Nice first images
Adam Dybbroe
ftp://ftp.ssec.wisc.edu/pub/incoming
I have looked at:
viirs_true_20111122_t05_enh.jpg
viirs_true_20111121_t16_enh.jpg
viirs_true_20111121_t18_enh.jpg
Really amazing!
A question:
The stripes you see in some parts (see my cropped image attached) I
would refer to the infamous "cross talk" experienced/expected on the
visible (ocean colour) channels. Is that a correct imterpretation you think?
Further to the subject of cross talk, as I understand it: It is the
effect observed when one channel on one sensor (we have 16 M band
sensors in one scan on VIIRS) is contaminated with a signal from another
channel in a "nearby" sensor. Is that a correct explanation? I am quite
unfamiliar with the issue!
Best regards
Adam
Scheirer Ronald
I'm not sure if these are M-Band images, we are looking at. Probabbly not.
By mid of December we will see IR channels also. This will be interesting, I guess.
I have no idea, what the stripes are from. You need to know more details about the sensor. But in theory one could say, that if the stripes are across scan direction it might be because of memory effects (kind of crosstalk in time). Along scan could indicate spatial crosstalk from sensor to sensor.
You normally try to avoid travelling signals from one channel to another by arranging channels on the focal plane close to other channel which are expected to feature a low contrast.
So these are all different types of blurring mechanisms.
All the best
Rolle
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Från: npp-sa...@googlegroups.com [mailto:npp-sa...@googlegroups.com] För Adam Dybbroe
Skickat: den 23 november 2011 15:56
Till: npp-sa...@googlegroups.com
Ämne: Nice first images
Adam Dybbroe
On 2011-11-23 17:45, Scheirer Ronald wrote:
> Hej Adam,
> I'm not sure if these are M-Band images, we are looking at. Probabbly not.
To me the image viirs_true_20111121_t16_enh.jpg looks pretty close to a
true color RGB, and not something you could do with only the broad I-bands.
It would be easy to ask, and save us time speculating.
> By mid of December we will see IR channels also. This will be interesting, I guess.
>
Yes.
> I have no idea, what the stripes are from. You need to know more details about the sensor. But in theory one could say, that if the stripes are across scan direction it might be because of memory effects (kind of crosstalk in time). Along scan could indicate spatial crosstalk from sensor to sensor.
I am not sure I follow you completely.
The stripes I see are along scan. The 16/32 bands are scanned
simultaneously, right? So if one sensor leaks to another I would expect
such stripes.
Would be nice with a basic course in VIIRS sensor physics!
> You normally try to avoid travelling signals from one channel to another by arranging channels on the focal plane close to other channel which are expected to feature a low contrast.
Yes, I know. But we also know that VIIRS have failed to meet
specifications on some bands concerning cross-talk, thats why I bring it up.
-Adam