Hardware manual

Impact Reference Guide Contrast
3-101 Datalogic Automation Inc.
To set up the tool:
1. Draw the Shape List ROI over the color area you want to find.
2. Click the Train button. The tool finds the R, G and B values of the color in the Shape List ROI and put
it in the Trained Color value.
Wherever the Trained Color is located in the RGB color space, the Maximum Allowed Color Difference is
the radius of a sphere around that color. A pixel in an image is considered out of tolerance when it is further
from the Trained Color than the Maximum Allowed Color Difference (i.e. it is outside that sphere). The
value is calculated using the CMC Color Difference. The CMC color difference is a complex formula that
attempts to compensate for variation in human eye sensitivity across the RGB color space. It maps RGB dif-
ferences into “just perceptible color differences.” The Color Checker tool averages the color in an area and
calculates the CMC difference just once versus the trained color.
The units are greyscale steps from 0 to 100.
Contrast
In the Feature Finding and Flaw Detection Drawers
The Contrast tool checks the pixels within an ROI and calculates the percentage or area of pixels that are
outside and inside the Threshold Range. If the calculated range or area is inside or outside the user-defined
range, the tool sets the Passed output to True. The In Range and Out of Range tests are mutually exclusive
and the tool always Fails if they are both enabled.
Input Name What it is
Input Image Linked Image
Click the plus sign to access greyscale versions of the image that you
can link into other greyscale image processing tools. These images are
similar to the image you get if you use a color filter or color light with a
greyscale camera. See “Color Image Sub-Properties” on page 3-35.
Tool Origin The tool’s origin relative to the entire image space.
Shape List The desired region of the image to check.
Trained Color The Red, Green, and Blue values of the trained color. (0-100)
Maximum Allowed
Color Difference
This is the maximum difference allowed between the Average Color in
the inspected image area and the Trained Color.
Output Name What it is
Average Color The Red, Green, and Blue values of the average color in the Shape List.
(0-100)
Actual Color Differ-
ence
The difference between the Trained Color and the Average Color, in the
RGB color space.
Color In Tolerance If True, the Actual Color Difference is less than the Maximum Allowed
Color Difference.