JP2001208692A - Method for controlling illumination - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling illumination capable of automatically dealing with changes in picture quality caused by changes in gloss, for enhancing the accuracy of inspection and saving the labor needed for the inspection. SOLUTION: The method for controlling illumination is used for an illumination control device including a camera 1, an image processor 2 for processing images picked up by the camera 1, a control and process device 3 determining a controlling voltage according to data processed by the image processor 2, and a light source device 5 which turns on according to the controlling voltage. The image processor 2 determines from the images picked up the total of gray level values of picture elements in a certain designated range or all picture elements, and divides the total by the number of picture elements in the designated range or the number of all the picture elements to determine an average gray level value, which is then sent to the control and process device 3. On receiving the average gray level value from the image processor 2, the control and process device 3 compares the average gray level value with a desired gray level value and raises the controlling voltage when it is dark; when it is bright, the device lowers the controlling voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an illumination control method of an illumination control device used for image processing inspection using a CCD camera.

[0002]

2. Description of the Related Art Conventionally, a housing appearance inspection for inspecting a housing of a home electric appliance for flaws, a liquid crystal lighting inspection for inspecting a liquid crystal lighting pattern, and a component set for inspecting a mounting state of components on a printed circuit board. Inspection of electronic components and electrical products such as inspection, tablet packaging inspection to check the presence / absence of packed tablets, and bottling (liquid level) inspection to measure the liquid level of bottled liquid, packaging box Inspection of foods and medicines such as stamping on packaging, marking inspection of packaging box to check whether product number is correct, meter needle indication angle inspection to detect needle position and angle of speedometer,
Automation of inspection / measurement for inspection of automobile / machine processing such as inspection of casting part processing / assembly position measurement to measure the position of screw holes machined into casting parts, crest number of molding screws, burr inspection of molding screws, etc. -To save labor, an image processing technique using a CCD camera is used. In a conventional image processing inspection, a light source device containing a halogen lamp and a light guide containing an optical fiber are provided. The light guide is attached to the light source device, and the light irradiation side of the light guide is covered. The object to be inspected is illuminated toward the object to be inspected, and the CCD camera is configured to obtain a more uniform and clear image.

[0003]

However, when inspecting a component having a metal terminal, such as a connector or an electronic component, the plating applied to the metal terminal may have a luster depending on the temperature, humidity, etc. on the inspection day. When the inspection is performed with the light source device always set at a constant brightness (brightness), the inspection accuracy is not stable due to the change in image quality due to the change in gloss, and the illumination is changed every time the inspection is performed. There is a problem that the brightness (luminance) of the image must be adjusted. The present invention has been made in view of the above-described problems, and has as its object to automatically respond to a change in image quality due to a change in gloss, thereby improving an inspection system and saving labor in inspection. An object of the present invention is to provide a lighting control method.

[0004]

According to the present invention, there is provided an image pickup device such as a CCD, an image processing device for processing an image picked up by the image pickup device, and an image processing device for processing the image picked up by the image processing device. A control processing device that determines a control voltage based on the obtained data, and a lighting control method used in a lighting control device including a lighting device that lights up according to the control voltage, wherein the image processing device includes the imaging device. From the image
Obtain the sum of the gray values of any specified range or all pixels, divide the sum by the specified range or the total number of pixels to obtain the average gray value, and transmit the average gray value to the control processing device. The control processing device receives the average grayscale value from the image processing device, compares the average grayscale value with the target grayscale value, and increases the control voltage when the image is dark, and increases the control voltage when the image is bright. Reduce the voltage.

[0005] According to the second aspect of the present invention, a first aspect is provided.
The lighting control method according to the above, wherein the magnitude of the change in the control voltage is obtained by dividing a value obtained by subtracting a current average gray level value from an average gray level value of an arbitrary target by an arbitrary parameter, and dividing the value by an arbitrary parameter. The value obtained by multiplying the current control voltage value and the current control voltage value are added, and the value is set as a new control voltage value.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a lighting control device used in a lighting control method according to the present embodiment will be described in detail with reference to FIG. FIG. 1 is a configuration diagram of a lighting control device according to the present embodiment. As shown in FIG. 1, a lighting control device according to the present embodiment is a camera 1 having a built-in image sensor such as a CCD.
And an image processing device 2 for processing an image captured by the camera 1 and data processed by the image processing device 2.
And a control processing device 3 for determining a control voltage to the light amount automatic correction device 4. Further, an automatic light amount correction device 4 for determining a correction control voltage for keeping the light source device 5 at a constant brightness (luminance), a light source device 5 having a built-in halogen lamp, and receiving light from the light source device 5 And a light guide 6 for illuminating the object to be inspected. The illumination device is composed of the automatic light amount correction device 4, the light source device 5, and the light guide 6.

A camera 1 having a built-in image sensor such as a CCD
For example, a full-frame shutter video camera such as FC300 of TAKEX Corporation is used, and an analog video output terminal of the video camera is connected to the image processing device 2 via a video signal cable. Image processing device 2
Is, for example, B110P, B410 of Matsushita Electric Works, Ltd.
Use P or the like. The image processing apparatus 2 is equipped with a gray-scale image memory so that an image can be taken from a camera for inspection or a program can be created as needed. Here, the grayscale image memory is a memory capable of storing grayscale data, and in the above-described apparatus, image data of 512 pixels horizontally and 480 pixels vertically is divided into 256 gradations per pixel (pixel). (8 bits).

