That Truck Again

[P3D Jonathan Gross <catalyst@xxxxxxxxxxxx>]

Dave wrote:

> John Gross said:-
and
> That's not a very good comparison.  We are very intolerant of variations
> in spelling.  Well, mostly.
I usually go by Jon Gross or Jonathan Gross. I will tolerate John Gross,
but I do not identify with Joan Gross.

> That's why we use lossless compression on
> text files.  However, I defy you to spot the difference between #F0F0F0
> and #F0F0F1.  Especially if they are fluctuating at a high frequency
> between those values.  (For those not used to referring to colours as
> hexadecimal numbers that's grey and grey with a *very* faint touch of
> blue.)

What you say is true for monoscopic images.  The problem is that with
stereoscopic images pairs, the subtle high frequency variations in color
between the left and right fields may be all that defines horizontal
boundary differences (parallax) for a particular feature.  As has been
noted many times before on this list, the visual system is amazingly
sensitive to minute differences in images presented to the left and
right eyes. This discrimination is so acute in the horizontal direction
that you can throw away every other (vertical) raster of an image pair,
as long as you maintain the resolution in the horizontal axis.

I could not tell the difference in color caused by a single low order
bit on a single color used in your example.  However, lets make the
example more reasonable; lets use the two low order bits on each color
between two fields.  Assuming regression towards the dominant color in
the area in question, we now might loose as much as 3.1% (4/256*2) of
the detail which would have created stereoscopic parallax.

Jon


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