Path: utzoo!attcan!uunet!mcvax!ukc!reading!onion!reading!onion!henry!jadwa
From: jadwa@henry.cs.reading.ac.uk (James Anderson)
Newsgroups: comp.graphics
Subject: Perceived size
Message-ID: <930@onion.cs.reading.ac.uk>
Date: 29 Jun 88 11:34:32 GMT
Sender: news@onion.cs.reading.ac.uk
Reply-To: jadwa@henry.cs.reading.ac.uk (James Anderson)
Distribution: comp
Organization: Comp. Sci. Dept., Reading Univ., UK.
Lines: 18


In <350001@hpcvlx.HP.COM> ben@hpcvlx.HP.COM (Benjamin Ellsworth) writes:

> A disc 3" in diameter at 10ft has the same perceived size as a
> disc of what diameter at 100ft?

Perspective projection provides an obvious, but almost always
wrong answer about PERCEPTION. People, and many terrestrial
animals, re-scale objects so that they approach a canonical
size. Its called, "size constancy". It is terribly complicated,
utterly un-programable, and leeds to lots of interesting
discussion in psychology text books and common rooms!

Sadly, I don't think you wanted to know that...

James

(JANET) James.Anderson@reading.ac.uk