WO2017204591A1

WO2017204591A1 - Label inspecting device and method

Info

Publication number: WO2017204591A1
Application number: PCT/KR2017/005510
Authority: WO
Inventors: 이은석
Original assignee: 이은석
Priority date: 2016-05-26
Filing date: 2017-05-26
Publication date: 2017-11-30
Also published as: CN109196334A; KR20170133707A; KR101829366B1

Abstract

The present disclosure relates to a label inspecting device for extracting and inspecting a label printed on a specular surface having unevenness, and a label inspecting method using the same. The label inspecting device has a light emitting illuminator arranged at a side of an object having a specular surface on a lower surface thereof, and the illuminator emits the light upward. A light absorbing plate is disposed above the illuminator and absorbs the light emitted from the illuminator. A reflector shade is disposed under the object, and the light, which has not been absorbed by the light absorbing plate, proceeds along a side surface of the object, arrives at the reflector shade, and is reflected by the inner surface of the reflector shade to be projected onto the lower surface of the object. The light, which has arrived at the lower surface of the object, is reflected thereby and is received by a light receiving lens disposed under the reflector shade. An image received by the light receiving lens is sensed by an image sensor disposed under the light receiving lens.

Description

Label inspection device and method

Disclosed herein is a label inspection apparatus for extracting a label printed on the surface of the object as an image and a label inspection method using the same.

Computer vision or machine vision, commonly referred to as contactless visual inspection, is based on the scattering optics of illumination optics. This can be designed and interpreted as Lambert's Law. The surface of an object that satisfies Lambert's law is called the Lambertian Surface, and it is a reflector having a uniform luminous flux in all directions, and means a completely diffused surface having a constant surface regardless of the viewing angle of reflected light. Lambertian surfaces are predictable and analysable.

On the other hand, there is a specular surface that reflects all the light incident on one surface so that the surface is invisible so that information on the surface where the light hits cannot be read. Such specular reflection surface is not suitable for non-contact visual inspection because it cannot get information of reflected light. Thus, inspection and measurement methods for specular reflection surfaces include the measurement of nanoscale microregions using ellipsometry and the microscopic or submicroscale microregions using phase shifting. have.

However, such measurements are routine and do not provide solutions for objects of several millimeters to tens of millimeters in size.

Regarding the appearance inspection of the surface of the specimen as an object, an automatic light control device and a character recognition device of a specimen having the same are disclosed in Korean Patent Laid-Open Publication No. 2002-0051989.

The present invention provides a label inspection apparatus for extracting and inspecting labels, such as patterns and characters, printed on a high glossy / specific surface of an object having a curved specular reflection surface, and a label inspection method using the same.

In addition, the present invention is not limited to the above-described technical problems, and it is apparent that other technical problems may be derived from the following description.

According to one embodiment of the disclosure, the label inspection device is arranged on the side of the object having a specular reflection surface on the lower surface is arranged to emit light, the illumination irradiates the light to the top. The light absorbing plate is provided on the upper portion of the light to absorb light emitted from the light. The reflector is provided under the object, and light that is not absorbed by the light absorbing plate travels along the side surface of the object to reach the reflector, and the light is reflected from the inner surface of the reflector to be projected onto the lower surface of the object. The light reaching the lower surface of the object is reflected and received by the light receiving lens provided under the reflection shade, and the image received by the light receiving lens is detected by the image sensor provided under the light receiving lens.

The label inspection device is characterized by including a lighting controller for adjusting the optimum illumination brightness. And it is characterized in that it further comprises an information processing unit for controlling the operation of the lighting controller, receiving the image detected by the image sensor and inspecting the label printed on the object to detect defects and information.

Here, the light absorbing plate is characterized in that it is composed of one or more of the plate to be absorbed by the melting or matte black paint of the fabric is painted.

The reflector is characterized in that the inner surface is made of a matte white material, such as white acetal, or a workpiece made of a matte white paint so that the diffused reflection of light is well achieved.

According to an exemplary embodiment of the present disclosure, by removing the specular reflection information from the object, it is possible to secure high quality image information to increase the recognition efficiency of a label such as a character printed on a curved surface and to effectively detect printing defects of the label. .

