JPS5934104A - Optical automatic dimension measuring method - Google Patents

Abstract

PURPOSE:To prevent the lowering of the precision of dimension measurement due to oscillation of an object to be measured, by dividing the shadow, which is projected to a photodetector group, into two with the center part of the shadow as the boundary and scanning these divided parts synchronously in opposite directions. CONSTITUTION:The shadow of an object to be measured 4 which is generated when the object 4 is irradiated with a parallel light 3 from a light source 1 is projected to a photodetector group 6, where many photodetectors are arranged, through a light receiving lens 5. This shadow is divided at a point (e) of the center part and is scanned. A reading part 7-1 scans operating conditions of the photodetector group 6 from the point (e) to a point (a) in order. Synchronously with this scanning, a reading part 7-2 scans operating conditions of the photodetector group 6 from the point (e) to a point (d) in order. Data obtained by this scanning are added in an operating part 8 and are compared with dimension data set in a setting part 9, and extraction of minimum and maximum data and processings such as average operation are performed in a signal processing part 10 on a basis of the comparison result to generate display and recording data. Thus, oscillation factors of the object to be measured are cancelled to obtain a more accurate dimension value of the outside diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical automatic dimension measurement method, and particularly to a method for reducing measurement errors caused by vibrations of an object to be measured.

Generally, when measuring the outer diameter and shape of steel pipes, wire rods, etc. online, a non-contact optical automatic measuring device is often used. The outline of the optical automatic dimension measurement method is explained with reference to FIG. 1. Light generated by a light source 1 is converted into a parallel light beam 6 by a projection lens 2, and this is irradiated onto an object to be measured 4. As a result, the shape of the shadow formed by the object to be measured is photoelectrically converted (converts the amount of received light into electric charges) by the light receiving element group 6 arranged in large numbers through the light receiving lens 5.

The reading unit 7 reads the operating status (on, off) of the light receiving element group B.
Scan from point d to point d and read in order, send this read data to the calculation section 8, compare the dimension data set in the setting section 9 and the measurement data from the reading section 7 x', The result is subjected to arithmetic processing such as extraction of minimum and maximum data and average calculation in the signal processing unit 10 to create display and record data.

In such optical automatic size measurement, the working status of the light receiving element group B changes every moment due to the vibration of the object to be measured 4.

Therefore, the dimensional accuracy depends on the time required to scan the entire operating state of the light receiving element group 6 from point a to point d (hereinafter referred to as scanning time).

To explain measurement errors due to vertical vibration of the object to be measured 4 with reference to FIG. 2, when the object to be measured 4 vibrates in the same direction as the scanning direction S of the light receiving element group B in FIG. The operating status of the light-receiving element is sequentially scanned, and the shadow of the object 4 to be measured is detected from point b, and this state continues until point 0, and the scanning ends at point d.

In this case, since the shadow is measured between b and c with respect to the actual size of the object to be measured 4, the measured value is larger than the actual size. This is because the object to be measured 4 is moving downward, and when scanning point 9c, the top surface of the object is moving from point b to point C, but measurement starts from point b. It is.

FIG. 2 (2) shows a case where the object to be measured 4 vibrates in the opposite direction to the scanning direction S of the light receiving element group 6, and the object to be measured 4 is scanned from point a.
A shadow on the upper surface of the object to be measured is detected at point 07, and the detection of the shadow is completed at point 07, and scanning is completed at point d. In this case, since the shape is measured between b'-01, the measured value is smaller than the actual size of the object 4 to be measured. This is due to the fact that the object to be measured is moving upward.
When 7 points are scanned, the top surface of the object to be measured 4 is from point b' to a
Although it is a point stop, the measurement starts from point b′.
It is.

In this way, the vibration of the object to be measured greatly affects the measured N degree.

Therefore, for example, when measuring the outer diameter of a pipe or wire during TFT transport, measurement errors occur due to vibration of the object to be measured. Conventionally, as a method of reducing such errors, measures have been taken to increase the sensitivity of the light receiving element and increase the scanning speed by increasing the brightness of the projector of the measuring device. However, there is a restriction on the time required for photoelectric conversion of the light receiving element, so it is not possible to shorten the scanning time to an extreme extent, and in order to improve the measurement accuracy, it is necessary to suppress the vibration of the object to be measured. As a method of suppressing the vibration of the object to be measured while it is being conveyed, there is a method using presser rolls. However, it is extremely difficult to eliminate vibrations when the object to be measured has many bends, or when the object is being transported while rotating, and the line must be stopped to obtain the desired accuracy. I had to.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for preventing a decrease in measurement accuracy due to vibration of an object in optical automatic measurement.

The gist of the present invention is to provide a method for measuring the dimensions of the object by projecting a shadow created by irradiating light onto the object to be measured onto a group of light receiving elements and scanning the group of light receiving elements. (
The present invention is an optical automatic sizing method characterized by B) synchronizing scans, (C) reversing scans, and (2) adding measured values. The details of the present invention are shown in Figures 6 to 4 below.
This will be explained with reference to the drawings.

