Export confidence as intensity (or user value) in LAS/LAZ?

[andyroo]

I just read this question, and was going to reply saying I wish Metashape could export confidence too (I guess it can in PLY format) but I would love to be able to export confidence as intensity or as a user value in las/laz files.

I love the "confidence" addition though, thank you!

[Alexey Pasumansky]

Hello andyroo,

Have you checked the latest 1.6.3 version update? It should support confidence export in LAZ/LAS formats.

[andyroo]

Just came here to comment that I saw it was added in 1.6.3 pre-release! Thanks!

[Joe Adams]

Andyroo / Alexey:

Sorry for my ignorance ... can you clarify where / how the Confidence values are stored in the exported LAS file?

Is it Intensity?

If yes, can you describe how the Intensity values are calculated? These values don't related at all to the scale legend I see in Metashape.

Attached are two JPG screen shots of Metashape displaying Dense Cloud Confidence and Global Mapper displaying Intensity. It looks close but not close enough for me to understand.

Thank you,

Joe

[nola]

I would also like to know where the point confidence is stored in a las file

[Alexey Pasumansky]

Confidence is exported to LAS/LAZ formats via the extra bytes concept introduced in the LAS 1.4 specification.

[dpitman]

Confidence is exported to LAS/LAZ formats via the extra bytes concept introduced in the LAS 1.4 specification.

Hi Alexey,

What is "confidence" and how is it interpreted, or supposed to be interpreted by other applications?  Visually, in MS, it just looks like what other developers call an overlap report.  Using a heat-map to represent where there are a sufficient number of images that "see" each pixel to provide a "good" mathematical reconstruction. 

But with this discussion of "confidence" being exported for use in other applications, maybe "confidence" is something more?

Thank you,

Dave

[Alexey Pasumansky]

Hello Dave,

For the dense point cloud the confidence value means how many depth maps have been used to generate the given point.