JP2020148646A - Phase determination method and measuring device - Google Patents

Abstract

To provide a technology that can reduce the number of times of image projection in a phase shift method.SOLUTION: A phase determination method includes: projecting, on an object of measurement, a plurality of first images that indicate two or more cycles of a luminance pattern changing in accordance with a sine wave having a first wavelength and are different in phase from each other; projecting, on the object of measurement, a plurality of second images that indicate a luminance pattern changing in accordance with a sine wave having a second wavelength longer than the first wavelength and are different in phase from each other; creating a first imaging data of the object of measurement in a projection state of the first images; creating second imaging data of the object of measurement in the projection state of the second images; determining, based on the first imaging data, first candidates for the phase of a portion of projection on a measurement position of the object of measurement in a first pattern of any one of the first images; determining, based on the first and second imaging data, second candidates for the phase of a portion of projection on a measurement position in a second pattern of any one of the second images; and specifying the phase of the first pattern at the portion of projection on the measurement position from the first candidates by using the second candidates. The number of the second images is smaller than the number of the first images.SELECTED DRAWING: Figure 10

Description

The present invention relates to a phase determination method and a measuring device.

The phase shift method is known as a method for measuring the three-dimensional shape of the object to be measured. In the phase shift method, first, the projection device individually projects three or more images in which the phases of the sine waves are different from each other, showing a pattern of brightness that changes according to the sine wave in a predetermined direction. Next, the imaging device generates imaging data by imaging the object to be measured each time the image is projected onto the object to be measured. Next, the arithmetic unit identifies the projected portion projected at the measurement position of the object to be measured among the reference patterns which are any of the three patterns based on the imaging data. The arithmetic unit identifies the projection portion by calculating the phase of the reference pattern indicating the projection portion. The arithmetic unit calculates the distance to the measurement position based on the phase of the reference pattern indicating the projection portion. The arithmetic unit repeats the above operation while changing the measurement position to measure the three-dimensional shape of the object to be measured.

Patent Document 1 describes a technique capable of improving the accuracy of phase calculation in the phase shift method. In the technique described in Patent Document 1, a phase candidate indicating a projected portion of the first pattern to the measurement position is calculated using a first pattern in which the brightness changes in a predetermined direction according to a reference sine wave, and further, a reference. Using the second pattern in which the brightness changes in a predetermined direction according to the sine wave having a wavelength longer than that of the sine wave, a phase candidate indicating the projected portion to the measurement position of the second pattern is calculated. Then, the phase of the projection portion in the first pattern is determined based on these phase candidates.

JP-A-2009-115612

In the phase shift method using a plurality of sine waves having different wavelengths as described in Patent Document 1, the number of projections of an image showing a pattern corresponding to a sine wave having a long wavelength is short among a plurality of sine waves. Since the number of times the image showing the pattern corresponding to the sine wave is projected is the same, there is a problem that it takes time to project the image.

One aspect of the phase determination method according to the present invention is the phase determination method executed by the measuring device, which shows a pattern in which the brightness changes according to the sine wave of the first wavelength in the first direction for two cycles or more. A plurality of first images having different phases of the sine waves of the first wavelength are individually projected onto the object to be measured, and the brightness is adjusted to match the sine waves of the second wavelength longer than the first wavelength in the second direction. Shows a changing pattern, and a plurality of second images having different phases of the sinusoidal waves of the second wavelength are individually projected onto the object to be measured, and the plurality of first images are individually projected onto the object to be measured. The first imaging data is generated by imaging the object to be measured in the projected first situation, and the object to be measured is subjected to the second situation in which the plurality of second images are individually projected onto the object to be measured. The second imaging data is generated by imaging, and the phase candidate of the projection portion to the measurement position of the object to be measured in the first pattern, which is the pattern shown in any of the plurality of first images, is selected as the first pattern. The first imaging data and the second image are used to determine the phase candidates of the projection portion to the measurement position in the second pattern, which is a pattern shown in any of the plurality of second images, which is determined based on the first imaging data. Determined based on the imaging data, the phase of the first pattern in the projection portion to the measurement position is specified from the phase candidates of the first pattern by using the phase candidates of the second pattern. , The number of the plurality of second images is smaller than the number of the plurality of first images.

One aspect of the measuring device according to the present invention shows a pattern in which the brightness changes according to the sine wave of the first wavelength for two cycles or more in the first direction, and the phases of the sine waves of the first wavelength are different from each other. The first image of the above is individually projected onto the object to be measured, and in the second direction, a pattern in which the brightness changes according to the sine wave of the second wavelength longer than the first wavelength is shown, and the sine of the second wavelength is shown. A projection unit that individually projects a plurality of second images having different wave phases onto the object to be measured, a camera that captures the object to be measured, and the plurality of first images individually on the object to be measured. The subject in the first pattern, which is a pattern shown in any of the plurality of first images, based on the first imaging data generated by the camera imaging the object to be measured in the projected first situation. In the first determination unit that determines the phase candidate of the projection portion to the measurement position of the measurement object and the second situation in which the plurality of second images are individually projected onto the measurement object, the camera performs the measurement object. The projection portion to the measurement position in the second pattern, which is the pattern shown in any of the plurality of second images, based on the second imaging data generated by imaging the image and the first imaging data. The phase of the first pattern in the projection portion to the measurement position is determined by the second determination unit that determines the phase candidate of the second pattern, and the phase candidate of the first pattern is selected by using the phase candidate of the second pattern. The number of the plurality of second images including the phase specifying portion specified from the inside is smaller than the number of the plurality of first images.

It is a figure which shows the measuring apparatus 100 which concerns on 1st Embodiment. It is a figure which shows an example of the liquid crystal light bulb 12. It is a figure for demonstrating the 1st projection image G1. It is a figure for demonstrating the 5th projection image G5. It is a figure which shows an example of the image sensor 22. It is a figure for demonstrating the 1st candidate φ. It is a figure for demonstrating the 2nd candidate θ. It is a figure which shows an example of an information processing apparatus 3. It is a figure for demonstrating the calculation method of the distance to a measurement position. It is a flowchart for demonstrating the operation of the measuring apparatus 100. It is a figure for demonstrating the 2nd wavelength image Ga20 in the 1st modification. It is a figure for demonstrating the 1st wavelength image Ga10 in the 2nd modification. It is a drawing which shows an example of the 1st projection image G1 to the 12th projection image G12.

A: First Embodiment A1: Outline of the measuring device 100 FIG. 1 is a diagram showing a measuring device 100 according to the first embodiment. The measuring device 100 measures the three-dimensional shape of the object to be measured 200 by using the phase shift method. The measuring device 100 includes a projection unit 1, a camera 2, and an information processing device 3. The projection unit 1 and the camera 2 are arranged in a direction along the X1 direction.

The projection unit 1 is, for example, a projector. The projection unit 1 includes a light source 11, a liquid crystal light bulb 12, and a projection optical system 13.

The light source 11 is an LED (Light Emitting Diode). The light source 11 is not limited to the LED, and may be, for example, a xenon lamp, an ultrahigh pressure mercury lamp, a laser light source, or the like.

The liquid crystal light bulb 12 is composed of a liquid crystal panel or the like in which liquid crystal exists between a pair of transparent substrates. As illustrated in FIG. 2, the liquid crystal light bulb 12 has a rectangular pixel region 12a including a plurality of pixels 12p located in a matrix.

An X1-Y1 coordinate system is set in the liquid crystal light bulb 12. The X1 direction is the horizontal direction of the liquid crystal light bulb 12, and more specifically, the lateral direction of the liquid crystal light bulb 12. The Y1 direction intersects the X1 direction. The Y1 direction is, for example, a direction orthogonal to the X1 direction. The Y1 direction is typically the vertical direction of the liquid crystal light bulb 12, more specifically the vertical direction of the liquid crystal light bulb 12.