1 is a block diagram of a label inspection apparatus according to an embodiment of the present disclosure.

2 is a flowchart illustrating a method of inspecting printed matter according to an embodiment of the present disclosure.

3 is a conceptual diagram representing that the angle of reflection varies according to the surface to which light is irradiated.

4 is a conceptual diagram modeling the bottom shape of a typical plastic injection molding.

5 is a typical image in which specular reflections are photographed.

FIG. 6 is an image from which the specular reflection ray photographed using the label inspection apparatus according to an exemplary embodiment of the present disclosure is removed.

Hereinafter, a label inspection apparatus and a label inspection method using the same according to a preferred embodiment with reference to the accompanying drawings in detail as follows. In the following description of the contents disclosed herein, if it is determined that detailed descriptions of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the contents disclosed herein, and may vary according to intention or precedent of a user or an operator, and accordingly, the meaning of each term is based on the contents throughout the specification. It should be interpreted. For reference, in the drawings, each component is omitted or schematically illustrated for convenience and clarity, and the size of each component does not reflect the actual size. In addition, the same reference numerals throughout the specification refer to the same components and reference numerals for the same components in the individual drawings may be omitted.

An embodiment of the present disclosure is to extract an image for inspecting a label such as a pattern or a character printed on a surface of a concave high-gloss material in which diffuse reflection or specular reflection may occur, and light scattered using a reflection shade The present invention relates to a label inspection apparatus and method for illuminating a surface of an object and effectively blocking specular light incident from a curved surface.

1 is a block diagram of an apparatus for inspecting a label according to an exemplary embodiment of the disclosure.

Label inspection apparatus 1 according to an embodiment includes an illumination 20, a light absorbing plate 30, a reflection shade 40, a light receiving lens 50, the image sensor 60.

The object 10 is a specimen in which a label to be inspected is printed by a label inspection apparatus according to the disclosed contents. The lower part of the object 10 has a curved specular reflection surface, and a label containing information such as letters and patterns is printed on the lower surface of the object 10 having the specular reflection surface. In order to manage and inspect the object 10, information such as a serial number and a manufacturing date must be managed. For this purpose, a technology of recognizing an image printed on the object 10 and processing an image to extract a label containing such information is required. Do.

First, the illumination 20 is an element that provides a light source around the object 10 to inspect a label printed on the object 10. The vertical portion of the illumination 20 is provided with a light absorbing plate 30 for suppressing the absorption and reflection of light. The light absorbing plate 30 may be composed of a plate having a surface made of a melted or matte black workpiece of the fabric, and suppresses the incident light to be reflected again. The light irradiated from the illumination 20 is emitted toward the light absorbing plate placed on the vertical top of the illumination. LEDs may be used as the illumination 20, and the illumination 20 is preferably directed upward only toward the light absorbing plate. To this end, the lamp shade 22 is provided at the bottom of the light to prevent the light from being directly emitted to the lower part of the object 10.

The lower portion of the object 10 is provided with a reflection shade 40 having an inverted truncated cone shape, the upper portion of which is wider than the lower surface of the object 10 and narrowed toward the lower portion. Light rays starting from the illumination 20 are diffused and diffused toward the light absorbing plate 30, while some light is impinged on the surface of the object 10 to be diffracted and refracted. Such light is incident on the inner surface of the reflector 40 along the surface of the object 10. Some of the light incident on the reflection shade 40 is hit by the inner surface of the reflection shade 40 again to be reflected and projected to the lower portion of the object 10. To this end, the reflection shade 40 is made of a matte white material workpiece, such as white acetal, or a matte white paint is made of a workpiece that is well diffused reflection of light. Although the reflector 40 is illustrated and described in the shape of a truncated cone, the present invention is not limited thereto. When the light diffracted and refracted by the object in the illumination is incident into the reflector, the reflector 40 may reach the lower surface of the object above the reflector. As long as the shape is sufficient, it can be modified and applied in various shapes. For example, although not shown, the upper portion may be disposed outside the object, and may be configured to be separated into a plurality of surfaces inclined at an angle at which incident light may be reflected to the lower surface of the object on the upper side of the reflector. .

