JPH03248004A - Configuration measuring apparatus - Google Patents

Abstract

PURPOSE:To simplify the constitution of an image sensing element by specifying the space coordinates of the surface of a body to be measured based on the identified data of slit light and the position data of received light, and converting a part of digital processing into analog processing. CONSTITUTION:The laser light from a laser light source 1 forms the slit light through a lens system 2. The light is projected on the surface of the a body to be measured 4 through a polygon mirror 3. When the slit light crosses a photosensor 5, a reset signal 6 is outputted. A sawtooth wave generator 7 is reset with this signal. The identified data of the slit light n(t) are outputted as the crest values of the sawtooth waves. The reflected light from the surface of the body 4 is received with an image sensing device 9. The slit-shaped optical image of the surface of the body 4 corresponding to the slit light n(t) is formed on a photosensor group 11 forming a non-scanning type image sensor element 10. Therefore, the scanning control for the sensor group 11 for every time is not required in detecting the position data of the optical image on the surface of the body 4. The position data and the identified data which are transferred from a CCD array 12 are matched in a matching-operation processing part 13. Thereafter, the data are converted into the space coordinates of the surface of the body.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a shape measuring device, in particular, to irradiate a light beam onto the surface of an object to be measured, and deflect and scan the light beam to obtain an optical image of the surface of the object to be measured. This invention relates to an improvement of a non-contact shape measuring device that measures the shape of an object.

[Prior art] Three-dimensional object shape meter using optical system 71! IJ is C
Applications are expected in various fields such as AD/CAM, computer vision, robot eyes, measurement and analysis of biological and natural objects in fields such as medicine and fashion, and graphic design.

Shape measurement using conventional optical methods can be divided into several methods, and the stereo method is known as a representative method. According to this stereo method, images of an object to be measured are first captured from a plurality of viewing directions using a plurality of industrial cameras, and the shape of the object to be measured is extracted from the images.

This method is based on the principle of binocular stereopsis, and the captured image data is captured as grayscale signal data over the entire imaging surface, and in order to extract only the necessary shape from this information, , corresponding point detection processing is unavoidable, and this requires various image processing, huge storage capacity, and long processing time, so it has not yet been realized as a high-speed and simple device. in a state.

Among other conventional methods, the optical cutting method is considered to be the most common and highly practical. In this optical cutting method, a spot-shaped or slit-shaped light beam is irradiated onto the object to be measured, and a video signal based on an optical image of the surface of the object to be measured corresponding to the light beam is input into a computer using an imaging device. ,
The spatial coordinates of the surface of the object to be measured are determined from the positional information of the optical image on the imaging surface obtained as a result of processing this information and the relative positional relationship between the light beam and the imaging device.

That is, according to the conventional optical cutting method, for example, a deflected and scanned light beam is irradiated onto the surface of an object to be measured, and an optical image of the surface of the object to be measured by this light beam is converted into a video signal using an ITV camera. to import it into the computer.

Therefore, according to this conventional method, the position of the optical image on the surface of the object to be measured is specified by sequentially electrically scanning the entire imaging surface, and this is performed for each light beam being deflected and scanned. The shape of the three-dimensional object is measured from a large amount of data obtained in this way.

However, according to the conventional light sectioning method, as mentioned above, in order to detect and specify each point on the surface of the object to be measured, it is necessary to scan the entire imaging plane each time, and as a result, shape measurement The problem was that it took an extremely long time and real-time measurement was impossible. Normally, the time required to scan one screen is about 1/60 to 1/30 seconds in the case of a normal industrial television camera, for example, and in such a slow measurement operation, the shape of the object to be measured cannot be measured in real time. It has been almost impossible to perform measurements on moving objects.

In particular, in order to measure the shape of a three-dimensional object with practically sufficient resolution, the number of measurement points must be large. The beam deflection scanning itself had to be extremely slow, making it impossible to measure with sufficient resolution in real time.

In order to solve the above problems, in the past, Japanese Unexamined Patent Publication No. 62
The shape i''ln1ln1 method shown in No. 228106 has been proposed, and according to this conventional device, the deflection angle of the slit light irradiated onto the object to be measured is used as the slit light identification information, and this is used as the position information of the received light. A matching calculation is performed, thereby providing an improved shape meter a11 that does not require high-speed readout control.

