JP3237248B2 - Image processing method and image processing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing method and an image processing apparatus used for automatic positioning and inspection of various production facilities and automation equipment including electronic component mounting machines and robots.

[0002]

2. Description of the Related Art In recent years, various types of production equipment such as electronic component mounting machines have been accelerated in terms of the tact time of production of the equipment for the purpose of improving productivity. Among them, an image processing apparatus that captures an image from a CCD camera, in particular, is being rapidly mounted on a production facility and expanded in its application range as a key to increasing the precision, speed, and flexibility of the production facility. When thinking about speeding up equipment based on an image processing device using a CCD camera,
Along with shortening the processing time of the image information, shortening the time required to capture an image into the image processing device (image input) with the CCD camera is also an important factor.

In a normal CCD camera, the time required for transferring one screen (one frame transfer) to various external devices such as an image processing apparatus and a monitor television is fixed at 1/30 second. An exposure time for accumulating charges on the photoelectric conversion surface of the camera is required.

When an image processing apparatus is used in a production facility, an image processing object is moved by some means or an image pickup system such as a camera, a lens, a mirror, or the like is moved to sequentially and continuously supply objects. A method of inputting an image is generally used. In any case, in order to image a target with an imaging device such as a CCD camera, it is necessary to stop a moving object (moving object) for a certain period of time and expose the moving object (moving object) to a photoelectric conversion surface on the CCD . In increasing the speed of production equipment, the stationary time of this moving object (moving body) becomes a major obstacle to improving production tact.

[0005] To address this, the following two techniques are known.
One is. 1) Prior art 1: Using normal continuous lighting, CC
Taking a sufficient exposure time for the photoelectric conversion surface on the D, shuts
A stable image is secured with a normal CCD camera without a data function . 2) Prior art 2: using a strobe or shutter camera
The image of the moving object is frozen by the instantaneous light.

In particular, in the case of the prior art 2, basically, it is not necessary to stop the moving body, but it requires devices such as a strobe and a shutter camera, which is disadvantageous in cost. In addition, imaging with a strobe or a shutter camera has practically a low degree of freedom in the adjustment stage, and often leaves problems in terms of stability of image quality and securing of light amount. Therefore, this application
The invention shall improve the prior art 1, and the prior art 1
A conventional method will be described with reference to FIGS.

FIGS. 5 and 6 show conventional operation timings. FIG. 5 is an operation timing diagram when using a field accumulation type CCD camera, and FIG. 6 is an operation timing diagram when using a frame accumulation type CCD camera.

[0008] Interlaced scanning text such as NTSC
Levi camera has a single screen consisting of only the odd number of scanning lines and an even number
Alternate timing for the remaining single screen consisting only of th
The scanning operation is basically performed. And this odd number
The screen generated from the scan line is called odd field, even
The screen generated from the scan line number is called even field.
And combine both fields into one complete screen.
You. In other words, the field is used for interlaced scanning.
Screen generated from odd-numbered scan lines and even-numbered scan lines
Each of the screens generated from the scan lines is called a single screen.
This is the name of the time. In contrast, a frame is an odd
By combining the number field and the even field ,
All images are generated, but when calling this image
It is a name.

[0009] Field accumulation means that one CCD is stored in the CCD.
Field (exposed)
Output electric signals from the CCD in the next field
For each even and odd field.
To generate TV camera images sequentially by repeating
It is an expression. In contrast, frame accumulation is one frame
Time (that is, 2 fields), the image of the subject
Is exposed to the CCD, and from the CCD in the next field
Performs video output operation on even and odd fields
By repeating for each, the image of the TV camera is sequentially
It is a method of generating.

[0010] From the above operating principle, the field accumulation method
In the equation, 2 is required for exposing one frame (two fields) of an image.
Field exposure time is required, while frame exposure
In the multiplication method, three fields are required for one frame image exposure.
Exposure time is required.

Here, N, which is a television camera standard in Japan,
In TSC, the scanning time of one field (this is 1
Is equivalent to the field exposure time) is 1/6
0 seconds and one frame scanning time (one frame exposure
Is equal to 1/30 second.

[0012] In the conventional method, the time for stopping the movement of the moving body is determined in consideration of the time required for capturing the image, so that the scanning timing of the camera is not monitored.
The main controller that controls the operation of the equipment is waiting for the operation for the time (theoretical value + margin) required for the still image exposure of the CCD camera.

