 1 , wherein in the light irradiation step, the irradiation light is irradiated onto the substance from two directions perpendicular to each other.

3. the substance has a plurality of partitioned cells partitioned by the coding pattern of the irradiation light irradiated from two directions, 3. The three-dimensional information acquisition method according to claim 1, wherein the light irradiating step and the light receiving step are performed a number of times equal to or greater than the number of the partition cells that the substance has.

4. the optical signal varies depending on the magnitude of a magnetic field applied to the substance; The three-dimensional information acquiring method according to claim 1 , wherein the three-dimensional information is a three-dimensional magnetic field distribution inside the substance.

5. the substance is an alkali metal; 3. The method for acquiring three-dimensional information according to claim 1, wherein the irradiated light is a laser light having a resonant wavelength for an alkali metal and having a circularly polarized component.

6. A light source that emits light; the light-interactive material; and a first optical system that provides a first coded pattern to the light emitted from the light source, in which bright pixels that are regions to be irradiated with light and dark pixels that are regions to be not irradiated with light are arranged, and irradiates the substance with first irradiation light, which is the light provided with the first coded pattern; a second optical system that imparts a second coded pattern to the light emitted from the light source, in which bright pixels that are areas irradiated with light and dark pixels that are areas not irradiated with light are arranged, and irradiates the material with second irradiation light, which is the light imparted with the second coded pattern, from a direction different from the irradiation direction of the first irradiation light; a first light receiver that receives the first irradiation light that has passed through the substance; a second light receiver that receives the second irradiation light that has passed through the substance; a controller that acquires three-dimensional information about the inside of the material by using the first coded pattern, the second coded pattern, an optical signal of the first irradiation light received by the first optical receiver, and an optical signal of the second irradiation light received by the second optical receiver; Equipped with The three-dimensional information acquisition device is characterized in that 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 a plurality of different first coding patterns, and a plurality of optical signals of the second irradiation light corresponding to a plurality of different second coding patterns.

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