WO2012134146A1

WO2012134146A1 - Apparatus for inspecting vision using stereo vision and lattice pattern

Info

Publication number: WO2012134146A1
Application number: PCT/KR2012/002219
Authority: WO
Inventors: 박찬화; 김성현; 구자명
Original assignee: 주식회사 미르기술
Priority date: 2011-03-31
Filing date: 2012-03-27
Publication date: 2012-10-04
Also published as: KR20120111196A; KR101245622B1

Abstract

An apparatus for inspecting vision, according to the present invention, is for photographing with a camera an inspection object, which is assembled or mounted in a parts assembly process, and then comparing the photographed image with an object image that is inputted in advance to determine whether the inspection object is satisfactory or defective, and comprises: a stage portion for fixing or transferring the inspection object to an inspection position; a lighting portion, which is positioned on the upper portion of the stage portion, for providing light on the inspection object; a central camera portion, which is positioned at the center of the lighting portion, for obtaining a two-dimensional shape of the inspection object; side camera portions which are arranged in a plurality on the side portion of the central camera portion; a plurality of lattice pattern irradiation portions, which are arranged on the side portion of the central camera portion, between the cameras in the side camera portion; a vision processing portion for reading the image that is photographed by the central camera portion to determine whether the inspection object is satisfactory or defective; and a control portion for controlling the stage portion, the lattice pattern irradiation portion, and the camera portion, wherein two predetermined cameras from the side camera portions photographs the inspection object for measuring the height of the inspection object, and wherein one of the lattice pattern irradiation units irradiates a lattice pattern for measuring the height.

Description

Vision Inspection System Using Stereo Vision and Plaid

The present invention relates to a vision inspection apparatus, and more particularly, by performing a vision inspection using a plaid together with a stereo vision, the vision using a stereo vision and a plaid that can quickly and accurately measure the height of the inspection object It relates to an inspection apparatus.

In general, Surface Mounting Technology (SMT) for assembling surface-mounted components to a printed circuit board (PCB) or the like is a technique for miniaturizing / integrating surface-mounting components (SMD) and such surface-mounted components. Development of precision assembly equipment for precise assembly and technology for operating various assembly equipment.

Surface mount lines consist of equipment such as surface mounters and vision inspection equipment. The surface mounter is a device for mounting surface-mounted parts on a printed circuit board. The surface mounter receives various surface-mounted parts supplied in the form of tape, stick, and tray from a feeder and places them on the mounting position on the printed circuit board. Perform.

The vision inspection apparatus inspects the mounting state of the surface mount component before or after the soldering process of the surface mount component is completed and transfers the printed circuit board to the next process according to the inspection result.

A typical vision inspection apparatus includes a lighting unit to which light is irradiated using a lamp or the like, a camera unit for photographing image information of various components mounted on an inspection unit and reflecting light from the lighting unit. It comprises a half mirror for transmitting the shape of the inspection object to the camera unit while being reflected on the inspection object.

Here, the lighting unit is arranged in the housing by arranging a plurality of lamps in a plurality, when the illumination of the inspection object to supply power to the plurality of lamps to irradiate light.

Conventional vision inspection method, when the inspection object is transported horizontally through the conveyor, adjusts the initial position in the positioning device, and after the adjustment is completed and irradiated with light through the grid on the LED component or printed circuit board, the irradiated light is By analyzing the shadow shape formed on the surface of the inspection object, the three-dimensional height is measured.

Then, by calculating the photographing part and comparing with the reference value, the inspection of the good / bad of the component mounting associated with the height, or the presence / absence of the mounting of the surface mounting component.

All of the above inspection methods measure the two-dimensional shadow shape and calculate the three-dimensional height by using a trigonometric function.

Therefore, clearly photographing and distinguishing the shadow pattern formed by the irradiated light is a very important factor in the vision inspection apparatus using the structured light.

However, as shown in FIG. 1, when the grid object is irradiated with a plaid light on a test object having a height and is photographed in plan view, if the height of the test object is relatively very high than the spacing of the grid pattern, the grid pattern is irradiated on the test object. It is not possible to distinguish which of (1, 2, 3) and the bottom lattice 1-1, 2-1, 3-1 are the same lattice in the first place.

Therefore, such a factor may cause an error in height inspection, which increases the number of image photographs required for height measurement to eliminate such an error, and complicates the height calculation process based on the image photograph. This delays the overall time spent.

