«

See:

http://earthobservatory.nasa.gov/New...3?img_id=18114

David

"Rita Berkowitz" <> wrote in message
news: m...
> David J Taylor wrote:
>
>> See:
>>
>>
>> http://earthobservatory.nasa.gov/New...3?img_id=18114
>
> Looks more like a dirty public toilet seat than a bird's nest. Cool pic.

A subject of expertise, no doubt, for you.

Pretty telling reply, dontcha think?

the chinese somehow censored the colour!

bye


frank



http://tvc15.blogs.com/

On Wed, 13 Aug 2008 17:30:32 -0500, Ron Hunter <> wrote:
: Allen wrote:
: > Frank wrote:
: >> the chinese somehow censored the colour!
: >>
: >> bye
: >>
: >>
: >> frank
: >>
: >>
: >>
: >> http://tvc15.blogs.com/
: >>
: >>
: > But is it a disguised missile silo? If it were in Iraq, Duh Bya would
: > be shouting "There's the proof! There's the proof!"
: > Allen
: Please keep your politics to yourself.

Why? Does the truth about the Republican Agenda offend your sensibilities?
You're not planning to vote for Cain McLain, are you? ;^)

Bob

Rita Berkowitz <> wrote:
> B?wser wrote:

>>>> http://earthobservatory.nasa.gov/New...3?img_id=18114
>>>
>>> Looks more like a dirty public toilet seat than a bird's nest. Cool
>>> pic.
>>
>> A subject of expertise, no doubt, for you.
>>
>> Pretty telling reply, dontcha think?

> Let's see? Air pollution that limits visibility to less than 100-meters,

Just what distance do you think the photograph you are "discussing"
was taken from?

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

John McWilliams wrote:
[]
> Wonder why photo is in B+W?

Most satellite data is single channel - less bandwidth and perhaps higher
resolution - colour is false-colour obtained by combining separate RGB
channels. If those channels approximate to a human eye response, the
result is natural colour images. Usually, though, you would expect a
three-channel scan for "public consumption" images. Perhaps in this case
the commercial image /is/ in colour?

David

Ron Hunter wrote:
> David J Taylor wrote:
>> John McWilliams wrote:
>> []
>>> Wonder why photo is in B+W?
>>
>> Most satellite data is single channel - less bandwidth and perhaps
>> higher resolution - colour is false-colour obtained by combining
>> separate RGB channels. If those channels approximate to a human eye
>> response, the result is natural colour images. Usually, though, you
>> would expect a three-channel scan for "public consumption" images.
>> Perhaps in this case the commercial image /is/ in colour?
>>
>> David
>>
>>
> Interesting that you call the way your eyes sense color, and the way
> almost all digital cameras do it, as 'false color'.

Ron,

I'm more used to dealing with satellite data where the colour is produced
from channels with sensitive wavelengths far removed from those of the
human eye - hence the colour is false. Even with the Digital Globe
satellite, I would expect that the RGB channels are not chosen to
specifically match the colour standards in digital photography RGB space
(sRGB, ARGB etc.), so "approximate colour" might be a better description
than "false-colour". But you are right in that all digital photography is
"approximate colour".

If anyone has an example which is not "approximate", let him speak now!

Cheers,
David

David J Taylor <david-> wrote:
> Ron Hunter wrote:
>> David J Taylor wrote:
>>> John McWilliams wrote:
>>> []
>>>> Wonder why photo is in B+W?
>>>
>>> Most satellite data is single channel - less bandwidth and perhaps
>>> higher resolution - colour is false-colour obtained by combining
>>> separate RGB channels. If those channels approximate to a human eye
>>> response, the result is natural colour images. Usually, though, you
>>> would expect a three-channel scan for "public consumption" images.
>>> Perhaps in this case the commercial image /is/ in colour?
>>>
>>> David
>>>
>>>
>> Interesting that you call the way your eyes sense color, and the way
>> almost all digital cameras do it, as 'false color'.

> Ron,

> I'm more used to dealing with satellite data where the colour is produced
> from channels with sensitive wavelengths far removed from those of the
> human eye - hence the colour is false. Even with the Digital Globe
> satellite, I would expect that the RGB channels are not chosen to
> specifically match the colour standards in digital photography RGB space
> (sRGB, ARGB etc.), so "approximate colour" might be a better description
> than "false-colour". But you are right in that all digital photography is
> "approximate colour".

> If anyone has an example which is not "approximate", let him speak now!

A most amusing exercise with your digital camera is to split a sunbeam
with a glass prism and catch the resulting spectrum on a white piece
of paper. Annotate the paper in pencil with where you consider the
boundaries between the colours are. Then photograph it all with your
digital camera and look at the result

--
Chris Malcolm DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
[http://www.dai.ed.ac.uk/homes/cam/]

Ron Hunter wrote:
[]
> I am sure there are instruments that can measure color to an exact
> wavelength, but the human eye, the only reference I really can depend
> on, isn't one of them, being, inherently analog. I am familiar with
> colors being manipulated to distinguish, for instance, growing
> vegetation, from dead vegetation, which are called 'false color' to
> denote this manipulation. Perhaps 'visible wavelengths' would be a
> better designation than 'approximate color' in this case (or colour,
> if you prefer).

Yes, Ron, "visible wavelength" sensors could be a suitable description.
Be aware, though, that satellites sometimes have more than just the three
RGB visible wavelength colour sensors we are used to with digital cameras.
How do you process more than three colours to a three colour display
without some element of approximation?

Cheers,
David