JPH10170223A - Positioning system and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning system and its method for quickly and accurately positioning a robot arm and a production tool. SOLUTION: An image pickup means 3 equipped with an image forming means 2 consisting of a zoom lens which can be changed into a wide position 2A or a tele-position 2B is fixed on a position moving means 10, and the image pickup means 3 carrys out a broad view photographing at the wide position 2A, and an image processing means 4 discovers a detection object out of taken-in broad view images by a template matcing method, and operates a movable stage so that a characteristic point in the image may be located at the center of a picture to optionally roughly position, and when the photographing is enlargedly carried out at the tele-position 2B, a computer 4 recognizes the characteristic point on the broad view image by the template matching method, and operates the moving stage 10 so that the characteristic point may be located at the center of the picture to carry out highly accurate positioning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning system and a positioning method using image processing, and more particularly to a positioning system and a positioning method for a robot arm and a production tool in automation of production and the like.

[0002]

2. Description of the Related Art At present, recognition and position detection of products and positioning of production tools using image processing technology are actively performed mainly in the semiconductor industry and the automobile industry. In particular, many semiconductor chips are similar in size, and a positioning system that can handle multiple types with a single optical system and a positioning system that can easily handle multiple types by applying a zoom mechanism have been proposed. I have.

As such a conventional technique, there is one disclosed in, for example, Japanese Patent Application Laid-Open No. 4-355938.
This enables detection of lead shapes, positions, and postures of a plurality of types of ICs by setting the field of view of a zoom optical system according to the external dimensions of the ICs.

[0004]

However, in the case where the product size does not greatly differ depending on the type of IC, the above-described prior art is effective in securing the field of view, but the positioning operation is difficult. Again, there is a disadvantage that the accuracy must be dependent on the moving mechanism system.

In order to rationalize production, only small changes such as the layout of production parts and the printing and printing of the manufacturer name and the like are made. It is effective in the case of multi-mix production, because detecting the position of each object to the mechanism every time is not affected by the production schedule and it can cope with accidental accidents such as line drop, etc. However, the prior art has a problem that it is difficult to flexibly deal with such a configuration.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and is intended for positioning a robot arm and a production tool in production automation or the like.
It is an object of the present invention to provide a positioning system and a positioning method that execute quickly and with high accuracy.

[0007]

In order to solve the above-mentioned problems, a positioning system according to the present invention comprises: imaging means having a zoom mechanism; imaging means for photographing an object to be detected via the imaging means; A position moving unit for mounting and moving the imaging unit; and an image processing unit for processing image data input by the imaging unit, wherein the zoom mechanism can be switched at least between a wide position and a tele position. Means for setting the zoom mechanism to the wide position,
The wide-field imaging including the feature point on the object is performed, and the image processing unit recognizes the feature point by template matching from the captured wide-field image, and the position moving unit performs the center recognition on the screen by the position moving unit. The provisional coarse positioning is performed, and then the imaging unit sets the zoom mechanism to the telephoto position, performs enlarged photographing in which a feature point on the object appears in the center of the screen, and the image processing unit The feature point is recognized by template matching based on the enlarged field-of-view image, and highly accurate positioning is performed by the position moving means so as to be at the center of the screen.

As described above, by two-stage shooting and matching processing by rough positioning and high-precision positioning, detection characteristics having similar characteristics are arranged at different positions on the surface of a plurality of types of parts having a large area. However, the relative positions of the detected feature points and the imaging means can be adjusted with high accuracy for each of the plurality of types of components.

In a positioning method according to the present invention, as a pre-procedure for performing positioning using the positioning system according to the first aspect, a zoom mechanism is set to a wide position and a tele position to photograph a detection standard object. The procedure of storing the image centered on the feature point of the detection standard object as a template, setting the zoom mechanism to the wide position, capturing an image, searching for an object to be detected from within the imaging range by template matching, A step of detecting a relative distance between a feature point of a detection target and a feature point of the template; a step of performing coarse positioning when the zoom mechanism is at a wide position based on the detected relative distance; After the positioning of the accuracy, the zoom mechanism is set to the tele position to capture an image, and the feature points of the detection target and the template A step of detecting a relative distance between the feature points, from the detected relative distance, wherein the zoom mechanism and a procedure for the precise positioning when in the telephoto side position.

