JP2635890B2 - Distance measurement method by image processing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distance measuring method by image processing. In particular, when cutting and removing the lap wound yarn (thread lap winding portion) generated when a transfer tail is formed at the end of a bobbin (especially a paper tube), the distance by which the cutting device is moved is measured by an image measuring device. More specifically, the present invention relates to a method for measuring the distance for moving a cutting device for cutting lap wound yarns at the bobbin end of a cheese or a yarn made of synthetic fibers such as polyester or polyamide fibers. About.

[0002]

2. Description of the Related Art In recent years, when a synthetic fiber yarn such as polyester or polyamide fiber is processed by a draw twisting machine, a draw false twisting machine, or the like, a yarn end at a start of winding between yarn bobbins and a yarn end at an end of winding. A so-called transfer tail is formed at the end of the bobbin outside the traverse area at the beginning of winding in order to perform continuous processing by combining the above-mentioned methods (Japanese Patent Publication No. 57-36233, 58-19555
No. 3).

[0003] The yarn package thus wound up
To facilitate transfer tail processing,
After removing the bunch winding (lap winding) or pigtail formed at the bobbin end while leaving the transfer tail of a certain length, the end of the yarn is a tape, label, seal (paper). ) Is fixed to the bobbin end.

Conventionally, the stripping process of such a thread-wound portion has been manually performed. However, in recent years, mechanization and automation have been attempted, and a method disclosed in Japanese Patent Application Laid-Open No. 2-43180 has been proposed. As a method for detecting the cutting position of the lap winding for this purpose, near-ultraviolet light is applied to the lap winding portion, the secondary excitation light from the yarn is detected by a solid-state camera, and the position of the lap winding is measured. I do.

[0005]

However, in order to avoid the bulging of the end face of the thread package called a bulge, it is necessary to attach the solid camera with a fixed angle between the solid camera and the normal direction of the paper tube. The distance between the end of the bobbin and the solid-state camera is different depending on the position on the bobbin, and the difference in the distance is beyond the depth of field of the solid-state camera. A defocus occurs in a part of the image at the position. Due to this defocus, the image is blurred, and the position where the amount of reflected light exceeds the threshold value cannot be specified. For this reason, there has been a problem that a measurement error of the distance on the bobbin by image measurement occurs, the measurement accuracy is deteriorated, and sufficient detection accuracy of the transfer tail which must not be cut cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and occurs when a part of an object to be measured or a measurement reference position is located outside a depth-of-field range of an image processing camera due to a defocus of the camera. An object of the present invention is to easily improve deterioration of measurement accuracy due to a measurement error.

[0007]

SUMMARY OF THE INVENTION A distance measuring method by image processing according to the present invention is a method of measuring a distance on a surface to be measured because an image processing camera has an arbitrary mounting angle with respect to a normal direction of the surface to be measured. When measuring the distance from the reference position to the object to be measured when the set reference position or a part of the object to be measured exists outside the depth of field range of the camera, the object to be measured is The focus of the camera is set so as to be located within the depth of field range, the reference position is virtually set in the image processing controller, and an object to be measured corresponding to the reference position is set. Marking press that keeps the brightness level of the reflected light amount constant at the position
The measurement error due to the defocus of the camera, which is generated in the vicinity of the object to be measured or in the vicinity of the reference position, is provided.

That is, the present invention provides an image processing camera for measuring the distance between a lap portion or a transfer tail portion of a yarn package and a reference position, and an image processing apparatus for virtually setting the reference position. And a marking plate for maintaining a constant light and dark level near a position on the yarn package corresponding to the reference position, and a measurement accuracy caused by a measurement error of the distance caused by a defocus of the camera. This is a distance measuring method by image processing, which is characterized by improving deterioration of the distance.

Here, when the reference position or a part of the object to be measured exists outside the depth-of-field range of the camera, the reference position is outside the depth of field and the object to be measured is the depth of field. Or the reference position is within the depth of field and a part of the object to be measured is outside the depth of field.