The image processing apparatus 2 also has an arithmetic function, and performs various arithmetic processing on the image processing data.
The calculation result can be output to the control processing device 3 via S-232C. The control processing device 3 is C
A computer comprising a PU, an RS-232C interface, and a D / A boat, which inputs a calculation result from the image processing device 2 via the RS-232C,
To calculate the control voltage value, and apply the control voltage of the calculated voltage value from the built-in D / A board to the automatic light amount correction device 4, and the automatic light amount correction device 4 The corrected control voltage is applied to the light source device 5.

The automatic light amount correction device 4 is, for example, a MORI
A reference fiber for feeding back light (luminance) emitted from the light source device 5 is attached using MHF-T03 manufactured by TEX Corporation, and the control voltage from the control processing device 3 is corrected. The correction control voltage is applied to the light source device 5 and the light source device 5
The light emitted from the light source device 5 is detected via the reference fiber attached to the control device, and when the brightness is lower than the set brightness, a voltage higher than the control voltage is applied. Feedback control is performed by applying a voltage smaller than the voltage to achieve desired brightness (luminance).

The light source device 5 is, for example, an MHF-D100LR manufactured by Moritex Corporation, and can achieve a desired brightness (luminance) by a correction control voltage from the control processing device 4. Light guide 6
Comprises a tube 6a and a substantially ring-shaped light guiding portion 6b. The tube 6a incorporates an optical fiber for guiding light from the light source device 5, and the light guiding portion 6b includes an optical fiber along the inside thereof. Is connected to the optical fiber in the tube 6a. The optical fiber illuminates the object to be inspected.

Next, a lighting control method according to the present embodiment will be described in detail with reference to FIG. 2A and 2B are flowcharts showing a lighting control method according to the present embodiment, wherein FIG. 2A is a flowchart of the image processing apparatus, and FIG. 2B is a flowchart of the control processing apparatus.

As shown in FIG. 2A, the image processing device 2
Captures an image captured by the camera 1 into a built-in gradation image memory via a video signal cable (step S1). Next, from the image, for example, one side is 10
An arbitrary specified range, such as 0 pixels, is specified, the sum of the gray values of all the pixels included in the specified range is calculated, and the total is divided by the number of pixels included in the specified range to obtain an average gray value. (Step S2), and RS-232
The average gray value is output to the control processing device 3 via C (step S3).

As shown in FIG. 2B, the control processor 3
Then, an average gray value is input from the image processing apparatus 2 via the RS-232C (step F1), and the average gray value is compared with a preset target gray value. In the case of a dark state indicating a smaller value (step F2), the control voltage is increased to increase the brightness of the halogen lamp of the light source device 5 (step F2).
3) Compare the average gray value with the target gray value. If the average gray value indicates a value larger than the target gray value and the display is in a bright state (step F4), the brightness of the halogen lamp of the light source device 5 is increased. , The control voltage is reduced (step F5).

As for the control voltage, a value obtained by subtracting the current average gray value from the target average gray value is divided by an arbitrary parameter k as shown in the equation (1), and the value is added to the current value. The value multiplied by the control voltage value is added to the current control voltage value, and that value is used as a new control voltage value. Here, the arbitrary parameter k is arbitrarily determined by the inspector so that the average gray value approaches the target average gray value quickly.
By changing this parameter k, it can be applied to various test objects.

## EQU1 ## Control voltage value = Current control voltage value + Current control voltage value × (Target average gray value−Current average gray value) / k (1)

[0015]

As described above, according to the first aspect of the present invention, when inspecting a component having a metal terminal such as a connector or an electronic component, the plating applied to the metal terminal is inspected. Even if the gloss changes slightly depending on the temperature, humidity, etc. on the day of the test, the average gray value (illuminance) of the illuminated area
Is adjusted automatically, so that the inspection accuracy is stable and
Since it is not necessary to manually adjust the brightness (luminance) of the illumination, it is possible to achieve an effect of saving labor.

According to the second aspect of the present invention, the first aspect is provided.
In addition to the effects of the described invention, there is an effect that the target average grayscale value can be quickly approached.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a lighting control device according to an embodiment.

FIGS. 2A and 2B are flowcharts illustrating an illumination control method according to the embodiment, wherein FIG. 2A is a flowchart of an image processing apparatus, and FIG. 2B is a flowchart of a control processing apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 camera (imaging device) 2 image processing device 3 control processing device 5 light source device (illumination device) 6 light guide (illumination device)

Claims (2)

[Claims] An image pickup device such as a CCD, an image processing device for processing an image picked up by the image pickup device, a control processing device for determining a control voltage based on data processed by the image processing device, An illumination control method used in an illumination control device including an illumination device that is turned on in accordance with the control voltage, wherein the image processing device is configured such that, from the captured image, any specified range or all pixels, Find the sum of the gray values,
The sum is divided by the designated range or the total number of pixels to obtain an average gray value, and the average gray value is transmitted to the control processing device, and the control processing device calculates the average gray value from the image processing device. An illumination control method comprising receiving and comparing the average grayscale value with a target grayscale value, and increasing the control voltage when dark, and decreasing the control voltage when bright. 2. The magnitude of the change of the control voltage is obtained by dividing a value obtained by subtracting a current average gray value from an arbitrary target average gray value by an arbitrary parameter, and dividing the value by a current control voltage. The lighting control method according to claim 1, wherein a value obtained by multiplying the value and a current control voltage value are added, and the value is used as a new control voltage value.