JP2003303336A - Method of setting threshold for region extraction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately extract a region from a color image taken by a color camera. <P>SOLUTION: The image taken by the color camera is displayed on a CRT screen, and the region to be extracted is selected by a pointing device. The distribution of the R value, G value and B value of picture elements inside the selected region is measured. The threshold is set easily by a primary threshold determining means for determining a threshold for extracting the region from the measured distribution condition of the R value, G value and B value and by adjusting the threshold obtained by the primary threshold determining means. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention extracts an arbitrary area having predetermined color information from an image obtained by photographing with a color camera, which is used for judging the quality of the final appearance of a printed wiring board. The present invention relates to a region extraction threshold value setting method for extracting an arbitrary region by a method of determining a threshold value for

[0002]

2. Description of the Related Art Conventionally, visual inspection is performed to inspect the final appearance of a printed wiring board after the solder resist printing process and the silk printing process. However, in this visual inspection, an inspection error such as an oversight may occur due to individual differences among the inspectors who perform the inspection, or the inspection accuracy may vary.

For this reason, a printed circuit board inspecting apparatus has been put into practical use in which a printed wiring board is photographed by a camera and automatically inspected by using image processing. However, when inspecting the final appearance of the printed wiring board after the solder resist printing process and silk printing process, the imposition pad
It is necessary to extract the areas of the copper pattern portion such as the land, the silk printing portion, and the solder resist printing portion, and perform the inspection accuracy for each area. Since each area of the copper pattern portion, the silk print portion, and the solder resist print portion has different color information, the area is extracted by various methods using the color information as a feature amount.

[0004]

The image captured by the color camera in the area extraction method is divided into information of R value, G value and B value, and the R value, G value, A method of extracting within the range of the preset threshold for each B value,
From R value, G value, B value for each pixel on the image, hue, saturation,
There is a method of calculating the brightness and extracting it for each pixel on the image within the range of the preset thresholds for the hue, saturation, and brightness, but there are thresholds for the R, G, and B values. In order to set, the operator empirically determines and sets the threshold value, so that the value differs depending on the operator, and it takes a lot of time to determine the value.

The present invention is intended to solve such a problem, and it is easy and accurate to set a threshold value for extracting an arbitrary area having predetermined color information from an image obtained by photographing with a color camera. The purpose is to determine. In addition, the present invention extracts a desired area by a method of determining a threshold value for extracting a desired area having predetermined color information from an image obtained by photographing with a color camera to determine the final appearance of a printed wiring board. An object of the present invention is to solve the problem of each area extraction in the inspection by easily and accurately determining the threshold in the final appearance inspection apparatus for a printed wiring board that determines the quality.

[0006]

A region extraction threshold setting method according to claim 1 of the present invention is a color image photographed by a color camera by a method of extracting an arbitrary region from a color image photographed by a color camera. Is displayed on the CRT screen, an area to be extracted with the pointing device is selected on the image displayed on the screen, and the R value threshold value, G value threshold value, and B value threshold value on the selected area are configured. It is characterized by determining a first-order threshold value.

According to a second aspect of the present invention, there is provided a region extraction threshold value setting method, wherein the R value threshold value, the G value threshold value and the B value threshold value determined by the area extraction threshold value setting method according to the first aspect are CRT.
It is characterized in that the secondary image is adjusted on the screen and the binary images extracted by the respective thresholds are displayed on the CRT screen, and the secondary threshold is determined by adjusting the primary threshold.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is applied to the area extraction parameter setting of the final appearance inspection apparatus for a printed wiring board in the final step of manufacturing the printed wiring board. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a view showing the outline of the arrangement of a final appearance inspection apparatus for a printed wiring board according to this embodiment. This printed wiring board inspection device was created by taking a picture of the printed wiring board after the solder resist printing process and the silk printing process with a color camera, and taking a picture of the created data and a printed wiring board that is considered to be a good product. Master image, CA
An automatic final appearance inspection device for the purpose of automatically inspecting the solder resist of a printed wiring board and each pattern of copper and silk printing by comparing with reference data created from a master image created from D data, Inspection camera 1, confirmation camera 2, control processing unit 3, inspection monitor 4,
It is composed of a confirmation monitor 5, a camera drive unit 6, a stage 7, a drive control unit 8, and the like.