Each of the plurality of pixels 12p is identified by the coordinates of the X1-Y1 coordinate system. For example, in FIG. 2, the pixel 12p located in the upper left corner of the pixel region 12a is identified by the coordinates (1, 1) in the X1-Y1 coordinate system.

In the liquid crystal light bulb 12, a drive voltage corresponding to the image data is applied to the liquid crystal for each pixel 12p. The pixel 12p is set to a light transmittance based on the drive voltage. The light emitted from the light source 11 is modulated by passing through the pixel region 12a and heads toward the projection optical system 13. The liquid crystal light bulb 12 is an example of an optical modulation device.

The projection optical system 13 projects light modulated by the liquid crystal light bulb 12, that is, an image onto the object to be measured 200.

The projection unit 1 individually projects the first projection image G1, the second projection image G2, the third projection image G3, and the fourth projection image G4 onto the object to be measured 200. That is, the projection unit 1 does not simultaneously project the first projection image G1, the second projection image G2, the third projection image G3, and the fourth projection image G4 onto the object to be measured 200, but projects each of them. The timing is shifted and the images are projected in order. The order of projection of the first projection image G1 to the fourth projection image G4 may be the order of the first projection image G1, the second projection image G2, the third projection image G3, the fourth projection image G4, or any other order. Good. Hereinafter, when it is not necessary to distinguish the first projected images G1 to the fourth projected images G4 from each other, these are referred to as "first wavelength image Ga10".

The first wavelength image Ga10 is generated by the liquid crystal light bulb 12. Therefore, the X1 direction is also the horizontal direction of the first wavelength image Ga10, in other words, the horizontal direction. The X1 direction is an example of the first direction. The first direction is not limited to the X1 direction.

The first wavelength image Ga10 shows a pattern of luminance that changes in the X1 direction. Specifically, in the pattern shown by the first wavelength image Ga10, as illustrated in FIG. 3, the brightness A changes in the X1 direction in accordance with the sine wave W11 having the first predetermined wavelength λ1. The first predetermined wavelength λ1 is an example of the first wavelength.

The sine wave W11 having the first predetermined wavelength λ1 shown in FIG. 3 is a sine wave whose phase is adjusted so as to be a cosine wave. Note that FIG. 3 shows a first projected image G1 which is an example of the first wavelength image Ga10. The first wavelength image Ga10 has a striped pattern corresponding to the first predetermined wavelength λ1.

The first wavelength image Ga10 shows a pattern that changes in the X1 direction for four cycles according to the amplitude of the sine wave of the first predetermined wavelength λ1. The pattern shown in the first wavelength image Ga10 is not limited to four cycles, and may be two or more cycles.

FIG. 3 further shows the relationship between the position in the X1 direction in the pattern shown by the first projected image G1 and the phase P of the sine wave having the first predetermined wavelength λ1. Since the first projected image G1 shows a pattern for four cycles, the change of the phase P from 0 to 2π is repeated four times in the X1 direction.

As illustrated in FIG. 1, in the patterns shown in each of the first projected image G1 to the fourth projected image G4, the phases of the sine waves having the first predetermined wavelength λ1 are different from each other. Hereinafter, a sine wave having a first predetermined wavelength λ1 will be referred to as a “first sine wave”.

The phase of the first sine wave in the pattern shown by the second projected image G2 is delayed by π / 2 from the phase of the first sine wave in the pattern shown by the first projected image G1. The phase of the first sine wave in the pattern shown by the third projected image G3 is delayed by π / 2 from the phase of the first sine wave in the pattern shown by the second projected image G2. The phase of the first sine wave in the pattern shown by the fourth projected image G4 is delayed by π / 2 from the phase of the first sine wave in the pattern shown by the third projected image G3. The first projected image G1 to the fourth projected image G4 are examples of a plurality of first images. The pattern shown by the first projected image G1 is an example of the first pattern.

The projection unit 1 further projects the fifth projection image G5 and the sixth projection image G6 individually on the object to be measured 200. That is, the projection unit 1 does not simultaneously project the fifth projection image G5 and the sixth projection image G6 onto the object to be measured 200, but instead projects the fifth projection image G5 and the sixth projection image G6 in order by shifting the projection timing of each. The order of projection of the fifth projected image G5 to the sixth projected image G6 may be the order of the fifth projected image G5 and the sixth projected image G6, or may be another order. The projection unit 1 may project the fifth projection image G5 to the sixth projection image G6 after projecting the first projection image G1 to the fourth projection image G4, or the first projection image G1 to the fourth projection image. Before projecting G4, the fifth projected image G5 to the sixth projected image G6 may be projected. Hereinafter, when it is not necessary to distinguish the fifth projected image G5 and the sixth projected image G6 from each other, these are referred to as "second wavelength image Ga20".

The second wavelength image Ga20 is generated by the liquid crystal light bulb 12 in the same manner as the first wavelength image Ga10. Therefore, the X1 direction is also the horizontal direction of the second wavelength image Ga20, in other words, the horizontal direction. The X1 direction is also an example of the second direction.

The second wavelength image Ga20 shows a pattern of luminance that changes in the X1 direction. Specifically, as illustrated in FIG. 4, the pattern shown by the second wavelength image Ga20 has a brightness A in the X1 direction in accordance with a sine wave W21 having a second predetermined wavelength λ2 longer than the first predetermined wavelength λ1. Change. The second predetermined wavelength λ2 is an example of the second wavelength.

The sine wave W21 having the second predetermined wavelength λ2 shown in FIG. 4 is a sine wave whose phase is adjusted so as to be a cosine wave. Note that FIG. 4 shows a fifth projected image G5, which is an example of the second wavelength image Ga20. The second predetermined wavelength λ2 is four times as long as the first predetermined wavelength λ1. The second predetermined wavelength λ2 may be at least twice as long as the first predetermined wavelength λ1. The second wavelength image Ga20 has a striped pattern corresponding to the second predetermined wavelength λ2.

The second wavelength image Ga20 shows a pattern that changes in the X1 direction according to the amplitude of the sine wave of the second predetermined wavelength λ2 for one cycle. The length of the second wavelength image Ga20 in the X1 direction is equal to the length of the first wavelength image Ga10 in the X1 direction.

FIG. 4 further shows the relationship between the position in the X1 direction in the pattern shown by the fifth projected image G5 and the phase P of the sine wave having the second predetermined wavelength λ2. Since the fifth projected image G5 shows a pattern for one cycle, the phase P changes from 0 to 2π only once in the X1 direction.

As illustrated in FIG. 1, in the patterns shown in each of the fifth projected image G5 and the sixth projected image G6, the phases of the sine waves having the second predetermined wavelength λ2 are different from each other. Hereinafter, a sine wave having a second predetermined wavelength λ2 will be referred to as a “second sine wave”.

The phase of the second sine wave in the pattern shown by the sixth projected image G6 is delayed by π / 2 from the phase of the second sine wave in the pattern shown by the fifth projected image G5. The fifth projected image G5 to the sixth projected image G6 are examples of a plurality of second images having a smaller number than the plurality of first images. The pattern shown in the fifth projected image G5 is an example of the second pattern.

The camera 2 includes a light receiving optical system 21 such as a lens, and an image sensor 22 that converts the light collected by the light receiving optical system 21 into an electric signal. The image sensor 22 is a CCD (Charge Coupled Device) image sensor. The image sensor 22 is not limited to the CCD image sensor, and may be, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor. As illustrated in FIG. 5, the image pickup device 22 has a rectangular image pickup region 22a including a plurality of light receiving cells 22p located in a matrix.

