JPH02223809A - Three-dimensional shape measuring instrument using light cutting method - Google Patents

Abstract

PURPOSE:To obtain a device which has high accuracy at low cost by picking up light cutting lines by two light cutting line image pickup means in different directions and recognizing the three-dimensional shape of a body to be measured from the mean value when the difference between the light cutting images is small or respective cutting lines when the difference is large. CONSTITUTION:The image pickup cameras 2a and 2b are controlled with a synchronizing signal and the light cutting images 5a and 5b are inputted alternately. Those input images are switched at intervals of, for example, 1/30 second. Then the light cutting images 5a and 5b are converted by a comparator into binary data 51a and 51b so at the process fast, which are processed to calculate the three-dimensional coordinates of a position on the surface of the body 3 to be measured, thereby obtaining recognition results 52a and 52b of the three-dimensional coordinates. Consequently, the three-dimensional shape measuring instrument of relatively simple constitution is realized at low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement of a three-dimensional shape measuring device using a light cutting method.

<Prior Art> FIG. 5 shows an outline of a three-dimensional shape measuring device using the optical cutting method. When the slit light 12 is irradiated from the light source 11, a light cut m14 is obtained on the surface of the object to be measured 13, and this is imaged by an imaging device 15 such as a CCD camera. Then, by processing the data of the optically sectioned image obtained by the imaging/imaging device 15 using the triangulation method, the position on the three-dimensional coordinates of each point on the surface of the object to be measured 13 is determined, and the data of the three-dimensional shape is obtained. This is what we get.

<Problems to be Solved by the Invention> In measurement using such a light cutting method, as the angle θ between the light source 11 and the imaging device 15 approaches 90', it becomes easier to detect irregularities on the surface of the object to be measured 13. Improves accuracy. However, if the object to be measured 13 has large irregularities, it is recommended to increase the angle ξ because if the angle θ becomes large, blind spots will occur and there will be many missing points where data cannot be obtained. There were certain limits to the improvement of measurement accuracy.

Furthermore, in conventional measurement devices, measures are taken to prevent noise such as disturbance caused by light beams other than the slit light, such as placing the entire device and the object to be measured in a dark room.
This was one of the causes of larger and more expensive equipment.

The present invention has focused on these problems and has been made with the aim of improving the measurement accuracy by the optical sectioning method with a relatively simple configuration.

Means for Solving the Problems> In order to achieve the above-mentioned object, a three-dimensional shape measuring device using a light cutting method according to the present invention includes a slit light irradiation means for obtaining a light cutting line of an object to be measured;・Two optical cutting line imaging means arranged at a distance from each other and orbiting around the object to be measured together with the slit light irradiation means while maintaining a constant positional relationship with respect to the slit light irradiation means; The processing means performs recognition processing of the three-dimensional shape of the object from the two optically sectioned images obtained by the imaging means.The processing means recognizes the difference between the recognition results of the two optically sectioned images. is within a predetermined reference value, the average value of both is used as the processing result, and when the difference between the recognition results exceeds the reference value, each recognition result is used as the processing result.

Further, in the second invention, if the difference between the recognition results exceeds a reference value, the continuity of each recognition result is determined, and the recognition result with continuity is adopted as the processing result. There is.

In addition, in each of the above inventions, the case where the difference in recognition results exceeds the reference value includes not only the case where the difference between the obtained data is large but also the case where one of the data is missing.

FIG. 1 is a diagram showing the configuration of the present invention, where A is a slit light irradiation means, B□ and B2 are optical cutting line imaging means, C is a processing means, D is an object to be measured, and E is a rotating device. Note that the rotation of the slit light irradiation means A and the optical cutting line imaging means B and B2 is relative to the object to be measured, and the light irradiation means A moves around the fixed object to be measured. Alternatively, the light irradiation means A and the imaging means B 11B2 may be fixed and the object to be measured may be rotated at that position. F is an external synchronizer for synchronizing the operations of each of the above means, G is a storage device that stores the output of the processing means C, and H is an output device that outputs the data stored in the storage device G as necessary. It is.

Effect> Each imaging device images the light cutting line from a different direction, and the probability that a blind spot will occur in both imaging devices at the same time is very small compared to when there is only one imaging device. It becomes possible to increase the above-mentioned angle θ to a certain extent, and it becomes easy to improve measurement accuracy. In addition, the three-dimensional shape is recognized based on the average value of the optically sectioned images obtained by each imaging means, and if there is a large difference in the recognition results, the individual results are separated and output as they are, so the data from one imaging means is Even if there is an abnormality in the other imaging means, it is possible to supplement the data with the other imaging means.

