Hello, I have just recently received my Metroy Pro (first scanner I have ever used). Finally i have had time to start testing around. All in all it seems like a very good scanner and the software has been very intuitive.
I have been testing the scanner initially on some objects with known dimension to check the accuracy. My first test looked very promising. I have a 65.001mm hole that i measured after scanning (using GOM inspect).
Then i moved on to a 200m long gauge block, and this is where I’m running into some trouble. I have tried to scan the object several times now, using paralell lines, cross lines, marker traking and global markers. But all my measurements in GOM indicate that the part is approximately 199.7 - 199.8mm although it should be very close to 200. Any Idea what i could do to improve this measurement or if I’m doing something fundamentally wrong?
Below are some pictures of the scans and marker setup.
A 0.2 mm lost on so small distance is little too much . But noises can add dimension especially from 3D spray on the surface. As 3D spray is clearly visible in my scans . However I would expect not more than 0.1 mm error to be acceptable
You did not mention what mode you where used , Full Field or Laser mode ?
What was your fusing settings, what was your meshing settings ( GRID) anything of that will influence the final dimensions .
For example if you fuse the point cloud at 0.10 mm make sure the GRID settings under meshing also have the same settings of 0.10 mm so you don’t add additional artificial points as they can add level of noise you don’t need.
Also very important cleaning between fusing and meshing , overlapped points and lose points .
I can see from the side that there the surface is slightly uneven so try to fuse it, clean and mesh according to my tip and see if anything improve .
If not improvement then I would suggest to recalibrate the scanner .
I will test out on my side to see how much difference I get at the same length of an object.
Hey I first tried to do as you suggested, with using the same grid size (used 0.3 throughout all the steps and tests). And i had the same result, approximately 199.7mm.
After that i performed the calibration and used the same settings. Very happy with the result!
But in the future where the accuracy is very important to you , make sure you keep it not lower than 0.15 mm at max while fusing and meshing ( Grid) laser mode
0.3mm is little too low and you may lose some finest details , that’s the reason you got slightly less accuracy but still amazing result regardless!
Usually anything to 0.5 mm is acceptable, depending on the size of the scanned object and its form . How smaller it is , how higher the settings for best results .
The Accuracy is already build in the device , the rest is only good fusing/resolution settings to accomplish the good results .
You say strange things, on such small objects, the accuracy of 0.2 and 0.5 is inexcusable, this is the level of the first-generation kinect. Are you perhaps forgetting one zero? for example 0.02 or 0.05?
perhaps you’re right, the language barrier was to blame, in the first message the translation sounded that at such a short distance the loss of 0.2 mm is not much. although it is written a lot without translation. Next, I agree you wrote about the merger. I’m glad we figured it out. The result after calibrating 0.003mm does not sound likely at all, I would expect this from SLS mode but not laser, however, do not forget that the length measure is spray-coated, so the original size is slightly negative, nevertheless the result is excellent.
The translation was ok , you just missed the context of the whole conversation .
Accuracy is always build into the device , fusing point is a resolution based on the details of the scanned object .
And for the subject of the above conversation the settings was the best to archive the best accuracy without inducing artificial noise that altered the measurements , the result was pleasant, so it worked very well . That’s what matter !
The problem is the automatic translation of the above phrase. otherwise, I’ve been into the subject of scanning for a long time and I understand the difference.
