Surveyor Robotics Journal
   



email:
support@surveyor.com

web:
Surveyor Corporation

rss:
Subscribe

Archives
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
Februray 2006
January 2006

        
Sat, 30 Aug 2008
Sentience Stereo Vision Software Version 0.1 posted for Surveyor SVS

This initial release of Sentience Stereo Vision Software for Surveyor SVS contains algorithms for camera calibration, sparse edge/corner based stereo correspondence and a dense disparity map.

The software is written in C# and has been built by the author on Windows using Visual Studio 2005 or GNU/Linux systems using MonoDevelop. I was able to build the project on Mac OS/X 10.4 (PPC) after installing Mono.

By the way, you will find a number of interesting articles about stereo vision on the main Sentience Project web page.

Posted Sat, 30 Aug 2008 19:06 | HTML Link | see additional stories ...

Sun, 24 Aug 2008
Upgrading an SRV-1 robot to stereo vision ...

Here is a brief description of the process to upgrade an SRV-1 Blackfin robot to stereo vision. We unsolder the motor leads and battery wire from the original motor controller or combo motor/radio board, remove the circuit boards, then check the wire lengths to make certain they will reach the connectors on the underside of the SVS controller. More often than not, we do have to lengthen those wires, especially if we are mounting a pan/tilt head to the robot base.



Note that we have added connectors to the motor and power wires, using Jameco 100766 connector pins with Jameco 100812 plastic blocks. Also, we have added somewhat taller standoffs to keep the antenna cable and 32-pin headers clear of the robot base. For the original dual-motor bases, we add 7/16" standoffs. For the new quad-motor base, we would use 1" standoffs.

The Blackfin and Matchport should be running at 2500kbps with latest firmware (srv-blackfin-081408.zip at time of this post). The final step is to move the Blackfin camera, Matchport radio, and dipole antenna cable from the original boards and base to the SVS board before mounting the SVS to the robot base. In some cases, we also have to change the lens on the original camera board from 6.5mm to the newer 3.5mm wide angle lens in order to match the second Blackfin camera.

Here is the end result of an upgrade ...





It is actually the second upgrade for this particular robot, which belongs to RoboRealm. It started life as an SRV-1 ARM7 with Zigbee a couple of years ago for use in their original SRV-1 support, and was upgraded to Blackfin with WiFi almost a year ago for development of their updated SRV-1 Blackfin support. Now it is headed back to them for development of stereo vision algorithms, and we look forward to the results !

Posted Sun, 24 Aug 2008 16:05 | HTML Link | see additional stories ...

Wed, 20 Aug 2008
Surveyor SVS (stereo vision system) - first experiments with automated color segmentation for stereo disparity calculations

While others are working on much more sophisticated stereo disparity algorithms using host computing power, I thought we might be able to build some basic matching functions into the Blackfin firmware using simple color matching for correlating objects between the separate views. The key to this approach is to segment the images into a minimal set of colors that can be used for simple image comparisons.

Color segmentation is an interesting research problem which has led to the definition of a variety of color spaces, as discussed here and here, as well as a variety of feature processing models, as described here. One of the goals in creating the SRV-1 Blackfin and the SVS was to provide an easily accessible platform for experimenting with the color segmentation challenge.

As described above, a simple approach would minimize the number of colors in the corresponding stereo images and then look for matches. Below, you will see the original stereo pair (scaled down for this display), a 16 color segmentation that uses 4 luminance and 4 chrominance levels (2 bits Y, 1 bit U, 1 bit V - "211"), and a 16 color segmentation that uses 4 U and 4 V levels (2 bits U, 2 bits V, and no luminance component - "022").







The 211 approach seems to provide reasonable feature definition, but correlation of colors between left and right images isn't actually so great. The 022 approach doesn't seem to be making very good use of the range of colors, but the feature correlation almost looks usable. So the next step is to find a segmentation of the UV-only space that more efficiently maps actual colors. Along these lines, we divided the U and V color spaces into 16 segments each, and then built a tool to display the U vs V histogram in 2D.

The next step is to define a segmentation that looks for clustering or local maxima in the 2D histogram. So stay tuned ...

Posted Wed, 20 Aug 2008 19:39 | HTML Link | see additional stories ...

Mon, 11 Aug 2008
Progress with SRV-1 Blackfin Stereo Vision System

Sentience stereo vision software developer Bob Motram has been working for a few weeks with one of the prototype SRV-1 Blackfin stereo vision systems, and he has already developed a slick calibration procedure to correct for wide-angle lens distortion, as described here -
        http://streebgreebling.blogspot.com/2008/08/surveyor-project-calibration.html





Initial tests of stereo correspondence procedures have started, as discussed here -
        http://streebgreebling.blogspot.com/2008/08/visual-disparity.html



You can track Bob's progress via his blog or via his source code.

Posted Mon, 11 Aug 2008 17:01 | HTML Link | see additional stories ...


Live Internet control of SRV-1 Blackfin Robots - BP Explorer

This is a fantastic demo of SRV-1 robot remote control through the Internet - www.bpexplorer.com.au









The images above show some fixed camera views of the "set" as well as snapshots captured by one of the robots. Five robots are available for control at any time, though sometimes the queue to access the site is quite long. The BP Explorer demo is intended to highlight some of BP's green technologies, including the solar panels that are used to recharge the robots. Kudos to the amazing job Ogilvy New Zealand did in putting this together for BP Australia.

Posted Mon, 11 Aug 2008 15:34 | HTML Link | see additional stories ...