JP2001108420A - Device and method for shape measurement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for shape measurement which are small-sized and inexpensive, has high light use efficiency, and can accurately measure the distance to a body without being affected by external conditions such as a difference in the reflection factor of the body surface. SOLUTION: First and second shutters 11A and 11B are opened and a semiconductor laser 3 emits intensity-modulated illumination light 4a. A plane sensor 9 detects the composite light of reflected light 4b from an object 6 and reference light 4c from a half-mirror 10 and outputs a detection signal. The 2nd shutter 11B is closed and the semiconductor laser 3 emits intensity-modulated illumination light 4b. A distance arithmetic part 13 after making corrections for removing the influence of the reflection factor of the body according to the detection signal of the composite light and the detection signal of the reflected light 4b calculates the distance to the body according to the detection signal of the composite light which has been corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring apparatus which emits intensity-modulated outgoing light toward an object and measures a distance to the object based on a phase difference between reflected light from the object and emitted light. And shape measurement methods, especially those that are small and inexpensive, have high light use efficiency, and can accurately measure the distance to an object without being affected by external conditions such as differences in the reflectance of the object surface. The present invention relates to an apparatus and a shape measurement method.

[0002]

2. Description of the Related Art As a method for measuring a three-dimensional shape, two methods, a passive method and an active method, have been proposed. The passive method is a method of measuring a shape without radiating energy to a target object, and the active method is a method of measuring a shape by radiating some energy to a target object and detecting its reflection.

In the passive method, there is a stereo method as one of the methods for measuring the distance of a plurality of points to a target object. The stereo method is a method in which two cameras are installed at a certain interval, and the distance to a target object is measured by a trigonometric method from the parallax of two obtained images. This method has the advantage that it can measure the distance to a distant place if it can be captured as an image, but it has a serious problem that it is not possible to perform three-dimensional measurement of the entire surface with a smooth surface without patterns There is a point. In addition, since the optical axes of the two cameras cannot be matched in principle, there is a disadvantage that an area (occlusion) where the distance cannot be measured occurs.

In the active method, there is a light section method as one of the methods for measuring the distance of a plurality of points to a target object. This light cutting method is a method of irradiating a target object with slit light at a certain angle, and measuring the distance to the target object by triangulation from an image taken from another angle. This method has the advantage that it can be realized with a relatively simple configuration, but the slit light has to be scanned in small angle units, and an image is taken each time, so that the measurement time becomes longer. There is. In order to solve this problem, there is a spatial coding method as a method applying the light sectioning method. This spatial coding method measures the distance with a small number of projections by coding the pattern of the projection light instead of irradiating the slit light many times, but the number of samples in the horizontal direction is n. Then, since it is necessary to perform log ₂ n times (n = 512 points and nine times) of imaging, there is a problem that the measurement time becomes long. Also,
Area where the distance cannot be measured because the optical axis of the projector and the imager cannot be matched in principle (occlusion)
However, there is a drawback that the problem occurs.

In the active method, as one of the methods capable of measuring the distance between a plurality of points by one imaging, a phase distribution measuring method of irradiating an object with intensity-modulated light and measuring the phase distribution of the reflected light. There is.

[0006] As a conventional phase distribution measurement method, for example, a paper described in Reference 1 “SPIE Vol, 2588, 1995, pp. 126-134 (An new active 3D-Vision system base)
d on rf-modulation interferometry light), and Patent No. 2690673, and SPIE Vol. 2748, 1966.
Year, p. 47-59 `` The Emerging Versatility of a Sc
annless Range Imager ".