[Problems to be Solved by the Invention] However, according to the conventional device described above, the structure of the image sensor becomes extremely complicated in order to simultaneously process light receiving position information and slit light identification information, and in particular, it is difficult to store image information. There is a problem in that the structure of the image sensor becomes complicated due to the storage capacity of the memory holding section and the data bus, and the device itself becomes large, making it difficult to mount it on an actual robot or the like.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to improve the conventional device described above and use an image sensor in which a part of the digital processing performed in the conventional device is replaced with analog processing. An object of the present invention is to provide a measuring device with a simple configuration.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a deflection irradiation device that deflects and scans a slit light toward the surface of an object to be measured under predetermined scanning control, and the deflection irradiation device. a sawtooth wave generator that outputs a sawtooth wave synchronized with the deflection period of the slit light deflected by the slit light as slit light identification information, and a one-dimensional or A group of photosensors arranged in a two-dimensional manner are provided corresponding to the group of photosensors, and the output of the photosensor on which an optical image is formed is used as a trigger, and the peak value of the sawtooth wave at this time is used as slit light identification information. Transfer C
The apparatus is characterized in that it includes a CD array, and an arithmetic processing unit that calculates the shape of the object to be measured by comparing and calculating the position information of the photosensor and the slit light identification information transferred by the CCD array.

[Function] As described above, in the present invention, the slit light is irradiated onto the surface of the object to be measured while being deflected and scanned, the object surface is stroked by the slit light, and the object surface is moved on the imaging plane correspondingly. The position information on the imaging plane of the optical image of the surface of the object to be measured is
It detects the light received by a large number of mutually independent photosensors that make up the imaging surface. On the other hand, the deflection angle of the slit light is output as a sawtooth waveform synchronized with the deflection period of the slit light, and the analog peak value of this sawtooth waveform is obtained as slit light identification information. The spatial coordinates of the surface of the object to be measured are specified from the light receiving position information. As a result, it is possible to construct a measuring device that can sufficiently track the object to be measured even when the slit light is scanned at high speed.According to the present invention, the surface shape of a three-dimensional object can be measured at high speed. becomes possible.

[Example] Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an example of a basic system configuration for measuring the surface shape of an object to be measured 4 using a light beam consisting of slit light.

A laser beam from a laser light source 1 is vertically expanded by a lens system 2 including a cylindrical lens to form a slit beam, and a polygon mirror 3. The surface of the object to be measured 4 is irradiated with the light. The slit light is deflected by sequentially changing its irradiation angle over time as shown in the figure by rotating the polygon mirror 3, and can stroke the surface of the object to be measured 4. The deflection angle of the slit light is uniquely determined by the rotation angle of the polygon mirror. Therefore, when identifying the slit light, the rotation angle of the polygon mirror may be directly determined by Δ-1, but the polygon mirror is usually controlled as a rotational motion with a constant angular velocity, and therefore the slit light also has a constant angular velocity ω. Since deflection scanning is performed, identification of the slit light can be realized by measuring the elapsed time t from the reset signal 6 output when the light passes a certain reference position. Since the identification information of the slit light beam deflected in this manner depends on the time t, the time t can be used as the identification information of the slit light for subsequent calculations. 1st
In the figure, the slit light is shown as n (t).

A feature of the present invention is that the identification information of the slit light is provided as an analog signal, and for this reason, the elapsed time t described above can be obtained from the peak value of the sawtooth wave reset by the reset signal 6. It will be done.

In the example shown in FIG. 1, a photosensor 5, such as a phototransistor, is provided for detecting the reference position, and when the slit light crosses this photosensor 5, a reset signal 6 is output, and this signal generates a sawtooth waveform. The generator 7 can be reset and the identification information of the slit light n (t) can be output as the peak value of the sawtooth wave.

Therefore, according to the present invention, the deflection angle of the slit light n (t) that strokes the surface of the object to be measured 4 is specified by the peak value of the sawtooth wave, and the analog identification information . be understood.

