Measurement device, measurement method and program

Abstract

To provide a measurement device that enables a highly accurate distance measurement in a wide measurement range.SOLUTION: A measurement device (10) has: a light source unit (1) that emits measurement light with a prescribed light intensity distribution to a measurement object; an image-capturing unit (2) that image-forms the measurement light diffused or reflected by the measurement object; and a computation unit (3) that conducts a computation, using output data from the image-capturing unit. The image-capturing unit has a light detection unit (14) that measures the light intensity distribution obtained by the measurement light, and the computation unit is configured to compute a distance up to the measurement object on the basis of a Time of Flight of light up to the measurement object and the light intensity distribution obtained by the measurement light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a measurement device, a measurement method, and a program. [Background technology]

[0002] Patent Document 1 discloses a distance measurement method using a Time of Flight (TOF) method that measures distance from the time of flight of light. Patent Document 2 discloses a measurement method that projects a stripe pattern onto an object and measures the shape of the object from the phase difference of the stripe pattern. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-96905 A [Patent Document 2] JP 2019-90782 A Summary of the Invention [Problem to be solved by the invention]

[0004] The TOF distance measurement method disclosed in Patent Document 1 measures the time of flight of light, and therefore can measure the absolute distance to an object, but the distance measurement accuracy is on the order of a few mm, making it difficult to measure distances with high accuracy.On the other hand, the measurement method using stripe pattern projection disclosed in Patent Document 2 has a relative distance measurement accuracy of a few μm to sub-mm, but cannot measure the absolute distance to an object, making it difficult to measure distances over a wide range.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a measuring device capable of measuring distances with high accuracy over a wide measurement range. [Means for solving the problem]

[0006] A measuring device according to one aspect of the present invention has a light source unit which emits measurement light having a predetermined light intensity distribution toward a measured object, an imaging unit which forms an image of the measurement light diffused or reflected by the measured object, and a calculation unit which performs calculations using output data from the imaging unit, wherein the imaging unit has a light detection unit which measures the light intensity distribution obtained by the measurement light, and the calculation unit calculates the distance to the measured object based on the flight time of light to the measured object and the light intensity distribution obtained by the measurement light.

[0007] Other objects and features of the present invention are illustrated in the following examples. Effect of the Invention

[0008] According to the present invention, it is possible to provide a measurement device capable of performing highly accurate distance measurement over a wide measurement range. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a configuration diagram of a measurement device in the first embodiment. [Diagram 2] FIG. 2 is a configuration diagram of a light source unit in the first embodiment. [Diagram 3] 4 is an example of a light intensity pattern in the first embodiment. [Figure 4] 1 is an explanatory diagram of the principle of distance measurement using a phase shift method; [Diagram 5] 5 is a flowchart showing a first processing procedure of distance measurement in the first embodiment. [Figure 6] 10 is a flowchart showing a second processing procedure of distance measurement in the first embodiment. [Figure 7] FIG. 11 is a configuration diagram of a light source unit in the second embodiment. [Figure 8] FIG. 11 is a configuration diagram of an imaging unit in a third embodiment. [Figure 9] FIG. 13 is a configuration diagram of a light source unit in the fourth embodiment. [Figure 10] FIG. 13 is a configuration diagram of a light source unit in the fifth embodiment. [Figure 11] FIG. 13 is a configuration diagram of a light detection unit in the fifth embodiment. [Figure 12] 23 is an example of a light intensity pattern in the sixth embodiment. [Figure 13] FIG. 13 is a configuration diagram of a measurement device in Example 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and duplicated descriptions will be omitted. EXAMPLES

