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Custom lens shading with stereopi

Posted: Mon Jan 25, 2021 12:42 pm
by austinbingham
I've been working on a stereo capture system using a Raspberry Pi compute module and IO board. One aspect of this system is that uses non-standard lenses (i.e. not the V2 camera), so it requires a custom lens shading table. After a fair amount of experimentation and discussion, it appears that custom lens shading tables and stereo capture just don't work (yet); the firmware camera control won't apply the table to both cameras, and CPU control (e.g. with libcamera) doesn't work with multiple cameras.

Is the situation any different with StereoPi? That is, is it possible to apply a custom lens shading table to both cameras? Assuming it's supported, can anyone confirm that they've successfully done it?

Re: Custom lens shading with stereopi

Posted: Mon Jan 25, 2021 12:55 pm
by Realizator
Hello austinbingham,
To start with, we didn't plaid with this option at the StewreoPi. I have a shading fix experience a lot of years ago with ov2643 (and not with Pi, but with TI DM365). As I remember, this table can be written to the sensor itself while initialization.
I don't know how it works at the Pi, but the most detailed dive in this scope I was able to fid is this article from Arducam: https://www.arducam.com/docs/cameras-fo ... libration/

I know that not all options are supported in the stereoscopic mode. As a workaround, you can try to work with each camera independently BUT do external hardware sync (oscillator soldering). So you'll have a couple of, say, raspivid, each working with its camera (-cs 0 and - cs1), but sensors are hardware synced.