JPS62247202A - Measuring method of relative height of body surface and apparatus therefor - Google Patents

Abstract

PURPOSE:To enable non-contacting measurement of a relative height between different points of measurement on a body surface, by differentiating an image signal available from a TV-camera and comparing it with a specified threshold level. CONSTITUTION:An image signal picked up by a TV-camera from a measured point is differentiated by a differentiating circuit 22 and an element of high frequency only is taken out and binarized pulses of white level or black level are obtained by comparing the output of the circuit 22 with the specified threshold level and consequently, the number of binarized pulses of the image signal of the measured points takes a maximum value when a focus of a lens coincides with the measured point. Consequently, calculation is made covering a field 1 or 1 frame on the binarized value of the specified inspection range including the measured point per displacement of a single distance of the lens as above relative to a body and the distance of displacement from the reference position of the lens at the time when the measured value reached the maximum value is obtained. And, a relative height (A height of one measured point relative to the other one) between different measuring points is obtained by calculating respectively a position of a measuring point relative to the reference point and difference of both points.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for measuring the relative height between different measurement points on the surface of an object and an apparatus for implementing this method. be.

[Prior art] In product inspection on a factory production line, etc., the height of unevenness formed on the surface of an object, the depth of a groove formed on the surface of an object, the slope of the surface of an object, etc. are measured. It is often necessary. Both of these measurements measure the relative height between different measurement points on the surface of an object (the height of one measurement point relative to the other measurement point).
It comes down to this.

As a method for automatically measuring the relative height between two points on the surface of an object, a method using a stylus to detect irregularities on the surface of the object has been proposed. In this method, the touch tip is moved from a reference position set above the surface of the object toward each measurement point on the surface of the object, and the distance traveled until the melt layer contacts the measurement point is measured 11 times. The relative height between different measurement points was calculated from the distance traveled.

[Problems to be Solved by the Invention] The above-mentioned 81 method requires the stylus to come into contact with the surface of the object, so it cannot be applied to objects that may be damaged by contact with the stylus. could not. In addition, there is a risk that the stylus may rupture if it comes into contact with an object, making it unreliable, so it cannot be used in cases where repeated measurements are required, such as in automatic online product inspection cages. It was difficult. In particular, when measuring the depth of a groove with a very small opening area, it is necessary to use a step with a very small diameter, which makes the contact piece very easy to break, making it impractical.

An object of the present invention is to provide a method for measuring the relative height of an object surface, which enables non-contact measurement of the relative height between different measurement points on the surface of an object, and an apparatus for implementing this method. There is a particular thing.

[Means for Solving the Problems] The first invention of the present application is a method for non-contact measuring the relative height between different measurement points on the surface of an object, and the method of the present invention , the lens of a television camera equipped with a microscope lens is directed at each measurement point on the object, and the position where the lens focuses on each measurement point is set as the focus position for the bin i.
・Moving a stationary lens at a certain distance including the position relative to the object, differentiating the video signal obtained from the television camera, and comparing the differential value with a predetermined threshold level. White level or black level 2
Obtain the value pulse. Then, each time the lens moves a unit distance with respect to the object, the 2Vi conversion pulse of the video signal of a predetermined inspection area including the measurement point is processed over one field or one frame, and the maximum value of the counted value of the pulse is calculated. The distance of the focus position from the reference position is determined by determining the position of the lens relative to the object when the value is obtained as the focus position. The relative height between the different measurement points is determined by calculating the difference in distance 11JI from the reference position between the focus position determined for each of the different measurement points in this way.

A second invention of the present application is a measuring device for carrying out the method of the first invention, and an embodiment of the device of the second invention is shown in FIGS. 1 and 2. , the television camera 9 and the lens are moved relative to the object L
' moving mechanism 15, differentiating circuit 22, 211i conversion circuit 23, measurement command signal generation circuit 20, measurement command signal counter 30, pulse counter 29, storage means 31, calculation c1 means 33, It is crystallizing.

