Hello, On Tue, Jan 10, 2023 at 12:45:18PM +0100, Jacopo Mondi via libcamera-devel wrote: > On Tue, Jan 10, 2023 at 10:46:26AM +0200, Pekka Paalanen wrote: > > On Sat, 7 Jan 2023 22:58:41 +0100 Sophie Friedrich 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 ? >From a quick glance at the github project linked below, it doesn't seem to be a UVC camera. Sophie, could you please share the `lsusb -v` output for the device (you can limit it to a specific device with `-d VID:PID`), running as root (e.g. with `sudo`) if possible ? > 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. > > > > > [1]: https://www.guideir.com/products/mobileaccessories/mobirair/data_300.html > > > [2]: https://github.com/tyalie/pyMobirAir-v4l2/ > > This link is broken :) Works for me. -- Regards, Laurent Pinchart
