Camera For Touchoff

thank you i really appreciate it

Actually, auto edge detection with the USB camera does not look too hard. You can look for edges in a video stream in 15 lines of code:
medium.com/@akash555bhiwgade/edge-detect...d-webcam-8f980c79a86

So if you started in the middle of the sheet somewhere, you'd move along the X axis towards 0 until you find an edge. Then centre the camera crosshairs on that edge (you may need to set the mm per pixel to coordinate motion. Save that position. I think the system would allow you to read coordinates along the edge so you could calculate the angle to follow to the home position.

Then move along the Y axis in the direction determined until you find a corner (another 15 lines of code) and you are there. Save position and rotate axes.

Only problem is I don't have a USB camera but I think a proof of concept could be achieved with a couple of photos of the sheet. I might try that.

I think the scope creep on Rod's idea is you end up detecting all edges on used material, so you can thread the needle on nesting tightly ad hoc...shall I go put in a feature request?

phillc54 wrote:

I think it would be quicker to do it the way it is.

I don't like to make assumptions without data. We don't know yet.

Mud wrote:

I think the scope creep on Rod's idea is you end up detecting all edges on used material, so you can thread the needle on nesting tightly ad hoc...shall I go put in a feature request?

The only reason Rod's idea came about is somebody asked me how it could be implemented. We were thinking of sensors of some kind. I was told high end machines offer that feature. I had no idea how it could be done. I also had no idea about opencv either. But when it was discussed here and ended up in linuxcnc, I had a look at what opencv was and what it could do, I thought it might be the enabler to support a feature put on a wish list over 6 months ago.

I did not envisage that the intended use was to recut remnants. I try and cut them off at the end of a run with a sheet sever. But its probably not that much of an issue if the start point was between the left edge and the first void. Its really for those guys cutting 16-25mm sheets that are too heavy to align by moving the sheet. Typically, they don't like to remove the sheet until it is just a skeleton.

Yeah, I'm putting words in your mouth Rod - was just pointing out if a wandering edge detector was implemented, mapping the whole sheet would not appear to be much extra work, and a big feature.

Where can I find the wish list?

Mud wrote:

Yeah, I'm putting words in your mouth Rod - was just pointing out if a wandering edge detector was implemented, mapping the whole sheet would not appear to be much extra work, and a big feature.

Where can I find the wish list?

I get it now. So scan the whole sheet,stitch them together and put an overlay on the screen preview where the voids are! That would be cool.

Phill, I have no idea on the speed as I've not played but I am so glad our borders are locked down to prevent Victorians and their beer from polluting our XXXX Sunshine state. Mater of fact, I scored a free carton of that XXXX stuff yesterday!