The television camera 9 is equipped with a microscope lens 8 which is directed towards the object 2 . Movement is horizontal 15 is lens 8
The lens is moved in the direction of the optical axis relative to the object with the position of the optical axis coincident with each measurement point pi, p2 of the object 2. The differentiating circuit 22 connects the television camera 9 to 1! at each measurement point. Differentiate the video signal ■a given by '7,
The binarization circuit 23 compares the output of the differentiating circuit with a predetermined threshold level Vt, and generates a pulse VWp- every time the output of the differentiating circuit exceeds the threshold level. The measurement command No. 8 generation circuit 20 generates a measurement command signal every time the lens moves to the object by 111 distance tldZ at each measurement point, and the measurement command signal counter 30 receives this measurement command signal. Multiply Mt by 21. The pulse counter 29 counts the number of binary pulses of the video signal of a predetermined inspection area including 10 to 1111 fixed points where the measurement command signal Mt is generated over one field or one frame, and the storage means counts the number of words for each measurement point. The count value of the pulse counter 29 is stored together with the argument ze1 of the measurement command signal multimeter 30. The performance means 33 converts the count value of the measurement command signal counter corresponding to the 1d maximum value of the count value of the pulse counter stored in the storage means 31 into the fit rl! which indicates the focus position. The relative height between the different measurement points is calculated from the unit distance and the difference of one or more fields indicating the focus position at the measurement point as 1ifT.

[Operation of the invention] As the lens focuses, the image of the irregularities on the surface of an object becomes a sharp image with strong contrast, and the components with high spatial frequencies increase, and when the lens is in focus, the components with high spatial frequencies become the most abundant. .

Therefore, as mentioned above, the video signal obtained by m-images of the measurement point with a television camera is differentiated by a differentiating circuit to extract only high frequency components, and the output of the differentiating circuit is compared with a predetermined threshold level. When the white level or black level binary pulses are obtained, the number of binary pulses of the video signal at the measurement point is maximized when the lens is focused on the measurement point. Therefore, as described above, each time the lens moves a unit distance with respect to the object, the binarized pulses of the video signal in a predetermined inspection area including the measurement point are counted over one field or one frame, and the counted value is By determining the moving distance of the lens from the reference position when the maximum value is reached, the position t relative to the tv position of each measurement point on the object surface can be determined. Therefore, by using this method to find the positions of different measurement points relative to the reference position and calculating the difference between the two, the relative height between the different measurement points (the height of one measurement point relative to the other measurement point) can be calculated. be able to.

As described above, according to the present invention, the relative height between different measurement points on the surface of an object can be measured in a non-contact manner without using the touch 21. It is possible to measure the depth of irregularities and grooves.Also, since the measurement point is magnified with a microscope lens, it is possible to measure minute grooves and irregularities.Furthermore, since no stylus is used, Since there is no damage or leakage, and the reliability is high, it can be used for online product inspection without any problems.

[Example 1 The present invention will be described in detail below with reference to the accompanying drawings.

FIGS. 1 and 2 show an actual apparatus for carrying out the method of the present invention.
In Fig. 1, 1 is an X-Y table that supports the object to be measured, and in this example, the object to be measured is a crystal of a pull-top can (hereinafter referred to as the object to be measured). call.

) 2 is placed on the X-Y table 1.

'F12 of the pull-top can container is a disc-shaped panel part 2
00, an annular rib 201 formed by deforming the outer peripheral part of this panel part 200 so as to be recessed inside the can over the entire circumference, and a curled part 202 formed on the outside of this rib. , a rivet part 203 formed by pushing the center part of the panel part 200 outward, and a knob part 204 fixed to the panel part 200 by the rivet part 203 . A groove 206 of a predetermined shape is formed in the panel part 200, and by raising and pulling the knob part 204, the inner part of the groove 206 can be cut off to form an opening in the lid. The lid 2 is attached to the can body by fitting the periphery of the opening of the can body inside the curled portion 202 and curling the entire circumference of the curled portion 202.

” In the above 42, the groove 206 is shown in an enlarged view as shown in FIG.
- If hl is shallower than the specified depth, and the thickness hl at the bottom of the groove is thicker than the specified value, the inner part of the groove 206 cannot be cut by the knob 204,
2-hl is deeper than specified, tM206 bottom thickness hl
If it becomes thinner than specified, the lid 2 will not be able to withstand the internal pressure of the canister, which is dangerous. Therefore, for each two pull-top can containers, the depth h2-
It is necessary to strictly manage hl, but conventionally it was less than 206
Since there was no suitable method to automatically measure the depth of l! The lids 2 were removed from the manufacturing line at a constant rate, and the depth of 206 times was measured using the above-mentioned side-to-side method.

