3D scanning - high resolution for small objects

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barryvanbakel
Posts: 10
Joined: 02 Jan 2021, 14:58

3D scanning - high resolution for small objects

Post by barryvanbakel »

Hi,

I'm interested in 3D scanning since a while and only experimented with photogrammetry.
Now I need the resolution as high as possible and am very impressed by the 'macro scanner' or https://www.mechscan.co.uk/macro-3d-scanner/

My aim is to 3D-scan small fossils, size of a small coin. Actually it doesnt need to be 360 degrees most of the time.

Anybody built such a macro 3D-scanner?
ANy ideas on how to build such a thing?

Thanks in advance,
Barry
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OBNRacerMan
Posts: 287
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: 3D scanning - high resolution for small objects

Post by OBNRacerMan »

Hey. I am doing macro scanning.
Since I do not yet have the opportunity to greatly modify my projectors (with the replacement of the lens, as it is done by the your link to Macro 3D Scanner ), I use one of them exactly as suitable for such a task without alterations. As a result, I get a small projection field, where even an HD projector allows you to create a sufficiently high pixel density per 1 sq. centimeter of projection.
While this is a simplified solution, it does what I want (though not as well as expensive professional solutions).
Toy soldier 60mm high
Toy soldier 60mm high
Toy soldier 60mm high
Toy soldier 60mm high
Jewel
Jewel
Coin
Coin
Coin and projection size
Coin and projection size
Soft: RangeVision DIY, Calibration panel/Rotary tables - RangeVision, Prj: Byintek UFO R9, Cam: Daheng Mercury MER-630-60U3M-L (USB3.0, monochrome) x2, Obj: ZLKC HM1628MP10 (F2.8, 10Mp, 16mm) x2 & Azure 3518M3M (F1.8, 3Mp, 35mm).
barryvanbakel
Posts: 10
Joined: 02 Jan 2021, 14:58

Re: 3D scanning - high resolution for small objects

Post by barryvanbakel »

Hi, many thanks for your reply!
Great to see your results. Looking at the ring and coin, I would say that is about the resolution I need.

Forgive me for my very little knowledge on the scanning technique,....I have some questions.
Does the type of projector matter for such macro application?
Why would a replacement lens be better than a fixed lens, like your setup? Does that determine the pixel density?
And is the camera/lens also important?

Thanks in advance,
Barry
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OBNRacerMan
Posts: 287
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: 3D scanning - high resolution for small objects

Post by OBNRacerMan »

Household projectors are designed for viewing movies, so their optics are initially focused on the large size of the resulting projection from a relatively short distance.
Requirements for scanning are different. There, the best option is obtained when the projection area is as close as possible in size to the scanned object - this provides both the best brightness (almost nothing of the light flux leaves the object) and the density of the projected pixels of the projector matrix on the object. Also, cameras should be able to "see" the object so that it fills the frame as fully as possible.
In the presence of high-resolution cameras (for example, like mine - 6.3MP), they perfectly see these pixels from the projection even from a small distance (0.3-0.4m) and the surface of the object turns out to be too "noisy" (and in this "noise" small details are lost ).
Therefore (with macro) you usually have to move the projector as close to the subject as possible. And having an interchangeable lens would greatly simplify this and expand the scope of the scanner.

Here, for example, how cameras see an object from a distance of 35-40cm with a lens of 16mm (left) and 35mm - on the right. And pay attention to the thickness of the projected crosshairs from that distance.
left - 16mm, right - 35mm
left - 16mm, right - 35mm
And here both lenses are 16mm, and the distance to the object is about 120-150mm - it is clearly seen that the centering "cross" has also "lost weight" (that is, there are more pixels on the object)
both 16mm
both 16mm
Soft: RangeVision DIY, Calibration panel/Rotary tables - RangeVision, Prj: Byintek UFO R9, Cam: Daheng Mercury MER-630-60U3M-L (USB3.0, monochrome) x2, Obj: ZLKC HM1628MP10 (F2.8, 10Mp, 16mm) x2 & Azure 3518M3M (F1.8, 3Mp, 35mm).
barryvanbakel
Posts: 10
Joined: 02 Jan 2021, 14:58

Re: 3D scanning - high resolution for small objects

Post by barryvanbakel »

Clear explanation and example, thx.
So the projected area needs to be as small, and as sharp, as possible, I understand.
Which projector do you now use for macro scanning? And which projector would be ideal for macro work; a pico scanner?

