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08-18-2010, 11:13 AM   #1
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Just out of curiosity, what happens during pixel mapping?

During my sensor cleaning adventures I discovered a stuck or dead pixel on my sensor (i.e. a single red in every shot that enlarged when zoomed in on). I read somewhere that in cases like this you should run the pixel mapping function. I did this and the issue has been resolved. However this led me to wonder what actually transpires when you run the pixel mapping function. Is it defective pixel detected and masked without being "fixed" or does the sensor somehow coerce the pixel back into functionality? The latter seems unlikely as the sensor is a passive component. I realize that this might be too technical of a question, the answer of which doesn't actually matter, but I just can't let it sit.

Ian G

08-18-2010, 11:39 AM   #2
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The pixel is "mapped" in the software, and the software fixes it for you automatically while processing the image

Stuck pixels can generally only be fixed on LCD screens, by massaging or flashing them rapidly.

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08-18-2010, 12:17 PM   #3

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Adam, I've had the same question and still don't understand what "fixes" or "processing" mean in your reply. I'm sure most on the forum know that but I'm afraid I don't.

What is the fix? For example, do you mean that the camera's software replaces the input from a single sensor site with some fixed value prior to demosaicing or perhaps that the software interpolates a value each time from the surrounding sites or perhaps that some other action takes place?

Is this "fix" done prior to creating the raw file or in the raw ===> JPEG stage?

It's clear that I don't need the "confused" icon.
08-18-2010, 02:18 PM   #4
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One pixel tells another pixel the way home, cos he was lost.


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