The method of the present invention makes it possible to perform such measurements automatically and without contact. When measuring the depth of the above tM 206 by the method of the present invention, measurement points P1 and P2 are set on the bottom surface of the tivi 206 and the surface of the portion outside the groove 206, respectively, as shown in FIG. The relative height between measurement points P1 and 220 of measurement point P
Measure the height of measurement point P2 = h2-411).

A movable frame 3 is arranged above the X-Y table 1 on which M2 as the object to be measured is placed.
is supported by a fixed frame (not shown) so that it can move only in the vertical direction. A female threaded portion extending in the vertical direction is provided at one end of the movable frame 3, and a threaded rod 4 is screwed into this female threaded portion. The threaded rod 4 is connected to a pulse motor 6 via a gear transmission mechanism 5. The pulse motor 6 is supplied with a pulse voltage V of a constant frequency from a pulse power source 7.
p is given, and each time the pulse power supply 7 generates a pulse voltage, the pulse motor 6 is driven and the threaded rod 4 rotates by a minute angle, thereby moving the movable frame 3 a predetermined minute distance in the vertical direction. It is designed to be displaced gradually.

A television camera 9 equipped with a microscope lens 8 is attached to the movable frame 3, and the lens 8 of this television camera has its optical axis aligned with the panel section 2 of the lid (object to be measured) 2.
It is oriented toward the lid 2 in a state perpendicular to the surface of the 00.

The lens 8 is arranged so that when the distance between its tip and the subject is equal to the set value fO, a focused image of the measurement point on the surface of the object to be measured is formed on the light-receiving surface of the television camera. 1- is adjusted).

A half mirror 10 is arranged between the lens 8 and the light receiving surface of the television camera 9, and a lamp housing 11 is arranged at the other end of the movable frame 3. A lamp 12 and a condensing lens system 13 are disposed within the lamp housing 11, and a parallel beam of light is irradiated from the lamp 12 to the half mirror 10 through the lens system 13. A known epi-illumination device is configured by the light source 11 and the half mirror 10,
Light r! The light emitted from the half mirror 10 is reflected toward the lens 8 and travels parallel to the optical axis of the lens 8 toward the object to be measured 2. This light passes through the lens 8 and is irradiated onto the surface of the object to be measured 2 as epi-illumination light LS. This light is reflected by the surface of the object to be measured, and the reflected light 1r reaches the light receiving surface of the television camera 9 through the lens 8 and the half mirror 10.

In this embodiment, the threaded rod 4, the gear transmission mechanism 5, and the pulse motor 6 constitute a movement example 15 for moving the lens 8 together with the deviation camera in a direction parallel to the optical axis of the lens. This moving mechanism 15 moves the lens 8 to the surface of the object 2 to be measured in a certain distance Zo (see FIG.
is moved together with the television camera 9. In FIG. 3, 01 and Q2 are the set pressures ll! from measurement points P1 and P2, respectively. When the lens 8 carries an image of the measurement point P1, the measurement point P1 is in focus when the lens 8 is at the focus position Q1, and when the lens 8 carries an image of the measurement point P2. When the lens 8 is at the focus position Q2, the measurement point P2 is in focus. In this embodiment, the lens 8 is set at the focus position fffi.
Q2J: A position further away by a certain distance is defined as the upper limit position UL, and a position further closer to the measured object 2 than the focus position Q1, which is closer to the measured object 2, is defined as the lower limit position LL. Then, the lens 8 is moved from the lower limit position LL to the upper limit position LJ for each measurement point.
After moving the lens 8 to the upper limit position by intermittently moving a certain distance ZO to I- by a unit distance l1ltdZ, the pulse is reversed and the tip of the lens 8 is moved to the lower limit. Avoid returning to position LL.

The L2 moving mechanism 15 is equipped with a lower limit position detection means such as a limit switch and an upper limit position detection signal for detecting that the lens 8 is located at the lower limit position LL and the upper limit position U, respectively. The detection means outputs a lower limit position detection signal N and an upper limit position detection signal NU when the lens 8 reaches the lower limit position LL and the upper limit position tJL, respectively.

The X-Y table 1 holds the object 2 to be measured.
The motor moves the X and Y directions perpendicular to each other on the horizontal plane.
The lens 8 has a known structure in which the measurement points P1 and P2 of the object to be measured 2 are sequentially moved during measurement.
The object to be measured 2 is moved on a horizontal plane so as to match the position of the optical axis.

