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List:       kde-core-devel
Subject:    Re: GSoC: automatic brightness adjustment
From:       Mike Dean <miketdean () gmail ! com>
Date:       2012-04-05 5:32:19
Message-ID: CAH3haxLLgLn1OJ1PRgE5sX3A3gceqm3HGkBM4ox_YpSeB7Ejmg () mail ! gmail ! com
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As an electrical engineer, I find this idea sound.  With a low sampling
rate, such as 0.5 Hz (once every 2 seconds), the additional power draw
should be negligible.  1/60th Hz is far too slow to produce enough quality
for users to appreciate it.  0.5 Hz should be considered a minimum.  While
the computer is plugged in, an effective sampling rate of 5 Hz or better
would provide very nice quality.  In hardware, we low pass filter the
output from the sensor to stabilize the display brightness.  In software,
you would do this by averaging the samples.

Incidentally, this is a feature I've wished would make it into Linux
desktops for quite some time now.


On Wed, Apr 4, 2012 at 9:37 PM, dE . <de.techno@gmail.com> wrote:

>  On 04/04/12 20:00, Vadim Dombrowski wrote:
>
> Thanks for reply!
>
> I agree that keeping web-cam always on is not a good idea. Actually it may
> prevent some real applications, such as Skype to use web-cam. I think about
> making a shots every minute for example. That partially solves the problem
> with power.
> On Apr 4, 2012 3:48 PM, "Dario Freddi" <drf54321@gmail.com> wrote:
>
>> Hi,
>>
>> Il 04 aprile 2012 03:12, Vadim Dombrowski <pftbest@gmail.com> ha scritto:
>> >  Hi!
>> >
>> > I'm a student of Belarusian State University and I would like to
>> > participate in GSoC 2012.
>> >
>> > The idea for my project is to create an automatic brightness
>> > adjustment mechanism using web-camera as light sensor.
>> > Today a lot of laptops have integrated web-camera, but don't have any
>> > light sensor. So you should manually change brightness every time the
>> > ambient light changes.
>> > Using web-camera as light sensor should give enough information to do
>> > automatic adjustment.
>> >
>> > So I am interested whether this is a good idea? And if it is, how can
>> > I find/contact mentor or team related to brightness in KDE?
>>
>> I would be your best contact point for it probably. I admit I am not
>> really fond of the idea - keeping the webcam on and busy all of the
>> time to make it act like an (inaccurate) light sensor is quite a waste
>> of resources to me, and most laptop users would rather live without
>> auto-adjustment than with 1 hour less of battery. A proposal about
>> integrating light sensors (and maybe more hw capabilities) would be
>> instead much more interesting from my POV.
>>
>> >
>> > Best regards,
>> > Vadim Dombrovski.
>>
>
> Yes, as a user, I find this to be a good idea.
>

[Attachment #3 (text/html)]

As an electrical engineer, I find this idea sound.  With a low sampling rate, such as \
0.5 Hz (once every 2 seconds), the additional power draw should be negligible.  \
1/60th Hz is far too slow to produce enough quality for users to appreciate it.  0.5 \
Hz should be considered a minimum.  While the computer is plugged in, an effective \
sampling rate of 5 Hz or better would provide very nice quality.  In hardware, we low \
pass filter the output from the sensor to stabilize the display brightness.  In \
software, you would do this by averaging the samples.<div>

<br></div><div>Incidentally, this is a feature I&#39;ve wished would make it into \
Linux desktops for quite some time now.</div><div><br><br><div class="gmail_quote">On \
Wed, Apr 4, 2012 at 9:37 PM, dE . <span dir="ltr">&lt;<a \
href="mailto:de.techno@gmail.com">de.techno@gmail.com</a>&gt;</span> wrote:<br>

<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex">  
    
  
  <div bgcolor="#FFFFFF" text="#000000"><div><div class="h5">
    On 04/04/12 20:00, Vadim Dombrowski wrote:
    <blockquote type="cite">
      <p>Thanks for reply!</p>
      <p>I agree that keeping web-cam always on is not a good idea.
        Actually it may prevent some real applications, such as Skype to
        use web-cam. I think about making a shots every minute for
        example. That partially solves the problem with power.</p>
      <div class="gmail_quote">On Apr 4, 2012 3:48 PM, &quot;Dario Freddi&quot;
        &lt;<a href="mailto:drf54321@gmail.com" \
                target="_blank">drf54321@gmail.com</a>&gt; wrote:<br \
                type="attribution">
        <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc \
solid;padding-left:1ex">  Hi,<br>
          <br>
          Il 04 aprile 2012 03:12, Vadim Dombrowski &lt;<a \
href="mailto:pftbest@gmail.com" target="_blank">pftbest@gmail.com</a>&gt; ha \
scritto:<br>  &gt;  Hi!<br>
          &gt;<br>
          &gt; I&#39;m a student of Belarusian State University and I would
          like to<br>
          &gt; participate in GSoC 2012.<br>
          &gt;<br>
          &gt; The idea for my project is to create an automatic
          brightness<br>
          &gt; adjustment mechanism using web-camera as light sensor.<br>
          &gt; Today a lot of laptops have integrated web-camera, but
          don&#39;t have any<br>
          &gt; light sensor. So you should manually change brightness
          every time the<br>
          &gt; ambient light changes.<br>
          &gt; Using web-camera as light sensor should give enough
          information to do<br>
          &gt; automatic adjustment.<br>
          &gt;<br>
          &gt; So I am interested whether this is a good idea? And if it
          is, how can<br>
          &gt; I find/contact mentor or team related to brightness in
          KDE?<br>
          <br>
          I would be your best contact point for it probably. I admit I
          am not<br>
          really fond of the idea - keeping the webcam on and busy all
          of the<br>
          time to make it act like an (inaccurate) light sensor is quite
          a waste<br>
          of resources to me, and most laptop users would rather live
          without<br>
          auto-adjustment than with 1 hour less of battery. A proposal
          about<br>
          integrating light sensors (and maybe more hw capabilities)
          would be<br>
          instead much more interesting from my POV.<br>
          <br>
          &gt;<br>
          &gt; Best regards,<br>
          &gt; Vadim Dombrovski.<br>
        </blockquote>
      </div>
    </blockquote>
    <br></div></div>
    Yes, as a user, I find this to be a good idea.<br>
  </div>

</blockquote></div><br></div>



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