JPH0453257B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention uses an imaging device such as a television camera to photograph the entire inspection surface in order to detect surface defects such as cracks and corrosion existing on metal surfaces. The present invention relates to a device for automatically recording and editing only the image signal of an inspection surface where a defect exists on another recording means after recording it on a recording means such as a VTR.

(Prior Art) The applicant previously inspected the inner surface of a tube for abnormalities.
As shown in FIG. 2, a swinging arm 44 is provided at the front of the self-propelled vehicle 1 equipped with a traveling mechanism 10 and moving in a pipe so that it can swing back and forth, and an eddy current flaw detector is attached to the lower end of the swinging arm 44. 4, and while moving the self-propelled vehicle at a speed of approximately 4 m/min, swing the swinging arm back and forth at high speed,
proposed a device that scans and inspects the inner surface of tubes using the method (Japanese Unexamined Patent Publication No. 1983-26256).

The device can further be equipped with a television camera 5 at the front, which photographs the inspection area and transmits the inspection signal of the eddy current flaw detector 4 and the television camera 5.
The image signal is subjected to signal processing by the signal processing unit 6 mounted on the self-propelled vehicle 1, and then sent to the transmission cable 2.
It is sent to the monitor unit 3 via the pen recorder 83 and recorded on the VTR 81, and is also sent to the monitor TV 8.
2 directly monitors the condition of the inspection surface.

The transmission cable 2 has a power line, an optical fiber, and a reinforcing wire embedded in a table body made of elastic resin.

As shown in FIG. 3, the eddy current flaw detector 4 has a defect detection coil 41 with a small diameter and an excitation coil 40 with a larger diameter than the coil arranged concentrically.
It is fixed and integrated with 42.

The signal processing unit 6 supplies a high-frequency excitation current to the excitation coil 40, detects changes in impedance that occur in the detection coil 41 by scanning the inspection surface, and further performs phase detection on the detection signal to connect the flaw detector 4 and Lift-off signal Vx caused by variation in distance (lift-off) from inspection surface 9 and defect 9 on inspection surface 9
It outputs a flaw signal Vy caused by the presence of 1.

The lift-off signal V _x and the flaw signal V _y are recorded on the pen recorder 83 of the monitor section 3, thereby allowing defects on the inner surface of the tube to be discovered. The state of the defective inspection surface can be confirmed by playing back the magnetic tape recorded by the VTR 81 and comparing it with the chart of the pen recorder 83.

(Problem to be solved) In the above device, the TV camera 5 and the VTR
81 operates continuously during the scanning period, so the VTR
In 81, even normal inspection surfaces with no defects are recorded.

For example, when reporting test results to a test client, images of the entire test are often required, but in some cases, images of normal areas may not be necessary. Therefore, another VTR for editing is connected to the VTR 81, and only the image of the inspection surface where the defect exists is selected.
Editing and recording are done on a VTR.

However, in the editing work mentioned above, while checking the recording chart of the pen recorder 83 and the playback screen of the VTR 81, the VTR for editing is manually turned on.
I had to turn it off, which was a problem that took time and effort.

(Means for solving the problem) In order to solve the above problem, the present invention connects a second recording means for editing and recording to the first recording means that records all images of the inspection surface, The second recording means is automatically turned on and off.

The first recording means records an inspection signal, an image signal, and a position signal indicating the scanning position on the inspection surface, and the inspection signal obtained by reproducing the recording means is input to a signal processing circuit for inspection. This is converted into a defect signal indicating the presence of surface defects.

The second recording means can be controlled by an ON-OFF control signal, and the defect signal is input as the ON control signal.

(Function) When the inspection signal, image signal, and position signal obtained by scanning a normal inspection surface are being reproduced by the first recording means, a high-level defect signal is output from the signal processing circuit. This does not occur, and the second recording means remains in a stopped state without being driven.