FIG. 8 shows a conventional shape measuring device disclosed in Document 1. The shape measuring device 100 includes a light source 101A
And a modulation / demodulation signal generator 104 for performing intensity modulation on light emitted to a plane modulator 103 using a crystal such as a Pockels cell via a condenser lens 102, and an intensity-modulated light 105a to the target object 6. Projection lens 1 for flat illumination
06 and a plane demodulator 108 using a crystal such as a Pockels cell reflected by the target object 6 via an imaging lens 107.
A modulation / demodulation signal generator 104 for demodulating the intensity of the reflected light 105b incident on the optical disc 105b, and a CCD camera 109 for imaging the optical signal subjected to the intensity demodulation. In such a configuration, the light emitted from the light source 101A is incident on the plane modulator 103 by the condenser lens 102 and is subjected to intensity modulation based on the signal of the modulation / demodulation signal generator 104. The intensity-modulated light 105a is transmitted to the projection lens 10
6 irradiates the target object 6 in a plane. The reflected light 105b from the target object 6 is incident on the plane demodulator 108 by the imaging lens 107, and is subjected to intensity demodulation based on the signal of the modulation / demodulation signal generator 104.
Image on top. The grayscale image captured by the CCD camera 109 includes phase information resulting from the distance to the target object 6. By processing the grayscale image by the computer 110, the distance data of the target object 6 can be obtained by one imaging.

FIG. 9 shows a conventional shape measuring device described in Japanese Patent No. 2690673. The difference from FIG. 8 is that the semiconductor laser 101B is used as a light source, the intensity modulation is performed directly by the semiconductor laser 101B without using a modulator using a crystal such as a Pockels cell, The third point is that demodulation is performed by the image intensifier 111 without using a demodulator using a crystal. Modulation / demodulation signal generator 104
Is emitted from the semiconductor laser 101B, and then is projected onto the target object 6 by the projection lens 106. The reflected light 105b from the target object 6 is imaged by the imaging lens 107 on the image intensifier 111. The signal from the modulation / demodulation signal generator 104 is converted into a high-voltage signal by the high-voltage drive circuit 112, and is input to the gain controller terminal of the image intensifier 111. . The grayscale image captured by the CCD camera 109 includes phase information resulting from the distance to the target object 6. Computer 11
By processing this grayscale image with 0, the distance data of the target object 6 can be obtained by one imaging.

However, according to the shape measuring apparatus 100 shown in FIG. 8, since a modulator / demodulator using a crystal such as a Pockels cell is used for the plane modulator 103 and the plane demodulator 108, a very expensive apparatus is used. There was a disadvantage that it would be. Since the modulator / demodulator using this crystal has an aperture as small as about several millimeters, the condenser lens 107 adjusts the light emitted from the light source 101A and the light reflected by the target object 6 in accordance with the aperture. It has to be used to collect light, and there is a disadvantage that the device becomes large. Further, according to the shape measuring apparatus 100 shown in FIG. 9, since the image intensifier 111 is used, there is a disadvantage that the apparatus becomes very expensive. Further, in order to drive the image intensifier 111, it is necessary to modulate the intensity of a high voltage signal of several hundred volts, so that there is a disadvantage that the drive circuit becomes complicated.
The image intensifier 111 is a CCD
There is a drawback that the entire apparatus becomes large because it is larger than the camera 109.

Therefore, as a method of measuring distance without using an expensive modulator / demodulator or an expensive and large image intensifier, a conventional shape measuring device using a phase distribution measuring method using a reference light, for example, , Tokubo Sho5
There is one disclosed in Japanese Patent Publication No. 9-30233.

FIG. 10 shows the conventional shape measuring apparatus. The shape measuring device 100 includes a light emitting element 123 that emits light whose intensity is modulated at a predetermined frequency by a driving signal from a driving circuit 121 based on a signal of an oscillator 120,
A beam splitter 125 for transmitting and reflecting light incident from the light emitting element 123 via the projection lens 124,
The light transmitted through the beam splitter 125, reflected by the object 6, and reflected again by the beam splitter 125, and the light reflected by the beam splitter 125, reflected by the reflecting mirror 128, and transmitted through the beam splitter 125 again are collected by the condenser lens 1.
A light receiving element 127 for receiving light through the light receiving element 26;
, An amplifier 128 for amplifying the output signal of
And a level meter 130 for reading the amplitude from the output signal of the detector 129.

