JPH0226058Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a surface defect measuring device, and particularly to a surface defect measuring device suitable for measuring defects on the inner peripheral surface of a cylindrical object to be measured.

[Background of the idea]

In conventional surface defect measuring devices of this type, a light beam from a projector is passed through a rotating mirror, etc., and the light beam is sequentially irradiated from the measurement start point to the measurement end point on the surface of the object to be measured, and the reflected light is An image sensor performs photoelectric conversion, and a processing device performs arithmetic processing on the output of the image sensor to determine the presence or absence of a defect.

The conventional device described above sequentially scans the object to be measured from the measurement start point to the measurement end point and photoelectrically converts the reflected light from the object. There was a problem in that the time required increased in proportion to the area.

[Purpose of invention]

An object of the present invention is to provide a surface defect measuring device that can shorten measurement time.

[Summary of the idea]

The present invention includes two measuring heads that are integrally provided along the inner circumferential surfaces of two adjacent objects to be measured, each detecting the reflected light of the light irradiated onto the inner circumferential surfaces of these objects. The difference between the detection outputs of these two measurement heads is determined, the difference is compared with a preset reference voltage, and the presence or absence of a defect on the inner circumferential surface of the object to be measured is determined based on the comparison result. It is configured as follows.

That is, the present invention measures surface defects at high speed by performing analog processing on the detection output of the measurement head to determine the presence or absence of defects on the inner peripheral surface of the object to be measured.

[Example of idea]

Embodiments of the present invention will be described based on the drawings. FIG. 1 shows the configuration of an embodiment of a surface defect measuring device according to the present invention. In the same figure, 1A, 1
Reference numeral B denotes a measurement head that measures the presence or absence of defects and the presence or absence of dust etc. on the inner circumferential surface 81 of the object to be measured 80, and the measurement heads 1A and 1B are integrally fixed at a constant interval by the mounting plate 2. has been done. The configuration of these measurement heads 1A and 1B is shown in FIG. In FIG. 2, the side portion of the optical barrel 30 to which the optical system is attached, that is, the outer circumferential surface has a circumferential direction.
Four wide-angle lenses 31 are arranged at angular intervals of 90 degrees, and the reflected light from the inner circumferential surface 81 of the object to be measured 80 focused by these wide-angle lenses 31 is directed in the axial direction of the optical cylinder 30. A square pyramid-shaped reflecting mirror 32 that converts the light into parallel light is fixed to the base 33 of the optical barrel 30.

In addition, as shown in FIG. 3, a mount 34 formed on the top of the optical barrel 33 receives the reflected light from the reflecting mirror 32 and arranges each pixel in a two-dimensional matrix on a plane perpendicular to the axis of the optical barrel 30. An image sensor 5 is provided.

Now, in FIG. 1, guide parts 7A and 7B are formed on the sides of measurement heads 1A and 1B.
It is slidably fitted into rails 9, 9 formed on the left and right feed tables 12. Further, a vertical feed ball nut is formed in the guide portion 7B, and the screw rod 8 connected to the rotating shaft of the vertical feed motor 10 fixedly installed on the left and right feed bases 12 is screwed into the vertical feed ball nut. It is configured.
Further, the left and right feed bases 12 are slidably fitted into rails 16, 16 fixed to the fixed wall, and a ball screw 13 is screwed to a left and right feed ball nut 11 that is fixed to the left and right feed bases 12. There is. Both ends of the ball screw 13 are supported by bearings 15, 15 fixed to a fixed wall, and the left and right feed motor 1
4 and is configured to be rotationally driven.

Reference numerals 17 and 18 are drive circuits for driving the vertical feed motor 10 and the left and right feed motors 14, respectively. Further, 21 is a display unit that displays the measurement results of the object to be measured 80 in the form of an image or the like. Furthermore, control circuit 2
0 outputs a signal for controlling the position of the measuring head 1, and outputs a display signal for displaying the measurement result of the object to be measured 80 to the display unit 21.