When the inspection signal, image signal, and position signal obtained by scanning the defect location on the inspection surface are reproduced by the first recording means, the level of the defect signal from the signal processing circuit exceeds a predetermined value, and the level of the defect signal from the signal processing circuit exceeds a predetermined value. Go to 2. Recording method
ON control signal is sent.

As a result, the second recording means is driven, and the first recording means is driven.
Recording of the image signal and position signal input from the recording means is started.

After a certain period of time has passed since the defect signal was generated,
Alternatively, when the signal level drops below a predetermined value, the second recording means stops operating.

(Effects of the Invention) Since the second recording means records the image signal of only the defective location on the inspection surface, the defect state of the inspection surface can be quickly confirmed after the inspection is completed. Further, the position of the defect can be known from the position signal recorded together with the image of the inspection surface where the defect exists.

(Example) FIG. 2 is a schematic diagram of a pipe inner surface inspection device proposed by the applicant as described above, in which a self-propelled vehicle 1 is placed inside a cargo oil pipe 90 installed in an oil tanker and runs. Self-propelled vehicle 1 from monitor section 3 on deck 92
The inspection signal and the image signal are sent to the monitor section 3 for monitoring.

The self-propelled vehicle 1 is equipped with a running mechanism 10 consisting of an endless belt and a plurality of rollers on both sides, and a driving device (not shown) such as an electric motor or a pulse motor is connected to each running mechanism 1.
0, and the drive device is connected to the monitor section 3.
The movement of the self-propelled vehicle 1 can be switched to forward, stopped, backward, etc. under the control of a signal from the travel control section 7.

As described above, at the front of the self-propelled vehicle 1, there are the eddy current flaw detector 4 supported by the swinging arm 44, the television camera 5 for photographing the scanning range of the flaw detector 4, and the illumination light 50.
It is equipped with.

The eddy current flaw detector 4 is a mutual induction type probe shown in FIG. 3, but a self-induction type probe can also be used.

Furthermore, the self-propelled vehicle 1 is loaded with a signal processing section 6, which will be described later.

The transmission cable 2 has one end connected to the self-propelled vehicle 1,
The length of the drum 21 on the deck 92 that is fed out into the pipe is
Further, the drum 21 and the monitor section 3 are connected by a cord 20.

A cable guide 22 is fixed to the end of the tube 90 to guide the cable 2 fed out from the drum 21 into the tube.

The monitor unit 3 installed on the deck 92 superimposes numerical or character data such as inspection results on the image signals from the control unit 7 that controls the forward and backward movement and stopping of the self-propelled vehicle 1 and the television camera 5. Pause image synthesis circuit 70 and signal display recording device 8
It consists of The signal display and recording device 8 includes a data recorder 80 and a pen recorder 83 for recording test results, a monitor television 82 for displaying image signals captured by the television camera 5, and a first monitor for recording all image signals together with the test results. VTR81
It consists of

FIG. 4 is a block diagram of an electric circuit installed in the apparatus shown in FIG. 2, and each component of the block diagram will be described in detail below.

The signal processing unit 6 to which the output signal V ₀ from the eddy current flaw detector 4 is input is connected to the eddy current flaw detector 4 as shown in FIG.
an oscillator 60 that supplies a high-frequency excitation current to the excitation coil 40, a differential amplifier 63 that detects impedance changes of the detection coil 41 and outputs a test signal Vd, a pair of phase shifters 61 and 62, and a synchronous detector, respectively. 64 and 65.

When a high-frequency current is passed through the excitation coil 40 and the coil is brought close to the inspection surface 9, the high-frequency alternating magnetic field generated by the coil generates an eddy current in the metal wall, and the induced back emf generated in the coil due to the influence of this eddy current. The power is detected by a differential amplifier 63 or the like. The defect 91 on the inspection surface 9 can be detected because the eddy current is disturbed at the defect location on the inspection surface and this appears as a change in the induced back electromotive force.

