Hi Sophie and Pekka On Tue, Jan 10, 2023 at 10:46:26AM +0200, Pekka Paalanen wrote: > On Sat, 7 Jan 2023 22:58:41 +0100 > Sophie Friedrich <lkml@xxxxxxxxxxxx> wrote: > > > Hello people, > > > > over the past months I've written a driver for the Guide MobIR Air¹ > > USB-C thermal camera. The driver uses v4l2loopback and runs in user > > space with python.² The driver manages camera state, calibration and > > conversion of the raw microbolometer to temperature values. > > > > In my research I couldn't find any mentions of a thermal camera support > > in the Linux kernel nor the media subsystem, so I assume I'm the first > > to ask here and we would presumably need lay out some ground work. > > > > The current camera driver outputs the temperature in the Y16 format as > > Kelvin * 100 (i.e. 28056 (raw) -> 280.56K -> 7.41°C). This allows for > > further processing down the line with i.e. OpenCV, but has its > > limitations. Especially as temps of only up to 382.2°C can be displayed > > currently. > > > > Does it seem feasible to integrate support for thermal cameras in the > > Linux kernel and more specifically in the v4l2 subsystem? > > Hi, > > since no-one else replied to you yet, I thought to mention my 2c > (I don't really do camera stuff myself so far): > > Perhaps the best place is to reach out to the libcamera community: > https://libcamera.org/ > cc-ed the libcamera list I agree it would be interesting to better understand what you mean by driver here. The camera seems to be a UVC camera, does it deliver frames with the current UVC driver or do you need kernel patches to support it ? I would also be interested why it needs to go through v4l2loopback.. > It sounds to me like you want to do some hardware-specific > processing in userspace, and it might not be great to try to come > up with a generic thermal camera API at the kernel UAPI level. > That's where libcamera fits in. > > As for the pixel type, maybe use a floating-point type to avoid > range/precision problems? E.g. DRM_FORMAT_R32F for application > facing API. That format does not seem to exist yet, but it's > trivial to add into kernel's drm_fourcc.h and should be well > accepted IMO. > > > Thanks, > pq > > > > > [1]: > > https://www.guideir.com/products/mobileaccessories/mobirair/data_300.html > > [2]: https://github.com/tyalie/pyMobirAir-v4l2/ This link is broken :)
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