In such a configuration, when light whose intensity is modulated at a predetermined frequency by the driving signal from the driving circuit 121 based on the signal of the oscillator 120 is emitted from the light emitting element 123, the light is transmitted through the projection lens 124. Incident on the beam splitter 125. Beam splitter 12
One light (illumination light) transmitted by 5 is reflected by the object 6, is reflected again by the beam splitter 125, and is incident on the light receiving element 127 via the condenser lens 126. The other light (reference light) reflected by the beam splitter 125 is reflected by a reflecting mirror 128 provided at a known distance, transmitted by the beam splitter 125, and similarly incident on the light receiving element 127. These two lights are received by the light receiving element 1
Optically synthesized on 27, the waveform is converted into an electric signal and sent to an amplifier 128. The amplitude of this waveform changes depending on the difference between the distance from the light receiving element 127 to the object 6 and the distance from the light receiving element 127 to the reflecting mirror 128. The distance to the object 6 can be calculated by detecting the amplified waveform signal with the detector 129 and reading the amplitude with the level meter 130.

[0013]

However, according to the conventional shape measuring apparatus, both the illumination light and the reference light are transmitted from the light emitting element 123 to the light receiving element 127 by the beam splitter 125.
Twice, the amount of light incident on the light receiving element 127 becomes に of the outgoing light, and there is a problem that the light use efficiency is poor. Further, since the light incident on the light receiving element 127 includes the influence of the reflectance of the surface of the object 6, the light receiving element 127
Since the distance to the object 6 is calculated based on the output signal of the object 6, there is a problem that an accurate distance cannot be measured due to a difference in reflectance of the surface of the object 6. Furthermore, it is not possible to measure an accurate distance with an object having unevenness with respect to the optical axis. There is no problem in a dark place, but an accurate distance cannot be measured in a place with external light. There is a serious drawback that distance measurement cannot be performed in a normal use environment, such as the need to perform dimensional scanning and a long measurement time.

Accordingly, it is an object of the present invention to provide a small and inexpensive shape measuring device having high light use efficiency. Another object of the present invention is to provide a shape measuring device and a shape measuring method capable of accurately measuring a distance to an object without being influenced by external conditions such as a difference in reflectance of the surface of the object. It is in.

[0015]

According to the present invention, in order to achieve the above object, the present invention emits outgoing light whose intensity is modulated at a predetermined frequency toward an object, and outputs the reflected light from the object and the outgoing light. In a shape measuring device that measures a distance to the object based on a phase difference, a light emitting unit that emits the intensity-modulated outgoing light toward the object at the predetermined frequency, and a light emitted from the light emitting unit. A reflection member that reflects the emitted light in a predetermined direction, and a combined detection signal that receives the reflected light from the object and the emitted light from the reflective member and reflects the phase difference by combining them. Detecting means for receiving the reflected light reflected by the object by emitting the emitted light and receiving a reflected light detection signal, and receiving the emitted light from the reflecting member and outputting a reference light detection signal; and Detection signal Calculating means for calculating the distance by performing a correction for removing an external component such as a difference in reflectance of the object surface based on the reflected light detection signal and the reference light detection signal. To provide a shape measuring device.

According to the above configuration, as the reflecting member, for example, a beam splitter for transmitting and reflecting the outgoing light at a predetermined ratio or a reflecting mirror provided at a position that does not hinder the irradiation of the outgoing light to the object is used. be able to.
By using a beam splitter as a reflection member,
Since the number of times that the output light passes through the beam splitter is one, it is possible to suppress the amount of the reflected light and the output light received by the detection unit from being reduced by the beam splitter. By using the above-mentioned reflecting mirror as a reflecting member, it is possible to prevent the amount of reflected light and outgoing light received by the detecting means from being reduced by the reflecting mirror. Further, based on the combined detection signal, the reflected light detection signal and the reference light detection signal,
By performing a correction for removing an external component such as a difference in the reflectance of the object surface, the distance to the object can be accurately obtained.

[0017]

FIG. 1 shows a three-dimensional shape measuring apparatus according to a first embodiment of the present invention. The device 1 includes a modulation signal generator 2 for generating a modulation signal, a semiconductor laser 3 for emitting illumination light 4a composed of laser light intensity-modulated based on the modulation signal from the modulation signal generator 2, and a semiconductor laser. A projection lens 5 for irradiating the illumination light 4a from 3 toward the target object 6, an imaging lens 7 for forming an image of the reflected light 4b reflected by the target object 6 on the flat sensor 9 via the optical filter 8, The illumination light 4a from the semiconductor laser 3 is transmitted and reflected, and the reflected laser light is used as the reference light 4c via the optical filter 8 and the flat sensor 9 as the reference light 4c.
A half mirror 10 leading upward, a first shutter 11A arranged between the target object 6 and the optical filter 8, and a second shutter 11A arranged between the half mirror 10 and the optical filter 8.
, A two-dimensional image memory 12 for storing the output signal of the plane sensor 9 as density information, and two-dimensional distance data relating to the surface shape of the target object 6 based on the density information stored in the image memory 12. And a CPU 14 for controlling each unit of the apparatus 1.