In addition, in the second invention, when the difference in recognition results is large, the recognition result with continuity is adopted, so even if there is an abnormality in the data of one imaging device, the data can be automatically transferred by the other imaging device. is supplemented by

Therefore, the probability of being affected by noise is low, and data with no or few missing points can be obtained.
Measurement becomes possible without the need for a special dark room, and measurement accuracy is improved.

<Example> Next, an example shown in the drawings will be described. FIG. 2 is a plan view showing an outline of the apparatus, FIG. 3 is a block diagram, and FIG. 4 is a flowchart I of the control procedure.

In FIG. 2, l is a light source which is a slit light irradiation means;
2a and 2b are imaging cameras which are optical cutting line imaging means; 3;
is the object to be measured.

The light source 1 is arranged in a position to emit a slit light 4 that spreads in a direction perpendicular to the plane of the drawing including the origin ○ on a circumference 1' with a radius r centered on the origin O, and is always facing the origin 0. It is provided to rotate at a predetermined speed on the circumference 1'. Further, the imaging cameras 2a and 2b are placed at positions equidistant from the light source 1 on the tangent to the circumference 1' passing through the light source 1 at an angle θ with respect to the light g1, and always face the origin O. It is provided to rotate together with g1.

The above θ is selected to be 45°, for example. Further, the object to be measured 3 is fixed at a position including the origin ○, and each of the imaging cameras 2a and 2b is configured so that the optical cutting line 5 generated on the object to be measured 3 by the slit light 4 is included in its field of view. ing.

As the light source 1, the same type of light source as that used in the three-dimensional shape fllff determination apparatus using the conventional light cutting method can be used as appropriate, and as the imaging cameras 2a and 2b, the light source using the conventional light cutting method can be used. A device used in a three-dimensional shape measuring device, such as a COD camera, can be used as appropriate.

In the block diagram of FIG. 3, 6 is an image processing device, 7 is a rotation drive unit, and 8 is an output device. The main part of the image processing device 6 is composed of a computer, which includes a CPU 61 which plays a central role in calculations and various controls, a ROM 62 which stores control programs, etc., and a RAM which stores various data obtained.
63, a clock circuit 64 that generates a synchronization signal, and other appropriate input/output circuits (not shown). Further, the rotation drive unit 7 is appropriately configured to drive the light source 1 and the imaging cameras 2a and 2b in response to a control signal from the image processing device 6. Furthermore, the output device 8 outputs the data of the three-dimensional shape recognition result obtained by the image processing device 6, and is comprised of, for example, a CRT display or a printer.

The measuring device of this example is configured as described above,
First, the operation of the first invention will be explained with reference to the flowchart shown in FIG.

Each imaging camera 2a, 2b is controlled by a synchronization signal, and first, in step S1, respective image signals, that is, optically cut images 5a, 5b are inputted alternately. This manual switching is performed, for example, every 1/30 seconds. Step $
2, in order to enable high-speed signal processing, the optically sectioned image 5
a, 5b are binarized by a comparator, and step S3
The binarized data 51a and 51b are processed to calculate the position on the three-dimensional coordinates of the surface of the object to be measured 3, and three-dimensional coordinate recognition results 52a and 52b are obtained. In addition.

Since the width of the light cutting line 5 varies depending on the distance between the light g1 and the object to be measured 3, the slope of the surface, etc., the calculation is performed to detect the coordinates of the pixel forming the center of the line. This step S
The process in step 3 is based on the radius r centered on the origin O and the slit light 4.
The angle J of the imaging cameras 2a and 2b with respect to J! Since jtO is known, it can be suitably carried out using known procedures commonly used in conventional photosection methods.

In step S4, the coordinate data of each point obtained as the above recognition results 52a and 52b is compared with the coordinate data obtained by the other camera immediately before it, and if the difference between the two is within a preset reference value, step In S5, the average value of both is calculated and outputted as the processing result 53. Further, if the difference exceeds the reference value, in step S6, the respective recognition results 52a and 52b are used as they are as the processing result 53a.
.

53b, and both data are separated and output. The above processing is performed sequentially for each point on the surface of the object to be measured 3, and these output data are stored in the RAM 63 in step S7.
It can be prepared for future use.

Therefore, when the averaged processing result 53 is output, it is possible to obtain a measurement result with higher reliability and accuracy than when a single conventional camera is used.

