# Laser Scanning - Geometry and Triangulation

1. Jul 22, 2010

### Krb686

I want to make a laser scanner using the triangulation method, but I would like some verification on the geometry of it.

The device is circular, with a line laser pointing inwards to the center, and a webcam offset a certain arc length along the circle. You have the distance from the laser to the webcam.

Now, the issue I have is the orientation of the line laser. If the laser is positioned with the line traveling top to bottom, then you know the angle at the laser, and I assume you can find the angle at the webcam by using software and finding a ratio of where the laser appears to the camera, taking into account its field of view. (aka, if the laser appears halfway between the center and the left side, and the field of view is 120 degrees, then the angle would be at 30 degrees?) So perhaps no problems here, but what if the laser is positioned horizontally?

Originally , I thought of this because it would allow the scanner to have a greater range of detection for crevices and inward shapes on the object.

But, if the laser is positioned horizontally, then you no longer know the angle at the laser, because it is a line, correct? So, would you need markers on the opposite inner side of the circle to measure the angle correctly?

Here is a picture of this situation with the laser horizontal.

http://img251.imageshack.us/img251/8861/24092436.png [Broken]

Last edited by a moderator: May 4, 2017