JPS60218005A - width measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a width measuring device suitable for measuring the width of concave and convex portions formed on the surface of an object in a non-contact manner.

[Background of the invention]

Conventionally, there have been two methods for non-contact measurement of concave and convex rings on the surface of an object: a magnetic method and an optical method.

The magnetic type uses a sensor 2 having an iron core 3, an excitation coil 4, and a detection coil 5 to detect the part to be measured (
“The illustrated example attempts to measure the width E of a concave portion 1 on the surface of an object, and this method is based on the principle that the magnetic flux f passing through the portion 1 to be measured is
Since changes in the amount of are used, variations in measured values are likely to occur depending on the depth of the concave portion and the height of the convex portion, which are the portions to be measured. In addition, if the first position deviates slightly, measurement becomes impossible, and the tolerance for deviations in the relative positions is small, so it is difficult to apply when the positional relationship between the part to be measured and the sensor is unstable. As shown in the figure, the width l of the part to be measured (the illustrated example is a concave part on the surface of an object) 1 is measured from the optical image formed on the light receiving surface of the imaging device (image sensor) 6. The difference in height between the measurement part 1 and the surrounding surface is small,
When the surface conditions are almost the same, if the object surface is uniformly illuminated as usual, there will not be enough contrast between the light and dark between the part to be measured 1 and the surrounding surfaces, so this method is not suitable for width measurement. was difficult.

[Purpose of the invention]

The purpose of the present invention is to measure the width of concavities and convexities on the surface of an object with a small height difference and almost the same surface condition with high precision (non-contact), and to determine the relative position of the part to be measured. It is an object of the present invention to provide a width measuring device that is not easily affected by deviations in width.

[Summary of the invention]

The present invention provides an imaging device in which a light-receiving section is installed so as to face concavities and convexities on the surface of an object to be measured and to be parallel to the width direction of the object to be measured, and each rising surface of the object to be measured during measurement. a light source that projects light from different directions onto the part to be measured so as to produce a shadow; and a signal processing means that detects the positions of both ends in the width direction of the part to be measured based on the level difference in the output signal of the imaging device.
This width measuring device is characterized by comprising a calculation means for calculating the width dimension between these two positions.

[Embodiments of the invention]

First, the principle of the present invention will be explained with reference to FIGS. 3 to 6.

FIG. 3 is a diagram showing the positional relationship between the imaging device, the light source, and the part to be measured. The light receiving part 7 of the image sensor, which is the imaging device, is placed opposite the part to be measured (the illustrated example is a concave part on the surface of the object) 1. Part 1
The light sources 8 and 9 are located in symmetrical positions with respect to the light receiving part 7 on the same plane as the light receiving part 7 and the part to be measured 1, and are different from each other with respect to the part to be measured 1. It is arranged to project light from all directions. 1o is a lens for forming an optical image of the part to be measured 1 on the light receiving part 7;
, 12 homogenizes the light emitted by the light sources 8 and 9 and outputs it to the part to be measured 1.
It is a lens for exposing the Although the type of sensor element constituting the light receiving section 7 does not matter, here, the number of light receiving sections 7 is n (
For example, 2,048 photoelectric conversion elements are arranged in a row,
It is assumed that the photodiode array is composed of a photodiode array that extracts charges accumulated in each element in accordance with the amount of incident light as temporally serial voltage signals by scanning.

The measurement may be carried out by turning on the left and right light sources 9 sequentially, or by turning on the left and right lights simultaneously; the former case will be described here.

