KR100889005B1 - Image measuring system and method of inspecting goods using same - Google Patents

Abstract

According to the present invention, an image of a three-dimensional object can be obtained by irradiating a surface of a rotating object with a slit-shaped laser, and it is possible to determine whether the object is defective using the acquired image. To that system and method.

An image measuring system according to the present invention includes an object rotated by a motor means for generating a rotation force; A laser diode to which a slit-shaped laser light is irradiated onto the object; A camera for receiving a laser light in a slit form irradiated onto the object; An image processor which receives light received through the camera and converts the received light into an image; A reference image DB in which a reference image corresponding to the object is stored; And a microcomputer that determines whether there is a defect in the target object by comparing the acquired image acquired by the image processor with the reference image, and wherein the image processor sequentially processes the fragment images obtained as the target object is rotated. Arranging the acquired image by arranging.

Description

An image measurement system and method for inspecting an object by using the system}

According to the present invention, an image of a three-dimensional object can be obtained by irradiating a surface of a rotating object with a slit-shaped laser, and it is possible to determine whether the object is defective using the acquired image. System and method.

A general vision processing system refers to a system for processing a desired image by applying various algorithms to an image obtained by capturing an image input from a camera from a grabber board.

In addition, a 3D image may be obtained and processed when it is difficult to obtain an accurate image with a 2D image system.

In the general vision system, an image is acquired by using a camera, the acquired image is saved by an image processing apparatus (PC, etc.), the image is processed by the image processing apparatus, and the result is displayed on a monitor (PLC). Correct the wrong part by using the controller).

Such a vision system does not have high reliability in judging three-dimensional shape. Even a simple flat part may have a poor inspection quality depending on the ambient light or camera condition. And the quality of inspection becomes worse due to the shadow problem caused by the bending of the part.

Therefore, in order to obtain more accurate results, it is necessary to obtain accurate three-dimensional image data using an expensive three-dimensional laser scanner and analyze it. In this case, the cost of purchasing an expensive laser scanner increases, and in three dimensions It takes too much time to process the data of the made image.

1 is a schematic configuration diagram of a conventional three-dimensional image measurement system.

The conventional 3D image measuring system includes a light emitting unit 110 for projecting ray light toward an object object 105 and a light emitting unit 110 accommodated in a predetermined housing 106 together with the light emitting unit 110. A CCD camera 120 for generating an image signal of the laser light projected from the object object 105 and interposed between the object object 105 and the CCD camera 120 to selectively pass the laser light of a specific band. And a three-dimensional image generator 132 for generating a three-dimensional image of the target object 105 from the image signal of the laser beam generated by the CCD camera 120.

The light emitting unit 110 has a laser diode 112 for emitting a laser light, and a driving voltage supply unit 116 for supplying a driving voltage to the laser diode 112, and the driving voltage supply unit 116 is a single unit. Generates a driving voltage and supplies it to the laser diode 112.

The CCD camera 120 receives the light reflected from the target object 105 and image-processes the image to generate an image signal of the laser beam.

The CCD camera 120 includes a camera lens 124 for guiding the laser beam passing through the band pass filter 107 and an AD converter for converting the laser image signal passing through the camera lens 124 into a digital laser image signal. And an image processor 129 for generating image data of the laser beam from the digital laser image signal converted by the AD converter 128 and storing the image data of the laser beam in a predetermined memory.

In this case, the image data of each laser beam generated by the image processor 129 includes optical noise generated by the charge coupling device 126 as well as ambient optical noise.

The relative position of the camera lens 124 with respect to the object object 105 is adjusted stepwise by the position adjusting unit 140, for this purpose, the position adjusting unit 140 is a table 142 for mounting the object object 105 And a mechanical drive system 144 for moving the table 142 on the same plane.

The displacement sensor may be mounted on the mechanical driving system 144 to obtain movement information of a relative position of the camera lens 124 with respect to the object object 105.