An X2-Y2 coordinate system is set in the image sensor 22. The X2 direction is the horizontal direction of the image sensor 22, and more specifically, the lateral direction of the image sensor 22. The Y2 direction intersects the X2 direction. The Y2 direction is, for example, a direction orthogonal to the X2 direction. The Y2 direction is typically the horizontal direction of the image sensor 22, and more specifically, the lateral direction of the image sensor 22.

The X2 direction does not intersect the X1 direction, and the Y2 direction does not intersect the Y1 direction. The X2 direction may intersect the X1 direction, and the Y2 direction may intersect the Y1 direction. The distance from the projection optical system 13 to the liquid crystal light bulb 12 is equal to the distance from the light receiving optical system 21 to the image sensor 22.

Each of the plurality of cells 22p is identified by the coordinates of the X2-Y2 coordinate system. For example, in FIG. 5, the cell 22p located in the upper left corner of the imaging region 22a is identified by the coordinates (1, 1) in the X2-Y2 coordinate system.

The camera 2 generates imaging data by imaging the object 200 to be measured. For example, the camera 2 uses the image sensor 22 to image the object to be measured 200 in the first situation in which each of the first projected images G1 to the fourth projected image G4 is individually projected onto the object to be measured 200.

The image sensor 22 generates the first captured image data by imaging the measured object 200 in a situation where the first projected image G1 is projected onto the measured object 200. The image sensor 22 generates the second captured image data by imaging the measured object 200 in a situation where the second projected image G2 is projected onto the measured object 200. The image sensor 22 generates the third captured image data by imaging the measured object 200 in a situation where the third projected image G3 is projected onto the measured object 200. The image sensor 22 generates the fourth captured image data by imaging the measured object 200 in a situation where the fourth projected image G4 is projected onto the measured object 200. Each of the first captured image data to the fourth captured image data is an example of the first captured image data.

Further, the camera 2 takes an image of the object to be measured 200 by the image sensor 22 in the second situation where each of the fifth projected image G5 to the sixth projected image G6 is individually projected onto the object to be measured 200.

The image sensor 22 generates the fifth captured image data by imaging the measured object 200 in a situation where the fifth projected image G5 is projected onto the measured object 200. The image sensor 22 generates the sixth captured image data by imaging the measured object 200 in a situation where the sixth projected image G6 is projected onto the measured object 200. Each of the fifth captured image data to the sixth captured image data is an example of the second captured image data.

The information processing device 3 is, for example, a PC (Personal Computer). The information processing device 3 is not limited to a PC, and may be, for example, a dedicated computer. The information processing device 3 identifies the three-dimensional shape of the object to be measured 200 based on the first captured image data to the sixth captured image data. Specifically, the information processing apparatus 3 uses the phase shift method to specify the three-dimensional shape of the object to be measured 200.

A2: Outline of the phase shift method Here, the outline of the phase shift method will be described. Brightness p ₁ in the toward direction X1 pattern indicated by the first projected image G1 is represented by Formula 1, the luminance p ₂ of toward the X1 direction of the pattern indicated by the second projected image G2 is represented by Formula 2, 3 brightness p ₃ of toward the X1 direction of the pattern indicated by the projection image G3 is expressed by equation 3, the luminance p ₄ of toward the X1 direction of the pattern indicated by the fourth projected image G4 is to be represented by the formula 4. The cosine wave represented by the equations 1 to 4 can be replaced with a sine wave whose phase is adjusted with respect to the cosine wave.
p ₁ = A · cos (kx) ・ ・ ・ Equation 1
p ₂ = A · cos (kx− (π / 2)) ・ ・ ・ Equation 2
p ₃ = A · cos (kx−π) ・ ・ ・ Equation 3
p ₄ = A · cos (kx− (3π / 2)) ・ ・ ・ Equation 4
In Equations 1 to 4, A indicates the amplitude of the brightness of each pattern of the first projected image G1 to the fourth projected image G4. k is a constant that determines the first predetermined wavelength λ1. x indicates the coordinates of the first projected image G1 to the fourth projected image G4 in the X1 direction. For example, x indicates the coordinates of the pixel 12p of the liquid crystal light bulb 12 shown in FIG. 2 in the X1 direction.

The image of the object to be measured 200 is imaged by a plurality of cells 22p in the imaging region 22a. Therefore, each of the plurality of cells 22p images images of measurement positions different from each other in the object to be measured 200. For example, the brightness value observed by the cell 22p at arbitrary coordinates (x0, y0) indicates the brightness of the measurement position imaged by the cell 22p at coordinates (x0, y0) in the object 200 to be measured.

In a situation where the first projected image G1 to the fourth projected image G4 are individually projected onto the object to be measured 200, the brightness value I observed by the cell 22p at the coordinates (x0, y0) in the image sensor 22 is determined.
I ₁ = {A ・ cos (φ) + G} × R ・ ・ ・ Equation 5
I ₂ = {A · cos (φ− (π / 2)) + G} × R ・ ・ ・ Equation 6
I ₃ = {A · cos (φ−π) + G} × R ・ ・ ・ Equation 7
I ₄ = {A · cos (φ− (3π / 2)) + G} × R ・ ・ ・ Equation 8
Will be.
In Equations 5 to 8, φ is a candidate for the phase of the projected portion to the measurement position imaged by the cell 22p of the coordinates (x0, y0) in the pattern shown by the first projected image G1 shown in FIG. .. G is a global ambient light component such as ambient light that has nothing to do with the projection of an image showing a pattern. R is the reflectance of the measurement position of the object to be measured 200, and has nothing to do with the projection of the image showing the pattern.

The luminance value I ₁ is a luminance value observed by the cell 22p of the coordinates (x0, y0) in the situation where the first projected image G1 is projected. The luminance value I ₂ is a luminance value observed by the cell 22p of the coordinates (x0, y0) in the situation where the second projected image G2 is projected. The brightness value I ₃ is a brightness value observed by the cell 22p of the coordinates (x0, y0) in the situation where the third projected image G3 is projected. The luminance value I ₄ is a luminance value observed by the cell 22p of the coordinates (x0, y0) in the situation where the fourth projected image G4 is projected.

The phase candidate φ is calculated by Equation 9 derived from Equations 5 to 8.
φ = tan ^-1 {(I _2- I ₄ ) / (I _1- I ₃ )} ・ ・ ・ Equation 9

Here, as illustrated in FIG. 3, since the first projected image G1 shows a pattern for four cycles, the change of the phase P from 0 to 2π in the X1 direction is repeated four times. Therefore, there are a total of four phase candidate φs specified by Equation 9 as illustrated by the black circles in FIG. Specifically, there are four phase candidates φ, a phase candidate φ + 2π, a phase candidate φ + 4π, and a phase candidate φ + 6π. Therefore, in the pixel region 12a, there are four corresponding parts in the X1 direction corresponding to the phase candidate φ, specifically, the corresponding parts X11 to X14.

On the other hand, for example, when each of the first projected image G1 to the fourth projected image G4 shows a pattern for one cycle of the second sine wave as shown in FIG. 7, the number of phase candidates θ is one. Therefore, in the pixel region 12a, only one corresponding portion in the X1 direction corresponding to the phase candidate θ, specifically, one corresponding portion X21 is specified. The phase candidate θ is a phase candidate of the projection portion to the measurement position imaged by the cell 22p of the coordinates (x0, y0) in the pattern shown in FIG. 7.

