JPS6027924B2 - How to measure the shape of a flat plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the shape of an object to be inspected made of a flat plate such as a thick steel plate in the width direction and longitudinal direction using a shape measuring device using a set of optical cutting devices.

Conventionally, a device shown in FIG. 1 is known as a device for measuring the shape of a flat plate.

In FIG. 1, reference numeral I denotes an object to be inspected made of a flat plate, which is moved in the direction of arrow Y, which is the longitudinal direction of the object. A light source 2 projects a slit light 3 onto the object 1 to be inspected at an angle of 8.

Reference numeral 4 denotes a light cutting profile, which is formed at the intersection of the slit light 3 and the object 1 to be inspected.

5 is a camera for measuring the curvature of the light cutting profile 4; 6 is a display; the light cutting profile 4 is displayed as 4a by the magnification determined by the camera 5 and the desflae 6;

In such a device, the warpage of the object 1 to be inspected appears as a curvature of the light cutting profile 4, and the depth of the warp is h, and the light cutting angle (the angle between the object 1 and the slit light 3) is In short, the bending depth 1 of the optical cutting profile 4 is expressed by the following equation. 1=h/sino By setting 8 above to 90o or less, the curvature of 4 is also amplified by 1/sino times on the optical cutting profile 4, and this bending is caused by the optical Measured with a measuring device.

By the way, in such a conventional measurement method, when one set of light cutting device consisting of the light source 2, slit light 3, etc. is used, it is possible to measure only one of the width direction or the longitudinal direction of the material to be inspected 1. First, a plurality of optical cutting devices are required to measure in the width direction and the longitudinal direction at the same time. Furthermore, when the object to be inspected is moving in its longitudinal direction, the measurement in the lateral direction is performed over the entire length during this movement, but in order to simultaneously measure the object in the longitudinal direction, Install longitudinal light cutting devices at desired intervals in the width direction, or
Alternatively, scanning must be performed in the width direction without changing the light cutting angle. Providing a plurality of light cutting devices in this way not only makes the entire device complicated and expensive, but also creates space problems.

Instead of installing a plurality of light cutting devices, the slit light is cut from a line bisecting the width direction and the length direction, that is, 450
There is a method of projecting light from an oblique machine so that a profile can be created in the area, but it is difficult to separate the obtained measurement value into warpage in the width direction and length direction, and the object to be inspected is large. This has the disadvantage that it becomes difficult to create a slit beam within one plane due to problems such as diffraction. The present invention eliminates the above-mentioned conventional drawbacks, and provides a shape measuring device using one set of light cutting devices.
The present invention provides a measurement method capable of simultaneously measuring warpage in the width direction and longitudinal direction of an object to be inspected during shaping.

The method according to the present invention involves scanning the surface of a material to be inspected diagonally with a laser spot in its width direction repeatedly at predetermined time intervals, and running the material to be inspected in its longitudinal direction. The light cutting profile drawn by the resulting light spot is imaged with a television camera.

By measuring the longitudinal component of the video output of the above profile of this television camera, the depth of warpage at multiple points (X, , X2, -Xn) in the width direction of the inspected material is determined. Obtained for each scan. As a result, the depth of warpage at each point in the width direction and longitudinal direction on the material to be inspected is determined. Therefore, multiple points (X
, , X2, --Xn), the shape of the material to be inspected in the width direction can be determined. In addition, if we focus on the variation in the depth of warpage at each scanning point in the longitudinal direction of multiple points (X, , X2, 1-xn) in the width direction of the material to be inspected, The shape is required. An embodiment in which the present invention is applied to shape measurement of a thick steel plate will be described in detail below with reference to FIGS. 2 to 5.

In Fig. 2, 7 is an object to be inspected made of a thick steel plate;
It is moved in the Y direction.

8a is a laser light source, 8b is a vibrating mirror, and 9 is a laser beam, which is scanned within one plane in the direction of arrow X by the vibrating mirror 8b, and projected onto the object 7 to be inspected at an angle of 0.

10a is Caesar spot, 10b is Caesar spot 10
3A shows a trajectory created by scanning a, that is, a light cutting profile.

Reference numeral 11 denotes a video camera, which images the above-mentioned light cutting profile 10b with the width direction of the inspected object 7 being x and the longitudinal direction Y.

Reference numeral 12 denotes a control section to which the video camera 11 described above is connected, and together with the camera constitutes an XY tracker, which obtains the movement of the laser spot 10a as an output in the x-y coordinate system.

