JPH10239023A - Three-dimensional measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional measuring device capable of making three-dimensional measurement with high accuracy even when an object to be measured is moved. SOLUTION: A laser beam serving as measurement light is scanned at a high speed in the horizontal direction by a polygon mirror 36, it is scanned in the vertical direction by a galvano-mirror 38, it is transferred via the image guide 31 of an endoscope 2, and it is projected to an object 50 via a projection lens 45. The reflected light forms an image on the tip face of an image guide 32 with an objective lens 46, the image is transferred and detected by tape-like fiber bundles 48(i) and photoelectric transfer elements 49(i) arranged to face them at their outgoing ends having light detecting functions in the vertical direction only via an image forming lens 47 from the rear end face. The three- dimensional position is calculated via a laser spot position detecting circuit 54 and a distance calculating circuit 56, and three-dimensional measurement is made with high accuracy by the high-speed scanning of the laser beam even when the measured object is moved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional measuring apparatus for projecting a scanning spot light onto a subject and performing three-dimensional measurement on the subject.

[0002]

2. Description of the Related Art Conventionally, spot light or light slit light is projected as a measuring light on a measuring object, and how the light shifts due to unevenness of the measuring object is detected by an imaging means such as a television camera. , Three-dimensional measurement was performed based on the deviation amount.

However, this method can measure only one spot light or one slit light per one frame or one field image of the television camera, and cannot measure the whole surface of the object to be measured in real time. Was.

On the other hand, as in US Patent 4,349,277, a method of spatially and temporally encoding measurement light and simultaneously measuring a plurality of locations has been proposed, but the encoding is realized by the number N of light intensity levels. Therefore, in order to generate many code patterns, measurement light beams having different intensities have to be projected many times, which takes time for measurement.

[0005] Further, as in Japanese Patent Publication No. 8-16606,
Projecting on the measurement object while scanning the blinking line light,
An apparatus for detecting the amount of shift at high speed with a plurality of light receiving elements is disclosed.

[0006]

However, even in this case, scanning must be performed eight times in order to obtain a resolution of, for example, 256 lines of light. And it was not practical.

(Object of the Invention) The present invention has been made in view of the above points, and has as its object to provide a three-dimensional measurement apparatus capable of performing three-dimensional measurement with high accuracy even when a measurement object moves. This is the first purpose.

It is a second object of the present invention to provide a three-dimensional measuring apparatus capable of easily increasing the resolution of measurement and performing three-dimensional measurement with a simple configuration.
It is a third object of the present invention to provide a three-dimensional measuring device capable of measuring a wide range of spot positions with a small number of light receiving elements.

[0009]

A scanning spot light projecting means for scanning a spot light and projecting the object on an object, an image forming means for forming an image of the spot light reflected by the object, and an image forming method for the object by the image forming means. Light position detecting means for detecting the position of the spot light with respect to the two-dimensional measurement area by a light receiving element arranged one-dimensionally at an image position; an output of the light position detecting means, a scanning position of the spot light and a scanning spot light; By providing position calculating means for calculating the position of the spot light on the subject from the position of the projecting means and the light position detecting means,
With a simple configuration, and even when the object to be measured is moving, if the scanning spot light is performed at high speed, by using the outputs of the photoelectric conversion elements arranged one-dimensionally,
Three-dimensional measurement can be performed accurately in a short time.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIGS. 1 and 2 relate to a first embodiment of the present invention, and FIG. 1 shows a first embodiment of a three-dimensional measuring apparatus of the present invention.
2 shows an overall configuration of a three-dimensional measurement endoscope apparatus according to the embodiment, and FIG. 2 shows a principle diagram of distance measurement according to the embodiment.

As shown in FIG. 1, a three-dimensional measurement endoscope apparatus 1 according to a first embodiment of the present invention includes an endoscope 2 having an insertion portion 6 inserted into a lumen, and A light source unit 3 for supplying illumination light with visible light to the endoscope 2 and a three-dimensional measurement for supplying measurement light to the endoscope 2 and receiving reflected light of the measurement light from the subject to perform three-dimensional measurement It has a unit 4 and a display 5 for displaying a three-dimensionally measured subject image.

The endoscope 2 has a flexible insertion portion 6 inserted into the lumen, an operation portion 7 provided at the rear end of the insertion portion 6, and an operation portion 7 provided at the rear end of the operation portion 7. Eyepiece 8
The universal cable 9 has a first connector detachable from the light source unit 3 and a second connector detachable from the three-dimensional measurement unit 4 at an end of the universal cable 9. A connector is provided.

A lamp driving circuit 13 is provided in the light source unit 3.
A white light emitted from the lamp 14 is condensed by a condenser lens 15 and supplied to a light incident end of a light guide 16 for transmitting illumination light. This white light is transmitted from the universal cable 9, the operation unit 7,
The light is transmitted by the illumination light transmission light guide 16 inserted through the insertion portion 6, is further expanded from the distal end surface fixed to the distal end portion 17 of the insertion portion 6 via the observation illumination lens 18, and is emitted. To illuminate the subject side such as the affected part.

The hard tip 17 has an observation illumination lens 1
An observation window is provided adjacent to the illumination window to which 8 is attached, and an observation objective lens 19 is attached to the observation window, and an optical image of the illuminated subject is formed at the image forming position. The distal end surface of the observation image guide 21 is arranged at this image forming position, and the optical image is transmitted to the rear end surface by the observation image guide 21.

An eyepiece 22 is provided in the eyepiece 8 facing the rear end face, and the optical image transmitted by the observation image guide 21 through the eyepiece 22 can be observed with the naked eye.

The endoscope 2 has an insertion portion 6, an operating portion 7, and a measuring light transmission image guide 31 and a shape measurement image guide 32 in the universal cable 9 similarly to the illumination light transmission light guide 16. Are inserted, and the light incident end and the light exit end of the end of the universal cable 9 are connected to the three-dimensional measurement unit 4. The two image guides 31 for measuring light transmission and the image guide 32 for shape measurement are formed of, for example, image guides having the same characteristics.

