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Kwabena Agyeman, 03/13/2012 04:38 pm


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Typical Uses

One of the primary uses of the CMUcam2 is to track or monitor colors. The best performance can be achieved when there are highly contrasting and intense colors. For instance, it can easily track a red ball on a white background, but it would be hard to differentiate between different shades of brown in changing light. Tracking colorful objects can be used to localize landmarks, follow lines, or chase a moving beacon. Using color statistics, it is possible to monitor a scene, detect a specific color or do primitive motion detection. If the camera detects a drastic color change, then chances are something in the scene changed. Using “line mode,” the CMUcam2 can act as an easy way to get low resolution binary images of colorful objects. This can be used to do more sophisticated line following that includes branch detection, or even simple shape recognition. These more advanced operations would require custom algorithms that would post process the binary images sent from the CMUcam2.

Typical Configuration

The most common configuration for the CMUcam2 is to have it communicate
to a master processor via a standard RS232 serial port. This “master processor”
could be a computer, PIC, Basic Stamp, Handy Board, Brainstem or
similar microcontroller setup. The CMUcam2 is small enough to add simple
vision to embedded systems that cannot afford the size or power of a standard
computer based vision system. Its communication protocol is designed to
accommodate even the slowest of processors. If your device does not have
a fully level shifted serial port, you can also communicate to the CMUcam2
over the TTL serial port. This is the same as a normal serial port except that
the data is transmitted using non-inverted 0 to 5 volt logic. The CMUcam2
supports various baud rates to accommodate slower processors. For even
slower processors, the camera can operate in “poll mode”. In this mode, the
host processor can ask the CMUcam2 for just a single packet of data. This
gives slower processors the ability to more easily stay synchronized with the
data. It is also possible to add a delay between individual serial data characters
using the “delay mode” command. Due to the communication delays,
both poll mode and delay mode will lower the total frame rate that can be
processed. Frame resolutions are not affected by delay mode or baud rate as
they were in the original CMUcam.

CMUcam2_A.JPG - Picture A (23.3 kB) Kwabena Agyeman, 03/14/2012 06:48 pm

CMUcam2_B.JPG - Picture B (26.3 kB) Kwabena Agyeman, 03/14/2012 07:27 pm

CMUcam2_C.JPG - Picture C (47.3 kB) Kwabena Agyeman, 03/15/2012 06:33 pm