On the other hand, all of the above inspection method to calculate the three-dimensional height by measuring the two-dimensional shadow shape using a trigonometric function.

However, as shown in FIG. 2, the conventional vision inspection apparatus includes an illumination unit 110 to which light is irradiated using a lamp and the like, and an image of various components installed on the inspection object by being installed on the illumination unit 110. And a half mirror 130 for reflecting the light from the illumination unit 110 to capture information and transmitting the shape of the inspection object to the camera while reflecting light from the illumination unit 110.

Here, the lighting unit 110 is arranged in the housing 140 by arranging a plurality of lamps, and, when irradiating the light to the inspection object to supply power to the plurality of lamps to irradiate light.

In the conventional vision inspection apparatus, a half mirror provided for capturing an image while reflecting light is disposed in front of the central camera unit, thereby preventing a clearer image.

In addition, since the light from the lighting unit is directly irradiated on the surface of the inspection object, there is a problem that the portion of the light is directly irradiated by overlapping the light is relatively dark while the portion of the light density is relatively dark.

In addition, since a configuration such as a laser or a camera for recognizing whether the inspection target substrate is mounted in the correct position is accommodated in the central camera portion, the type of the overall configuration accommodated in the housing for accommodating the central camera; The increase in size and weight causes inconvenience in maintenance.

The present invention has been made to solve the above problems, to provide a vision inspection apparatus capable of measuring the height of the inspection object quickly and accurately.

Still another object of the present invention is to provide a vision inspection apparatus capable of improving the uniformity of light irradiated onto a surface of an inspection object.

Still another object of the present invention is to provide a vision inspection apparatus capable of capturing a clearer image by removing a half mirror disposed in front of a central camera unit.

Vision inspection apparatus according to the present invention for achieving the above object is to determine the good or bad of the inspection object by comparing the photographed image with the pre-input target image after taking the inspection object assembled or mounted during the assembly of the parts with the camera An apparatus for vision inspection, comprising: a stage unit for fixing or transferring an inspection object to an inspection position, an illumination unit positioned at an upper portion of the stage unit and providing illumination to the inspection object, and positioned at a center of the illumination unit A central camera unit for acquiring a two-dimensional shape of the camera, a side camera unit disposed in a plurality of sides of the central camera unit, a grid pattern irradiation unit disposed in the side of the central camera unit, and an image photographed by the central camera unit A vision processor which reads out and determines whether the inspection object is good or bad; And a control unit for controlling the grid pattern irradiation unit and the camera unit, wherein two predetermined cameras of the side camera unit photograph the inspection object to measure the height of the inspection object, and one of the grid pattern irradiation units It is configured to measure the height by examining it.

Here, the grid pattern irradiation unit comprises any one of a liquid crystal panel or a micromirror module.

Preferably, the height measured by the irradiated grid pattern is configured to have a resolution larger than the height of the inspection object measured by the two cameras.

Preferably, the plurality of grid pattern irradiation units are disposed.

Meanwhile, a light diffusing unit is disposed in front of the lighting unit.

The lighting unit may include a horizontal lighting unit for irradiating light in a vertically downward direction and an inclined lighting unit for irradiating light in an oblique direction.

Preferably, the plurality of grid pattern irradiation units are disposed to face each other with respect to the central camera unit.

Preferably, the side camera portions are disposed to face each other with respect to the center camera portion.

On the other hand, the light diffusing unit may be disposed in front of both the horizontal lighting unit and the inclined lighting unit.

In addition, a positioning camera unit for checking the position of the inspection object may be disposed at one side of the central camera unit.

Here, the positioning lighting unit and the half mirror may be disposed in front of the positioning camera unit.

Preferably, the angle between the central camera portion and the grid pattern irradiation portion on the side view is 25 degrees to 45 degrees.

According to the present invention, the height of the inspection object can be calculated quickly and accurately.

In addition, the uniformity of the light irradiated on the surface of the inspection object can be improved.

In addition, by removing the half mirror disposed in front of the center camera portion, it is possible to capture a clearer image.

Fig. 1A is a perspective view showing a state in which a lattice pattern is irradiated to the part.

FIG.1 (b) is a top view which shows the state which irradiated the grid with a component.

2 is a side cross-sectional view of a conventional vision inspection apparatus.

3 is a schematic side view of a vision inspection apparatus according to the present invention.

4 is a schematic plan view of a vision inspection apparatus according to the present invention.

