Hi Sakari, On Tuesday 13 September 2011 14:00:36 Sakari Ailus wrote: > On Tue, Sep 13, 2011 at 12:33:58PM +0200, Laurent Pinchart wrote: > > On Thursday 08 September 2011 13:44:28 Sakari Ailus wrote: > > > On Thu, Sep 08, 2011 at 04:54:23PM +0530, Subash Patel wrote: > > > > On 09/06/2011 05:52 PM, Sakari Ailus wrote: > > > > > On Tue, Sep 06, 2011 at 01:41:11PM +0200, Laurent Pinchart wrote: > > > > > > Other controls often found in bayer sensors are black level > > > > > > compensation and test pattern. > > > > > > > > Does all BAYER sensor allow the dark level compensation programming? > > > > > > I'm not sure. I have always seen ISPs being used for that, not sensors. > > > > > > > I thought it must be auto dark level compensation, which is done by > > > > the sensor. The sensor detects the optical black value at start of > > > > each frame, and analog-to-digital conversion is shifted to > > > > compensate the dark level for that frame. Hence I am thinking if > > > > this should be a controllable feature. > > > > > > This is probably what smart sensors could do. If we have a raw bayer > > > sensor the computation of the optimal black level compensation could > > > be done by some of the controls algorithms run in the user space. > > > Automatic exposure probably? > > > > Many "non-smart" raw bayer sensors implement both manual and automatic > > black level compensation. In the first case the user programs a value to > > be subtracted from the pixels (whether that's done in the analog or > > digital domain might be sensor-specific), and in the second case the > > sensor computes a mean black level value based on black lines (optically > > unexposed) at the top of the image. > > Sounds like two controls to me, right? At least two, an auto control and a manual value control. Additional controls (such as the number of lines on which to compute the black level average automatically for instance, or a read-only control to report the computed average) will probably be added later. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
