JPH04301707A - Noncontact type volume measuring device - Google Patents

Abstract

PURPOSE:To enable accurate measurement of the volume of an uneven part in a noncontact manner by achieving the three dimensional processing of the uneven part volume of a part or the like by means of a range finder (comprised of a laser slit light source and a CCD TV camera). CONSTITUTION:A laser slit light 2 is projected from a laser slit light source 9 on an object 3. The projected light 2 makes the image of the uneven surface matched with the actual surface shape to be risen over the object 3. The light 2 over the surface of the object 3 is taken in as a slit image by means of a CCD TV camera 10, and stored in an image memory in an image processing device 7. The three dimensional coordinates data from the specified coordinate are calculated for respective points of the slit image in the device 7, and these data are transferred to a microcomputer 6. The volume of one slit on the slit projection position is calculated from these data by means of the microcomputer 6. Then, a slight movement is made of an X-axis table 4 is made through the microcomputer control. The volume of the respective slit is calculated for the whole top surface of the object 3, and the volume of a recessed part is obtained through integration of one slit volume.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The invention of this application relates to a non-contact volume measuring device that can measure the volume of concave or convex parts of parts (for example, the volume of a piston combustion chamber), the internal volume of a container, etc. It is something.

0002

[Background Art] Conventionally, as a method for accurately measuring the internal volume of a container, for example, a liquid (particularly water) is poured into a container, and the amount of water added until the container is filled is determined as the internal volume of the container. was being carried out. However, when containers are measured one after another in the production process, and it is necessary to discard the water and dry the containers after each measurement, the above method requires drainage equipment or collection equipment for the used water, and Container drying equipment is also required. This method of measuring volume using water has disadvantages in that it requires large equipment and requires additional equipment and time for drying.

[0003] There is also a method of measuring volume using a similar method using gas instead of water (air volume tester).
(See Japanese Patent Application No. 63-223529). However, since gas is compressible, volume measurement using gas is easily affected by the pressure of the gas, and has a large effect on temperature.In addition, gas has a lower viscosity than water, so the container itself Gas leakage at the connection between the container and the measuring device had a significant effect, making highly accurate measurements difficult. Further, the air volume tester described above calculates volume from pressure using Boyle's law PV=cost, but this only holds true when the temperature is constant. Therefore, the air temperature in the reference container and the air temperature in the test container must be equal, and if the temperatures in the test containers are constant, the air temperature in the test containers will naturally change, and the temperature in the reference container will change. A temperature difference between the air temperature and the air temperature causes an error. Furthermore, since the temperature difference changes, for example, in summer and winter, or during the day and night, it is impossible to maintain constant temperature control between the reference container and the measured container in an actual production line. In addition, since air is a compressible fluid, the air volume tester takes time to inject into the container, and it is difficult to seal, making it unsuitable for in-line measurement.

0004

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems of conventional volume measuring devices that measure volume using water or gas by using a range finder to measure the volume of uneven parts, etc. It is an object of the present invention to provide a non-contact volume measuring device that can accurately measure the volume of an uneven portion without contact by performing three-dimensional image processing.

[0005]

[Means for Solving the Problems] Therefore, the first technical means adopted by the present invention to solve the above-mentioned problems is a moving table for moving a measuring device measuring object a predetermined distance in a predetermined direction;
A slit light source that irradiates the object to be measured with slit light, a camera that takes a slit image when the slit light output from the slit light source hits a non-measurement object, and a three-dimensional image obtained from the slit image obtained from the camera. A non-contact volume measuring device is constructed from image processing means having a function of image processing data, calculating the volume for each slit image, and integrating these to obtain the entire volume. In addition, the second technical means adopted by the present invention is to project slit light onto the object to be measured from a slit light source, capture the slit light on the surface of the object as a slit image with a television camera, and create a predetermined image based on the captured slit image. Calculate three-dimensional coordinate data from the coordinates, calculate the volume of one slit at the slit projection position using this data, then calculate the volume of each slit by the same procedure as above while moving the measurement object, and then calculate the volume of each slit at the slit projection position. The purpose is to obtain the volume to be measured without contact by integrating the volume of one slit.

