Color model with Laser scan intensity values

Development Asset Creation
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1

Hello everyone,

I am currently running some tests to better know RC’s capabilities regarding laser and images merging.

I generated a model from a few _uncolored_ scans. Current coloring settings get me a fully green model, meaning no coloring info was found. I would like to know if there’s any way to use the intensity greyscale channel to use for coloring ?

Thanks !

2

Greetings  

Not for coloring but it is possible to texture it this way. Please navigate to “color and texture settings” in the reconstruction tab and set “texturing style” to any of minimal, maximal or average intensity. 

3

Bump on this one. In my case, my laser scans have both RGB and Intensity data, and I want to bake both to (separate) textures. As far as I can tell, Erik’s suggestion just gets me the maximum of the RGB values. I can’t find a way, inside RealityCapture, to explicitly bake just the laser intensity to texture. I can’t pick the layer - it’s not in the “texturing image layer” dropdown. 

4

Hi sreutersward,

as Erik mentioned, you can use the intensity values for creating texture, if you select this option in the Color & Texture settings/Texturing style

Average intensity:

Visibility based:

When you have scan in 2D view and push TAB, does it change to Intensity? What were your laser scan import settings?

5

Hi Ondrej! Thank you for your quick reply. I made an earlier reply, but realized I had gotten things confused. I think the result I’m getting, and the ones you are exemplifying, is still just a grayscale version of the RGB brightness (plus some black artifacts).  

I use Autodesk ReCap to convert my Faro .fls scans to .e57, which I then import to RealityCapture. (With settings Draft registration, not Georeferenced, Features source = color (but also tried intensity), Noise profile = Noise free). And when I tab in 2D view I do indeed see a colour gradient from dark red, to mid green, to deep blues representing, I take it, high intensity values.

I then tried as above, to simply switch the Texturing style to Average (also Max and Min) intensity. But I’m pretty sure it’s still using the RGB color information, not the actual Intensity layer. I attach some images that hopefully show the results - first the “regular” RGB bake, then the result from Average + the Intensity 2D view.

(In case the image attachments don’t work - I don’t get a preview - here are two links:  average rgb 

6

Hi sreutersward, 

how it looks, when you import the laser scan as Intensity for Feature souce? In this case there shouldn’t be imported colors, just intensities.

7

Hello again! Apologies for not responding sooner, another project caught my attention.

I can’t tell any difference inside RealityCapture whether I choose Intensity for Feature source on import, it seems to behave the same either way. I can still, with either option, see the Intensity in the 2D view as a layer, along with Geometry (which displays the RGB color). But I can’t select the Intensity layer as an Input Layer for baking textures, nor does the Average/Max/etc Intensity options for Texturing Style seem to select the Intensity layer - it appears, to me, to just operate on the RGB data.  

Here is a .zip with a couple of screenshots: google drive link. I’ll insert the images below, too, the link is for backup.

My workflow:

  1. Import .fls scan to ReCap
  2. Export to .e57
  3. (Import to CloudCompare to verify RGB and Intensity works as intended. Intensity is displayed grayscale in CloudCompare, unlike ReCap and RealityCapture.)
  4. Import to RealityCapture with Intensity as Feature source (but also tried with Color and can’t tell any difference in later steps)
  5. Verify Intensity is displayed in 2D view as option to the Geometry (or RGB) layer
  6. Align, build mesh, Texture with default settings.
  7. Then go to Texture settings and select Texturing style = Average intensity. Result appears to just be a grayscale version of the previous, RGB, result.   

If anyone’s curious, here’s the 500 mb .e57: link

I looked at converting the scan to some other file format but couldn’t find one that ReCap or CloudCompare exported that RealityCapture supports importing. Except .ply from CloudCompare, but I ran into a “missing cameras” error on import into RealityCapture and didn’t investigate further.

 

 

8

Hi,

I looked on your E57 and there is a problem with the intensity values. In your case there are intensities with value around 57000:

For RealityCapture it is needed to have those values in range 0-1.

I tested this using my data and when I imported laser scan as Feature source: Intensity, I saw this in 2D view:

In your case it looks exactly as RGB.

When I used this for texturing, the results looked like this (I used Visibility based):

Can you verify the intensity values in ReCap?

9

Hi!

I just wanted to check in to let Ondrej (and anyone else who might be interested) know that I haven’t had chance yet to check on this. As it looks, our workflow in the project will anyways go towards 100% photo-based scanning, so the lidar side of things is getting put on hold. 

But it certainly looks like the data I’m getting from Faro’s .fls -> ReCap -> .e57 -> RealityCapture is somehow faulty. Perhaps I can use ReCap or CloudCompare or something like it to compress the Intensity values to 0-1 range, and that would be read in by RealityCapture? 

On a semi-unrelated note, we are also purchasing a new scanner: our Faro is 10-15 years old. So perhaps the new Leica will be more RealityCapture-compatible, too. 

So I will get back to you if it continues to be a problem. But, as said, for my purposes for now - photo-based scanning is the way we’re going forward. (And not because of this Intensity-related issue)

10

Hi, thank you for informing us.

I think this change can be done in ReCap using some export settings.