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Messages - 3D_Scan_Fan

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61
Hi guys, I dont know how else to explain this but I've been haivng some trouble with Photoscan recently.

After having taking photos of my subject by rotating around him three times resulting in 120 photos from all angles I load them up into Photoscan and in the beginning the alignment of the point cloud was terrible, it was almot like there was two face going on here, I really didnt know what to do.

Then I changed some settings on the Key Points and Tie Points which resulted me in a much more dense but sligtly more accurate result which gave me a point cloud with great alignment, very little overlap, I thought I got the right preferences correct in my settings. Then when I attempted to redo this again I once again got a horrible result which I am now stuck on and cant think of how I managed to get the better one.

The only time I managed to duplicate this result again is when I loaded a new batch of (the same) photos with different colour corrections applied. I saved it as soon as I saw a good result, but when I restarted everything again (without changing any of the settings) I got a bad alignment again.

This is really frustrating as the process of each stage is incredibly time consuming (literally leaving my computer on over many nights!) I dont understand what is going on here, I had it right early on and then it changed.

Can someone help me out here?

62
General / Re: estimate image quality
« on: March 16, 2015, 01:49:56 AM »
Sorry for bringing this up again, but in regards to the Estimate Image Quality, isn't there any way to bypass this?? Because I find it unfair that PhotoScan would reject from the photogrammetric processing.

63
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 12, 2015, 05:17:36 AM »
I see. I'm going to give it a go (with the black shell first). But about hte accuracy, am I on the right track by using those printed coded markers?

Quick question as well, can PhotoScan work with photos that were taken from a rotating turnatable??

64
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 12, 2015, 04:05:54 AM »
A White shell is much better if you are concerned about the accuracy. Paint or a developer spray might add 0.003" or so, and the crevices in your part might force you to apply more coats to get better coverage, resulting in greater thickness in some areas.

Maybe I have misunderstood what you mean by micron accuracy,     1 micron = 0.00003937 inches (0.001mm)

So if you truly need 1 micron accuracy, what machine are using to create this part?

Well then that means I can just go ahead and get a white shell, thus I wouldnt need to do anything like paint of coat it with developer spray then, I am right? :D

... and what 3D printer is going to reproduce that accuracy ;)  Easiest way to explore the limits is to start with your calibration target. That will give you a quick idea of what magnification you're going to need and whether or not it's going to be practical.

Is this calibration target a way for getting accurate measures? or to do with the camera's lens due to distortion? I've printed these coded markers from PhotoScan (they're like these incomplete circle bars with a white dot in the middle), that's the only tutorial I could find about getting and setting up scale bars and measurements.

Have you guys heard of the ProJet x60 Series Professional 3D Printers???  ;)

65
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 10, 2015, 06:13:58 PM »
Well i could always use a white coloured controller shell, would that be better perhaps? :D

I do have a couple of macro lenses that would help for the very small objects, and in terms of the depth of field I could always close-down the aperture and do a capture at a long shutter speed in order to get it exposed. Would this work?

I thought too that the deep crevices might be a problem, but surely if you capture it at many different angles (via. turnable at small increments?) then surely that would provide it enough parallax for it to calculate the difference of depth within them.

And this is not only for this object that I would want scanning, there will be others that will need such precision accuracy, once again how would I go abut achieving micrometer accuracy? How would I calibrate or set it up? for Photoscan? 

66
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 09, 2015, 07:22:08 PM »
Does anyone know if it is possible to achieve micrometer precision accuracy with Photoscan?

One thing to note is there is a difference between accuracy and resolution.

This is true, however the reason I brought up the two factor was that I was thinking of somehow using a micrometer ruler or chart or anything of the like and place it in my shot when I photograph the object, therefore if the resolution was good enough or even if the lens was capable to resolve micrometer distances then I could potentially use those points on the scale/ruler as reference to set up my measurements.

It likely that you do not need such a small value for either one for your application. You should determine the minimum acceptable values for your application. This has an associated cost in time and money and requiring a lower value will increase both.

I can pretty much assure you I do need such a value, as I have previously mentioned I want tot ry and use this method to make a pretty damn accurate representation of my object that will act as a replacement part if it ever gets damaged, I am prepared to do some work on it but I do need to get it down to that level of accuracy.

Would anyone know if this is possible with Photoscan by any chance?

67
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 09, 2015, 04:20:14 PM »
Also i don't understand how a scale bar with two points would help me get very precise measurements, Im looking into micrometer accuracy and i don't think your standard dslr would be able to resolve that detail (i could be wrong).

Does anyone know if it is possible to achieve micrometer precision accuracy with Photoscan?

68
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 09, 2015, 01:25:12 AM »
Well i want the accuracy to be strictly 1:1, literally if I was to scan something and then have it printed it has to be 99-100% identical, how would I go about achieving this with Photoscan?

I understand what you're saying about the complexity of the shape, my main worry is the reverse side where there are many inserts and fittings that could be difficult to capture as you can see here in the attached photo, but i am hoping for the best personally. My idea is to capture each photo with long exposure shots to really get the details within the shadows for it to register during scanning.


69
General / Re: Calibration/Accuracy possible with Photoscan?
« on: March 09, 2015, 12:16:35 AM »
It's around the size of an Xbox controller, and smaller like the buttons and parts inside it.

Would it suffice?

70
General / Calibration/Accuracy possible with Photoscan?
« on: March 08, 2015, 10:03:07 PM »
Hey guys! Im new here, how are you all doing? :D

Im a great fan of 3D scanning and in particularly this piece of software on what it is able to achieve which i think it's pretty amazing especially compared to hardware scanning that cost ten times more than what we have here!

In regards to that im really wanting to do somesort of scanning of some parts through Photoscan but accuracy is priority in this scenario, which is probably why hardware scanners might have that advantage for those who pixel peep. I am after capturing objects with something like 0.5% tolerance or 0.01mm+/- accuracy to really get those fine details.

My question then is, is it possible at all to achieve that kind of accuracy with Photoscan by any chance? Is there any sort of calibration that would need to be done perhaps?

I hope you lot understand what im saying or what i am after. I hope all is well and i look forward hearing back too! :)

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