The X-Y table 1 is provided with a detection means for detecting the completion of positioning of the object to be measured, and this detection means detects the completion of positioning of the object to be measured. When the operation is completed, positioning completion signals Npt and Np2 are output.

The output of the pulse power source 7 is supplied to the pulse motor 6 and 5, and is also supplied to the measurement command signal generation circuit 20. This measurement command signal generation circuit 20 consists of a preset counter, and a pulse power source 7 moves the lens 8 by a unit distance #ldZ.
The measurement command signal Mt is output every time the number of pulses required to avoid the movement is output.

The video signal Va output from the television camera 9 is input to the signal processing device 21 together with the measurement command signal Mt. This signal processing device 21 processes the video signal using the measurement command signal Mt as a processing start signal, and outputs a signal processing end signal MS when the processing is completed.

A control station 16 is provided for controlling the X-Y table 1 and the moving section 15. This a, 1Jtll device consists of a microcomputer, and a measurement start signal M
i, a measurement command signal Mt, a signal processing end signal MS,
The pulse power source 7 is controlled to operate the moving mechanism 15 in a predetermined sequence by inputting the positioning completion signals N1)1 and Np2, the lower limit position detection signal N (and the lower limit position detection signal N11).

The measurement start signal Mi is given, for example, when it is determined that the object to be measured has been carried onto the X-Y table 1 at Tl12.

When this measurement start signal Mi is given, the control device 16
- Give a positioning command signal to the Y table 1 to first perform a positioning operation to align the measurement point P1 with the optical axis of the lens 8. When this positioning operation is completed and a positioning completion signal Np1 is given from the X-Y table 1 side, the υ control device 16 gives a command to the pulse power source 7 to output a pulse for lowering the lens 8. This drives the pulse motor 6, and when the lens 8 reaches the lower limit 1iffLL, the lower limit position detection means provided in the moving mechanism 15 outputs the lower limit position detection signal DN1. When this lower limit position detection signal N[ is output, the control device 16G stops the output of pulses from the pulse power supply 7U, and then the pulse power supply 7
The number of pulses required to move the lens 8 upward by an intermediate distance is outputted. When the number of pulses necessary to avoid moving the lens 8 by a unit distance is output, the measurement command signal generation circuit 20 outputs the measurement command signal Mt. The signal processing device 21 starts processing the video signal when the measurement command signal Mt is output, and outputs a signal processing end signal Ms when the signal processing is completed. When this signal processing end signal Ms is output, the control device 16 gives a command to the pulse power source 7 to generate the necessary number of pulses to move the lens 8 a unit distance dZ again. The control I device 16 repeats the same operation thereafter, and the signal processing device 21 controls the lens 8.
Processes the video signal ``a'' every time 1t1dl moves fIJ outside the unit. When the lens 8 reaches the lower limit position tJL, the upper limit position detection means outputs the lower limit position detection signal NU. When this upper limit position detection signal N11 is output, the controller 11G gives a command to the XY table 1 to perform a positioning operation to align the measurement point P2 with the optical axis of the lens 8. When this positioning operation is completed, the positioning completion signal N
1) When 2 is output, the control device 16 gives a command to the pulse power source 7 to avoid outputting a pulse for lowering the lens 8. When the lens 8 reaches the lower limit 11'/ii'i l-l- and the lower limit position detection signal NL is generated, the control '
The 2II unit 1G stops the pulse output from the pulse power source 7, and then gives a command to the pulse power source 7 to output a pulse to set the lens 8 at F'/1. From then on, the control device repeats the same operation as the +h operation performed for the measurement point P1, and sends the signal to the processing device 13 to process the signal every time the lens 8 increases by J=+f1J by -1 outside the unit. When the lens 8 reaches the upper limit position UL, the limit (91 position detection signal bow N)
When U emits 1, the control device measures it! It outputs a signal indicating that the FJJ work is completed, and outputs a command signal instructing to carry out the object 2 to be measured from the X-Y table 1.