[0011] First, a measuring device 10 in a first embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a configuration diagram of the measuring device 10. The measuring device 10 has a light source section 1, an imaging section 2, and a calculation section 3. The light source section 1 has a light source unit 11 and a projection means 12. The light source unit 11 emits light (image light). The projection means 12 projects the image light onto the measurement object. The imaging section 2 has an imaging means 13 and a light detection section 14. The projection means forms an image of the measurement light reflected or diffused from the measurement object on the light detection section 14. The calculation section 3 calculates the distance to the measurement object from the data measured by the light detection section 14. The light source section 1 (projection means 12) and the imaging section 2 are arranged so that the angle between the optical axis O1 and the optical axis O2 of the imaging section 2 is a predetermined angle θ. The light detection unit 14 is a photon-counting type imaging element having a plurality of pixels (a plurality of avalanche diodes arranged on a two-dimensional plane), and is also called a SPAD (Single Photon Avalanche Diode).

[0012] Next, the light source unit 11 of this embodiment will be described with reference to FIG. 2. FIG. 2 is a configuration diagram of the light source unit 11, showing an example of an optical arrangement. The light source unit 11 has a laser light source 21, a collimator lens 22, a TIR prism 23, and an image display element 24. The TIR prism 23 is composed of a first prism 23A and a second prism 23B, and is bonded with an air gap of several to several tens of μm formed at the interface between them. The image display element 24 is an element having micromirrors corresponding to pixels, and is a digital micromirror (DMD) type panel that modulates the illumination light by changing the reflection direction of the illumination light with the micromirrors.

[0013] The light beam emitted from the laser light source 21 is collimated by the collimator lens 22, and is totally reflected by the TIR prism 23, illuminating the image display element 24. The light beam modulated by the image display element 24 passes through the TIR prism 23 and is emitted from the light source unit 11. The light beam is modulated into a predetermined luminance pattern by the image display element 24. The laser light source 21 is assumed to be a laser light source with a wavelength of 1550 nm, but may be a laser or LED with wavelengths in the visible and infrared bands. The light source unit 11 may also be a light source in which a vertical cavity surface emitting laser or micro LEDs are arranged in a two-dimensional array.

[0014] Next, the light intensity pattern (light intensity distribution) projected (emitted) by the light source unit 1 will be described with reference to FIG. 3. FIG. 3 is an example of a light intensity pattern. In FIG. 3, the horizontal axis indicates the position x (a position normalized by 1 per period), and the vertical axis indicates the light intensity. The light intensity pattern shown in FIG. 3 is a light intensity pattern in which the light intensity varies sinusoidally along the x direction, and four types of sinusoidal patterns with the phase of the sinusoid shifted by 90° are projected in four frames. The light intensity of the four types of sinusoidal patterns projected on the object and the flight time from the image display element 24 to the light detection unit 14 are detected. According to the measurement method of this embodiment, the distance to the object can be measured more accurately based on the flight time of light and the light intensity (light intensity distribution).

[0015] Next, the principle of distance measurement using the phase shift method will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram of the principle of distance measurement using the phase shift method. The light intensities at positions (x, y) of four types of sine wave patterns are I0(x, y), I1(x, y), I2(x, y), and I3(x, y). In this case, when the four-step phase shift method is applied, the phase difference φ(x, y) of the sine wave pattern is expressed by the following formula (1).

[0016]

number

[0017] Since the phase difference φ(x,y) is proportional to x, it is possible to calculate the distance z to the object using the phase difference φ(x,y) and the angle θ. In shape measurement using stripe pattern projection, the shorter the distance of one period of the stripe pattern, the more the measurement accuracy can be improved. However, this method cannot determine n in equation (1), so it is not possible to measure the absolute distance to the object. Therefore, this embodiment makes it possible to measure the absolute distance by calculating n by finding the distance from the time of flight measured using a SPAD sensor.

[0018] Here, the distance in the x direction (predetermined direction) of one period (2π) of the sine wave pattern (light intensity pattern) at distance z is Δx, and the error (minimum value of measurement accuracy) of the distance z calculated from the time of flight is δ. In this case, it is preferable to set one period of the stripe pattern so as to satisfy the following conditional formula (2).

