Color Visualization in Matlab

Monday, 11/18/2002

Announcement: We do not have class in Wednesday (11/20) .You will work on the project III and bring questions to Friday’s class.In Friday’s class, we will schedule your presentation for choices either Monday (11/25) or Wednesday (11/27).

Visualization of FEM Results

Displacementfield

Pixel:The smallest image-forming unit of a video display.

Create a Figure Windowfigure(‘Position’,[left,bottom,width,height])

Example

Additive Color

€

color=w1*Red+w2*Green+w3* Blue

RGB Color Model

[0,1,1]

[red,green,blue]

[0,1,0]

[1,1,1]

[0,0,1]

[1,0,1][1,0,0]

[1,1,0]

Color Cube

Example

ny=60;nx=20;figure ('Position', [100, 100, ny, nx*3]);colormap([1 0 0; 0 1 0; 0 0 1])

imageMatrix = [ones(nx,ny) ones(nx,ny)*2 ones(nx,ny)*3];

image(imageMatrix)axis equal off

nx

ny

Hue-Saturation-Value colormap

HSV is used in conjunction with colormap to specify a colormap which varies the hue component of the hue-saturation-value color model.

The colors begin with red, pass through yellow, green, cyan, blue, magenta, and return to red. The map is particularly appropriate for displaying periodic functions.

HSV Color Example

figure ('Position', [100, 100, 256, 50]);colormap(hsv(256));

imageMatrix = zeros(50,256);for ix=1:50 for iy=1:256 imageMatrix(ix,iy) = iy; endend

image(imageMatrix)axis equal off

Understanding Colormaps

Color Assignment

Mapping Rule

Visualization of FEM Results