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NASA's Mars probe: NO cmos, NO Bayer



 
 
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  #1  
Old May 28th 08, 03:53 AM posted to rec.photo.digital.slr-systems
Voodoo Thunder Pig
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Posts: 3
Default NASA's Mars probe: NO cmos, NO Bayer

RichA wrote:

from Amateur Photography magazine;

The camera has a double Gauss lens system, a design commonly used in
35mm cameras,' explains the space agency.
'Images are recorded by a charge-coupled device (CCD) similar to those
in consumer digital cameras. The instrument includes sets of red,
green and blue light-emitting diodes (LEDs) for illuminating the
target area.'

Nasa claims that the camera can focus down to 11mm and record images
at a resolution of '23 microns per pixel' at the closest focusing
distance - allowing the camera to show details 'much finer than the
width of a human hair'.



This means tri-colour imaging through three different filters onto a
monochrome CCD.


Nice try, Captain Obvious, but that's not what it means. It means the light
sources providethe three colors, and no filters are necessary.

  #2  
Old May 28th 08, 04:54 AM posted to rec.photo.digital.slr-systems
John O'Flaherty
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Posts: 82
Default NASA's Mars probe: NO cmos, NO Bayer

On Tue, 27 May 2008 19:53:23 -0700, Voodoo Thunder Pig
wrote:

RichA wrote:

from Amateur Photography magazine;

The camera has a double Gauss lens system, a design commonly used in
35mm cameras,' explains the space agency.
'Images are recorded by a charge-coupled device (CCD) similar to those
in consumer digital cameras. The instrument includes sets of red,
green and blue light-emitting diodes (LEDs) for illuminating the
target area.'

Nasa claims that the camera can focus down to 11mm and record images
at a resolution of '23 microns per pixel' at the closest focusing
distance - allowing the camera to show details 'much finer than the
width of a human hair'.



This means tri-colour imaging through three different filters onto a
monochrome CCD.


Nice try, Captain Obvious, but that's not what it means. It means the light
sources providethe three colors, and no filters are necessary.


Do you mean that the different colors of LEDs are on at different
times, providing color separation? I wonder if they might also use
filters on the LEDs, though, to increase spectral purity of the
colors.
But the critical question is, is it Nikon or Canon?
--
John
  #3  
Old May 28th 08, 07:55 AM posted to rec.photo.digital.slr-systems
Richard J Kinch
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Posts: 203
Default NASA's Mars probe: NO cmos, NO Bayer

John O'Flaherty writes:

But the critical question is, is it Nikon or Canon?


Polaroid.
  #4  
Old May 28th 08, 08:56 AM posted to rec.photo.digital.slr-systems
Chris Malcolm[_2_]
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Posts: 3,142
Default NASA's Mars probe: NO cmos, NO Bayer

John O'Flaherty wrote:
On Tue, 27 May 2008 19:53:23 -0700, Voodoo Thunder Pig
wrote:


RichA wrote:

from Amateur Photography magazine;

The camera has a double Gauss lens system, a design commonly used in
35mm cameras,' explains the space agency.
'Images are recorded by a charge-coupled device (CCD) similar to those
in consumer digital cameras. The instrument includes sets of red,
green and blue light-emitting diodes (LEDs) for illuminating the
target area.'

Nasa claims that the camera can focus down to 11mm and record images
at a resolution of '23 microns per pixel' at the closest focusing
distance - allowing the camera to show details 'much finer than the
width of a human hair'.



This means tri-colour imaging through three different filters onto a
monochrome CCD.


Nice try, Captain Obvious, but that's not what it means. It means the light
sources providethe three colors, and no filters are necessary.


Do you mean that the different colors of LEDs are on at different
times, providing color separation? I wonder if they might also use
filters on the LEDs, though, to increase spectral purity of the
colors.


Most unlikely. The problem with LEDs as light sources for photography
is that they're too spectrally pure.

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

  #5  
Old May 28th 08, 09:58 AM posted to rec.photo.digital.slr-systems
Colin_D[_2_]
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Posts: 218
Default NASA's Mars probe: NO cmos, NO Bayer

Voodoo Thunder Pig wrote:
RichA wrote:

from Amateur Photography magazine;

The camera has a double Gauss lens system, a design commonly used in
35mm cameras,' explains the space agency.
'Images are recorded by a charge-coupled device (CCD) similar to those
in consumer digital cameras. The instrument includes sets of red,
green and blue light-emitting diodes (LEDs) for illuminating the
target area.'

Nasa claims that the camera can focus down to 11mm and record images
at a resolution of '23 microns per pixel' at the closest focusing
distance - allowing the camera to show details 'much finer than the
width of a human hair'.



This means tri-colour imaging through three different filters onto a
monochrome CCD.


Nice try, Captain Obvious, but that's not what it means. It means the light
sources providethe three colors, and no filters are necessary.

I doubt that. What about ambient light? and the shots shown on the box
go out to infinity at the top of the vertical pan. Some leds!

The article says the sensor is similar to consumer digital cameras.
That means a Bayer matrix.