Now, when the left light source 8 is turned on, the light 13 emitted from the light source 8 casts a shadow 15 on the left rising surface I in the recess (groove) 1, which is the part to be measured, as shown in FIG. 4(A). arise. Therefore, a strong contrast between light and dark as shown in FIG. 4(b) appears between the recess 1 on the surface of the object and the surrounding surfaces, and the left end A of the recess 1 becomes the boundary between bright and dark. At this time, an image of the recess 1 is focused on the light receiving section 7 depending on the intensity of the reflected light, so the photoelectric conversion element constituting the light receiving section 7 has bright and dark images corresponding to the left end A of the recess 1 as shown in FIG. The boundary A' is stored as accumulated charge. The position of this bright and dark boundary A' is at the light receiving part 7.
It can be easily detected by the step difference in the output signal obtained by scanning. Next, when you turn on the light source 9 on the right side,
As shown in FIG. 5(a), the light 14 emitted from the light source 9 creates a shadow 16 of the right rising surface IB within the recess 1. For this reason, there is a gap between the recess 1 on the object surface and the surrounding surface as shown in Fig. 5 (b).
A strong contrast between light and dark appears as shown in the figure, and the concave part 1
The right edge B is the boundary between light and darkness. At this time, the light and dark boundary B' corresponding to the right end B of the recess 1 is stored as an accumulated charge in the photoelectric conversion element constituting the light receiving section 7, as shown in FIG. 6, and the position of this bright and dark boundary B' is Similarly to the above, the light receiving section 7
It can be easily detected by the step difference in the output signal obtained by scanning. Since the spacing between the elements of the light receiving section 7 is precisely defined by IC manufacturing technology, the converted value ε per bit determined by the number of elements (number of bits) between the detected two positions A' and B' and the image magnification is By applying the fins, the width of the recess 1 can be determined.

In this way, the width measuring device according to the present invention projects light from different directions so as to create shadows of each rising surface of the measured part during measurement, thereby measuring the distance between the measured part and the surrounding surfaces of the object surface. The contrast between light and dark is added to the image pickup device, making it easy for the image pickup device to detect the positions of both ends in the width direction of the part to be measured.
If a high-resolution image sensor such as 48 bits is used, the width can be accurately measured regardless of the difference in height or surface condition between the part to be measured and the surrounding surfaces.

Although FIGS. 3 to 5 show the case where each rising surface of the recess 1, which is the part to be measured, is perpendicular to the surrounding surface, FIG. As shown, by making the incident angle θ of the light 14 from the light source smaller than the inclination angle of the rising surface IB, a shadow 16 can be generated on the rising surface IB, and a shadow can be similarly generated on the rising surface IA. Therefore, the width can be measured from both images. Furthermore, even if the part to be measured is a convex part, as shown in FIG. By taking an image in a state where this occurs, the width between the two points A and B can be measured. The present invention can also be applied to measuring the width of the four parts 10 caused by the gap between the abutting ends of the upper layer of a laminate as shown in FIG. The object surface on which concavities and convexities are formed is limited to a flat surface, which is the part to be measured that is imaged in a state where the shadow 16 of the applied rising surface IB is produced and a similar rising surface IA, 17) where a shadow is produced. It may be a curved surface such as a cylindrical surface without any problem. Furthermore, any material that does not allow light to pass through the object can be measured.

In this case, the part to be measured 1 is well within the field of view of the imaging device that can be read through the lens 10, and is less susceptible to the effects of displacement in relation to the part to be measured than the magnetic sensor shown in FIG. Therefore, it can be applied even when the positional relationship with the part to be measured is unstable.

Next, one embodiment of the present invention will be specifically described with reference to FIGS. 10 to 12.

FIG. 10 is a block diagram showing the system configuration.

Reference numeral 17 denotes a light receiving section and a scanning circuit for extracting a video signal, and the imaging device 17 and the projecting light sources 8 and 9 are mounted on one support plate 18 so as to be in a predetermined relative position with respect to the part to be measured 1. It is. Here, the light source 8-29 is made movable along the arc-shaped guide grooves 19, 20 provided on the support plate 18, and can be fixed at any position with a fixture (not shown). The incident angle of light can be adjusted depending on the shape and dimensions. 21 is a control unit (sequencer) that executes a measurement sequence according to a set program;
2.23 is an address setting switch for detecting the positions of both ends in the width direction of the part to be measured 10; 24 is an address switching relay operated by a command from the control unit 210; 25 is a light source switching relay; 26 is an output signal switch for the image pickup device 17; F) Measured part 1 by amplification, slicing processing, mask processing, bit counting, etc.
The signal processing section is a signal processing means for detecting the positions of both ends in the width direction, and includes a variable resistor 27 for setting a slice level and a BCD switch 29 for setting the number of mask bits. 3
0 is an arithmetic unit that is an arithmetic means for calculating the width dimension of the part to be measured 10 based on the output data of the signal processing unit 26, and 31 is a display unit that numerically displays the measurement results.

