edge detection with digital photography

[tomhale]

Hi, does anybody know if there is a way to automatically detect an edge and measure that edge in a computer. For instance, what I'm after would be for a computer to process a picture of say a box and have the computer automatically calculate its width by detecting its edges and measuring the number of pixels between these two edges. I'm not sure if it's possible but would be interested in hearing anybody's ideas.

 

[Ls3D]

3D artist use photogrametry to derive 3D models from images, so the delta between two edges in pixel space should not be too tough to code,... got any C+ friends?

BTW - I used to run a realtime camera tracking system that did edge detection and triangulation to track live broadcast cameras in studio, all very proprietary and expensive part of virtual set work.

-Shea

 

[roadkill]

Try an automatic edge detecter.

 

[Garbz]

It is most definitely possible. The guy two stalls down from me at this years UQ Innovation Expo was using a webcam, edge detection, and a checkerboard on the floor to calculate a subjects height. Got me right to within 3cm as well.
Another guy also used edge detection for horizon mapping in a project to steer rockets. His worked perfectly and could even map the planet horizon in scenes from the BBC documentary "planet earth". He apparently started with little more than the wikipedia entry http://en.wikipedia.org/wiki/Edge_detection

 

[Moglex]

Edge detection is certainly possible and in some cases fairly straight forward but the problem is that there are no general purpose solutions.

You cannot just go and buy an edge detection program as you could a photo editor or music player.

How easy it is to produce the software would depend on various factors concerning the environment, lighting, object placement and factors such as: are the edges (in your example) always parallel, are they always aligned to within a few degrees, are there likely to be confusing patterns present on the object or in the background that the software has to be coded to ignore?