When the CCD camera uses the field accumulation method, the timing shown in FIG. 5 is a theoretical value (ideal value).
Since the stop of the movement of the imaging target is not synchronized with the scanning timing of the CCD camera, the field of the exposure time (the (n-1) th field on the exposure surface) including the timing of the stop of the movement of the imaging target moves. The image in the state where it is
And the image is blurred.
There are no images to be processed, such as
Will be effective. The subsequent exposure is effective when the imaging target is stationary. Since the main controller scanning timing of the camera does not monitor and control the deviation of the moving stop the camera scan by considering the worst case, the above-described image
It is necessary to provide a waiting time of (1 field + 1 field) in order to avoid a defect of a captured image such as a blur . After the waiting time, the image capturing is started, the capturing is performed for a period of one frame, and the movement of the imaging object can be started.

When the movement is started without completely waiting for one frame period, a part of the captured image becomes (n +
2) In the image exposed in the field (the image transferred on the transfer surface as the (n + 2) field), the moving time
May expose the image of the imaging target on the CCD
As a result, image blurring may occur.

Therefore, the movement stop time in the conventional method is 1 field (1/60 second) +1 field ( 1/6)
60 seconds) +1 frame (1/30 seconds) , about 67
ms is the minimum requirement.

When the CCD camera is of the frame accumulation type, the timing shown in FIG. 6 is a theoretical value (ideal value). Since the stop of the movement of the imaging target is not synchronized with the scanning timing of the CCD camera, the frame of the exposure time including the timing of stopping the movement (the (n-1) th frame on the exposure surface)
Frame) is invalid, and the subsequent exposure becomes effective when the imaging target is stationary. Since the main control device does not monitor and manage the camera scanning timing, it is necessary to provide a (1 frame + 1 field) waiting time in consideration of the worst case of the difference between camera scanning and movement stop.

After this waiting time, the image capturing is started, the capturing is performed for one frame period, and the movement of the imaging object can be started. When the movement is started without completely waiting for one frame, a part of the captured image is an image exposed in the (n + 2) th frame on the exposure surface (an image transferred on the transfer surface as an (n + 2) field). May cause blurring. Therefore, the movement stop time in the conventional method is 1 frame (1/30 second) +1 field
(1/60 second) + 1 frame (1/30 second)
A minimum of about 83 ms is required.

[0018]

In the above-mentioned conventional method, at least the field storage system C is used after the moving body stops.
Approx. 67 ms for CD, approx. 83 for frame accumulation type CCD
This requires a stationary time of the moving object of ms, which is an obstacle to speeding up.

The present invention solves the above-mentioned problems, and does not use a device which is disadvantageous in cost such as a strobe or a shutter camera, and has a small number of commercially available CCD cameras.
At least, it is possible to capture a stable image using illumination that is continuously lit during the exposure time of the image to the CCD, and to stop (stop) the image capturing object compared to the conventional image processing method (image input method). It is an object of the present invention to provide an image processing method capable of reducing time.

[0020]

According to the present invention, in order to achieve the above object, the present invention as defined in claim 1 is applied to a field storage.
Or a continuous point at least during the exposure time with the frame accumulation method
CCD camera that captures the image of the imaging target illuminated by the lamp light
An image memory for inputting image information from the camera;
Vertical blanking of the CCD camera by controlling the input of moly
Image scanning timing
An image timing control circuit for detecting the image timing;
Notification of the image scanning timing from the
And a control unit for starting and monitoring the image timing control circuit.
Image processing executed in an image processing apparatus having
In the method, an object to be imaged by the CCD camera is an imaging position.
When the CCD camera reaches the
In the case of the method, after the imaging target reaches the imaging position,
The second vertical blanking of the CCD camera
3rd vertical blanking in case of frame accumulation method
Start image input to the image memory from the timing , and
Do not wait for the end of one frame image input to the image processing device.
In this case, one frame of the object to be imaged on the photoelectric conversion surface of the CCD camera
When the exposure for the camera is completed, the CCD camera or
An image processing method for starting the movement of the image target was adopted.

According to the second aspect of the present invention, there is provided the image according to the first aspect.
An image processing apparatus for performing the image processing method was used.

[0022]

According to the present invention, when a normal CCD camera and continuously illuminated illumination are used, the present invention operates to reliably capture an image of a moving object with the shortest stop time.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image processing apparatus applied to an electronic component mounting machine according to one embodiment of the present invention will be described below with reference to the drawings. 1 and 2 show operation timings of the image processing apparatus in the present embodiment. FIG. 1 is an operation timing chart when a field accumulation type CCD camera is used, and FIG. 2 is an operation timing when a frame accumulation type CCD camera is used. FIG. 3 is a perspective view of a rotary head type electronic component mounting machine,
FIG. 4 is a block diagram illustrating a configuration of the image processing apparatus.

In FIG. 3, 1 is a rotary head for rotating a plurality of nozzles, 2 is a nozzle for sucking electronic components from a component supply unit and mounted on a printed circuit board, and 3 is a component for supplying electronic components to a mounting machine. A supply unit, 4 is a printed circuit board on which electronic components are mounted, 5 is a CCD camera for capturing an image of the sucked electronic component into an image processing device, and 6 is a photoelectric conversion of the image of the electronic component sucked by a nozzle. This is a lens barrel unit that reflects on the surface.