On the other hand, in this embodiment, the reflected light reflected from the surface of the object 4 is received by the imaging device 9, and the slit light n (
A slit-shaped optical image of the surface of the object to be measured 4 corresponding to time t) is formed on the photosensor group 11 forming the image sensor 10 of the imaging device 9 .

In the embodiment, the image sensor 10 is formed of a non-scanning type image sensor such as a video synchronization type image sensor, and the photosensor group 11 is a one-dimensional or two-dimensional array of mutually independent photosensors arranged in a line. It is configured as an array. Therefore, the video information of the photosensor group 11 can be detected independently for each pixel, making parallel processing possible. Therefore, the photosensor group 11
When the slit-shaped optical image moves above, position information of the entire slit-shaped optical image is based on the optical image reception of each photosensor constituting the photosensor group 11;
That is, the addresses of all pixels corresponding to the slit-shaped optical image can be detected.

Therefore, in detecting the position information of the optical image on the surface of the object 4, there is an advantage that the detection can be performed in a short time without requiring scanning control of the photosensor group 11 each time as in the conventional method.

On the other hand, as described above, the sawtooth wave generator 7 outputs the identification information of the slit light as the peak value V of the sawtooth wave.
As a result, the peak value V at the time of light reception by the photosensor group 11
By storing the information in association with the slit light, the position information and the slit light identification information can be obtained at the same time. In this embodiment, both pieces of information are read out by the transfer action of the CCD array 12.

The device information and identification information constituted by the CCD array 12 are then subjected to a matching operation in a matching calculation processing section 13, and then converted into spatial coordinates of the surface of the object to be measured.

That is, according to the present invention, both the analog identification information V of the slit light n(1) and the corresponding position information of the slit-shaped optical image can be detected in real time and in association with each other, and the object can be determined from both information. It becomes possible to measure the surface shape of No. 4 at high speed.

In FIG. 1, polarized irradiation devices 1.2. 3. If the relative positions of the image pickup device 9 and the image pickup element 10 are fixed and the positional relationship is known in advance, the object 4 itself remains stationary during the measurement period by performing deflection scanning according to the present invention at high speed. By performing this measurement at a speed sufficiently higher than the movement of the object 4 itself, even the moving object 4 is considered to be in a stationary state during the measurement period, and its shape is It is possible to measure

FIG. 2.3 shows that in the embodiment shown in FIG. 1, the surface shape of the object 4 can be specified from the identification information of the slit light and the position information of the optical image. That is, FIGS. 2 and 3 are based on the mirror reflection center M shown in FIG.
Slit light n(t) reflected from (xm, ym, z+n), a point P (X) on the surface of the object to be measured 4 irradiated by it.

Y, Z) and its optical image! The geometric optical relationship between (x, O, zi) is projected onto the xy plane (FIG. 2) and the X2 plane (FIG. 3).

In the second and third cases, the solid line shows the state in which a single slit beam is scanned on the object to be measured using a single deflection irradiation device, and the chain line shows the situation in which the second deflection irradiation device is further placed at a different position. By using two deflection irradiation devices in this way, even if the object to be measured has irregularities, scanning with one slit light will scan the object with a shadow. It becomes possible to largely eliminate unmeasurable surfaces.

In FIGS. 2 and 3, the origin of the orthogonal coordinate system (x, y, z) is, for example, the center O of the photosensor group 11, the X axis is horizontal and is set parallel to the photosensor group 11, and the y The axis is set to coincide with the lens optical axis of the imaging device 9,
Furthermore, the Z axis is set in the vertical direction.

Therefore, the coordinate value (X) of point P on the surface of object 4.

As shown in the figure, Y, Z) are specified by the slit light n(t) and the reflected light R(t), and can be set as the measurement conditions by the lens position, the coordinate value of the mirror position M, and the rotational angular velocity ω of the slit light. , is obtained as follows using the identification information of the slit light n (t) obtained as a measurement result and the coordinate values (xi, 0.zi) of the optical image I of the point P.