5 is a conceptual diagram showing the relationship between the period of the lattice pattern and the height of the parts.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration of the present invention.

Prior to this, the terms used in this specification and claims should not be construed in a dictionary sense, and the inventors may properly define the concept of terms in order to explain their invention in the best way. It should be construed as meaning and concept consistent with the technical spirit of the present invention.

Therefore, the configurations shown in the embodiments and drawings described herein are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It is to be understood that water and variations may exist.

3 is a schematic side view of a vision inspection apparatus according to the present invention, Figure 4 is a schematic plan view of the vision inspection apparatus according to the present invention.

3 and 4, the vision inspection apparatus according to the present invention after taking the inspection object 5 assembled or mounted in the assembly process of the part with a camera and compares the photographed image with the previously input target image ( 5) A vision inspection apparatus for discriminating good or bad of 5), the stage unit 10 for fixing or conveying the inspection object 5 to the inspection position, and the upper portion of the stage unit 10, the inspection An illumination unit 20 for providing illumination to the object 5, a central camera unit 30 positioned at the center of the illumination unit 20 to obtain a two-dimensional shape of the inspection object 5, and the central camera unit A side camera portion disposed in plural on the side of 30, lattice pattern irradiation portions 50-2, 50-4, 50-6, and 50-8 disposed on the side of the central camera portion 30; The image taken by the central camera unit 30 is read and the Vision control unit 60 for determining a defect, and the control unit 70 for controlling the stage unit 10, the grid pattern irradiation unit and the camera unit, two cameras of the side of the predetermined camera unit ( 5) photographing to measure the height of the test object, any one of the grid pattern irradiation unit (50-2, 50-4, 50-6, 50-8) is configured to measure the height by irradiating the grid pattern.

Vision inspection apparatus of the present invention is installed to perform the vision inspection before moving to the next process through the conveyor of the preceding equipment, when inspecting the surface-mounted parts of the printed circuit board after the surface mounting work in the surface mounting line .

Such vision inspection apparatus can be installed in a manner that is arranged in the space formed between the conveyor of the line, trailing equipment and the conveyor, can also be used in the form of a single table without being connected to the line, trailing equipment.

Here, the stage unit 10 is a component that provides a space in which the inspected object 5 to be inspected is seated, and a position adjusting unit (not shown) and a high position for adjusting and fixing the position of the inspected object 5. It may be configured to include a government (not shown).

Here, the lighting unit 20 is installed on the upper portion of the stage unit 10 continuously or intermittently along the circumferential direction around the central camera unit 30.

The lighting unit 20 is a component that provides illumination to the inspection object 5 in order to secure accurate image information of the inspection object 5, by placing a plurality of lamps or LED bulbs to the inspection object (5) ) Can be arranged to illuminate from side to side.

The lighting unit 20 includes a horizontal lighting unit 22 and the inclined lighting unit 23.

Here, the horizontal lighting unit 22 is installed on the upper portion of the stage 10 serves to provide the light incident to the inspection object (5) perpendicularly.

The inclined light unit 23 is disposed at the side of the vertical light unit 22 to provide light in the oblique direction.

The central camera unit 30 is a component for photographing the inspection object 5 in a plan view, and preferably, may be provided as a charge coupled device (CCD) camera.

The grid irradiated by the grid pattern irradiation unit 50-2, 50-4, 50-6, and 50-8 while performing the two-dimensional inspection of the inspection object 5 by the central camera unit 30. By measuring the degree of deformation of the pattern can be measured the height of the inspection object.

In the case of the conventional vision inspection apparatus, a half mirror is disposed in front of the center camera unit, and reflects the light from the lighting unit, and is configured to capture an image through the camera. In the present invention, the center camera unit 30 No half mirror is placed in front.

Therefore, it is possible to capture a clearer image through the central camera unit 30.

A plurality of side camera units 40-2, 40-4, 40-6, and 40-8 are arranged symmetrically with respect to the center camera unit 30 on the side of the central camera unit 30, thereby providing an image. Eliminate blind spots and take pictures quickly.

As shown in FIG. 4, the four side camera parts 40-2, 40-4, 40-6, and 40-8 are symmetrically arranged with respect to the center camera part 30, such as a substrate. Examine the lifting and uninsertion of the parts placed on the inspection object.

In addition, by taking images of the inspection object through two predetermined cameras among the side cameras 40-2, 40-4, 40-6, and 40-8, three-dimensional spatial coordinates ( The height of the inspection object is measured by obtaining x, y, z) and comparing it with the spatial coordinates serving as reference points of the inspection.