[0019] 1.0≦Δx / δtanθ≦20.0 …(2) If the upper or lower limit of condition (2) is exceeded, n cannot be determined to be a single value.

[0020] More preferably, the numerical range of conditional expression (2) is set as shown in the following conditional expression (2a).

[0021] 1.0≦Δx / δtanθ≦10.0 … (2a) If the upper limit of condition (2a) is exceeded, one period of the projection of the stripe pattern becomes longer, and the measurement accuracy decreases, which is undesirable.

[0022] More preferably, the numerical range of conditional expression (2) is set as in the following conditional expression (2b).

[0023] 1.0≦Δx / δtanθ≦5.0 … (2b) Hereinafter, the measurement method in this embodiment will be described in detail with respect to two processing procedures (a first processing procedure and a second processing procedure).

[0024] (First processing procedure) First, a first processing procedure for measuring the distance to the measurement object will be described with reference to Fig. 5. Fig. 5 is a flow chart showing the first processing procedure for measuring the distance. This processing procedure is started by an instruction from a user or a computer.

[0025] First, in step S501, the light source unit 1 projects a stripe pattern onto the object. Then, in step S502, the image capturing unit 2 captures the stripe pattern projected onto the object using the SPAD sensor of the light detecting unit 14. Then, in steps S503 and S505, the calculation unit 3 acquires the light intensity and the time of flight of each pixel from the output data of the light detecting unit 4 obtained by capturing the image. Then, in step S504, the calculation unit 3 calculates the phase difference φ' (0≦φ'≦2π) using the light intensity acquired in step S503. Then, in step S506, the calculation unit 3 calculates the distance z' (z-δ≦z'≦z+δ) to the object using the time of flight acquired in step S505. Then, in step S507, the calculation unit 3 calculates n in formula (1) using the phase difference φ' acquired in step S504 and the distance z' acquired in step S506. Next, in step S508, the calculation unit 3 calculates the distance z to the object by using the phase difference φ.

[0026] (Second processing procedure) Next, a second processing procedure for measuring the distance to the object to be measured will be described with reference to Fig. 6. Fig. 6 is a flow chart showing the second processing procedure for measuring the distance. This processing procedure is started by an instruction from a user or a computer. In Fig. 6, steps S601 to S606 are the same as steps S501 to S506 in Fig. 5, respectively, and therefore their description will be omitted.

[0027] In step S607, the calculation unit 3 calculates the structural information of the object (relative distance Δd from the reference surface of the object) using the phase difference φ′ acquired in step S604. Then, the calculation unit 3 adds or subtracts the relative distance Δd from the distance z′ acquired in step S606 to calculate the distance Z (Z=z′-Δd) to the reference surface of the object. Next, in step S608, the calculation unit 3 averages the distance Z by the number of measurement points of the object. For example, if the number of pixels of the object is 100 (10×10), the calculation unit 3 averages the distance Z by using 100 pieces of data. Next, in step S609, the calculation unit 3 calculates the distance z (z=Zave+Δd) by using the averaged distance Zave. It is known that the measurement accuracy is proportional to the square root of the number of data n, and when averaging is performed using data of 100×100 pixels, the measurement accuracy becomes approximately 1 / 100, which is an improvement of two orders of magnitude.

[0028] By using either or both of the first and second processing procedures, highly accurate and wide-range measurement becomes possible. In this embodiment, a method of projecting four types of sine wave patterns has been described, but three or more types of sine wave patterns may be projected to calculate the phase difference. Also, instead of a sine wave pattern, a predetermined periodic pattern such as a binary light and dark pattern may be projected. In other words, the predetermined light intensity distribution projected by the light source unit 1 may be a light intensity pattern in which the light intensity changes along a predetermined direction at a predetermined period.

[0029] The wavelength of the laser light source 21 may be in the visible light range, but is preferably in the infrared range so that it can be seen. If the wavelength of the laser light source 21 is λ (nm), it is preferable that the following conditional expression (3) is satisfied.