However, in the flaw detection method using the eddy current flaw detector 4, the lift-off change has a considerable influence on the output signal of the detection coil 41, so a phase analysis circuit has conventionally been used in order to remove this effect and obtain only the flaw signal. There is.

In the embodiment shown in FIG.
1 and 62 and synchronous detectors 64 and 65 constitute the phase analysis circuit. How the circuit performs phase analysis on the test signal V _d will be explained with reference to FIGS. 5 and 8. FIG. 8 is an impedance plane in which the excitation high-frequency signal F _p from the oscillator 60 is taken as a phase reference signal on the R axis, and the signal in the direction perpendicular to this is taken as the J axis.

The principle of phase analysis is that, as shown in Figure 8, the coil output V _l , which is caused only by lift-off fluctuations when the flaw detector is scanning a defect-free inspection surface, is a standard deviation from the R axis by phase θ. Although it occurs in the phase direction, the coil output V _d when there is a defect on the inspection surface utilizes the fact that the phase is shifted by a minute angle dθ.

The test signal V _d detected by the detection coil 41 and amplified by the differential amplifier 63 is input to a first synchronous detector 64 and a second synchronous detector 65 . The high frequency signal F _p from the oscillator 60 is guided to a 360 degree phase shifter 61 and a 90 degree phase shifter 62 . The 360 degree phase shifter 61 uses the high frequency signal F _p as a phase reference signal,
Outputs a control signal in the standard phase direction (X-axis direction),
Further, the 90 degree phase shifter 62 is set in advance to output a control signal in a direction (Y-axis direction) that is 90 degrees ahead of the standard phase. The first synchronous detector 64 outputs a component of the inspection signal V _d in the control signal direction, that is, a flaw signal V _y according to the settings of the 90-degree phase shifter 62 . The second synchronous detector 65 outputs a component of the test signal V _d in the control signal direction, that is, a lift-off signal V _x according to the settings of the 360-degree phase shifter 61 .

The scratch signal V _y and the lift-off signal _V
All data will be recorded.

The position detector 11 shown in FIG.
The pulse a is input to a counter 60 to count the distance traveled. A distance signal b obtained from the counter 60 is input to a data recorder 80, and is also input to a synthesis circuit 51, which will be described later.

The image signal c captured by the television camera 5 is input to the synthesis circuit 51 together with the distance signal b,
As a result, both signals b and c are superimposed and connected to the recording signal input terminal of the first VTR 81 as an image signal d.

After the inspection surface is scanned by the above device and the inspection results are recorded on the data recorder 80 and the first VTR 81, an image signal of only the inspection surface where defects exist is scanned by the surface defect recording device of the present invention shown in FIG. and edit and record the inspection data to the second VTR 82.

The lift-off signal V _x and flaw signal V _y obtained by reproducing the data recorder 80 are generated by the defect signal generation circuit 7
2, and the distance signal b is input to the control circuit 85.

The control circuit 85 receives the synchronization signal g from the distance signal b.
Create. The synchronization signal g is the first synchronization signal in the playback mode.
1Sent as a drive control signal to VTR81,
The playback speed is synchronized so that the phase difference with the distance signal recorded in the 1VTR 81 becomes zero. No.
1The image signal h obtained by reproducing VTR81 is
Connected to the recording signal input terminal of 2VTR84.

The defect signal generation circuit 72 is as shown in FIG.
They each include a pair of filters 74 and 75, waveform shaping circuits 76 and 77, and an AND circuit 78. The lift-off signal V _x and the flaw signal V _y are input to filters 74 and 75, respectively, to remove low frequency components of lift-off fluctuations caused by the swinging of the eddy current flaw detector 4, and are further processed into rectangular shapes by waveform shaping circuits 76 and 77. It is shaped into waves V _x ′ and V _y ′. Both rectangular waves V _x ′ and V _y ′ are input to an AND circuit 78 and are ANDed with each other. When a defect 91 exists on the inspection surface 9, peaks appear simultaneously in the lift-off signal V _y and the flaw signal V _x , so the rectangular waves V _x ′ and V _y ′ both become H level, and the AND circuit 78 outputs a pulse. defect signal
You can get Vp.