Next, a specific configuration of the control circuit 20 is shown in FIG. In the figure, the control circuit 20 is connected to the measurement head 1.
Sample and hold circuits 32 and 33 that sample and hold the outputs of amplifiers 30 and 31 that amplify the detection outputs of A and 1B to a predetermined level, respectively, at a predetermined period based on the comparison timing signal S output from the synchronization signal circuit 53, respectively. a subtraction circuit 34 that subtracts each output of the subtraction circuit 34, a comparison circuit 35 that compares the output of the subtraction circuit 34 with the reference voltages V ₁ and V ₂ output from the reference voltage generation circuit, and a latch circuit 37 that holds the judgment output of the comparison circuit 35. , 38, an OR circuit 39, a latch circuit 40, an oscillator 50 that outputs a reference clock pulse, frequency divider circuits 51 and 52 that divide the clock pulse signal of the oscillator 50 to a predetermined frequency division ratio, and outputs of the frequency divider circuits 51 and 52. a synchronizing signal circuit 53 which outputs a comparison timing signal S of a predetermined period in response to the received signal;
and a processing circuit 60 that performs arithmetic processing to be described later. Next, a specific configuration of the processing circuit 60 is shown in FIG. In the figure, a processing circuit 60 includes image signal interfaces 41A and 4 for storing image signals from measurement heads 1A and 1B in predetermined memory areas of frame memories 42A and 42B.
1B, frame memories 42A and 42B in which image data for one screen of the display unit 21 is stored, a microcomputer 44 that performs various calculation processes,
A digital input/output port 45 takes in a measurement start command and outputs a judgment signal indicating the measurement result for driving the line, takes in each output of the latch circuits 37, 38, and 40 based on a comparison timing signal S, and sets a predetermined timing. A digital input/output port 4 outputs a reset signal 106 to each circuit section.
6. A digital output port 48 for outputting a judgment signal indicating the measurement result of the object to be measured 80 obtained through arithmetic processing by the microcomputer 44, and outputting drive signals to the vertical feed motor 10 and left/right feed motor 14, respectively. It consists of a digital output port 49 that outputs control signals for moving the measuring heads 1A, 1B to predetermined positions to the drive circuits 17, 18, respectively.

The operation of the control circuit 20 having the above configuration will be explained based on the timing chart shown in FIG.
The reference clock pulse signal outputted from the oscillator 50 is divided by a predetermined frequency by a frequency dividing circuit 51, and a horizontal synchronization signal on the screen of the display section 21 is created. Further, the clock pulse signal frequency-divided by the frequency dividing circuit 51 is further divided by a frequency dividing circuit 52 to a predetermined frequency division ratio to obtain a synchronizing signal in the vertical direction of the screen on the display section 21. The synchronization signal circuit 53 receives horizontal synchronization signals from the frequency dividing circuits 51 and 52,
Each vertical synchronization signal is taken in and a comparison timing signal S is output to each circuit section (FIG. 6a).

On the other hand, each output 90, 91 of measurement head 1A, 1B
(FIG. 6b, c) are amplified to a predetermined level by amplifiers 30 and 31, and these amplified outputs are sent to sample and hold circuits 32 and 32 at predetermined timings based on a comparison timing signal S output from a synchronization signal circuit 53. 33. (Fig. 6d,
e).

Further, the outputs A and B of the sample and hold circuits 32 and 33 are subtracted by a subtraction circuit 34, and the calculated output (A-B) is converted to the reference voltages V ₂ and V ₂ outputted from the reference voltage generation circuit 36 by a comparison circuit 35. compared to Here, the reference voltage V ₁ is the measurement head 1A, 1
The reference voltage V 2 indicates the lower limit value for the difference value between the outputs 90 and 91 of B when there is no surface defect, and the reference voltage V ₂ indicates the upper limit value for the difference value when there is no surface defect (FIG. 6f). If A-B<V ₁ in the comparator circuit 35, the latch circuit 37
The comparison signal 100 (Fig. 6g) is also A-B>
V ₂ , the comparison signal 1 is applied to the latch circuit 38.
01 (Fig. 6h) is output respectively. Furthermore
The OR circuit 39 receives each comparison signal 1 from the comparison circuit 35.
00 and 101 are input, and an output signal 102 (FIG. 6i) is output to the latch circuit 40. The latch circuits 37, 38, and 40 output a determination signal 10 for determining the presence or absence of a defect in the object to be measured 80.
3, 104, and 105 are output to the processing circuit 60, respectively. Here, the judgment signal 103 is the measurement head 1
The determination signal 104 is output when there is a defect in the inner circumferential surface 81 of the object to be measured 80 measured by the measurement head 1B, and the determination signal 104 is output when there is a defect in the surface to be measured 81 measured by the measurement head 1B. Also, the judgment signal 105
is output when there is a defect in the inner circumferential surface 81 of the object to be measured 80 measured by either one of the measurement heads 1A, 1B (FIG. 6 j to m). Each signal output from the latch circuits 37, 38, and 40 is a reset signal 106 output from the processing circuit 60.
(FIG. 6a). Here, the output 105 of the latch circuit 40 is used as a starting signal for an interrupt processing program to be described later.

