Video Camera as a tool

[dvanr]

Continued from here (http://www.talkshopbot.com/forum/messages/27/12746.html?1145325852#POST34948)

Bill,

Another interesting link , with pattern recognition.

http://www.seattlerobotics.com/index.htm


Gerald,
Make sure that the laser light is parallel to the z-axis for your method to work. The camera alignment method I described would get the laser light parallel. Your method is very similar to the method used to do optical alignments on photoplotters.

David,
Good point. I can't get rid of both offsets. I have moved the camera in line with the routers x-axis, that gets rid of the y-axis offset.The 4 inch offset in the x direction at the back of the sheet I can live with.

[dvanr]

So far it works pretty good. Very Handy for checking where the bit is going to cut a pre-printed piece of material.



5409

The video screen is about 4 inchs square. In the image above the magnification would be about 2.5X , move camera up another 2 inchs and it changes to 1X.

A cut routine was added to swap the bit and camera position (using the measured offset) without changing the DRO values.


5410

[gerald_d]

Good stuff Dick!

Any comment on keeping the lens clean?

[dvanr]

Gerald

The lens doesn't get as dusty as I expected.

Fair bit of airflow from the router and lens pointed down helps keep the dust to a minimum. Dust does get on the lens but it is not as noticeable as you might expect.

I get more dust stuck to the monitor screen, or in this case between the plastic reticle and the screen.

[gerald_d]

The advantages of the system are very obvious. What do you see as the down side? Or, what do you feel you need to develop further?

[dvanr]

Sensitivity to light levels may be the only downside that I have seen so far. It has auto gain but it can struggle a bit if shadows are thrown by the gantry. I'm hoping a small light will cure the problem.

The leveling stage works really well but still looks too big. It could still be made smaller and more protective of the camera. But for now it stays the way it is.

I'm curious to see how long it all lasts. M.I.C. stickers every where and it shows in the build quality. The camera really had to be tilted to get it aligned, so it looks funny , but it works. If I did it again I would use the same size camera as resolution is more than enough, just better optics quality.

[dvanr]

Here is the routine for the camera, it can be used for offset laser pointers as well. Just change instances of camera to laser and put in your own offset values.

Cheers D



Enter the XY values needed to move the centre of the bit to a marked point centred on a 'camera or camera in inches
&CamOffsetX = -3.792
&CamOffsetY = .129
&Xlimit = 96
&Ylimit = 48
&direction = 0
&SetAnswer = "N"
&newXvalue = 0
&newYvalue = 0

'----------------------------------------------------------------Read the starting speed values to reset later
&start_XYmove_Speed = %(71)
&start_XYjog_Speed = %(76)

&XYapproach_Speed = &start_XYmove_Speed
&XYtempJog_Speed = &start_XYjog_Speed
If &XYapproach_Speed > 2 then &XYapproach_Speed = 2.0
If &XYtempJog_Speed > 6 then &XYtempJog_Speed = 6.0

VS, &XYapproach_Speed,,,,&XYtempJog_Speed '... and assign slower speeds
'---------------------------------------------------------------------------------------------------------------
'Main Program

SK