Camera and projector fine adjustments

Hi, I'm new here on the forum, and the to the Einscan-S. I've used a laser scanner in the past, but the Einscan is my latest purchase.

I have no problems scanning with it, however, I'm trying to see if there are some fine adjustments that can be done, to increase the apparent resolution of the scans. Currently most of my scans are of relatively small action figures, statuettes and so on. The problem I'm having is that the resulting scans have "soft" edges. Surface features with sharp edges end up with soft rounded edges and corners, and fine features such as grooves (such as gaps between panels) are almost invisible or are very undefined.

I wanted to see if this is an issue with the cameras and the projector, so I did the standard setup as defined by the place mat that came with the scanner, or about 17" from the face of the camera to the center of the turntable. I then placed a vertical piece of white cardboard, and projected an image with some text. I found that the image was not in perfect focus at the center of the table, but it was actually in focus at about 16.25". I then placed a paper with fine writing at that distance, and enabled free scanning so I can see the camera outputs. The writing was blurry, and I had to move everything to nearly 15" away from the right camera to be in focus. The left camera is in focus at about 14.5".

So now to the burning questions:
Shouldn't the cameras be focused on the same plane as the projector?
Shouldn't both cameras be focused equally (goes hand in hand with the question above)
Can they be refocused along with the projector.
Is the distance originally imposed by the place mat (17") "fixed"? By this I mean, does the distance from the camera to the subject figure into the calculations that define the size of the object?

Thanks for your help

Nobody?

Doesn't anyone else have similar issues ?

Dudemeister,

I am fairly new to this myself. I would say that in turn table mode the cameras have been set to an optimum distance for the stated envelope of the scanner so unless the cameras use autofocus in this mode then some part of you object will be out of focus when scanning. In free scan mode you are free to use the cross hairs to judge the focus of the object (or the feature that I posted about recently) to scan.

Have you compared quality of scans from both modes?

I would fire this question to shining3d support directly.

Here is a comparison photo: From left to right, the original model, the turntable mode, and the free scan mode. As you can see, the model has very sharply defined edges, which get a lot softer on the scan. some of the fine detail like thing grooves are almost gone in the turntable auto-scan mode. The free scan is only slightly sharper, but not what it could be.

I think one of the reasons for the lack of sharpness is the fact that the 2 cameras are not focused the same. compounded with the fact that the projector is not focused on the same plane as the cameras, you end up with a "soft" edge, and "blurred" detail.

https://s32.postimg.org/8e57z1yvl/soft_scans.jpg

Do a search in this forum for "focus" I seem to remember a couple of other members with the same issue. Perhaps they can respond.

I'm not seeing too much wrong with those scans, to be honest.
Maybe you're just expecting a bit too much from the Eiscan-s ??
What size is the original model ? That might help us judge you results better.

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Originally Posted by pma

Do a search in this forum for "focus" I seem to remember a couple of other members with the same issue. Perhaps they can respond.

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This one .... http://3dprintboard.com/showthread.p...ighlight=Focus

I did that but unfortunately, there was no real answer. In fact someone else had a very similar issue as mine (the 2 cameras are not focusing on the same plane), was told that this is common and that free scan would take care of it, but it doesn't really help a lot.

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Originally Posted by scobo

This one .... http://3dprintboard.com/showthread.p...ighlight=Focus

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Seen that one, and it looks like he adjusted the projector a bit, which is what I might try this weekend.

BTW, are you the same scobo that is active on Soliforum? I'm on that forum under my last proper name, pirvan.

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Originally Posted by Dudemeister

Seen that one, and it looks like he adjusted the projector a bit, which is what I might try this weekend.

BTW, are you the same scobo that is active on Soliforum? I'm on that forum under my last proper name, pirvan.

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Yeah, that's me. Same usename on the Voltivo forum too.
Small world, eh ? :D

Small world indeed.

To answer your earlier question, the scans are good, don't get me wrong, but I would like to see sharper edges, and better detail on single line grooves and such. The model is 4" tall, and if you look at the photo of the actual figure, you can see how sharp the edges are. The scan has rounded off edges, and the thin grooved lines are no well defined.

Taking into account of the correspondence between the projection resolution and camera resolution, in order to avoid the projection of the grid scan data fringe phenomenon, the camera's focus is not together. Also is the manual focus, between the camera focal plane will have a certain deviation, but the depth of field of the camera enough, does not affect to the scan.

Getting sharp edges is something even the $100.000,- scanners still have trouble with, that's why there is some very expensive post processing software available to get the scan to it's original sharpness and shape.
you still have to do a lot of manual work.

The only way you can get sharper edges is scanning large size and shrinking to a smaller size.

You could also try Blender, I've seen some tutorials on how to sharpen edges with meshes, but you would need to redraw a lot.
https://www.youtube.com/watch?v=IKABoq5sIEM

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Originally Posted by Alfred_technical_support

Taking into account of the correspondence between the projection resolution and camera resolution, in order to avoid the projection of the grid scan data fringe phenomenon, the camera's focus is not together. Also is the manual focus, between the camera focal plane will have a certain deviation, but the depth of field of the camera enough, does not affect to the scan.

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This past weekend I did a little bit of work on the scanner, and found that I can easily refocus the projector.

So for this purpose, I first used a camera app to set the focus location for the cameras, and had them focus on a medicine bottle with small writing on it. The left camera was in focus at about 14.5", whereas the right camera was in focus at about 15". Both cameras appear to have <1" depth of field.