An image sensor 60 is provided below the reflection shade 40, and a light receiving lens 50 is disposed between the reflection shade 40 and the image sensor 60. Some of the light rays emitted from the illumination 20 hit the object 10 to be diffracted and refracted to enter the reflector 40 along the surface of the object 10, and a part of the light is reflected by the reflector 40 again to reflect the object ( After reaching the lower surface of 10), the light is reflected again and the light receiving lens 50 receives the light and transmits it to the image sensor 60.

The image sensor 60 detects the image received by the light receiving lens 50 and transmits the image to the information processor 80.

On the other hand, the lighting 20 may be controlled by the light controller 70 on / off and the brightness of the light. Therefore, the brightness of the light emitted from the light 20 may be controlled by controlling the light controller 70 so that the optimal image is detected by the image sensor 60. The lighting controller 70 may be controlled manually or the operation may be controlled by the information processor 80.

The information processor 80 controls the operation of the lighting controller 70. In addition, the image sensed by the image sensor 60 is received to recognize a label printed on the object 10.

In this case, white light may be used for the illumination 20 to obtain a clear label image regardless of the color of the object 10. Through this, the image sensor 60 may use an image obtained by photographing a color image. The information processor 80 extracts the background color of the object 10, that is, the color information of the object 10, from the captured color image. When the background color is confirmed, the label printed in another color contrasted with the background color processes the color image so that the contrast ratio can be compared with the background color. The corrected color image extracts a clearer label image and inspects the printed label.

When the label inspection apparatus according to the above embodiment is used, a clear label image may be extracted by removing the specular reflection occurring at the curved lower surface when inspecting a label printed on the curved surface on the lower surface of the object 10.

2 is a flowchart illustrating a label inspection method using a label inspection apparatus according to an exemplary embodiment of the present disclosure.

First, the object 10 is positioned on the label inspection device. The object 10 has a curved surface on its lower surface, and a label such as a letter is printed thereon. The illumination 20 is arranged on the side of the object 10, and the light absorbing plate 30 is provided on the illumination 20. Illumination 20 may be made of a white light source, the illumination 20 is irradiated toward the light absorbing plate 30 (S10).

Some light that is not absorbed by the light absorbing plate 30 is incident to the reflection shade 40 provided below the object 10 along the side surface of the object 10. The light incident on the reflection shade 40 is reflected on the inner surface of the reflection shade 40 and is projected onto the bottom surface of the object 10 (S20).

The light projected on the lower surface of the object 10 is reflected again to reach the image sensor 60 by the light receiving lens 50 provided under the reflector 40 to take an image (S30). In this case, the image sensor 60 may acquire a color image by the white light illumination 20.

The background color of the object 10 is checked by processing the color image photographed by the image sensor 60 (S40).

In operation S40, the color image is processed to contrast the background color and the contrast ratio of the label printed in a color different from that of the object 10, that is, the background color. In the processed color image, the label may be more clearly extracted, and thus, the label image displayed on the bottom surface of the object 10 is extracted (S50). As a result, inspection information may be obtained from the extracted label image to manage and inspect the object.

As such, one embodiment disclosed herein is to reflect the scattered light on the surface of the specular reflection using a reflection shade and to generate an image from which the specular reflection is removed to effectively inspect the printed label.

On the other hand, Figure 3 is a conceptual diagram representing that the angle of reflection changes depending on the surface to which light is irradiated, and shows the shape of the reflective surface and the movement path of the light. Circular reflectors reflect light uniformly and are condensed, scattered and scattered inside the circle. On the other hand, in the case of a parabolic reflecting surface, light is reflected parallel to the geometric axis of the reflecting surface, and the elliptical reflecting surface is uniformly diffusely reflected, so that it is focused, scattered, and scattered outside of the circle.

Figure 4 is a conceptual diagram modeling the shape of the bottom surface (lower surface) in a typical plastic injection container or glass bottle. It can be seen that it is made in a concave shape to withstand the pressure in the container, this shape is very similar to the shape of a circular to parabolic or oval. In addition, in the case of a plastic injection molding, the casting hole of the mold is located at the center of the shape, and thus the shape of the double shape is obtained.

