Bytes in a pixel?

[Guest]

Archived from groups: rec.photo.digital (More info?)

On 15 Dec 2004 20:45:00 +0800, Bruce Murphy <pack-news@rattus.net>
wrote:

>imbsysop <imbsysop@yahoo.com> writes:
>
>> On 15 Dec 2004 19:54:15 +0800, Bruce Murphy <pack-news@rattus.net>
>> wrote:
>>
>> >"Ryadia" <ryadia@hotmail.com> writes:
>> >
>> >> Perhaps Bruce, you could enlighten us as to the definition?
>> >
>> >A discrete element of a planar space, usually rectangular. This isn't
>> >complicated.
>>
>> you mean that's the definition of a sensel on a sensor ?
>
>No, I don't. A pixel is an abstract concept for which there are many
>physical realisations with varying levels of divergence from this
>original definition..

so why not stay with the original definition ? It is simple enough
to cover the general idea of being a picture element .. (and hence
have no dimension causing the eternal confusion between the pixel
itself and its representation on any "picturing" device)
Now it has been smeared out from being a sensor (sensel) in a Bayer
pattern CCD up to "I_don't_know_what" ... obscuring all & everything
...
FWIW

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

Bruce Murphy <pack-news@rattus.net> writes:

>one? one and a half? two? three? four and a half? six? eight? This is
>where things start getting very complicated. Are you chasing a real
>explanation or a 'lies to children' type glib one?

Don't forget 1/2, 1/4, and 1/8 byte per pixel. One bit per pixel is
used for bitonal images (typically scanned text, or very high resolution
typeset characters). 2 bits per pixel gets 4 colours, used in some map
displays. 4 bits per pixel is 16 colours, used in some older computers
and some other maps.

Dave

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

imbsysop <imbsysop@yahoo.com> writes:

> On 15 Dec 2004 20:45:00 +0800, Bruce Murphy <pack-news@rattus.net>
> wrote:
>
> >imbsysop <imbsysop@yahoo.com> writes:
> >
> >> On 15 Dec 2004 19:54:15 +0800, Bruce Murphy <pack-news@rattus.net>
> >> wrote:
> >>
> >> >"Ryadia" <ryadia@hotmail.com> writes:
> >> >
> >> >> Perhaps Bruce, you could enlighten us as to the definition?
> >> >
> >> >A discrete element of a planar space, usually rectangular. This isn't
> >> >complicated.
> >>
> >> you mean that's the definition of a sensel on a sensor ?
> >
> >No, I don't. A pixel is an abstract concept for which there are many
> >physical realisations with varying levels of divergence from this
> >original definition..
>
> so why not stay with the original definition ?

Because the 'original' definition is not only fairly naive, but has
also become corrupted by decades of near-enough approximations.

Nothing I've said above makes them any more useful.

> It is simple enough
> to cover the general idea of being a picture element ..

But you need the word discrete there. You also need to point out that it
is planar, not volumetric.

> (and hence
> have no dimension

And where did 'have no dimension' come from? Why should a pixel not
have an extent, and thus dimensions?

> causing the eternal confusion between the pixel
> itself and its representation on any "picturing" device)

This 'eternal confusion' is really just stupidity on the part of
people frightened of simple multiplicative relationships.

> Now it has been smeared out from being a sensor (sensel) in a Bayer
> pattern CCD up to "I_don't_know_what" ... obscuring all & everything

sensor elements, particularly ones in a Bayer map sensor don't map
directly to pixels in the final image, which is presumably why this
other ridiculous term emerged. In a monochrome sensor, or in something
like a foveon, they do map directly.

B>

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

davem@cs.ubc.ca (Dave Martindale) writes:

> Bruce Murphy <pack-news@rattus.net> writes:
>
> >one? one and a half? two? three? four and a half? six? eight? This is
> >where things start getting very complicated. Are you chasing a real
> >explanation or a 'lies to children' type glib one?
>
> Don't forget 1/2, 1/4, and 1/8 byte per pixel. One bit per pixel is
> used for bitonal images (typically scanned text, or very high resolution
> typeset characters). 2 bits per pixel gets 4 colours, used in some map
> displays. 4 bits per pixel is 16 colours, used in some older computers
> and some other maps.

I realise this, but point out that they're all quite rarely used in
the photographic context of this newsgroup!

B>

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

"Paul H." <xxpaulhtck@zzcomcast.yycom> writes:

> Here's a simple definition: a pixel is an ordered

Wrong

> 3-tuple

Wrong

> in a three-dimensional

Wrong

> color

Wrong

> space having equal

Wrong

> bit resolution along each orthogonal

Wrong

> color axis.

Well, you did say `simple'.

--
Paul Repacholi 1 Crescent Rd.,
+61 (08) 9257-1001 Kalamunda.
West Australia 6076
comp.os.vms,- The Older, Grumpier Slashdot
Raw, Cooked or Well-done, it's all half baked.
EPIC, The Architecture of the future, always has been, always will be.

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

<prep@prep.synonet.com> wrote in message
news:87llbys4o2.fsf@prep.synonet.com...
> "Paul H." <xxpaulhtck@zzcomcast.yycom> writes:
>
> > Here's a simple definition: a pixel is an ordered
>
> Wrong
>
> > 3-tuple
>
> Wrong
>
> > in a three-dimensional
>
> Wrong
>
> > color
>
> Wrong
>
> > space having equal
>
> Wrong
>
> > bit resolution along each orthogonal
>
> Wrong
>
> > color axis.
>
> Well, you did say `simple'.
>
> --
> Paul Repacholi 1 Crescent Rd.,
> +61 (08) 9257-1001 Kalamunda.
> West Australia 6076

My post was OBVIOUSLY intended as a satirical comment about the incessant
quibbling over trivialities daily conducted in this newsgroup by
anal-retentive obfuscators and savant-wannabees.

BZZZT... Thanks for playing!

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

"Paul H." <xxpaulhtck@zzcomcast.yycom> writes:

> My post was OBVIOUSLY intended as a satirical comment about the incessant
> quibbling over trivialities daily conducted in this newsgroup by
> anal-retentive obfuscators and savant-wannabees.

And yet completely indistiguishable from a buzzword-laden response by
someone who didn't understand what they were talking about.

Strange.

B>

 

[Guest]

Archived from groups: rec.photo.digital (More info?)

"Paul H." <xxpaulhtck@zzcomcast.yycom> writes:

> So much for civility. I suggest you apply your arrogance somewhere else and
> your repeated quibbling proves my original point.

Whatever the hell your original point was.

> Concerning your remark about the unit step function: the term "pixel" is
> jargon, a technical word invented to provide a convenient shorthand
> decriptor

Yes? This is what words do. That they are placeholders for more
complex concepts does not excuse them from requiring definitions.

> --it is not a quantity requiring a formal mathematical derivation.

Mathematial derivation and a precise definition are two very different
things. The word 'quantity' is misapplied here.

> Until step functions are indeed useful and I suspect you haven't a clue
> about when and how they are used.

"So much for civility". "I suggest you apply your arrogance somewhere
else" and your repeated misuse of simple words illustrates your
inability to grasp these concepts.

If you have an issue with the definition for pixel I proffered, then
*say* so, don't beat about the bush.

B>