JPH0783855A - Method and device for detecting deterioration of insulated-wire covering - Google Patents

Abstract

PURPOSE:To provide a method and a device for detecting the deterioration of an insulated-wire covering in which non-destructive measurements of an insulated wire are made to quantitatively determine the degree of deterioration of the insulating covering with ease. CONSTITUTION:A device for detecting the deterioration of an insulated-wire covering comprises an input device 4 for measuring the surface condition of an insulating covering while scanning a pair of a light-emitting element 5 and a photocell 6 in the longitudinal direction of the insulated wire, an A/D coverter 7 for converting received analog signals into signals in series, a waveform memory device 8 for string the signals as lines of waveform data, an arithmetic unit 9 for creating a distribution of frequencies of occurrence from the lines of waveform data, for calculating from the distribution of frequencies of occurrence the level of a threshold for detecting cracks, and for determining the degree of deterioration of the insulating covering from the number of cracks, and an output device 11 for outputting and displaying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for nondestructively detecting deterioration of an insulating coating of an insulated wire.

[0002]

2. Description of the Related Art Conventionally, as a method or apparatus for detecting the deterioration of the insulation coating of an insulated wire, a voltage is applied between the core wire and the insulation coating while a plurality of linear electrodes are in contact with the surface of the insulated wire. However, there is a device that utilizes electricity when the electrode enters an area where the core wire is exposed (Shokai Sho 61-
131674). FIG. 9 shows an example of inspection by the energization method. In the figure, 21 is a core wire of an insulated wire, 22 is an insulating coating, 23 is a linear electrode, 24 is a detector, 25 is a power supply, 26
Indicates a cracked portion of the insulating coating.

There is also a method of detecting the degree of deterioration by collecting the gas generated from the insulating coating and analyzing the components and amount in the gas (Japanese Patent Laid-Open No. 3-107778).
Issue). FIG. 10 shows an example of inspection by the gas analysis method. In the figure, 31 is an insulated wire, 32 is a gas reservoir cover, 33
Indicates a gas reservoir, 34 indicates a tube, and 35 indicates a stopper.

Since the energization method utilizes mechanical contact between the core wire and the electrode, it cannot detect cracks in a closed state or minute cracks, and a detection current flows through the core wire when energized. There was a problem that it was difficult to apply to the wire. The gas analysis method has limited measurement points,
There are drawbacks such as increased cost of deterioration detection.

[0005]

SUMMARY OF THE INVENTION The present invention has been proposed in order to improve the above-mentioned drawbacks, and its purpose is to measure an insulated wire in a nondestructive manner and measure the degree of deterioration of the insulating coating.
An object of the present invention is to provide a method and an apparatus for detecting deterioration of an insulated wire coating that can be grasped easily and quantitatively.

[0006]

The solution to the above-mentioned problems can be achieved by adopting the novel characteristic construction method and means listed in the following by the present invention.

That is, the first feature of the method of the present invention is that the reflection intensity sequence of the surface of the insulating coating obtained by scanning the optical sensor consisting of the light emitting element and the light receiving element pair in the longitudinal direction of the insulated wire by a predetermined distance. (1) Each amplitude value of the reflection intensity sequence, that is, the brightness value is read, the number of appearances for each brightness value is counted, and the distribution of the appearance frequency is obtained. (2) The brightness with the maximum appearance frequency from the appearance frequency distribution The value I _max is found, the appearance frequency distribution is traced in the direction in which the brightness value decreases from I _max , and the brightness value I _{raise at} which the appearance frequency first becomes zero.
_Is detected and an intermediate value I _TH (= I _rais) between I _raise and zero brightness value is detected.
_e / 2), that is, the threshold value is obtained, and (3) the number of locations where the brightness value is lower than the threshold value in the reflection intensity sequence,
That is, the method is (4) a method of detecting deterioration of an insulating coating of an insulated wire, which comprises: (4) quantifying the degree of deterioration of the insulating coating from the number of cracks, and detecting the deterioration of the insulating coating thereby.