First and second shutters 11A and 11B
For example, a device in which a single crystal plate having an electro-optical effect and having transparent electrodes provided at both ends between a polarizer and an analyzer can be used. Note that a liquid crystal, a mechanical type, or the like may be used. In the present embodiment, voltage application (ON)
That transmits incident light.

FIG. 2 shows one pixel circuit constituting the flat sensor 9. The plane sensor 9 has an amplitude detection mode and a light amount detection mode, and includes a plurality of pixels arranged two-dimensionally. One pixel includes a photodiode 90, a first bypass circuit switching unit 91A, a high pass filter (HPF) 92, a comparator 93a,
It is connected to a peak hold circuit 93 including a diode 93b and a capacitor 93c, a current conversion circuit 94, a second bypass circuit switching unit 91B, a first bypass circuit switching unit 91A, and a second bypass circuit switching unit 91B. , HPF 92 and a bypass line 95 for bypassing the peak hold circuit 93, a switch 96, and a charge storage circuit 97.

FIGS. 3A to 3D show the operation of the flat sensor 9. FIG. First and second bypass circuit switching unit 9
When 1A and 91B are set to the A side, a signal Sa is output from the photodiode 90 as shown in FIG.
The output signal Sa of the photodiode 90 is the HPF 9
In step 2, the DC component V ₀ is cut off to become a high-frequency signal Sb shown in FIG. The peak hold circuit 93 outputs a peak value signal Sc holding the peak value of the amplitude as shown in FIG. Since this peak value signal Sc has a very low voltage and is difficult to detect, it is converted into a current by the current conversion circuit 94 and then stored in the charge storage circuit 97 for a certain period of time. The storage voltage Sd of the charge storage circuit 97 is as shown in FIG.
As shown in, increases linearly, when compared with the modulation frequency omega / 2 [pi of laser light period the integral of a sufficiently large time T _1, a readily detectable voltage value V. It is clear that this voltage value V is proportional to the amplitude of the combined light. The voltage value V in the data transfer period T ₂ are transferred to the distance calculation unit 13.
From the charge storage circuit 97, the amplitude of the intensity-modulated light from the target object 6 is detected, and an image signal including phase data corresponding to the distance to the target object 6 is obtained. In the discharging period T3, the charge storage circuit 97 is grounded by the switch 96, the stored charge is released, and then the storage is started again.
On the other hand, the first and second bypass circuit switching units 91
When A and 91B are set to the B side, the photodiode 90
Is directly input to the charge storage circuit 97, the average luminance of the stationary light from the target object 6 is detected, and the luminance data of the target object 6 is obtained. With these circuits, the amplitude of the high frequency component of the output signal Sa of the photodiode 90 can be detected in the form of a voltage.

Next, the operation of the apparatus 1 will be described with reference to FIGS. 4 and 5 and the flowchart of FIG. FIGS. 4A and 4B are diagrams showing, by computer simulation, that the amplitude of the combined light changes due to the phase delay of the reflected light 4b. FIG. 5A shows an imaging state using the illumination light 4a, the reference light 4c, and the external light 4d, and FIG.
Indicates an imaging state using the illumination light 4a and the external light 4d,
FIG. 5C shows an imaging state using only the reference light 4c.

