4.4 Using color vision
Introduction to color vision
PickMaster PowerPaccan either be used with monochrome or color cameras. The
difference between the two is that an image acquired with a color camera represents
each pixel with three 8-bit values (decimal 0-255) instead of only one 8-bit value
for monochrome (grayscale) images. In a monochrome image the 8-bit value
represents the gray level from white to black, whereas in a color image the three
values represent the content of three separate color channels. These three channels
represent red, green, and blue (color space RGB) or hue, saturation, and intensity
(color space HSI). Which color space to work with, depends on the content of the
image.
Color spaces
When working with RGB the color of each pixel is represented by its content of
red, green, and blue. The numerical representation is straightforward for the three
base colors - red (255, 0, 0) green (0, 255, 0), and blue (0, 0, 255). However, it can
be difficult to understand the composition of other mixed colors.
HSI is a color space that is more easily translated to the human perception of
colors.
• Hue: The location of the color on the on the electromagnetic spectrum. See
graphic below.
• Saturation: The purity of the color.
• Intensity: The brightness of the color.
Because the hue spectrum wraps around (both 0 and 255 represent red), it is
suitable to display it as a circle.
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Application manual - PickMaster® Twin - PowerPac 289
3HAC064218-001 Revision: B
© Copyright 2021 ABB. All rights reserved.
4 Working with PickMaster PowerPac
4.4 Using color vision
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