[meteorite-list] Iron Meteorite on Mars (Color Photo)

Gerald Flaherty grf2 at verizon.net
Thu Jan 20 17:26:46 EST 2005


The Other side says............."20th Century Fox..prop" made in China
Jerry
----- Original Message ----- 
From: "Sterling K. Webb" <kelly at bhil.com>
To: <cynapse at charter.net>; <meteorite-list at meteoritecentral.com>
Sent: Thursday, January 20, 2005 2:57 AM
Subject: Re: [meteorite-list] Iron Meteorite on Mars (Color Photo)


> Hi,
>
>    Assumption one is wrong.
>    Basically, the PanCam is just about as good a camera as the $19.95 
> Samsung Digital Point'N'Shoot
> dangling from the discount store rack. The image is 512x512 by 32 bits 
> deep (I presume) and that's your
> one megapixel.
>    If everyone chips in for the ticket, I'll borrow my neighbor's 7 
> megapixel Canon and go take some
> pictures of it. Heck, I'd even take a picture of the other side of the 
> rock. What does the other side
> look like anyway?
>
> Sterling K. Webb
> --------------------------------------------------
> Darren Garrison wrote:
>
>> On Wed, 19 Jan 2005 23:08:45 -0700, "Chris Peterson" 
>> <clp at alumni.caltech.edu> wrote:
>>
>> >Hi Darren-
>> >
>> >Replacing the Pancam sensor with, say, a 5MP array wouldn't yield better
>> >resolution. If the physical size of the sensor were larger, you would 
>> >have a
>> >greater field of view. But even if the sensor had smaller pixels, the
>> >resolution wouldn't increase because the simple, three element f/20 lens 
>> >of
>> >the camera has a spot size of 32um, twice the current pixel size. So 
>> >packing
>> >in more pixels would just be empty resolution- there would be no real
>> >increase in the amount of information available. A blown up image from 
>> >this
>> >5MP image would look the same as the image from the 1MP sensor after you
>> >resized it to 5MP.
>> >
>> >In this case, what we'd really like would be the ability of the Pancam 
>> >to
>> >switch in a longer focal length lens. Maybe the next mission!
>> >
>>
>> I must be misunderstanding something fundamentally here, then.  My 
>> assumptions are:
>>
>> 1.) the optics are precise enough to focus enough photons on the CCD to 
>> provide a sharp image to the
>> CCD cells at the higher pixel density
>>
>> 2.) the CCD cells are able to capture enough photons at the higher pixel 
>> density/smaller pixel size
>> to record a meaningful signal.
>>
>> Given those two assumptions (and neglecting for a moment that it may not 
>> fit the real-world
>> situation) how can putting a 5 million pixel CCD of the same size as the 
>> 1 million pixel CCD in the
>> place of the 1 million pixel CCD NOT collect five times as many points of 
>> information for the same
>> image focused on it?  Not talking about changing the focal length of the 
>> optics, just having a CCD
>> that can sample the same focused optical image in much smaller segments. 
>> Are you saying that this
>> would NOT give a better resolution, given the established meaning of 
>> "image resolution" as applies
>> to digital camera image output?
>>
>> If so, I don't understand how.
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>
>
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