JP2002352232A - Image input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up the positional recognition processing of an object by picking up and inputting subject images of the object by a plurality of different illuminating conditions in one image. SOLUTION: A component 3 as the object is one-dimensionally transported and made to pass an image pickup area 21 of a CCD camera 4. The CCD camera 4 is made to be in an exposure state from a first position A to a second position B where the component 3 exists in the image pickup area 21. In this exposure time, when the component 3 comes to a third position C, a fourth position and a fifth position E in the image pickup area 21, each of a first illuminator 5, a second illuminator 6 and a third illuminator 7 is emitted for a short time by illumination signals from an illumination control part. Thus, the subject images of the component 3 illuminated by the plurality of illuminating conditions are picked up in one image and which can be simultaneously inputted as a plurality of images for recognition. The image for recognition can recognize a position and attitude of the component 3 by known algorithm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image input apparatus for picking up an image of an object and inputting its image when recognizing a component position in a component mounting process at the time of manufacturing a printed circuit board.

[0002]

2. Description of the Related Art Small electronic devices such as portable telephones and personal digital assistants have been further miniaturized and densified. In the production of printed circuit boards used in such electronic devices, electronic components have been used as substrates. There is a demand for higher-speed and higher-function electronic component mounting apparatuses to be mounted. In order to mount a very small electronic component at high speed, it is necessary to accurately recognize the position and orientation of the electronic component. For this reason, the component position recognition technology, which is the core technology of the mounting device,
More sophisticated processing is required.

[0003] In the electronic component mounting apparatus, in order to improve the mounting position accuracy, a method of correcting the displacement of the electronic component by image recognition is frequently used. In this method, the electronic component is picked up from the parts feeder by the transfer head and held, and the electronic component is imaged by the camera, and the imaging result is subjected to image processing to recognize the electronic component, thereby detecting a position shift. The electronic component is mounted on the substrate by correcting the positional deviation. Thus, the electronic component is accurately positioned and mounted at a correct position.

As a method of illuminating an electronic component with a camera, a method of illuminating the electronic component with illumination light from below and receiving reflected light from the electronic component with the camera, or providing the electronic component behind the electronic component is known. A method using transmission illumination that irradiates illumination light to a given reflection plate and receives this reflection light with a camera, and is also used when an electronic component with bumps formed on a thin substrate needs to recognize bumps. Various illumination methods such as one-way illumination are used.

When electronic components are recognized at the time of mounting, it is difficult to recognize the position and orientation under one illumination condition. Conventionally, an illumination unit having a plurality of light sources is used, and a plurality of images obtained for each illumination are used. Input and processing, the position and orientation of the electronic component were recognized.

[0006]

As described above, conventionally, when electronic components are imaged and recognized under a plurality of different illumination conditions, a plurality of images with different illumination conditions are imaged and input.
Recognition processing was performed on each image. However, in such a method, since it is necessary to input a plurality of images, it takes a long time to input an image, and there is a problem that high-speed recognition processing is difficult.

In addition, it is conceivable to simultaneously recognize the position and orientation of an electronic component by using a complicated algorithm for one image obtained by imaging the electronic component under a single illumination condition. Since it is difficult to secure lighting conditions, the load on the algorithm is inevitably increased, and the recognition rate and accuracy are deteriorated. As a result, there is a problem that the processing time becomes longer.

The present invention has been made in view of the above circumstances, and captures and inputs a subject image of a target object under a plurality of different lighting conditions into one image, thereby performing position recognition processing of the target object. It is an object of the present invention to provide an image input device capable of increasing the speed.

[0009]

An image input apparatus according to the present invention comprises: an image pickup means for picking up an image of an object; an illumination means for illuminating the object under a plurality of illumination conditions; An object moving unit that moves within the area, an imaging control unit that performs exposure control of the imaging unit, and an illumination control unit that performs light emission control of the illumination unit, and controls the imaging control unit and the illumination control unit. , A subject image of the object under a plurality of lighting conditions is captured in one image and input.

Preferably, the imaging means has an imaging element capable of arbitrarily controlling an exposure time by an external exposure signal, and the imaging control means includes means for imaging the object by the imaging means. Exposure control is performed such that an exposure signal is output and exposure is performed in the imaging unit while the object is in the area, and the illumination control unit emits light when the object is moving in the imaging area of the imaging unit. It is characterized in that light emission control is performed such that a signal is output to cause the lighting means to emit light at different positions under different lighting conditions.