The three-dimensional measuring unit 4 has a laser beam scanning unit 30 for scanning a laser beam. The laser beam scanning unit 30 has a laser 34 driven to emit light by a laser driving circuit 33. The light is reflected by a polygon mirror 36 driven to rotate by a polygon drive motor 35, and the reflected light is further reflected by a galvano mirror 38 rotated by a galvanomirror drive circuit 37, and then passes through a lens 39 for measuring light transmission. Image Guide 3
No. 1 is incident on the light incident end.

The polygon mirror 36 has a multiplicity of mirror surfaces with its side parallel to the rotation axis of the polygon drive motor 35 being a regular polyhedron. The polygon mirror 36 is rotated by the polygon drive motor 35 so that a laser beam is measured in a horizontal plane. An angle scan corresponding to the horizontal width of the end face of the transmission image guide 31 is performed.

A polygon position encoder 40 is attached to the rotation axis of the polygon drive motor 35.
It is used to detect the horizontal scanning angle (scanning position) of the laser beam.

The galvanomirror 38 is reciprocally rotated within a predetermined angle range when a driving signal such as a triangular wave or a staircase wave is applied by the galvanomirror driving circuit 37. In this case, the galvanomirror 38 is rotated around an axis included in a plane parallel to the horizontal plane.

The light incident on the galvanometer mirror 38 is reflected, and the direction of the reflection is scanned in the vertical direction. The laser light scanned in the horizontal and vertical directions in this manner is incident by the condenser lens 39 so as to scan the light incident surface of the image guide 31 for measurement light transmission in the horizontal and vertical directions.

In this case, the polygon mirror 36 causes a laser spot to scan a line in a horizontal direction over the number of fibers passing through the diameter of the image guide 31 for transmission of measurement light on one mirror surface thereof. It is moved vertically by the galvanomirror 38 by the fiber pitch in the vertical direction.

After scanning the entire area of the light incident surface of the measuring light transmission image guide 31 in the horizontal and vertical directions, the galvanometer mirror 38 is rotated in the opposite direction, and is moved in one direction in the horizontal direction. , But scan in the vertical direction in reverse (scan back and forth).

The distal end face of the measuring light transmission image guide 31 is attached to the distal end portion 17, and a measuring light projecting lens 45 is provided to face the distal end face, and transmitted by the measuring light projecting lens 45. The laser spot is projected on the object 50 side, and the scanning of the projected spot corresponds to the scanning at the light incident end.

That is, the object 50 scans in a certain direction corresponding to the horizontal scanning at the light incident end. To simplify the explanation, the horizontal scanning at the light entrance end
It is assumed that the object is also scanned in the horizontal direction.

The measuring light projecting lens 45 is provided at the tip 17.
Is provided adjacent to the object, and the position of the laser spot projected on the surface of the subject 50 by the measuring light projecting lens 45 is arranged at the image forming position. Image guide 3 for shape measurement
An image is formed on the front end surface of the image forming apparatus 2.

The shape measuring image guide 3
2, the light is transmitted to the light emitting end on the rear end face. An imaging lens 47 is arranged opposite to the light emitting end, and the imaging lens 47 forms an image on a tape-like fiber bundle array 48 whose end face is arranged at the position of the imaging plane.

This tape-like fiber bundle array 48 has an array structure in which a plurality of tape-like fiber bundles 48 (1) to 48 (n) are stacked, and each of the tape-like fiber bundles 48 (i).
(I = 1 to n) is, for example, an image guide 3 for measuring light transmission.
One end of the number of fibers equal to or greater than the number of fibers passing through the diameter of one (or the image guide 32 for shape measurement) is hardened in a tape shape, and the other end is formed into a bundled shape.

At one end serving as a light incident end, these tape-like fiber bundles 48 (1) to 48 (n) have a structure in which they are arranged in a stack, for example, a square end surface, and the other end serving as a light emitting end. The sides are bundled round and separated from each other, and the photoelectric conversion element 49 is opposed to each end face bundled round.
(I) are arranged in an array, respectively, and light emitted from each end face is respectively detected.

The distance of each part of the subject is measured by the principle of the distance measurement of triangulation. In this embodiment, if the position of the reflected light is detected along one direction, the position of the subject corresponding to the detection is detected. , And a tape-like fiber bundle array 48 having a function of detecting light in a direction perpendicular to one direction is used. This principle will be described later with reference to FIG. 2A for a simple example and FIG. 2B for a more general case.

In this embodiment, if the laser spot scanned through the measuring light projecting lens 45 by the rotation of the polygon mirror 36 is, for example, in the horizontal direction, the laser spot is moved in the horizontal direction in the image guide 32 for shape measurement. Each of the tape-like fiber bundles 48 (i) in which fibers are arranged so that the light incident end thereof spreads in a tape shape so as to have a function of light detection only in a direction parallel to the above is laminated in a direction perpendicular to the horizontal direction. , The position is detected in the vertical direction.

After the outputs of the photoelectric conversion elements 49 (i) are amplified by the amplifiers 51 (i), they are input to the signal processing circuit 53 via the changeover switch 52 which is sequentially switched at a high speed, and further detects the laser spot position. Is input to the laser spot position detection detection circuit 54.

The changeover switch 52 includes a switch control circuit 55
The switch control circuit 54 sequentially switches the changeover switch 52 at a high speed.
A selection signal indicating whether (i) is selected is output to the laser spot position detection circuit 54. Laser spot position detection circuit 5
4 detects the laser spot position with reference to the selection signal.

In the present embodiment, instead of providing n signal processing circuits 53 and performing parallel processing, the switching is performed at high speed using the changeover switch 52, so that one signal processing circuit 53 can be used at each horizontal scanning position. , Which photoelectric conversion element 4
At 9 (i), detection processing is performed to determine whether or not light has been detected. The output of the n comparators may be used to detect which light detection element 49 (i) has detected light at each horizontal scanning position.

The output of the laser spot position detection circuit 54 is input to a distance calculation circuit 56 for calculating a distance.
Further, position information of horizontal scanning by the polygon position encoder 40 is input to the distance calculation circuit 56.

