Bottom Camera Calibration Fails

[Greg Toman]

I am putting together an Opulo and am calibrating it. It places part with poor accuracy. I believe the problem is the bottom camera vision is incorrect. I think it sees the part I am placing, but interprets what it sees with the opposite error than what actually exists. When it then places the part, whatever error it found corrected with the opposite sign, resulting in twice the error that probably existed.

I noticed that under "Nozzle TIps", I select a nozzle and use the "Calibration" tab to calibrate. This is successful. However, when I try "Calibrate Camera Position and Rotation", the bottom camera shows the nozzle moving to different locations, but the "heat map" I have enabled appears on the opposite side of the center as where the nozzle appears. In other words, it appears something is backwards, and the software expects the nozzle to move one direction in the camera view, but it moves the opposite.  Maybe there is a direction or orientation setting somewhere?

I tried the "Advanced Calibration" under the bottom camera settings, and it ran for 15 minutes or so with no complaints that I could see, but after it was done the bottom camera appeared to be digitally zoomed in way to far (there was no longer an image...just lighter or darker for the entire camera view depending on what the camera was seeing.) When I tried to run a job, I got the error saying the viewing area was cropped to zero. 

Any advice would be appreciated! 

Greg

PS. As an experiment, I tried to disable the bottom camera, but it kept being used. I think I will need the extra accuracy the bottom camera will eventually provide.

[Greg Toman]

Important observation!  When performing the "Calibrate Camera Position and Rotation" under the Nozzle Tips settings, the heat map (where I assume the CV is looking) is displayed on the opposite side of the x-axis on the screen from where the nozzle moved. That is,  the vision is looking at the location with the wrong sign on the Y coordinate.

[tonyl...@gmail.com]

First, what version of OpenPnP are you using?

Second, are you following all the recommendations in Issues & Solutions? It is pretty good at walking you through everything you need to do.

Generally, you shouldn't be using "Calibrate Camera Position and Rotation" under the Nozzle Tips settings.

Please post your machine.xml file and your log file (with the logging level set to Trace) after running Advanced Calibration on your bottom camera.  The most common problem with Advanced Calibration on the bottom camera is poor lighting which makes it difficult to detect the nozzle tip in the far reaches of the image.  It helps to crop the image down to a square (on the Advanced Calibration tab, under General Settings, set both the Cropped Width and Cropped Height to the smaller of the camera's resolution, i.e., if your camera's resolution is 1920x1024 pixels, set both the Cropped Width and Cropped Height to 1024) before running Advanced Calibration. For bottom cameras, it also helps to turn-off any overhead lights in the room so that there isn't a lot of glare competing with the nozzle tip.

Tony

[Greg Toman]

I figured it out. There is a "Flip" setting in the bottom camera setup. That fixed it.  Odd how it wasn't obvious that the camera needed to have that checked, as everything appeared ok. I am not sure it appears any different after fixing it, but it works now.

I hope this helps someone else! 

[Greg Toman]

Thanks for the advice. I will do that. I bet the advanced calibration will work now that I have the camera setting corrected.

I had not seen the "Issues and solutions", unless you mean the one inside of OpenPnP, which I looked at a time or two.

Thanks so much for helping! I am getting close. Parts are starting to place, and accuracy is improving. 

[tonyl...@gmail.com]

Advanced Calibration figures out on its own how to flip and/or rotate the images so those settings shouldn't matter.

I highly recommend you work your way through I&S as you may have to repeat things if they are done in the wrong order.