[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
RE: Puzzle Solution and Compression
- To: email@example.com
- Subject: RE: Puzzle Solution and Compression
- From: firstname.lastname@example.org
- Date: Wed, 21 Oct 1998 14:32:53 -0400
- Old-Return-Path: <email@example.com>
- Resent-Date: Wed, 21 Oct 1998 14:57:08 -0400
- Resent-From: firstname.lastname@example.org
- Resent-Message-ID: <"4cC0yC.A.ZS.a4iL2"@kani.wwa.com>
- Resent-Sender: email@example.com
Tom et al.,
A co-worker of mine actually got interested in compressing Mark III images
using a scheme similar to what Herb suggested. By dropping the lower 4 bits
and using differences between pixel values he was able to get compression
ratios of about 3.5 to 1. Dropping the lower 4 bits made no difference to
the Star program's results since the noise was on the order of 6 bits anyway
in my light polluted skies. A similar approach might be usable for the Mark
Note that using only the upper 12 bits would still give us a dynamic range
of 4096 to 1.
From: Tom Droege [mailto:firstname.lastname@example.org]
Sent: Wednesday, October 21, 1998 1:57 PM
To: email@example.com; firstname.lastname@example.org
Subject: Re: Puzzle Solution
I hope to get to 10,000 to one. This is what Lockheed
claims is possible,
and I hope to get there. This does not leave much room for
Only a few percent will be possible, I think.
At 12:49 PM 10/21/98 -0400, you wrote:
>On Tue, 20 Oct 1998 12:04:26 -0500, Tom Droege
>*>I would like to congratulate Andrew Bennett for correctly
>*>puzzle. Below is his complete solution:
>*>>It looks a lot like you are getting the wrong high order
>*>>byte - either the one before or the one after.
>*>>Andrew Bennett, Avondale Vineyard, Nova Scotia, Canada.
>Facinating! I was suspecious of a byte order problem: it
>occur to me casually it was a "byte sequence" problem.
>Tom, as you are looking at all the bits, let us know when
>a measure for the reliable dynamic range of the new design.
>talked about data compression recently, and a simple
>scheme would be to remove the lowest and presumably
>And of course it affects small difference measurements and
>Herbert R. Johnson
>email@example.com voice 609-771-1503, New
> amateur astronomer and astro-tour guide
> classic S-100 computers restoration & parts as "Dr.
> rebuilder/reseller of classic Macs for your computing
> and senior engineer at Astro Imaging Systems