Ahh i see, thanks for the info! That all makes perfect sense! Sent from my iPad
On 20/05/2011, at 3:01 PM, Andrey Filippov <[email protected]> wrote: > > Nathan, > > These are "warm" pixels (ones that have increased dark current, their value > depends on the exposure time) - you may find such pixels on our panorama > images also. Most of the Aptina sensors we use have some number of warm and > even hot pixels (those that generate maximal output value regardless of the > exposure time) and the manufacturer does not offer different grades of the > sensors. Many cameras have built-in code to wipe such pixels out (replacing > their values by the average value from the neighbors) but we did not yet > implement such code in these cameras because most of the applications > involved some post-processing anyway and our main focus is to preserve the > actual sensor data in a reasonably "raw" form. So currently the only way to > eliminate such pixels is to do it with the post-processing. > > Additionally you will see less of the "warm" pixels if the exposure time goes > down from the 1/30 sec you have on those samples, only "hot" pixels will > remain. > > To measure the value of such pixels it is better to capture JP46 image (or > just monochrome), so each pixel will have the original value, not the one > mixed with the neighbors. > > You may find discussion on the warm pixels in the earlier posting: > > http://www.mail-archive.com/[email protected]/msg00113.html > > Andrey > > > On Thu, May 19, 2011 at 7:20 PM, Nathan Clark <[email protected]> wrote: > Hi Andrey, > > Here is a grab for you at full frame: > http://dl.dropbox.com/u/792881/Apertus%20Forum/Misc/RGB_Artifacts_2592x1936.jpg > > and one at 1024x768 > http://dl.dropbox.com/u/792881/Apertus%20Forum/Misc/RGB_Artifacts_1024x768.jpeg > > I have shot this with the iris closed down. As you can see, dotted all over > the place are little R/G/B hot pixels. > > I certainly hope we can fix this easily enough! > > Kind regards, > > Nathan. > > On Fri, May 20, 2011 at 7:47 AM, Andrey Filippov > <[email protected]> wrote: > Nathan, > > I'm sorry you have such artifacts. Can you please send the sample images from > the camera(s) with these artifacts? We test all the cameras before shipping > and it is very unlikely for the two cameras to have same hardware problems - > it might be something else. > > > Andrey > > > On Thu, May 19, 2011 at 10:38 AM, Nathan Clark <[email protected]> wrote: > Hi there, > > My partner and I just received 2 elphel 353 cameras. > I am noticing alarming artifacts appearing from both of them > (one camera more so than the other) > > It seems that scattered across the sensor- there are bright pixels- some Red, > some Green, and some Blue. These artifacts are constant and unmoving- and > become more obvious at lower resolutions. Is this a hardware fault for which > I should be seeking replacement? > > Before going that far, I thought I would consult with this list to see if > anyone has any ideas. If this is an uncommon problem, i can take grabs off > the sensor- or if this is a common problem- then you know what I'm talking > about. > > Kind regards, > Nathan > > > _______________________________________________ > Support-list mailing list > [email protected] > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com > > > > _______________________________________________ > Support-list mailing list > [email protected] > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com > > > > _______________________________________________ > Support-list mailing list > [email protected] > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com > > > _______________________________________________ > Support-list mailing list > [email protected] > http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com
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