	Vision Systems

Inspection Functions

Area sensor (binary conversion)

This function detects the area by counting the number of white or black pixels within the measurement window. With color processing, the area is detected by counting the number of extracted or unextracted color pixels.

Output when the detection color is set to black

Output when the detection color is set to white

Dimension measurement

Various dimensions are measured by setting a window on the image and measuring the distance between the detected edges.

Inner diameter measurement		Outer diameter measurement

Blob

The group of pixels with the same intensity range within the binary (black and white) image is called a "blob". The quantity of blobs, and features such as the area and gravity point, are measured by the blob mode.

Features Measured by Blob

Center of Gravity

The center of gravity of the blob is measured using the X-Y coordinate.

Area

The number of pixels in the blob is measured.

Principal Axis Angle

The principal axis angle from the horizontal (X) axis is measured
within the range of ±90°.

Feret Diameter

The lengths in X and Y directions of the circumscribed quadrangle of the blob are measured.

Perimiter

The perimiter of the blob is measured.

Roundness

The perfect circle is represented in the number of 1,000 to measure the roundness of each blob.

Detection of Scratches and Flaws (STAIN)

Detection Principleof Stain
(when detecting direction is set to X)

1.	By moving a segment of arbitrary size within the inspection area by 1/4 of the size (amount of movement), the mean intensity is measured.

2.	The difference between the maximum and minimum intensity within the 4 directional segments including the observation segment ( in the figure to the right) is measured. This value becomes the "stain level" of the observation segment.

3.	If the stain level exceeds the preset threshold, the observation segment is counted as a stain. This count will be reflected in the inspection result, called the "stain amount".

Then, move the observation segment by 1/4 of the size again and repeat the procedures from 1 to 3.

Detection of Scratches and Contamination with the STAIN function

Reference

When detection directions are specified to X and Y (two-dimensional) directions

If X and Y are specified, the difference between the maximum and minimum intensity within the 16 segments (4 segments in X direction x 4 segments in Y direction including the observation segment) is measured.

Using the STAIN function in two dimensions

Advantages of Stain Algorithm
in Comparison with the Standard Method Using Binarization

	Because a grayscale picture is directly processed, there is no need to configure binarization, etc., according to the work.
	Because the difference in the value in shade as compared with the surrounding is used, but not the absolute concentration value, the measurement is hardly affected by the changes in illumination intensity.

Detection of scratches on the surface of cast part



Initial condition		Inspection by scratch detection: The scratch can be detected even when illumination intensity is lowered.



		Inspection by blob: The binarized image changed due to lowered illumination intensity and a false detection is made.

Trend Edge Position

The specified segment in the edge detection area is scanned and maximum/minimum values and mean value of each point are output. This is effective for the measurement of maximum/minimum external diameter and detection of protruding parts.

When the measurement area is in rectangular shape

When measurement area is in circular shape

Trend Edge Position with a rectangular area

Trend Edge Position with a circular area

※	Rotate the segment towards the trend direction for edge detection.

	If highly accurate position detection is required, reduce the segment size.
	In order to shorten the processing time, reduce the shift width of the segment (= amount of movement).
	The trend direction signifies the direction towards which the segment is moved.

Intensity Inspection

Because contrast (intensity) mean value, maximum/minimum values, and deviation value within the measurement area can be measured, it can also be used for illumination intensity fluctuation-resistant area measurement or high-speed scratch detection.

When temperature difference is large

When temperature difference is small

Contrast Inspection with a large temerature difference

Contrast Inspection with a small temperature difference

	Mean intensity of window 1: 50
	Mean intensity of window 2: 200
	Intensity difference: 150

	Mean intensity of window 1: 150
	Mean intensity of window 2: 200
	Intensity difference: 50

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