f*******d
发帖数: 339 | 1 just run into an interesting problem, want to share with with you:
the color on computer screen is represented by three numbers, red , green,
blue. These all ranges from 0 to 255 for their brightness.
Now suppose we want to generate a number of points with equal brightness,
which means
r+g+b=const. For example, if we want three points, and the total brightness
255, we could
simply set it to be (0 0 255), (0, 255, 0), (255, 0, 0). We shall call each of
these
point a (secondary) color (In this sp | N*********r
发帖数: 40 | 2 It solely depends on your distance measurement. If your measurement is
in a simple analytical form, e.g. Cartesian or Manhattan distance,
it's a well-defined (possibly non-linear) optimization problem, although the
solution may be non-trivial.
There are probably piles of papers discussing distance or distintiveness
of colors from human eye's prospective... I would say you could form a
reasonable distance measurement function candidate from any one of them :)
【在 f*******d 的大作中提到】
: just run into an interesting problem, want to share with with you:
: the color on computer screen is represented by three numbers, red , green,
: blue. These all ranges from 0 to 255 for their brightness.
: Now suppose we want to generate a number of points with equal brightness,
: which means
: r+g+b=const. For example, if we want three points, and the total brightness
: 255, we could
: simply set it to be (0 0 255), (0, 255, 0), (255, 0, 0). We shall call each of
: these
: point a (secondary) color (In this sp
| N*********r
发帖数: 40 | 3 First of all, the brightness of a RGB pixel is not simply R+G+B.
( I use capital RGB because they are not normalized )
take YUV for example, Y = 0.299R + 0.587G + 0.114B
Anyway, let's define "brightness" as R+G+B, but the polygon described by
0 <= R <= 255
0 <= B <= 255
0 <= G <= 255
on the plane
R+G+B = c
where c is a constant, is not nessarily a triangle at all. An obvious
(counter) example is c = 3/2 * 255
【在 f*******d 的大作中提到】
: just run into an interesting problem, want to share with with you:
: the color on computer screen is represented by three numbers, red , green,
: blue. These all ranges from 0 to 255 for their brightness.
: Now suppose we want to generate a number of points with equal brightness,
: which means
: r+g+b=const. For example, if we want three points, and the total brightness
: 255, we could
: simply set it to be (0 0 255), (0, 255, 0), (255, 0, 0). We shall call each of
: these
: point a (secondary) color (In this sp
| s***l
发帖数: 2236 | 4 sorry I reconsider your question and it actually turns out that
I am not sure about your definition of brightness. But my previous
explaination is the definition of saturation actually.
normally color is defined by Hue, Saturation and Brightness.
and brightness does have different definitions since it is more a
human viewing value.
Several means of describing it are:
"Intensity": Found by mechanical measurement of the "power" of the
light.
"Brightness"(HSB): For a color to emit more or less ligh
【在 f*******d 的大作中提到】
: just run into an interesting problem, want to share with with you:
: the color on computer screen is represented by three numbers, red , green,
: blue. These all ranges from 0 to 255 for their brightness.
: Now suppose we want to generate a number of points with equal brightness,
: which means
: r+g+b=const. For example, if we want three points, and the total brightness
: 255, we could
: simply set it to be (0 0 255), (0, 255, 0), (255, 0, 0). We shall call each of
: these
: point a (secondary) color (In this sp
| f*******d
发帖数: 339 | 5 r+g+b, if I understand correctly, is very close to what you call intensity, although in a more careful definition it might be weighted sum.
The Hue, Saturation, Brightness system is somewhat different from what I am
describing(rgb). The saturation, if I remember correctly, is basically a kind of ratio
of colorness and whiteness. However, the colorness there is given in terms of
a relative fraction, whereas the r,g,b numbers given above are absolute.
【在 s***l 的大作中提到】
: sorry I reconsider your question and it actually turns out that
: I am not sure about your definition of brightness. But my previous
: explaination is the definition of saturation actually.
: normally color is defined by Hue, Saturation and Brightness.
: and brightness does have different definitions since it is more a
: human viewing value.
: Several means of describing it are:
: "Intensity": Found by mechanical measurement of the "power" of the
: light.
: "Brightness"(HSB): For a color to emit more or less ligh
|
|
