From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp-68.nebula.fi ([83.145.220.68]:40890 "EHLO smtp-68.nebula.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752924Ab1IMMAl (ORCPT ); Tue, 13 Sep 2011 08:00:41 -0400 Date: Tue, 13 Sep 2011 15:00:36 +0300 From: Sakari Ailus To: Laurent Pinchart Cc: Subash Patel , linux-media@vger.kernel.org, s.nawrocki@samsung.com, hechtb@googlemail.com, g.liakhovetski@gmx.de Subject: Re: [RFC] New class for low level sensors controls? Message-ID: <20110913120036.GD1845@valkosipuli.localdomain> References: <20110906113653.GF1393@valkosipuli.localdomain> <4E68A5E7.8070800@gmail.com> <20110908114428.GC1724@valkosipuli.localdomain> <201109131233.59003.laurent.pinchart@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201109131233.59003.laurent.pinchart@ideasonboard.com> Sender: linux-media-owner@vger.kernel.org List-ID: On Tue, Sep 13, 2011 at 12:33:58PM +0200, Laurent Pinchart wrote: > Hi Sakari, > > 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? -- Sakari Ailus e-mail: sakari.ailus@iki.fi jabber/XMPP/Gmail: sailus@retiisi.org.uk