[0010] With the above-described configuration, provisional positioning is performed by confirming that the detection target is a desired target and by performing coarse positioning without causing a feature point to be out of the image plane.
Precise positioning enables high-precision positioning.

Alternatively, the positioning method according to the present invention comprises:
In the above, it is also possible to realize a configuration in which only the template when the zoom mechanism is in the wide position is stored, and an image obtained by enlarging the template by the magnification of the zoom ratio is used as the template when in the tele position.

With the above configuration, the amount of image memory required for storing a template is reduced, and the time spent for reading an image on the memory is reduced.

Alternatively, the positioning method according to the present invention comprises:
A procedure for gradually adjusting the zoom mechanism from the wide position to the telephoto position, a procedure for storing a template corresponding to a zoom ratio that is gradually and gradually adjusted, and a procedure for storing the template. Read the template,
It can also be realized by a configuration having a procedure for performing positioning by matching.

With the above configuration, it is possible to prevent a feature point from deviating from the image plane due to a significant change in the zoom ratio.

Alternatively, the positioning method according to the present invention comprises:
In the above, the present invention can also be realized by a configuration including a procedure of capturing an image of a feature point after positioning, enlarging the image by storage digital zoom, and using the image as a template in the next step.

According to the above-described configuration, a more precise positioning can be achieved by compensating for the lack of resolution of the template.

Alternatively, the positioning method according to the present invention comprises:
The zoom mechanism can be gradually adjusted from the wide position to the tele position gradually, and at the matching stage after each zoom ratio imaging,
A template obtained by enlarging the immediately preceding captured image based on the zoom ratio is used as a template.

With the above configuration, it is possible to reduce the time required to read a template and the hardware for storing a huge amount of template at each stage, and realize high-speed, high-accuracy, and highly-reliable positioning. .

[0019]

Embodiments of the present invention will be described below. FIG. 1 is a configuration diagram of an embodiment of a positioning system according to the present invention. As shown in FIG. 1, a positioning system 1 according to the present invention includes a zoom mechanism (image forming means) including a zoom lens on a moving stage (position moving means) 10 having a moving mechanism in L and H directions. 2 is fixed as the image pickup means 3. The zoom mechanism 2 is switchable between at least the wide position 2A and the tele position 2B. Computer (image processing means) 4
Captures image data input by the imaging unit 3 and performs image processing, control of a moving stage, and control of a zoom lens.

In operation, the imaging means 3 sets the zoom mechanism 2 to the wide position 2A first, and performs wide-field photographing of the entire area including the feature points on the detected object. Computer 4
In the captured wide-field image, template matching is performed to search for a detection target from the entire image without misunderstanding as other features or noise, and feature points indicating the position of the template in the image are recognized. Next, the moving stage 10 is operated so that the feature point is located at the center of the screen, and provisional coarse positioning is performed while the resolution remains coarse.

Next, the image pickup means 3 sets the zoom mechanism 2 at the tele position 2B, and performs enlarged photographing in which a feature point on the detected object appears at the center of the screen. The computer 4 recognizes feature points by template matching based on the captured enlarged field-of-view image, operates the moving stage 10 so as to be at the center of the screen, and performs highly accurate positioning. At this time, since the tentative positioning has already been performed at the wide position, the positioning at the time of high resolution can be completed by the movement of the zoom ratio × the tentative positioning accuracy at the maximum, so that the positioning speed can be improved.

As described above, the positioning system according to the present invention can be used for parts and printing /
First, coarse positioning is performed by setting the zoom mechanism to the wide side and imaging the object, and then switching the zoom mechanism to the tele side to increase the resolution for each product that has a unique arrangement of objects that can be an index for positioning such as printing. High-accuracy positioning is enabled by imaging the object at an elevated position.