Camera: I do a lot of macro photography and have quite a few lenses to get small subjects frame filling. I think that a DSLR with electronic shutter like a Canon 50D is sufficient too?

Kind regards,
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OBNRacerMan
Posts: 287
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: 3D scanning - high resolution for small objects

Post by OBNRacerMan »

My main projector - in the signature - is a small, not very bright Byintek R9 (old model, no longer available). But he knows how to focus better than anyone else from the smallest distance.
In general, the LG PF1500 projector (or its slightly more modern version of the LG HF60) is considered optimal for scanning - both of them are not produced, so you can only find a used version, if you're lucky - it will not be too "tortured" with operating time 1- 5 thousand. hours.
But for the macro, you still have to redo it.

Regarding cameras and lenses - I don't know how and in what software you want to use your DSLR. From the very first version of the scanner, I used industrial video cameras (and only with the very, very first - a webcam - from which it is difficult to expect a decent result, even if you change the lens for it).
Му current setup
Му current setup
Soft: RangeVision DIY, Calibration panel/Rotary tables - RangeVision, Prj: Byintek UFO R9, Cam: Daheng Mercury MER-630-60U3M-L (USB3.0, monochrome) x2, Obj: ZLKC HM1628MP10 (F2.8, 10Mp, 16mm) x2 & Azure 3518M3M (F1.8, 3Mp, 35mm).
barryvanbakel
Posts: 10
Joined: 02 Jan 2021, 14:58

Re: 3D scanning - high resolution for small objects

Post by barryvanbakel »

Thanks - it looks as a clean, simple setup and with great result on macro.
What modifications needs to be made to the LG projectors to scan macro?

If you ever consider changing your gear, drop me a line. I think it is too difficult for me to build a structured light setup.

Kind regards,
Barry
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Micr0
Posts: 514
Joined: 15 Nov 2016, 15:20
Location: New York City

Re: 3D scanning - high resolution for small objects

Post by Micr0 »

barryvanbakel wrote: 05 Jan 2021, 18:27 Thanks - it looks as a clean, simple setup and with great result on macro.
What modifications needs to be made to the LG projectors to scan macro?

If you ever consider changing your gear, drop me a line. I think it is too difficult for me to build a structured light setup.

Kind regards,
Barry
Have a look at portable presentation projectors like the AAXA P5 and P7 (larger but 1080p). They can produce focused images that are smaller than home theater projectors. I have a P& and it can produce an image in focus that is ~80-100mm diagonal.
µ
barryvanbakel
Posts: 10
Joined: 02 Jan 2021, 14:58

Re: 3D scanning - high resolution for small objects

Post by barryvanbakel »

Thanks for your answer too, micro!
AAXA P5 and P7 look great to me. Available, quite affordable, and the smaller projection area is excellent for my small objects.
Is there a particular software which is better in macro than another? With which software do you scan?
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Micr0
Posts: 514
Joined: 15 Nov 2016, 15:20
Location: New York City

Re: 3D scanning - high resolution for small objects

Post by Micr0 »

barryvanbakel wrote: 06 Jan 2021, 15:06 Thanks for your answer too, micro!
AAXA P5 and P7 look great to me. Available, quite affordable, and the smaller projection area is excellent for my small objects.
Is there a particular software which is better in macro than another? With which software do you scan?

HP 3D Scan (David Laserscanner) v5
µ
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