In addition, in the measurement principle of the present invention shown in Figure 2.3 below,
The identification information will be explained as the elapsed time t from the reset signal 6. Of course, in the present invention, it is clear that this identification information t is processed as an output peak value V of the sawtooth wave generator 7 in order to be processed as an analog signal.

0: Center of photo sensor group (orthogonal coordinate system origin) 0 (0,
0, O) L: Lens center L of the imaging device 9 (0,!/J!, 0) M, M-: Mirror reflection center M (xw, ym, zw).

M-(xe-, +zw-) ym P, P-: Point on the surface of the object to be measured P (X, Y, Z).

P(X, YZ) 1.1-: Optical image 1 of point 21 point P' (xi, yl, zi) 1 = (xl -, yi -, zi -) P, D,
: Reference position of light beam (counter reset timing position) 0'0-" Angle α between the reference position of the slit light and the X-axis, α' Angle ω between the Nislit light and the reference position of the slit light, ω' The angle between the Nislit light and the X-axis Rotational angular velocity 1.1 - Elapsed time after passing the Nislit light reference position Subscript x
y, subscript xz: As above, M, M-, P, PI and ■゛ Straight line I representing the projection point on each point xy plane, xz plane Therefore, - tan (α+α0) (X-xlm)+yl (2) Straight line IxzLxzPxz: Therefore, I (1) (2) From
(10αo) In equations (2) and (4) above, α is the product of the rotational angular velocity ω of the slit light and the identification information t, that is, α−ω・
t, and as a result, equations (2) and (4) become Y-tan
(ωt+cro) (X-xm)+7m(5) 1 Therefore, according to the above equations (3), (5), and (6), the object 4
The three-dimensional coordinate values of point P on the surface of (x, y.

2) is the identification information of the slit light n (t), that is, the elapsed time t from the predetermined reset timing, and the position information (xi, 0.
It is understood that it is determined by both z).

FIG. 4 shows a preferred embodiment of a non-scanning image pickup device that simultaneously latches and stores identification information V of the optical slit light n (t) and position information of an optical image on the photosensor group 11 of the image pickup device 10. It is shown.

This non-scanning type image sensor basically consists of a photosensor group 11 and a CCD array 12 shown in FIG.

In FIG. 4, the photosensor group includes a plurality of (MXN) phototransistors 1 arranged in a row and independent of each other.
It is composed of 5.

Therefore, as is clear from the above description, the reflected light from the surface of the object 4 is received by the imaging device 9, and an optical image of the surface of the object 4 is formed on one of the phototransistors 15 of the photosensor group 11. That will happen.

The photoresponse output of this phototransistor 15 is
12 CCD arrays are sent.

In FIG. 4, a CCD array 12 is provided corresponding to the photosensor group 11, and includes M CCD arrays 12 arranged horizontally in the figure, and each array is divided into N element CCDs. has been done.

In the embodiment, since the image sensor 10 has a two-dimensional (MXN) light receiving surface, each of the CCDs arranged in the horizontal direction
Each piece of information in array 12 is sequentially vertically converted and read out by a CCD array 20 whose output is vertically arranged.

The output of one of the photosensors 15 that receives light is used as a trigger signal for the sample and hold circuit 22 in the present invention. The other signal input of the sample and hold circuit 22 receives the sawtooth wave output V from the sawtooth wave generator 7.
As a result, when any of the photosensors 15 receives light, the peak value V of the sawtooth wave at that time is stored in the sample and hold circuit 22. Then, when the CCD array 12 transfers this stored peak value ■,
It is understood that the transfer order indicates position information, and the transfer peak value indicates identification information.

As described above, according to the present invention, since the analog peak value V is used as the slit light identification information, it is possible to input the signal using only one signal, compared to the conventional case where the signal is processed as a digital signal. It is possible to make the image sensor 10 small and lightweight, and to obtain an image sensor that is highly practical as a visual device for a robot or the like.

FIG. 5 shows the memory action of the CCD sensor 12 based on the position information, that is, the light reception output of one of the photosensors 15 and the analog slit light identification information, and the sawtooth wave is synchronously controlled by the reset signal 6. , a peak value V proportional to the elapsed time t after the output of the reset signal 6 is supplied to each sample and hold circuit 22.