(1) Imaging with illumination light 4a, reference light 4c and external light 4d Here, as shown in FIG. 5A, intensity-modulated illumination light 4a, reference light 4c and external light 4d are used. The target object 6 is imaged under the set lighting conditions (ST1). That is, CP
U14 generates the intensity-modulated illumination light 4a from the semiconductor laser 3 according to the control signal to the modulation signal generator 2. Further, the CPU 14 controls the first and second shutters 1.
1A and 11B, the shutters 11A,
11B is opened, and all the reflected light 4b from the target object 6 and the reference light 4c are transmitted. That is, the illumination light 4 a from the semiconductor laser 3 enters the half mirror 10 via the projection lens 5. The illumination light 4a that has entered the half mirror 10 is split into transmitted light and reflected light.
The illumination light 4a transmitted through the half mirror 10
The reflected light 4b reflected by the target object 6 passes through the imaging lens 7 and the first shutter 11A, and forms an image on the flat sensor 9 via the optical filter 8. The reference light 4c reflected by the half mirror 10 is transmitted to the second shutter 1
The light enters the flat sensor 9 via the optical filter 1B and the optical filter 8. Therefore, the combined light of the reflected light 4b and the reference light 4c enters the flat sensor 9. Further, the CPU 14 sets the light detection mode of the flat sensor 9 to the amplitude detection mode for detecting the amplitude of the intensity-modulated light according to the control signal to the flat sensor 9. By taking an image in this state, the amplitude information of the combined light of the reflected light 4b and the reference light 4c as expressed by Expression (6) described later is stored in the image memory 12 as grayscale information (image data An). .

(2) Imaging with illumination light 4a and external light 4d Here, as shown in FIG. 5 (b), illumination light 4a whose intensity is modulated is irradiated, reference light 4c is blocked, and external light 4d is The target object 6 is imaged in the irradiated state (ST2). That is, the CPU 14 generates the intensity-modulated illumination light 4 a from the semiconductor laser 3 by the control signal to the modulation signal generator 2. Further, the CPU 14 opens the first shutter 11A, closes the second shutter 11B in response to a control signal to the first and second shutters 11A and 11B, and controls the reflected light 4b from the target object 6. Is transmitted, the reference light 4c is shielded, and the light detection mode of the plane sensor 9 is set to an amplitude detection mode for detecting the amplitude of the intensity-modulated light by a control signal to the plane sensor 9. By taking an image in this state, the amplitude information of the reflected light 4b represented by the expression (7) described later is two-dimensionally recorded in the image memory 12 as light and shade information (image data Bn).

(3) Imaging Using Only Reference Light 4c Next, the CPU 14 operates the semiconductor laser monitor output line 14a.
Is monitored (ST3), and if the fluctuation of the laser output is larger than the set threshold, the following imaging is performed (ST4). If the fluctuation of the laser output is smaller than the set threshold value, the imaging ends. However, the density information (image data Cn) obtained by performing the following imaging only once at the time of activation of the present apparatus 1 is stored in the image memory 12 and used for calculating distance data described later. Here, as shown in FIG. 5C, the reflected light 4b from the target object 6 is shielded, and only the reference light 4c is imaged. That is, the CPU 14 controls the modulation signal generator 2
, The semiconductor laser 3 generates intensity-modulated illumination light 4a. Further, the CPU 14
The first shutter 11A is closed and the second shutter 11B is opened according to a control signal to the second shutters 11A and 11B, and the reflected light 4b from the target object 6 is set.
Is shielded, and the reference light 4c is transmitted. Further, the light detection mode of the plane sensor 9 is set to an amplitude detection mode for detecting the amplitude of the intensity-modulated light according to a control signal to the plane sensor 9. By taking an image in this state, the following equation (8) is obtained.
Is two-dimensionally recorded in the image memory 12 as density information (image data Cn).

(4) Two-dimensional calculation of distance data The distance calculation unit 13 calculates the following equation (12) based on the two or three pieces of image data An, Bn, and Cn thus captured.
To calculate distance data two-dimensionally (ST5).

Hereinafter, this calculation will be described in detail. Assuming that the angular frequency of the modulation is ω and the amplitude is 2E, the illumination light 4a composed of the intensity-modulated light emitted from the semiconductor laser 3 is expressed by the following equation (1). I ₀ = E (sin ωt + 1) (1)

If the distance to the target object 6 is 0 to 2.5 m, the required modulation frequency is 30 MHz. Assuming that the light transmittance of the half mirror 10 is a and the reflection coefficient at a certain point on the target object 6 is C _n , the intensity of the reflected light 4 b incident on the point n where the point is imaged on the flat sensor 9 is , The intensity of the external light 4d is represented by e, and is expressed by the following equation (2). I _n = d ₁ C _n · aE {sin (ωt + φ _n ) +1} + e (2)

