Photo Realistic 3D scan

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CanadaRunner
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Photo Realistic 3D scan

Post by CanadaRunner »

hi,

I'm looking for a way to create photo-realistic scenes (mainly indoor but also looking for outdoor) based on point clouds by using a TLS and a camera system. The end goal is to visualize it in an gaming engine as unreal engine. I don't have a prefered product (point cloud or mesh) as in the upcoming version of UE5 and already the actual version both type of data is supported. It should be possible to use different lighting to set different moods (sunset, daylight, etc.)

As of now, I would go for two separate systems as the camera inbuild into laser scanners aren't as of high quality as even some "cheaper" DSLR/System cameras. Therefore I would scene first the scene with a TLS (X330, RTC360, BLK you name it) and then would swap it for a panoramic camera system for capturing the data.
During my (still ongoing) research, I found several requirements to achieve my goal:
  • HDR image capture sequence
  • precise panoramic system to meet the nodal point and have a precise alignment
  • precise alignment of camera center to TLS center -> at best mechanically
  • full 3D dome scans
But there are still some open questions:
  • How to capture a color-accurate HDR image
    -> do it need a color checkerboard for that
  • Should the scene have meshed before the coloring or should the coloring be based on the point cloud and then meshed
  • How to deal with partially shadowed/lighted scenes
  • Should active lighting be used (flash or lamps)
  • Deshadowing the images to get shadow-free scenes 
  • Should I go for another approach, e.g. taking TLS scans just for the overview and detailed assets by photogrammetry and merge them later?
The question is now if you are aware of any workflow, pipelines to achieve my ambitious goals! Libraries, Software, Tutorials everything is welcome!

Thank you very much for any suggestion! If there is any clarification needed - please let me know!
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steves01x
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Re: Photo Realistic 3D scan

Post by steves01x »

For external DSLR set ups for scanners such as P40 check out LizardQ and Nodal Ninja.
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Re: Photo Realistic 3D scan

Post by Leandre Robitaille »

Look at my reply in this thread
viewtopic.php?f=46&t=16628
Edit: as for poorly lighted scenes just wrap the main pole of your tripod with strong led light strips ;)
With a faro scanner just use hdr with horizontal weight.
You could also consider bringing a few spotlights if needed. Obviously color reproduction won't be 1:1 but it will look good.
Last edited by Leandre Robitaille on Wed Jan 27, 2021 1:29 pm, edited 2 times in total.
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Re: Photo Realistic 3D scan

Post by btylutki »

Here is what comes first to my mind.

How to capture a color-accurate HDR image - Lock Aperture-find hyperfocal distance, Lock WB, Shot RAW as many stops as needed for the scene.
-> do it need a color checkerboard for that - 18% gray card for White Balance compensation later during post processing in RAW.


How to deal with partially shadowed/lighted scenes - HDR photography with appropriate dynamic range cover should take care of that.

Should active lighting be used (flash or lamps) - you can compensate exposures with flash but pay attention to available artificial lighting. For example: sodium bulbs vs flash temp. You can use color filters with flash to compensate for this. Use some sort of diffuser to match wide angle.

Also, every lens has distortion. Distorted photo will be mapped to accurate point cloud.
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Re: Photo Realistic 3D scan

Post by steves01x »

Is it a photo realistic 360 scan/photo or are you wanting a separate scan data set to combine with a photogrammetry job?

Check out Reality Capture - https://www.capturingreality.com/
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Re: Photo Realistic 3D scan

Post by sim.herrod »

We use a Faro S150 with HDR imagery processed in Leica Cyclone for the laser scanning part, a Canon DSLR or UAV with ND filter edited in Lightroom for the photos and Capturing Reality to combine the two.

Scans use checkerboard targets shot in with a Total Station, photos use an X-Rite ColorChecker Passport for colour editing. For lighting when needed, we use LED strips behind a diffuser on the shaft of the tripod.

The non geo-referenced photo components can be moved to the geo-referenced scan data components within Capturing Reality.

We have also tried Agisoft Metashape, but prefer Capturing Reality.
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Mike Annear
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Re: Photo Realistic 3D scan

Post by Mike Annear »

I remember seeing really nice results from the Z+F IMAGER 5016 with inbuilt LED lighting and HDR imagery.
I haven't seen any results lately, does anyone have any recent experience with this scanner ?
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Re: Photo Realistic 3D scan

Post by AnthonyM »

Hi,
I recently read the post below from a guy who specialises in 3D laser scanning for Hollywood movies, including how they incorporate high megapixel photography. They do go into some detail regarding their equipment and the various software that they use; worth a look.

https://beforesandafters.com/2020/07/06 ... ick-3/amp/
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Re: Photo Realistic 3D scan

Post by CanadaRunner »

Thank you all for the interesting inputs.

I see that most of you would go for a photogrammetry approach. Laser scanning just came to my mind as its faster and still get very accurate models.
I see the point with PG that the respective color information is much more accurate and at least for coloring the LS I would add photos, as these inbuild cameras are just trash. I was quite disappointed by the quality of the P50, RTC360 is okay. Z+F the image is also okay, but asp. in scene with huge lighting differents it's also no good. But as I think this should be anyway avoided.

I will investigate now in all your directions and will come back when I found a suitable workflow

But always in for new ideas!
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Re: Photo Realistic 3D scan

Post by Peyman Bashiri »

Hello Mike,

I have uploaded this video a couple years ago about Z+F5016 LED light and imaging.
https://www.youtube.com/watch?v=sbCJjbrDWFs&t=14s
Peyman
PS, sorry about the tripod

Mike Annear wrote: Wed Jan 27, 2021 11:29 pm I remember seeing really nice results from the Z+F IMAGER 5016 with inbuilt LED lighting and HDR imagery.
I haven't seen any results lately, does anyone have any recent experience with this scanner ?
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