Colin D.
** Posted from http://www.teranews.com **
  #6  
Old May 28th 08, 12:40 PM posted to rec.photo.digital.slr-systems
John O'Flaherty
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Posts: 82
Default NASA's Mars probe: NO cmos, NO Bayer

On 28 May 2008 07:56:10 GMT, Chris Malcolm
wrote:

John O'Flaherty wrote:
On Tue, 27 May 2008 19:53:23 -0700, Voodoo Thunder Pig
wrote:


RichA wrote:

from Amateur Photography magazine;

The camera has a double Gauss lens system, a design commonly used in
35mm cameras,' explains the space agency.
'Images are recorded by a charge-coupled device (CCD) similar to those
in consumer digital cameras. The instrument includes sets of red,
green and blue light-emitting diodes (LEDs) for illuminating the
target area.'

Nasa claims that the camera can focus down to 11mm and record images
at a resolution of '23 microns per pixel' at the closest focusing
distance - allowing the camera to show details 'much finer than the
width of a human hair'.



This means tri-colour imaging through three different filters onto a
monochrome CCD.

Nice try, Captain Obvious, but that's not what it means. It means the light
sources providethe three colors, and no filters are necessary.


Do you mean that the different colors of LEDs are on at different
times, providing color separation? I wonder if they might also use
filters on the LEDs, though, to increase spectral purity of the
colors.


Most unlikely. The problem with LEDs as light sources for photography
is that they're too spectrally pure.


I didn't know that. There are more details and a picture of the
robotic arm camera and its light source here -
http://www.nasa.gov/mission_pages/ph...craft/rac.html
It mentions a 1:1 magnification with resulting resolution of 23
um/pixel, which doesn't seem very fine (cf. 2-3 um for a p&s or 6-7 um
for an SLR). Maybe the light output of the LEDs is so limited that
they need larger pixels to get a clean image; or, since the camera
probably had to be designed at least a few years ago to be ready for
the mission, it may be older technology.

There's also a "surface stereo imager" camera
http://www.nasa.gov/mission_pages/ph...craft/ssi.html
that has a 1000*1000 sensor. That one does use filters, "... but SSI
exceeds the capabilities of the human eye by using optical and
infrared filters, allowing multispectral imaging at 12 wavelengths of
geological interest and atmospheric interest."
I suppose that that one depends on sunlight, though, which is
broadband to start with.

Then there's at least one more camera, the microscope camera,
http://www.nasa.gov/mission_pages/ph...raft/meca.html
which resolves 4 um/pixel, with a field of view of 1*2mm (so about
250*500 pixels?). That one uses R,G,B, and UV LEDs.

--
John
  #7  
Old May 28th 08, 03:42 PM posted to rec.photo.digital.slr-systems
Wolfgang Weisselberg
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Posts: 5,285
Default NASA's Mars probe: NO cmos, NO Bayer

Chris Malcolm wrote:

Most unlikely. The problem with LEDs as light sources for photography
is that they're too spectrally pure.


NASA isn't interested in "photography" as we understand it,
except for PR.
They are interested in data --- and some of that data wants
spectrally relatively pure light.

-Wolfgang
  #8  
Old May 28th 08, 05:47 PM posted to rec.photo.digital.slr-systems
Dev/Null
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Posts: 56
Default NASA's Mars probe: NO cmos, NO Bayer


"John O'Flaherty" wrote in message
...

Do you mean that the different colors of LEDs are on at different
times, providing color separation? I wonder if they might also use
filters on the LEDs, though, to increase spectral purity of the
colors.
But the critical question is, is it Nikon or Canon?
--


Pentax/Samsung



  #9  
Old May 28th 08, 05:48 PM posted to rec.photo.digital.slr-systems
Dev/Null
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Posts: 56
Default NASA's Mars probe: NO cmos, NO Bayer


"Mark Sieving" wrote in message
...
On May 28, 6:51 am, RichA wrote:
On May 27, 10:53 pm, Voodoo Thunder Pig wrote:

RichA wrote:


This means tri-colour imaging through three different filters onto a
monochrome CCD.


Nice try, Captain Obvious, but that's not what it means. It means the
light
sources providethe three colors, and no filters are necessary.


Sure. Did the LEDs illuminate those horizon shots in colour too?
They must have some output.


The horizon shots are made with a different camera, the Surface Stereo
Imager. What you described is the Robotic Arm Camera, which is
strictly closeup.

Rich reads and comprehends only what he wants to!



  #10  
Old May 29th 08, 08:55 PM posted to rec.photo.digital.slr-systems
[email protected]
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Posts: 222
Default NASA's Mars probe: NO cmos, NO Bayer

Mark Sieving wrote:


The panoramic shots are made with the Surface Stereo Imager (SSI),
which is mounted on a mast extending above the spacecraft. This
imager has two sensors and two lens systems, to produce the stereo
images. Each sensor has a filter wheel containing twelve separate
filters, including a red filter and a blue filter (see
http://www.met.tamu.edu/mars/SSI_filter.html for details on the
filters). By combining images using two different filters, a false
color image can be produced, but the colors produced are not really
what the human eye would perceive.


Uh. Look closely: the right eye has filters at 447 or 450, 532, 603,
and 671 nm. This is perfectly adequate for full color inmagery.
The filters are a bit narrow band, but this is not terribly much a problem.

It is limited to two-color stereo.

Doug McDonald
 




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