DIY Laser levelling using webcam and laser level

[Michael Gilligan]

Afternoon all.

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Anyway the purpose of this post is to describe a new app I put together today for laying the master rail straight. I decided it would be easier to use a taut wire rather than the laser for this and a cheap USB microscope.
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The microscope is attached to a hiwin carriage and the new app accurately locates the wire allowing you to zero the tool then reports the error as you slide the carriage back and forth.
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Nothing new in the process that other people have performed other than the app that lets you achieve excellent accuracy with little effort.
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The wire locating algo is quite different from the laser gausian model and seems extremely robust.
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Cheers, Joe

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With apologies for absence ... it's been a while since I was here :

That sounds like a great development, Joe
I obviously need to read the next couple of pages, but please let me join those requesting that you share the App

MichaelG.
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Edit: Just off to grab that code

[devmonkey]

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With apologies for absence ... it's been a while since I was here :

That sounds like a great development, Joe
I obviously need to read the next couple of pages, but please let me join those requesting that you share the App

MichaelG.
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Edit: Just off to grab that code

Hi Michael,

I actually wrote a different app for the taut wire method, I don't think I uploaded it anywhere. It has been a while but I think it made use of the wire not crossing the sensor exactly parallel to the pixel rows to gain excellent sub-pixel resolution and it also took a bisector of the line edges as the line shadow is not gaussian when lit from above by a microscope. This also takes care of the converging or diverging wire edges which you can see under high magnification and are caused by the wire stretching more in the centre of the span than at the edges as it flows.

Unfortunately I wont have access to the machine with the code on for a few weeks. Thanks for the offer of some wire but I don't really need it, I found that black fishing line worked perfectly since the app is tolerant of an imperfect wire as described above.

Edit:
Actually it turns out I did upload the code, fill ya boots!
https://github.com/betzuka/laserleve...uilds/wire.zip

Cheers, Joe