However, since there is a limitation in the resolution of the height that can be recognized by the distance recognition (height recognition) technology using the stereo camera as described above, the grid pattern irradiation unit 50-2, 50- to compensate for the limitation of the resolution as described above. 4, 50-6, 50-8 to measure the height by capturing the grid pattern is irradiated by the central camera unit 30 to measure the finer height.

Therefore, the height measured by the grid pattern irradiated by the grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8 is the height of the inspection object measured by the two cameras (stereo vision) It is configured to have a higher resolution (more detailed height measurement).

The grid pattern irradiation unit (50-2, 50-4, 50-6, 50-8) is a configuration for measuring the height by irradiating the grid pattern on the inspection object 5, a liquid crystal panel or a digital micromirror display ( DMD: Digital Micromirror Display and light source.

Thus, the shadow of the grid-shaped shadow is irradiated onto the inspection object 5 under the control of the control unit 70, and the degree of deformation of the grid-shaped shadow through the central camera unit 30, We can calculate the height of.

The grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8 also has four grid pattern irradiation units 50-2, 50-4, 50-6, centered on the central camera unit 30. 50-8) are arranged symmetrically, and configured to irradiate the grid 5 to the inspection object 5 selectively.

Preferably, the arrangement angle a between the grid pattern irradiation unit 50-2, 50-4, 50-6, 50-8 and the central camera unit 30 is arranged in an angle range of 25 degrees to 45 degrees. .

When the angle (a) is smaller than 25 degrees, the degree of deformation of the grid pattern according to the height of the component is small, which may cause an error in the height calculation. When the angle (a) is larger than 45 degrees, the grid pattern irradiation unit ( 50-2, 50-4, 50-6, 50-8), the difference in the width of the grid pattern irradiated on the near and far sides is too large, which may cause errors in the height calculation.

This is because, when disposed in the angular range, when the irradiated grid pattern is photographed through the central camera unit 30, the grid pattern is properly deformed according to the height of the inspection object.

On the other hand, the vision processor 60 calculates the image information of the inspection object (5) obtained from the camera unit through a mathematical process, and compares the good or bad of the inspection object (5) by comparing it with a reference value input in advance To judge.

In addition, the controller 70 is a component including a motion controller for controlling the driving and operation of the stage unit 10, the first and second camera units, and is provided to control the driving of the entire vision inspection apparatus according to the present invention. Can be.

The controller 70 is responsible for physical control such as photographing position control of the vision inspection apparatus, processing of photographed images, and lighting unit control according to a system control program, as well as performing inspection task and data calculation task.

In addition, the control unit 70 is in charge of the overall control of the vision inspection apparatus, such as output device control for outputting the work contents and inspection results to the monitor and input device control for the operator to input the settings and all the details.

On the other hand, the light diffusion unit 25, such as a light diffusion plate is disposed in front of the illumination unit 20, so that the light from the illumination unit 20 is evenly irradiated to the entire area of the inspection object.

Thus, by reducing the difference between the dark portion and the bright portion on the inspection object (5) can take a clearer image.

The light diffusion unit 25 is configured to be bent in a side cross-section so that the light diffusion unit 25 can be disposed in front of both the horizontal light unit 22 and the inclined light unit 23.

On the other hand, at one side of the central camera unit 30 is positioned a positioning camera unit 80 for checking the position of the inspection object.

Here, the positioning lighting unit 84 and the half mirror 82 is disposed in front of the positioning camera unit 80.

Thus, compared to the case of confirming the position of the inspection object through the conventional central camera, the configuration for positioning is accommodated in the housing of the separate positioning camera unit 80, thereby reducing the housing diameter of the central camera unit 30 It can be reduced and management is easy even in case of accessory failure.

5 is a conceptual diagram illustrating an operation principle of a vision inspection apparatus using a stereo vision and a plaid according to the present invention.

First, in FIG. 5, a straight line connecting the points a, b, c and d conceptually shows the height that can be measured by stereo vision.

That is, for example, if the height that can be measured by stereo vision has a resolution of 500 micrometers, all heights from 0 to 500 micrometers are recognized as the same height, and another height from 500 to 1000 micrometers To be recognized.

This conceptually describes the resolution when measuring the height of a part using stereo vision, and the specific number may vary.

