WO2004029548A1

WO2004029548A1 - Apparatus and method for capturing images from a camera

Info

Publication number: WO2004029548A1
Application number: PCT/KR2003/001715
Authority: WO
Inventors: Ssang-Gun Lim; Ee-Bae Choi; Sang-Yoon Lee; Sang-Hyun Cho; Tae-Wahn Kim; Suk-June Jang
Original assignee: Intek Plus Co., Ltd
Priority date: 2002-09-26
Filing date: 2003-08-25
Publication date: 2004-04-08
Also published as: KR20040026927A; AU2003253462A1; CN1685198A; KR100495120B1

Abstract

An apparatus and method for capturing picked-up images at a high speed.The apparatus includes a CCD (Charge Coupled Device) camera for picking up images of an object placed at a pickup area and outputting the picked-up images; a synchronous signal generator for generating an illumination control signal every time a frame enable signal outputted from the CCD camera is detected; an illumination controller for controlling an operation of turning on light sources surrounding the pickup area at different positions in response to the illumination control signal; and an image capture unit for capturing an image outputted from the CCD camera every time the frame enable signal is detected, and transmitting the captured image to an image signal processor.

Description

APPARATUS AND METHOD FOR CAPTURING IMAGES FROM A CAMERA

Technical Field

The present invention relates to a system for optically measuring geometry of an object, and more particularly to an apparatus and method for capturing images picked up from a camera at a high speed.

Background Art

With the development of electronic engineering and mechanical engineering, the miniaturization and precision of electronic and mechanical components has been enhanced. In order for processing and manufacturing states of the small- sized electronic and mechanical components to be appropriately confirmed, an operation for precisely measuring their dimensions, geometry and surface roughness must be carried out . For example, the dimensions, geometry, laser marking states and surface roughness associated with semiconductor wafers being' electronic components and minute patterns of processed ICs (Integrated Circuits) cannot be precisely measured using a known non-contact type measuring device. Furthermore, a minute scar can be caused on an object's surface by a probe tip of a contact type surface-roughness measuring device using a probe and hence information of the object's surface cannot be appropriately produced.

Devices for measuring the dimensions and geometry of the small-sized electronic and mechanical components include a two-dimensional measuring device based on a non-contact optical method and a three-dimensional measuring device. The two-dimensional measuring device optically produces data of the object's dimensions using light irradiated from a light source. The three-dimensional measuring device makes light irradiated from a light source in the form of a reference pattern, projecting the light to the object to be measured, compares the reference pattern with light modified according to the geometry of the object, and optically measures the geometry of the object. A single unit into which the two- dimensional measuring device and the three-dimensional measuring device are integrated has been developed and supplied so that the two-dimensional and three-dimensional devices are selectively or alternately used. However, the conventional devices for optically measuring the geometry of the object have problems that images picked up from a CCD (Charge Coupled Device) camera cannot be captured at a high speed, and a time needed to test products on manufacturing lines cannot be reduced. These problems will be described in detail with reference to FIGS. 1 and 2 .

FIG. 1 is a block diagram illustrating an optical geometry measuring system for carrying out a conventional image capturing operation. The optical geometry measuring system includes a CCD camera 10 for picking up and outputting an image of an object in response to an input of a trigger signal from an image capture unit 25 described below; and a plurality of light sources 40 mounted at different positions for adjusting illuminations on different surfaces of the object to be measured and tested. For example, the optical geometry measuring system for measuring a manufactured semiconductor package includes an illumination mount having a dome form at the top of a pickup area on which the object is placed. The object is picked up on the basis of a structure in which the CCD camera 10 is located at a center of the illumination mount having the dome form in a vertical direction of the object. In the case of the conventional semiconductor package, the system sequentially carries out a laser mark inspection, lead inspection, pin 1 inspection, etc. according to a program. On/off operations of the light sources 40 mounted on different positions of the dome must be controlled according to objects to be inspected or measured. An operation for controlling the light sources 40 is carried out by an illumination controller 30, and the illumination controller 30 controls the light sources 40 in response to trigger signals generated from the image capture unit 25 provided in a computer system 20. For reference, the CCD camera 10 is implemented with a digital CCD camera, model name CV-M4+, made by Japan's JAI, and picks up digital images corresponding to 24 frames per second to output the picked-up digital images .

The image capture unit 25 provided in the computer system 20 captures the images outputted from the CCD camera 10, and transmits the captured images to an image signal processor 27. The image capture unit 25 generates and outputs trigger signals to synchronize the illumination controller 30 with the CCD camera 10, and captures the images outputted from the CCD camera 10. In response to the trigger signals, the light sources 40 are turned on and the images are captured. The reason is that the picked-up images must be captured while the light sources 40 are turned on to pick up the images of the surfaces of the object to be measured.