The image data of the laser light generated by the CCD camera 120 may be used to generate a 3D surface image of the object 105 together with the position control information of the position adjusting unit 140. 132 is provided.

However, according to the conventional three-dimensional image measuring system using a laser beam, three-dimensional representation of the object may be possible than the apparatus for processing the image in two dimensions, but as described above, a lot of data processing is required. However, there is still a difficult problem in acquiring accurate image information due to the distance from the illumination and the shadow of the object.

The present invention is proposed to solve the above problems, using a slit-shaped laser beam image measuring system that can improve the distortion of the object due to the shadow of the illumination and other image processing calculation and the use of the same It is an object to propose a method for inspecting an article.

An image measuring system according to the present invention includes an object rotated by a motor means for generating a rotation force; A laser diode to which a slit-shaped laser light is irradiated onto the object; A camera for receiving a laser light in a slit form irradiated onto the object; An image processor which receives light received through the camera and converts the received light into an image; A reference image DB in which a reference image corresponding to the object is stored; And a microcomputer that determines whether there is a defect in the target object by comparing the acquired image acquired by the image processor with the reference image, and wherein the image processor sequentially processes the fragment images obtained as the target object is rotated. Arranging the acquired image by arranging.

According to another aspect of the present invention, a method for inspecting an article includes: irradiating a slit-shaped laser light to the target object to determine whether there is a defect in the appearance of the object; When the object is rotated by a motor means having a rotational force, obtaining a plurality of slit-shaped pieces of images by receiving a laser light of a slit type irradiated at a predetermined time and converting the image into a image; Forming an acquired image of the object by sequentially arranging the obtained slit-shaped pieces of images; And determining whether the acquired image is identical to the previously stored reference image, and determining whether the target object is defective.

According to the proposed embodiment of the present invention, it is possible to extract feature points of a great variety of surface shapes according to the shape of each object, and it is possible to determine whether the desired object is precisely damaged by simple processing instead of a complicated algorithm. have.

In addition, in the case of the shape of a specific pattern, it is possible to have a fast image processing ability because it is possible to immediately determine whether a part is defective by using only one cut image represented by a simple line without obtaining an entire stereoscopic image. There is an advantage that can be distributed processing.

Hereinafter, with reference to the accompanying drawings for the present embodiment will be described in detail. However, the scope of the idea of the present invention may be determined from the matters disclosed by the present embodiment, and the idea of the invention of the present embodiment may be performed by adding, deleting, or modifying components to the proposed embodiment. It will be said to include variations.

In the following description, the word 'comprising' does not exclude the presence of other elements or steps than those listed.

However, in the following description of the embodiment of the present invention, a detailed description of the known technology will be omitted, and the configuration and operation of the technical features of the present invention will be described.

2 is a diagram illustrating an image measuring system according to an exemplary embodiment of the present invention.

According to an embodiment of the present invention, the laser diode 230 for emitting the laser light in a slit form, the determination of the amount of light of the laser diode 230 and the laser control for supplying power to the laser diode 230 The unit 220 and the target object 250 rotated by the motor driving unit 240.

Here, the laser diode 230 is disclosed as a configuration for emitting a laser light in the slit type, but is not necessarily a laser light, and may be a light source capable of emitting light in a slit shape while having a straightness.

In particular, the target object 250 is rotated by the rotational force generated by the motor driving unit 240, irradiated to the surface of the target object 250, the laser light of the slit type emitted from the laser diode 230 is rotated As a result, a scanning operation on the surface of the object 250 is started.

The object 250 may have any shape as long as the object can be irradiated to the outer circumferential surface of the slit-shaped laser light, but in the embodiment of the present invention, the outer circumferential surface has a cylindrical shape having a constant shape by rotation by a motor. Illustrated as an article.

The laser light emitted from the laser diode 230 is provided in a slit form, and the laser light emitted from the laser diode 230 is separated between the laser diode 230 and the target object 250 so that external noise is not included. It may further include a cylindrical lens for converting to a linear slit.