I then place a white piece of cardboard at 14.75" distance to the projector and projected a test pattern. The front of the projector lens has 2 tiny holes which can be used to adjust the focus, so I was able to adjust it for a (near) perfect focus.

Once adjusted, I ran a calibration test, and did a few scan. My scans a visibly sharper, although still not what I envisioned. Using manual scanning is better and you can see that individual scans are sharper, but the auto aligning process ultimately softens up the final mesh, probably a byproduct of some fudge factor and guesswork needed to align and generate the watertight mesh.

On a side note I found the INI file which governs the projected patterns and I'd like to know more about it, and how to modify the values. can we get an idea of what's what?

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Originally Posted by Dudemeister

Using manual scanning is better and you can see that individual scans are sharper, but the auto aligning process ultimately softens up the final mesh, probably a byproduct of some fudge factor and guesswork needed to align and generate the watertight mesh.

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Don't forget you can save the point cloud data in free scan mode then use other software to create a final mesh.

Quote:

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Originally Posted by This

Getting sharp edges is something even the $100.000,- scanners still have trouble with, that's why there is some very expensive post processing software available to get the scan to it's original sharpness and shape.
you still have to do a lot of manual work.

The only way you can get sharper edges is scanning large size and shrinking to a smaller size.

You could also try Blender, I've seen some tutorials on how to sharpen edges with meshes, but you would need to redraw a lot.
https://www.youtube.com/watch?v=IKABoq5sIEM

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I've used Meshmixer to great effect to enhance and clean up scans, so I know how to do it, it's just that I was hoping to cut down some of that work.

The only way you can get sharper edges is scanning large size and shrinking to a smaller size.

Actually that doesn't really sharpen anything, all it does is make the edges "appear" sharper because the model (and the triangles) are smaller. If you need sharp edges you need to remesh the area. There's no substitute.

There is a filter in MeshLab that can globally sharpen a mesh by enhancing peaks and valleys, but it invariably makes the surface coarse. There's also an option in MeshMixer that's designed for smoothing, but you can input negative numbers and it becomes a "sharpening" tool, but it too leaves a lot to be desired.

So usually that leaves me with a lot of manual work.

it would be nice if adjustments could be made to scan smaller detail objects :)
maybe you can get more info on the pattern on the David forums ?

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Originally Posted by scobo

Don't forget you can save the point cloud data in free scan mode then use other software to create a final mesh.

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I've tried that, and I used the Poisson reconstruction filter in Meshlab. Some parts look fine, and in some instances more detailed, but the algorithm used by Einscan is much better at filling in areas with missing data.

So after dedicating almost a whole weekend running various tests and making adjustments, I've pretty much come to the conclusion that the Einscan software is very good at what it does, but it has problems resolving small details, in fact the smaller the scanned object is, the worse the output, but the larger it is, the better the output gets. Probably because it has much more defined (and simply many more) reference points for it's alignment and mesh reconstruction interpolations.

One thing left to explore is the INI file. I don't have it in front of me at the moment, but when I get home tonight, I'll start fooling around with it. From the early look I saw that there are up to 7 steps it can use to project the pattern, but depending on the scan mode or lighting setup, it can use as little as 4 stage. Also there are values describing the pattern (width of each bar, edge blur, etc).

I need to dive into it a bit to see what it does.

maybe you can get more info on the pattern on the David forums ?

I'm not sure the patterns used by the David scanner would be of any use here. David relies on a single camera, and their patterns have both vertical and horizontal lines so the camera can see the deformation in 2 planes. The Einscan uses a pair of cameras producing a stereo image, so it only needs to see the vertical deformation.

Maybe I just got lucky but I've actually been really impressed with the amount of detail it picks out with models as small as 50mm in height.
I've used the David software too and didn't see any higher quality with that although admittedly I only used a cheap webcam.
David is way more configurable and you can use professional grade DSLR cameras with it if you want really high quality.
Personally, I prefer the simplicity and ease of use of the Einscan.

As I mentioned earlier, I started fooling around with some of the settings in the INI. In the Capture Settings.ini, you can change the width of the pattern lines. Here I changed the pixel width in Step 0, from 16pixels to 8 pixels.

[Step0]
pixelWidth=8
frangeNum=100.000000000000
moveNum=12
stepMSecond=40
jumpMSecond=40
[Step1]
pixelWidth=48
frangeNum=94.750000000000
moveNum=5
stepMSecond=40
jumpMSecond=40

Once the ini is saved, the program needs to be restarted for the new settings to take effect. Below are a couple of shots take of the projected image as it looks during a scan.

https://s9.postimg.org/k7fjjh34v/pattern_comparison.jpg

Unfortunately, there is a big problem with this, the narrower pattern affects the apps ability to mesh accurately (Chek out what happened to the arms). Additionally, the resulting scan doesn't appear that much more detailed, so I think I'll stick with the defaults.

https://s10.postimg.org/9uyj428xl/scan_comparison.jpg

So the improvement I'm getting from the focus adjustment will have to suffice... for now.

no idea what you expect - but those scans are bloody amazing !

I've never encountered a similar problem like yours.

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Originally Posted by alimama95

I've never encountered a similar problem like yours.

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Are you saying your cameras and your projector are in perfect focus?

I'd love to see some scan samples, they should be impressive.