This XY tracker is well known, such as Suzuki,
Details are shown in Kurasawa's "Image Disector and its Application to Measurement Television" Television No. 25, No. 7, 1971. 13 is a monitor, and 14 is a certain localization layer in the width direction as described later, that is, x position output X of the control unit 12, .
15 represents a circuit that passes only the Y outputs of X2, X3, . . . , Xn and holds them until the next scan.

The laser beam 9 created by the laser light source 8a and the vibrating mirror 8b and the light cutting profile 10b by the object 7 to be inspected are 1/sin according to the shape of the object 7 to be inspected.
It is amplified 6 times.

The scanning of the laser beam 9 needs to be sufficiently fast compared to the moving speed of the object 7 to be inspected. For example, when the speed of the object 7 to be inspected is 6h/mjn, the scanning frequency should be 3 to 5H.
It should be about Z. The position P (x, y) within the field of view of the laser spot 10a is measured by the XY tracker having a field of view in the width direction X side and the longitudinal direction Y side, and this is converted into voltages Vx and V.
y, and measure the shape in the width direction from this voltage Vy.
A signal as shown in FIG. 3a is recorded on the recorder 15, and a profile of the shape in the width direction is also displayed on the monitor 13.

On the other hand, in order to obtain information on the shape in the longitudinal direction, the circuit 1
4, a certain localization layer in the width direction in one scan of the laser spot 9, that is, the V cutting of the voltage Vx, Vx2...Vxn(
Practically speaking, the voltages Vy at three locations (both ends and the center are sufficient) are held and passed through until the next scan, and the voltages Vy, Vy2, ... Vyn are applied in the width direction as shown in Figure 3b. The longitudinal shape of a certain localization layer is measured and recorded by the recorder 15. Next, the details of the circuit 14 described above are explained in the fourth section.
The figure and FIG. 5 will be explained.

In FIG. 4, 16 is a comparator that operates with Vx, 17 is a mono multivibrator that operates with the rise and fall of the comparator 16 for a certain period of time, and 18 is a gate circuit that passes the Vy output for only the operating time of the mono multivibrator 17. 19 is a differentiator that differentiates the output of the mono multivibrator 17 and passes only the positive pulse; 20 is a switching transistor that becomes conductive with the pulse of the differentiator 19; and 21 is a gate circuit 18 until the transistor 20 becomes conductive. 22 is an impedance conversion circuit having a sufficiently large resistance at the front stage to prevent the output of the capacitor 21 from discharging except when the transistor 20 is turned on. 23 is a smoothing circuit. The circuit 24 configured as described above with respect to the voltage Vx,
-, the circuits 24-2...24-n have voltages Vx2, .
...Vm is also configured, and these circuits 24-,...
24-2, . . . 24-n constitute the circuit 14 described above. In the above circuit 24-, the comparator 16, the monomultivibrator 17 and the gate circuit 18
Pass only the voltage Vy at the first scan voltage Vx of the laser spot 9, hold it in the differentiator 19, capacitor 21 and transistor 20 until the next scan Vx, A voltage output corresponding to the shape in the width direction X can be obtained. Voltage VX in the above circuit 24-, comparator
The output of the voltage generator 16, the output of the mono-multivibrator 17, the output of the differentiator 19, the voltage Vy, and the output of the capacitor 21 are shown in a, b, c, d, e, and f of FIG. 5, respectively. As described above, the present invention is capable of amplifying and measuring shapes that are difficult to visually or actually measure by a factor of 1/sina using the optical cutting method, and also includes a set of optical cutting equipment, an XY tracker, and an XY tracker. The hold circuit enables non-contact and highly sensitive shape measurement in the width and length directions.Furthermore, compared to conventional slit light, scanning the laser spot enables a high-intensity light cutting profile to be obtained. Measurement of the object to be inspected is also possible.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional example, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a waveform diagram explaining the operation of the one shown in Fig. 2, and Fig. 4 is a block diagram showing an example of the present invention. FIG. 5 is a block diagram showing the main parts of the device in detail, and FIG. 5 shows a time chart of the device shown in FIG. 7...Object to be inspected, 8a...Light source, 8b
... Vibration Mifu, 9... Laser beam, 10a
... Laser spot, 10b ... Optical cutting profile, 11 ... Video camera, 12 ... Control section, 13 ... Monitor, 15 ... Recorder. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. Scanning the surface of the material to be inspected diagonally with a laser spot in its width direction repeatedly at predetermined time intervals, and moving the material to be inspected in its longitudinal direction; By capturing an image of the drawn light-cutting brocoil with a television camera and measuring the longitudinal component of the video output of the above profile of the television camera, multiple points (X_1, X_2) in the width direction of the material to be inspected are
--X_n) is determined for each scan, and the shape of the material to be inspected in the width direction is measured based on the variation in the depth of warpage. Point (X
_1, .