Here, d ₁ is a constant determined by the optical system (projection system and imaging system) of the apparatus 1, and φ _n is a phase delay caused by a flight distance of light incident on the flat sensor 9 from the light source. is there. (Semiconductor laser 3 to target object 6) + (target object 6
Ｌ _n = ωL / C where C is the speed of light

On the other hand, assuming that the reflectance of the half mirror 10 is b and the optical path length from the semiconductor laser 3 to the plane sensor 9 and the size of the plane sensor 9 are sufficiently smaller than the wavelength of the modulated wave, The intensity of the reference light 4c on the sensor 9 becomes uniform, and at the point n on the flat sensor 9, it is expressed by the following equation (3). R _n = d ₂ bE (sinωt + 1) (3) where d ₂ is a constant determined by the optical system (imaging system) of the device 1.

The light intensity P _n at the point n on the flat sensor 9
Is a combined light of the reflected light 4b and the reference light 4c, and the expression (2)
Expression (4) is obtained by adding Expression (3) and Expression (3).

(Equation 1) However,

(Equation 2) In FIG. 4A, when the distance to the target object 6 is relatively small, that is, when the phase delay is small (π / 4 delay), the amplitude of the combined light increases. In FIG. 2B, when the distance to the target object 6 is relatively large, that is, when the phase delay is large (7π / 8 delay), the amplitude of the combined light is small. Combined light, as represented by the above formula (4), DC component _{(d 1 C n a + d} 2 b) E + e and the high frequency component

(Equation 3) Is the sum of D ₁ · C _n · aE and d ₂ · bE appearing in the amplitude term are the amplitude components of the reflected light (including the surface reflectance of the object 6) 4 b and the reference light 4 c when irradiating the light whose intensity is not modulated. Therefore, it is possible to measure in advance as follows.

[0031] When the imaging state of FIG. 5 (a), when the amplitude of the intensity-modulated light incident on the planar sensor 9 and 2A _n, A _n can be expressed as the following equation (6).

(Equation 4) In the imaging state of FIG. 5B, the intensity of light incident on the flat sensor 9 is expressed as follows. Set the amplitude of the intensity modulated light to 2
Assuming B _n , B _n is represented by the following equation (7). _{B n = d 1 C n aE} ··· (7)

In the imaging state shown in FIG. 5C, the intensity of light incident on the flat sensor 9 is expressed by the following equation (8). C _n = d ₂ bE (8)

From the equations (6), (7) and (8), the amplitude of the composite wave is expressed as the following equation (9).

(Equation 5) Assuming that the distance between the semiconductor laser 3 as a light source and the target object 6 and the distance between the target object 6 and the plane sensor 9 are L and the light speed is C, the phase delay φ _n is given by the following equation (11). Is represented by φ _n = ωL / C (11)

From the above equations (9) and (11), the distance L is expressed by the following three types of image data An, Bn and Cn as in the following equation (12).

(Equation 6)Therefore, to calculate the distance to the target object 6, three types
Only need to detect the image data An, Bn, Cn
Become. Equation (12) shows the reflection coefficient C of the target object 6 _n, Optics
Constant d due to the system₁, D_Two, And the external light intensity e
Since there is no object,
Can acquire distance information even when imaged under external light 4d.
it can.

According to the above-described first embodiment, the following effects can be obtained. (A) Since both the number of times that the illumination light 4a and the reference light 4c emitted from the semiconductor laser 3 pass through the half mirror 10 is one, the reduction of the light amounts of the reflected light 4b and the reference light 4c received by the flat sensor 9 can be reduced. It becomes possible to suppress. (B) A phase distribution corresponding to the distance to the object 6 can be obtained without the need for expensive and large-sized means such as a crystal light intensity demodulator and an image intensifier which have been conventionally used as a means for demodulating light. Therefore, an inexpensive and compact three-dimensional shape measuring apparatus can be provided. (C) Since the optical filter 8 for selectively transmitting the light of the light source is provided on the front surface of the flat sensor 9, if infrared light or ultraviolet light is used as the light source, the error due to the influence of the external light 4 d is small, and the accuracy is high. A three-dimensional shape can be measured. (D) Since a phase distribution corresponding to the distance to the target object 6 can be measured as a voltage value, a three-dimensional shape can be easily measured. (E) Both a distance image and a luminance image can be obtained by one plane sensor 9, and since these two images have one-to-one correspondence with pixels, image processing of the luminance image using the distance image can be performed. It can be done easily. (F) By capturing three images with different illumination conditions, distance information can be obtained even if the target object 6 having any reflectance distribution is captured under any external light 4d. . (G) Since both the distance image and the luminance image are obtained, for example, it is easy to create a composite image in which the image captured in the studio is combined with the architectural image and the background image, and to cut out an object image from the composite image. .