Preferably, the object moving means has a one-axis stage for moving the object one-dimensionally within the imaging area of the imaging means, and the one-axis stage is located at the position of the object. The illumination means has a plurality of illumination devices each emitting illumination light under different illumination conditions, and the illumination control means outputs the linear scale output of the uniaxial stage. Based on the above, one of the plurality of lighting devices emits light when the object is located at two or more predetermined light emitting positions.

According to the present invention, while moving an object in the image pickup area of the image pickup means, the image pickup means is exposed to light for a predetermined period of time, and during that time, illumination light is emitted under a plurality of different illumination conditions. When the object is at a plurality of predetermined positions in a state where the object is at a plurality of predetermined positions for a short period of time, the illumination light is strobed for a short time under a plurality of illumination conditions, so that a subject image of the object under a plurality of different illumination conditions can be converted into one An image can be picked up and input in an image.

At this time, for example, when an electronic component, which is an object sucked and conveyed by a component suction nozzle attached to a uniaxial stage, passes through an imaging area of an imaging device such as a CCD camera while moving, During the exposure of the image pickup device, a short-time light emission is generated by the plurality of lighting devices at different times, and a subject image is recorded in one image by the lighting light of the plurality of lighting devices. The positions at which exposure is started and ended by the imaging device and the light emission positions at which the respective illumination devices emit light are determined in advance by the position of the target in the imaging area. The position of the object at this time is measured by a linear scale and a pulse counter attached to the uniaxial stage that conveys the object, and is in an exposure state while the object is passing through the imaging area. In, when the position of the object on the uniaxial stage comes to a light emission position stored in advance, the lighting device emits light.

As described above, a plurality of subject images obtained by capturing an object under different lighting conditions are recorded in one image, and a plurality of images are input at the same time, thereby shortening the image input time. In addition, since the subject images of a plurality of objects captured in one image can be quickly and accurately recognized by a known algorithm, the position of the object can be detected quickly and accurately.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an image input device according to one embodiment of the present invention. In the present embodiment, the configuration and operation will be described by taking an image recognition device for an electronic component mounting device as an example.

An image input device constituting an input unit in the image recognition device is a uniaxial stage 1 with a linear scale, which is an object moving means capable of being conveyed one-dimensionally in one axial direction.
A component suction nozzle 2 that moves on the transport axis together with the component 3 attached and suctioned on the uniaxial stage 1;
C which is an imaging means having an imaging device such as a CCD
A CD camera 4 and a first illuminating device 5, a second illuminating device 6, and a third illuminating device 7, which are illuminating means for illuminating the component 3 to be imaged under different illumination conditions, respectively, are provided.

The component suction nozzle 2 is set so as to suck a component 3, which is an electronic component such as a board mounted component, and move on the field of view of the CCD camera 4. In the vicinity of the uniaxial stage 1, a first illuminator 5, a second illuminator 6, and a third illuminator 7 are arranged together with the CCD camera 4.

The CCD camera 4 is connected to an image memory 9 via an A / D circuit 8, and an image signal picked up and output by the CCD camera 4 is converted by the A / D circuit 8 into, for example, 8-bit image data. And stored in the image memory 9. The CCD camera 4 is connected to an exposure control circuit 13 functioning as an imaging control means, so that the exposure time of the CCD camera 4 at the time of imaging is controlled. An illumination control circuit 14 functioning as illumination control means is connected to the first to third illumination devices 5 to 7, and the light emission time of each of the illumination devices 5, 6, and 7 depends on the position of the component 3 conveyed by the uniaxial stage 1. Is controlled.

A pulse counter 15 is connected to the single-axis stage 1, and pulses generated when the component suction nozzle 2 moves on the linear scale of the single-axis stage 1 are counted by the pulse counter 15, and the counter value is output. Is done. That is, the position information of the component 3 indicated by the counter value is output to the exposure control circuit 13 and the illumination control circuit 14.

A CP for controlling the operation of each part of the apparatus is provided.
U10, a program memory 11 storing an operation control program and the like, and a work memory 12 storing data of setting information used at the time of operation, etc., are provided. These are an exposure control circuit 13, an illumination control circuit 14, and an image memory 9. Are interconnected by a bus 16.

The CPU 10 performs image recognition processing on the image data stored in the image memory 9 in accordance with the processing procedure stored in the program memory 11, and recognizes the position and orientation of the component 3. The CPU 10 controls the exposure control circuit 13 and the illumination control circuit 14 in accordance with the information for controlling the exposure of the CCD camera 4 and the information for controlling the illumination stored in the work memory 12.

