Roomba Robot Upgrade » Laser Rangefinder

Its Done!

howard chen — Fri, 20 Feb 2009 07:08:52 +0000

The Webcam Laser Rangefinder portion of the USAR Sim robot is all wrapped up for the time being. Sorry that the source code is saved as a PDF. There is no other way to upload it.

Final Report- This is the final report which has been submitted as a honors project thesis.

Image Processing API Source Code- Please note that the distance was calculated using a power regression line, not the method outlined in the final report.

Robot Interface- This is the source code written in the VB scripting module of Roborealm to maintain a distance of 50 inches away from an object.

-Howard

Happy Halloween!

howard chen — Fri, 31 Oct 2008 19:38:10 +0000

The rangerfinder algorithm was calibrated. Measurements of pixel from center were taken every five inches from around 2 to eight feet. A power curve was fitted to the data and produced error that was less than 10%. Code should be released sometime next week.

Microsoft Excel Macros

howard chen — Wed, 29 Oct 2008 08:41:59 +0000

I never knew that one could write code for Microsoft Excel until last year. The macros are mostly used to automate repetitive tasks and perform complex calculations. (It could also be used to make music videos. Check out http://www.youtube.com/watch?v=h9_YkXHCkgA)

Since a spreadsheet is made out of individual cells, the spreadsheet itself could be looked upon as an array. Programming in VBA could be done very quick and dirty. All the good programming practices learned in introductory computer programming courses could be thrown out the window (Sorry to make you cry, Prof. Thomas) Heck, variables besides arrays do not need to be defined. More importantly, numbers could be seen exactly where they go when cells are being manipulated, and the code could be stepped through with ease. Once the algorithm has been developed, then it could be re-written in whatever language that is needed.

-Howard

Socket Interface

howard chen — Mon, 27 Oct 2008 18:50:27 +0000

The java version of the sample code was downloaded and recompiled and works like a charm after some initial compiling issues. Since it is a socket connection, it allows the image to be processed on another computer if needed. Now all that is needed is to modify the program to do what we needed. The image comes as one gigantic one-dimensional array.. i.e. image_array(1st pixel blue, 1st pixel green, first pixel red, 2nd pixel blue, 2nd pixel green, 2nd pixel red,..) so the array might need to be converted into a 2d array to make coding the algorithm less challenging. But adding this addition step might slow down the processing.

-Howard

Laser Rangefinder progress

howard chen — Sun, 26 Oct 2008 17:55:31 +0000

The plan is to use the webcam and a laser to determine how far an object is from the robot. We wanted to use a horizontal laser line so multiple distance measurements could be made from each frame. The laser line proved to be too faint for the camera to detect it, even when various sets of filters are applied. A budget of 30 dollars was given to find a new laser that is bright enough for our purposes. A quick search proved that there were two options available, 5mW lasers, which is the one being used, or a 200mW laser diode off a DVD burner with no options in between. After further research, a 200mW laser proved to be a little too dangerous for our needs. If you’re curious on the capabilities of a 200mW laser, check out http://www.instructables.com/id/Laser-Flashlight-Hack!!/

For now, the line generating lens is removed from the laser so initial development of the image processing algorithm could begin.

We currently trying to implement the “webcam based DIY laser rangefinder” available at http://www.pages.drexel.edu/~twd25/webcam_laser_ranger.html The algorithm for finding the red dot is to detect the brightest-colored red pixel in the picture. Since there are no filters in Roborealm that fit our needs, a separate filter must to be created. Writing a program for roborealm allows us to focus on image processing and not worry about the webcam interface.

-Howard