The distance calculation circuit 56 outputs the output of the laser spot position detection circuit 54 and the polygon position encoder 4
The information corresponding to the position information of the horizontal scanning by 0 and the position information of the vertical scanning direction by the galvanometer mirror 38 (the vertical scanning position can be determined if there is no error by the magnitude of the driving signal by the galvanometer mirror driving circuit 37. The timing at which the drive signal is output is also known.), And the distance from the tip surface of the tip portion 17 to each position of the subject 50 is calculated.

The output of the distance calculation circuit 56 is input to a display control circuit 57, where processing or control of three-dimensional display is performed, and three-dimensional display data is output.

The output of the display control circuit 57 is temporarily stored in a three-dimensional shape memory 58, and a video signal is synthesized by a video signal synthesizing circuit 59, and the three-dimensional shape is displayed on the display 5.

(Operation) Next, the operation of the thus configured three-dimensional shape measuring endoscope apparatus 1 will be described. Illumination light from the lamp 14 is transmitted by the illumination light transmission light guide 16, emitted from the distal end surface through the illumination lens 18 to the subject side, and illuminates the subject side with white light. The illuminated object is image guide 2 by the objective lens 19.
An image is formed on the distal end surface of the lens 1, and the image can be magnified and observed through the eyepiece 22.

The laser light of the laser 34 is scanned by the polygon mirror 36 in the horizontal direction, and is scanned by the galvano mirror 38 in the vertical direction, which is slower than the scanning in the horizontal direction. That is, a laser beam scans a two-dimensional area like raster scanning on a television screen, and this scanning light is incident on the light incident end of the measurement light transmission image guide 31 by the condenser lens 39.

Then, the laser beam is transmitted by the fiber forming the image guide 31 for transmitting the measuring light into which the laser beam is incident, and the measuring light projecting lens 4 is further transmitted from the tip end surface.
5, the light is projected or projected on the subject 50 side. The projected laser spot is two-dimensionally scanned in such a manner that the object plane is sequentially scanned in a horizontal line at a high speed, for example, and a position slightly shifted in the vertical direction is scanned at a high speed in a parallel line after scanning one line. Scanning.

The laser spot reflected by the object at each scanning position forms an image on the distal end surface of the image guide 32 for shape measurement by the object lens 46 for shape measurement. The laser spot image formed on the front end surface is transmitted to the rear end surface of the image guide 32, and is detected by the tape-like fiber bundle array 48 from the end surface via the imaging lens 47.

Each of the tape-like fiber bundles 48 (i) has a large number of fibers arranged at the end face on the incident side, for example, in the vertical direction, and the light detected by these fiber arrays is one.
It is detected by the two photoelectric conversion elements 49 (i) and photoelectrically converted. After the photoelectrically converted signal is amplified, the signal is input to a laser spot position detection circuit 54 via a changeover switch 52 which is switched at a high speed, and the spot position is detected.

The output of the spot position detection circuit 54 is input to a distance calculation circuit 56, and the distance to each part of the subject is calculated using information on the detected spot position and the like. The calculated distance information is input to the display control circuit 57 to generate image data to be displayed in a three-dimensional shape. Then, it is stored in the three-dimensional memory 58, converted into a video signal, and displayed on the display 5 in a three-dimensional manner.

According to this embodiment, the scanning means for two-dimensionally scanning the light beam at high speed, and the reflected light of the light spot projected on each part of the object under the scanning is reflected on the image forming surface. Since the position of each part is calculated by detecting with the light position detecting means formed by the photoelectric conversion elements arranged one-dimensionally with respect to the two-dimensional measurement target area, the movement is simple and the movement is simple. Even for a certain subject, three-dimensional measurement can be performed with high accuracy. In addition, if the number of fibers such as the image guides 31 and 32 is increased, the resolution of measurement can be easily improved.

Further, the number of photoelectric conversion elements required for measurement for a two-dimensionally spread measurement target only needs to correspond to the resolution along one direction. In addition to being able to cover as few as possible, it can also be detected at high speed.

Next, the principle of measuring the three-dimensional position will be described below with reference to FIG. FIG. 2A shows a structure near a shape measuring objective lens 46 adjacent to the measuring light projecting lens 45. A laser beam for horizontal scanning is transmitted by the image guide 31 in a direction perpendicular to the paper surface including the optical axes of the lenses 45 and 46, and is projected from the front end surface through the lens 45 to the subject side.

When the laser beam is in the plane of the paper as shown, the light is emitted from the point P1 on the object plane H1 or the object plane H.
The image is projected on the point P1 'or P2' on the distal end surface of the image guide 32 by the lens 46.

Therefore, even if the distance to the object surface changes, if the length from the optical axis of the lens 46 to the point P1 'or P2' is detected, the distance to the object can be calculated from the data of these optical systems. Can be calculated. That is, the position of the image guide 32 in the horizontal direction may be detected in FIG. For this reason, the tape-shaped fiber bundle 48 (i) is
(A) Lamination may be performed in a direction parallel to the scanning direction of the laser beam. In the present embodiment, such an arrangement is employed.

Although the description has been made on the assumption that the laser beam is located in the plane of the paper, even if the laser beam deviates from the plane of the paper, if the amount of deviation from the plane of the paper is known, the position can be measured similarly. Next, the generalization principle of the three-dimensional position is shown in FIG.
This will be described with reference to FIG.

In the three-dimensional measurement endoscope apparatus 1 of the present embodiment, the point of the light applied to the object surface on the original image plane corresponding to the spot position is known, and the image pickup system (measurement light detection optical system) ) Has a resolution only in the horizontal direction because an image is picked up by a single image sensor for each vertical line.

Now, a virtual image plane of the fiber 102 (specifically, the fiber of the image guide 31 for transmitting the measuring light) forming the measuring light projecting optical system (abbreviated simply as the light projecting system) 101 and the measuring light The virtual image plane of the fiber array 104 (specifically, the fiber end surface of the tape-like fiber bundle array 48) forming the detection optical system (abbreviated as an imaging system) 103 is parallel, and the horizontal direction is Ex and the vertical direction is Ex. Ey, the lenses 105 and 106 of the light projecting system 101 and the imaging system 103
(Specifically, it is assumed that the projection lens 45 and the imaging lens 47) have the same optical axis direction Ez.

