Date: Thu, 15 Jun 2006 02:24:16 -0500 (CDT)
Subject: code keeps shrinking
X-UID: 177

I am rewriting all of the onboard robot control system code except for the 
microcontroller firmware. This is now properly a mixture of C and 
object-based C++ using templates. Given all of the previous work, it 
constitutes "version 3" which is typically the "good one" (it takes three 
releases of any product before it matures). Right now, it looks like the 
entire system might fit under 2000 lines of code. That includes both 
source and header files.

It's kind of difficult to explain what is going on. But I'm sure this is 
orthodox real-time design that I've just rediscovered through much trial 
and error. At a very high level, data flows through processes by means of 
pipes. System state is in the data flowing through the system at any time. 
Each process is itself stateless. In a way, it reminds me of the stateless 
client-server design patterns encountered in n-tier web application 
servers.

For a first cut, I figure that the 3 cluster kMeans RGB histogram 
Stanford's robot used in the DARPA GC is overkill. I'll just try 1 cluster 
(average and standard deviation) with a grayscale intensity histogram. I'm 
hoping that by using a circular image buffer (ergodic assumption - time 
average and spatial averages are approximately equal) the road 
segmentation will be just good enough. Another reason for trying a simple 
approach first is to maintain a good frame rate. The system is operating 
close to its limits at all times as the computers are very underpowered.