JPH11295149A - Wire color judgment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately judge a color at each point by photographing the surface of an electric wire with a color camera, determining RGB intensity at each point on the surface via an image analysis, determining brightness, saturation and hue from the RGB intensity, calculating a specific equation, and selecting the minimum value. SOLUTION: The surface of a test electric wire 6 is photographed by a color camera main body 9, a color image is image-analyzed, and the red (R), green (G), blue (B) intensity at one split point of the image is converted by a frame memory 10. A personal computer 12 calculates brightness I, saturation S and hue H from the RGB intensity and obtains the brightness I of the expected color N as I1 -In , the saturation S as S1 -Sn , and hue H as H1 -Hn . Ln is calculated by an equation, and the color giving the minimum value of Ln is judged as the color of the split point, where n=1 through N, and Win , WSN, Whm are the weighted values of the brightness I, saturation S and hue H of the color N respectively. The color of the outer periphery insulating cover layer of the electric wire 6, the presence or absence of an identification mark, color and shape can be automatically judged quickly and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for determining the color of an electric wire. More specifically, the present invention relates to a method for judging the color of an electric wire capable of automatically judging the color of an outer peripheral coating layer of an electric wire, the color of an identification mark, and the like.

[0002]

2. Description of the Related Art Electric wires are widely used as arteries for electric power, communication, various devices and the like.

[0003] Generally, the outer periphery of an electric wire is covered with an insulating layer or a sheath layer. These insulating layers and sheath layers are not colorless, and usually have the original natural color of the insulating layer or sheath layer material or white, gray, red, orange, blue, yellow, green, or purple due to pigments or coloring agents. It is colored in various colors such as brown, black and the like.

[0004] In addition, depending on the electric wire, not only the outer peripheral coating layer is colored, but also various identification marks may be added to the colored outer peripheral coating layer.

FIGS. 4 to 8 show examples in which the outer peripheral coating layer of such an electric wire is colored and an identification mark is given to the colored outer peripheral coating layer.

FIG. 4 is a perspective view of an electric wire having a colored outer insulating coating layer.

In FIG. 4, reference numeral 1 denotes a conductor, and 2 denotes a colored peripheral insulating coating layer.

The color of the electric wire in FIG. 4 is one color of the colored outer peripheral insulating coating layer.

FIG. 5 is a perspective view of an electric wire in which the outer peripheral insulating coating layer is colored and a straight line mark different from the color of the outer peripheral insulating coating layer is continuously provided along the longitudinal direction of the outer peripheral insulating coating layer. It is a thing.

In FIG. 5, reference numeral 3 denotes a straight line mark.

The electric wire shown in FIG. 5 has a total of two colors, that is, a colored outer peripheral insulating coating layer and a straight line mark.

FIG. 6 is a perspective view of an electric wire in which the outer peripheral insulating coating layer is colored and a ring mark of a color different from the color of the outer peripheral insulating coating layer is provided at predetermined intervals along the longitudinal direction of the outer peripheral insulating coating layer. It is shown.

In FIG. 6, reference numeral 4 denotes a ring mark.

The colors of the electric wire in FIG. 6 are a total of two colors, that is, a colored outer peripheral insulating coating layer and a ring mark.

FIG. 7 shows a line mark of a color different from the color of the peripheral insulating coating layer along the longitudinal direction of the peripheral insulating coating layer, and a color and a linear mark of the peripheral insulating coating layer. FIG. 2 is a perspective view of an electric wire provided with a ring mark of a color different from that of FIG.

In FIG. 7, 3 is a straight line mark, and 4 is a ring mark.

The colors of the electric wire in FIG. 7 are a total of three colors of a colored outer peripheral insulating coating layer, a straight line mark and a ring mark.

FIG. 8 is a perspective view of an electric wire in which the outer peripheral insulating coating layer is colored and a dot mark of a color different from the color of the outer peripheral insulating coating layer is provided at predetermined intervals along the longitudinal direction of the outer peripheral insulating coating layer. It is shown.

In FIG. 8, reference numeral 5 denotes a dod mark.