According to any of the photosensors 15, FIG. 5, when the j-th photosensor receives light, the received light output is 100;
The sample and hold circuit 22 samples and holds the peak value V of the sawtooth wave, which is proportional to the time of light reception with the reset signal 6 as the reference point.

The voltage stored in the sample and hold circuit 22 is
It is shown at 200 in the figure. When the deflection scanning of the slit light is completed, the voltage held in the sample and hold circuit (200 in FIG. 5) is transferred to the CCD array 12 and sequentially transferred to the outside.

The peak value V of each sawtooth wave can be transferred and controlled as identification information to (12).

Therefore, a desired shape nl can be determined by comparing the position information determined by the photosensor 15 and the identification information consisting of the peak value V, and this matching calculation is performed by the calculation processing section 13 shown in FIG. It is being done.

As described above, it is understood that the photosensor that receives the slit light in one deflection scan stores the peak value at that time as the voltage value of the sample and hold circuit 22.
Next, reading out such stored information will be explained.

In FIG. 4, φX indicates the readout drive pulse in the horizontal direction (1 to N) of each CCD array 12, while the vertical CC
φy is supplied as a read drive pulse for the D array 20.

FIG. 6 shows the waveforms of both drive pulses φX and φy, and as shown in the figure, it is understood that the vertical drive is performed at a higher speed than the horizontal drive.

Therefore, according to this embodiment, M signals of N digits are read out, and then M signals of (N-1) digits are sequentially read out.

Further, in the embodiment, the output of the vertical CCD array 20 is supplied to the above-mentioned matching calculation processing section 13 of FIG. 1 through the amplifier 23, and at this time, according to the embodiment,
The output of the amplifier 23 is AD converted and supplied to the arithmetic processing section 13. Therefore, according to this embodiment, the arithmetic processing section 13
The order of the data supplied to indicates the position information of the photosensor that received the light, and the peak value V at that time indicates the identification information of the slit light.

Therefore, the matching calculation processing section 13 can perform desired shape measurement calculations using the principle shown in FIG. 2.3 described above.

[Effects of the Invention] As explained above, according to the present invention, the surface of the object to be measured is stroked by the slit light, and a photo of the optical image of the surface of the object to be measured moves on the photosensor group accordingly. Position information on the sensor group can be detected in real time based on the light reception of each photosensor. On the other hand, the identification information of the slit light is obtained from the peak value of the sawtooth wave obtained in synchronization with the deflection period of the slit light, and the shape of the object surface can be measured at high speed from the position information and identification information. By scanning the surface of an object with slit light, it is possible to measure the shape of a moving object very well.

[Brief Description of the Drawings] Fig. 1 is an explanatory diagram of a measuring device showing a preferred embodiment of the object surface measurement method according to the present invention, and Fig. 2.3 shows the principle of the object surface measurement method according to Fig. 1. 4 is an explanatory diagram showing a specific example of the image sensor suitable for FIG. 1, FIG. 5 is an explanatory diagram showing the identification information capture function of the image sensor shown in FIG. 4, and FIG. 6 is a CCD. FIG. 3 is an explanatory diagram showing the data read operation of the array. 1... Laser source 0 1 2 3... Polygon mirror... Object to be measured... Sawtooth wave generator... Imaging device... Imaging element... Photo sensor... CCD array calculation processing section

Claims (1)

[Claims] (1) A deflection irradiation device that deflects and scans a slit light toward the surface of an object to be measured under predetermined scanning control, and a sawtooth wave that is synchronized with the deflection period of the slit light deflected by the deflection irradiation device. a sawtooth wave generator that outputs identification information; a group of photosensors arranged in one or two dimensions that forms an optical image of the surface of the object to be measured using the slit light; and a group of photosensors that correspond to the group of photosensors. A CCD which is provided as a slit light identification information and transmits the peak value of the sawtooth wave at this time as a slit light identification information using the photo sensor output on which an optical image is formed as a trigger.
A shape measuring device comprising: an array; and a calculation processing unit that calculates the shape of the object by matching the position information of the photosensor transferred by the CCD array with the slit light identification information.