The slit-shaped laser light emitted from the laser diode 230 is irradiated to the surface of the outer circumferential surface of the object 250 with the slit beam 251, and the camera 260 receives the slit beam 251.

The slit beam received by the camera 260 includes information on the outline of a portion (slit shape) of the outer circumferential surface of the object object 250, and the received slit beam is converted into a digital image by the image processor 270. Processed, the camera 260 may be a CCD camera as in the prior art.

In addition, the image processing unit includes a converter and a filter for converting an analog signal into a digital signal, and the detailed configuration of the image processing unit may be implemented by the prior art, and thus a detailed description thereof will be omitted.

Here, the object 250 is rotated at a constant speed as the motor driver 240 is driven, the laser light of the slit type emitted from the laser diode 230 is sequentially irradiated on the outer peripheral surface of the object do.

In addition, the camera 260 sequentially receives a laser beam irradiated on the outer circumferential surface of the object object 250, so that the slit beam processed by the image processor 270 is an outer circumferential surface of the object object 250. Becomes a flat piece for.

Next, the image processing unit 270 sequentially obtains pieces of information about the outer circumferential surface of the target object 250, that is, slit images of the outer circumferential surface of the target object 250, thereby obtaining an acquired image (plane image). It becomes possible.

The acquired image (or planar image) acquired by the image processor 270 is transferred to the microcomputer 210, and the microcomputer 210 compares with the previously stored reference image according to whether the acquired image matches. It is determined whether the target object 250 is defective.

In detail, a reference image DB 280 is provided which stores reference images of target objects for determining whether an item is defective, and the microcomputer 210 is stored in the reference image DB 280. A comparison is made with a reference image (a two-dimensional image formed by arranging a plurality of slit images) to determine whether or not a match is greater than or equal to a predetermined value.

The reference image DB 280 stores a reference image of an article to be inspected by an administrator (or user) of the system, and the reference images may be a planar image in which image pieces in a slit form are arranged.

Referring to FIGS. 3 and 4, a process of image processing a slit beam irradiated to an object according to an embodiment of the present invention will be described. FIG. 3 provides an object in a cylinder, and FIG. 4 shows an outer circumferential surface of the cylinder. A curved object is provided.

Referring to FIG. 3, the slit-shaped laser light emitted from the laser diode is irradiated to the object as shown in (a), and the camera receiving the slit light irradiated to the object is as shown in (b). A beam of shape is received.

The image processing apparatus connected to the camera performs image processing on the light having the shape as shown in (b), and sequentially receives the plurality of slit-shaped laser lights irradiated as the object is rotated through the camera, thereby eventually processing the image. The image processed by the apparatus is shown in (c).

That is, the image processing apparatus sequentially arranges pieces of images obtained by the slit-shaped laser light, thereby obtaining a planar acquired image as shown in (c).

Here, the microcomputer 210 determines whether the image acquired as shown in (c) and the reference image stored in the reference image DB 280 match each other, and the two images do not deviate from a preset error range. In this case, the object shown in (a) is regarded as a defect-free article.

In FIG. 4, the object is curved in a predetermined number of times on the outer circumferential surface, but in this case, the image processing unit 270 acquires a single image by arranging slit-shaped pieces of images sequentially received. In operation 210, the reference image related to the object is read from the reference image DB 280, and then the defect image of the object is determined.

In summary, when the laser light in the slit form is irradiated to the target object to determine whether there is a defect through the laser diode and the laser control device, the camera receives the laser light irradiated onto the object and processes the image into a slit. It will appear as a piece of image.

Therefore, when the object is rotated by the motor driving unit, a plurality of slit-shaped pieces of images obtained through the camera and the image processing apparatus are arranged, and when the objects are arranged in sequence, as shown in FIGS. 3 and 4 (c). The image as shown is displayed.

In addition, the microcomputer determines the correspondence of the acquired image using the reference image of the corresponding object stored in advance.

5 is a flowchart illustrating an article inspection method according to an embodiment of the present invention.

