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maemo.org - Talk (https://talk.maemo.org/index.php)
-   Nokia N900 (https://talk.maemo.org/forumdisplay.php?f=44)
-   -   Front [web] Camera Noise (https://talk.maemo.org/showthread.php?t=40640)

Dak 2010-01-15 06:13
Re: Front [web] Camera Noise
 
I would like confirmation on that...every tech spec I have seen has described the front camera as a 640x480 VGA camera.

If it isn't, it's going straight back to Amazon/Nokia for a refund.

manda 2010-01-15 06:29
Re: Front [web] Camera Noise
 
Quote:
Originally Posted by uris (Post 473192)
Sorry, got it 'work' when initiating video chat from laptop towards N900.
With MacOSX 10.5.11 and Firefox with latest Google talk plug-in video starts for couple of seconds but then chrashes.
This is a known bug. It will be fixed in PR1.2 firmware.

ossipena 2010-01-15 06:37
Re: Front [web] Camera Noise
 
Quote:
Originally Posted by Dak (Post 473156)
Just to be clear, I'm not suggesting that the camera doesn't work....it works just fine....I'm concerned about the abysmal quality of the image.

@Alex - I'm aware of post-processing, but surely the raw image data shouldn't be this bad? Even when I completely cover the camera with my thumb, I don't see a flat black image...I see the same noise!

All I want to know is the hard technical truth....
back to the school. educate yourself a bit with topic "photosensitive sensors"

and spoiler: the darker the image, the more visible the noise (because there isn't enough light to get sensed by sensor so all you see is the background noise. background noise is a feature of digital sensors)

benny1967 2010-01-15 09:01
Re: Front [web] Camera Noise
 
Quote:
Originally Posted by oscillik (Post 473139)
fact is: the camera is supposed to be there for a reason,
I wouldn't be too sure about this:
Both the N800 and the N810 hab a front facing cam. None of them had much practical value. I could get a video chat working with my N810 only a few weeks before the N900 was announced - and it required software on the other end that few people have installed.

So looking at this 3-year-history of useless front cams, I wouldn't be too surprised if the one on the N900 served no purpose at all. ;)

Dragy 2010-01-15 10:02
Re: Front [web] Camera Noise
 
I noticed the poor quality as well... shame, this is my first device with a front camera, I expected to use it as a mirror (as the app offers) but it's really hard to see anything clear really. Do you guys think maybe it's the plastic cover of the front camera that's too dark?

attila77 2010-01-15 11:02
Re: Front [web] Camera Noise
 
Quote:
Originally Posted by ossipena (Post 473297)
and spoiler: the darker the image, the more visible the noise (because there isn't enough light to get sensed by sensor so all you see is the background noise. background noise is a feature of digital sensors)
In the end it comes down to signal-to-noise. The default gain is quite low, I have to gamma-boost it for people to see *anything* indoors. That's the main source of noise - with default settings it's not that noisy, except you can't see anything. I already experimented with hooking up the noise reduction elements from the main cam to see if it can help mirror, but there seem to be some hard-coded values in there which make this difficult to do in a way accessible to users (and since it's a Nokia license I can't even clone/tweak it as another element).

EDIT: I *could* trade resolution for less noise, e.g. get 320x240 via binning (this is not the same as recording in 320x240 !), but that's a lot of CPU usage there unless I can harness the DSP.

Renkon 2010-01-15 11:03
Re: Front [web] Camera Noise
 
Do you also have some "sticky" RGB pixels with the camera? The noise is obvious, but those are strange.

Edit: Now that's funny. These aren't really stuck pixels but they're more rectangles with a black pixel inside oO

attila77 2010-01-15 11:07
Re: Front [web] Camera Noise
 
Yeah, those are hot pixels. As they are quite prominent, it seems that there is little postprocessing done on the raw image.

Renkon 2010-01-15 11:18
Re: Front [web] Camera Noise
 
Quote:
These aren't really stuck pixels but they're more rectangles with a black pixel inside
Must be the upscaling algorithm. Every "pixel" shown is a rectangle...

attila77 2010-01-15 11:44
Re: Front [web] Camera Noise
 
That can be a result of the bayer demosaicing, too, though. Or a combination (like the original hot pixel being removed AFTER demosaicing).


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