National Instruments IMAQ Vision for Measurement Studio - Manual (Page 39)

Chapter 3 Grayscale and Color Measurements
© National Instruments Corporation 3-13 IMAQ Vision for LabWindows/CVI User Manual
Ignoring Learned Colors
Ignore certain color components in color matching by replacing the
corresponding component in the input color spectrum array to –1. For
example, by replacing the last component in the color spectrum with –1,
color matching ignores the color white. By replacing the second to last
component in the color spectrum, color matching ignores the color black.
To ignore other color components in color matching, determine the index
to the color spectrum by locating the corresponding bins in the color wheel,
where each bin corresponds to a component in the color spectrum array.
Ignoring certain colors such as the background color results in a more
accurate color matching score. Ignoring the background color also provides
more flexibility when defining the regions of interest in the color matching
process. Ignoring certain colors, such as white color created by glare on a
metallic surface, also improves the accuracy of the color matching.
Experiment learning the color information on different parts of the images
to determine which colors to ignore. For more information about the color
wheel and color bins, see Chapter 14, Color Inspection, in the IMAQ Vision
Concepts Manual.