For reference, the image signal processor 27 receives the captured images and carries out an image signal processing operation for the captured images to output a result of the image signal processing operation so that a display unit 29 can display the captured images. A controller 23 receives an image-based measurement initiation command from an operator through a data input unit 21 and then transfers the measurement initiation command to the image capture unit 25.

In the above-described optical geometry measuring system, the CCD camera 10 picks up images to output the picked-up images in response to trigger signals inputted from the image capture unit 25. The image capture unit 25 captures and transmits the outputted images after the trigger signals are generated, and then subsequent trigger signals are newly generated. The CCD camera 10 can output a maximum of 24 frames per second. However, there is a drawback in that the image capture unit 25 captures only 16 or 17 frames per second.

Thus, the optical geometry measuring system cannot capture the picked-up images at a high speed. Furthermore, there is another problem in that a time required for testing an object to be measured cannot be reduced.

Disclosure of the Invention

Therefore, the present invention has been made in view of the above problem, and it is one object of the present invention to provide an apparatus and method for capturing picked-up images at a high speed, which can accelerate a speed of capturing the picked-up images in an optical geometry measuring system. It is another object of the present invention to provide an apparatus and method for capturing picked-up images at a high speed, which can capture the picked-up images at the maximum frame rate capable of being supported by an image pickup device.

It is yet another object of the present invention to provide an apparatus and method for capturing picked-up images at a high speed, which can reduce a time required for testing an object using an optical geometry measuring system.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating an optical geometry measuring system for carrying out a conventional image capturing operation;

FIG. 2 is a block diagram illustrating an apparatus for capturing picked-up images at a high speed in accordance with an embodiment of the present invention;

FIG. 3 is a flowchart illustrating an operation of a synchronous signal generator 56 shown in FIG. 2; and FIG. 4 is a timing diagram illustrating signals generated from the apparatus for capturing picked-up images at a high speed in accordance with an embodiment of the present invention.

Best Mode for Carrying Out the Invention

In accordance with one embodiment of the present invention, the above and other objects can be accomplished by the provision of an apparatus for capturing picked-up images at a high speed, comprising: a CCD (Charge Coupled Device) camera for picking up images of an object placed at a pickup area and outputting the picked-up images; a synchronous signal generator for generating an illumination control signal every time a frame enable signal outputted from the CCD camera is detected; an illumination controller for controlling an operation of turning on light sources surrounding the pickup area at different positions in response to the illumination control signal; and an image capture unit for capturing an image outputted from the CCD camera every time the frame enable signal is detected, and transmitting the captured image to an image signal processor. Preferably, the synchronous signal generator may comprise: an internal memory in which mapped illumination control data is stored so that the operation of turning on the light sources arranged at the different positions is controlled according to order of detection of frame enable signals .

In accordance with another embodiment of the present invention, the above and other objects can be accomplished by the provision of a method for capturing picked-up images at a high speed in an optical geometry measuring system that captures the images picked up by a CCD (Charge Coupled Device) camera and enables a display unit to display the captured images, comprising the steps of: detecting a frame enable signal outputted from the CCD camera; generating an illumination control signal to turn on light sources surrounding the pickup area at different positions every time the frame enable signal outputted from the CCD camera is detected; capturing an image outputted from the CCD camera in synchronization with the illumination control signal; and carrying out a signal processing operation for the captured image and enabling the display unit to display a result of the signal processing operation. Now, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings . In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 2 is a block diagram illustrating an apparatus for capturing picked-up images at a high speed in accordance with an embodiment of the present invention; FIG. 3 is a flowchart illustrating an operation of a synchronous signal generator 56 shown in FIG. 2; and FIG. 4 is a timing diagram illustrating signals generated from the apparatus for capturing picked-up images at a high speed in accordance with an embodiment of the present invention. Referring to FIG. 2, a digital CCD (Charge Coupled

Device) camera 10, model name CV-M4+, made by Japan's JAI, picks up digital images of an object placed at a pickup area and then outputs the picked-up digital images . The digital CCD camera 10 can output scan images at a rate of 24 frames per second. Every time an image of the object placed at the pickup area is picked up, the digital CCD camera 10 generates and outputs a frame enable signal FEN. The digital CCD camera 10 communicates with an image capture unit 55 through an LVDS (Low-Voltage Differential Signaling) protocol . A computer system 50 includes a data input unit 51 such as a keyboard and a mouse. An operator can input a geometry measurement initiation command for an object such as a final semiconductor package through the data input unit 51. This command is inputted into a controller 53. When the controller 53 controlling an overall operation of the computer system 50 receives the geometry measurement initiation command through the data input unit 51, the controller 53 transfers the geometry measurement initiation command to the image capture unit 55 and a synchronous signal generator 56.