Under the control of the CPU 10, the exposure control circuit 13 inputs the position information of the component suction nozzle 2 on the uniaxial stage 1 output from the pulse counter 15, and the component 3 is positioned within the field of view of the CCD camera 4. An exposure signal is output to the CCD camera 4 from the time when the first position A is determined to the time when the second position B is reached. Thus, exposure is performed during the exposure time during which the exposure signal is output from the CCD camera 4, and an imaging signal of a subject image obtained by imaging the component 3 by photoelectric conversion is obtained.

The illumination control circuit 14 stores positional information on the uniaxial stage 1 as a plurality of preset light emitting positions, and outputs a component suction nozzle 2 on the uniaxial stage 1 output from the pulse counter 15. When the component 3 comes to the third position C in the field of view of the CCD camera 4, a light emission signal is output to the first lighting device 5.
Then, the first lighting device 5 emits light during the first emission time during which the emission signal is output, and the component 3 is illuminated by the first illumination light. Similarly, when the component 3 reaches the fourth position D in the field of view of the CCD camera 4, it outputs a light emission signal to the second lighting device 6. Then, the second lighting device 6 emits light during the second emission time during which the emission signal is output, and the component 3 is illuminated by the second illumination light. Furthermore, the component 3 is a CCD
When reaching the fifth position E in the field of view of the camera 4, a light emission signal is output to the third lighting device 7. Then, the third lighting device 7 emits light during the third emission time during which the emission signal is output, and the component 3 is illuminated by the third illumination light. By the above operation, illumination under a plurality of (here, three) illumination conditions is performed.

A first position A and a second position B indicating positions where exposure is started and ended by the CCD camera 4, and a third position indicating light emission positions at which the respective illumination devices 5 to 7 emit light.
The position C, the fourth position, and the fifth position E are determined in advance by the position of the component 3 in the imaging area. The position of the component 3 at this time is measured by a linear scale and a pulse counter attached to the uniaxial stage 1 for transporting the component 3, and the position of the component 3 on the uniaxial stage 1 is stored in advance. When the light emitting position is reached, the lighting devices 5 to 7 emit light.

The above-mentioned first to fifth positions A to E are stored in the work memory 12 in advance, and are read from the work memory 12 by the CPU 10 at appropriate times and set in the exposure control circuit 13 and the illumination control circuit 14, respectively.

Next, the above-described exposure control and illumination control will be described in more detail with reference to FIGS. FIG. 2 is an operation explanatory diagram for explaining an exposure time and a light emission time, and FIG.
Is a time chart showing the output timing of the exposure signal and the emission signal. In FIG. 2, the component suction nozzle 2 that suctions and holds the component 3 moves from left to right in the figure and passes through an imaging area 21 that is a field of view of the CCD camera 4. Here, the first illumination device 5 emits light and emits first illumination light when the component suction nozzle 2 comes to the third position C by the light emission signal as shown in FIG.
The second illumination device 6 emits light when it comes to the second position, and the second illumination light is emitted. When it comes to the fifth position E, the third illumination device 7 emits light and the third illumination light is emitted. Thus, the lighting conditions can be changed for each light emission. At this time, the lighting devices 5, 6, and 7 emit light for a very short time, and the lighting devices 5 to 7 do not emit light at the same time.

On the other hand, the exposure time of the CCD camera 4 is shown in FIG.
Is the time from the first position A, which is shortly before the component suction nozzle 2 reaches the third position C, to the second position B, which is shortly after passing through the fifth position E. That is, the component 3 conveyed by the uniaxial stage 1 is a CCD
The exposure state is always maintained during the time when the camera 4 passes through the imaging area after entering the imaging area. Thus, while the moving component 3 is located in the imaging area 21, the CCD camera 4 continuously performs exposure, and the illumination devices 5 to 7 are sequentially turned on at three different positions within this exposure time. By emitting the strobe light, subject images under three different lighting conditions are imaged side by side in one image of the component 3. As the photographing conditions at this time, for example, one exposure time is about 1 ms, and light emission of about 100 μs is performed plural times during this exposure time.

FIG. 4 shows an example of an image of the component 3 captured by the CCD camera 4 controlled as described above. In the imaging area 22, the first
A first illumination image 23 illuminated by the illumination light, a second illumination image 24 illuminated by the second illumination light, and a third illumination image 25 illuminated by the third illumination light are captured. That is, the subject images of the component 3 illuminated under the three illumination conditions are arranged and recorded side by side on one image, and the image data is sent to the CPU 10 for processing.