The geometric origin is defined as the optical center F (0, 0, 0) of the projection lens 105. Now, the light projecting system starts at the point Q (Xj, Yk,
Consider a situation in which a spot P (Xp, Yp, Zp) hit by the light emitted from Zo) on the object plane 107 enters the i-th fiber array in the imaging system 103. Since the projected beam is on the straight line QF connecting Q and F, the condition that the point satisfies is x / Xj = y / Yk = z / Zo (Equation 1) where Xj and Yk are the laser beam of the measurement light source. Is determined by the irradiation direction. Therefore, the value is determined by the rotation angle of the polygon mirror 36 and the rotation angle of the galvanomirror 38 for scanning the laser beam in each direction.

Zo is defined by the virtual distance between the optical center F of the light projecting system and the image plane of the light projecting system. Here, Zo
Can be considered fixed. Next, the light beam imaged on the i-th fiber row is included in the plane S including the fiber row and the optical center M (Xm, Ym, Zm) of the imaging lens 106.
Here, the angle between the direction of the optical axis and the surface S is φ. The equation of the surface S is as follows: Xm−x = (Zm−z) tan φ (Equation 2) Here, the angle φ is the virtual distance between the lens 106 and the imaging surface, and the fiber rows h and i through which the main axis of the lens 106 passes.
Can be calculated from the deviation. Therefore, in the three-dimensional shape measuring optical system constituted by the tape-shaped fiber bundle array 48 forming the fiber array 104, the angle between the incident fiber array and the main axis of the optical system must be determined in advance from the arrangement of the optical system. Good.

The spot P (Xp, Y) on the object surface 107
Since p and Zp are on the straight line QF and are included in the surface S, the above two conditions are satisfied. Therefore, Xp / Xj = Yp / Yk = Zp / Zo (Equation 3) Xm-Xp = (Zm- Zp) tanφ (Equation 4).

By solving this, Xm− (Zp / Zo) · Xj = (Zm−Zp) tanφ (Equation 5) Zp (tanφ−Xj / Zo) = Zm · tanφ−Xm (Equation 6) Zp = (Zm · tanφ−Xm) / (tanφ−Xj / Zo) (Equation 7) Xp = (Zp / Zo) · Xj = (Zm · tanφ−Xm) / (Zo · tanφ−Xl) · X5 = (Zm · tanφ−Xm) ) / ((Zo / Xj) · tan φ-1) (Equation 8) Yp = Zp / Zo · Yk = (Zm · tanφ-Xm) / (Zo · tanφ-Xj) · Yk (Equation 9) The coordinates could be determined.

That is, the three-dimensional information from the position (k, j) of the light incident on the light receiving element for detecting the light of the i-th fiber row is given by (Equation 7, 8, and 9). . Here, the operation of scanning the laser beam and the operation of detection by the tape-like fiber bundle array 48 need to be completely synchronized.

For this purpose, the polygon position encoder 40
The laser spot position detection circuit 54 detects the output at the output.
Similarly, if the position of the successively scanned beam and the position of the tape-shaped fiber bundle on which the beam is incident are specified, the shape of the object surface 107 can be measured by associating it.

FIG. 3 shows a main part of a modification of the first embodiment. In this modification, each tape-like fiber bundle 48
(I) A diffusion plate 61 is attached to the end face on the incident side. In FIG. 3A, the diffusion plate 61 and the end face of the tape-like fiber bundle 48 (i) are shown as being separated from each other, but actually, they are attached to the end face as shown in the plan view of FIG. I have. Although not shown, a metal thin film or the like is vapor-deposited on the surface of the diffusion plate 61 that is in contact with the diffusion plate, thereby preventing light from leaking into the adjacent diffusion plate.

By attaching the diffusion plate 61 to the end surface of the tape-like fiber 48 (i) in this way, the structure shown in FIG.
As shown in FIG.
Even if the light does not enter the core portion 62 of (i) but enters the cladding portion 63, a part of the light is diffused and enters the core portion 62, so that the incident light can be more reliably emitted. Can be detected.

FIG. 4 shows a modification of FIG. In FIG. 3A, the diffusion plate 61 is provided for each end face of one row of the tape-shaped fiber bundle 48 (i), but in FIG. 4, the diffusion plate 61 is provided for a plurality of rows (two rows in a specific example). I have. In this case, substantially the same operation and effect can be obtained. In this case, the diffused light partially leaks into the adjacent tape-shaped fiber bundle. However, if the diffusion plate 61 is thin, the influence is small.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
2 shows a main part of the embodiment. In this embodiment, a thin glass array 66 with a reflection coat is used instead of the tape-like fiber bundle array 48. The thin glass array with reflection coat 66 is a thin glass with reflection coat 67 (i).
Are stacked in n layers.

As shown in FIG. 6, each of the thin glass plates 67 (i) provided with a reflection coat is provided with a reflection coat 69 serving as a reflection layer on both sides of a thin transparent glass 68, and these are n sheets in the thickness direction. , And laminated.

The incident light incident on one end face is transmitted to the other end side while being reflected by the reflection layer 69, and the outgoing light emitted from the other end is, as shown in FIG. The light is not condensed in the horizontal direction by the lens 70, but is condensed in the vertical direction, and is arranged so as to face each other, and is received by the photoelectric conversion elements 49 (i) forming the photoelectric conversion element array 49.

That is, the thin glass 67 with each reflection coat
(I) is different from the direction D when the light spot is projected at a high speed in one direction (more specifically, in a direction (D)) as in the case of the tape-shaped fiber bundle 48 (i). , Preferably in a direction orthogonal to the direction). Other configurations are the same as those of the first embodiment. The effect of the present embodiment is almost the same as the case where the tape-like fiber bundle array 48 of the first embodiment is used.

(Third Embodiment) FIG. 7 shows a third embodiment of the present invention.
2 shows a main part of the embodiment. In this embodiment, a slit-like photoelectric conversion element array 71 is employed instead of the tape-like fiber bundle array 48 and the photoelectric conversion elements 49 (i) arranged in an array in the first embodiment.
That is, the photoelectric conversion element array 71 shown in FIG. 7 is arranged at the image plane position of the image forming lens 47 in FIG.