Next, the contents of the program executed by the microcomputer 44 are shown in FIGS. 7 and 8.
Figure 7 shows the contents of the main routine.
In the figure, when the program is started, a measurement number counter C (this counter is a soft counter) is reset in step 200.
In the next step 202, it is determined whether or not to start measurement, in other words, whether or not a measurement start command has been input to the digital input/output port 45.
If it is determined in step 2 that the measurement start command has not been input, the same determination is repeated.

On the other hand, if a measurement start command is input to the digital input/output port 45 in step 202, the process advances to the next step 204, where the soft counter C is updated. Furthermore, in the next step 206, the control circuit 20 outputs a lowering drive signal to the vertical feed motor 10 via the drive circuit 17, and the measuring head 1
A and 1B descend from the measurement starting point along the inner circumferential surface 81 of the object to be measured 80. Further, in step 208, it is determined whether or not there is an interrupt, in other words, whether the latch circuit 40
It is determined whether the output signal (interrupt signal) 105 of is input to the processing circuit 60. Step 2
If it is determined in step 08 that there is an interruption, the execution of the main routine is terminated. On the other hand, if it is determined in step 208 that there is no interruption, the process advances to the next step 210, where it is determined whether or not the measurement of the corresponding workpiece 80 has been completed. If it is determined in step 210 that the measurement has not been completed, the process returns to step 206.
The same processing as described above is performed.

On the other hand, if it is determined in step 210 that the measurement has been completed, the process advances to step 212, where the measuring heads 1A, 1B are connected to the vertical feed motor 10 from the digital output port 49 in the control circuit 20 via the drive circuit 17. A control signal is output to raise the measuring heads 1A and 1B.
rises to the measurement start position and stops at that position.

Furthermore, in step 214, it is determined whether the contents of the measurement count counter C have reached a preset measurement count i. That is, it is determined whether or not the measurement of all the workpieces to be measured has been completed. If it is determined in step 214 that the measurement of all the workpieces has not been completed, the process moves to step 218, and in step 218, the measurement is sent from the digital output port 49 in the control circuit 20 to the left and right feed motor 14 via the drive circuit 18. A control signal for moving the heads 1A, 1B to the right is output, and then the process returns to step 202 to repeat the above-described process.

On the other hand, if it is determined in step 214 that all measurements of the workpieces to be measured have been completed, then in step 216 measurement is performed from the digital output port 49 of the control circuit 20 to the left and right feed motor 14 via the drive circuit 18. Heads 1A and 1B are shown in the diagram.
A control signal for moving it leftward to its original position is output, and the execution of the main routine ends.

Next, FIG. 8 shows the contents of the interrupt routine activated by the output of the latch circuit 105. In the figure, when the interrupt routine is started, step 3
At step 00, image data regarding the inner circumferential surface 81 of the object to be measured 80 is taken in from the image sensor 5 in the measurement heads 1A, 1B, and at the next step 302, the image data at each pixel in the image sensor 5 is stored in the frame memories 42A, 42B. It is stored in a predetermined memory area. That is, the image captured by the image sensor 5 has a donut shape as shown by the symbol Q in FIG. 9, and the position of each pixel forming this image Q is expressed by polar coordinates.
By converting this into orthogonal coordinates, the image data is stored in a predetermined memory area corresponding to each pixel of the image sensor 5 (FIG. 10). Here, in the image Q shown in FIG. 9, the radial direction indicates the depth direction of the object to be measured, and the circumferential direction indicates an image in the circumferential direction on the inner circumferential surface 81 of the object to be measured 80. In the next step 304, the frame memory 42
A defect site on the inner peripheral surface 81 of the object to be measured (referred to as a work) 80 is inspected based on the image data stored in A and 42B. That is, the image data stored in each address of the frame memories 42A, 42B and the ROM in the microcomputer 44 are stored in advance in the frame memories 42A, 4.
It is compared with reference data indicating a reference value of the amount of received light stored corresponding to each address of 2B. Furthermore, in step 306, it is determined whether there is a defect or not based on the comparison result in step 304. If it is determined in step 306 that there is no defect, then in step 308 the digital output port 48 is
A display signal is output to the display unit 21 to indicate that the corresponding workpiece is an acceptable product.