That is, by two-stage shooting and matching processing by rough positioning and high-precision positioning, detection features having similar features are arranged at different positions on the surface of a plurality of types of parts having a large area. Also, the relative position between the detected feature point and the imaging means can be adjusted with high accuracy for each of the plurality of types of components.

Next, the details of the positioning method using the positioning system shown in FIG. 1 will be described below. As shown in FIGS. 2 and 3, FIG. 7 shows images of different parts 6 a and 6 b having the same feature points (detection targets) 5 a and 5 b on the surface when the state of the zoom mechanism is the wide position. Scanning is performed using the template image 7, and the feature points 5a and 5b
In each case, a correlation is obtained, the position is detected, and provisional positioning is performed without erroneously detecting the notch 8 by pattern matching.

Next, as shown in FIGS. 5 and 6, when the state of the zoom mechanism is the telephoto position, the same characteristic points 5a,
Correlation between the magnified images 51a and 51b of 5b and the template image 71 at the tele position shown in FIG. 7 is performed, the position is detected by pattern matching, and positioning with high accuracy is performed.

FIG. 8 shows a processing flow of the above operation. When the state of the zoom mechanism is at the wide position, the image is captured (step S1), the template image at the wide position is read (step S2), and pattern matching is performed (step S1).
3) Perform temporary positioning (step S4), then zoom to the tele position (step S5), read the template image at the tele position (step S6), perform pattern matching (step S7), and perform high-precision positioning. Execute (step S8).

According to the positioning method of the present invention, coarse positioning is performed on the wide side by the zoom mechanism, and at the same time, the object to be detected is adjusted to be captured in the image plane. Then, the zoom mechanism is switched to the tele side to increase the resolution and increase the resolution. Accurate positioning is performed, and by performing such stepwise positioning, it is possible to prevent a detection target from coming off the image surface due to a sudden change in the zoom ratio, such as positioning at the periphery of the image surface. That is, the field of view is reduced by increasing the resolution as in the related art, and inconveniences such as the object to be detected coming out of the image plane can be prevented at the time of provisional positioning before image capturing.

Alternatively, according to the positioning method of the present invention, the image of the object to be detected captured on the wide side is enlarged by the zoom ratio from the wide position to the tele position, and this enlarged image is used as a template on the tele side. It can also be configured. That is, instead of storing and reading out the template 71 at the tele position as described above, only the template 7 when the zoom mechanism is at the wide position is stored, and an image obtained by enlarging the template by a zoom ratio is displayed. It is configured to be used as a template for positioning. For example, for simplicity, the zoom ratio is limited to an integer multiple to facilitate enlargement of image data.

FIG. 9 shows a processing flow of this positioning method. The same steps as those in the processing flow of FIG. 8 are given the same numbers. Unlike the processing flow of FIG. 8, after step S5, the template image at the wide position is enlarged by the zoom ratio (step S16), and pattern matching is performed (step S7).

As described above, only the template at the wide position is stored, and an image obtained by enlarging the template by the magnification of the zoom ratio is used as the template at the tele position. The amount of data can be reduced, and the time spent for reading the image on the memory can be reduced.

According to another positioning method of the present invention, a procedure for gradually and gradually adjusting a zoom mechanism from a wide position to a telephoto position and storing a template corresponding to a gradually and gradually adjusted zoom ratio are stored. And a procedure for reading the template stored at each stage and performing positioning by matching. That is, the adjustment of the zoom mechanism from the wide side to the tele side is gradually performed step by step, and in each case, a template stored in advance at a zoom ratio corresponding to each of the steps is read out, and sequentially high-precision. Perform positioning.

This is, as shown in FIG.
Template 7 corresponding to n1 times, × n2 times, × n3 times
01, 702, and 703 are stored, and each time the zoom ratio of the zoom lens is adjusted, the template at that stage is read out, and position detection and positioning are performed by pattern matching.