The photoelectric conversion element array 71 has an elongated light receiving surface (that is, a light receiving surface having a function of detecting light only in one direction such as a vertical direction) 72 (i).
Are arranged at a predetermined pitch. The pitch is determined by the imaging lens 47 and the shape measurement image guide 3.
When the two fiber end faces are arranged on the image forming plane where the image is formed, it is conceivable as a specific value to make the pitch substantially equal to the horizontal pitch of the fiber image.

A signal line 73 (i) connected to each photoelectric conversion element 72 (i) is connected to the amplifier 51 (i) of FIG.
Each of the photoelectrically converted signals is amplified by the amplifier 51 (i). Other configurations are the same as those of the first embodiment. The effects of this embodiment are almost the same as those of the first embodiment.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth shown in FIG.
In the three-dimensional measurement endoscope device 74 of the embodiment, the endoscope 2 in FIG. 1 does not include the observation objective lens 19 and the observation image guide 21, and the image formed by the shape measurement objective lens 46 is a half mirror. The distal end surface of the image guide 32 for shape measurement is arranged on the transmission side via 75a, and the CCD 75b as an image sensor is arranged on the reflection side to form an image. Each point of the image formed on the distal end surface of the image guide 32 for shape measurement and the image formed on the CCD 75b correspond to one body.

The half mirror 75a may be an ordinary half mirror, but transmits a laser beam wavelength set in an infrared wavelength range or the like used for measurement, and selectively reflects other visible light wavelength ranges. If a dichroic mirror having characteristics is used, measurement light and illumination light can be used effectively, and sensitivity and S / N can be further improved. Further, a color error caused by the reflection by the dichroic mirror may be corrected by a color correction circuit so as to be in a state closer to a natural image.

Since the image guide 21 is not provided as described above, the eyepiece 8 is not provided in the endoscope 2 'in the present embodiment. This CC located at the tip 17
A signal line 75c is connected to D75b.
c is inserted through the insertion section 6, the operation section 7, and the universal cable 9, and is connected to an electrical contact provided on the connector.

This electric contact is a three-dimensional shape measuring unit 4
It is input to the video signal circuit 76 via the electrical contact receiver provided on the side, and a color video signal for normal observation is generated,
The video signal is input to the video signal synthesis circuit 59. The color image is combined with the three-dimensional shape image data from the three-dimensional shape memory 58 so that a colorized bird's-eye view is displayed on the display 5.

Further, in this embodiment, the laser beam scanning means 30 "is different from the laser beam scanning means 30 in FIG.
Polygon mirror 3 for horizontal scanning of laser light
A high-speed scan mirror 77a is used in place of 6, and the high-speed scan mirror 77a is attached to a high-speed scan mirror driving device 77c via a support 77b.

This high-speed scan mirror driving device 77c
Are reciprocally rotated and oscillated at high speed by a drive signal from the high-speed scan mirror driving circuit 77d,
The laser beam a is reciprocally oscillated in a horizontal plane to scan the laser beam in the horizontal direction.

The high-speed scan mirror driving circuit 7
7d and the galvanometer mirror drive circuit 37
8 and outputs the position information of the high-speed scan mirror 77 a and the position information of the galvano mirror 38 to the distance calculation circuit 56. Then, the distance calculation circuit 56 uses the output of the laser spot position detection circuit 54 and the position information thereof,
Calculate the distance.

In this embodiment, the high-speed scan mirror 77
The position information a and the position information of the galvanomirror 38 are output to the distance calculation circuit 56 and are used for distance calculation, thereby correcting distortion and the like of an optical system used for distance measurement, thereby achieving more accurate distance measurement. (In the first embodiment, only the position information of the polygon mirror 36 that performs horizontal scanning is used, and the position information of the galvanomirror 38 that performs vertical scanning is fixed by the galvanomirror driving circuit 37. Is set in advance so that there is no error or it can be ignored).

In FIG. 1, the output of the amplifier 51 (i) is input to the laser spot position detecting circuit 54 through the signal processing circuit 53 via the changeover switch 52, but in this embodiment, the amplifier 51 (i) is used. The output of (i) is input to a laser spot position detection circuit 54 via a signal processing circuit 53 'for performing parallel processing. The signal processing circuit 53 'detects the position of the tape-like fiber bundle 48 (i) where the light spot image is incident by parallel processing.

In the first embodiment, the subject 50 illuminated with white light is imaged on the distal end surface of the observation image guide 21 by the observation objective lens 19, so that it can be observed with the naked eye. In the present embodiment, the shape measurement objective lens 46 is used for both observation and shape measurement. Other operations are almost the same as those of the first embodiment.

According to the present embodiment, the observing objective lens 19 and the observing image guide 21 do not need to be used, so that there is an advantage that the insertion section 6 can be made thinner. The observation image and the measurement image are shared by a common objective lens 46.
Therefore, both images can be easily synthesized. Other effects are almost the same as those of the first embodiment.

(Fifth Embodiment) FIG. 9 shows a fifth embodiment of the present invention.
1 shows an overall configuration of a three-dimensional measurement endoscope apparatus 80 according to the embodiment. In the present embodiment, the spot beam of the semiconductor laser light source is scanned in the horizontal and vertical directions, and the spot position of the beam on the object plane is connected by a fiber so that one light receiving element corresponds to one line of the image. In a device having a system and measuring height information of an object based on the principle of triangulation, scanning of a spot beam light source is performed using an acousto-optic deflector, and a signal of a driving power supply of the acousto-optic deflector is used. The horizontal and vertical positions of the beam are obtained.

In this embodiment, basically, a laser beam scanning unit 30 ′ having a configuration different from that of the laser beam scanning unit 30 of the three-dimensional measuring unit 4 in the embodiment of FIG. 1 is used.

That is, the laser beam of the semiconductor laser 82 driven to emit light by the laser drive circuit 81 is diffracted in the horizontal direction by the first acousto-optic deflector (abbreviated as AOD) 83 and scans in the horizontal direction. The first AOD 83 is made of, for example, GaP, LiNbO3, PbMoO4.