A second feature of the method of the present invention is that the reflection intensity array on the surface of the insulation coating is measured by a photosensor array consisting of a plurality of light emitting elements and light receiving elements arranged linearly along the longitudinal direction of the insulated wire. Using (1) each amplitude value of the reflection intensity sequence,
That is, the brightness value is read, the number of appearances for each brightness value is counted, the distribution of the appearance frequency is obtained, and (2) the brightness value I _max that maximizes the appearance frequency is found from the appearance frequency distribution.
tracking frequency distribution in a direction in which the brightness value decreases from _max, first frequency detects the luminance value I _{The raise} becomes zero, an intermediate value I _TH of I _{The raise} luminance value zero ₍₌ I rais _e /
2), that is, the threshold value is obtained, and (3) the number of locations where the brightness value is lower than the threshold value in the reflection intensity sequence, that is, the number of cracks, and the width during the decrease, that is, cracks. This is a method for detecting deterioration of the insulation coating of an insulated wire, which comprises measuring the width and (4) quantifying the degree of deterioration of the insulation coating from the number of cracks and the maximum crack width, and detecting the deterioration of the insulation coating by this.

The device of the present invention is characterized in that it uses an optical sensor consisting of a pair of a light emitting element and a light receiving element, a means for measuring a reflection intensity sequence in the longitudinal direction of an insulated wire, a circuit for fetching and storing the reflection intensity sequence as waveform data, And a device for detecting deterioration of an insulated wire coating, which is provided with a circuit including the following computing means.

(1) A means for reading each amplitude value of the reflection intensity sequence, that is, a luminance value, counting the number of appearances for each luminance value, and obtaining a distribution of appearance frequencies, (2) a maximum appearance frequency from the appearance frequency distribution The luminance value I _max is found, and the appearance frequency distribution is traced in the direction in which the luminance value decreases from I _max ,
First, the brightness value I _raise at which the appearance frequency becomes zero is detected, and I _raise
raise the luminance value zero intermediate value _{I TH (= I rais e /} 2), i.e. means for obtaining the threshold point being lower than the threshold luminance value among the (3) reflection intensity column Number, that is, a means for measuring the number of cracks, (4) means for identifying the degree of deterioration of the insulating coating from the number of cracks.

[0011]

With the above means, the present invention can perform the nondestructive inspection quickly and easily because the measurement can be performed only by bringing the optical sensor into contact with the surface of the insulated wire.

Further, since the brightness level of the crack is relatively determined from the brightness level of the coating color of the cable, it is possible to detect the crack independent of the cable color.

Furthermore, since the deterioration of the insulating coating is quantified from the frequency of occurrence of surface cracks, it is possible to perform deterioration diagnosis independent of the inspector's subjectivity and skill.

[0014]

EXAMPLES Next, examples of the present invention will be described.

One embodiment of the present invention is a CCP for telecommunications.
(Color Coded Polyethylene) A cable deterioration detection method will be described as an example.

FIG. 1 is a block diagram of a deterioration detecting device for realizing the method for detecting deterioration of an insulated wire coating according to claims 1 and 2 according to the present invention. The deterioration detecting device includes a main body 1 and an insulated wire holder 2. 3 is an insulated wire.

As shown in FIG. 2, the main body 1 further includes an input device 4 for measuring the surface of the insulating coating, an A / D converter 7 for converting an input signal from analog to digital, and a digital signal for data (waveform data). As a waveform storage device 8, a calculation device 9 for performing a predetermined calculation on the waveform data to detect cracks and estimating the degree of deterioration, and a deterioration degree reference database 10 in which data for estimating the deterioration degree is accumulated. The output device 11 outputs the estimation result. The input device 4 is composed of a pair of a light emitting element 5 and a light receiving element 6. The method of claim 2 is a method in which a plurality of elements (each 204
The case where eight elements are arranged in a straight line will be described.)
The method of claim 1 comprises a pair of receiving and emitting elements.

FIG. 3 is a flow chart showing a processing flow of the deterioration detecting method according to the second aspect. As shown in FIG. 1, the electric wire 3 to be measured is sandwiched between the holders 2, the light emitted from the light emitting element 5 of the input device 4 is applied to the coating surface, and the reflected light is received by the light receiving element 6, whereby the surface of the insulating coating is obtained. The state is measured linearly (measurement step).

The received analog signal is quantized by the A / D converter 7 to a predetermined gradation (256 gradations in this example), converted into a digital signal (A / D conversion step), and further, the waveform storage device. 8 is a waveform data sequence Sn (n = 0 to 2
047) (waveform storing step). FIG. 4 shows an example of waveform data of a deteriorated insulated wire. (A) shows the appearance of the electric wire 3 to be measured, and the dotted line in the figure is a scanning line XX 'measured by the light emitting and light receiving elements 5 and 6.
(B) shows the measured waveform data, the horizontal axis is the number of scanning pixels, and the vertical axis is the brightness value i. The cracks a1, a2, a3 generated on the insulating coating due to the deterioration lower the brightness value at that position due to the shadow. Note that the brightness value does not always become constant even on a healthy coating, and the value fluctuates due to the effects of stains, color unevenness, and the like.