FIG. 7 shows a shape measuring apparatus according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that the target object 6 is replaced with the half mirror 10.
The optical path of the illumination light 4a applied to the light (shown by a dotted line in the figure).
The reflection mirror 15 is arranged at a position deviated from the above, and the other configuration is the same as that of the first embodiment. According to the second embodiment, since the amount of the reflected light 4b incident on the flat sensor 9 is not reduced by half by the half mirror 10, the output signal of the flat sensor 9 increases, and the S / N ratio increases.
The ratio improves.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the above-described embodiment, a semiconductor laser is used as a light source. However, since a coherent light is not required in principle, a general light source, for example, a xenon lamp or a strobe can be used. . Further, in the above embodiment, the reflected light 4b and the reference light 4c are received by the common plane sensor 9, but the reflected light 4b is received by the plane sensor and the reference light 4c is set to 1
One or a plurality of light receiving elements may receive light and output a combined signal obtained by combining respective output signals. In this case, it is also possible to omit the reflection member such as a half mirror and directly take in the emitted light 4a as reference light. Although the half mirror 10 is used in the first embodiment, a beam splitter that transmits and reflects incident light at a predetermined ratio may be used.

[0038]

As described above, according to the present invention,
Since the amount of light emitted from the light emitting means and the amount of light reflected from the object can be suppressed from being reduced by the reflecting member, the light use efficiency is increased. Further, since the distance to the object is measured based on the phase difference between the emitted light and the reflected light, there is no need to use an expensive modulator / demodulator or an expensive and large image intensifier. An inexpensive shape measuring device and shape measuring method can be provided. Further, by performing a correction for removing an external component such as a difference in reflectance on the surface of the object and calculating the distance to the object, it is possible to accurately measure the distance to the object.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a three-dimensional shape measuring apparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a pixel circuit included in the flat sensor according to the first embodiment;

FIGS. 3A to 3D are waveform diagrams for explaining the operation of the flat sensor according to the first embodiment;

FIGS. 4A and 4B are diagrams showing, by a computer simulation, that the amplitude of the combined light changes due to the phase delay of the reflected light.

FIGS. 5A, 5B, and 5C are diagrams for explaining the operation of the three-dimensional shape measuring apparatus according to the first embodiment.

FIG. 6 is a flowchart for explaining the operation of the three-dimensional shape measuring apparatus according to the first embodiment;

FIG. 7 is a configuration diagram of a three-dimensional shape measuring apparatus according to a second embodiment of the present invention.

FIG. 8 is a configuration diagram of a conventional three-dimensional shape measuring apparatus.

FIG. 9 is a configuration diagram of a conventional three-dimensional shape measuring apparatus.

FIG. 10 is a configuration diagram of a conventional three-dimensional shape measuring apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 3D shape measuring apparatus 2 Modulation signal generator 3 Semiconductor laser 4a Illumination light 4b Reflected light 4c Reference light 5 Projection lens 6 Target object 7 Imaging lens 8 Optical filter 9 Planar sensor 10 Half mirror 11A, 11B Shutter 12 Image memory 13 Distance calculation unit 14 CPU 14a Semiconductor laser monitor output line 15 Reflection mirror 90 Photodiode 91A First bypass circuit switching unit 91B Second bypass circuit switching unit 92 High pass filter (HPF) 93 Peak hold circuit 93a Comparator 93b Diode 93c Capacitor 94 Current conversion circuit 95 Bypass wiring 96 Switch 97 Charge storage circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Abe 430 Sakai, Nakagawa-cho, Ashigarakami-gun, Kanagawa Green Tech Nakai F-term in Fuji Xerox Co., Ltd. 2F064 AA09 CC01 FF02 GG12 GG22 HH03 HH08 JJ06 2F065 AA06 AA53 DD02 DD04 EE03 FF42 FF52 GG04 GG06 JJ03 JJ18 JJ26 LL00 LL04 LL21 LL30 LL53 NN08 NN17 QQ00 QQ02 QQ24 QQ25 QQ33

