Prev: Code for image segmentation using water reservior technique
Next: code for image segmentation
From: Walter Roberson on 25 Jan 2010 18:17
striker wrote:
> Walter Roberson <roberson(a)hushmail.com> wrote in message
> <hjksmp$lde$1(a)canopus.cc.umanitoba.ca>...
>> striker wrote:
>> > I want to create a 3D model of banana in matlab.how is it possible.

>> Sorry, Matlab is equipped with built-in self-defences against
>> modelling fresh fruit.

> sorry i couldnot get ur point

*Sigh* Have you ever considered the possibility of telling us what you
are actually trying to accomplish??


Which varietal of the over 200 kinds of bananas are you trying to model?

How many sides does the banana have? (Note: I have one here at home that
has one more side than the answer you'll find searching Google, so
you'll need to cross-check with actual examples of the varietal.)

Are the sides flat? Are they equal area? What is the cross-sectional
curvature of each? How does that curvature change along the length?

Are you able to create an adequate approximation of the colours
(including the specular reflectivity) using RGB or HSV? For example, the
image here shows a good range of colours, but it also indirectly
illustrates the point that common image formats are poor at capturing
the specular information -- a point that will be important if you are
trying to create realistic CGI models for use in (say) a movie.
http://upload.wikimedia.org/wikipedia/commons/a/a1/RedBananasMetepec.JPG

What is the internal structure of the banana? How ripe is the banana?
How does the internal structure change with the ripeness? How do the
tensile, compressive, and shear stresses vary with the ripeness? I
understand that in some of the varieties of bananas, the phloem bundles
can be quite strong under tensile stress. The length and arrangement of
the fibres will be important if your purpose is to do a finite element
mesh examination of deformation of bananas under stress.

What is the chemical composition of the banana? How does that chemistry
change with heat? Does the rate of heating matter for this purpose? It
makes a difference if your purpose is to model the internal change of
bananas as they are roasted, or as they are prepared in lye for fibre
extraction.

And, as John mentioned, you may need additional toolkits if your purpose
is to model the use of bananas as attack weapons.
From: striker on 26 Jan 2010 07:22
I just want to create a model which looks like a banana.so that i can rotate it along any axis and i can scale it in any direction.
From: ImageAnalyst on 26 Jan 2010 08:19
On Jan 26, 7:22 am, "striker " <friend_...(a)hotmail.com> wrote:
> I just want to create a model which looks like a banana.so that i can rotate it along any axis and i can scale it in any direction.

----------------------------------------------------------------------------------------------------------------------------
Is it so important that it be a banana, specifically? Why can't you
do your little practice with, say, a klein bottle, for which MATLAB
already has a demo (see help on the xpklein function)

Simply type "xpklein" in the command window, or run the source code
for it (from the Help documentation):

n = 12;
a = .2; % the diameter of the small tube
c = .6; % the diameter of the bulb
t1 = pi/4 : pi/n : 5*pi/4; % parameter along the tube
t2 = 5*pi/4 : pi/n : 9*pi/4; % angle around the tube
u = pi/2 : pi/n : 5*pi/2;
[X,Z1] = meshgrid(t1,u);
[Y,Z2] = meshgrid(t2,u);

% The handle
len = sqrt(sin(X).^2 + cos(2*X).^2);
x1 = c*ones(size(X)).*(cos(X).*sin(X) ...
- 0.5*ones(size(X))+a*sin(Z1).*sin(X)./len);
y1 = a*c*cos(Z1).*ones(size(X));
z1 = ones(size(X)).*cos(X) + a*c*sin(Z1).*cos(2*X)./len;
handleHndl=surf(x1,y1,z1,X);
set(handleHndl,'EdgeColor',[.5 .5 .5]);
hold on;

% The bulb
r = sin(Y) .* cos(Y) - (a + 1/2) * ones(size(Y));
x2 = c * sin(Z2) .* r;
y2 = - c * cos(Z2) .* r;
z2 = ones(size(Y)) .* cos(Y);
bulbHndl=surf(x2,y2,z2,Y);
set(bulbHndl,'EdgeColor',[.5 .5 .5])

colormap(hsv);
axis vis3d
view(-37,30);
axis off
light('Position',[2 -4 5])
light
hold off
From: Per Sundqvist on 26 Jan 2010 08:35
"striker " <friend_019(a)hotmail.com> wrote in message <hjmmpb$6v4$1(a)fred.mathworks.com>...
> I just want to create a model which looks like a banana.so that i can rotate it along any axis and i can scale it in any direction.

look at:
http://www.mathworks.com/matlabcentral/fileexchange/5562-tubeplot

or mine:
http://www.mathworks.com/matlabcentral/fileexchange/5468-cylinder-between-2-points

Not sure you can alter the radii along the tube for the first function. Paerhaps its a start?

/Per
From: striker on 26 Jan 2010 08:36
Yes the banana shape is important
First  |  Prev  |  Next  |  Last
Pages: 1 2 3
Prev: Code for image segmentation using water reservior technique
Next: code for image segmentation