Page 159 - Introduction to Autonomous Mobile Robots

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Figure 4.28 Chapter 4
The CMUcam sensor consists of three chips: a CMOS imaging chip, a SX28 microprocessor, and a
Maxim RS232 level shifter [126].

Figure 4.29
Color-based object extraction as applied to a human hand.

processor within the mobile robot. Intel Corporation’s computer vision library is an opti-
mized library for just such processing [160]. In this spirit, the CMVision color-tracking
software represents a state-of-the-art software solution for color tracking in dynamic envi-
ronments [47]. CMVision can track up to thirty-two colors at 30 Hz on a standard 200 MHz
Pentium computer.
The basic algorithm this sensor uses is constant thresholding, as with Cognachrome,
with the chief difference that the YUV color space is used instead of the RGB color space
B
when defining a six-constraint bounding box for each color. While , G , and values
R
encode the intensity of each color, YUV separates the color (or chrominance) measure
from the brightness (or luminosity) measure. represents the image’s luminosity while U
Y