Hardware manual

Impact Reference Guide Color Blob
3-97 Datalogic Automation Inc.
Major Length
The Major Length is the length of the major axis of an ellipse having the same moments of inertia about the
major and minor axes as the blob.
Minor Length
The Minor Length is the length of the minor axis of an ellipse having the same moments of inertia about the
major and minor axes as the blob.
Color Blob
In the Feature Finding Drawer
The Color Blob tool finds areas within an ROI based on the Trained Color. If it is set to find Out Of Range
areas, it finds areas that vary from the Trained Color. If it is set to find In Range areas, it finds areas that
match the Trained Color. Impact software uses a 24-bit color system.
NOTE: The tool’s execution time depends on the image resolution. Very high resolution images may take a
long time.
Where the Blob tool has a minimum and maximum threshold range, the Color Blob tool has a Trained Color
and a Maximum Allowed Color Difference from the Trained Color.
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. If the tool is set to detect Out Of Range, a pixel in an image is con-
sidered out of range when it is further from the Trained Color than the Maximum Allowed Color Difference
(i.e. it is outside that sphere). If there are multiple colors in the training region, the color with the most pixels
is trained. The other colors are ignored and do not affect the trained color. The Color Blob tool calculates the
color difference of every pixel versus the trained color and needs a simple formula for speeds sake, so it uses
the Euclidean difference.
The units are greyscale steps from 0 to 100, just like the monochrome Blob tool threshold range, so values of
5 to 10 are typical settings.
Major Axis
Length
Minor
Axis
Length