Problem With HDTV Images From Space Station

While waiting for the first live broadcast in HD from the international
space station I caught the first half of a program on the Apollo 11 trip
to the moon. One interesting aspect was the brief bright lights seen
in the cabin, later attributed to mysterious "Z" rays passing through it
(as I recall). They did not appear to do any damage, though. But
I watched the HD broadcast and noticed what appeared to be many
tiny white spots in the image which at first I thought were caused by
dust. On seeing a repeat of the program it was obvious that these
white spots could not be caused by dust in or on the lens, and their
sharpness and lightness probably precluded them from being caused
by dust on the sensors (and they did not change with light levels, but
they were clearly visible on my particularly sharp HD display at a
scale of about one pixel in two million). I wonder if "Z" rays (or
something similar) make shooting digitally in space difficult without
accepting some damage to the sensors (and the resultant images).
--
David Ruether


http://www.ferrario.com/ruether

Now you have me thinking....I saw the same HD episode from Discovery
HD while they were interviewing up in space and I could see the same
white spots. Was not pixelation nor a weak signal since they always
stayed in the same spot on the screen.


12/16/2006 11:14:55 AM
David Ruether wrote in message


While waiting for the first live broadcast in HD from the
international
space station I caught the first half of a program on the Apollo 11
trip
to the moon. One interesting aspect was the brief bright lights
seen
in the cabin, later attributed to mysterious "Z" rays passing
through it
(as I recall). They did not appear to do any damage, though. But
I watched the HD broadcast and noticed what appeared to be many
tiny white spots in the image which at first I thought were caused
by
dust. On seeing a repeat of the program it was obvious that these
white spots could not be caused by dust in or on the lens, and
their
sharpness and lightness probably precluded them from being caused
by dust on the sensors (and they did not change with light levels,
but
they were clearly visible on my particularly sharp HD display at a
scale of about one pixel in two million). I wonder if "Z" rays (or
something similar) make shooting digitally in space difficult
without
accepting some damage to the sensors (and the resultant images).
--
David Ruether


http://www.ferrario.com/ruether

"Ed Velez" wrote in message . ..
David Ruether wrote in message


While waiting for the first live broadcast in HD from the international
space station I caught the first half of a program on the Apollo 11 trip
to the moon. One interesting aspect was the brief bright lights seen
in the cabin, later attributed to mysterious "Z" rays passing through it
(as I recall). They did not appear to do any damage, though. But
I watched the HD broadcast and noticed what appeared to be many
tiny white spots in the image which at first I thought were caused by
dust. On seeing a repeat of the program it was obvious that these
white spots could not be caused by dust in or on the lens, and their
sharpness and lightness probably precluded them from being caused
by dust on the sensors (and they did not change with light levels, but
they were clearly visible on my particularly sharp HD display at a
scale of about one pixel in two million). I wonder if "Z" rays (or
something similar) make shooting digitally in space difficult without
accepting some damage to the sensors (and the resultant images).
--
David Ruether

Now you have me thinking....I saw the same HD episode from Discovery
HD while they were interviewing up in space and I could see the same
white spots. Was not pixelation nor a weak signal since they always
stayed in the same spot on the screen.

Yes. Aperture changes and light source position changes did not
make any difference, and the spots were very sharp and small (and
white) making dust on the sensors or lens unlikely. It seems that the
only possibility that remains is that the sensors were damaged. If
so, I wonder by what means - and if this really means that digital
photography in space has some basic problem associated with it...
--
David Ruether


http://www.ferrario.com/ruether

"David Ruether" wrote in message
...