In the above explanation, when the lens 8 reaches the lower limit position LL and the upper limit IQ position UL, the upper limit (lower position detection signal N
5 detection means are provided to generate U and lower limit position detection signals @NL, and these position detection signals are used to detect the lower limit position and lower limit position of the lens 8. Once the object is determined, the total moving distance of the lens 8 111I [Z o and () 1st position yi moving distance dZ are constant, so it can be calculated by the four numerical values of the output pulse of the pulse power source 7 without using the detection signals NL and NU. It is also possible to perform control operations by detecting the position of the lens 8.

Next, the configuration and processing contents of the signal processing device 21 will be explained with reference to FIG. In FIG. 2, 22 is a differentiation circuit that differentiates the video signal Va, 23 is a binarization circuit that compares the output of the differentiation circuit 22 with a predetermined threshold level and converts it into a binary value, and 24 is a horizontal synchronization circuit from the video signal Va. This is a synchronization separation circuit that separates the signal VSh and the vertical synchronization signal Vsv. 25 is a vertical inspection area setting circuit which sets a vertical inspection area by inputting the vertical synchronization signal Vsv; 26 is a horizontal inspection area setting circuit which sets a horizontal inspection area by inputting the horizontal synchronization signal Sh; 27 is vertical 11th signal 7=,
This is an inspection field setting circuit that sets an inspection field by inputting V SV and measurement command signal Mt, and includes a vertical inspection area setting circuit 25, a horizontal inspection area II! ! Outputs VQ1. of setting circuit 26 and test field setting circuit 27;
Both VQ2 and V' are the binary pulses Wp output by the binary circuit 23 and input to the AND circuit 28.
A pulse Vwp'' is output every time a numeric pulse Vwp is generated and the AND is established.

This pulse Vwp- is input to the pulse generator 29 and counted. Also, the measurement command signal Mt is the measurement command signal ￥'
331 number is input to m30 and is numbered. At the fall of the output Vf of the inspection field setting circuit 27, F[l! A reading command is given to the memory means 31, and the memory means 31 reads the 91 value m of the crystal 1 numeral 29 and the count value ``) of the h numeral 30 when this instruction)h command is given, and performs one test. Store as data for one field.

♂1 Counter 29 [It is reset at the rising edge of the measurement command signal Mt, and g1 defeat 30 is, for example, when the lens 8 is at the upper limit FI.
It is reset by the upper limit l detection signal NU that detects that UL has been reached. Reference numeral 32 denotes an it-number processing end signal generation circuit, and this circuit performs Mq determination a predetermined number of times and outputs a signal to the counter 30.
When the count value reaches the set value, a trust processing end signal Ms is output.

Further, 33 is a calculation means (ζ), which is a storage means 3.
The 81 value of the measurement command signal numerator 30 of 1 is stored in bin 1~
() at measurement points P1 and P2 as a count value indicating the position.
The relative height between the measurement points Pi and P2 is determined from the difference in the ai number 1, which indicates the focus position, and the median distance dZ.

The test field setting circuit 27 is composed of flip knob circuits Fl to FF3 and a differentiator circuit, for example, as shown in FIG. The signal waveforms of each part of this circuit are shown in Figure 5 (a
> or f), when the measurement command signal Mt is given, the 7-trip circuit FF is activated at the rising edge.
1 is set, and the output Vfl of the flip-flop circuit FF1 rises at the rise of the measurement command (CiQMt).
If the vertical synchronizing signal VSV is applied while the output Vf1 of 1 is being held at tj, a pit is generated. -C Vertical synchronization signal V generated first after measurement command signal Mt is given
When Sv rises, the output of flip-flop circuit FF2 is
[ stands up. In addition, the flip-flop circuit FF3 outputs the vertical synchronizing signal VSV in a state where the output Vf of the flip-flop circuit FF2 is maintained at 1j! When you receive it, you will be asked to retweet it. Therefore, the output of the flip-flop circuit [[:3 ■[
3 is the measurement command (, E, and tj is received. 1 (9. rises when the second vertical synchronizing signal ysv is given.The output of this flip-flop circuit "F3" is differentiated by the differentiation circuit MD, The output pulse VdO of this differential circuit resets the flip-flop circuit [[1~[2E3]]. Therefore, the measurement command signal T3.M is sent to the output side of the flip-flop circuit FF2 for the first time. A rectangular wave-like test field setting signal V' is obtained that lasts from the vertical synchronizing signal vSvl/) to the vertical rising edge of the generated vertical synchronizing signal \lSV. In this example, one field immediately after the measurement command signal M1 is applied at J'3 at each measurement position (the position where the lens 8 is stopped) is set as an inspection field, and C measurement is performed in this inspection field.