The colors of the electric wire in FIG. 8 are a total of two colors, that is, a colored outer peripheral insulating coating layer and a dod mark.

A. The conventional color blind inspection method The colors and identification marks of these wires are strictly specified in the manufacturing specifications. Inspection is made before shipment.

This inspection procedure is generally performed as follows.

What is the color of the outer insulating coating layer? Whether the identification mark is given to the outer insulating coating layer,
or not? If an identification mark is given to the outer insulating coating layer, what is its color? If the identification mark is provided on the outer insulating coating layer, is the identification mark provided in an appropriate shape and size? Conventionally, the inspection work of (1) to (5) has been performed by an inspector by silent inspection.

However, the electric wire to be manufactured is extremely long, so that the inspector performs a silent inspection over the entire length, which requires a lot of inspection man-hours, and there is a concern that the wire is erroneously recognized.

B. Conventional Image Processing Inspection Methods Therefore, application of an image processing inspection method has been studied to improve such difficulties.

However, the conventional image processing inspection method is a method of extracting and inspecting a specific color from an image, and cannot determine the color or the presence or absence of an identification mark. No judgment could be made.

For example, an electric wire as shown in FIG. 6, ie, in this case, the outer peripheral insulating coating layer is colored dark brown, and a predetermined interval is provided along the longitudinal direction of the outer brown insulating coating layer colored dark brown. Then, the result of inspecting the electric wire provided with the light brown ring mark and inspecting the electric wire by the conventional automatic image processing inspection method will be described.

First, the surface of the electric wire was photographed with a color camera.

Next, the captured image is converted into three images by the three primary color analyzer.
The intensity of the primary color signals (R signal, G signal, B signal) was analyzed.

FIG. 9 is a graph showing the relationship between the distance from the center of the electric wire hit by the color camera to both sides in the circumferential direction and the R signal strength.

FIG. 10 is a graph showing the relationship between the distance from the center of the electric wire hit by the color camera to both sides in the circumferential direction and the G signal intensity.

FIG. 11 is a graph showing the relationship between the distance from the center of the electric wire hit by the color camera to both sides in the circumferential direction and the B signal strength.

As can be seen from FIGS. 9 to 11, the intensities of the R signal, G signal, and B signal of the wire fluctuate greatly as they deviate in the circumferential direction from the center position of the wire hit by the color camera. This is probably because the shape of the electric wire is cylindrical, so that it is difficult to irradiate and reflect uniform light on the surface of the electric wire. Therefore, photograph the surface of the wire with a color camera,
It is difficult to determine the color of the electric wire and the ring mark by analyzing the intensity of the three primary color signals for the image.

[0034] c. R, G, and B signal brightness I, color
The conversion method to the degree S and the hue H. Then, the respective intensities of the R signal, the G signal and the B signal are further changed to the lightness I
I examined it after converting it to saturation S and hue H.

According to the “Tokyo University Press”, a conversion method based on a hexagonal pyramid color model, a conversion method based on a bihexagonal pyramid color model, a conversion method based on the definition of Haydn, and the like are described. A calculation method was used. That is, the intensity of R, G, B output from the color camera is 0 to 25.
Assuming a range of 8 bits of 5, the following equation (2)
(3) was calculated by equation (4).

[0036]

(Equation 1)

[0037]

(Equation 2)

[0038]

(Equation 3)

Using these formulas, distributions of lightness, saturation, and hue were obtained from electric wires whose colors were already known.

FIG. 12 is a graph showing the relationship between the distance from the center position of the electric wire hit by the color camera to both sides in the circumferential direction and the lightness I.

FIG. 13 is a graph showing the relationship between the distance from the center of the electric wire hit by the color camera to both sides in the circumferential direction and the saturation S.

FIG. 14 is a graph showing the relationship between the distance from the center of the electric wire hit by the color camera to both sides in the circumferential direction and the hue H.

As can be seen from FIG. 12, the lightness I is high in a portion that receives strong illumination and reflects brightly, and conversely, a portion that receives weak illumination and reflects darkly is low.