Claims (7)

[Claims] 1. A shape measurement for emitting outgoing light intensity-modulated at a predetermined frequency toward an object and measuring a distance to the object based on a phase difference between reflected light from the object and the outgoing light. In the device, a light emitting unit that emits the emitted light whose intensity is modulated at the predetermined frequency toward the object, a reflecting member that reflects the emitted light emitted from the light emitting unit in a predetermined direction, A combined detection signal that receives the reflected light from the object and the outgoing light from the reflecting member, and reflects the phase difference by combining them; and the reflected light reflected by the object by emitting the outgoing light. Detecting means for receiving the reflected light detection signal and receiving the emitted light from the reflection member and outputting a reference light detection signal; and outputting the reference light detection signal to the combined detection signal, the reflected light detection signal and the reference light detection signal. And a calculating means for calculating the distance by performing a correction for removing an external component such as a difference in reflectance of the surface of the object based on the calculated value. 2. The detector according to claim 1, wherein said detector is provided in said predetermined direction, and outputs a detection signal according to the light intensity of the incident light; an optical path between said object and said detector; Each provided on an optical path between a reflecting member and the detector,
Two shutter means for opening or closing the optical path by opening and closing operation, and control for outputting the combined detection signal, the reflected light detection signal and the reference light detection signal from the detector by opening and closing control of the two shutter means. The shape measuring apparatus according to claim 1, comprising: 3. The detection means outputs an amplitude detection signal indicating an amplitude of a combined light of the reflected light and the output light as the combined detection signal reflecting the phase difference, and outputs the amplitude detection signal from the object by external light. Outputting a light quantity detection signal indicating the light quantity of the steady reflected light as a steady reflected light detection signal of the; andthe calculating means calculates the distance based on the amplitude detection signal, and calculates the distance of the object based on the light quantity detection signal. The shape measuring device according to claim 1, wherein the shape measuring device has a configuration for calculating luminance. 4. The detector according to claim 1, wherein the detector outputs a detection signal corresponding to the light intensity of the incident light, and is provided on a front surface of the detector, and selectively transmits light from the reflecting member or the object. The shape measuring apparatus according to claim 1, further comprising an optical filter configured to perform the measurement. 5. The detecting means includes a plurality of detecting elements arranged two-dimensionally and outputting a detection signal according to the light intensity of incident light, and the calculating means includes a plurality of detecting elements up to a plurality of points on the object. The shape measuring apparatus according to claim 1, wherein the distance is calculated. 6. A shape measurement for emitting outgoing light intensity-modulated at a predetermined frequency toward an object and measuring a distance to the object based on a phase difference between reflected light from the object and the outgoing light. An apparatus, wherein: a light emitting unit that emits the emitted light whose intensity is modulated at the predetermined frequency toward the object; receives the reflected light and the emitted light from the object; A combined detection signal in which the phase difference is reflected, a reflected light detection signal that receives reflected light reflected by the object by emitting the emitted light, and a detection unit that receives the emitted light and outputs a reference light detection signal, Calculating means for calculating the distance by performing a correction to remove an external component such as a difference in reflectance of the object surface based on the combined detection signal, the reflected light detection signal and the reference light detection signal. That Shape measuring device according to symptoms. 7. A shape measurement for emitting outgoing light intensity-modulated at a predetermined frequency toward an object and measuring a distance to the object based on a phase difference between reflected light from the object and the outgoing light. In the method, the emission light intensity-modulated at the predetermined frequency is emitted toward the object, the reflected light and the emission light are detected, and the combined detection signal reflects the phase difference by combining them. Converting, emitting the emitted light toward the object,
A first step of detecting reflected light reflected by the object and converting the reflected light into a reflected light detection signal, detecting the emitted light and converting it into a reference light detection signal, the combined detection signal, the reflected light detection signal and A second step of performing a correction to remove an external component such as a difference in reflectance of the object surface based on the reference light detection signal and calculating the distance.