FIG. 11 shows a processing flow of this positioning method. The same steps as those in the processing flow of FIG. 8 are given the same numbers. Unlike the processing flow of FIG. 8, after step S5, the corresponding template is read from the template image group at the telephoto position (step S26), and the position is determined by pattern matching (step S7) (step S8). Further, the process loops from step S29 to step S5.

With the above-described configuration, it is possible to prevent the feature point of the object to be detected from deviating from the field of view when the zoom ratio is largely changed, thereby enabling stable positioning.

Further, another positioning method according to the present invention is a method of taking an image of a feature point at a wide position, performing several steps of enlargement by a stored digital zoom based on the image, and forming a template at each zoom. Prepare. That is, the template obtained at the wide position is enlarged and applied in several steps. As in the operation flow shown in FIG. 12, instead of storing and reading templates at each zoom ratio, the template obtained at the wide position is enlarged by the zoom ratio for each zoom (step S32), and the zoom ratio is changed. Use as a template for

With the above configuration, the memory capacity for storing templates requiring an enormous capacity is reduced, and the time required for reading out the templates is reduced, so that the positioning time can be reduced. More accurate positioning can be achieved by compensating for the lack of resolution of the template.

Still another positioning method of the present invention is shown in FIG.
As in the operation flow shown in FIG. 3, in the matching stage after each zoom ratio imaging, a template obtained by enlarging the immediately preceding captured image based on the zoom ratio is used as a template (step S4).
1), pattern matching is performed using this. That is, after adjusting the zoom ratio and performing pattern matching, position detection, and positioning, the raw image is used as the original image of the template in the next stage. The magnification ratio of the image is n1 at each stage.
Times, n2 / n1 times, n3 / n2 times,...

With the above-described configuration, it is possible to reduce the time required to read a template and the hardware for storing a huge amount of template at each stage, thereby realizing high-speed, high-accuracy, and highly-reliable positioning. .

As described above, the positioning system and the positioning method according to the present invention provide a quick and high-precision processing for performing the positioning of the robot arm and the positioning of the production tool by using image processing by automation of production or the like. In order to achieve the above, first, a wide field of view is detected, and provisional coarse positioning before image capture is performed. In the subsequent stage, high-resolution detection per pixel pitch is performed to improve positioning accuracy. This enables high-precision, highly-reliable positioning in two stages.

Therefore, as an application field of the positioning system and the positioning method according to the present invention, for example, the size of the product itself, a maker logo printed on the surface of the product, a feature that can be an index at the time of positioning, etc. There is an automatic production line for a copying machine or the like having a large difference in size from a point, and is suitable for application to these fields.

[0041]

As described in detail above, claim 1 of the present invention
According to the positioning system according to the first aspect, the feature point is coarsely positioned by using a low-resolution but wide-field image as a first step by using a zoom mechanism for the object to be detected, and thereby the approximate position in the image plane is determined. Is detected, and as a second step, positioning with higher accuracy is performed based on a high-resolution enlarged image, so that highly reliable positioning can be performed.

According to the positioning method according to the second aspect of the present invention, coarse positioning can be performed by using pattern matching for positioning by distinguishing it from other features existing in the image plane for a wide field of view. High-resolution images enable highly accurate and reliable positioning.

According to the positioning method of the third aspect of the present invention, the hardware for storing the template used for pattern matching is reduced, and the processing time is reduced from the image data reading time to the data processing on the memory. And high-speed positioning can be performed at low cost.

According to the positioning method according to the fourth aspect of the present invention, the zoom ratio is changed stepwise and adjusted, and each time the positioning is performed using the template corresponding to each zoom ratio, the zoom ratio is greatly increased. In the case of changing and adjusting to, or when it is necessary to position at the inner edge of the image plane, it is possible to prevent feature points from deviating from the image plane, and ultimately improve the reliability of positioning. Will be possible.

According to the positioning method according to the fifth aspect of the present invention, it is possible to reduce the digital noise accompanying the image enlargement at the time of creating the template, and to achieve the effect of enabling highly accurate positioning.