Here, the longer the wavelength of the sine wave that determines the interval between the striped patterns of the pattern, the greater the influence of the noise contained in the luminance values I ₁ to I ₄ in identifying the corresponding portion. For example, in FIGS. 6 and 7, when the influence of noise on the phase candidate is both NW, the influence of noise on the corresponding portion X21 shown in FIG. 7 NW2 is the influence of noise on the corresponding portion X12 shown in FIG. It will be larger than NW1.

Therefore, the measuring device 100 determines the phase candidate φ by using the first projected image G1 to the fourth projected image G4. Further, the measuring device 100 determines the phase candidate θ by using the fifth projected image G5 to the sixth projected image G6, the first projected image G1, and the third projected image G3. Then, using these candidates, the measuring device 100 uses the phase Φ of the projected portion projected at the measurement position imaged by the cell 22p of the coordinates (x0, y0) in the pattern shown by the first projected image G1. To identify.
The measuring device 100 specifies the phase Φ by reducing the number of times the second wavelength image Ga20 is projected less than the number of times the first wavelength image Ga10 is projected.

A3: An example of the information processing device 3 FIG. 8 is a diagram showing an example of the information processing device 3. The information processing device 3 includes an operation unit 31, a display unit 32, a storage unit 33, and a processing unit 34.

The operation unit 31 is, for example, a keyboard, a mouse, an operation button, an operation key, or a touch panel. The operation unit 31 receives the input operation of the user.

The display unit 32 is an FPD (Flat Panel Display) such as a display, for example, a liquid crystal display, a plasma display, or an organic EL (Electro Luminescence) display. The display unit 32 displays various information.

The storage unit 33 is a recording medium that can be read by the processing unit 34. The storage unit 33 is composed of, for example, a non-volatile memory and a volatile memory. Examples of the non-volatile memory include ROM (Read Only Memory), EPROM (Erasable Programmable Read Only Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). Examples of the volatile memory include RAM (Random Access Memory).

The storage unit 33 stores the control program 331 executed by the processing unit 34 and various data 332s used by the processing unit 34. The data 332 includes, for example, the image data of each of the first projected image G1 to the sixth projected image G6.

The processing unit 34 is composed of, for example, a single processor or a plurality of processors. As an example, the processing unit 34 is composed of a single CPU (Central Processing Unit) or a plurality of CPUs (Central Processing Units). A part or all of the functions of the processing unit 34 may be configured by circuits such as DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate Array), and the like. .. The processing unit 34 executes various processes in parallel or sequentially.

By reading and executing the control program 331 from the storage unit 33, the processing unit 34 includes the projection control unit 341, the camera control unit 342, the first determination unit 343, the second determination unit 344, and the phase identification unit 345. , A distance specifying unit 346 and a display control unit 347 are included.

By controlling the projection unit 1, the projection control unit 341 projects each of the first projection image G1 to the sixth projection image G6 individually onto the object to be measured 200. For example, the projection control unit 341 reads each image data of the first projection image G1 to the sixth projection image G6 from the storage unit 33. The projection control unit 341 may generate image data of each of the first projection image G1 to the sixth projection image G6 according to the control program 331. The projection control unit 341 individually supplies the image data of the first projection image G1 to the sixth projection image G6 to the liquid crystal light valve 12, thereby supplying each of the first projection image G1 to the sixth projection image G6. It is individually projected onto the object to be measured 200.

The camera control unit 342 causes the camera 2 to generate the first captured image data to the sixth captured image data by controlling the camera 2. For example, the camera control unit 342 causes the image sensor 22 to image the object to be measured 200 each time the projection unit 1 individually projects the first projection image G1 to the sixth projection image G6 onto the object to be measured 200. The camera 2 is made to generate the first captured image data to the sixth captured image data.

The first determination unit 343 determines the phase candidate φ of the projection portion to the measurement position of the object to be measured 200 in the pattern shown by the first projection image G1 based on the first captured image data to the fourth captured image data. .. Hereinafter, the candidate φ determined by the first determination unit 343 is referred to as “first candidate φ”. The first determination unit 343 determines the first candidate φ for one measurement position by the number of cycles of the pattern indicated by the first projected image G1. The first candidate φ is also generally referred to as “relative phase”.

The first determination unit 343 determines the first candidate φ for each cell 22p of the image sensor 22, that is, for each measurement position of the object to be measured 200, using the above equations 5 to 9.

The second determination unit 344 is measured in the pattern shown by the fifth projected image G5 based on the first captured image data, the third captured image data, the fifth captured image data, and the sixth captured image data. The phase candidate θ of the projection portion of the object 200 to the measurement position is determined for each measurement position. Hereinafter, the candidate determined by the second determination unit 344 is referred to as a “second candidate θ”. The second determination unit 344 determines the second candidate θ for one measurement position by the number of cycles of the pattern indicated by the fifth projected image G5.

Brightness p ₅ in the toward direction X1 of the pattern indicated by the fifth projected image G5 is represented by Equation 10, the luminance p ₆ in toward the X1 direction of the pattern sixth projection image G6 is indicated and represented by Formula 11.
p ₅ = A · cos (hx) ・ ・ ・ Equation 10
p ₆ = A · cos (hx− (π / 2)) ・ ・ ・ Equation 11
In formulas 10 to 11, A is the same as A shown in formulas 1 to 4, and is also the amplitude of the brightness of each pattern of the fifth projected image G5 to the sixth projected image G6. That is, the amplitudes of the luminance of each pattern of the first projected image G1 to the sixth projected image G6 are the same as each other. h is a constant that determines the second predetermined wavelength λ2. x is the same as x shown in Equations 1 to 4, and indicates the coordinates of the fifth projected image G5 to the sixth projected image G6 in the X1 direction.

Further, in a situation where the fifth projected image G5 to the sixth projected image G6 are individually projected onto the object to be measured 200, the brightness value I observed by the cell 22p at the coordinates (x0, y0) in the image sensor 22 is determined.
I ₅ = {A · cos (θ) + G} × R ・ ・ ・ Equation 12
I ₆ = {A · cos (θ− (π / 2)) + G} × R ・ ・ ・ Equation 13
Will be.
The luminance value I ₅ is a luminance value observed by the cell 22p of the coordinates (x0, y0) in the situation where the fifth projected image G5 is projected.
The brightness value I ₆ is a brightness value observed by the cell 22p of the coordinates (x0, y0) in the situation where the sixth projected image G6 is projected.

The phase candidate θ is calculated by Equation 14 derived from Equations 12 to 13.
θ = tan ^-1 {(I _6- GR) / (I _5- GR)} ... Equation 14
In Equation 14, the unknown parameter is GR. GR is the product of "light components such as ambient light" and "reflectance of the measurement position of the object to be measured 200", and can be used in either the pattern shown by the second wavelength image Ga20 or the pattern shown by the first wavelength image Ga10. Is irrelevant. Therefore, when G and R do not change between the situation where the second wavelength image Ga20 is projected and the situation where the first wavelength image Ga10 is projected, the GR represented by the formulas 5 to 8 is expressed by the formula. It is the same value as GR shown in 12 to 14.

Therefore, the second determination unit 344 first calculates GR from the equations 5 and 7. Specifically, the second determination unit 344 calculates GR using the formula 15 derived based on the formula 5 and the formula 7.
GR = (I ₁ + I ₃ ) / 2 ・ ・ ・ Equation 15

Subsequently, the second determination unit 344 identifies the second candidate θ, that is, the phase candidate θ, by substituting the GR calculated from the equation 15 into the equation 14. Since the second wavelength image Ga20 shows a pattern for one cycle of the second sine wave, the number of the second candidate θ is one.