In addition, if the difference between the recognition results 52a and 52b exceeds the reference value and the processing results 53a and 53b are output as they are, for example, an engineer compares the results output by the output device 8 and selects the results. The procedure for selecting and discarding images is written into a program and processed by the image processing device 6. This makes it possible to mutually complement the measurement results obtained by the imaging cameras 2a and 2b, and the probability of not being able to obtain any measurement results is significantly reduced compared to conventional devices. . In addition.

In this way, the difference between the recognition results 52a and 52b exceeds the reference value, for example, when noise due to disturbance is superimposed on the output of one of the imaging cameras, or when a blind spot occurs in one of the imaging cameras and the optical cutting line This is the case when a part of the image is missing.

In addition, the second invention is such that the above-mentioned selection is performed in consideration of data continuity, and when the difference between the recognition results 52a and 52b exceeds a reference value in step S4 of FIG. As shown by the broken line, the process moves to step S8, where the continuity of each recognition result 52a, 52b is determined, and the recognition result with continuity is adopted and outputted as a processing result 53'. This continuity is determined by, for example, sequentially comparing data before and after corresponding points over a certain period of time and determining whether the data fluctuations are within a certain reference value. By making an appropriate selection according to the shape of item 3, it is possible to obtain measurement results without noise or omissions.

In the embodiment, the imaging cameras 2a and 2b are arranged symmetrically on both sides of the light rA1, but the present invention also applies when the cameras are arranged asymmetrically with respect to the light source or on the same side with respect to the light source. Can be applied.

<Effects of the Invention> As is clear from the above embodiments, the three-dimensional shape measuring device of the present invention images the optical section line from different directions using two optical section line imaging means, and The three-dimensional shape of the object to be measured is recognized by the average value when the difference between the optically sectioned images is small, and from the optically sectioned images of the respective imaging means when the difference is large.

Furthermore, when there is a large difference between the optically sectioned images obtained by the respective imaging means, the three-dimensional shape of the object to be measured is recognized in consideration of continuity.

Therefore, since the average value of two optically sectioned images is used, it is less susceptible to noise, and highly accurate measurement is possible without the need for a special dark room. In addition, the probability that a blind spot will occur in both imaging means at the same time is small, and even if a blind spot occurs in one imaging means, the data can be supplemented with the other imaging means, so measurements can be made by increasing the angle with the slit light source. Accuracy can be improved.

Furthermore, when continuous data is used, the data is automatically supplemented, making it easy to obtain measurement results free from the effects of noise and omissions.

The present invention has the above-mentioned advantages, and a highly accurate three-dimensional shape measuring device using the optical cutting method can be realized at low cost with a relatively simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the configuration of the present invention, Fig. 2 is a schematic plan view of one embodiment, Fig. 3 is a block diagram, Fig. 4 is a flowchart of the control procedure, and Fig. 5 is a general method using the light cutting method. FIG. 2 is an explanatory diagram of a three-dimensional shape measuring device. 1... Light source (slit light irradiation means), 2a, 2b...
Imaging camera (optical cutting line imaging means), 3... object to be measured,
4... Slit light, 5... Optical cutting line, 6... Image processing device (processing means), 7... Rotation drive section, 8... Output device, 61... CPU.

Claims (2)

[Claims] (1) A slit light irradiation means for obtaining a light cutting line of the object to be measured, and a slit light irradiation means that is placed apart from each other and is irradiated with the slit light irradiation means while maintaining a constant positional relationship with respect to the slit light irradiation means. The three-dimensional shape of the object to be measured is recognized from the two optical section line imaging means orbiting around the object and the two optical section images obtained by each of the above imaging means, and the difference between the recognition results is calculated. If the difference between the recognition results exceeds the reference value, the average value of the two is taken as the processing result when the difference is within a predetermined reference value, and the processing means takes the respective recognition result as the processing result as it is. A three-dimensional shape measuring device using the optical cutting method. (2) A slit light irradiation means for obtaining a light cutting line of the object to be measured, and a slit light irradiation means that is placed apart from each other and is irradiated with the slit light irradiation means while maintaining a constant positional relationship with respect to the slit light irradiation means. The three-dimensional shape of the object to be measured is recognized from the two optical section line imaging means orbiting around the object and the two optical section images obtained by each of the above imaging means, and the difference between the recognition results is calculated. If the difference is within a predetermined reference value, the average value of both is used as the processing result, and if the difference between the recognition results exceeds the reference value, the continuity of each is determined, and the recognition result with continuity is adopted as the processing result. A three-dimensional shape measuring device using an optical cutting method, comprising: a processing means;