In FIG. 4, reference numeral 7 denotes an image processing apparatus of the present invention, 8 denotes an object to be imaged by a CCD camera, and 5 denotes a C
A CD camera, 10 is an image memory for inputting image information from a CCD camera, 11 is an image memory for controlling input,
Processor (controls the image scanning timing of the CD camera 5)
Image timing control circuit to inform the section), 12 a processor (control which controls the activation and monitoring of the image timing control circuit
) , 13 are position detecting means such as a sensor and an encoder for detecting that the imaging target has reached a predetermined imaging position,
Reference numeral 14 denotes a main equipment control unit that controls, monitors, and instructs the operation, communication, and the like of the entire electronic component mounter.

With respect to the image processing apparatus of the electronic component mounting machine having the above components, the mutual relationship and operation of each component will be described with reference to FIGS.

The rotary head type mounting machine shown in FIG. 3 performs an intermittent feeding operation as a basic motion.
The electronic component supplied in step (2) is sucked by the nozzle 2, an image of the electronic component to be imaged is captured by the CCD camera 5 through the lens barrel unit 6 into the image processing device 7, and the position of the electronic component is determined based on the image processing result. A series of operations of mechanically performing the correction and mounting the electronic components on the printed circuit board 4
The operation is performed continuously in accordance with the intermittent rotation of the rotary head 1.

Among the above operations, operations such as suction, mounting, and image processing of electronic components are each processed in parallel (simultaneously). If any one of the operations takes a long time, This determines the overall cycle time (time for simultaneously processing each operation at each operation position). In particular, focusing on the operation of image processing,
When capturing images without using equipment that is disadvantageous in terms of cost, such as a strobe or shutter camera, the CCD with the imaging target stationary for a certain period of time or more
Exposure to the camera is required.

However, in the intermittent feed motion of the rotary head 1 shown in FIG. 3, it is usually difficult to maintain a stopped (stationary) state for more than half of the cycle time. Therefore, in order to speed up the rotational movement of the rotary head (reduce the cycle time), it is necessary to reduce the time required for capturing an image in a stationary state.

For example, in order to realize a cycle time of 0.1 s, it is necessary to capture an image in a stationary state of about 0.05 s (50 ms), which is half of this. The image processing method of the present invention makes this possible by the following method.

The object 8 (the electronic component sucked in this case nozzles), a detection signal outputted image that comes from the position detecting means 13 detected by the position detecting means 13 to the position (timing) to capture, Through the main equipment control unit 14,
Or directly, the processor (control unit) of the image processing device 7
12 to cause the processor to start monitoring the image timing control circuit 11.

In accordance with the operation timing shown in FIG. 1 or FIG. 2, the processor (control unit ) monitors the image timing (through the image timing control circuit) and captures the image.

When the CCD camera 5 is of the field accumulation type, it follows the timing shown in FIG. Basically, the stop of the movement of the imaging object (electronic component) 8 is not synchronized with the scanning timing of the CCD camera 5, so that the exposure time field (the (n-
1) field) is invalid, and the exposure in this field ends when the exposure after the first vertical blanking (the (k-1) th vertical blanking) after the stop of movement is the object to be imaged. Is stationary and enabled.

In the case of field accumulation, one-side (one field) exposure is completed until the next vertical blanking (k-th vertical blanking), that is, the n-th field on the exposure surface, and the next field ( (N +
1) This effective image (still image) from the top of the field)
Transfer to the external device is started. Exposure of the remaining one side (one field) is performed in the (n + 1) th field of the exposure surface, and is then transferred in the (n + 2) th field of the exposure surface.

The image of the n (n + 1) th field on the transfer surface (the image exposed on the exposure surface in the nth and n + 1th fields) is taken into the image processing apparatus in the most efficient manner in terms of time. In the present invention, to achieve this,
The image timing control circuit 11 monitors and detects the second vertical blanking (k-th vertical blanking) after the imaging target has stopped moving, starts image capture from this timing, and further starts image capture. Thereafter, the movement of the imaging target is started after scanning one field. As a result, an object can be imaged with a movement stop of about 50 ms for a maximum of three fields (one field scans in 1/60 second).

When the CCD camera 5 is of the frame accumulation type, it follows the timing shown in FIG. Similarly to the field accumulation method, the stop of the movement of the imaging target (electronic component) is not synchronized with the scanning timing of the CCD camera, and therefore, the exposure time frame (the (nth -1) frame) is invalid, and the exposure of this frame ends in the first vertical blanking (the (k-1) th vertical blanking) after the movement is stopped. The subsequent exposure is effective when the imaging target is stationary.