The arithmetic unit 9 counts the number of appearances for each luminance value from the waveform data and creates an appearance frequency distribution (waveform analysis step 1). FIG. 5 is an appearance frequency distribution obtained from the waveform data shown in FIG. The horizontal axis is the luminance value i, the vertical axis represents the cumulative number n _i of the number of occurrences of luminance values. In the figure, the distribution lump b1 reflects the color of the ground of the insulating coating, and the distribution lump b
2 reflects the color of the shadow caused by the crack.

Further, the arithmetic unit 9 automatically calculates the threshold level I _th for distinguishing the ground of the insulation coating from the shadow of the crack by the following method (waveform analysis step 2). First, the brightness value I _max giving the maximum cumulative number from the appearance frequency distribution.
When the appearance frequency distribution is traced in the direction in which the luminance value decreases from I _{max, the} point at which the cumulative number becomes zero is detected first, and the intermediate value between the luminance value I _raise and the luminance value 0 at that point is detected. _Be I _th (= I _raise / 2, hereinafter referred to as a threshold).

Next, the arithmetic unit 9 counts the number of locations in the waveform data where the luminance value is lower than the threshold level, and further measures the maximum value of its width (pixel number). (Waveform analysis step 3). These values are regarded as the number of cracks and the maximum crack width, respectively. FIG. 6 is an explanatory diagram showing how the cracks a1, a2, and a3 are detected from the waveform data and the threshold value I _th . (A) is the waveform data, and the luminance value indicated by the dotted line in the figure is the threshold I _th level.
(B) shows the position of the crack and the detection result of the crack width (the number of pixels), where there are 3 cracks and the maximum crack width is 3 pixels (dots).

Finally, the arithmetic unit 9 refers to the deterioration determination table which has been converted into data in advance in the deterioration degree reference database 10 to determine the degree of deterioration from the number of detected cracks and the maximum crack width (deterioration estimation work point). FIG. 7 shows a deterioration judgment table used for judging deterioration of the insulation coating of the CCP cable. The degree of deterioration is uniquely determined from the distribution range of the number of cracks and the maximum crack width (number of pixels) with respect to the deterioration of the insulating coating. Table 1 shows the relationship between the degree of deterioration and its state.

[0024]

[Table 1] The output device 11 outputs and displays the degree of deterioration (result output).

FIG. 8 is a flow chart showing a processing flow of the deterioration detecting method according to the first aspect. Since the method of claim 1 is a point measurement using a pair of light receiving and emitting elements, it differs from the method of claim 2 in the following points.

The measuring step and the scanning step are performed in parallel, only the number of cracks is measured in the waveform analyzing step 3, and the degree of deterioration is determined only from the number of cracks in the deterioration estimating step. That is, while scanning the pair of the light emitting element 5 and the light receiving element 6 of the input device 4 in the longitudinal direction of the insulated wire, the surface state of the insulating coating is measured (measuring step, scanning step). / D converter 7
The analog signals received by are sequentially converted into digital signals (A / D conversion step) and stored as waveform data strings by the waveform storage device 8 (waveform storage step).

Next, the arithmetic unit 9 creates an appearance frequency distribution from the waveform data string (waveform analysis step 1), and calculates a threshold level for detecting a crack from the appearance frequency distribution (waveform analysis step 1). 2) Measure the number of cracks (waveform analysis step 3).

Finally, the arithmetic unit 9 determines the degree of deterioration of the insulating coating from the number of cracks (deterioration estimating step), and the output unit 11
Is output and displayed (result output).

[0029]

As described above, according to the present invention,
Machines can perform absolute and quantitative judgment actions that have so far depended on the experience and skills of inspectors.

Further, since it is an optical measurement, nondestructive, simple and quick measurement is possible.

Further, in the present invention, since the crack detection level is appropriately selected for each measurement, deterioration can be detected without depending on the color of the insulating coating.

[Brief description of drawings]

FIG. 1 is a perspective view showing a deterioration detecting device for an insulated wire coating according to the present invention.

FIG. 2 is a structural explanatory view showing a deterioration detecting device for an insulated wire coating of the present invention.

FIG. 3 is a flowchart showing a processing flow of a method according to claim 2 of the present invention.