[0030] 700≦λ≦2000 …(3) If the lower limit of condition (3) is exceeded, the projected light becomes visible, which is undesirable, whereas if the upper limit of condition (3) is exceeded, the sensitivity of the SPAD decreases, which reduces the S / N ratio, which is undesirable.

[0031] More preferably, the numerical range of conditional expression (3) is set as in the following conditional expression (3a).

[0032] 750≦λ≦2000 …(3a) More preferably, the numerical range of conditional expression (3) is set as in the following conditional expression (3b).

[0033] 800≦λ≦1800 …(3b) In order to align the center of the projection plane (optical axis O1) with the center of the imaging plane (optical axis O2) at a predetermined distance, it is preferable that at least one of the light source unit 1 and the imaging unit 2 has a tilt mechanism that changes the angle θ. In addition, when performing measurements from short distances to long distances, it is preferable to perform measurements multiple times while changing the angle θ.

[0034] When the number of periods of the sine wave pattern on the projection plane at an angle θ is N(θ), it is preferable to change the frequency of the sine wave pattern so as to satisfy the following conditional expression (4).

[0035] N(θ+α) <N(θ)<N(θ―α) …(4) In conditional formula (4), α is a positive number smaller than the angle θ. As the angle θ becomes smaller, the distance traveled in the z direction during one period becomes longer, and the measurement accuracy decreases. For this reason, it is preferable to increase the number of periods so that the distance traveled in the z direction during one period is approximately equal.

[0036] In this embodiment, the projection means 12 is assumed to be a telecentric lens in which the projection size does not change with changes in distance. However, if a telecentric lens is used, the optical system of the projection means 12 will become larger. For this reason, it is preferable that the projection means 12 is non-telecentric in which the chief ray of the light beam at the outermost periphery illuminates the projection surface at a predetermined angle Ω (°). It is preferable that the predetermined angle Ω (°) satisfies the following conditional expression (5).

[0037] 0.5≦Ω≦25.0 …(5) If the lower limit of condition (5) is exceeded, the optical system of projection means 12 becomes large, which is not preferable. On the other hand, if the upper limit of condition (5) is exceeded, the size of the stripe pattern changes significantly depending on the distance, and the measurement accuracy changes significantly depending on the distance, which is also not preferable.

[0038] More preferably, the numerical range of conditional expression (5) is set as in the following conditional expression (5a).

[0039] 0.5≦Ω≦20.0 …(5a) More preferably, the numerical range of conditional expression (5) is set as in the following conditional expression (5b).

[0040] 1.5≦Ω≦15.0 …(5b) EXAMPLES

[0041] Next, a light source section 70 of a measuring device in a second embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a configuration diagram of the light source section 70. The light source section 70 has a light source unit for simultaneously projecting light intensity patterns of three colors with different wavelengths. The wavelengths of the laser light sources 71 (71A, 71B, 71C) are in the infrared band, and are 1310 nm, 1480 nm, and 1550 nm. Light with near-infrared wavelengths or red, green, and blue wavelengths in the visible band may also be used.

[0042] A light beam emitted from a first laser light source 71A having a wavelength of 1310 nm is collimated by a first collimator lens 72A, and is totally reflected by a TIR prism 73A to illuminate a first image display element 74A. The light beam (sine wave pattern A) modulated by the first image display element 74A is reflected by a cross dichroic prism 75 and emitted from the light source unit 70.

[0043] The light beam emitted from the second laser light source 71B having a wavelength of 1480 nm is collimated by the second collimator lens 72B, and is totally reflected by the TIR prism 73B to illuminate the second image display element 74B. The light beam (sine wave pattern B) modulated by the second image display element 74B passes through the cross dichroic prism 75 and is emitted from the light source unit 70.

