Hi all,

I want to analyze a series of digital photos to see what colors appear
most frequently. Assume all photos are in 24 bit RGB. Do you have any
idea how to do it? Just generate a 255 x255 x255 table, each entry of
which contrains the number of times that color appears?

I think that this analysis is very common and useful. I guess someone
should have done it before. I don't find any information about this
in literature, though. Do you know if there is another method better
than the 3-D table above? and it would be great if we can visualize as
the case of 2-D histogram.

And do you know if there is any paper which discuss what colors are
the most common?

Thank you.

Dear all,

I need the following paper:

Manuel Melgosa, Rafael Huertas, and Roy S. Berns, "Performance of
recent advanced color-difference formulas using the standardized
residual sum of squares index",
In: JOSA A, Vol. 25, Issue 7, pp. 1828-1834, 2008
or: JOSAA 24, 1823-1829, 2007

Is there any one who can send me this article please?

Lots of thanks,
Saeideh

Hi folks,

one of the things that makes we always wonder is how the normalization
from "absolute" color coordinates XYZ to "relative" or "normalized"
coordinates xyz is done. One can of course simply accept the definition,
namely

x = X / (X + Y + Z) etc

but why is it done this way? First of all, if Y is the luminance (and
that's as far as I know how the Y channel is defined, approximately),
then why hasn't x been defined as "luma normalized" coordinate, namely

x = X / Y etc.

which, clearly, would set y = 1 (relative luminance = identity).

On a related thought, why does one divide by the *sum* of the three
coordinates. If I would consider XYZ as a vector in R^2, then wouldn't
it be "more natural" to divide by its length, i.e.

x = X / sqrt(X^2 + Y^2 + Z^2) etc.

I understand the way things are done, and I'm ready to accept "this is
only a definition", but is there a specific reason behind the way it was
done? I find that the two approaches above (either of them) seem to be
more natural than the one taken by the CIE, so what's the rationale here?

I have been writing a software for QC purpose of Color differences.
But I am not sure my results are correct or not. So, can you please
advice me very simple software which I can enter reflectance values
(40 pcs 360-750 nm) and it will give me L,a,b,C,H and DELTA C, DELTA
H, DELTA E in different color spaces (like cie, cmc etc)? This will
help me to check my calculations are true or not.

Thanks to all in advance.

Hakan

Here's something I learned about (from Vision System Design, an
industry magazine) that may interest people. Jack Ladson is (or was)
the chairman of the ASTM Committee on Color and Appearance. He's
giving an introductory webcast on color imaging.
-------------------------------------------------------------------------------------------------------------------------

An Interactive, Online Webcast
July 22, 2008 | 10:00AM PDT | 1:00PM EDT | 17:00 GMT

Color imaging is a fast-growing and used frequently technology in
machine-vision applications. While many engineers are familiar with
RGB cameras, very few have explored the different color spaces that
can be used to analyze, interpret, and understand color information.
By transforming RGB color images into different color spaces,
different aspects of an image can be understood. For example, one of
the most commonly used transforms - the HIS transform -- separates
hue, intensity, and saturation components making it easier for image
processing software to interpret the data collected.

Hello,

The woman that was resqued from the farc/colombian jungle was broadcasted by
different television channels.

Among france channel, euro channel, and cnn channel.

However the colors on france and euro channel looked very alive and
colorfull... while the cnn colors looked very dull, mate, gray and vague...
for example people had green or blue suit on euro channel and it looked near
dark/black on cnn channel, other example... dude had like almost pink/beige
suit... but it looked vage on cnn channel... like some cheap old suit from
the past ;)

It's was exactly the same video but still different colors ?

What causes these different colors ?

My best guess is:

1. CNN compresses the video signal to broadcast it via satelites or so to
save money...

2. Or they simply have old/bad equipment ?

3. Or bad settings ???

Dismissed:

Hi all,

I need to calibrate my PR-705. Is there anybody knowing how to do it?
Or I need to send it to the manufacturer?

Thanks

In touristic books and on postcards the sky is often
too blue and too dark, IMHO.

1. Which color (Lab) has a nice blue sky at noon ?

2. Which color (Lab) should this sky have in an image ?
My suggestion: 65 / -5 / -40 or so.
This is a kind of cyanish-blue.

Best regards --Gernot Hoffmann

I'm pleased to announce the release of V1.0.0 of ArgyllCMS.

Apart from numerous bug fixes and many minor feature additions and improvements, the main changes
to this version compared to the V0.70 Beta 8 are:

* Speedup in profile and device link generation (inversion code), and better memory usage.
* Support for embedded profiles in TIFF files.
* Support for installing and uninstalling and loading...

Hi all.

From the Adobe site

http://www.adobe.com/cfusion/exchange/index.cfm?event=extensionDetail&loc=en_us&extid...

you can download a small freeware application, based on Adobe AIR, I
wrote (in Adobe Flex).

It is the 1.0 version of a color CIELAB difference calculator that
computes various deltaE metrics.

Please contact me if you are interested in contributing or testing.

Thanks in advance.

Mauro Boscarol