496 |
Color is the most dominant visual attribute of a texture. |
Color is the most dominant visual attribute of a texture. |
497 |
Therefore, it is essential that the overall colors of the |
Therefore, it is essential that the overall colors of the |
498 |
backgrounds are maximally diverse with respect to color perception. |
backgrounds are maximally diverse with respect to color perception. |
|
|
|
499 |
However, we come again to the entropy arguments |
However, we come again to the entropy arguments |
500 |
in Section~\ref{secfeaturevec}: |
in Section~\ref{secfeaturevec}: |
501 |
too many different colors in one background are perceived just |
too many different colors in one background are perceived just |
502 |
as a mix of many colors, making all such backgrounds look the same. |
as a mix of many colors, making all such backgrounds look the same. |
503 |
The backgrounds of random texels discussed earlier are an |
The backgrounds of random texels discussed earlier are an |
504 |
extreme example of this. |
extreme example of this. |
505 |
|
To maintain color balance, |
506 |
|
we use a small palette of colors for each background, |
507 |
|
chosen by heuristic perceptual methods. |
508 |
|
|
509 |
%In addition to choosing perceptually diverse colors, |
%In addition to choosing perceptually diverse colors, |
510 |
%there is the the question of how many colors to use. |
%there is the the question of how many colors to use. |
512 |
% Using multiple different colors in a background allows |
% Using multiple different colors in a background allows |
513 |
% a multitude of different combinations |
% a multitude of different combinations |
514 |
|
|
|
To maintain color balance, |
|
|
we use a small palette |
|
|
of carefully chosen colors for each background, |
|
|
|
|
515 |
% independent of the basis textures producing |
% independent of the basis textures producing |
516 |
% the shapes of the background. |
% the shapes of the background. |
517 |
% Register combiners are used to combine the shape with the colors |
% Register combiners are used to combine the shape with the colors |
536 |
% 2) not really uniform; it's MORE uniform than RGB but not |
% 2) not really uniform; it's MORE uniform than RGB but not |
537 |
% absolutely uniform |
% absolutely uniform |
538 |
|
|
539 |
To address readability, we only use colors with the CIE $L^*$ |
For readability, we only use colors with the CIE $L^*$ |
540 |
lightness value over 80 (percent of maximum). |
lightness value over 80 (percent of maximum). |
541 |
% Mention screen gamma earlier, maybe here. |
Note that for correct computation of the lightness, |
|
For correct computation of the lightness, |
|
542 |
it is essential that the display gamma is properly adjusted |
it is essential that the display gamma is properly adjusted |
543 |
for linear RGB reproduction. |
for linear RGB reproduction. |
|
% Onko lineaarinen *varmasti* oikea LAB-muunnokselle? |
|
544 |
|
|
545 |
Because the shapes should also be distinguishable, |
For each background, |
546 |
we use one half dark colors and one half light colors in the |
we use colors from {\em both} the dark and light end of the |
547 |
range to have some contrast for the shapes. |
80-100 range in order to create some contrast. |
548 |
This avoids the unpleasant, blurry appearance of backgrounds with only |
This makes the shapes in the texture distinguishable, |
549 |
|
and avoids the unpleasant, blurry appearance of backgrounds with only |
550 |
chroma changes in colors. |
chroma changes in colors. |
551 |
%Having contrast makes shapes distinguishable |
%Having contrast makes shapes distinguishable |
552 |
|
|
557 |
%% Doesn't really need to be said here; it's what people |
%% Doesn't really need to be said here; it's what people |
558 |
%% will naturally assume. |
%% will naturally assume. |
559 |
|
|
560 |
To produce compatible colors, we choose the hue angles from a distribution |
To produce compatible colors, we choose |
561 |
% To have: huonoa englantia |
the hue angles from a distribution |
562 |
concentrated on one random hue with a random variance and |
concentrated on one random hue with a random variance and |
563 |
saturations from an ad hoc distribution. |
saturations from an ad hoc distribution. |
564 |
This produces related colors with high probability, but still |
This produces related colors with high probability, but still |
790 |
\label{fig-identity-via-textures} |
\label{fig-identity-via-textures} |
791 |
a) different documents with similar appearance and a focus+context view |
a) different documents with similar appearance and a focus+context view |
792 |
showing relations, |
showing relations, |
793 |
b) the same documents and the same view with identity visualized with unique backgrounds |
b) the same documents and the same view with identity visualized with unique backgrounds. If viewing this document on a screen, make sure the your gamma is properly set; the text {\bf is} readable if the gamma is correct but the textures are too dark if not. |
794 |
} |
} |
795 |
\end{figure*} |
\end{figure*} |
796 |
|
|