[0044] The light beam emitted from the third laser light source 71C having a wavelength of 1550 nm is collimated by the third collimator lens 72C, and is totally reflected by the TIR prism 73C to illuminate the third image display element 74C. The light beam modulated by the third image display element 74C (sine wave pattern C) is reflected by the cross dichroic prism 75 and emitted from the light source unit 70.

[0045] The light beam emitted from the light source unit 70 has sine wave patterns A, B, and C that are sine waves with a phase difference of 120°. By applying the three-step phase shift method, it is possible to measure the phase difference φ equivalent to equation (1) in a single shot.

[0046] As described above, in this embodiment, the laser light source 71 has a first light source (one of 71A to 71C) and a second light source (the other one of 71A to 71C) having different peak wavelengths. The first light source projects a first light intensity pattern (one of the sine wave patterns A to C), and the second light source projects a second light intensity pattern (the other one of the sine wave patterns A to C) that is out of phase with the first light intensity pattern. EXAMPLES

[0047] Next, referring to FIG. 8, an imaging section 80 of a measuring device in a third embodiment of the present invention will be described. FIG. 8 is a configuration diagram of the imaging section 80. The imaging section 80 has an imaging means 81, a half mirror prism 82, a first optical detection section 83, and a second optical detection section 84. The first optical detection section 83 is a SPAD sensor. The second optical detection section 84 is an image sensor that measures only the light intensity of each pixel, such as a CMOS (Complementary Metal-Oxide-Semiconductor) sensor or a CCD (Charge Coupled Device) sensor. Diffused (reflected) light from the measurement object passes through the imaging means 81, is separated by the half mirror prism 82, and is imaged on the first optical detection section 83 and the second optical detection section 84.

[0048] The SPAD sensor is a photon counting sensor, so it can measure the time of flight with high accuracy even with a small amount of light. On the other hand, image sensors such as CMOS sensors have a lot of noise when the amount of light is below a certain level, and the measurement accuracy decreases. For this reason, when the transmittance of the half mirror prism 82 is TH (%) and the reflectance is RH (%), it is preferable to satisfy the following conditional formula (6).

[0049] 0.00 <TH / RH<0.50 …(6) More preferably, the numerical range of conditional expression (6) is set as in the following conditional expression (6a).

[0050] 0.00 <TH / RH<0.40 …(6a) More preferably, the numerical range of conditional expression (6) is set as in the following conditional expression (6b).

[0051] 0.00 <TH / RH<0.25 …(6b) In this embodiment, the SPAD sensor is disposed on the transmission side of the half mirror prism 82, but this is not limiting, and the SPAD sensor may be disposed on the reflection side. EXAMPLES

[0052] Next, a light source unit 90 of a measuring device in a fourth embodiment of the present invention will be described with reference to Fig. 9. Fig. 9 is a configuration diagram of the light source unit 90. The light source unit 90 has a laser light source 91, a collimator lens 92, a polarizing beam splitter 93, a reflective liquid crystal panel (image display element) 94, and a projection means 95. A P-polarized light beam emitted from the laser light source 91 is collimated by the collimator lens 92, transmitted by the polarizing beam splitter 93, and illuminates the reflective liquid crystal panel 94. The light modulated by the reflective liquid crystal panel 94 (S-polarized light) is reflected by the polarizing beam splitter 93 and projected onto the measurement object via the projection means 95.

[0053] In this embodiment, a reflective liquid crystal panel 94 is used as the image display element, but this is not limited to this and a transmissive liquid crystal panel may be used instead of the reflective liquid crystal panel 94. The polarizing beam splitter 93 is generally made of a multi-layer dielectric film, but this is not limited to this and, for example, a wire grid type polarizing beam splitter may be used. EXAMPLES

[0054] Next, the light source unit 100 and the imaging unit (light detection unit 110) of the imaging device according to the fifth embodiment of the present invention will be described with reference to FIGS. 10(a), (b) and 11(a), (b).