FIG. 4 is a schematic diagram of waveform data obtained when a deteriorated insulated wire according to the present invention is measured, in which (a) shows an appearance and a measurement line of an electric wire to be measured, and (b) shows measured waveform data.

FIG. 5 is a characteristic diagram showing an appearance frequency distribution and threshold values obtained from the waveform data according to the present invention.

FIG. 6 is a schematic diagram showing how a crack is detected from waveform data and a threshold value according to the present invention, in which (a) is waveform data;
(B) is a characteristic view showing a detection result of a crack and a crack width.

FIG. 7 is an explanatory diagram showing an example of a deterioration determination table for determining the degree of deterioration when the insulation coating of the CCP cable according to the present invention is diagnosed.

FIG. 8 is a flowchart showing a processing flow of a method according to claim 1 of the present invention.

FIG. 9 is an explanatory diagram showing a deterioration detection method by a conventional energization method.

FIG. 10 is an explanatory diagram showing a deterioration detection method by a conventional gas analysis method.

[Explanation of symbols]

1 ... Body part, 2 ... Insulated wire holder, 3 ... Insulated wire, 4 ...
Input device, 5 ... Light emitting device, 6 ... Light receiving device, 7 ... A / D converter, 8 ... Waveform storage device, 9 ... Arithmetic device, 10 ... Degradation standard database, 11 ... Output device.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroaki Shindo 1-6, Uchiyuki-cho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Inventor Junichi Masuda 1-6, Uchisaiwai-cho, Chiyoda-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (3)

[Claims] 1. An amplitude value of each reflection intensity sequence is obtained by using a reflection intensity sequence of an insulating coating surface obtained by scanning an optical sensor including a pair of a light emitting element and a light receiving element in the longitudinal direction of an insulated wire for a predetermined distance. That is, the luminance value is read, the number of appearances for each luminance value is counted, the distribution of the appearance frequency is obtained, the luminance value I _max having the maximum appearance frequency is found from the appearance frequency distribution, and the luminance value decreases from I _max. First, the luminance value I _raise at which the appearance frequency becomes zero is detected by tracing the appearance frequency distribution, and the intermediate value I _TH between I _raise and the luminance value zero, that is, the threshold value is obtained, and in the reflection intensity sequence, It is characterized in that the number of places where the brightness value is lower than the threshold value, that is, the number of cracks is measured, the degree of deterioration of the insulation coating is quantified from the number of rows and the deterioration of the insulation coating is detected. How to detect deterioration of insulated wire coating . 2. A reflection intensity array on the surface of the insulating coating, which is measured by an optical sensor array consisting of a plurality of light emitting elements and light receiving element pairs linearly arranged along the longitudinal direction of the insulated wire. The amplitude value, that is, the brightness value is read, the number of appearances for each brightness value is counted, the appearance frequency distribution is obtained, the brightness value I _{max at} which the appearance frequency is maximum is found from the appearance frequency distribution, and the brightness value is reduced from I _max. The luminance frequency value I _{raise at} which the frequency of appearance is zero is detected by tracing the appearance frequency distribution in the following direction, the intermediate value I _TH between I _raise and the luminance value zero, that is, the threshold value is obtained, and The number of places where the brightness value is lower than the threshold value, that is, the number of cracks, and the width during the decrease, that is, the crack width are measured, and the degree of deterioration of the insulation coating is calculated from the number of cracks and the maximum crack width. Quantification of Deterioration detecting method for an insulated wire coating, characterized in that the detection. 3. A means for measuring a reflection intensity sequence in the longitudinal direction of an insulated wire using an optical sensor consisting of a light emitting element and a light receiving element pair, a circuit for fetching and storing the reflection intensity sequence as waveform data, and A unit that reads each amplitude value, that is, a brightness value, counts the number of appearances for each brightness value, and obtains a distribution of appearance frequencies, and a brightness value I that maximizes the appearance frequency from the appearance frequency distribution.
_Max is found, and then the appearance frequency distribution is traced in the direction in which the luminance value decreases from I _{max, the} luminance value I _raise at which the appearance frequency becomes zero is detected first, and the intermediate value I _TH between I _raise and the luminance value I _TH is detected. , That is, the means for obtaining the threshold value, and the number of locations in the reflection intensity sequence where the luminance value is lower than the threshold value,
That is, a deterioration detecting device for an insulated wire coating, comprising: an arithmetic circuit including a unit for measuring the number of cracks and a unit for identifying the degree of deterioration of the insulating coating from the number of cracks.