Researching SLS

Write here about construction, ideas, equipment, tips n tricks etc. related to structured light scanning
Post Reply
deadmeat30
Posts: 4
Joined: 21 Mar 2020, 02:39

Researching SLS

Post by deadmeat30 » 21 Mar 2020, 03:12

Hello one and all.

New to the forum, and have arrived here from my searching the internet for information.

Im looking to try some SLS and think the David SLS (now HP) range seems a good option.

I would like to use this to scan in small objects around 30mm tall. I came across an interesting video on youtube about scanning with Macro lenses.

https://www.youtube.com/watch?v=elTeaCWSUA8&t=197s

https://www.growshapes.com/blog/3d-scan ... uman-tooth

Now ive been looking at the options, and im weighting up on whether im better to go with an SLS-2 kit, or the SLS-3 kit (improved camera)? Also is it worth dual camera set up (in either configuration).

Lastly, the lenses listed on the article i cant find anywhere. Does anyone know of a suitable alternative to them? Have any users had much sucess scanning smaller items?

Many thanks in advance!

User avatar
OBNRacerMan
Posts: 146
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Researching SLS

Post by OBNRacerMan » 21 Mar 2020, 09:46

I use a 6.3MP camera, and it with a regular 12mm lens allows me to shoot fairly small objects due to its resolution (in fact, I can get the same result with a 2MP camera, bringing it closer to the object so that it occupies the entire frame on it).
test_15_01.jpg
General view before scanning
test_15_05.jpg
On the right you can see how much coin occupied the frame.
test_15_02.jpg
Result
For my current setup, 16mm lenses would be more acceptable
P.S. I did not use a matting spray, because I do not have it, and dry shampoo has a too “grainy” structure, and removes small details on small objects.

deadmeat30
Posts: 4
Joined: 21 Mar 2020, 02:39

Re: Researching SLS

Post by deadmeat30 » 09 Apr 2020, 00:04

How far away do you have the camera to the object?

Do you use extention tubes to get the focal distance closer?

User avatar
OBNRacerMan
Posts: 146
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Researching SLS

Post by OBNRacerMan » 09 Apr 2020, 14:30

deadmeat30 wrote:
09 Apr 2020, 00:04
How far away do you have the camera to the object?
Do you use extention tubes to get the focal distance closer?
I do not use additional tools when scanning. My projector initially allows you to focus from a distance of 100-110mm. The distance to the scan objects in this case is about 200-250mm.
20200308142053s.jpg
Approximately such a setting for scanning a coin
I also scanned semi-precious ornamental stones (for one of my orders), after covering them with dry shampoo, which I use as a matting spray.
20200321145709s.jpg
Original stone
test_19_01.jpg
Scanned stone
P.S. Decreasing the resolution allows you to scan much faster than if you do it in full resolution (also the frequency of the camera with a resolution of 1920 * 1080 is 120fps, and at 6.3MP only 60fps)

deadmeat30
Posts: 4
Joined: 21 Mar 2020, 02:39

Re: Researching SLS

Post by deadmeat30 » 14 Apr 2020, 23:53

Ok, i have a got hold of a computar Macro lens. Now to get the item full frame, i need to be about 40cm from the piece. Which then means that the projector is projecting a lot bigger. So questions come to mind.

1. Is the pixel size of the projector important to the scanning in data?

2. If so, can the projector be ahead of camera? like an extention bracket to bring it closer to the peice? and making the projected area smaller and the pixel size smaller too?

User avatar
OBNRacerMan
Posts: 146
Joined: 12 Aug 2019, 09:46
Location: Obninsk, Russia

Re: Researching SLS

Post by OBNRacerMan » 15 Apr 2020, 08:14

You can push the projector forward (if it does not interfere with the camera and fall into its field of view). But it is better to choose a lens with the necessary focal length for your scanner components. In addition, it should be borne in mind that not all projector models can focus at close range.

In terms of pixel size - the larger they are - the theoretically less noisy picture we get from the camera. But here a lot depends on the manufacturer of the matrix (for me, the marines from Sony remain the best so far).

Also - the higher the resolution of the camera, the more information the program and the computer will have to process, and the greater the “weight” of the scan.

deadmeat30
Posts: 4
Joined: 21 Mar 2020, 02:39

Re: Researching SLS

Post by deadmeat30 » 15 Apr 2020, 09:03

Thanks for the information.

Im currently using the HP SLS 3 kit. Ill get some pictures of what the setup looks like.

Post Reply