A shadow created by irradiating parallel light rays 3 from a light source 1 shown in FIG. Scanning is performed by dividing it into two parts: from point e, which corresponds to the center of the shadow projected on light-receiving element group B, to point a at one end, and from point e to point d at the other end. The reading unit 7-1 reads the operating status of the light receiving element group 6 from point e to point a.
Scan the points sequentially. In addition, in synchronization with this, the reading unit 7-2 sequentially scans the operating status of the light receiving element group 6 from point e toward point d. That is, each scan is reversed and synchronized. The measured values of the reading units 7-1 and 7-2 are calculated by the calculation unit 8.
will be added at Further, the calculation section 8 performs a comparison operation between the dimension data set in the setting section 9 and the measurement data from the reading sections 7-1 and 7-2, and sends the result to the signal processing section 10 to extract minimum and maximum data. , performs processing such as average calculation, and creates display and recording data.

In this way, by adding the measurement values of each light receiving element group 6 in the opposite direction from point e, the vibration factor of the object to be measured is canceled out1, and the outer diameter dimension value is more accurate. can be obtained. Of course, a of the light receiving element group
Similar measurement accuracy can be obtained when measuring in the direction of 90 points from point and point d.

To explain in detail with reference to FIG. 4, if we consider a case where the object to be measured 4 is lifted below the point e of the light-receiving element in FIG. 6 is sequentially scanned, and point b, which is the upper limit of the shadow of the object to be measured 4, is detected. At the same time, the operation status of the light receiving element group B is sequentially scanned in the direction from the point e to the 94th point, and CA, which is the lower limit of the shadow of the object to be measured 4, is detected. If point e of the light-receiving element group 6 coincides with the center of the object to be measured when it is stopped, downward vibration causes e-
The same dimension becomes small, and the same dimension e-c becomes large.

Now, the dimension value between -11jl Treasure Fruit is D + e and b is A.

If the e-e method value is 13, A+B approximates D. The opposite situation is shown in Fig. 4 (?), when the object to be measured 4 vibrates in the opposite direction (upward), the value of A is large and the value of B is small.As before, A+B approximates D. .

In this way, by simultaneously scanning the light receiving element group in the direction from point e to point a and point d or from point a and point d to point e, measurement errors due to vibration of the object to be measured can be reduced. It is possible to obtain the diameter dimension. In the present invention, as a means for dividing and scanning the shadow projected on the light receiving element group so that the central part of the shadow is at the boundary, the method of dividing and scanning the shadow projected on the light receiving element group is as follows: Adjust the position of the light receiving element. Note that when scanning from both ends of the light receiving element toward point e, it is necessary to make the lengths from point e to both ends equal.

Next, examples will be shown. The measurement field of light receiving element group 6 is 200m.
, the resolution of one light-receiving element is 0.1]3 + o + binding scanning speed is 1500 ) IZ, the total number of light-receiving elements is 666
7 are required, and the readout time for 1 p1 light receiving element is 0,
The time is 1 μsec. In the conventional method, the pipe outer diameter is 160 mm.
The measured values when the pipe vibrates in the same direction as the scanning direction at an amplitude of ±5 and a frequency of 10 Hz at the hearing φ are as follows.

When the pipe is stationary, the part of the shadow created by the parallel ray 3 on the light receiving element group A is 160÷0.03=5333.333X5
333.333=35.555 The number of elements that detected shadows due to Shivibe (/15669 pieces).Converting this to the pipe outer diameter value gives 5669 X O,03=161.
It becomes 07 erasure φ.

The present invention aligns the center of the pipe with the center reference point 0 of the light-receiving element group, and divides the light-receiving element group into two groups (e.g., the center reference point e of the light-receiving element group B) into 6334 light-receiving element groups each. A split run was made in the opposite direction synchronized with point A at one end of the line and from point e to point d at the other end. In the same imaging as the conventional method, from point e to p
The result of reading the force direction at point a is point e! l) 264
The shadow of the upper limit end of the pipe was detected at the q-th element, and reading was performed in the direction of 96 points from point e, and as a result, the shadow of the lower limit end of the pipe was detected at the 2686th element from point e. Converting the measured value to pipe outer diameter value: (2649+2686)Xo, 03=160.0
5 recommendations φ.

Therefore, it has become possible to reduce measurement errors due to vibration factors to less than - compared to conventional methods.

According to the present invention, it is possible to reduce measurement errors caused by vibrations that occur due to deterioration over time, such as wear and tear of equipment for transporting objects to be measured, such as vibrations that occur during high-speed movement of objects to be measured.

As a result, it is now possible to perform measurements that were previously performed by stopping the line or transmitting at low speed due to low measurement accuracy during transportation, improving measurement work efficiency, and eliminating various negative effects on upstream and downstream processes due to line stoppages, etc. Ru.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional optical automatic size measuring device, FIG. 3 is a block diagram of an optical eye size measuring device to which the present invention is applied, and FIGS. 2 and 4 are diagrams explaining the present invention. It is. 1: Light source, 2: Light projecting lens, 6: Parallel light beam, 4: Measured object, 5: Light receiving lens, 6: To light receiving element 7: Reading unit, 8:
Arithmetic unit, 9 = stage setting, 10: signal processing unit. Applicant Nippon Steel Corporation

Claims (1)

[Scope of Claims] A method for measuring the dimensions of a fixed object by projecting a shadow produced by irradiating the object with light onto a group of light-receiving elements and scanning the group of light-receiving elements, comprising: (5) a light-receiving element; (B) Synchronize each scan; C) Reverse each scan direction; (C) Add each measurement value. An optical automatic measurement method characterized by: