I'm trying to build a laser distance sensor using triangulation (With this as my main inspiration, Webcam Based DIY Laser Rangefinder).

Laser distance measurement using triangulation

My plan is to use a linear CCD array as the imager, such as the Toshiba TCD132D, for detecting the absolute distance to an object. I'll basically try to make a higher resolution version of the Parallax TSL1401-DB.

Due to my limited knowledge of optics and lenses, i have a hard time figuring out what the optical setup should be. Note that the distance sensor should be able to measure distances from 20 cm to 5 m, with a precision of +/- 0.5 cm.

I assume that the object would cause the laser beam to have a diffuse reflection, and that some kind of convex lens should be used to focus the diffuse reflections on a few pixels in the linear array.

I would prefer an off the shelf board mounted lens, but since the linear array sensor is 1.4 cm wide, none of the lenses i have found would be a good fit. Does any of you have any suggesting regarding which optics to use, and preferably any literature or tutorials that would make me understand this topic a bit clearer?

  • $\begingroup$ I don't work with optics but have a copy of the Edmund Scientific catalog which is full of hardware and useful information. Start on their website. $\endgroup$ – Transistor Jul 11 '16 at 19:06
  • $\begingroup$ This is a shopping question. VTC. $\endgroup$ – Sparky256 Jul 11 '16 at 19:27
  • $\begingroup$ Check the Ray transfer matrix description. It is a good starting point, although the paraxial approximation may not apply in your case. Have a look at optical aberrations e.g.: spherical aberration, comma, and curvature. Optics can get quite complicated, if you start including diffraction and other wave related properties. It generally reduces to a non-convex optimization problem, which is NP hard. If you can do some approximations, the complexity of the problem can be reduced. I guess what you can do is assume the angle is small. $\endgroup$ – user110971 Jul 11 '16 at 20:13

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