As can be seen from FIG. 13, the saturation S is opposite to the brightness I, and the portion which is strongly illuminated and reflects brightly is low, and the portion which is weakly illuminated and reflects darkly is high. ing.

As can be seen from FIG. 14, the hue H has a constant value irrespective of the distance from the center position of the electric wire hitting the color camera to both sides in the circumferential direction. That is, the hue H
Can be accurately measured without being affected by the lighting position and brightness of the electric wire.

The reason why the difference between the hue H of the outer insulating coating layer and the hue H of the ring mark is small is presumably because the difference between dark brown and dark brown is small. In other words, if the color of the outer peripheral insulating coating layer is different from the color of the ring mark, it is considered that the difference between the hue H of the outer peripheral insulating coating layer and the hue H of the ring mark increases.

As described above, the surface of the electric wire is photographed by the color camera, the intensity of the three primary color signals is analyzed with respect to the image, and the respective intensities of the R, G, and B signals obtained therefrom are converted into lightness I and saturation S. , The hue H of the outer peripheral insulating coating layer of the electric wire and the hue H of the ring mark can be accurately determined.

[0048] d. Upper and lower limits of lightness I, saturation S, and hue H
Judgment Method Next, a method of judging the upper limit and lower limit of lightness I, chroma S, and hue H will be described.

In the color determination method, it may be difficult to determine two similar colors.

Therefore, an experiment was conducted on a method of determining the upper limit and lower limit of lightness I, saturation S, and hue H of an electric wire having an outer peripheral insulating coating layer and an identification mark colored in a representative color.

First, an electric wire having a peripheral insulating coating layer colored in a representative color and an identification mark was prepared.

Next, the surfaces of these electric wires were illuminated.

At this time, when the camera was viewed from directly above the electric wire, lighting was applied from the side so that light reflected on the electric wire did not directly enter the camera.

Next, an image was shot with a color camera.

Next, the captured image is converted into an R signal, a G signal, and a B signal.
The signal was analyzed.

Next, the obtained R signal, G signal, B signal
Each intensity of the signal was converted into lightness I, saturation S, and hue H.

Finally, their lightness I, saturation S, hue H
Was plotted as a graph.

In the graph, the horizontal axis is the angle (120 ° angle is the center position of illumination), and the vertical axis is the frequency for brightness I, saturation S, and hue H.

FIG. 15 is a lightness distribution graph for a colored electric wire.

FIG. 16 is a saturation distribution graph for a colored electric wire.

FIG. 17 is a hue distribution graph for a colored electric wire.

A. Results of Analysis of Lightness Distribution Graph As can be seen from FIG. 15, the brightest color is sky blue, followed by pink, blue, purple and the like. On the other hand, the darkest color is brown, followed by red and gray.

Since the electric wire has a round shape, it is difficult to uniformly illuminate the electric wire. As a result, a bright place and a dark place occur.
Therefore, the lightness distribution is distributed over a wide range, and the respective colors overlap. This means that the colors cannot be separated.

B. Analysis result of saturation distribution graph As can be seen from FIG. 16, the largest saturation is red,
It is followed by orange and blue. On the other hand, the lowest saturation is gray, followed by pink, purple, sky blue, and brown.

Here, the gray color having the smallest saturation should theoretically have a saturation of zero, but the reason why the saturation did not become zero was that the variation in R, G, B of the color camera and the illumination light were completely This is because it is not white light.

As can be seen from FIG. 16, the saturation of red and the saturation of orange overlap, and the saturations of pink, purple, sky blue, and brown also overlap.

C. Analysis result of hue distribution graph Gray varies over a wide range.

On the other hand, all colors other than gray have a small variation and a limited range.

However, the brown and orange colors have the same hue.

Further, brown, orange, red and pink colors have overlapping portions. Therefore brown, orange,
Even if the upper and lower limits of the hues such as red and pink are set, they cannot be specified separately.

[0071]

As described above, since the electric wire is a long cylindrical body having a small outer diameter, it is difficult to uniformly illuminate the surface with a light or the like.

For this reason, for each color of the electric wire having the outer peripheral insulating coating layer and the identification mark colored in a representative color, even if those colors are converted into lightness I, saturation S, and hue H, respectively, the lightness I, Saturation S and hue H often overlap each other. For example, a wire whose outer peripheral insulating coating layer is colored red will be judged orange when viewed from a certain point. Also, the color of a certain point does not belong to any color.

As described above, according to the conventional technique, the lightness I, the saturation S, and the hue H are measured with respect to the color of the electric wire, and then, the lightness I, the saturation S, and the hue H are determined according to the upper limit to lower limit of the manufacturing specification. It was difficult to judge whether or not it was in.

The present invention has been made in view of such a point, and an object of the present invention is to solve the above-mentioned drawbacks of the prior art. An object of the present invention is to provide a wire color determination method that can accurately determine the color of each point by automatically performing arithmetic processing.

[0075]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a wire color determination method for determining the color of a wire composed of several colors out of N colors expected in advance. First, a color image is obtained by taking an image of the electric wire surface with a color camera, and then the color image is subjected to image analysis to obtain a R at a point where the color image is subdivided.
(Red), G (green), and B (blue) are calculated, and then lightness I, saturation S, and hue H are calculated from the R (red), G (green), and B (blue) intensities. And then calculate the lightness, saturation, and hue of the N colors as I ₁ , S ₁ , H ₁ , I ₂ , S ₂ , H ₂ , I ₃ ,
_{S 3, H 3, I 4} , S 4, H 4 .................., I n, S
_n, it calculates the L _n by Equation (1) below when the H _n,
Thereafter the certain color which gives the minimum value among the L _n to the color determination method of an electric wire, which comprises determining the color of subdivision was a point of the wire surface.

L _n = W _in (I−I _n ) ² + W _SN (S−S _n ) ² + W _hm (H−H _n ) ² (1) where n = 1, 2, 3, 4,... _{......... N W in, W SN,} W hm are each defined brightness for N color, saturation, weighting hue value i.e., color analysis of a certain point in the present invention the brightness I, the saturation S , Hue H, standard lightness I, saturation S, hue H of each color
Is compared, and the degree of approximation is quantified, and the object is achieved by estimating the closest one as the color of the point. For example, since there is no hue in white, gray and black, the weight for hue is set to 0, and in other colors, the hue is not influenced by the brightness of the illumination, so the weight is increased. The variation in brightness and saturation is white, gray,
Since the color becomes larger than the hue except for black and the like, the weight is reduced. In the present invention, the brightness I, the saturation S, and the hue H of many points are further determined from a sample whose color is already known.
Are calculated and the standard value is set as the average value of the distribution of the lightness I, the saturation S, and the hue H, and the weighting is obtained by using the variance to easily obtain a color judgment standard. I have.

[0077]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the method for determining the color of an electric wire according to the present invention will be described.

FIG. 1 is a perspective view showing an electric wire color judgment apparatus used in an embodiment of the electric wire color judgment method of the present invention.

In FIG. 1, 2 is an electric wire, 6 is a light, 7 is a lens, 8 is a color camera body, 9 is a signal wire, 10 is a frame memory (image processing board), 11 is a monitor television, 12 is a personal computer, and 13 is a personal computer. It is a personal computer display.

The frame memory 10 is a personal computer 12
It is built into a personal computer as an extension board.

(Outline of Wire Color Determining Apparatus shown in FIG. 1) Next, an embodiment of the wire color determining method of the present invention performed by the wire color determining apparatus of FIG. 1 will be described.

First, a test wire 6 for measuring a color is prepared.

Next, the light 6 is illuminated at an angle closer to the horizontal than the axial direction of the test wire 6.

Next, the color camera body 8 is fixed above the test wire 6.

Here, the lens 8 is integrally mounted on the color camera body 9. The number of photographing devices including the color camera body 9 and the lens 8 may be one, or a plurality of photographing devices may be installed at predetermined angular intervals in the circumferential direction.

Next, the power of the frame memory 10, the monitor television 11, the personal computer 12, and the like is turned on.

Next, the color of the test wire 6 is photographed through the color camera body 8 and the lens 7.

A color image of the test cable 6 is displayed on the monitor television 11.

Next, the video signal of the color image of the test wire 6 is transmitted to the frame memory 10 via the signal wire 9.

Next, the frame memory 10 that has received the video signal, with respect to a point obtained by subdividing the color image of the test wire 6, converts the point into an 8-bit three primary color signal (R signal,
(G signal, B signal).

Next, the R signal, G signal, and B signal converted by the frame memory 10 are processed by the CPU of the personal computer 12 via the internal bus of the personal computer.

That is, the CPU of the personal computer 12 outputs the R signal,
The signal and the B signal are processed into brightness I, saturation S, and hue H,
Finally, the color at a certain point obtained by subdividing the color image of the test wire 6 is accurately determined.

At this time, R is displayed on the personal computer display 13.
The signal, the G signal, the B signal, the brightness I, the saturation S, the hue H, and the judgment color at a certain point on the test wire 6 are displayed.

These color determination operations can be performed automatically, accurately, and quickly.

(One Embodiment of the Wire Color Judgment Method of the Present Invention)
Next, an embodiment of the wire color determination method of the present invention performed by the wire color determination device of FIG. 1 will be described.

First, the color of the compound used for the electric wire used in one embodiment is sky, blue, purple, peach, red, brown, orange, yellow,
There are 13 colors of young grass, green, white, gray, and black, of which peach and gray are also used for printing ring marks. The color of the test wire is completely unknown, and the presence or absence of a straight line mark and a ring mark is also unknown. However, the type of test wire without dot mark shall be used.

Next, assuming that 13 colors are possible,
Using three cameras, the electric wire was photographed from three directions, and the color judgment of each point was performed according to the above-described procedure.

Table 1 shows the results of these color judgments. Note that, in Table 1, the ratio indicates the ratio of the determined colors after determining the color of each subdivided point.

[0099]

[Table 1]

As can be seen from Table 1, the judgment result shows that red is 5
Since the ratio was 7.1%, this was determined to be the ground color of the electric wire.

Next, since the ratio of blue was as large as 14.6%, it was determined that there was a blue linear mark.

Further, since the ratio of peach was 9.3%, it was estimated that there was a peach ring mark.

The ratio of purple is relatively large at 7.4%, which is considered to be due to the fact that the boundary between red and blue was determined to be purple due to the resolution of the apparatus.

Therefore, it is considered that this electric wire is composed of three colors of red, blue and peach.

Therefore, the color was re-determined using only this color as a candidate.

Table 2 shows the re-determination results.

[0107]

[Table 2]

The appearance rate in the re-judgment has no meaning other than reconfirmation of the color configuration, but the distribution of the color judgment makes it possible to judge the shape of the linear mark and the shape of the ring mark.

The figure shows a part of the result of color judgment of the images obtained from the three cameras into three colors of red, blue and peach.

As can be seen from FIG. 2, peach appears at the border between red and blue.

Therefore, FIG. 3 shows that this is removed as dust and only the shape of the peach ring mark is extracted.

From FIG. 3, the quality of the shape of the ring mark can be determined.

The above is an example in which three colors are first selected from the thirteen color candidates and final shape recognition is performed.

In the present invention, besides, it is also possible to judge a rough hue in the first judgment and to judge a fine hue in the second judgment. For example, the color of peach used for compounding electric wires is slightly different from the color of peach used for printing ring marks. Therefore,
In the first judgment, it is judged whether peach is present, and if there is a judgment rate sufficient to judge that peach is used for both the compound of the electric wire and the ring mark, the compound is judged in the second judgment. Lightness I different between
Colors can also be classified by standard values of saturation S and hue H and weighting.

[0115]

According to the method for judging the color of an electric wire according to the present invention, the color of the outer insulating coating layer of the electric wire, the presence / absence of the identification mark, the color of the identification mark, the shape of the identification mark, etc. can be quickly, easily and automatically determined. It is possible and industrially useful.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an electric wire color determination device used in an embodiment of an electric wire color determination method of the present invention.