FIG. 11 shows the process of signal processing carried out in the signal processing section 26. After amplifying the raw data (inverted signal) output from the imaging device 17 when the light sources 8 and 9 are turned on left and right sequentially, slicing is performed to extract only signals above the slice level set by the variable resistor 27 and generate a pulse waveform. Convert to Since the slice-processed data contains unnecessary signals corresponding to dark areas on the surface of the object other than the part to be measured, mask processing is performed next, and the signals are set by the BCD switches 28 and 29 from both ends of the image sensor field of view. Eliminate unnecessary signals within the range of mask bit numbers Yl and Y2. As a result, only the signals corresponding to the shadows of each rising surface of the part to be measured 1 remain. After mask processing, when the left light source is turned on, the interval between ■ and ■ set by the address setting switch 22,
That is, the address counter counts the number of bits a from one end of the field of view of the image sensor (■ bit) to the rising point of the signal (■ bit). This means that the left end position of the image of the part to be measured (A' in FIG. 6) has been detected. When the right light source is on, the address counter measures the number of bits between ■ and ■ set by the address setting switch 23, that is, the number of bits from one end of the image sensor field of view (■ bit) to the falling point of the signal (■ bit). Count. This means that the right end position of the image of the part to be measured (B/ in FIG. 6) has been detected, and these two bit numbers a and b become the output data of the signal processing section 26.

FIG. 12 is a flowchart showing the operational relationship among the control section 21, signal processing section 26, and calculation section 30.

In the measurement, the control section 21 first instructs the light source switching relay 25 to turn on the left side of the light source in step 101. As a result, the light 13 emitted from the light source 8 hits the part to be measured 1 .

Next, in step 102, a command is given to the address switching relay 24 to select the addresses ``--'' set by the address setting switch 22. Then, the signal processing section 26 performs step 20.
1, process the output signal of the imaging device 17 as described above,
Output the number of bits a between ■ and ■.

At this time, the control unit 21 waits for the set time of the timer to elapse in step 103, and then proceeds to the next step 104.

T1 is the time required for signal processing, and is set to about 1 second, for example. In step 104, a measurement start signal is output, and in response to this signal, the arithmetic unit 30 reads and stores the number a of pits between ■ and ■ in step 301, and then outputs a measurement end signal in step 302. Based on this signal, the control unit 21 instructs the light source switching relay 25 to turn off the left light source in step 105, and then to turn on the right light source in step 106. As a result, the light 14 emitted from the light source 9 instead of the light source 8 hits the part to be measured 1 . Next, in step 107, the control unit 21 instructs the address switching relay 24 to select the address O-■ set by the address setting switch 23. Then, in step 202, the signal processing means processes the output signal of the imaging device 17 as described above, and outputs the number of bits between ■ and ■.

At this time, the control unit 21 performs the step 1 in step 108.
As in 03, the process waits for the elapse of the set time T+ of 17, then proceeds to the next step 109, and outputs a measurement start signal. In response to this signal, the calculation unit 30 reads and stores the bit number between ■ and ■ in step 303, and then outputs a measurement end signal in step 304. Based on this signal, the control unit 21 instructs the light source switching relay 25 to turn off the right light source. The calculation unit 30 further proceeds to step 305 and performs the calculation of (ba) ε=1 (ε: converted value per pit, !=width dimension of the part to be measured), and then in step 306 calculates the measured value! Check and if there is no abnormality, proceed to step 307 and check the measured value! The display section 31
to be displayed. The output data of the calculation unit 30 can also be used as data for controlling a manufacturing device that determines the width dimension of the part to be measured, and as data for selecting products.

Although the address switching relay 24 and the light source switching relay 25 may be operated manually, automation of measurement can be realized by operating them according to commands from the control section 21 programmed as described above.

Next, an embodiment will be described in which the width is measured by turning on the left and right light sources simultaneously.

