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Author Topic: Export multiband ( >3 bands) point cloud to LAS 1.4 and COPC with "extra bytes"  (Read 4800 times)

andyroo

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Metashape uses "extra bytes" fields to export xyz normals and confidence to LAS files. I would like to request that for dense clouds with more than 3 bands, additional bands can exported as "extra byte" fields with a user (or band)-defined field name.

We are generating point clouds with >3 bands (6+ uint8 bands) and would like to be able to carry bands besides RGB as extra bytes (preferably with band names) into LAS/LAZ/COPC format without going through an intermediate conversion step using XYZ or PLY formats. As far as I can tell, metashape currently only exports 3 bands to LAZ (or possibly a master band if set differently).

andyroo

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Since v. 2.2.0 is in the pipeline I figured I'd re-request this feature - It would be nice to export additional bands as "extra bytes" fields in .laz and copc from the (dense) point cloud. right now it looks like I can only export this to PLY, and I need to rename the scalar variables from "color, color, color" to "band4, band5, band6" (or whatever I name the bands in metashape) in the PLY header. If I try to export to txt, only band4 and band5 are properly exported, and band6 for some reason has very low values (like 0-4 or something).

 - to clarify - we are generating dense clouds with a master-slave camera setup as described in the multiband guidelines, and each camera having 3 bands of 0-255 uint, for a total of 6 bands mapped to the dense cloud. If I set camera 1 band index to 0 and name the channels Red, Green Blue, and camera 2 band index is 1 and cameras are named Red, Green, Blue, then Camera 2 values are in the RGB channels. If I name camera 2 bands band4, band5, band6, then I can't export them in laz, only PLY, and they are exported as "color color color" fields in the header. As far as I know there's no other way to export all 6 bands.

Then I guess I need to develop a PDAL recipe to convert the PLY to LAZ with the color fields mapped to extra bytes, but probably have to rename them first since they're identical.