[0006]

[Operation] First, the laser slit light source of the range finder projects a laser slit light onto the object. The projected slit light highlights an uneven surface that matches the surface shape of the object. Laser slit light on the surface of an object is captured as a slit image by a CCD television camera in a range finder and stored in an image memory in an image processing device. Three-dimensional coordinate data is calculated from predetermined coordinates for each point on the slit image within the image processing device, and this data is transferred to a personal computer. The volume of the slit projection position (one slit volume Vc) is calculated from the three-dimensional coordinate data on the slit obtained in the personal computer. In order to perform the same procedure as above, the X-axis table is slightly moved (ΔX) by computer control. Once the volume of each slit (i=0 to m) has been calculated for all the top surfaces of the object to be measured, the measurement is finished, and the recess volume V is determined by integrating all the slit volumes.

[0007]

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a volume measuring device according to the present invention, FIG. 2 is a schematic block diagram of a range finder, and FIG. 3 is a schematic block diagram of a range finder. FIG. 3 is a diagram showing the shape of a non-measurement part by a range finder.

In FIG. 1, 1 is a range finder, 2 is a range finder, and 2 is a range finder.
is a laser slit light, 3 is a non-measurable object (target object), 4 is an X-axis table that moves the target part in the X-axis direction, 5 is an X-axis driver, 6 is a microcomputer, 7 is an image processing device, 8 is a black and white monitor These constitute the non-contact volume measuring device of this embodiment.

Next, each component will be explained. As shown in FIGS. 2 and 3, the range finder 1 is composed of a laser slit light source 9 and a CCD television camera 10. A camera captures a slit image when the slit light hits an object to be measured, and an image processing device extracts three-dimensional data on the slit in the slit image obtained from the camera. The X-axis table is used to scan the object, and has the function of minutely moving the object in the X-axis direction by an X-axis driver 5 by a predetermined distance. Furthermore, the microcomputer 6 and the image processing device 7 calculate the volume based on the above-mentioned three-dimensional image data by a method described later, and have a function of calculating the volume of each slit image and integrating these to obtain the entire volume. have.

Next, a specific volume measuring method using the non-contact volume measuring device configured as described above will be explained based on the flowchart of FIG. 4, taking an object as shown in FIG. 5 as an example. . 1) When the program starts, first, the range finder's laser slit light source projects a laser slit light onto the object. As shown in FIG. 3, the projected slit light highlights an uneven surface on the object that matches the surface shape of the object (step 100). 2) The laser slit light on the surface of the object is captured by the CCD television camera in the range finder as a slit image as shown in FIG. 3, and stored in the image memory in the image processing device (step 101). 3) Perform three-dimensional coordinate data calculation from predetermined coordinates for each point on the slit image within the image processing device, and transfer this data to a personal computer. Specifically, there are approximately 480 points on the slit image, and the distance of each of these points from the reference height is calculated, and this data is transferred to the personal computer (step 102). 4) From the three-dimensional coordinate data on the slit obtained in the computer, the volume of the slit projection position (one slit volume V
c) is calculated (step 103). 5) In order to perform the same procedure as 1) to 4) above, the X-axis table is slightly moved (ΔX) by computer control (step 104). 6) When the volume of each slit (i=0 to m) is calculated for all the top surfaces of the object to be measured, the measurement is finished (step 105), and the following equation is obtained by integrating all the slit volumes. The recess volume V is determined by (step 106).

[Math 1]

In the above manner, the volume of the concave or convex portion of the object can be determined. Here, the reference height used for calculating the slit volume and the calculation of one slit volume will be explained in more detail.