This diffraction angle is determined by the frequency of the high-frequency signal for driving the first AOD 83. Therefore, a first voltage controlled oscillator (abbreviated as VCO) is used as a signal source for driving the AOD 83.
84, the driving power supply voltage of the first VCO 84 corresponds to the frequency of the high-frequency signal.
AOD 83 also corresponds to the deflection angle of the beam. The driving power supply voltage of the first VCO 84 is
Is converted into a digital signal and input to the beam spot position detection circuit 54.

The beam diffracted by the first AOD 83 is converted into parallel light through a lens 89, and then is incident on a second AOD 86 that performs vertical scanning. This second AO
D86 is driven by a second VCO 87 serving as a drive signal source. The drive power supply voltage of the second VCO 87 is A / D
The signal is converted into a digital signal by a converter 88 and is input to a height information calculation circuit (equivalent to the distance calculation circuit 56 in FIG. 1) 92, so that information on the vertical deflection angle can be obtained by the drive power supply voltage. ing.

The beam diffracted by the second AOD 86 is converted into parallel light through the lens 90 and is incident on the light incident end face of the image guide 31 for transmitting measurement light.

In the present embodiment, the lenses 89 and 90 are
As a −θ lens system, the deflection angle of the beam is set so as to linearly correspond to the position information of the image plane, and the VCO 8
The irradiation position of the spot light on the incident end face of the measurement light transmission image guide 31 can be determined by the value of the DC voltage for driving the light guides 4, 87.

Here, the first and second AODs 83 and 86
And second VCO 8 serving as high-frequency signal sources for
The modulation waveforms of the drive power supply voltages (also referred to as VCO voltages) 4 and 87 are stepped sawtooth waveforms as shown in FIGS. 10A and 10B, and the periods thereof are T1 and T1 in the horizontal and vertical directions, respectively. When T2 is set, T2 is set to n times T1 so that a scan beam having n horizontal scanning lines can be obtained.

The light that has propagated through the measuring light transmission image guide 31 and illuminated on the surface of the subject 50 through the measuring light projecting lens 45 is reflected and propagates through the shape measuring image guide 32 through the shape measuring objective lens 46 to form an image. The light is projected on the tape-like optical fiber bundle array 48 via the lens 47.

One tape-shaped fiber bundle 48 (i) is 1
One photoelectric conversion element 49 corresponding to the pixels in the column is collected and condensed.
It is led to (i).

In the present embodiment, the optical system shown in FIG. 11 is used as the measuring light projecting lens 45 in order to irradiate the measuring beam to the edge direction of the viewing angle in the optical system of the endoscope 2. .

As shown in FIG. 11, light emitted from the fiber 31a of the image guide 31 for measuring light transmission is
The beam is converged at 4, and once stopped by the stop 95 at the focal position, and further expanded by the concave lens 96, so that the beam irradiation direction is widened. Note that the lens 94 is an f-θ lens.

Therefore, in order to obtain the direction of irradiation of the beam on the object plane (or the object plane), calculation is performed from the reverse focal length and arrangement of the lens 96. If the configuration data of such an optical system is known, the VCO voltage for driving the first and second VCOs 84 and 87 is A / D converted, and the position and irradiation direction of the measurement laser beam are determined based on the data. Obtainable.

Alternatively, the first and second VCOs 84, 8
The driving power supply 7 may be configured to perform D / A conversion of digital data and to calculate the irradiation direction based on the digital data. Either method does not require an encoder for obtaining the beam irradiation position in the beam scanning means, so that the three-dimensional measurement endoscope device 80 is realized with a simple configuration.

In this embodiment, the photoelectric conversion element 4
9 (i), the signal of each photoelectric conversion element 49 (i) is amplified by the amplifier 51 (i) having the same characteristic, and the signal is amplified by the multi-channel comparator 97. The position in the vertical direction is obtained from the position of the photoelectric conversion element 49 (i) having the highest level in comparison.

The laser spot position detection circuit 54 detects the position of the laser spot from this data and the horizontal position data calculated by referring to the output value of the first VCO 84.

A height information calculation circuit (corresponding to the distance calculation circuit 56 in FIG. 1) 98 is provided at the next stage of the laser spot position detection circuit 54. Then, the height information is calculated according to the above equation. The second corresponding to the irradiation position in the vertical direction
The information on the height of each laser spot position is calculated from the output of the A / D converter 88 and the position of the obtained laser spot.

Then, each laser spot position and its height information are recorded in the frame memory 99 in correspondence with each other, and the video signal synthesizing circuit 59 uses the height information corresponding to each laser spot position to produce a three-dimensional image. The video signal is converted into a video signal corresponding to the display and displayed on the display 5.

For example, a PLL circuit of a synthesizer type as shown in FIG. 12 may be used as the second VCO 87 for performing vertical scanning with a long period. This PLL circuit has a frequency f of a crystal reference oscillator 122 using a crystal 121.
The oscillation output of i is input to the phase comparator 123.

The comparison output of the phase comparator 123 passes through a low-pass filter 124, and the VCO 125
Is subjected to voltage-controlled oscillation, and its output is obtained from the output terminal. The output is also divided by the division ratio M by the programmable divider 126, and the output is input to the phase comparator 123. Then, by comparing the divided signal, the VCO 12
5, an output signal having a frequency of fi · M is obtained.

The frequency division ratio M can be set by the data of the data input section 127. Then, the data of the data input section 127 is sequentially varied, and the frequency division ratio M is changed, thereby causing the VCO to operate as if a VCO voltage as shown in FIG. Since negative feedback control is performed using the low-pass filter 124, it is better to directly drive the VCO with a sawtooth wave for horizontal scanning for high-speed scanning.

This embodiment has the following effects. First
In the method of scanning a beam using a polygon mirror and a galvano scan mirror as in the embodiment, an encoder must be used for each axis. On the other hand, if an acousto-optic deflector is used, for example, a VC
When O is used, the DC signal corresponding to the position information can be obtained directly from the voltage of the driving power supply, so that the configuration is simplified.

The other effects are the same as those of the first embodiment.