The phase specifying unit 345 uses the second candidate θ for the phase Φ of the projected portion projected at the measurement position imaged by the cell 22p of the coordinates (x0, y0) in the pattern shown by the first projected image G1. Then, it is specified from a plurality of first candidate φ.

For example, the phase specifying unit 345 first identifies the corresponding locations X11 to X14 using a plurality of first candidate φs, as illustrated in FIG. Specifically, the phase specifying unit 345 specifies the coordinate position in the X1 direction in the X1-Y1 coordinate system of the corresponding locations X11 to X14.
For example, the phase specifying unit 345 uses the first correspondence information indicating the correspondence between the phase of the pattern shown by the first projection image G1 and the position of the liquid crystal light bulb 12 in the X1 direction in the X1-Y1 coordinate system. Identify the relevant locations X11 to X14. The first correspondence information is stored in, for example, the storage unit 33.
The phase specifying unit 345 uses a function indicating the correspondence between the phase of the pattern shown by the first projected image G1 and the position of the liquid crystal light bulb 12 in the X1 direction in the X1-Y1 coordinate system, and uses a function indicating the correspondence between the corresponding portion X11. ~ X14 may be specified.
Further, the phase specifying unit 345 corresponds to the phase of the pattern shown by the first projected image G1 and the position in the X1-Y1 coordinate system in the direction along the epipolar line in the liquid crystal light valve 12 instead of the first correspondence information. The position in the X1-Y1 coordinate system in the direction along the epipolar line corresponding to the first candidate φ may be specified as the corresponding portion X11 to X14 by using the first epipolar correspondence information indicating the relationship. The epipolar line means the result of projection of a straight line connecting the object to be measured 200 and the camera 2 onto the virtual camera when the projection unit 1 is used as a virtual camera.

Subsequently, the phase specifying unit 345 identifies the corresponding portion X21 using one second candidate θ, as illustrated in FIG. 7. Specifically, the phase specifying unit 345 specifies the coordinate position in the X1 direction of the corresponding portion X21 in the X1-Y1 coordinate system.
For example, the phase specifying unit 345 uses the second correspondence information indicating the correspondence between the phase of the pattern shown by the fifth projection image G5 and the position of the liquid crystal light bulb 12 in the X1 direction in the X1-Y1 coordinate system. Identify the relevant location X21. The second correspondence information is stored in, for example, the storage unit 33.
The phase specifying unit 345 uses a function indicating the correspondence between the phase of the pattern shown by the fifth projected image G5 and the position of the liquid crystal light bulb 12 in the X1 direction in the X1-Y1 coordinate system, and uses the corresponding portion X21. May be specified.
Further, the phase specifying unit 345 corresponds to the phase of the pattern shown by the fifth projected image G5 and the position in the X1-Y1 coordinate system in the direction along the epipolar line in the liquid crystal light bulb 12 instead of the second correspondence information. The position in the X1-Y1 coordinate system in the direction along the epipolar line corresponding to the second candidate θ may be specified as the corresponding portion X21 by using the second epipolar correspondence information indicating the relationship.

Subsequently, the phase specifying unit 345 identifies, among the corresponding parts X11 to X14, the corresponding part closest to the corresponding part X21 in terms of distance as the corresponding part corresponding to the phase Φ. For example, when the corresponding parts X11 to X14 and the corresponding parts X21 are specified as shown in FIGS. 6 and 7, the corresponding parts X12 are specified as the corresponding parts corresponding to the phase Φ. Here, the specification of the corresponding portion corresponding to the phase Φ means that, for example, in FIG. 6, the first candidate φ included in the second cycle from the beginning is specified as the phase Φ.
The phase specifying unit 345 specifies the corresponding portion corresponding to the phase Φ for each measurement position.

The distance specifying unit 346 calculates the distance to the measurement position for each measurement position based on the corresponding portion corresponding to the phase Φ. For example, the distance specifying unit 346 calculates the distance to the measurement position using the triangulation based on FIG.

In FIG. 9, the projection direction D1 is parallel to the imaging direction D2. The liquid crystal light bulb 12 is set with an origin o1 which is an intersection of the liquid crystal light bulb 12 and the projection direction D1 and an axis X10 which passes through the origin o1 and is parallel to the X1 direction. The image sensor 22 is set with an origin o2 which is an intersection of the image sensor 22 and the image pickup direction D2, and an axis X20 which passes through the origin o2 and is parallel to the X1 direction. The distance Z represents the distance to the measurement position. The distance f represents the distance from the liquid crystal light bulb 12 to the projection optical system 13, and further represents the distance from the image sensor 22 to the light receiving optical system 21. The distance f is predetermined. The distance b is the distance between the projection optical system 13 and the light receiving optical system 21. The distance f is predetermined. The position xb in the image sensor 22 is a coordinate position determined based on the axis X20 of the cell 22p that is imaging the measurement position. The position xb has a positive value. The position xa in the liquid crystal light bulb 12 is a coordinate position determined based on the axis X10 of the corresponding portion specified by the phase specifying unit 345. The position xa has a negative value.

The distance specifying unit 346 calculates the position xa by converting the coordinate position in the X1 direction of the corresponding portion in the X1-Y1 coordinate system into a coordinate position determined based on the axis X10.
The distance specifying unit 346 calculates the position xa using, for example, coordinate conversion data that converts the coordinate position in the X1 direction of the X1-Y1 coordinate system into a coordinate position determined based on the axis X10.
Further, the distance specifying unit 346 calculates the position xb by converting the coordinate position in the X1 direction of the cell 22p that is imaging the measurement position in the X1-Y1 coordinate system to the coordinate position determined based on the axis X20. To do.
The distance specifying unit 346 calculates the position xb by using, for example, the coordinate conversion data that converts the coordinate position in the X1 direction of the X1-Y1 coordinate system into the coordinate position determined based on the axis X20.

Subsequently, the distance specifying unit 346 calculates the distance Z to the measurement position based on the equation 16.
Z = (f · b) / (xb-xa) ・ ・ ・ Equation 16
Equation 16 is derived from the fact that the triangle P1P2P3 has a similar relationship with the triangle P3P6P4 in FIG. The triangle P3P6P5 included in the triangle P3P6P4 is congruent with the triangle P2P7P8.
The distance specifying unit 346 calculates the distance Z to the measurement position imaged by the cell 22p for each measurement position, that is, for each of the cells 22p of the image sensor 22. The calculation result of the distance specifying unit 346 indicates the three-dimensional shape of the object to be measured 200.

The display control unit 347 controls the display unit 32. For example, the display control unit 347 causes the display unit 32 to display the calculation result of the distance specifying unit 346.

A4: Explanation of operation FIG. 10 is a flowchart for explaining the operation of the measuring device 100.
When the user operates the operation unit 31 to input a start instruction for the measurement operation, the projection control unit 341 supplies the image data of the first projection image G1 to the projection unit 1. Subsequently, in step S101, the projection unit 1 projects the first projection image G1 indicated by the image data supplied from the projection control unit 341 onto the object to be measured 200.

Subsequently, the camera control unit 342 supplies an image pickup instruction to the image pickup element 22. Subsequently, in step S102, the image sensor 22 generates the first captured image data by imaging the object 200 to be measured in response to the imaging instruction.

Subsequently, the projection control unit 341 supplies the image data of the second projection image G2 to the projection unit 1. Subsequently, in step S103, the projection unit 1 projects the second projection image G2 indicated by the image data supplied from the projection control unit 341 onto the object to be measured 200.

Subsequently, the camera control unit 342 supplies an image pickup instruction to the image pickup element 22. Subsequently, in step S104, the image sensor 22 generates the second image image data by imaging the object 200 to be measured in response to the image pickup instruction.

