User`s manual

G-12
Glossary
G
[W]
Ë Window
The IV-S30 captures images using CCDs, which are the light sensitive elements in the camera. The IV-
S30 may capture more than one target image to be measured for image processing, and it may cap-
ture images not required for measurement. In these cases, a window is used to pick out just the de-
sired target for measurement. The area inside the window will contain the object to be measured and
the areas outside the window will be ignored.
Object to be measured
Objects outside the designated
measurement area
Window
[γ]
ËË
ËË
Ë γ positive correction
Used when the mid gray level is too low.
ËË
ËË
Ë γ negative correction
Used when the mid gray level is too high.
255
255
Input image gray level
Output image gray level
255
255
Input image gray level
Output image gray level
( Example for adjustment )
An example of adjustment is shown below, using a white object on a black background. When
the dotted line in the window is converted to a binary image, if the lower limit is set higher, the
black part in the binary image will become larger. If the lower limit is set lower, the white part
will become larger. Increase and decrease the lower limit value, find the value at which the
white part in the binary image starts growing and the value at which the black part starts
growing. Then set the lower limit at the value halfway between these points. This will ensure
reliable operation.
White
Inspection image
Horizontal coordinate
of the dotted line
Changing the lower limit threshold value
The size of the white area changes
depending on the threshold value setting.
As the value increases,
the black part grows larger.
Stable range
As the value decreases,
the white part grows larger.
0
255
White
*
*
Black
Lower limit threshold
If the stable range in the lower limit threshold
value is less than 20, (actual measurement)
measurement errors ma
y
occur.