When the laser slit light is projected as shown in FIG. 5, the cross-sectional view of the object for the i-th slit light is as shown in FIG. (Here, Y-Z coordinate data from j=0 to n is obtained for the i-th slit image). Based on FIG. 6, the reference height Zav and 1 are calculated using the following method.
Calculate the slit volume Vi. 1) Calculation of reference height Zav in FIG. 6. Positive direction dZj [=Zi+p −Zi] from j=0
are calculated sequentially, and the first point where dZj > q (q is set arbitrarily depending on the workpiece shape) (the position where the shape changes) is set to j1.
(point A in the figure), and d in the negative direction from j=n.
Sequentially calculate Z(-j) [=Zj-p -Zj], and find the first point where dZ(-j)>q (the point where the shape changes) as j
2 (point B in the figure). From the above, the average height Zav can be calculated using the following formula.

[Equation 2] 2) Calculation of 1 slit volume Vi. Using the Zav (reference height) determined above, the amount of one pitch of the slit required to calculate the volume of one slit is determined by the following formula.

[Equation 3] ΔX=Xi + 1 −Xi Next, the height of each point in FIG. 6 (distance from the reference height and distance between each point) is determined by the following equation.

[Math. 4] ΔYj = Yj + 1 - Yj

[Mathematical 5]ΔZj
=Zj-Zav The volume of one slit is determined from the above formula, and the total volume can be determined by integrating the volume using the following formula.

[Math 6]

Although the above embodiment measures the volume of a concave portion, a convex portion can also be determined in exactly the same manner. Further, depending on the object, the slit light becomes a blind spot, and data may not be obtained in some cases, but it is possible to generate data if correction is performed using the preceding and following data as shown in FIG. Furthermore, since the present invention allows volume to be measured in a non-contact manner as described above, it is considered to be particularly effective for objects that are deformed due to pressure, such as sand molds.

[0014]

[Effects of the Invention] As described above in detail, according to the present invention, the following excellent effects can be achieved. 1. Since it is possible to measure without contact, it is possible to measure objects made of materials and shapes that are easily damaged. 2. Measurement is possible even when the object is tilted. (This is not possible with methods using gas or liquid.)3. In the production process, liquid methods require equipment for drainage, drying of the workpiece, etc., and bubbles tend to remain, making automation difficult.However, the present invention has a simple configuration and can be automated. 4. Air volume testers are affected by workpiece temperature changes on the production line, but the present invention can measure without being affected.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a volume measuring device as an embodiment of the present invention.

FIG. 2 is a configuration diagram of a range finder.

FIG. 3 is a diagram showing the shape of a part to be measured by a range finder.

FIG. 4 is a volumetric flowchart diagram.

FIG. 5 is a diagram showing a position where a laser slit is projected onto an object.

FIG. 6 is a cross-sectional view of the workpiece.

FIG. 7 is an explanatory diagram of data correction for blind spots.

[Explanation of symbols]

1 Range finder 2 Laser slit 3 Work 4 X-axis table 5　X-axis driver 6. Microcomputer 7 Image processing device 8. Black and white monitor 9 Slit light source 10, 14 TV camera 11 Laser slit light 12 Slit position 13 Object

Claims (2)

[Claims] Claims: 1. A moving stage for moving a measured object a predetermined distance in a predetermined direction; a slit light source for irradiating the measured object with slit light; a camera for taking a slit image; and an image processing means having a function of processing three-dimensional data from the slit image obtained from the camera, calculating the volume of each slit image, and integrating these to obtain the entire volume. A non-contact volume measuring device comprising: 2. Projecting slit light onto the object to be measured from a slit light source, capturing the slit light on the surface of the object as a slit image with a television camera, and calculating three-dimensional coordinate data from predetermined coordinates based on the captured slit image. The volume of each slit at the slit projection position is calculated using this data, and then the volume of each slit is calculated using the same procedure as above while moving the object to be measured.
A non-contact volume measurement method characterized by determining the volume to be measured by integrating the slit volume.