It should be noted that the defect signal generation circuit 72 can be constructed from other electric circuits, and can of course be replaced by microcomputer software.

As shown in FIG. 7, the control signal generation circuit 73 is a one-shot multivibrator equipped with a retriggerable monomulti 73a, and is configured to generate the defect signal.
When V _p is input, a specific number T of pulse signals defined by the values of the resistor R and capacitor C are obtained from the terminal Q, and the signal obtained from the inverted output terminal is used as the control signal V _c to the pause input terminal of the second VTR 84. is input to.

The second VTR 84 is set and maintained in pause mode, and when the control signal V _c is input,
While the signal V _c is at L level, the pause mode is canceled and the recording mode is entered.

In this way, the second VTR 84 records a superimposed image of the inspection surface where the defect exists and a number indicating the distance from the inspection start position to the position where the defect exists. Therefore, after the inspection is completed, the VTR
By reproducing 84, the defect situation can be quickly grasped.

It should be noted that the surface defect detection device according to the present invention is not limited to the illustrated embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims. For example, in the embodiment _described above, the flaw signal V _y and lift-off signal V It is also possible to record the signal.

Furthermore, in the above embodiment, the defect recording device shown in FIG. 1 and the defect detection device shown in FIG. 4 are configured separately and independently, but the two devices are connected online.
It is also possible to record the entire inspection surface and edit and record only the defective area at the same time.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a surface defect recording device according to the present invention, FIG. 2 is a schematic diagram of a tube inner surface inspection device, and FIG.
The figure is a cross-sectional view of the eddy current flaw detector, Figure 4 is a block diagram of the electric circuit installed in the inspection device shown in Figure 2, Figure 5 is a block diagram of the signal processing section, and Figure 6 is a block diagram of the defect signal generation circuit. 7 is a block diagram of the control signal generation circuit, and FIG. 8 is an impedance plan view explaining the principle of phase analysis. 1...Self-propelled vehicle, 4...Eddy current flaw detector, 5...TV camera, 80...Data recorder, 81...No.
1VTR, 84...2nd VTR.

Claims (1)

[Claims] 1. An inspection signal obtained by scanning the inspection surface with a defect detector, an image signal obtained by an imaging device that photographs the scanned area of the detector, and an inspection signal obtained by scanning the inspection surface with a defect detector, A second recording means that can be controlled by an ON-OFF control signal is connected to the first recording means in which a position signal indicating a scanning position is recorded, and a second recording means is connected to the first recording means in which a position signal indicating a scanning position is recorded. At least an image signal and a position signal are input to the second recording means, and the inspection signal is input to a signal processing circuit and converted into a defect signal indicating the presence of a defect on the inspection surface, and the defect signal is input to the second recording means. A surface defect recording device connected to the second recording means as a signal for ON-controlling the means. 2. The surface defect recording device according to claim 1, wherein the defect detector is an eddy current flaw detector 4. 3. The first recording means comprises a data recorder 80 on which inspection signals and position signals are recorded, and a first VTR 81 on which image signals are recorded. Recording device. 4. The surface defect recording device according to claim 3, wherein the second recording means is a second VTR 84. 5 The inspection signals recorded in the first recording means include a lift-off signal Vx based on a change in the distance between the eddy current flaw detector 4 and the inspection surface 9, and a defect 91 on the inspection surface.
The signal processing circuit consists of a flaw signal Vy based on
It consists of a defect signal generation circuit 72 that generates a pulse indicating the presence of a defect from both the signals Vx and Vy, and a control signal generation circuit 73 whose output level is switched at the same time as the generation of the pulse and the level is maintained for a predetermined period of time. A surface defect recording device according to claim 2.