IKONOS image sensor, 115 million pixels
ch...@csua.berkeley.edu
The IKONOS imaging satellite boosts 115 million image pixels per
second image gathering capability.
http://www.birdseyeimages.com/camera.html
If a 35mm digital SLR hosts such image sensor (say in the future),
what kind of resolution can we expect out of it? How big the tiff/jpg
be?
What kind of magnification can we expect from such sensor? If I take a
picture of someone, will I see the individual molecules on their face? :)
8756x13133x3 = 345mb. So each CD will fit 1-2 uncompressed images. Neat.
Actually comparing to 1200x1600, it's about 8x magnification... is
that right?
--
Raymond Chi
ch...@csua.Berkeley.EDU
Marvin Margoshes
camera would be proportionally larger, that is about 315 Mb.
<ch...@csua.Berkeley.EDU> wrote in message
news:9nredf$13f2$1...@agate.berkeley.edu...
Don Stauffer
N is the number of pixels.
I do not know about the IKONOS camera specifically, but similar cameras
I have worked on use a linear array instead of a 2-D mosaic. The array
is then mechanically scanned in the other direction.
In fact, I have a friend who had an 8 x 10 view camera. He mounted it
above a flatbed scanner and turned the scanner/camera into an 8 x 10
digital camera. For a kludged up setup it actually worked quite well.
In such a setup, the number of actual photocells needed is approximately
the square root of the total image pixel count.
--
Don Stauffer in Minnesota
stau...@usfamily.net
webpage- http://www.usfamily.net/web/stauffer
Dave Martindale
>The IKONOS imaging satellite boosts 115 million image pixels per
>second image gathering capability.
That's "pixels per second". There's no sensor in there with 115 million
pixel positions.
Almost always, the camera on this sort of device is a linear array of
photosensors oriented perpendicular to the satellite's own motion.
The linear array is electronically scanned to obtain one direction of
the image raster. The motion of the satellite causes the earth's
image to sweep by the sensor in the other direction, and that plus
the time delay between successive scans provides the other direction
of the image raster.
So a satellite camera is a lot like a flatbed scanner, but has very
little in common with a standard digital camera with a 2D sensor.
The satellite "camera" has a resolution that's probably about 8000x1
if you look at it at a single point in time, or a resolution that's
8000 by infinity if looked at over all time.
>If a 35mm digital SLR hosts such image sensor (say in the future),
>what kind of resolution can we expect out of it? How big the tiff/jpg
>be?
You wouldn't want such a sensor in an ordinary SLR, because you couldn't
use a shutter to stop motion. Linear sensors *are* used in some specialized
cameras used for "still life" photography, where it doesn't matter that
it takes a minute or so to acquire the whole image.
>8756x13133x3 = 345mb. So each CD will fit 1-2 uncompressed images. Neat.
Yeah, but the people using this sort of camera probably aren't archiving
onto CD.
>Actually comparing to 1200x1600, it's about 8x magnification... is
>that right?
Yes, that's right - depending on how you define magnification.
Dave
Kevin McMurtrie
"Marvin Margoshes" <physche...@telocity.com> wrote:
>A tiff file from a 3.3 Mp camera is about 9 Mb. The file from a 115 Mb
>camera would be proportionally larger, that is about 315 Mb.
>
[snip]
The 3x difference between digicam megapixels and TIFF is because each
camera pixel senses one color. An algorithm runs over the CCD color
pattern interpolates what the the other two color color values are
likely to be for each pixel.
The linear CCDs I've seen have a row of red, green, and blue sensors.
The colors have to be re-aligned in software but there's no
interpolation.
Erik Harris
> second image gathering capability.
>
> http://www.birdseyeimages.com/camera.html
>
> If a 35mm digital SLR hosts such image sensor (say in the future),
> what kind of resolution can we expect out of it? How big the tiff/jpg
> be?
Keep in mind that digital cameras work much differently than satellites like
IKONOS. A digital camera needs to be able to take a picture instantly with a
2D CCD array. Satellites like IKONOS have a 1D array of individual detectors
that sweep along the ground, taking a 2D image where one dimension represents
both a spatial dimension and time. In order to have anywhere near the
resolution of IKONOS in a digital camera, you would need thousands of times
as many detectors as IKONOS itself has, because you would need more than a 1D
array of sensors.
So don't expect digital cameras to be able to create pictures as large as
imaging satellites for quite a long time. :)
Erik Harris eharris1@rocheste$.$$.com
http://w3.to/erik ICQ: 2610172
Chinese Martial Arts Assoc @ Cornell: http://w3.to/CMAAC/
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