While waiting for the first live broadcast in HD from the international
space station I caught the first half of a program on the Apollo 11 trip
to the moon. One interesting aspect was the brief bright lights seen
in the cabin, later attributed to mysterious "Z" rays passing through it
(as I recall). They did not appear to do any damage, though. But
I watched the HD broadcast and noticed what appeared to be many
tiny white spots in the image which at first I thought were caused by
dust. On seeing a repeat of the program it was obvious that these
white spots could not be caused by dust in or on the lens, and their
sharpness and lightness probably precluded them from being caused
by dust on the sensors (and they did not change with light levels, but
they were clearly visible on my particularly sharp HD display at a
scale of about one pixel in two million). I wonder if "Z" rays (or
something similar) make shooting digitally in space difficult without
accepting some damage to the sensors (and the resultant images).
--
David Ruether


http://www.ferrario.com/ruether


Those spots were defects in the HD CCD. Hot Pixels if you want. Most
consumer and professional cameras have software built in to correct for
defects in the CCDs but NASA does not want this pixel correction software on
any of their cameras. They expect to do any correction they want on the
ground. This way they have true Raw images from the HD CCD that in case they
need to very carefully analyze the data at a later date they will have the
'original' raw video.


NM

"~~NoMad~~" wrote in message
...

"David Ruether" wrote in message
...

While waiting for the first live broadcast in HD from the international
space station I caught the first half of a program on the Apollo 11 trip
to the moon. One interesting aspect was the brief bright lights seen
in the cabin, later attributed to mysterious "Z" rays passing through it
(as I recall). They did not appear to do any damage, though. But
I watched the HD broadcast and noticed what appeared to be many
tiny white spots in the image which at first I thought were caused by
dust. On seeing a repeat of the program it was obvious that these
white spots could not be caused by dust in or on the lens, and their
sharpness and lightness probably precluded them from being caused
by dust on the sensors (and they did not change with light levels, but
they were clearly visible on my particularly sharp HD display at a
scale of about one pixel in two million). I wonder if "Z" rays (or
something similar) make shooting digitally in space difficult without
accepting some damage to the sensors (and the resultant images).
--
David Ruether


http://www.ferrario.com/ruether


Those spots were defects in the HD CCD. Hot Pixels if you want. Most
consumer and professional cameras have software built in to correct for
defects in the CCDs but NASA does not want this pixel correction software
on any of their cameras. They expect to do any correction they want on the
ground. This way they have true Raw images from the HD CCD that in case
they need to very carefully analyze the data at a later date they will
have the 'original' raw video.


NM

And BTW: This is an excellent example of what a typical CCD in a camera or
camcorder would look like if it didn't have pixel correction software.

NM

"~~NoMad~~" wrote in message ...
"~~NoMad~~" wrote in message ...
"David Ruether" wrote in message ...

While waiting for the first live broadcast in HD from the international
space station I caught the first half of a program on the Apollo 11 trip
to the moon. One interesting aspect was the brief bright lights seen
in the cabin, later attributed to mysterious "Z" rays passing through it
(as I recall). They did not appear to do any damage, though. But
I watched the HD broadcast and noticed what appeared to be many
tiny white spots in the image which at first I thought were caused by
dust. On seeing a repeat of the program it was obvious that these
white spots could not be caused by dust in or on the lens, and their
sharpness and lightness probably precluded them from being caused
by dust on the sensors (and they did not change with light levels, but
they were clearly visible on my particularly sharp HD display at a
scale of about one pixel in two million). I wonder if "Z" rays (or
something similar) make shooting digitally in space difficult without
accepting some damage to the sensors (and the resultant images).
--
David Ruether

Those spots were defects in the HD CCD. Hot Pixels if you want. Most consumer and professional cameras have software built in to
correct for defects in the CCDs but NASA does not want this pixel correction software on any of their cameras. They expect to do
any correction they want on the ground. This way they have true Raw images from the HD CCD that in case they need to very
carefully analyze the data at a later date they will have the 'original' raw video.

NM

And BTW: This is an excellent example of what a typical CCD in a camera or camcorder would look like if it didn't have pixel
correction software.