The image capture unit 55 captures images outputted from the CCD camera 10 in response to detection of the frame enable signal FEN outputted from the CCD camera 10, and outputs the captured images to an image signal processor 57. The frame enable signal FEN is bypassed to the synchronous signal generator 56. The image capture unit 55 is enabled in response to the geometry measurement initiation command inputted from the controller 53. The image signal processor 57 receives images captured by the image capture unit 55, carries out an image signal processing operation for the captured images to generate image signals capable of being displayed on a display unit 59 such as a monitor, and then outputs the image signals.

After the measurement initiation command is inputted, the synchronous signal generator 56 generates an illumination control signal upon detecting the frame enable signal FEN outputted from the CCD camera 10, and transmits the illumination control signal to an illumination controller 30. The illumination controller 30 controls an on/off operation of light sources, surrounding a pickup area, arranged at different positions of an illumination mount according to the illumination control signal.

In FIG. 2, the synchronous signal generator 56 and the image capture unit 55 are separated. A single logic 60 can be configured so that the function of the synchronous signal generator 56 can be performed within the image capture unit 55.

In accordance with the embodiment of the present invention, an image-capture apparatus sequentially controls the light sources to sequentially carry out a laser mark inspection, lead inspection, pin 1 inspection, etc. for an object, e.g., a semiconductor package. According to the order of detection of frame enable signals, mapped illumination control data is stored in a memory so that the light sources arranged at different positions can be controlled. This memory is provided in the synchronous signal generator 56.

In other words, the synchronous signal generator 56 generates the illumination control signal with different illumination control data items every time a frame enable signal is detected after the synchronous signal generator 56 is enabled in response to a geometry measurement initiation command inputted from the controller 53. The illumination controller 30 can carry out a control operation so that the light sources arranged at the different positions are turned on. The illumination control signal includes location information of the light sources to be turned on. The location information of the light sources must vary with the order of the detection of the frame enable signals. As the modification of the embodiment, the synchronous signal generator 56 can simply generate an illumination control signal every time a frame enable signal is detected, and the illumination controller 30 can carry out a control operation so that the different light sources can be turned on every time the illumination control signal is inputted.

The above-described embodiments are characterized in that the light sources arranged at the different positions are turned on every time a frame enable signal is detected.

An operation of the apparatus for capturing picked-up images at a high speed will now be described in detail with reference to FIGS . 3 and .

An operator desiring to measure the geometry of an object, inputs a geometry measurement initiation command through the data input unit 51 after a plurality of semiconductor packages are placed on a transfer device such as a conveyor. Of course, the operator must set the CCD camera 10 to a pickup mode in advance. For reference, the pickup mode is an operating mode for picking up images of the object placed within the pickup area at the maximum frame rate and outputting the picked-up images . In accordance with the embodiment of the present invention, the CCD camera 10 can output the picked-up images at 24 frames per second. When the picked-up images can be outputted, activated frame enable signals are outputted. The controller 53 transfers a geometry measurement initiation command φ to the image capture unit 55 and the synchronous signal generator 56 in response to the above- described geometry measurement initiation command if the object is placed at the pickup area. Upon receiving the geometry measurement initiation command at step 70, the synchronous signal generator 56 is enabled and determines whether the first frame enable signal FEN is detected through the image capture unit 55 at step 72.

If the first frame enable signal is detected, the synchronous signal generator 56 generates and outputs the first illumination control signal stored in the memory at step 74. The generated illumination control signal is inputted into the illumination controller 30 and will be used for turning on the light source arranged at a predetermined position. The image capture unit 55 is synchronized with the frame enable signal FEN detected after the geometry measurement initiation command is inputted and begins to capture picked-up images at a frame rate of the CCD camera 10. In other words, the first image is captured in response to the first frame enable signal detection, and the captured image is unnecessary since the image has been captured before programmed light sources are turned on. However, an image captured according to the following second frame enable signal FEN is a normal image picked up in a state where at least one light source is turned on in response to the first illumination control signal. The reason is that the light source is turned on according to the illumination control signal generated after the first frame enable signal FEN is detected. When an image of the object is picked up at a point of turn-on time, an output image from the CCD camera 10 is captured in response to the second frame enable signal .

The CCD camera 10 picks up images of the object at a rate of 24 frames per second and outputs the picked-up images. The synchronous signal generator 56 detects the frame enable signal FEN at a time of picking up images of the object, and then the light sources are sequentially controlled at the frame rate. Upon capturing the images at an output frame rate of the CCD camera 10, the image capturing operation is carried out from the second image at W

the frame rate of the CCD camera.

