DIY Laser levelling using webcam and laser level

[Sasquatch]

Hi John.
My action cam lost lenses in shooting accident (air rifle ricochet).
Flare with lenses is an result of partial reflection on each layer of glass/ plastic beam is passing trough.
My action cam had a infrared filter behind the lenses.
Sensor is about 3x4 mm 1080p gives higher pixel density than 2 mm wide VGA sensor. Should be good.

Can't find any lasers with single cylinder lense. No Dewalt dw088 on ebay UK in acceptable price. Any cheap laser recommendations ?
Edit 1:

Figured out easy and cheap way of testing projected line straightness.
Method requires roughly straight surface, aluminium extrusion should do. Surface must only be flat within sensor measurement area.
line laser
pointer laser
2x camera sensors set 90 degrees to each other.
first camera is following pointer aiming along the beam
second camera is following projected line
With some excel magic we can deduct straightness of projected laser line independently of any beam errors.
Given we can get 3-4 microns resolution on both sensors accumulated measurements arrors should be below 0.01mm in worst case ->just a gut feeling, no real maths behind it so feel free to correct me. That should be more accurate than any straight edge one could buy, as 0.01mm over, say 3 meters, is waay beyond din 874/0. and sag on wire could be greater than 0.01mm too?

Edit 2:
Software feature request:
Can we have adjustable capture resolution,since higher res cameras have bigger sensors allowing wider beams and/or wider measurements range?
Or at least run in maximum supported resolution, whichever is easiest.
Also when requesting VGA stream from 1080p sensor camera firmware is scaling each frame introducing errors.

Edit 3:
Created pull request on GitHub with more resolutions possible.
Unfortunately i can't figure out how to add menus to change resolution nor how to pass resolution via command line parameters.
Just edit settigs.java and rebuild to required resolution, supported are 320x240,640x480,800x600, 1280x720 and 1920x1080.
Hope that @devmonkey don't mind and will add settings menu in free time.