In the above-described three-dimensional shape measuring apparatus, the point of the light applied to the object surface on the original image plane corresponding to the spot position is known, and the image pickup system uses a single image pickup element for each vertical line. Since the image is taken, it has a resolution only in the horizontal direction. In other words, the light source and the imaging system in a method usually called the “light-section method” are opposite ideas.

However, since the optical system of the endoscope is extremely wide-angle, it is necessary to consider the distortion as compared with the ordinary light section method.

Therefore, the position of the emission point, the distance to the subject, and the incident position (only in the horizontal direction) in the imaging system are set as R
A method of using a Lookup Table for recording the data in an OM or the like and collating the measured data with the data is used.

On the other hand, if the three-dimensional position is detected in accordance with equations (Equations 15 to 17 described later) in which distortion is taken into account, highly accurate three-dimensional position detection is possible. In Equations 7 to 9 described above, the third value of the object in the optical system having no distortion is obtained.
The dimension measurement (FIG. 13) is formalized,
This is because the error is small when the object B is distant and the projected light beam is nearly parallel to the optical axis (ez).

Here, the projection optical system and the imaging optical system are assumed to be telecentric optical systems and have the same focal length f. In an actual endoscope optical system, chromatic aberration correction and astigmatism correction are performed, and a group lens is always used because a wide-angle concave lens is used at the exit end. Here, a virtual lens equivalent to this is considered.

The coordinate reference point is set to the focal point O of the exit lens.
(0,0,0). In FIG. 14, light emitted from the fiber exit surface goes straight and hits a virtual lens surface z = −f.
Thereafter, a spot is formed on the subject as a projection image P.

The optical system having the distortion aberration is a virtual lens which reversely traces the light beam from the spot with the angle θ between the optical axis (ez) and the straight line connecting the projected image on the object and the focal point of the spot emitted from the fiber. The height of the image at the plane is approximately fsi
Since it is nθ, it is ftan θ in an image having no aberration, and is multiplied by cos θ (see FIG. 14). Since this is a spot image at the virtual lens surface z = f of the fiber, sin θ = √ (Xi · Xi + Yj · Yj) / f, cos
θ = √ (f · f−Xi · Xi−Yj · Yj) / f. Here, √ (f) means the square root of f in ().

FIG. 15 shows an actual telecentric optical system in which a grid-like pattern is projected perpendicularly onto a flat object plane. As shown in FIG.
FIG. 16 shows a conceptual diagram of the three-dimensional shape measurement. Based on this, a formulation is shown below. Focus O of the projection optical system
A straight line connecting (0,0,0) and the projected image of the spot and z = f
Assuming that the intersection of the surfaces is Q ', the coordinates are Q' = {Xif // (fff-Xi-Xi-Yj-Yj
), Yj f / √ (f ・ f-Xi ・ Xi-Yj ・ Yj
), −f｝. Therefore, the equation of a straight line connecting Q 'and O is OQ': x√ (f ・ f-Xi ・ Xi-Yj ・ Yj) / Xi = y√ (f ・ f-Xi ・ Xi-Yj ・ Yj) / Yj = −z (Equation 10) On the measurement side, the focus M and the image on the measurement-side lens surface are treated in the same way, and the angle of the straight line connecting the ez axis and the spot image to M is φ, and the imaging point R = (Rx, Ry, Mz− f), sinφ = √ (rx · rx + ry · ry) / f, cos
φ = √ (f · f−rx · rx−ry · ry) / f, where rx = Rx−Mx, ry = Ry−My A straight line connecting the projected image of the spot and the focal point M on the measurement side and the lens surface on the imaging side Let the intersection of z = Mz-f be R ', R' = M + {rx f /} (ff-rx-rx-ry.
ry), ry f / √ (f · f−rx · rx−ry · ry
), −f｝ The equation of a straight line connecting M and R ′ is MR ′: (x−Mx) √ (f · f−rx · rx−ry · ry) / rx = (y−My) √ (f · f−rx · rx−ry · ry) / ry = Mz−z (Equation 11) The spot P (Xp, Yp, Zp) is a common solution of the equations (10) and (11). However, since the image sensor on the imaging side of the present invention does not have a resolution in the Y direction, ry is indefinite, and therefore, Must be represented by a family of straight lines with ry removed from. The family of curves is, for example, FIG.
7 is included in the curved surface. Assuming that the lens arrangement is on the same z = f plane, the constraint condition of My = 0 is added since Mz = 0 or the way of taking the coordinate axis is arbitrary, and the equation 1
The expression of the first term = the third term is expressed by using ry = (y / x−Mx) rx using the first term and the second term of (1). (X−Mx) √ (f · f−rx · rx− (y / (x−Mx) · (y / (x−Mx) rx · rx / rx (Equation 12) The common solution of Equations 10 and 11 is P (Px, Py,
Pz). From equation (10), Pz = −Px√ (f · f−Xi · Xi−Yj · Yj)
/ Xi, Py = Yj Px / Xi is substituted into Equation 12 to obtain (Px−Mx) √ (f · f−rx · rx− (YjPx /
Xi). (YjPx / Xi) rx.rx / ｛(Px-M
x) ・ (Px-Mx)｝) rx = Px√ (f ・ f-Xi
Xi-Yj Yj). By expanding this, (Px−Mx) (Px−Mx) (f · f−rx · rx) − (YjPx / Xi) · (YjPx / Xi) · rx · rx = Px · Px (f · f-Xi.Xi-Yj.Yj) rx.rx / (Xi.Xi) (Equation 13) When the expression 12 is converted to a polynomial form with respect to Px, f.f ｛1- (rx.rx / Xi.Xi) ｝ Px Px −
2 (f · f−rx · rx) Mx Px + (f · f−rx ·
rx.Mx.Mx) and the solution is Px = (f.fx-rx.rx) .Mx. +-. (Mx.Mx (f.f-rx.rx) (f.f-rx.rx)-(f -F-rx-rx) -f-f-Mx-Mx (1-rx-rx / (Xi-Xi)) / {f-f (1-rx-rx) / αi-Xi) = Mx Xi (f-fx-rx) ± rx Xi {(f-rx-rx) (rx-rx / Xi-Xi) / f (Xi-Xi-rx-rx)} (Equation 15) Becomes The coordinates of Py and Pz can be easily obtained from Expression 9.