Next, the vertical inspection area setting circuit 25 includes a sawtooth wave I5I generation circuit 32 and a comparison circuit CP1, as shown in FIG.
and CR2, an inverter IN, and an AND circuit A1. The operating waveforms of each part of the vertical inspection area setting circuit 25 are as shown in FIGS.
The sawtooth wave signal generating circuit 32 outputs a sawtooth wave signal 3t which rises at a constant slope from the rising edge of the vertical synchronizing signal VSV every time it is applied, and returns at the rising edge of the next vertical synchronizing signal. The comparison circuit CP1 converts the sawtooth wave signal St into a variable resistor P! The output signal VC1 whose logic state is "1" during the period in which the sawtooth wave signal 3t is equal to or higher than the threshold level voltage ■t1 compared to the threshold level voltage v obtained at both ends of iR1 (see FIG. 7). C) is output. Furthermore, the comparator circuit CP2 compares the sawtooth wave signal O8t with the threshold level voltage Vt2 obtained across the variable resistor R2, and compares the sawtooth wave signal St with the threshold level voltage Vt2. Output signal whose logic state is “1” “;”JV
C2 (C in FIG. 7) is output. Impark IN inverts this signal VC2 and outputs signal c2 (C in Figure 7),
The AND circuit A1 outputs the vertical direction check pirate setting signal bow VQI (FIG. 7f) whose logic state is "1" while the logic states of the signals VC1 and C2 are "1" at the same time.

This vertical one-direction inspection area setting signal V01 rises at a certain time delay from the generation time of %M+ synchronization signal Vsv and falls before the time when the next vertical synchronization signal VSV rises (no. , the signal width of this signal Vql is 1
This corresponds to the width in the direction of the center of gravity of the area to be inspected (inspection area) within the screen of the field. The width of this signal Vql (vertical inspection area III) can be appropriately adjusted within the range of one field by changing the threshold cold level v[1 and Vt2.

The horizontal inspection area setting circuit 26 is constructed in the same manner as the central inspection area setting circuit 25 shown in FIG. Horizontal direction inspection area where the synchronization signal Sh is input, rises after a fixed time ν from the generation time of the horizontal synchronization signal VSV, and falls at a fixed time before the rise of the next horizontal synchronization signal ysh A setting signal Vq2 is output.This horizontal direction inspection area 1Illi setting signal Vq
The signal width of 2 corresponds to the horizontal width of the inspection area of 1 within the screen of 1 field.

In this embodiment, the vertical inspection area setting signal Vql
Only the signals that fall within the inspection area defined by the horizontal inspection area setting signal Vq2 are processed! I! Signals outside this inspection area are excluded from processing.

By setting the inspection area in this way, noise can be removed and the vJ degree of measurement can be improved.

Next, referring to Fig. 8 and Fig. 9, each measurement point Pl and P
The measurement operation performed for 2 will be explained.

As shown in FIG. 8(a), when the pulse source 7 generates an intermediate number of pulses (4 in this example), the measurement command signal generation circuit 20 changes as shown in FIG. 8(b). Indicated by J: Outputs the measurement command signal Mt. When this measurement command signal Mt is generated, the inspection field setting circuit 27 outputs the measurement command signal Mt.
The test field setting signal Vf (FIG. 8 d and FIG. 9 g) that lasts from the rising edge of the vertical synchronizing signal VSV (FIG. 8 C) generated directly after the occurrence of the vertical synchronizing signal VSV until the next rising edge of the vertical synchronizing signal VSV. Output Jro. As shown in FIG. 8<e> and FIG. 9(b), the vertical inspection area setting circuit 25j outputs the Φ white direction inspection area setting signal VQ1 having a predetermined width, and generates the horizontal inspection area setting signal. The circuit 26 outputs a horizontal inspection area setting signal VQ2 (FIG. 9r) having a predetermined width every time horizontal synchronous transfer>3ysh occurs.

The video signal va has a waveform C1 as shown in FIG. 9(C), for example. This video signal is differentiated by a differentiating circuit 22. The output signal V a 'f;L of the differentiating circuit 22 is as shown in FIG. 9(d), and this signal ya- is compared with the threshold level Vt by the binarization circuit 23. Binarization circuit 23
At 11.1, when the output signal j3Va- of the differentiating circuit 22 becomes equal to or higher than the threshold level yt, as shown in FIG. output pulse (VWI).