Subsequently, the projection control unit 341 supplies the image data of the third projection image G3 to the projection unit 1. Subsequently, in step S105, the projection unit 1 projects the third projection image G3 indicated by the image data supplied from the projection control unit 341 onto the object to be measured 200.

Subsequently, the camera control unit 342 supplies an image pickup instruction to the image pickup element 22. Subsequently, in step S106, the image sensor 22 generates the third captured image data by imaging the object 200 to be measured in response to the imaging instruction.

Subsequently, the projection control unit 341 supplies the image data of the fourth projection image G4 to the projection unit 1. Subsequently, in step S107, the projection unit 1 projects the fourth projection image G4 indicated by the image data supplied from the projection control unit 341 onto the object to be measured 200.

Subsequently, the camera control unit 342 supplies an image pickup instruction to the image pickup element 22. Subsequently, in step S108, the image sensor 22 generates the fourth image image data by imaging the object 200 to be measured in response to the image pickup instruction.

Subsequently, the projection control unit 341 supplies the image data of the fifth projection image G5 to the projection unit 1. Subsequently, in step S109, the projection unit 1 projects the fifth projection image G5 indicated by the image data supplied from the projection control unit 341 onto the object to be measured 200.

Subsequently, the camera control unit 342 supplies an image pickup instruction to the image pickup element 22. Subsequently, in step S110, the image sensor 22 generates the fifth captured image data by imaging the object to be measured 200 in response to the imaging instruction.

Subsequently, the projection control unit 341 supplies the image data of the sixth projection image G6 to the projection unit 1. Subsequently, in step S111, the projection unit 1 projects the sixth projection image G6 indicated by the image data supplied from the projection control unit 341 onto the object to be measured 200.

Subsequently, the camera control unit 342 supplies an image pickup instruction to the image pickup element 22. Subsequently, in step S112, the image sensor 22 generates the sixth captured image data by imaging the object 200 to be measured in response to the imaging instruction.

Subsequently, in step S113, the first determination unit 343 uses the above equations 5 to 9 based on the first captured image data to the fourth captured image data, and a plurality of first determination units 343 for each cell 22p of the image sensor 22. 1 Determine the candidate φ.

Subsequently, in step S114, the second determination unit 344 is based on the first captured image data, the third captured image data, the fifth captured image data, and the sixth captured image data, and the above equations 12 to 12 to The second candidate θ is determined for each cell 22p of the image pickup device 22 using the formula 15.

Subsequently, in step S115, the phase specifying unit 345 identifies the phase Φ from the plurality of first candidate φ by using the second candidate θ for each cell 22p of the image sensor 22. For example, the phase specifying unit 345 first identifies the corresponding locations X11 to X14 from the plurality of first candidate φs by using the above-mentioned first epipolar correspondence information. Subsequently, the phase specifying unit 345 identifies the corresponding portion X21 from one second candidate θ by using the above-mentioned second epipolar correspondence information. Subsequently, the phase specifying unit 345 identifies, among the corresponding parts X11 to X14, the corresponding part closest to the corresponding part X21 in terms of distance as the corresponding part corresponding to the phase Φ. The phase specifying unit 345 specifies the corresponding portion corresponding to the phase Φ for each measurement position.

Subsequently, in step S116, the distance specifying unit 346 calculates the distance to the measurement position for each measurement position using the above equation 16 based on the corresponding portion of the measurement position.

Subsequently, in step S117, the display control unit 347 causes the display unit 32 to display the calculation result of the distance by the distance specifying unit 346.

A5: Summary of the first embodiment According to the first embodiment, the three-dimensional shape of the object to be measured 200 can be measured by projecting the projected image six times, so that the phase Φ can be specified and the three-dimensional measurement can be performed in a short time. Can be done. Therefore, even when the illuminance of the external light illuminating the object to be measured 200 changes slowly and the object to be measured 200 moves slowly, the phase Φ can be specified with high accuracy and three-dimensional measurement can be performed. In addition, since the measurement time is short, it is possible to suppress giving the user mental stress related to the measurement.
The first embodiment can be applied to all three-dimensional shape measuring instruments used in robotics and the like. The first embodiment can also be applied to a projector that measures the three-dimensional shape of the projection surface and geometrically corrects the projected image according to the measurement result of the three-dimensional shape. In this case, the projection unit 1 includes the camera 2 and the information processing device 3.

The phase determination method and the measuring device 100 according to the present embodiment described above include the following aspects.
The projection unit 1 individually projects the first projection image G1 to the fourth projection image G4 onto the object to be measured 200. The first projected image G1 to the fourth projected image G4 show a pattern of brightness that changes according to a sine wave of the first predetermined wavelength λ1 in the X1 direction for two cycles or more. In the first projected image G1 to the fourth projected image G4, the phases of the sine waves having the first predetermined wavelength λ1 are different from each other.
Further, the projection unit 1 individually projects the fifth projection image G5 to the sixth projection image G6 onto the object to be measured 200. The fifth projected image G5 to the sixth projected image G6 show a pattern of brightness that changes according to a sine wave having a second predetermined wavelength λ2 longer than the first predetermined wavelength λ1 in the X1 direction. In the fifth projection image G5 to the sixth projection image G6, the phases of the sine waves having the second predetermined wavelength λ2 are different from each other.
The camera 2 images the object to be measured 200.
The first determination unit 343 is a first image pickup generated by the camera 2 taking an image of the object to be measured 200 in the first situation in which the first projected image G1 to the fourth projected image G4 are individually projected onto the object to be measured 200. A plurality of first candidates φ are determined based on the image data to the fourth captured image data.
The second determination unit 344 is a fifth image pickup generated by the camera 2 taking an image of the object to be measured 200 in the second situation in which the fifth projection image G5 to the sixth projection image G6 are individually projected onto the object to be measured 200. One second candidate θ is determined based on the image data to the sixth captured image data, the first projected image G1, and the third projected image G3.
The phase specifying unit 345 uses the second candidate θ to specify the phase Φ from the plurality of first candidate φ.

According to this aspect, the number of projections of the image showing the pattern corresponding to the sine wave of the first predetermined wavelength λ1 is longer than the first predetermined wavelength λ1 of the image showing the pattern corresponding to the sine wave of the second predetermined wavelength λ2. Since it is less than the number of projections, the time required to project an image showing a pattern can be shortened as compared with the case where both projections are equal to each other.
Further, the number of times the image of the pattern corresponding to the sine wave of the second predetermined wavelength λ2 is projected can be less than three times.

The second wavelength image Ga20 shows a pattern of brightness that changes in the X1 direction and that changes according to a sine wave of the second predetermined wavelength λ2 for only one cycle. Therefore, the number of the second candidate θ can be one. Therefore, the phase Φ can be specified from a plurality of first candidate φ by using one second candidate θ.

In the first embodiment, since the projection unit 1 and the camera 2 are arranged in the X1 direction, the X1 direction is used as the first direction and the second direction in which the brightness changes in each pattern. .. However, for example, when the projection unit 1 and the camera 2 are arranged in the Y1 direction, the Y1 direction may be used as the first direction and the second direction. Further, the first direction is preferably a direction along the second direction, but the first direction does not have to be a direction along the second direction. For example, the angle between the first direction and the second direction may be within 5 degrees.

B: Modification example The modification of the embodiment illustrated above will be illustrated below. Two or more embodiments arbitrarily selected from the following examples may be appropriately merged to the extent that they do not contradict each other.

