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Update 3/26/13

March 27, 2013

A few updates, summarizing our meeting on Sunday:

1. The Hokuyo is dead for all intents and purposes. I’ve send an email to the SICK Group requesting a donation. I will also be emailing the guy that the RAS IGVC group from 2010 talked to get their Hokuyo fixed. In the meantime, Frank will be assembling an array of inexpensive sonar sensors in case we can’t get the Hokuyo fixed or replaced. It has been shown in simulation that the robot does not require very many beams to perform well.

2. Cruz sent me a list of five companies to talk to about getting a camera. Of those, GoPro and Allied Vision have responded with a hopeful note. Still talking with them.

3. There is a number things to do that don’t involve software. I’ve compiled a spreadsheet of them. The three people who are mainly contributing to these are Chris Davis, Cruz, and Josh Bryant. Some other folks have started helping, including Blake and Han. If anyone else would like to help please check out that list and then ask Chris D, Cruz, Josh B, Frank, or I for details.

4. For the last two weeks Lucas has made no progress on vision, as seen here

5. I’ve been testing out some vision-only obstacle avoidance using the same reactive agent that was used to process the Hokuyo scan. The jist is to take a binary image that contains obstacles (output from Frank and Lucas’s work in vision), transform it to correct for perspective, transform it again into a log-polar image (which is basically a plot of angles versus ln(distance)), and divide that into zones and determine the distance from the front of the robot to obstacles detected in the image. The results are published to /scan. Originally we were considering using ray tracing to simulate scans (inspired by these guys), but our method is easy to code and can use optimized OpenCV/CUDA function calls.

The process of taking an image and creating 10 simulated Hokuyo beams is currently very slow, running at 2 Hz. It was written in Python, so hopefully porting it to C++ will improve this. From testing, the reactive agent still performs reasonably well despite image processing slowness, although its overall performance is very dependent on the camera’s mounting and angle of the lens. The reactive agent has no memory, so the robot may run over an obstacle if it falls out of the camera’s view. The camera needs to be pointed almost directly downward, with the Hokuyo just below the picture.


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