On the other hand, if it is determined in step 306 that there is a defect, the process moves to step 310. Step 3
In steps 10 to 314, reference value data indicating the reference value of the amount of received light is also stored for the image data stored in addresses adjacent to each address in the frame memories 42A and 42B in which the image data determined to be defective in step 306 is stored. are compared,
The presence or absence of defects and the presence or absence of adhesion of dust, etc., are determined. In step 314, the inner peripheral surface 8 of the workpiece 80 is
If it is determined that there is a flaw or a blowhole in the hole 1, a display signal is output from the digital output port 48 in the control circuit 20 to the display unit 21 in step 316 to display an image of the location where the flaw or blowhole has occurred. Execution of the import routine ends. If it is determined in step 314 that there is dust or dirt on the inner circumferential surface of the workpiece 80, a display signal is similarly output from the digital output port 48 to the display unit 21 in step 318, and the interrupt routine is executed. finish. Here the display unit 21
An image as shown in FIG. 11 is displayed. That is, as shown in the figure, the surface to be measured (inner circumferential surface) 81 of the workpiece 80 is depicted as a donut-shaped image 90, and areas where defects such as scratches or blowholes have occurred are marked with red circles and dust etc. Places where it is attached are marked with a blue Δ mark. Here, the circumferential direction of the donut-shaped image 90 is the inner peripheral surface 81 of the workpiece 80.
The radial direction corresponds to the depth direction of the workpiece 80.

If it is determined in step 314 that the workpiece 80 to be measured is an acceptable product, step 3
08, the display unit 21 displays that the product has passed the test, and the execution of the interrupt routine ends.

As explained above, in this embodiment, analog processing is used to determine the presence or absence of defects such as scratches on the inner peripheral surface of the object to be measured, and then an interrupt program is activated by a determination signal indicating the presence or absence of a defect, and the type of defect is determined. Since the structure is configured to display judgments such as the following, surface defects on the object to be measured can be measured at high speed, and the measurement time can be shortened compared to the conventional method.

[Effect of idea]

According to the present invention, it is possible to shorten the time required to measure surface defects on an object to be measured.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a surface defect measuring device according to the present invention, FIG. 2 is a block diagram of measurement heads 1A and 1B in FIG. 1, and FIG. 4 is a block diagram showing the specific configuration of the control circuit 20, FIG. 5 is a block diagram showing the specific configuration of the processing circuit 60 in the control circuit 20, and FIG. 6 is the control circuit 20. Timing charts for explaining the operation of the circuit 20, FIGS. 7 and 8 show the contents of the program executed by the microcomputer 44, FIG. 7 shows the contents of the main routine, and FIG. 8 shows the contents of the interrupt routine. A flowchart showing the contents, FIG. 9 is an image Q taken by the image sensor 5.
FIG. 10 is a diagram showing the positional relationship of each pixel sharing the image sensor 5 shown in FIG. 9, and FIG. The figure shows an image displayed on the screen of the display unit 21 when the inner peripheral surface 81 of the workpiece 80 has a defect such as a blow hole or a scratch, or when dust or the like has adhered thereto. 1A, 1B...Measuring head, 20...Control circuit, 2
1...Display unit, 60...Processing circuit.

Claims (1)

[Scope of utility model registration request] Two integrally installed measuring heads that photoelectrically convert the reflected light of the light irradiated onto the inner peripheral surfaces of two adjacent objects to be measured and output analog voltages corresponding to each detection area, and these two measuring heads. A driving means for moving the measuring head along the inner circumferential surface of each object to be measured and the detection outputs of the two measuring heads are taken in, the difference between these detection outputs is determined, and the difference and a preset reference voltage are calculated. and a control circuit that determines whether there is a defect on the inner peripheral surface of the object to be measured based on the comparison result, and outputs a control signal to the drive means for moving the measurement head to a predetermined position during measurement. A surface defect measuring device comprising: