JPH05296715A - Measurement device for position of coiled wire material - Google Patents

Abstract

PURPOSE:To enable the overall length and posture of a coiled wire material to be obtained by finding the vertex position of the wire material at the radial upper section thereof. CONSTITUTION:Four light guides 3-4 are connected to an illuminant 4 for dividing light into four systems, and four types of lighting 3a to 3d are projected to an air-core coil 1 inserted in a board 2 from the four different radial directions thereof. An image pickup means comprising an image pickup lens 5 and a video camera 6, and an electrode actuator are synchronously operated to obtain the image signals of the four lighting systems. The image signals are inputted to an image processing device 7, converted to binary image signals and, then, saved in an image memory. A lighting system is so established that luminescent spot images 9a and 10a are available from the lighting 3a, luminescent spot images 9b and 10b available from the lighting 3b, and a superposed section is formed in the images 9a and 9b. Luminescent spots 12A and 12B on the upper external surface of the coil 1 are thereby obtained. Also, the luminescent spot gravity 15 and 16 of luminescent spot trains 12A and 12B is obtained, and the gravity center of a luminescent spot on a wire material is calculated, thereby finding the upper vertex 18 of the air-core coil 1 on the center axis thereof. The position of the wire material of the air-core coil 1 and posture thereof are obtained on the basis of the position of the vertex 18. Also, when the diameter of the wire material is known, the overall length L of the coil 1 can be found.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rod, such as an air-core coil or a spring, in which a wire rod having a glossy surface and a circular cross section is wound in a spiral shape. Is a method of performing measurement by image processing.
According to this method, it is possible to stably measure the position of the air-core coil and the like, unlikely to be affected by the glossy state of the surface of the wire or diffuse reflection from the surroundings such as the attached substrate.

[0002]

2. Description of the Related Art There is no known method for contactlessly measuring the position, posture and total length of a coiled wire (hereinafter referred to as a coiled wire) such as an air-core coil or a spring.

There have been the following problems in recognizing the position of the coiled wire by image processing. When the coiled wire is illuminated, the binarized image of the bright spots due to the reflection on the surface of the wire is generated on the upper outer surface and the lower inner surface of the object (see FIG. 1). The bright spots generated on the inner surface of the lower portion may enter the shadow of the wire itself of the string winding material, and thus do not always occur. For this reason, it is difficult to use the bright spot image, which is unstablely generated on the inner surface of the lower portion, for measuring the position, posture, and the like. Therefore, it is necessary to distinguish between the bright spots on the upper outer surface and the bright spots on the lower inner surface to extract only the bright spots on the upper outer surface. In the most general coaxial illumination as shown in FIG. 1, since the binarized bright spot images generated in the upper and lower parts are aligned in a straight line as shown in FIG. 8, the upper part and the lower part cannot be distinguished. Further, when there is a substrate or the like in the back, the specular reflection is directly input, so that it is difficult to separate it from the bright spot image of the coiled wire. By using transmitted illumination, it is possible to obtain a silhouette of a wire rod having a string shape. However, it is difficult to analyze the three-dimensional shape of an object with this silhouette, and it cannot be used when there is a substrate or the like behind it. Oblique illumination may be used because specular reflection from the substrate or the like is not directly input to the imaging means. Known example,
As shown in a pattern detection device (Japanese Patent Laid-Open No. 60-135704), an example is known in which a reflected image from a substrate or the like is removed by performing a logical operation between two systems of binarized images.

[0004]

The following problems have been encountered in measuring the position and orientation of a spirally wound wire rod having a glossy surface.

(1) The specular reflection image from the background of the illumination light and the bright spot image of the wire are separated.

(2) It is determined whether the bright spot image of the coiled wire is the upper outer side or the lower inner side (FIGS. 3 and 4). SUMMARY OF THE INVENTION It is an object of the present invention to provide a string-shaped wire rod position measuring device that solves the above problems and that can measure the position, posture, and overall length.

[0007]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the following structure is adopted.

For example, as shown in FIGS. 3 and 4, an illuminating means for projecting light from four directions so as to be symmetrical with respect to the central axis is provided above the coiled wire rod in the radial direction. Also, these different 4
Image pickup means for individually capturing the optical images of the object obtained by the individual illuminations in the directions and converting them into image signals of four systems, and converting the image signals of four systems output from the image pickup means into binary image signals. A binarization circuit, a binarized image storage circuit for storing a binarized image, and an image logical operation circuit for performing a logical product operation between binary image signals of any two of these four systems, A bright point group recognition circuit for recognizing a plurality of adjacent bright points of the binarized image as one group, and a centroid calculation circuit for measuring the centroid position of each bright point group are provided.

[0009]

As shown in FIG. 5, when oblique illumination is applied to the coiled wire, it occurs on the upper outer surface and the lower inner surface. As shown in FIG. 6, these bright spot images are generated in two rows with the central axis of the coiled wire rod interposed therebetween. At this time, the bright spot images on the upper outer surface are located in the row on the illumination side, and the bright spot images generated on the lower inner surface are located in the row on the opposite side, so that the two can be easily distinguished. .. The bright spot image in the binarized image obtained by the oblique illumination depends on the illumination direction. Bright spot noise caused by factors such as foreign matter also depends on the illumination direction. Therefore, bright spot noise can be generated at different positions by applying oblique illumination from two directions. Therefore, the bright spot noise can be eliminated by performing a logical product operation between the two binarized images.

On the other hand, the bright spot image generated on the wire also depends on the illumination direction, but at the same time, the bright spot image expands due to irregular reflection. For example, as shown in FIG.
From each of the two positions that are offset by deg, give oblique illumination individually,
By performing a logical product operation between the binarized images, a bright spot image can be generated at an intermediate position between these two illuminations.

The bright spots formed by this logical product calculation are processed as a bright spot group, and the center of gravity of each bright spot group on the upper outer surface is calculated. The bright spot thus obtained on the upper outer surface is located on the illumination side with respect to the central axis of the coiled wire as viewed from above. In order to obtain the position of the upper apex on the central axis of the coiled wire, the operations performed so far are performed using two systems of illumination devices on the opposite side symmetrical about the central axis. Then, by comparing the bright point group center of gravity point sequence obtained by the above operation with the bright point group center of gravity point sequence obtained here, the corresponding bright point is examined, and the midpoint thereof is determined to determine the center axis of the coiled wire. You can get the upper vertex coordinate sequence. Further, the total length and posture of the coiled wire can be obtained as shown in FIG. If the diameter D of the wire that constitutes the object is known, the length L of the object is [Equation 1] L = l + D (1 / COSθ2 + 1 / COSθ3) / 2 ≈l + D where l≈ (string winding object The distance between the vertices at both ends on the central axis), θ2, θ3 ≈ 0. Further, the posture of this object can be obtained, for example, from the slope of the regression line of the apex row on the central axis of the object.

[0012]

The present invention will be described in detail with reference to Examples.

FIG. 3 shows an embodiment of the present invention. The present embodiment is an apparatus for measuring the position of an air core coil inserted in a substrate. As shown in FIG. 3, four light guides 3-4 are connected to the light source 4 to divide the light into four systems. The respective lights guided by these light guides 3-4 are condensed by the condenser lens 3-3. The projection light is turned on and off by a shutter composed of a partition plate 3-1 which blocks the tip of the condenser lens 3-3 and an electromagnetic actuator 3-2 which drives the partition plate 3-1. The four illuminations 3a to 3d are projected onto the air-core coil 1 inserted in the substrate 2 from four different directions of the air-core coil radial direction. FIG. 4 is a view of this illumination arrangement viewed from above. In this way, the illumination 3 is arranged so as to be symmetrical with respect to the central axis of the air-core coil.
Arrange a, 3b and 3c, 3d.

By using the image pickup means constituted by the image pickup lens 5 and the video camera 6 and the electromagnetic actuator in conjunction with each other, image signals of four systems by individual illumination in four directions are obtained. This image signal is input to the image processing device 7 and converted into a binarized image signal. Then, the binarized image signal is stored in the image memory in the image processing device 7. The illuminating device is divided into the left and right (FIG. 4, A and B) with respect to the axis of the coil, and the logical product operation is performed between the binarized image data on the same side. In the case of FIG. 4, the illumination systems 3a and 3b (A), the illumination system 3c
And 3d (B), and the result of the binarized image by each of these two sets of light projections is ANDed. An example of this calculation (case A) is shown in FIG. Lighting 3a
The bright spot images 9a and 10a by the
b, 10b can be obtained. The illumination system is set so that there is a portion where 9a and 9b intersect.

The following operation is performed to find the center point of the wire from the bright spot image expanded by diffuse reflection. Since the bright spot images from each direction are expanded and observed due to the influence of diffuse reflection, the portions where the bright spot images are commonly generated by the illumination devices 3a and 3b are near the centers 12A and 13 of the wire. Therefore,
The logical operation result between the binarized images of the illumination devices 3a and 3b is the bright spot images 12A and 13 in FIG. The centroid positions of these bright spots 12A and 13 are calculated to obtain the regression line of the bright spot group, on the other hand, the points on the illumination side are the bright spots on the upper outer surface, and the points on the opposite side are on the lower inner surface. Separate as a sequence of bright spots. The bright spots on the inner surface of the lower part enter the shadow of the wire itself of the coil and do not occur stably. Therefore, in this apparatus, the bright spot 12A on the upper outer surface that is stably obtained is used. Also,
By the above method, the other set of illumination system B also performs the same calculation to obtain the bright spot 12B on the upper outer surface.

The bright spot rows 12A and 12B on the outer surface of the wire thus obtained are arranged symmetrically with respect to the central axis of the air-core coil as shown in FIG. Therefore, 2 obtained above
The upper vertices 18 on the central axis of the coil can be obtained by obtaining the centers of gravity 15 and 16 of the respective bright spots of the two bright spot rows 12A and 12B and calculating the midpoint of the center of gravity of the bright spots on the corresponding wire. .. By this operation, the influence of the specular reflection image from the substrate can be eliminated. Furthermore, it is possible to further reduce the noise generated on the image data. Based on the position of the upper apex 18 on the axes of these coils, the position of the wire rod of the air-core coil and the posture of the coil (θ in FIG. 7).
1) is required. If the wire diameter D of the wire is known in advance, the total length L of the coil is [Equation 2] L = l + D (1 / COSθ2 + 1 / COSθ3) / 2 ≈l + D where l≈ (vertex of both ends on the coil center axis) Distance), θ2, θ3 ≈ 0 (Fig. 7).

[0017]

According to the present invention, it is possible to obtain only the wire rod apex position of the upper part in the radial direction of the coiled wire rod. This makes it possible to determine the total length and posture of the coiled wire.
Also, it is possible to check the number of turns of the air-core coil and measure the gap interval.

[Brief description of drawings]

FIG. 1 is a diagram showing a position where a bright spot image is generated when coaxial illumination is used.

FIG. 2 is a diagram showing a bright spot image generation position when coaxial illumination is used.

FIG. 3 is a diagram showing a configuration example of a coiled wire rod position measuring device.

FIG. 4 is a diagram showing an arrangement of illumination systems viewed from above.

FIG. 5 is a diagram showing a position where a bright spot image is generated when oblique illumination is used.

FIG. 6 is a diagram showing a bright spot image generation position when oblique illumination is used.

FIG. 7 is a diagram showing a generation position of a bright spot image when oblique illumination is applied from two directions in four directions.

FIG. 8 is a diagram showing a method of calculating a posture and a length of a coiled wire.

FIG. 9 is a diagram showing a method of calculating a vertex position on a central axis of a coiled wire.

[Explanation of symbols]

1 ... Wound wire (air core coil), 2 ... Substrate, 3, 3a,
3b, 3c, 3d ... Illumination system, 3-1 ... Partition plate, 3-2 ...
Electromagnetic actuator, 3-3 ... Condensing lens, 3-4 ... Light guide, 4 ... Light source, 5 ... Imaging lens, 6 ... Video camera, 7 ... Image processing device, 8 ... Coaxial illumination, 9 ... Upper part of coiled wire Bright spot image formed on the outer surface, 9a ... Bright spot image formed on the upper outer surface of the coiled wire by the illumination system 3a, 9b
... a bright spot image formed on the upper outer surface of the coiled wire by the illumination system 3b, 10 ... a bright spot image formed on the lower inner surface of the coiled wire, 10a ... on the lower inner surface of the coiled wire by the illumination system 3a Bright spot image that can be formed, 10b ... A bright spot image that is formed on the lower inner surface of the coiled wire by the illumination system 3b, 11 ... A reflection image of the background (substrate), 12A ... Outer upper part of the coiled wire that is formed by the illumination systems 3a and 3b. Logical product calculation result between bright spot images on the side surface, 12B ... Logical product calculation result between bright spot images on the upper outer surface of the coiled wire formed by the illumination systems 3c and 3d, 13A ... Performed by the illumination systems 3a and 3b The result of the logical product operation between the bright spot images on the lower inner surface of the coiled wire, 13
B ... Result of AND operation between the bright spot images on the lower inner surface of the coiled wire formed by the illumination systems 3c and 3d, regression line of the point groups 14 ... 12 and 13 and the bright spot image of 15 ... 12A Center of gravity position, 16 ... Center of gravity position of bright spot image of 12B, 17 ...
The midpoint between the luminescent spot image centroids corresponding to 15 and 16, 18 ...
17 regression lines.

Claims (1)

[Claims] 1. Wires wound in the shape of strings in different radial directions.
Means for illuminating from four directions, imaging means for independently capturing optical images obtained by separately illuminating in four directions, and converting into four-system image signals, and binarizing four-system image signals output from the imaging means A binarization circuit for converting into an image signal, a binarized image storage circuit for storing the binarized image signal, and an image logical operation circuit for performing a logical product operation between the binarized image signals of any two of the four systems. And a bright spot group recognition circuit for recognizing a plurality of adjacent bright spots in the binarized image obtained as a single group, and a gravity center calculation circuit for calculating the gravity center position of each bright spot group. Characteristic winding wire position measuring device.