Thus, at steps 76 to 80, the synchronous signal detector 56 repeatedly generates an illumination control signal every time the frame enable signal is detected after the first frame enable signal. A point of termination time associated with the illumination control signal generation is determined by the number of inspection items to be tested. Where the number of inspection items of one semiconductor package is "5" , the synchronous signal generator 56 will proceed to step 82 after six illumination control signals programmed in advance are completely generated.

At the above step 82, the controller 53 is notified that the one semiconductor package has been completely measured, such that a new object is transferred to the pickup area by the transfer device. If a termination command is not received at step 84, the synchronous signal generator 56 returns to the above step 70. The above steps 72 to 82 are repeatedly performed according to a result of the determination made as to whether or not the geometry measurement initiation command is received.

For reference, an FEN signal shown in FIG. 4 indicates a frame enable signal outputted from the CCD camera 10. Symbols (2) and denote an illumination control signal and an image capture time-point, respectively. As shown in FIG. 4, it can be seen that an operation of generating the illumination control signal and the image capturing operation are carried out in synchronization with the operation of detecting the frame enable signal FEN. Furthermore, it can be seen that the light source is turned on by the illumination control signal (2), and then a pick-up image is captured when a subsequent frame enable signal generated immediately after the illumination control signal is detected.

Thus, the present invention enables the light sources to be sequentially turned on according to the frame rate of the CCD camera 10. Furthermore, the present invention enables the operation of capturing the picked-up images to be carried out according to the frame rate of the CCD camera 10. Consequently, the system of the present invention can capture images at a high speed in comparison with a conventional system in which an operation of turning on the light sources and an operation of capturing images are performed according to synchronous signals.

Industrial Applicability

As apparent from the above description, the present invention can accelerate a speed of capturing images picked up at a frame rate of a CCD (Charge Coupled Device) camera since an operation of turning on light sources and an W 20

operation of capturing the picked-up images are controlled in synchronization with a frame enable signal.

Furthermore, the present invention can reduce a time of testing an object and improve a yield of manufacturing since a speed of capturing picked-up images can be accelerated.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope of the invention. Accordingly, the present invention is not limited to the above-described embodiments, but the present invention is defined by the claims which follow, along with their full scope of equivalents.

Claims

Claims :

1. An apparatus for capturing picked-up images at a high speed, comprising: a CCD (Charge Coupled Device) camera for picking up images of an object placed at a pickup area and outputting the picked-up images; a synchronous signal generator for generating an illumination control signal every time a frame enable signal outputted from the CCD camera is detected; an illumination controller for controlling an operation of turning on light sources surrounding the pickup area at different positions in response to the illumination control signal; and an image capture unit for capturing an image outputted from the CCD camera every time the frame enable signal is detected, and transmitting the captured image to an image signal processor.

2. The apparatus as set forth in claim 1, wherein the synchronous signal generator comprises : an internal memory in which mapped illumination control data is stored so that the operation of turning on the light sources arranged at the different positions is controlled according to order of detection of frame enable W

signals .

3. The apparatus as set forth in claim 1 or 2, wherein the synchronous signal generator and the image capture unit are enabled in response to a geometry measurement initiation command.

4. An apparatus for capturing picked-up images at a high speed in an optical geometry measuring system, comprising: a CCD (Charge Coupled Device) camera for picking up images of an object placed at a pickup area and outputting the picked-up images; an image capture unit for generating an illumination control signal every time a frame enable signal outputted from the CCD camera is detected, and capturing an image outputted from the CCD camera in synchronization with the illumination control signal; an illumination controller for controlling an operation of turning on light sources surrounding the pickup area at different positions in response to the illumination control signal; and an image signal processor for carrying out a signal processing operation for the image captured by the image capture unit, and outputting a result of the signal processing operation to a display unit.

5. The apparatus as set forth in claim 4, wherein the image capture unit comprises : an internal memory in which mapped illumination control data is stored so that the operation of turning on the light sources arranged at the different positions is controlled according to order of detection of frame enable signals .

6. A method for capturing picked-up images at a high speed in an optical geometry measuring system that captures the images picked up by a CCD (Charge Coupled Device) camera and enables a display unit to display the captured images, comprising the steps of: detecting a frame enable signal outputted from the CCD camera; generating an illumination control signal to turn on light sources surrounding the pickup area at different positions every time the frame enable signal outputted from the CCD camera is detected; capturing an image outputted from the CCD camera in synchronization with the illumination control signal; and carrying out a signal processing operation for the captured image and enabling the display unit to display a result of the signal processing operation.

7. The method as set forth in claim 6, wherein the illumination control signal comprises location information of the light sources to be turned on, the location information of the light sources varying with order of detection of frame enable signals.