NM

Ah, your explanation seems entirely logical, especially given the apparent
single-pixel size of the spots. Thanks.
--
David Ruether


http://www.ferrario.com/ruether

~~NoMad~~ wrote:

edited, for brevity

Those spots were defects in the HD CCD. Hot Pixels if you want. Most
consumer and professional cameras have software built in to correct for
defects in the CCDs but NASA does not want this pixel correction software
on any of their cameras. They expect to do any correction they want on the
ground. This way they have true Raw images from the HD CCD that in case
they need to very carefully analyze the data at a later date they will
have the 'original' raw video.


NM

And BTW: This is an excellent example of what a typical CCD in a camera or
camcorder would look like if it didn't have pixel correction software.

NM


Hello, NoMad:

My Kodak P850 digicam has a few bad pixels. It's still under warranty,
but If I decided to exchange it, what are the odds that I'd get a camera
with a "perfect" CCD?

Is there anything else I could do, perhaps?

Thanks!


Cordially,
John Turco

"John Turco" wrote in message
...
~~NoMad~~ wrote:

edited, for brevity

Those spots were defects in the HD CCD. Hot Pixels if you want. Most
consumer and professional cameras have software built in to correct for
defects in the CCDs but NASA does not want this pixel correction
software
on any of their cameras. They expect to do any correction they want on
the
ground. This way they have true Raw images from the HD CCD that in case
they need to very carefully analyze the data at a later date they will
have the 'original' raw video.


NM

And BTW: This is an excellent example of what a typical CCD in a camera
or
camcorder would look like if it didn't have pixel correction software.

NM


Hello, NoMad:

My Kodak P850 digicam has a few bad pixels. It's still under warranty,
but If I decided to exchange it, what are the odds that I'd get a camera
with a "perfect" CCD?

Is there anything else I could do, perhaps?


If you send it back to the factory they may to decide to run special
software on it that maps out the bad pixels. I've heard of cases where CCDs
actually deteriorate after manufacture and new bad pixels form. This
condition seems very rare. Usually when the bad pixels are mapped out they
stay clear for the future.

NM

In article ,
David Ruether wrote:
"~~NoMad~~" wrote in message ...
And BTW: This is an excellent example of what a typical CCD in a camera or camcorder would look like if it didn't have pixel
correction software.

Ah, your explanation seems entirely logical, especially given the apparent
single-pixel size of the spots. Thanks.

It doesn't make all that much sense to me.

In 'normal' 3CCD video camera, a stuck pixel is just one primary color.
For some reason it is usually blue (I guess the blue signal is amplified
more, but I am not sure).

On a Bayer pattern sensor it not clear what would happen. But I don't
expect a single stuck pixel to be always white.

Of a scanning back with a filter wheel, I expect a stuck pixel to be white,
but I doubt NASA uses those types of cameras for HDTV.


--
That was it. Done. The faulty Monk was turned out into the desert where it
could believe what it liked, including the idea that it had been hard done
by. It was allowed to keep its horse, since horses were so cheap to make.
-- Douglas Adams in Dirk Gently's Holistic Detective Agency

"Philip Homburg" wrote in message
.phicoh.net...
In article ,
David Ruether wrote:
"~~NoMad~~" wrote in message
...
And BTW: This is an excellent example of what a typical CCD in a camera
or camcorder would look like if it didn't have pixel
correction software.

Ah, your explanation seems entirely logical, especially given the apparent
single-pixel size of the spots. Thanks.

It doesn't make all that much sense to me.

In 'normal' 3CCD video camera, a stuck pixel is just one primary color.
For some reason it is usually blue (I guess the blue signal is amplified
more, but I am not sure).

On a Bayer pattern sensor it not clear what would happen. But I don't
expect a single stuck pixel to be always white.

Of a scanning back with a filter wheel, I expect a stuck pixel to be
white,
but I doubt NASA uses those types of cameras for HDTV.


I expect that if NASA wanted their HD camera to be a high-precision
instrument capable of registering a most accurate image that they would use
a single CCD camera with filter wheel. This way the camera could be
carefully characterized and they would know exactly where each good pixel is
pointing.

NM

P.S. NASA has always been known for using high precision, large dynamic
range B&W sensors that use filters to extract color data.