As a method for determining whether there is a defect in the appearance of the manufactured article, the object is irradiated with a laser light in the form of a slit (S101).

Then, the irradiated laser light is received and processed into an image, thereby processing into a slit-shaped piece image (S102).

When the object is rotated about one axis by a predetermined motor, the slit-shaped laser light is moved along the outer circumferential surface of the object, and receives and image the slit light irradiated at a predetermined time. By processing, a plurality of slit-shaped pieces of images are obtained.

In addition, the planar images of the target object are acquired by sequentially arranging the obtained slit-shaped pieces of images (S103), wherein the planar image is not necessarily a two-dimensional image but a slit unit of the outer circumferential surface of the target object. It is to be understood that the expression is successive.

Then, it is determined whether the plane image (acquired image) acquired for the object and the reference image for the corresponding object stored in advance are matched, and when the correspondence falls within the preset error range, It is determined that there is no defect in the appearance (S104).

If the correspondence between the acquired image and the reference image is outside the preset error range, it is determined that there is a defect in the appearance of the manufactured object and the user or manager is notified.

When the image is processed using only the surface shape that appears, a simple 3D scanner and a stereoscopic shape different from each other can be expressed, and the three-dimensional image of the surface is much different from the image obtained from a simple camera or a stereoscopic image obtained by using the 3D scanner. .

That is, according to an embodiment of the present invention, by rotating the object necessary to determine all the objects having a general three-dimensional sense, only a three-dimensional appearance of a simple surface can be obtained and the shape of the object can be determined using the same.

In this process, the feature points of a large variety of surface shapes can be extracted according to the shape of each object, and it is possible to determine whether the desired object is precisely damaged by simple processing instead of a complicated algorithm.

In particular, in the case of the shape of a specific pattern, it is possible to have a fast image processing capability because it is possible to immediately determine whether a part is defective by using only one cut image represented by a simple line, without obtaining an entire stereoscopic image. Can be distributedly processed.

In addition, although the accuracy of conventional image processing is related to the resolution of a sensor possessed by a camera, in the present embodiment, the actual precision is correlated with the fineness of the linear illumination (line laser) and the number of screens of an image that can be obtained during one revolution. There is this. In other words, by using a thin laser beam and how many images are acquired in one rotation, a precise density image image of the surface of the object can be obtained.

1 is a schematic configuration diagram of a conventional three-dimensional image measurement system.

2 is a view for explaining an image measuring system according to an embodiment of the present invention.

3 and 4 are views for explaining a process of image processing the slit beam irradiated to the object in accordance with an embodiment of the present invention.

5 is a flow chart for explaining the article inspection method according to an embodiment of the present invention.

Claims (5)

Motor means for generating a rotational force; A laser diode for irradiating a laser light having a slit shape to the object rotated by the motor means; A camera for receiving a laser light in a slit form irradiated onto the object; An image processor which receives light received through the camera and converts the received light into an image; A reference image DB in which a reference image corresponding to the object is stored; And And a microcomputer that determines whether the target object is defective by comparing the acquired image acquired by the image processor with the reference image. And the image processing unit acquires the acquired image by sequentially arranging pieces of images acquired as the object is rotated. The method of claim 1, The microcomputer determines whether the acquired image is identical to the reference image, and if the two images coincide with each other without departing from a preset error range, the microcomputer determines that the target object is free of defects. delete As a method for determining whether there is a defect in the appearance of the object, Slit-type laser light is irradiated onto the object; When the object is rotated by a motor means having a rotational force, obtaining a plurality of slit-shaped pieces of images by receiving a laser light of a slit-type irradiated every predetermined time and converting the laser light into an image; Forming an acquired image of the object by sequentially arranging the obtained slit-shaped pieces of images; And And determining whether there is a defect in the target object by determining whether the acquired image matches a previously stored reference image. The method of claim 4, wherein The determining of whether the target object is defective may include determining that the target object is free of defects when the two images coincide to the extent that the acquired image and the reference image do not deviate from a preset error range. Article inspection method.

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