Matlab中的3D眼图

Question

Hello every one i have been working on an eye 3D model in mat lab and all i have come up with is a flattened sphere, what should i add to it to make a realistic eye model?

[x,y,z] = sphere();
r = 5;
surf( r*x, r*y, r*z+2, 'edgecolor', 'none' )
axis equal, grid off, axis off

hold on
[x,y,z] = sphere;      
x = x(15:end,:);       
y = y(15:end,:);       
z = z(15:end,:);      
rx = 4;ry = 4;rz = 8;  
surf(rx*x,ry*y,rz*z);  
axis equal;  

set(gcf, 'Renderer', 'OpenGL');
shading interp, material shiny, lighting phong, lightangle(0, 55)

This is the code of what I have tried but still not close to what I expect

Answer 1

Your question is not well defined at all. For example what is not good with your output ?

• The shape of the eye ?
• The final rendering (color, light etc ...) ?

And I'm not even asking your definition of the desired 3D model. Between a full 3D model where you can cut cross sections and a 3D outside surface surface suitable for 3D visualization, I guess you are talking about the later (the approach would be completely different for the first option).

Regarding the final output rendering, I can give a few pointers on how to use texture mapping ... very useful feature for these kind of project.

Simple texture mapping with the first textures I could find on google can give you this kind of result:

Here's the code (note that I define my spheres slightly differently than you but that's just a personal choice) :

%% // generate unit sphere and prepare figure
[x,y,z] = sphere();
hf=figure('Color','w') ;
axis equal, grid off , axis off , hold on

%% // Define the main globe coordinate and generate surface
rMain = 5;
xm = x*rMain ;
ym = y*rMain ;
zm = z*rMain ;
mainGlobe =  surf( xm, ym, zm, 'edgecolor', 'none' ,'FaceAlpha',0.5 ) ;

%% // Define the Iris sphere and generate surface
rIris = 2.5 ;
cutoff = ceil(size(x,1)/2) ; %// calculated to get a half sphere (better result for later texture mapping)
xi = x(:,cutoff:end) * rIris ;       
yi = y(:,cutoff:end) * rIris /3 + (rMain-rIris)*1.7 ;       
zi = z(:,cutoff:end) * rIris  ;
irisGlobe = surf( xi, yi, zi , 'edgecolor', 'none'); 

Notice that for the Iris, i start with a half sphere, which I then compress in the Y direction (and translate to position it on the outside surface of the main globe). This produce better rendering of the texture mapping.

You've got two surface, now applying texture mapping can be anything from very straightforward (I'll give a simple example) to quite tedious ... depending on the desired result and the images you have to work with.

For the first example I'll use 2 images, one for the eye globe and one for the Iris. The images will be available at the end of the post.

%% Apply texture mappings
imgIris = imread('Iris03.jpg') ;   %// read Iris texture image
imgGlobe = imread('globe02.jpg') ; %// read Globe texture image

%// (optional) mirror globe image to repeat pattern (and increase definition)
CDglobe = [imgGlobe flipdim(imgGlobe,2)] ;

%// apply mapping
set(mainGlobe,'FaceColor','Texturemap','Cdata',CDglobe,'FaceAlpha',0.5)
set(irisGlobe,'FaceColor','Texturemap','Cdata',imgIris,'edgecolor', 'none')

%// texture mapping in default direction produce blood vessel in `Z`
%// direction mainly, so to have them departing from the Iris, we just
%// rotate the main globe by 90 degree (or we could also rotate the
%// image beforehand ...)
rotate(mainGlobe,[1 0 0],-90)

With the same shapes (surfaces) but different textures, you can get quite visually different results. For example:

imgIris = imread('Iris01.jpg') ;   %// read Iris texture image
imgGlobe = imread('globe01.jpg') ; %// read Globe texture image

%// mirror globe image to repeat pattern (and increase definition)
nrep = 3 ;
CDglobe = repmat( [imgGlobe flipdim(imgGlobe,2)], [1 nrep 1]) ;

%// apply mapping
set(mainGlobe,'FaceColor','Texturemap','Cdata',CDglobe,'FaceAlpha',0.5)
set(irisGlobe,'FaceColor','Texturemap','Cdata',imgIris,'edgecolor', 'none')

will get you the second set of eye example above. Notice how I replicated the texture data before applying them, it allows to repeat the pattern around the eye instead of having it only once. You can play with the nrep repetition factor for varying results.

---

If you want a more protuberant Iris, you can use a variation of the line where yi is defined (that's where the sphere is compressed and offseted). For example, with another texture and this line :

yi = y(:,cutoff:end) * rIris  + (rMain-rIris)*1.7 - 1.1 ;

The resulting Iris is slightly more prominent:

---

The images used for texture are given here. There are a gazillion images available on internet which will give even better result. Whether it's synthetic images (pure computer graphics) or real eye/iris pictures, just pay attention that many images may have a copyright which you will have to respect ...

• Globe01
• Globe02
• Iris01
• Iris02
• Iris04

Answer 2

Do you want something like this?

[x, y, z] = sphere();
r = 5;
eballcolor = ones([size(x) 3]);
surf(r*x, r*y, r*z+2, eballcolor, 'edgecolor', 'none');
hold on;
[x, y, z] = sphere();
x = x(15:end,:);
y = y(15:end,:);
z = z(15:end,:);
rx = 4; ry = 4; rz = 8;
corneacolor = zeros([size(x) 3]);
surf(rx*x, ry*y, rz*z, corneacolor);
grid off
axis off
axis equal;
axis vis3d;

set(gcf, 'Renderer', 'OpenGL');
shading interp, material shiny, lighting phong, lightangle(0, 55);