B1: First Modified Example In the first embodiment, the second wavelength image Ga20 is a pattern of brightness that changes in the X1 direction, and is a third predetermined wavelength that is longer than the first predetermined wavelength λ1 and shorter than the second predetermined wavelength λ2. The pattern that changes according to the sine wave of λ3 may be shown more than one cycle. The third predetermined wavelength λ3 is another example of the second wavelength. In this case, the number of second candidate θ may be two or more. When the number of the second candidate θ is two or more, it is not possible to specify the phase Φ from the plurality of first candidate φ by using one second candidate θ as in the first embodiment.
Therefore, in the first modification, a measurement range capable of measuring the distance of the object to be measured 200 is preset, and a phase error range E corresponding to a distance exceeding this measurement range is preset. The second determination unit 344 determines the second candidate θ belonging to the error range E among the plurality of second candidate θ as an error value and deletes the second candidate θ, thereby reducing the number of the second candidate θ to one.

For example, as illustrated in FIG. 11, when the second wavelength image Ga20 shows a pattern that changes according to a sine wave of the third predetermined wavelength λ3 for two cycles, the two second candidates shown by black circles in FIG. 11 are shown. θ exists. The second determination unit 344 reduces the number of the second candidate θ to one by determining the second candidate θ belonging to the error range E as an error value and deleting the second candidate θ among the two second candidate θ. Hereinafter, the same operation as in the first embodiment is executed.

According to the first modification, the second wavelength image Ga20 shows more patterns of luminance that change according to the sine wave of the third predetermined wavelength λ3 in the X1 direction than for one cycle, so that the accuracy of the second candidate θ Can be higher than in the first embodiment.

B2: Second Modified Example In the first embodiment and the first modified example, the X1 direction is used as the first direction and the second direction. However, as the first direction and the second direction, the direction along the epipolar line may be used. FIG. 12 is a diagram showing an example of the first wavelength image Ga10 in which the direction along the epipolar line EPL is used as the first direction. The first determination unit 343 and the second determination unit 344 search for phase candidates in the direction along the epipolar line EPL.

According to the second modification, when the first wavelength image Ga10 shows a pattern of brightness that changes in the direction along the epipolar line EPL, the direction in which the brightness changes in the pattern is different from the direction along the epipolar line EPL. In comparison, the first candidate φ can be determined accurately.
Further, when the second wavelength image Ga20 shows a pattern of brightness that changes in the direction along the epipolar line EPL, the second candidate is compared with a configuration in which the direction in which the brightness changes in the pattern is different from the direction along the epipolar line EPL. θ can be determined accurately.

B3: Third Modified Example In the first embodiment and the first and second modified examples, the plurality of second wavelength images Ga20 are not patterns of brightness that are out of phase with each other by π / 2, but brightness that is out of phase with each other by π / 2. The pattern of may be shown.
In this case, in a situation where the fifth projected image G5 to the sixth projected image G6 are individually projected onto the object to be measured 200, the brightness value I observed by the cell 22p at the coordinates (x0, y0) in the image sensor 22 is determined.
I ₅ = {A · cos (θ) + G} × R ・ ・ ・ Equation 12
I ₇ = {A · cos (θ−π) + G} × R ・ ・ ・ Equation 17
Will be.
The luminance value I ₅ is a luminance value observed by the cell 22p of the coordinates (x0, y0) in the situation where the fifth projected image G5 is projected.
The luminance value I ₇ is a luminance value observed by the cell 22p of the coordinates (x0, y0) in the situation where the sixth projected image G6 is projected.

The second candidate θ is calculated using Equation 18 derived from Equation 12 and Equation 17.
cosθ = (I _5- I ₇ ) · (I _5- I ₇ ) / cosφ ... Equation 18

In Equation 18, the unknown parameter is cosφ.
cosφ is calculated by Equation 19 derived based on Equation 9 described above.
Since cosφ shown in equation 19 has an ambiguity of ± instead of one value, equation 18 to which cosφ is substituted also has ambiguity.
Therefore, the second wavelength image Ga20 has the first predetermined wavelength λ1 in the X1 direction so that the cosθ shown in the equation 18 always takes a value of 0 or more, in other words, the negative value of the cosφ value is removed. A pattern in which the brightness changes according to a sine wave having a longer fourth predetermined wavelength λ4 is shown for 1/2 cycle from 0 to π. The sine wave having the fourth predetermined wavelength λ4 is represented by the cosine wave whose phase is delayed by π / 2 from the cosine wave having the fourth predetermined wavelength λ4. Therefore, the phase candidate θ in Equation 18 is limited to the range of −π / 2 to π / 2. The second determination unit 344 calculates cos θ by substituting a value of 0 or more into the equation 18 among the values calculated by the equation 19, and determines the second candidate θ from the calculation result. Hereinafter, the same operation as in the first embodiment is executed.

When the phase error range E is preset as in the first modification, the second wavelength image Ga20 has a luminance pattern that changes in accordance with the sine wave of the fourth predetermined wavelength λ4 in the X1 direction. It may be shown more than / 2 cycles. In this case, as in the first modification, the second determination unit 344 determines the second candidate θ belonging to the error range E among the plurality of second candidate θ as an error value and deletes the second candidate θ. Set the number of candidate θ to one.

According to the third modification, even if the plurality of second wavelength images Ga20 show luminance patterns that are out of phase with each other, it is possible to obtain the second candidate θ.

B4: Fourth Modified Example In the first embodiment and the first to third modified examples, the projection unit 1 has a seventh projection image G7 to a twelfth projection image in addition to the first projection image G1 to the sixth projection image G6. G12 may be projected.

FIG. 13 is a drawing showing an example of the first projected image G1 to the twelfth projected image G12. As illustrated in FIG. 13, the seventh projection image G7 to the tenth projection image G10 are the first projection images G1 to the fourth projection in that the direction in which the brightness changes in the pattern is not the X1 direction but the Y1 direction. Different from image G4. The pattern shown by the seventh projected image G7 is an example of the third pattern. The first predetermined wavelength λ1 is also an example of the third wavelength.

Further, the eleventh projected images G11 to the twelfth projected images G12 are different from the fifth projected images G5 to the sixth projected images G6 in that the direction in which the brightness changes in the pattern is not the X1 direction but the Y1 direction. The pattern shown by the eleventh projected image G11 is an example of the fourth pattern. The second predetermined wavelength λ2 is also an example of the fourth wavelength.

The Y1 direction is an example of the third direction and the fourth direction. The third direction is preferably a direction along the fourth direction, but the third direction does not have to be a direction along the fourth direction. For example, the angle between the third direction and the fourth direction may be within 5 degrees.
In the fourth modification, the projection unit 1 and the camera 2 do not have to be aligned in the direction along the X1 direction.

The camera 2 further images the object to be measured 200 by the image sensor 22 in a situation where each of the seventh projected image G7 to the tenth projected image G10 is individually projected onto the object to be measured 200.

The image sensor 22 generates the seventh captured image data by imaging the measured object 200 in a situation where the seventh projected image G7 is projected onto the measured object 200. The image sensor 22 generates the eighth captured image data by imaging the measured object 200 in a situation where the eighth projected image G8 is projected onto the measured object 200. The image sensor 22 generates the ninth captured image data by imaging the measured object 200 in a situation where the ninth projected image G9 is projected onto the measured object 200. The image sensor 22 generates the tenth captured image data by imaging the measured object 200 in a situation where the tenth projected image G10 is projected onto the measured object 200. Each of the 7th captured image data to the 10th captured image data is an example of the 3rd captured image data.

Further, the camera 2 further images the object to be measured 200 by the image sensor 22 in a situation where each of the eleventh projected images G11 to the twelfth projected images G12 is individually projected onto the object to be measured 200.

