|Surveyor Robotics Journal|
Sat, 24 Oct 2009
Feature article on Surveyor SVS (stereo vision system) in Nov/Dec Robot Magazine
The latest issue of Robot Magazine has an excellent in-depth five page review of the Surveyor SVS, starting on page 30.
The author, Harry Mueller, explores many of the capabilities and limitations of the system in its current form, including stereo correspondence, neural net, picoC, RoboRealm, and other features. As Harry notes, "The SRV-1 and its most recent incarnation, the SVS, can best be characterized as a very sophisticated and evolving toolkit for vision experimentation". His conclusions are right on the money as well, though you will have to read the article to find out what he wrote.
Wed, 14 Oct 2009
New tool for SRV-1 Blackfin color blob searches
There is a new C library for AVR processors called "WebbotLib" that has added support for the SRV-1 Blackfin camera as an alternative to CMUcam. In the process of adding the SRV-1 support, the developer realized that we had no good tools for analyzing and selecting colors used for blob searches, so he wrote a new Java-based console, as described here.
This console is particularly useful for identifying colors and color bin ranges that will be used in blob searches. As seen above, I worked out a color range for the "red" of a spool of wire, and the actual blob outlines are displayed. The console is designed to work with serial rather than network interfaces, as this is the typical configuration for the SRV-1 Blackfin camera when connecting to an AVR-class processor.
Note that WebbotLib is an open source project - sourceforge.net/projects/webbotavrclib
Sat, 10 Oct 2009
Embedded Stereo Correspondence on the Surveyor SVS Blackfins
Just posted on The Streeb-Greebling Diaries, this is a very helpful explanation and demonstration of stereo correspondence on the Surveyor SVS (stereo vision system) based on code from the Sentience Project.
A video showing the results of the stereo correspondence algorithm embedded on the Surveyor SVS. This is running on two Blackfin DSPs with synchronised frame capture. Larger red spots correspond to objects closer to the cameras. The big metal object is the left shoulder of the GROK2 robot.
There is some "pollution" where matching of horizontally oriented features causes bad matches in the surrounding region of the image, but most of the time the spot sizes are inversely proportional to range. There is always a certain amount of noise in the matching, but if the features are converted into sensor models and used to update an occupancy grid then this tends to cancel out with repeated overlapping observations.
Ordinarily horizontally oriented features can't be matched, at least by sparse feature based correspondence methods, but it does seem to be a useful heuristic to apply similar disparities to horizontally oriented features which are in the neighbourhood of matched vertically oriented ones. Even though it sometimes produces errors, this helps to provide more information about the structure of the environment which can be useful when creating maps or avoiding obstacles.
Thu, 08 Oct 2009
Direct interface to SRV-1 Blackfin / SVS from browsers and smart phones (iPhone, Google Android, etc) -
As first discussed last month, we have extended the httpd support in the SRV-1 Blackfin / SVS firmware for a more robust browser interface and some extended user functionality. As shown below, we have continued with the idea of image mapping the robot controls, but now we have a graphical overlay that can be turned on/off to show the actual controls.
There is still work to be done with the stability of the connections, but this seems to work quite well with iPhone and Google Android smart phones. We look forward to tester feedback.