The inspection camera 1 captures an image of a printed wiring board to be inspected and a non-defective printed wiring board image. After the inspection is completed, the confirmation camera 2 captures an image of the defective portion of the detected inspection-target printed wiring board. The control processing unit 3 performs image processing, data processing, mechanical control, etc.
A camera controller 9 that takes in positional information of the stage 7 and sends an inspection signal to the inspection camera 1, an image input / processing unit 10 that processes RGB data of an image captured by the inspection camera, and an inspection used for inspection A data storage unit 11 for storing various data such as reference data and inspection parameters and inspection result data is built in. The inspection monitor 4 performs a man-machine interface such as setting various parameters in the inspection. The confirmation monitor 5 displays a defective portion image of the inspection target printed wiring board taken by the confirmation camera. The camera drive unit 6 moves the camera in the X-axis direction. The stage 7 fixes the printed wiring board to be inspected and the non-defective printed wiring board, and moves in the Y-axis direction. The drive control unit 8 controls the drive of the camera drive unit 6 and the stage 7 according to a command from the control processing unit 3.

The image of the printed wiring board taken by the inspection camera 1 has a copper pattern portion, a silk printing portion, and a solder resist printing portion, and each area is extracted with R, G, and B value thresholds, respectively. The images are inspected with different inspection accuracy.

A method of setting thresholds for R value, G value and B value will be described below. FIG. 2 is a display for setting the primary threshold value. An image of the printed wiring board to be inspected and the non-defective printed wiring board taken by the inspection camera is displayed on the inspection monitor, and the area to be extracted is designated by the pointing device 12.
To select a rectangle using
The maximum value / minimum value of the value, the maximum value / minimum value of the G value, the maximum value / minimum value of the B value, the threshold value of the R value of the area, G
It is stored in the memory as a primary threshold composed of a value threshold and a B value threshold.

FIG. 3 is a display for adjusting and determining the secondary threshold value. Adjust the primary threshold stored in memory,
A RED plane, a GREEN plane, a histogram 13 for each BLUE plane on the CRT screen to determine the secondary threshold, a slider 14 for adjusting the primary threshold,
The primary threshold value display 15 and the extracted image 16 that reflects the primary threshold value determined by the primary threshold value setting method are displayed, and the knob 14a of the slider 14 is operated by the pointing device 17 to display the operated threshold value. The threshold value is adjusted while looking at the reflected extracted image 16.

[0014]

As described above, the present invention solves the problem of extracting each area in an inspection by easily and accurately determining the threshold value for extracting the area. Further, there is an effect that the labor and time can be reduced in the threshold setting work.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a final appearance inspection device for a printed wiring board.

FIG. 2 is an explanatory diagram of primary threshold setting.

FIG. 3 is an explanatory diagram of secondary threshold value setting.

[Explanation of symbols]

1 Inspection camera 2 Confirmation camera 3 Control processing unit 4 Inspection monitor 5 Confirmation monitor 6 camera drive 7 stages 8 Drive control unit 9 Camera controller 10 Image input processing unit 11 Data storage 12 pointing device 13 Histogram 14 Slider 14a Slider knob 15 First threshold display 16 Extracted image 17 pointing devices

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Koichi Yonekura             3-20-1, Tenjin Stock Exchange, Koga City, Fukuoka Prefecture             Inside the Shoga Electric Works Koga Plant F-term (reference) 5B057 AA03 BA02 BA30 CA01 CA08                       CA12 CA16 CB01 CB06 CB12                       CB16 CC01 CE12 DA17 DB02                       DB06 DB09 DC19

Claims (2)

[Claims] 1. A color image photographed by a color camera is displayed on a CRT screen by a method of extracting an arbitrary region from a color image photographed by a color camera, and a pointing device is used on the image displayed on the screen. A region extraction threshold value setting method characterized in that an area to be extracted is selected and a primary threshold value composed of an R value threshold value, a G value threshold value, and a B value threshold value on the selected area is determined. 2. An R value threshold value, a G value threshold value, and a B value threshold value, which are determined by the area extraction threshold value setting method according to claim 1, are set to C.
Area extraction characterized by adjusting on the RT screen and displaying a binary image extracted at each threshold value on the CRT screen and adjusting the primary threshold value to determine the secondary threshold value Threshold setting method.