Building a real-time 2D laser range finder

First, a laser line, parallel to the ground, is projected onto the objects to be detected. The camera is mounted above the laser, pointing downwards at the objects on an angle. Next, the logic device continuously scans each line of video data, recording the point in the line where the highest intensity of red was detected. This point corresponds to the distance of the nearest object in that direction, but needs to be corrected using a look-up table. Once each row of data is scanned, the vision system has a list of the distance to the first object along the entire field of view from the camera. This data can then be used to determine which direction to move a robot, or to map out the current environment. Cool!

via Make