On Sun, 31 May 2009 23:44:15 -0800, (Floyd L.
Davidson) wrote:

Eric Stevens wrote:
You actually are that dense!

I read the words. I even quoted them down below. In fact, because you
have (surreptitiously) snipped an awful lot of what follows, its only
two paragraphs down.

You still think that I should quote your entire silly article.
That is *dense*.

Hell No! You should cut and paste my article to make it mean whatever
you would like it to mean. :-(

So what are you trying to say? The sensor locations *are*
relevant!

Only as part of the transformation algorithm.

No **** Sherlock. Which is to say, yes they are and
your statements otherwise were mistaken from the start.

You do understand that "firmware" is where the
"software" is, right?

I'm getting the idea that you have a list of buzz words; but no
idea what any of it means.

One of us doesn't seem to.

And it isn't at all difficult to determine which that
would be, Eric. Try, for example, to get a grip on
"interpolation" before you continue on with this
discussion. Try learning where software is used in the
data flow, and where it is a purely hardward process.

YOU try looking up interpolation in the context of the Bayer process.
I've done it once already for you. It didn't seem to ring a bell, even
the first time.

You made it false by chopping out the text around it which made clear
what I was talking about. For the benefit of others I had written:

"The sensor locations are irrelevant. The RAW data is derived
from the sensors by rules which are determined by the
manufacturer of the camera. The signals generated by the
sensors are determined by the rules inherent in the camera's
software. As I have already said, there is a one to one
correspondence between the source image and the RAW
file. You don't have a choice of RAW files for a given image.
Nor do you have a choice of images for a given RAW file".

Yes, and your statement is still false. Explaining a
false statement doesn't change the fact that it is
false.

False: "sensor locations are irrelevant"

False: "signals generated by the sensors are
determined by ... software"

False: "Nor do you have a choicce of images
for a given RAW file"

Look up Bayer interpolation.

Nice paragraph.

Regardless, you are still wrong. The signals from the
sensor are interpreted according to *hardware* and the
resulting data set is written to a RAW file format.
That is what is "interpreted" by software.

Have I ever said otherwise? But so what?

You did say otherwise. Quoted above.

I can't see where. Someone must have accidentally deleted it.

Now, if you missed where you'd said it before, take a look at
what you just repeated. See it now? It's wrong...

So you now admit that it is not software at all, but a
hard wired hardware transform.

I don't see why you should suddenly try to make that point. In any
case, while I don't know about your camera, I can download an update
for mine. That doesn't sound as though it is all hardware to me.

You aren't going to download an update that changes how the
hardware processes sensor data to generate the "raw data". It's
hard wired. The sensor output is *analog*, and the digital
data is generated by a series of *hardware* devices. About all
the software does is switch the hardware on and off!

First we are not talking about the RAW data. We (should) always have
been talking about the RAW data file.

The "RAW data file" is merely a file containing the
camera raw data. The only part of the file that relates
to the image is the data it contains. Which is to say
that we *are* talking about the "RAW data", even if you
want to call if a "RAW data file". It's the same data
either way.

Nope. What comes out of the sensor is not what is saved in the RAW
file. There is a transformation involved.

Note that "sensor data", in the context of this
discussion, would be the analog data directly read from
the sensor ....

.... what analog data?

...(though in other contexts those words might
be used to mean the digital data too).

I see you have had second thoughts.

"RAW data"
clearly must refer to the digital data that goes into
the "RAW file". That is the only place where "RAW" is
used. (And I often use "raw", simply because "RAW"
is grammatically incorrect. They are the same.)

Second, in the case of the Nikon
D300 the update has changed the way in which the raw data from the
sensors have been interpreted and saved to the RAW file.

Nice try, but I just read the release notes for Nikon's
upgraded firmware for the D300, and saw exactly *nothing*
like what you are saying.

Provide details, and be specific.

What do you make of:

. Image quality: NEF (RAW ) + JPEG
. NEF (RAW) recording: Lossless compressed or Compressed
. Image size: S or M

That sounds like a change in the way raw data from the sensors have
been interpreted and saved to the RAW file.

I wouldn't argue with you over what you have just said but I would
like to point out that this discussion has been about the interpolated
data saved in the RAW file.

The raw data saved in the RAW file is not interpolated.

See the last line of ...
http://en.wikipedia.org/wiki/Bayer_filter

"Bryce Bayer's patent called the green photosensors
luminance-sensitive elements and the red and blue ones
chrominance-sensitive elements. He used twice as many
green elements as red or blue to mimic the human eye's
greater resolving power with green light. These elements
are referred to as sensor elements, sensels, pixel sensors,
or simply pixels; sample values sensed by them, after
interpolation, become image pixels."

Didn't you read what that paragraph says????

Are you unable to determine that the "after
interpolation" is refering not to generation of data
that goes into the RAW file, but rather what is done
with data *from* the RAW file in order to make an image
(such as TIFF or JPEG). That is what "image pixels" means.

Haw! You really don't understand what Bayer interpolation is all
about.

The data saved in the RAW file has not yet been
interpolated, ....

How else do you reckon it is derived from the Bayer mosaic?

... and when it is interpolated it is *not*
saved in the RAW file, and is no longer considered "raw"
data.

Well, at least you understand that much.

The raw data does not define one specific image. When
the data is interpolated there is then an image!

And when that data is interpolated and saved in a RAW file then there

That does not happen. (Except of course for the various
thumbnail JPEG images that are embedded in most RAW files.)

Umm...

Ummmm..... see above.

is only the one image. Run that RAW file backwards through the same
transformation and you end back up with the original image of which
there can only be the one.

It is a one way process and it cannot be precisely
reversed. If for no other reason than what is called
quantization distortion...

Don't come the technical heavy with me! After all, you are the one who
claimed to not understand what I meant by "statistical error
limitations".

I know exactly what *you* meant by that. The point was
that your statement was wrong, and you threw in
nonsensical statement to make it appear to have
significance. Statistical error limitations indeed!

My oath there are statistical error limitations! That you call it
'quantization distortion' doesn't change the fact.

However, in addition to that
the JPEG image which results from interpolation simply
does not contain anything like the full amount of
information that was in the RAW file's data. You cannot
reverse the process.

HOW DO I MAKE IT CLEAR THAT FROM THE BEGINNING WE HAVE BEEN TALKING
ABOUT THE RELATIONSHIP BETWEEN THE ORIGINAL IMAGE ON THE SENSOR AND
THE 'RAW' FILE.

Then don't talk about interpolation and other software processing
of the raw data, all of which takes place on data *after* it is
placed in the RAW file.

Dingbat - interpolation is an assential part of going from the Bayer
array to the RAW data file. Please don't continue to pretend
otherwise.

Sorry for shouting but I've said the above several times,

And then you talk about something different. You don't
seem to have even a meager knowledge of the data flow.

I've quoted
from the original articls, and you still keep trying to switch to
conversion from RAW to JPG. That's an entirely different question.

Then stop talking about processing the RAW data to make an image.

I haven't been. If anything I've been talking about working backwards
from the RAW data file to reconstruct the original image.



Eric Stevens