[0055] 10(a) is a configuration diagram of the light source unit 100. The light source unit 100 has a laser light source 101, a collimator lens 102, a TIR prism 103, a DMD type image display element 104, a polarizing plate 105, a first phase plate 106, a transmissive liquid crystal panel 107, a second phase plate 108, and a projection means 109.

[0056] A light beam emitted from laser light source 101 is collimated by collimator lens 102, and is totally reflected by TIR prism 103, illuminating image display element 104. The light beam modulated by image display element 104 passes through TIR prism 103, has its polarization aligned in a predetermined direction (u direction) by polarizing plate 105, and is converted into circularly polarized light by first phase plate 106. A phase difference is imparted by transmissive liquid crystal panel 107 so that the phase difference becomes large along the v direction, and a polarization pattern is generated in which the direction of linear polarization changes along the v direction by passing through a second phase plate.

[0057] Fig. 10(b) is a schematic diagram of a polarization pattern (one period). In reality, the polarization direction changes more smoothly to form a polarization pattern of several periods. The light beam having this polarization pattern is projected onto the measurement object via the projection means 109.

[0058] Fig. 11(a) is a configuration diagram of the photodetector 110 of the imaging unit 2. The photodetector 110 has a SPAD 111 and a polarizer array 112. The polarizer array 112 has polarizers with polarization axes of 0°, 45°, 90°, and 135° corresponding to each pixel. Fig. 11(b) is a schematic diagram of the polarizer array 112. As the polarizer of the polarizer array 112, a wire grid polarizer or a polarizer using a photonics crystal is generally used.

[0059] Diffused (reflected) light from the object to be measured passes through the imaging means, polarizer array 112, and is imaged on the SPAD 111. By projecting the above-mentioned polarization pattern, four sinusoidal patterns with phases shifted by 90° each can be obtained from data for four types of polarization axes of 0°, 45°, 90°, and 135°. Therefore, by applying the four-step phase shift method, it is possible to calculate the phase difference φ equivalent to that of equation (1) in a single shot. EXAMPLES

[0060] Next, a light intensity pattern (light intensity distribution) in Example 6 of the present invention will be described with reference to Figures 12(a) and (b). In this example, a phase difference in the time direction is used to measure the time of flight. The optical arrangement of the measurement device in this example is the same as that of the measurement device 10 in Figure 1.

[0061] Fig. 12(a) is an example of a light intensity pattern, showing the change in light intensity over time. In Fig. 12(a), the horizontal axis shows time (number of frames) and the vertical axis shows light intensity (light intensity normalized by peak intensity). For example, in the case of 50 frames, the time for one frame is 0.02 seconds.

[0062] Figure 12(b) shows the peak light intensity distribution in the x direction for each frame. In Figure 12(b), the horizontal axis shows the position x (position normalized by 1 period), and the vertical axis shows the peak light intensity. In other words, by projecting a light beam whose light intensity changes not only in the position direction but also in the time direction, it is possible to measure the time of flight from the phase difference of the light intensity distribution in the time direction. In addition, by applying the four-step phase shift method from the change in light intensity in the position direction, it is possible to calculate the phase difference φ in equation (1).

[0063] When the maximum value of the peak light intensity in the time direction is PH and the minimum value is PL, it is preferable to satisfy the following conditional expression (7).

[0064] 0.05≦PL / PH≦0.90 …(7) If the lower limit of condition (7) is exceeded, the light intensity detected by the SPAD sensor decreases, and the accuracy of measuring the time of flight from the phase difference of the light intensity in the time direction decreases. On the other hand, if the upper limit of condition (7) is exceeded, the change in light intensity in the position direction decreases, and the accuracy of the phase difference φ decreases.

[0065] More preferably, the numerical range of conditional expression (7) is set as in the following conditional expression (7a).

[0066] 0.10≦PL / PH≦0.80 …(7a) More preferably, the numerical range of conditional expression (7) is set as in the following conditional expression (7b).