The AND circuit 28 generates a binary pulse v when the inspection two-yield setting signal Vr, the double-direction inspection area setting signal VQ1, and the horizontal inspection area setting value VO2 are generated simultaneously.
Every time Wp occurs, an AND is established and a pulse Vwp- is output as shown in FIG. 9(h). pulse v wp
' is incremented by 41 by the counter 29. The counter 30 counts the measurement command signal Mt by one. Count! W30 number #
in corresponds to each measurement position (stop position of lens 8), and when this h1 loss 1in is multiplied by the unit movement distance dz, the movement distance from the lower limit position to each measurement position #[L (=n
XdZ) is obtained. A reading command is given to the storage means 31 at the falling edge of the test field setting signal @Vf, and when this reading command is given, the storage means 31 reads and stores the counts of the counters 29 and 30 at that time.

After a predetermined number of measurements are made for each measurement point, the counter 30
When the i1 value reaches a predetermined value (at this time, the lens 8 reaches the lower limit position UL), the signal processing end signal generation circuit 32
outputs a measurement signal processing end signal MS.

The data measured at each of the measurement points P1 and P2 as described above and stored in the storage means 31 are plotted on the horizontal axis with the moving distance MZ of the lens 8, and on the vertical axis at each measurement position.
When the count value m of the binarized pulse of 3 GJ is taken and shown, the measurement point P1 is as shown in FIG. 10, and the measurement point P2 is as shown in FIG. 11, for example. Furthermore, the first
The value 7 on the horizontal axis in FIGS. 0 and 11 was obtained by multiplying each crystal 1a value of the counter 30 at each measurement position by the distance dZ of movement of the lens.

The image of unevenness on the surface of an object becomes a sharp image with a strong 1-1-1-last as the lens focuses, and the components with high spatial frequencies increase, and when the lens is in focus, the components with high spatial frequencies become the most abundant. Therefore, as described above, each measuring point is imaged by JIi2 using the TV digital camera 9, and the 1-watt video signal is differentiated by the differentiating circuit 22 to extract only high frequency components, and the output of this differentiating circuit is set to a predetermined threshold. Compared to level Vt, the white level or black level binary pulse is 1! ? Then, the number of binarized pulses of the video signal at the measuring point becomes maximum at (2) when the lens focuses on the measuring point. That is, for the measurement point P1, the position 71 in FIG. 10 is the focused position of the lens, and for the measurement point P2, the position 72 in FIG. 11 is the focused position of the lens 8. Therefore, in this example, when the difference (Z2-Zl) between Z2 and Zl is taken by the cotton drawing means 33, this difference will increase the height of the groove 2 at the measuring point P2 with respect to the measuring point P1.
06 depth).

As described above, in the present invention, the relative height of the surface of the object to be measured can be automatically measured simply by processing the video signal obtained from the television camera without contacting the object to be measured. can be applied to online product inspection.

In the above example, the number of binarized pulses set in one field is counted, but if interlaced scanning is performed with a television camera, the inspection area will be counted over one frame. It is also possible to convert the binarized pulses into SI numbers.

In the above description, the depth of the grooves on the surface of the object to be measured is measured, but the method of the present invention can also measure the height of the irregularities on the surface of the object to be measured, the slope of the surface, etc.

The method GEL of the present invention, which can be widely applied in measuring the relative height between different measurement points [1 and 22] on the surface of the measured object of interest, can be used to determine the relative height of different It is preferable that the materials of measurement points P1 and P2 are the same as 1G.

[Effects of the Invention 1] According to the present invention, the relative heights of different measurement points on the surface of an object can be measured in a non-contact manner without using any force. It is possible to measure irregularities on the surface of an object, the depth of grooves, etc. without damaging the surface of the object. Furthermore, since the measurement point is magnified using a microscope lens, even minute grooves and irregularities can be measured. Furthermore, since no melt layer is used, there is no risk of breakage, and the reliability is high, so there is an advantage that it can be used for online product inspection etc. without any problems.