In the case of the above-mentioned shape, the depth of the surface was deepened, so that the label printed on the lower surface of the object could not be clearly photographed beyond the depth of the light receiving lens. Labels were taken with the camera and added to the difficulty. This can be seen in FIG. 5, which is a typical image of specularly reflected light.

Disclosed herein is to reflect the scattered light on the printed label using a reflector, to obtain an image from which the specular light is removed to effectively inspect the label printed on the specular surface.

FIG. 6 is an image from which the specular reflection ray photographed using the label inspection apparatus according to an exemplary embodiment of the present disclosure is removed. Compared with the image of FIG. 5, it is confirmed that the printed label is white and difficult to be recognized due to the specular reflection on the curved surface, so that the specular reflection is removed to clearly recognize the label.

As described above, the contents disclosed in the present specification allow the scattered light to strike the surface of the object so as to block the specular reflection incident from the concave curved surface, so that the reflector is not condensed by the surface shape to create an uneven image that appears. By changing the curvature and height of the, you can effectively inspect the printed labels.

Although the embodiments have been described in detail with reference to the accompanying drawings, the contents disclosed herein are not necessarily limited to the embodiments, and various modifications can be made without departing from the technical spirit of the disclosed contents. . Therefore, the embodiments disclosed in the present specification are not intended to limit the technical spirit of the disclosed contents, but are intended to describe the scope of the technical spirit of the disclosed contents by the embodiments. The scope of protection of the disclosed contents should be interpreted by the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the rights of the disclosed contents.

** Description of the sign **

10: object

20: lighting

22: lampshade

30: light absorbing plate

40: reflection shade

50: light receiving lens

60: image sensor

70: lighting controller

80: information processing unit

Claims

An illumination 20 arranged on the side of the object 10 labeled on the bottom surface having a curved surface, the illumination 20 emitting light upwards;

A light absorbing plate 30 disposed above the lighting 20 and absorbing light emitted from the lighting 20;

At least one reflector provided under the object 10 and not being absorbed by the light absorbing plate 30, and incident light along the side surface of the object 10 is reflected to be projected onto the bottom surface of the object 10. 40;

A light receiving lens 50 provided below the reflection shade 40 and receiving light reflected from a bottom surface of the object 10; And

And an image sensor (60) provided below the light receiving lens (50) to sense an image received by the light receiving lens (50).
The method of claim 1,

The lighting device 20 is a label inspection device, characterized in that it further comprises a lighting shade (22) to prevent light from being directly emitted to the reflecting shade (40).
The method of claim 1,

The reflection shade 40 is a label inspection device, characterized in that it has an inverted truncated cone shape.
The method of claim 1,

The reflection shade 40 is a label inspection device, characterized in that the inner surface is made of a matte white material workpiece.
The method of claim 1,

Label inspection apparatus further comprises a lighting controller (70) for controlling the brightness of the illumination (20).
The method of claim 1,

And an information processor (80) for detecting defects and information by recognizing a label displayed on the lower surface of the object (10) by receiving the image sensed by the image sensor (60).
The method of claim 1,

The light absorbing plate 30 is a label inspection device, characterized in that the plate having a surface made of a melted or matte black workpiece of the fabric.
Irradiating the light (20) arranged on the side of the object (10) labeled on the lower surface having a curved surface with a light absorbing plate (30) provided on the light (20) (S10);

Light that is not absorbed by the light absorbing plate 30 is incident on the reflector 40 provided below the object 10 along the side surface of the object 10, and the light incident on the reflector 40 is incident. Reflecting and projecting the bottom surface of the object (S20) (S20);

And reflecting the light projected on the lower surface of the object (10) to reach the image sensor (60) provided at the lower portion of the reflection shade (40) (S30); label inspection method comprising a.
The method of claim 8,

The illumination 20 is white light,

The image sensor 60 captures a color image,

And (S40) checking the background color of the object (10) in the color image obtained after the photographing step (S30).
The method of claim 9,

In step S40, the background color is checked, and a label printed on the bottom surface of the object 10 is processed by processing the color image such that a label printed in a color different from the background color is contrasted with a background color. The label inspection method further comprises the step of extracting an image (S50).