FIG. 2 shows an embodiment of a method for determining the color of an electric wire according to the present invention, in which a test wire composed of three colors of red, blue, and orange is taken, and the color of the test wire is first determined as unknown. And confirms that those colors have been reduced to the three colors described above, and shows the color distribution when re-color determination is performed using these three colors as candidates.

FIG. 3 shows the shape of a ring mark obtained by the method for determining the color of an electric wire according to the present invention.

FIG. 4 is a perspective view of an electric wire in which an outer peripheral insulating coating layer is colored.

FIG. 5 is a perspective view of an electric wire in which an outer peripheral insulating coating layer is colored and a straight line mark different in color from the outer peripheral insulating coating layer is continuously provided along the longitudinal direction of the outer peripheral insulating coating layer. It is.

FIG. 6 is a perspective view of an electric wire in which an outer peripheral insulating coating layer is colored and a ring mark of a color different from the color of the outer peripheral insulating coating layer is provided at predetermined intervals along a longitudinal direction of the outer peripheral insulating coating layer. It is a thing.

FIG. 7 shows a color of the outer peripheral insulating coating layer, a color of the linear mark different from the color of the outer insulating coating layer along the longitudinal direction of the outer insulating coating layer, a color of the outer peripheral insulating coating layer, and a color of the linear mark. FIG. 3 is a perspective view of an electric wire provided with a ring mark of a different color from that of the electric wire.

FIG. 8 is a perspective view of an electric wire in which an outer peripheral insulating coating layer is colored and a dot mark of a color different from the color of the outer peripheral insulating coating layer is provided at a predetermined interval along the longitudinal direction of the outer peripheral insulating coating layer. It is a thing.

FIG. 9 is a graph showing a relationship between a distance from a center position of an electric wire to be illuminated to both sides in a circumferential direction and an R signal intensity.

FIG. 10 is a graph showing a relationship between a distance from a center position of an electric wire to be illuminated to both sides in a circumferential direction and a G signal intensity.

FIG. 11 is a graph showing a relationship between a distance from a center position of an electric wire to be illuminated to both sides in a circumferential direction and a B signal intensity.

FIG. 12 is a graph showing a relationship between a distance from a center position of an electric wire to be illuminated to both sides in a circumferential direction and lightness I;

FIG. 13 is a graph showing a relationship between a distance from a center position of an electric wire to be illuminated to both sides in a circumferential direction and a saturation S.

FIG. 14 is a graph showing a relationship between a distance from a center position of an electric wire hit by a color camera to both sides in a circumferential direction and a hue H;

FIG. 15 is a brightness distribution graph for a colored electric wire.

FIG. 16 is a saturation distribution graph for a colored electric wire.

FIG. 17 is a hue distribution graph for a colored electric wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor 2 Colored outer insulating coating layer 3 Straight line mark 4 Ring mark 5 Dot mark

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Naoki Ito 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside the Hitachi Cable Hidaka Factory

Claims (1)

[Claims] An electric wire color judging method for judging the color of an electric wire composed of several colors out of N colors predicted in advance, wherein the color of the electric wire is first photographed by a color camera. An image is obtained, and then the R (red), G (green), and B (blue) intensities at certain points obtained by subdividing the color image by image analysis of the color image are calculated. (Red), G (green), and B (blue) intensities I,
The saturation S and the hue H are calculated, and then the lightness, saturation,
Hue _{I 1, S 1, H 1} , I 2, S 2, H 2, I 3, S
_{3, H 3, I 4,} S 4, H 4 .................., I n,
When S _n and H _n are used, L _n is calculated by the following equation (1), and then the color giving the minimum value among the L _n is determined to be the color of a subdivided point on the wire surface. A method for determining the color of an electric wire. _{L n = W in (I-} I n) 2 + W SN (S-S n) 2 + W hm (H-H n) 2 ... (1) However, n = 1,2,3,4 ............... _{N W in, W SN, W} hm are each defined brightness for N color, saturation, hue weighting value