Archived posting to the Leica Users Group, 1999/10/13

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Subject: Re: [Leica] do your homework, please!
From: "Anthony Atkielski" <anthony@atkielski.com>
Date: Thu, 14 Oct 1999 00:04:34 +0200

From: Erwin Puts <imxputs@knoware.nl>
Sent: Wednesday, October 13, 1999 20:15
Subject: [Leica] do your homework, please!


> Below the real figures. 5 microns equals
> 5/1000 mm and thus equals 200 lines/mm or
> 100lp/mm 250lp/mm equals 500 lines/mm equals
> 2/1000 mm.

Agreed.  My mistake.

> This statement is false too:
> "Digital means a symbolic representation,
> period."

No, that statement is true.

> In fact "Digital" means using only the digits 0
> and 1 ...

No, digital applies to any type of symbolic representation.

The first digital computers used base 10.

> A symbolic representation refers to anything that
> can carry a meaning and acts as a proxy to that meaning.

Yeah... a digital representation.

> The current French philosophers are masters in the
> art of naive nonsensical discourse based on hardly
> or falsely understood modern science.

I'll take your word for it.  How is that germane here?

> The human eye uses cones and rods, and the less numerous cones are
> responsible for color vision.

Yes.  Just like a mosaic filter over a CCD.  And the cones sensitive to green
light are much more numerous than those sensitive to red and blue light--which
is why CCDs have more green-filtered cells than red- or blue-filtered cells.
The whole idea, after all, is to produce images suitable for human viewing.

> The tri-stimulus mechanism has a very superficial
> resemblance to the CCD mechanism in the popular digital
> camera ...

The resemblance to a CCD is far greater than the resemblance to film.

> Any CCD sensor signal can be recorded as an analogue signal,
> no need for a digital capture here. So digital and analogue can be
> mixed as it is in the eye.

Digital and analog are always mixed.  The advantages of digital apply only in
the digital realm, however.

  -- Anthony