[Brief explanation of drawings]

Fig. 1 is a block diagram schematically showing the overall structure of an embodiment of the present invention, Fig. 2 is a block diagram showing an example of the structure of a signal processing circuit used in the embodiment, and Fig. 3 is an object to be measured. FIG. 4 is a block diagram showing an example of the configuration of the inspection field setting circuit used in this embodiment, and FIG.
6 is a block diagram showing a configuration example of the vertical direction inspection area used in the same embodiment, 1 setting circuit, FIG. 7 is a signal waveform diagram of each part in FIG. 6, 8 and 9 are waveform diagrams showing the operation waveforms of each part of the same embodiment, and FIG.
The figure and FIG. 11 are graphs showing measurement data at different measurement points in the same example. DESCRIPTION OF SYMBOLS 1... X-Y table, 2... Object to be measured (can lid), 3... Rotation frame, 4... Threaded rod, 5...
...Gear transmission mechanism, 7.Pulse power source, 8.Microscope lens, 9.TV camera, 10.Half mirror 115.VJ41 structure, 20.Measurement command signal generation. Circuit, 21... Faith processing device, 22...
- Differentiation circuit, 23... Binarization circuit, 24... Synchronization separation circuit, 25... Vertical i-direction inspection area setting circuit, 26.
...Horizontal inspection area iii! Setting circuit, 27... Inspection field setting circuit, 28... AND circuit, 29...
・Counter, 30... Recording device, 31... Storage means, 3
2... Performance C) Means. (1 other person) -゛Figure 4Figure 6Figure 7Figure 10Figure 11　　　〇〇〇 151] 1) Akira 1 Director General Kuroguchi 1 Akio Tono 1,
'1jfl Display 1) Application No. 61-73822 2, Title of the invention ZJ method and apparatus for measuring the relative height of the surface of an object 3, Name for correction Relationship with 11 cases Patent applicant 1-1 Tree J1 Sakuko Kogyo Co., Ltd. (37G) Toyo Seikan Co., Ltd. I 4, Agent Tokyo W ru Ward Shinkaku 4-31-6 Bun III Hill 6 Fl'i5, Subject of amendment light lit;! f “Detailed Description of the Invention” (1116
, content of correction

Claims (2)

[Claims] (1) In a method of measuring the relative height between different measurement points on the surface of an object, a lens of a television camera equipped with a microscope lens is directed at each measurement point of the object, and the lens is attached to each measurement point. The lens is moved relative to the object in a certain distance section including the focus position, and the video signal obtained from the television camera is differentiated, and the differential value is set to a predetermined value. A binary pulse of the white level or black level is obtained by comparing it with a threshold level, and each time the lens moves a unit distance with respect to the object, the binary value of the video signal of a predetermined inspection area including the measurement point is obtained. 1 field or 1
The position of the lens relative to the object when the maximum value of the count value of the pulse is obtained by counting over the frame is determined as the focus position, and the distance of the focus position from the reference position is determined, and the distance is determined for each different measurement point. A method for measuring the relative height of an object surface, characterized in that the relative height between different measurement points is determined by calculating the difference in the distance between the focused position and the reference position. (2) A device for measuring the relative height between different measurement points on the surface of an object, which includes a television camera that includes a microscope lens and the lens is directed toward the object, and the position of the optical axis of the lens. a moving mechanism that moves the lens in the direction of the optical axis relative to the object while being aligned with each measurement point of the object; and a movement mechanism that differentiates the video signal obtained from the television camera at each measurement point. A differentiating circuit that
a binarization circuit that compares the output of the differentiation circuit with a predetermined threshold level and generates a binarization pulse every time the output of the differentiation circuit exceeds the threshold level; and a binarization circuit that generates a binarization pulse each time the output of the differentiation circuit exceeds the threshold level; a measurement position instruction signal generation circuit that generates a measurement position instruction signal every time the object moves a unit distance with respect to the object; a measurement instruction signal counter that counts the number of measurement instruction signals; and a measurement instruction signal counter that generates the measurement instruction signal. a pulse counter that counts binarized pulses of a video signal in a predetermined inspection area including the measurement point over one field or one frame; a memory means for storing the count value of the command signal counter together with the count value of the pulse counter; and a counter indicating the focus position of the count value of the measurement command signal counter when the count value of the pulse counter stored in the memory means reaches a maximum. A relative height on the surface of an object, characterized in that it is equipped with a calculation means for calculating the relative height between the different measurement points from the difference in numerical value indicating the focus position at the different measurement points and the unit distance. Measuring device.