In the case of frame accumulation, one-side (one field) exposure ends until the next vertical blanking (the (k + 1) th vertical blanking), that is, the n-th frame of the exposure surface. The transfer of this effective image (still image) to the external device is started from the beginning of the next frame (the (n + 2) th frame on the exposure surface). The exposure of the remaining one side (one field) is performed in the (n + 1) th frame of the exposure plane, and is transferred from the head of the (n + 3) th field of the next exposure plane.

The most efficient method in terms of time is to take the image of the n-th and (n + 1) -th fields on the transfer surface (the image exposed at the n-th and n + 1-th frames on the exposure surface) into the image processing apparatus. In the present invention, in order to realize this,
The image timing control circuit 11 monitors and detects the third vertical blanking ((k + 1) th vertical blanking) after the imaging target stops moving, and starts image capture from this timing. After ingestion starts,
After one field scan, the movement of the imaging target is started.

As a result, an object can be imaged with a movement stop of about 68 ms for a maximum of four fields (one field scans in 1/60 second).

As described above, according to the present embodiment, the image timing control circuit stops the image storage in the memory, stops the imaging target, starts the second vertical blanking (in the case of a field storage camera), and executes the third vertical blanking. (In the case of a frame accumulation camera) from the vertical blanking, so that the stop time of the imaging target component can be reduced.

[0041]

As is apparent from the above embodiments, according to the present invention, an ordinary CCD camera and continuous lighting are used.
In the case of the field accumulation method , when the imaging target reaches the imaging position, the second C
The vertical blanking CD camera, when the frame storage mode the third round of the vertical blanking timing Karae
The image input to the image memory is started, and 1
Capture on CCD without waiting for the end of frame image input
Since the exposure of the target image is completed,
Since the movement of the image object can be started , an image of the moving object can be input in the shortest rest (movement stop) time.

[Brief description of the drawings]

FIG. 1 is an operation timing chart when a field accumulation type CCD camera is used in an image processing method according to an embodiment of the present invention.

FIG. 2 is an operation timing diagram when a frame accumulation type CCD camera of the same method is used.

FIG. 3 is a perspective view of a rotary head type electronic component mounting machine.

FIG. 4 is a block diagram showing a configuration of an image processing apparatus according to the method.

FIG. 5 is an operation timing chart of a conventional method when a field accumulation type CCD camera is used.

FIG. 6 is an operation timing chart of the conventional method when a frame accumulation type CCD camera is used.

[Explanation of symbols]

Reference Signs List 5 CCD camera 7 Image processing device 8 Object to be imaged 10 Image memory 11 Image timing control circuit 12 Processor (control unit) 13 Position detecting means

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G01B 11/00-11/30102 G06T 1/00 G06T 1/60 H04N 5/335 H04N 7/18

Claims (2)

(57) [Claims] 1. An image pickup device illuminated by continuous lighting at least during an exposure time in a field accumulation or frame accumulation method.
An image memory for inputting image information from the CCD camera for capturing an image of the object, before controlling the input of said image memory
This is the vertical blanking timing of the CCD camera.
And an image timing control circuit for detecting an image scanning timing has known that, before the said image timing control circuit
In the image processing method executed in the image processing apparatus provided with a control unit that is notified of the image scanning timing and controls the activation and monitoring of the image timing control circuit,
When the imaging target of the CD camera has reached the imaging position, the shooting when the CCD camera is a field accumulation mode
The second CCD after the image target reaches the imaging position
The vertical blanking camera, in the case of frame accumulation method starts image input to the image memory from the third vertical blanking timing, 1 off to the image processing apparatus
Without waiting for the end of the frame image input, the CCD camera
Exposure of one frame of the imaging target to the photoelectric conversion surface is completed.
Then, the movement of the CCD camera or the imaging object starts.
Image processing method for. 2. An image memory for inputting image information from a CCD camera for picking up an image of an image pickup object illuminated with continuous lighting at least during an exposure time in a field accumulation or frame accumulation method, and an input to the image memory. An image timing control circuit capable of controlling and detecting an image scanning timing at which the timing of the vertical blanking of the CCD camera can be known; and informing the image scanning timing from the image timing control circuit and starting the image timing control circuit. An image processing apparatus comprising: a control unit that supervises a monitor; wherein the control unit monitors an image scanning timing of the timing control circuit when an imaging target of the CCD camera reaches an imaging position; Is the field storage method, the second time after receiving the signal When the vertical blanking of the CCD camera is the frame accumulation method, the image input to the image memory is started from the third vertical blanking timing, and the completion of the image input of one frame to the image processing apparatus is not waited. And CC
An image processing apparatus for starting movement of the CCD camera or the imaging target when exposure of one frame of the imaging target to the photoelectric conversion surface of the D camera is completed.