For example, as shown in Fig. 13(A), if light 13.14 of the same color emitted from the left and right light sources (not shown) is simultaneously applied to the recess 1 on the surface of the object to be measured, the light inside the recess 1 Penumbra 15' due to left and right rising planes IA and IB, ! 6' occurs, a bright and dark contrast as shown in Figure 13 (B) appears between the recess 1 on the object surface and the surrounding surfaces, and the left and right ends A and B of the recess 1 become the boundary between bright and dark. .

Therefore, if a sensitive imaging device is used, the positions of the left and right ends A and H can be sufficiently determined from the output signals thereof, and the width can be measured.

In addition, the color of the light emitted from the left and right light sources is different, and the first example is
Figure 4 (A) When the green light ◎ emitted from the left light source and the red light ■ emitted from the right light source are simultaneously applied to the recess 1 on the surface of the object, which is the part to be measured, as shown in Fig. A red shadow 15'' is generated in the shaded portion of the left rising surface IA where the red light ■ is blocked, and a green shadow 16'' is generated in the shaded portion of the right rising surface IB where the red light ■ is blocked.Recessed portion 1 Since both the green light 〇 and the red light ■ strike the surrounding surface, when the filter 32 provided on the front of the imaging device (not shown) is switched to allow only the green light to pass through, the image shown in Fig. 14 (b) is obtained. An image having a contrast between bright and dark as shown in FIG. 14(C) is captured, and when only red light is transmitted, an image having a contrast between light and dark as shown in FIG. 14(C) is captured.

Therefore, the positions of the left and right ends A and B of the concave portion 1, which are the boundaries between brightness and darkness of each image, are detected using the same signal processing means and calculation means as in the embodiment shown in FIGS. 10 to 12, and the width is measured. can be done. That is, in this example, it is better to switch the filter instead of switching the light source left and right.

〔Effect of the invention〕

According to the present invention, by projecting light from different directions, shadows are created on the rising surfaces of the concave and convex portions of the object surface, which is the part to be measured, and the contrast between the left and right ends of the part to be measured is defined on the object surface. Imaging is performed with a forced contrast of
The configuration is such that the width is measured by detecting the positions of both ends in the width direction of the part to be measured from the step difference in the video signal obtained as a result.
Even if the difference in height between the part to be measured and the surrounding surfaces is small and the surface conditions are almost the same, the width can be easily measured, and the accuracy is not affected by the difference in height between the part to be measured and the surrounding surfaces. Good measurement results can be obtained. Further, since there is no problem even if the position of the part to be measured shifts within the field of view of the imaging device, it can be applied even when the positional relationship of the part to be measured with respect to the measuring device is unstable.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams of conventional width measurement techniques;
The figure is an explanatory diagram showing the positional relationship between the light receiving section of the imaging device, the projecting light source, and the part to be measured in the present invention. Figures 4 and 5 show the occurrence of shadows on the part to be measured when the light sources are turned on sequentially from left to right. An explanatory diagram showing the state, FIG. 6 is a plan view of the light receiving section of the imaging device, and FIGS.
FIG. 9 is a sectional view showing another example of the part to be measured, FIG. 10 is a block diagram showing an embodiment of the present invention, FIG. 11 is a chart showing the signal processing process in this embodiment, and FIG. 12 13 and 14 are flowcharts for explaining the operation, and FIGS. 13 and 14 are explanatory diagrams showing the state of occurrence of shadows of the part to be measured in other embodiments of the present invention. 1: Part to be measured IA, IB: Rising surfaces A, B: Both ends in the width direction 7: Imaging device light receiving section 8.9:
Light sources 15, 15', 15", 16, 16', 16
”: Shadow 17: Imaging device 26: Signal processing means 30: Computing means Attorney Junnosuke Nakamura 9

Claims (1)

[Claims] The imaging device is installed so that the light receiving part faces the concave and convex parts of the surface of the object to be measured and is parallel to the width direction of the object to be measured. a light source that projects light from six different directions onto the measurement target part, a signal processing means that detects the positions of both ends in the width direction of the measurement target part based on a step difference in the output signal of the imaging device;
A width measuring device comprising calculation means for calculating a width dimension between positions.