Py = Yj · Px / Xi (Equation 16) Pz = Px√ (f · f−Xi · Xi−Yj · Yj) / Xi (Equation 17) In the following, the validity of the sign of Expression 15 is actually a numerical value. Will be considered. In the following example, the projection side focus is set to O
(0, 0, 0) and the measurement-side focal point M (5, 0, 0). The length is set in mm in consideration of the actual endoscope. Using the example of FIG. 18A, Q1 and rx = 0 and f =
If 3 is used (Equation 414), the content of root becomes zero, so that Px = Mx = 5 regardless of the sign. The example in FIG. 18B includes the midpoint of the straight line OM of the spot and is included in a plane perpendicular to the OM, so that Xj = −
Since r x is obtained, the quadratic term of Px disappears in Expression 13, and Px = Mx / 2. In the example of FIG. 19A, the spot is between the planes x = 0 and x = 5 including the optical axes of both lenses. Xj, rx
Substituting into Equation 14, Px = 13.4 and 3.07 respectively with positive and negative signs. On the other hand, as shown in FIG.
If x = 5, Px = 10, 3.33. That is, the sign of equation (14) takes a positive sign when the spot is between the optical axes of both lenses and Xi · rx> 0. If one of them is 0, the equation (14)
The content of t becomes 0 and does not depend on the sign.

In conclusion, even in an optical system in which distortion is taken into account, the formulation of three-dimensional shape measurement by light cutting can be obtained by equations 15 to 17, which are unexpectedly easy.
The method using such an approximate expression is based on the aforementioned Lookup T
Compared to the system using the able method, there is an advantage that a complicated operation such as calibration is not required for each endoscope.

[0113]

As described above, according to the present invention, a scanning spot light projecting means for scanning a spot light and projecting the spot light onto an object, an image forming means for forming an image of the spot light reflected by the object, and Light position detecting means for detecting the position of the spot light with respect to the two-dimensional measurement area by a light receiving element arranged one-dimensionally at the image forming position of the subject by the image forming means; and the output of the light position detecting means and the spot light Position calculating means for calculating the position of the spot light on the subject from the scanning position and the positions of the scanning spot light projecting means and the light position detecting means,
Is provided, so that even with a simple configuration, and even when the object to be measured is moving, if the scanning spot light is performed at a high speed, by using the outputs of the one-dimensionally arranged photoelectric conversion elements, Three-dimensional measurement can be performed with high accuracy in a short time.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a three-dimensional measurement endoscope apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of the principle of distance measurement.

FIG. 3 is a diagram showing a tape-shaped fiber bundle provided with a diffusion plate at an incident end in a modification of the first embodiment.

FIG. 4 is a perspective view showing a modification of FIG. 3;

FIG. 5 is a perspective view showing a structure of a light position detecting means according to a second embodiment of the present invention.

FIG. 6 is an enlarged view showing a thin glass plate with a reflection coat in FIG. 5;

FIG. 7 is a perspective view showing the structure of a light position detecting means according to a third embodiment of the present invention.

FIG. 8 is an overall configuration diagram of a three-dimensional measurement endoscope apparatus according to a fourth embodiment of the present invention.

FIG. 9 is an overall configuration diagram of a three-dimensional measurement endoscope apparatus according to a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a specific waveform example of a VCO voltage.

FIG. 11 is a diagram showing a specific example of a measurement light projecting lens.

FIG. 12 is a block diagram showing a modified example of a VCO that performs vertical scanning.

FIG. 13 is an explanatory diagram of three-dimensional measurement in an optical system having no distortion.

FIG. 14 is a diagram showing a relationship when projection is performed by an optical system having distortion and an optical system having no distortion.

FIG. 15 is a diagram illustrating distortion when a lattice-like pattern is projected onto a plane by a telecentric optical system.

FIG. 16 is an explanatory diagram of three-dimensional measurement in an optical system having distortion.

FIG. 17 is a diagram showing an example of a family of distortion aberration curves.

FIG. 18 is a diagram showing a comparison of specific numerical examples of spot position measurement between an optical system having distortion and an optical system having no distortion.

FIG. 19 is a diagram showing a specific numerical example of position measurement for a spot position different from that in FIG. 17;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... 3D measurement endoscope apparatus 2 ... Endoscope 3 ... Light source unit 4 ... 3D measurement unit 5 ... Display 6 ... Insertion part 7 ... Operation part 8 ... Eyepiece part 9 ... Universal cable 14 ... Lamp 16 ... Lighting Light guide for light transmission 18 ... Illumination lens for observation 19 ... Objective lens for observation 21 ... Image guide for observation 30 ... Laser beam scanning means 31 ... Image guide for measurement light transmission 32 ... Image guide for shape measurement 34 ... Laser 35 ... Polygon Drive motor 36 ... Polygon mirror 38 ... Galvanometer mirror 39 ... Lens 45 ... Measurement light projecting lens 46 ... Shape measuring objective lens 47 ... Imaging lens 48 ... Tape fiber bundle array 48 (1) to 48 (n) ... Tape Fiber bundles 49 (1) to 49 (n) ... photoelectric conversion elements 52 ... changeover switches 54 ... laser spot position detection times 56 ... distance calculating circuit 58 ... three-dimensional shape memory 59 ... video signal combining circuit

Continued on the front page (72) Inventor Hideyuki Shoji 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Industrial Co., Ltd. (72) Inventor Yoshitaka Miyoshi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Within Kogyo Co., Ltd. (72) Inventor Akira Kusumoto 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Kogyo Co., Ltd. (72) Inventor Akira Murata 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Industrial Co., Ltd.

Claims (1)

[Claims] 1. A scanning spot light projecting means for scanning a spot light and projecting the spot light on an object, an image forming means for forming an image of the spot light reflected by the object, and an image forming position of the object by the image forming means. Light position detecting means for detecting the position of the spot light with respect to the two-dimensional measurement area by means of one-dimensionally arranged photoelectric conversion elements; output of the light position detecting means, scanning position of the spot light and scanning spot light projecting means; A position calculating unit configured to calculate a position of the spot light on the subject from the position of the light position detecting unit.