Camera support for Circle

[rsta2]

There is some initial camera support for Circle in the new libcamera project. Because of license reasons, I created a separate project, which has reached an appropriate stage now to refer to it. Please read the main project README for more info.

Implementing camera support is normally not a small task and needs much knowledge about image processing topics. Personally, I'm better in writing hardware drivers than implementing algorithms to improve the quality of captured images. Currently libcamera has drivers for the official Camera Modules 1 and 2 (with OV5647 and IMX219 sensors) and for the CSI-2 interface of the Raspberry Pi.

There is an implementation of a White Balance algorithm too, but currently it can be only used for still images, because in a live image it's flickering. This is more a problem with the Camera Module 2, because the Camera Module 1 supports Auto Gain Control and White Balance in hardware. There is no Auto Gain and Exposure Control for the Compute Module 2 at the moment.

So if you have image processing knowledge and you want to help to improve the camera support for Circle, you are invited to do so.