FIG. 5 is a diagram for explaining a processing procedure for recognizing a component position with respect to the image data of FIG. CPU10
Performs the processing of the input image data in accordance with the processing procedure stored in the program memory 11 and recognizes the position and orientation of the component 3. The image data 30 input to the CPU 10 includes three images of a first illumination image 23, a second illumination image 24, and a third illumination image 25 as one component image under a plurality of illumination conditions. Recorded. Here, a case where an image of a chip-shaped electronic component mounted on a surface of a substrate is captured is shown.
In Nos. 3 to 25, the body part 27 and the electrode part 28 of the component are imaged with different brightness or color tone.

First, as a first step, the image data 30
, The body part 27 of the component is extracted from the first field of view 31 including the first illumination image 23 on the left side, and the approximate position (coarse center) of the component is detected. Next, as a second step, a second field of view 32 including the second illumination image 24 at the center of the image data 30 is set from the coarse center data obtained in the first step. Electrode part 2
8 to determine the position of the part. As a third step, a third field of view 33 including the right third illumination image 25 in the image data 30 is set from the coarse center data obtained in the first step, and an image of the component in the third field of view 33 is set. Recognize the posture of the part from With this posture recognition, it is possible to detect an abnormal posture such as a standing suction of the electronic component.

In this case, the first illuminating light from the first illuminating device 5 realizes the first illuminating condition suitable for extracting the body part of the component and detecting the coarse center, and the first illuminating image 23 Is imaged. The second illumination light from the second illumination device 6 realizes a second illumination condition suitable for extracting an electrode part of a component and detecting a detailed position, and a second illumination image 24 is captured. . In addition, the third lighting device 7
3rd suitable for recognizing the attitude of parts by illumination light
Is realized, and the third illumination image 25 is captured. Then, the CPU 10 switches the algorithm for each lighting condition and performs the image recognition processing in the above three steps. In the above-described detection of the coarse center, the detailed position, and the posture, each position information can be detected by using a conventionally known algorithm. In the present embodiment, by processing images captured under three illumination conditions, the position and orientation of the electronic component can be more accurately recognized simultaneously.

[0032]

As described above, according to the present invention, the position of an object can be quickly recognized by capturing and inputting an object image of the object under a plurality of different lighting conditions in one image. The effect that can be obtained is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an image input device according to an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram for explaining an exposure time and a light emission time in the embodiment.

FIG. 3 is a time chart showing output timings of an exposure signal and a light emission signal in the embodiment.

FIG. 4 is an explanatory diagram illustrating an example of an image of a component captured in the present embodiment.

FIG. 5 is a diagram illustrating a processing procedure for component position recognition with respect to the image data of FIG. 4;

[Explanation of symbols]

 Reference Signs List 1 uniaxial stage 2 component suction nozzle 3 component 4 CCD camera 5, 6, 7 illumination device 8 A / D circuit 9 image memory 10 CPU 11 program memory 12 work memory 13 exposure control circuit 14 illumination control circuit 15 pulse counter

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Claims (3)

[Claims] An imaging unit configured to image an object; an illumination unit configured to illuminate the object under a plurality of illumination conditions; an object moving unit configured to move the object within an imaging area of the imaging unit; An imaging control unit that performs exposure control of the imaging unit; and an illumination control unit that performs light emission control of the illumination unit. The object under a plurality of illumination conditions based on the control of the imaging control unit and the illumination control unit. An image input apparatus characterized in that a subject image is captured and input in one image. 2. The image pickup means includes an image pickup device capable of arbitrarily controlling an exposure time by an external exposure signal. During a certain period, exposure control is performed such that an exposure signal is output to perform exposure in the imaging unit, and the illumination control unit outputs a light emission signal when the object is moving in an imaging area of the imaging unit. 2. The image input device according to claim 1, wherein the light emission control is performed so that the lighting unit emits light at different positions under different lighting conditions. 3. The object moving means has a one-axis stage for moving the object one-dimensionally in an imaging area of the imaging means, and the one-axis stage detects a position of the object. A linear scale for the, the lighting means, has a plurality of lighting devices that emit illumination light under different lighting conditions, the lighting control means, based on the output of the linear scale of the uniaxial stage, The image input device according to claim 2, wherein one of the plurality of lighting devices emits light when the object is located at two or more predetermined light emitting positions.