« Previous - Version 33/44 (diff) - Next » - Current version
Kwabena Agyeman, 03/13/2012 04:24 pm


Wiki

Quick Links

Typical Uses

The CMUcam can be used to track or monitor color. The best performance can be achieved when
there are highly contrasting and intense colors. For instance, it could 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 CMUcam 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 CMUcam. As is the case with a normal digital camera, this type of processing
might require a computer or at least a fast microcontroller.

Typical Configuration

The most common configuration for the CMUcam 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 CMUcam is small enough to add simple vision to
embedded systems that can not 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 CMUcam over the TTL serial
port. This is the same as a normal serial port except that the data is transmitted using 0 to 5 volt logic. The
CMUcam supports various baud rates to accommodate slower processors. For even slower processors, the
camera can operate in “poll mode”. (See “PM” command pg 22.) In this mode, the host processor can ask
the CMUcam 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. (See “DM” command pg 19.) Due to the communication delays, both poll
mode and delay mode will lower the total frame rate that can be processed.

botfrontright.jpg - Robot Front Right (6.9 kB) Kwabena Agyeman, 02/16/2012 12:47 pm

camboard.jpg - Camera Board (11.8 kB) Kwabena Agyeman, 02/16/2012 12:47 pm

camfront.jpg - Camera Front (14.2 kB) Kwabena Agyeman, 02/16/2012 12:47 pm

camfrontright.jpg - Camera Front Right (7.4 kB) Kwabena Agyeman, 02/16/2012 12:47 pm

CMUcam1_A.JPG - Picture A (22.1 kB) Kwabena Agyeman, 03/14/2012 06:18 pm

CMUcam1_B.JPG - Picture B (25.5 kB) Kwabena Agyeman, 03/14/2012 06:18 pm