The image sensor 22 generates the eleventh captured image data by imaging the measured object 200 in a situation where the eleventh projected image G11 is projected onto the measured object 200. The image sensor 22 generates the twelfth captured image data by imaging the measured object 200 in a situation where the twelfth projected image G12 is projected onto the measured object 200. Each of the 11th captured image data to the 12th captured image data is an example of the 4th captured image data.

The first determination unit 343 further determines the phase candidate φa of the projection portion to the measurement position of the object to be measured 200 in the pattern shown by the seventh projection image G7 based on the seventh captured image data to the tenth captured image data. To do. The method for determining the phase candidate φa is the same as the method for determining the first candidate φ.

The second determination unit 344 is measured in the pattern shown by the seventh projected image G7 based on the seventh captured image data, the ninth captured image data, the eleventh captured image data, and the twelfth captured image data. The phase candidate θa of the projection portion of the object 200 to the measurement position is further determined for each measurement position. The method for determining the phase candidate θa is the same as the method for determining the second candidate θ.

The phase specifying unit 345 uses the phase candidate θa for the phase Φa of the projected portion projected at the measurement position imaged by the cell 22p of the coordinates (x0, y0) in the pattern shown by the seventh projected image G7. Then, it is specified from a plurality of phase candidates φa. The method for specifying the phase Φa is the same as the method for specifying the phase Φ.

The distance specifying unit 346 uses the phase Φa to specify the distance to the measurement position imaged by the cell 22p at the coordinates (x0, y0). The distance specifying unit 346 further calculates the average of the distance specified by using the phase Φ and the distance specified by using the phase Φa. The display control unit 347 displays the average distance calculated by the distance specifying unit 346 on the display unit 32.

The display control unit 347 displays only the distance specified by the operation of the operation unit 31 among the distance specified by using the phase Φ and the distance specified by using the phase Φa on the display unit 32. You may. For example, when the projection unit 1 and the camera 2 are arranged side by side in the X1 direction, the user specifies a distance specified by using the phase Φ by operating the operation unit 31. On the other hand, when the projection unit 1 and the camera 2 are arranged side by side in the Y1 direction, the user specifies a distance specified by using the phase Φa by operating the operation unit 31.

According to the fourth modification, the distance can be accurately specified regardless of the relative positional relationship between the projection unit 1 and the camera 2.

B5: Fifth Modified Example In the first embodiment and the first to fourth modified examples, the liquid crystal light valve 12 was used as an example of the light modulation device, but the light modulation device is not limited to the liquid crystal light valve and can be appropriately changed. is there. For example, the optical modulation device may have a configuration such as a method using one digital mirror device. In addition to the liquid crystal panel and DMD, a configuration capable of modulating the light emitted by the light source 11 can be adopted as the optical modulation device.

1 ... Projection unit, 2 ... Camera, 3 ... Information processing device, 11 ... Light source, 12 ... Liquid crystal light valve, 13 ... Projection optical system, 21 ... Light receiving optical system, 22 ... Image sensor, 31 ... Operation unit, 32 ... Display Unit, 33 ... Storage unit, 34 ... Processing unit, 100 ... Measuring device, 200 ... Measured object, 341 ... Projection control unit, 342 ... Camera control unit, 343 ... First determination unit, 344 ... Second determination unit, 345 ... Phase specifying unit, 346 ... Distance specifying unit, 347 ... Display control unit.

Claims (6)

It is a phase determination method executed by the measuring device.
A plurality of first images in which the brightness changes according to the sine wave of the first wavelength for two cycles or more in the first direction and the phases of the sine waves of the first wavelength are different from each other are individually measured. Project to
A plurality of second images in which the brightness changes according to the sine wave of the second wavelength longer than the first wavelength in the second direction and the phases of the sine waves of the second wavelength are different from each other are individually displayed. Project on the object to be measured
The first imaging data is generated by imaging the object to be measured in the first situation in which the plurality of first images are individually projected onto the object to be measured.
The second imaging data is generated by imaging the object to be measured in the second situation in which the plurality of second images are individually projected onto the object to be measured.
The phase candidate of the projection portion to the measurement position of the object to be measured in the first pattern, which is the pattern shown in any of the plurality of first images, is determined based on the first imaging data.
The phase candidate of the projection portion to the measurement position in the second pattern, which is the pattern shown in any of the plurality of second images, is determined based on the first imaging data and the second imaging data.
The phase of the first pattern in the projection portion to the measurement position is specified from the phase candidates of the first pattern by using the phase candidates of the second pattern.
The number of the plurality of second images is smaller than the number of the plurality of first images.
Phase determination method. The second image shows a pattern in which the brightness changes according to the sine wave of the second wavelength in the second direction for only one cycle.
The phase determination method according to claim 1. The second image shows more patterns in which the brightness changes in accordance with the sine wave of the second wavelength in the second direction than for one cycle.
The phase determination method according to claim 1. The projection unit projects the plurality of first images and the plurality of second images onto the object to be measured.
The camera captures the object to be measured in the first situation and the second situation.
When the projection unit is a virtual camera,
The first direction and the second direction are directions along an epipolar line which is a result of projection of a straight line connecting the object to be measured and the camera onto the virtual camera.
The phase determination method according to any one of claims 1 to 3. A pattern in which the brightness changes according to the sine wave of the third wavelength is shown for two cycles or more in the third direction, and a plurality of third images having different phases of the sine wave of the third wavelength are individually measured. Project to an object
A plurality of fourth images in which the brightness changes according to the sine wave of the fourth wavelength longer than the third wavelength in the fourth direction and the phases of the sine waves of the fourth wavelength are different from each other are individually displayed. Project to the object to be measured
Third imaging data is generated by imaging the object to be measured in a situation where the plurality of third images are individually projected onto the object to be measured.
The fourth imaging data is generated by imaging the object to be measured in a situation where the plurality of fourth images are individually projected onto the object to be measured.
The phase candidate of the projection portion to the measurement position in the third pattern, which is the pattern shown in any of the plurality of third images, is determined based on the third imaging data.
The phase candidate of the projection portion to the measurement position in the fourth pattern, which is the pattern shown in any of the plurality of fourth images, is determined based on the third imaging data and the fourth imaging data.
The phase of the third pattern in the projection portion to the measurement position is specified from the phase candidates of the third pattern by using the phase candidates of the fourth pattern.
The number of the plurality of fourth images is smaller than the number of the plurality of third images.
The first direction does not intersect the second direction and
The third direction does not intersect with the fourth direction,
The first direction intersects the third direction.
The phase determination method according to any one of claims 1 to 4. A plurality of first images in which the brightness changes according to the sine wave of the first wavelength for two cycles or more in the first direction and the phases of the sine waves of the first wavelength are different from each other are individually measured. A plurality of second images in which the brightness changes according to the sine wave of the second wavelength longer than the first wavelength in the second direction, and the phases of the sine waves of the second wavelength are different from each other. To the projection unit that individually projects the object to be measured, and
A camera that captures the object to be measured and
In the first situation where the plurality of first images are individually projected onto the object to be measured, the plurality of first images are based on the first imaging data generated by the camera imaging the object to be measured. A first determination unit that determines a candidate for the phase of the projection portion to the measurement position of the object to be measured in the first pattern, which is a pattern shown in any one of them,
Based on the second imaging data generated by the camera imaging the object to be measured in the second situation in which the plurality of second images are individually projected onto the object to be measured, and the first imaging data. The second determination unit, which determines the phase candidate of the projection portion to the measurement position in the second pattern, which is the pattern shown in any of the plurality of second images,
A phase specifying unit that specifies the phase of the first pattern in the projection portion to the measurement position from the phase candidates of the first pattern using the phase candidates of the second pattern.
Including
The number of the plurality of second images is smaller than the number of the plurality of first images.
Measuring device.