According to the positioning method according to the sixth aspect of the present invention, the memory capacity and the time required to read the template image can be reduced, thereby enabling high-speed positioning at low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of a positioning system according to the present invention.

FIG. 2 is a schematic diagram of a screen example of the positioning system of FIG. 1;

FIG. 3 is a schematic view of a screen example of the positioning system of FIG. 1;

FIG. 4 is a diagram showing a template image.

FIG. 5 is a view of a feature point enlarged in zoom;

FIG. 6 is a view of a feature point that has been zoomed in;

FIG. 7 is a zoomed-in template image.

FIG. 8 is a flowchart of an embodiment of a positioning method according to the present invention.

FIG. 9 is a flowchart of another embodiment of the positioning method according to the present invention.

FIG. 10 is an explanatory diagram of an operation of still another embodiment of the positioning method according to the present invention.

11 is a flowchart of the positioning method shown in FIG.

FIG. 12 is a flowchart of another embodiment of the positioning method according to the present invention.

FIG. 13 is a flowchart of still another embodiment of the positioning method according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 positioning system 2 zoom mechanism (imaging means) 2A wide position 2B tele position 3 CCD camera (imaging device) 4 computer (image processing means) 5a, 5b, 51a, 51b Features on detection target 6a, 6b Detection target 7 , 71, 701 Template / template group 8 Notched part of component 10 Moving stage (position moving means)

Claims (6)

[Claims] 1. An imaging means having a zoom mechanism, an imaging means for photographing an object to be detected through the imaging means,
A position moving unit that mounts and moves the imaging unit; and an image processing unit that processes image data input by the imaging unit, wherein the zoom mechanism is switchable at least between a wide position and a tele position. The means sets the zoom mechanism to the wide position, performs wide-field imaging including a feature point on the object, and the image processing means determines the feature point by template matching from the captured wide-field image. Recognizing the image, performing temporary coarse positioning by the position moving means so as to be at the center of the screen. Then, the imaging means sets the zoom mechanism to the tele position so that the feature point on the object is positioned at the center of the screen. The image processing means recognizes the feature points by template matching based on the captured enlarged field-of-view image. Positioning system being characterized in that a structure to perform high-precision positioning by comprising as said position moving means. 2. As a pre-procedure for executing positioning using the positioning system according to claim 1, the zoom mechanism is set to a wide position and a tele position, and a detection standard object is photographed.
A procedure for storing an image centered on the feature point of the detection standard object as a template, and setting the zoom mechanism to the wide position to capture an image, searching for a detection target object from an imaging range by template matching, A step of detecting a relative distance between a feature point of the detection object and a feature point of the template; and a step of performing coarse-accuracy positioning when the zoom mechanism is in a wide position from the detected relative distance. After positioning with coarse accuracy, setting the zoom mechanism to the tele position, capturing an image, and detecting a relative distance between a feature point of the detection target and a feature point of the template; and a detected relative distance. A step of performing precise positioning when the zoom mechanism is at the telephoto position. 3. In the positioning method, only a template when the zoom mechanism is at a wide position is stored.
The positioning method according to claim 2, wherein an image obtained by enlarging the template by a magnification of a zoom ratio is used as a template at a telephoto position. 4. A step of adjusting the zoom mechanism from a wide position to a telephoto position in a stepwise manner in the positioning method, and storing a template corresponding to a zoom ratio adjusted in a stepwise manner. 3. The positioning method according to claim 2, further comprising the steps of: reading a template stored at each stage and performing positioning by matching. 5. The positioning method according to claim 4, further comprising a step of taking an image of a feature point after positioning, performing enlargement in a plurality of stages by a storage digital zoom, and using the image as a template at each zoom. Positioning method. 6. In the positioning method, the zoom mechanism is capable of gradually adjusting the zoom position from the wide position to the tele position in a stepwise manner, and in a matching step after capturing each zoom ratio, the immediately preceding captured image is enlarged based on the zoom ratio. The positioning system according to claim 2, wherein the template is used as the template.