The stereo vision method primarily measures the approximate height of the component.

That is, when the height of the hexahedral component illustrated in FIG. 5 is 1680 micrometers, the height of the component is primarily measured in the range of 1500 and 2000 micrometers through stereo vision.

As a next step, the grid pattern is examined to determine that the height from point d to point R is 180 micrometers.

Thus, the total height of the part is 1500 + 180, measured 1680 micrometers.

If the height of the part is measured by using only one lattice without height measurement process through stereo vision, the lattice pattern matching the first lattice pattern on the left side in FIG. 1 is 1-1 lattice pattern on the right side. It is not possible to determine whether the lattice 1 or 3-1 lattice pattern, that is, whether the lattice pattern on the upper surface of the part and the lattice pattern on the bottom surface coincide after several cycles (lattice spacing).

However, if the fine height is measured through the lattice in the state where the approximate height is measured first through the stereo vision, it is possible to determine whether the lattice matches after several cycles.

In the present invention, as described above, while using a stereo vision and a higher resolution fine grid, together with the stereo vision to measure the approximate height range, a more precise grid can be used to measure a more accurate height By doing so, the height inspection can be performed quickly and accurately.

The stereo vision and the plaid is measured according to the requirements of the height inspection device, respectively, once the stereo vision and the plaid, or the stereo vision is taken once, the plaid is measured by moving the upper surface of the inspection object more accurate height measurement It may be configured to enable.

As mentioned above, although the present invention has been described by way of limited embodiments and drawings, the technical idea of the present invention is not limited thereto, and a person having ordinary skill in the art to which the present invention pertains, Various modifications and variations may be made without departing from the scope of the appended claims.

Claims

A vision inspection device for determining whether the inspection object is good or bad by taking a photograph of an inspection object assembled or mounted in a component assembly process and comparing the photographed image with a previously input target image.

A stage unit for fixing or transferring the inspection object to an inspection position;

An illumination unit positioned above the stage unit and providing illumination to the inspection object;

A central camera unit positioned at the center of the illumination unit to obtain a two-dimensional shape of an inspection object;

A side camera unit disposed in a plurality of side portions of the central camera unit;

A lattice pattern irradiation unit disposed at the side of the central camera unit;

A vision processing unit which reads the image photographed by the central camera unit and determines whether the inspection object is good or bad;

A control unit for controlling the stage unit, the grid pattern irradiation unit, and the camera unit,

Two predetermined cameras of the side camera unit photograph the inspection object to measure the height of the inspection object, and the grid pattern irradiator is configured to measure the height by measuring the grid pattern to the stereo vision and the grid pattern Vision inspection device used.
The method of claim 1,

The grid pattern irradiation unit is a stereo vision and a grid inspection vision inspection device comprising any one of a liquid crystal panel or a micromirror module.
The method of claim 1,

And a height measured by the irradiated lattice pattern is configured to have a resolution larger than the heights of the test objects measured by the two cameras.
The method of claim 1,

Stereo grid and a vision inspection device using a grid pattern, characterized in that the plurality of grid pattern irradiation unit is disposed.
The method of claim 1,

Stereo vision and a vision inspection device using a grid pattern, characterized in that the light diffusion unit is disposed in front of the lighting unit.
The method of claim 1,

The lighting unit is a stereo vision and grid pattern vision inspection apparatus comprising a horizontal lighting unit for irradiating light in the vertical and downward direction and an inclined lighting unit for irradiating light in the oblique direction.
The method of claim 1,

The plurality of grid pattern irradiation unit is a vision inspection apparatus using a stereo vision and a grid pattern, characterized in that disposed opposite to each other centered on the central camera unit.
The method of claim 1,

The side camera unit is a vision inspection device using a stereo vision and a grid characterized in that the center camera is disposed opposite each other.
The method of claim 1,

And the light diffusing unit is disposed in front of both the horizontal lighting unit and the inclined lighting unit.
The method of claim 1,

Stereo vision and a vision inspection device using a lattice pattern, characterized in that the positioning camera unit for positioning the inspection object on one side of the central camera unit.
The method of claim 10,

Stereo vision and a vision inspection device using a plaid, characterized in that the positioning illumination unit and the half mirror is disposed in front of the positioning camera unit.
The method of claim 1,

Stereo vision and a vision inspection device using a grid pattern, characterized in that the angle between the central camera portion and the grid pattern irradiation section on the side view is 25 degrees to 45 degrees.