[0067] 0.15≦PL / PH≦0.60 …(7b) EXAMPLES

[0068] Next, a measuring device 130 according to a seventh embodiment of the present invention will be described with reference to Figs. 13(a) and (b). Fig. 13(a) is a configuration diagram of the measuring device 130. The measuring device 130 has a light source section 131 and an imaging section 132. Fig. 13(b) is a configuration diagram of the light source section 131. The light source section 131 has a light source unit 133 and a projection means 134.

[0069] The optical axis O1 is the optical axis of the light source unit 133. The optical axis O2 is the optical axis of the projection means 134. The optical axis O3 is the optical axis of the imaging section 132. The projection means 134 has a mechanism for tilting with respect to the light source unit 133, and the light source section 131 has a mechanism for tilting with respect to the optical axis O3. The optical axes O1a and O1b each indicate the optical axis when the light source section 131 is tilted by a predetermined angle. The optical axis O2a and optical axis O2b each indicate the optical axis when the projection means 134 is tilted by a predetermined angle.

[0070] In the first embodiment, it has been described that it is preferable to provide a tilt mechanism for changing the angle θ in at least one of the light source unit 1 and the imaging unit 2 in order to align the center of the projection surface (optical axis O1) and the center of the imaging surface (optical axis O2) at a predetermined distance. However, when the light source unit 131 is tilted, the image projected onto the measurement object is tilted. For this reason, in this embodiment, when the light source unit 131 is tilted, it is preferable to tilt the projection means 134 and correct the tilt of the projected image based on the Scheimpflug principle.

[0071] (Other Examples) The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-mentioned embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0072] According to each embodiment, it is possible to provide a measurement device, a measurement method, and a program capable of measuring distances with high accuracy in a wide measurement range.

[0073] The disclosure of each embodiment includes the following configurations and methods. (Configuration 1) a light source unit that emits measurement light having a predetermined light intensity distribution toward the measurement object; an imaging unit that forms an image of the measurement light that is diffused or reflected by the measurement object; A calculation unit that performs a calculation using output data from the imaging unit, the imaging unit has a light detection unit that measures a light intensity distribution obtained by the measurement light, The measuring device according to claim 1, wherein the calculation unit calculates a distance to the object based on a time of flight of light to the object and a light intensity distribution obtained by the measurement light. (Configuration 2) 2. The measuring device according to configuration 1, wherein the light detection section has a plurality of avalanche diodes arranged on a two-dimensional plane. (Configuration 3) 3. The measuring device according to configuration 1 or 2, wherein the predetermined light intensity distribution is a light intensity pattern in which the light intensity changes along a predetermined direction at a predetermined period. (Configuration 4) Let δ be the minimum value of the measurement accuracy of the distance to the object calculated from the time of flight, Δx be the distance of one period of the light intensity pattern at the distance to the object in the predetermined direction, and θ (°) be the angle between the optical axis of the light source unit and the optical axis of the imaging unit. 1.0≦Δx / δtanθ≦20.0 4. The measuring apparatus according to any one of configurations 1 to 3, wherein the following conditional expression is satisfied: (Configuration 5) The light source unit includes: The image display device includes an image display element and a light source. 5. The measuring device according to any one of configurations 1 to 4, wherein light from the light source is illuminated onto the image display element, and the light modulated by the image display element is emitted. (Configuration 6) 6. The measuring device according to any one of configurations 1 to 5, wherein the light source unit emits light having a plurality of light intensity patterns with different phases as the light of the predetermined light intensity distribution. (Configuration 7) the light source unit includes a first light source and a second light source having different peak wavelengths; The measurement device according to configuration 6, characterized in that, as the light having the predetermined light intensity distribution, the first light source projects a first light intensity pattern, and the second light source emits a second light intensity pattern having a phase different from that of the first light intensity pattern. (Configuration 8) 8. The measuring device according to any one of configurations 1 to 7, wherein the calculation unit calculates the distance to the object by a phase shift method. (Configuration 9) the light source unit emits three or more types of periodic patterns as the light having the predetermined light intensity distribution, The measuring device according to any one of configurations 1 to 8, wherein the calculation unit calculates the distance to the object by using a phase difference obtained by projecting the periodic pattern and an angle between an optical axis of the light source unit and an optical axis of the imaging unit. (Method 1) an emission step of emitting measurement light having a predetermined light intensity distribution to the measurement object; an imaging step of forming an image on an imaging unit using the measurement light diffused or reflected by the measurement object; A calculation step of performing a calculation using output data from the imaging unit, In the imaging step, a light intensity distribution obtained by the measurement light is measured; A measuring method comprising: calculating, in the calculating step, a distance to the measurement object based on a time of flight of light to the measurement object and a light intensity distribution obtained by the measurement light. (Configuration 10) A program for causing a computer to execute the measurement method according to Method 1.