In addition, since a commercially available image processing controller can be used for the distance measurement of the present invention, if the focus shift caused by the reference position or the object to be measured being outside the depth of field is eliminated, the distance to be measured can be reduced. The distance can be measured by removing a measurement error due to a focus shift of the camera occurring near the target or near the reference position.

The distance from the reference position to the object to be measured is measured by focusing on the difference in the amount of reflected light between the object to be measured (such as a thread) and the background (such as a paper tube), and a predetermined threshold is set. The measurement is performed by measuring the distance between the light receiving position of the reflected light amount equal to or more than the value and the reference position.

By the way, the light / dark level of the marking plate is bright above the threshold value and dark below the threshold value. The threshold value is twice or more the maximum value of the reflected light amount of the background (paper tube, etc.). Is preferred.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a distance measuring method by image processing according to the present invention. In order to avoid the bulge 1 on the end face of the yarn package, an arbitrary angle 2 from the normal direction of the paper tube 7 of the package is used.
Paper core 7 by the image processing camera 3 attached with
In order to cut the overlapped yarn 4 existing at an arbitrary position in the measurement range 5 of the camera 3 above, the overlapped yarn 4 which is a moving distance 6 of the cutting device and the end face of the paper tube are set. The distance from the measurement reference position is measured. In measuring the moving distance 6, the thickness of the paper tube 7 and the depth-of-field range 8 of the camera 3 are taken into consideration, and the moving distance is virtually determined by software processing inside the image processing controller 11. In order to maintain the measurement reference position of the reference position 6 and keep the light / dark level of the reference position constant, the marking plate 9 is placed near the position 10 on the bobbin corresponding to the reference position, and the yarn corresponding to the reference position. After arranging the package so that the position on the package is on the marking plate, image processing is performed so that the measurement reference position is set to the depth of field 8 of the image processing camera 3.
Outside, and the lap winding yarn 4 is located in the depth of field range 8
Deterioration of measurement accuracy due to a measurement error due to a focus shift generated when the camera is located inside the camera can be easily improved.

[0014]

According to the present invention, when a part of the object to be measured or the measurement reference position is located outside the depth-of-field range of the image processing camera, the accuracy of the measurement due to the measurement error caused by the defocus of the camera is reduced. Deterioration can be easily improved.

In particular, in order to automate the stripping of the wrapped portion and the pigtail portion of the thread wound material, image processing is performed on the wrapped portion or the transfer tail portion of the yarn on the bobbin which is the surface to be measured. When measuring the moving distance of the cutting device for cutting the overlapped yarn in a state where the distance from the camera for fixing is fixed at an arbitrary angle existing beyond the depth of field range of the camera. In addition, it is possible to improve the measurement accuracy deteriorated due to the measurement error of the moving distance caused by the defocus of the camera.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a distance measuring method by image processing according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 bulge of yarn package end face 2 Normal line of paper tube and angle of image processing camera 3 Image processing camera 4 Overlapping yarn 5 Measurement range of image processing camera 6 Moving distance 7 Paper tube 8 Image processing Depth of field range of camera 9 Marking plate 10 Position on paper tube corresponding to measurement reference position 11 Image processing controller

Claims (1)

(57) [Claims] An image processing camera has an arbitrary mounting angle with respect to a normal direction of a surface to be measured, so that a reference position set on the surface to be measured or a part of the object to be measured is not covered by the camera. When measuring the distance from the reference position to the object to be measured when present outside the depth of field range, focus the camera so that the object to be measured is located within the depth of field range of the camera. And setting the reference position virtually in the image processing controller.
By providing a marking plate at the position of the object to be measured corresponding to the reference position to make the light / dark level of the amount of reflected light constant, the focus shift caused by the camera near the object to be measured or near the reference position. A distance measuring method by image processing, wherein a measuring error is removed.