[0074] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0075] 1 Light source section 2. Imaging unit 3 Arithmetic section 10. Measuring Equipment 14 Light detection section

Claims

1. a light source unit that emits measurement light having a predetermined light intensity distribution toward the measurement object; an imaging unit that forms an image of the measurement light that is diffused or reflected by the measurement object; A calculation unit that performs a calculation using output data from the imaging unit, the imaging unit has a light detection unit that measures a light intensity distribution obtained by the measurement light, The measuring device according to claim 1, wherein the calculation unit calculates a distance to the object based on a time of flight of light to the object and a light intensity distribution obtained by the measurement light.

2. 2. The measuring device according to claim 1, wherein the light detection section includes a plurality of avalanche diodes arranged on a two-dimensional plane.

3. 3. The measuring apparatus according to claim 1, wherein the predetermined light intensity distribution is a light intensity pattern in which the light intensity changes along a predetermined direction at a predetermined period.

4. where δ is the minimum value of the measurement accuracy of the distance to the object calculated from the time of flight, Δx is the distance of one period of the light intensity pattern at the distance to the object in the predetermined direction, and θ (°) is the angle between the optical axis of the light source unit and the optical axis of the imaging unit. 1.0≦Δx / δtanθ≦20.0 3. The measuring apparatus according to claim 1, wherein the following condition is satisfied:

5. The light source unit includes: The image display device includes an image display element and a light source.

3. The measuring apparatus according to claim 1, wherein the light from the light source is illuminated onto the image display element, and the light modulated by the image display element is emitted.

6. 3. The measuring device according to claim 1, wherein the light source unit emits light having a plurality of light intensity patterns with different phases as the light having the predetermined light intensity distribution.

7. the light source unit includes a first light source and a second light source having different peak wavelengths; The measurement device according to claim 6, characterized in that, as the light having the predetermined light intensity distribution, the first light source projects a first light intensity pattern, and the second light source emits a second light intensity pattern having a phase different from that of the first light intensity pattern.

8. 3. The measuring device according to claim 1, wherein the calculation unit calculates the distance to the object by a phase shift method.

9. the light source unit emits three or more types of periodic patterns as the light having the predetermined light intensity distribution, The measuring device according to claim 1 or 2, characterized in that the calculation unit calculates the distance to the object using a phase difference obtained by projecting the periodic pattern and an angle between an optical axis of the light source unit and an optical axis of the imaging unit.

10. an emission step of emitting measurement light having a predetermined light intensity distribution to the measurement object; an imaging step of forming an image on an imaging unit using the measurement light diffused or reflected by the measurement object; A calculation step of performing a calculation using output data from the imaging unit, In the imaging step, a light intensity distribution obtained by the measurement light is measured; A measuring method comprising: calculating, in the calculating step, a distance to the measurement object based on a time of flight of light to the measurement object and a light intensity distribution obtained by the measurement light.

11. A program for causing a computer to execute the measurement method according to claim 10.

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