MATLAB is a programming language developed by MathWorks. It started out as a matrix programming language where linear algebra programming was simple. It can be run both under interactive sessions and as a batch job.
Most MATLAB scripts and functions can be run in the open source programme octave. This is freely available for most computing platforms.
GNU Octave and LabVIEW MathScript are systems for numerical computations with an m-file script language that is mostly compatible with MATLAB. Both alternatives can replace MATLAB in many circumstances. While a good deal of the content of this book will also apply to both Octave and LabVIEW MathScript, it is not guaranteed to work in exactly the same manner. Differences and comparison between MATLAB and Octave are presented in Comparing Octave and MATLAB.
A Tutorial IntroductionEdit
Basic MATLAB ConceptsEdit
Saving and loading a MAT-file
Edit
-
- Commands
- File Naming conventions
- Basic Reading and Writing data from a file
clc; clear all; close all;
[filename, pathname] = uigetfile( {'*.jpg';'*.bmp'}); aa=imread([pathname,filename]); I=aa; bb=imresize(aa,[256 256]); imshow(bb);title('input image');
%%...............%%% RGB2Lab color conversion %%%.........
rgbimage=makecform('srgb2lab'); labimage=applycform(bb,rgbimage); figure, imshow(labimage);title('color conversion image');
%%..............%%% seperate L* a* b* color space %%%.........
L=im2double(labimage(:,:,1)); a=im2double(labimage(:,:,2)); b=im2double(labimage(:,:,3)); figure,imshow(L);title('L* image'); [h,w,o]=size(L);
%%..........%%% applying filter in L* color space %%%..........
for s=1:3
W(s)=h/2^s;
for i=1:h
for j=1:w
p=(i-W(s));
q=(i+W(s));
r=(j-W(s));
t=(j+W(s));
if p<=0
p=1;
end
if q>256
q=256;
end
if r<=0
r=1;
end
if t>256
t=256;
end
m=p:q;
n=r:t;
%N(s)=W(s)*W(s);
N(s)=size(m,2)*size(n,2);
sum1=sum(sum(L(m,n)));
V=1/N(s);
A=V*sum1;
B(i,j)=L(i,j)-A;
end
end
%B=L-A;
%figure,imshow(B);
azx(:,:,s)=B;
end
contrast_L=azx(:,:,1)+azx(:,:,2)+azx(:,:,3); figure,imshow(contrast_L),title('contrast map L* image');
%%..............%%% find inverse of a* %%%............
figure,imshow(a);title('a* image'); d=max(max(a)); yy=d-a; yy=(yy*5); figure,imshow(yy);title('inv a* image'); [h,w,o]=size(yy);
%%.............%%% applying filter in a* color space %%%........
for s=1:3
W(s)=h/2^s;
for i=1:h
for j=1:w
p=(i-W(s));
q=(i+W(s));
r=(j-W(s));
t=(j+W(s));
if p<=0
p=1;
end
if q>256
q=256;
end
if r<=0
r=1;
end
if t>256
t=256;
end
m=p:q;
n=r:t;
%N(s)=W(s)*W(s);
N(s)=size(m,2)*size(n,2);
sum1=sum(sum(yy(m,n)));
V=1/N(s);
A=V*sum1;
C(i,j)=yy(i,j)-A;
end
end
%C=L-A;
%figure,imshow(C);
aza(:,:,s)=C;
end
contrast_a=aza(:,:,1)+aza(:,:,2)+aza(:,:,3); figure,imshow(contrast_a),title('contrast map a* image');
%%.............%%% find final scaling contrast map %%%.......
Scaling_contrast=imadd(contrast_L,contrast_a); figure,imshow(Scaling_contrast),title('Scaling contrast map');
%%...........%%% gabor filter outputs %%%.......................
[gabor_timage,u,v,GT,filter]=final_gabor(aa);
%%..........%%% removing erythema & dark pixels %%%..........
ts=0.4; %% set threshold value R=Scaling_contrast; for i=1:h
for j=1:w
if Scaling_contrast(i,j)>=ts
R(i,j)=1;
else
R(i,j)=0;
end
end
end
figure,imshow(R);title('Removing erythema');
The MATLAB Command PromptEdit
-
- Calculator
Data Storage and ManipulationEdit
GraphicsEdit
Graphics
Edit
Handle GraphicsEdit
- What is a handle?
- Figure handles
- Axis handles
- Other types of handles
Annotating PlotsEdit
M-file ProgrammingEdit
Numerical ManipulationEdit
Linear AlgebraEdit
It is the Matrix laboratory after all.
-
- Operations
- Transpose
- Systems of linear equations
-
- Row reduced echelon form
- Inverse
- Coffactor, minor
- Jacobian
Differential EquationsEdit
More advanced I/OEdit
Different versions of MATLAB handle this differently. We will focus on versions 6.5 and 7.x, primarily on MATLAB 7.x since it is the latest. A note will appear when the procedure is different for ver. 6.
Reading and writing from filesEdit
Writing and Reading to A Serial PortEdit
Writing to a USB portEdit
ExamplesEdit
FilteringEdit
-
- Moving Average
- Alpha Beta
- Kalman
-
- PSD estimation
- Entropy
- Markov Processes
- Queuing Theory
ControlsEdit
Phase vocoderEdit
See "Phase vocoder and encoder in MATLAB" for an example phase vocoder and the corresponding sound sample encoder in MATLAB.
Object Oriented ProgrammingEdit
MATLAB as well as Octave have object oriented capabilities. Yet, technically it is not fully an object oriented language.
An Object Oriented Language(OOL) has three components: 1. Polymorphism 2. Inheritance 3. Encapsulation
Octave can be extended by adding new objects. Those objects can overload the operators like e.g. assignment, slicing, comparison.
While in MATLAB, this can be done with m-script, in Octave new objects are implemented as C++ classes. A simple example of how objects can be added to Octave can be found here.
Struct arraysEdit
MATLAB classes
Edit
An alternative to MATLAB: OctaveEdit
What is Octave ?Edit
A short presentation of Octave and its history.
Differences between Octave and MATLABEdit
The most important differences between Octave and MATLAB that anyone willing to use Octave instead of MATLAB should be aware of.
Toolboxes and ExtensionsEdit
The toolboxes are pretty good if you can afford them. In version 7 there are a lot of toolboxes.
Symbolic Toolbox
Edit
Image Processing ToolboxEdit
MATLAB CompilerEdit
Legacy ToolboxesEdit
- GUIDE allows the creation of interactive user interfaces.
- Simulink is for modeling, simulating and analysing systems.
- Psychtoolbox is a set of tools that aid in vision research.
- Distributed computing- The distributed computing toolbox is a set of tools that aid in distributing models over a cluster.
- Optimization- The optimization toolbox includes various algorithms for minimization.
MATLAB in medicineEdit
„Image Processing in Optical Coherence Tomography using Matlab” is a book which will introduce you to subtleties related to the implementation of selected fragments of algorithms, the notation of some of them in the MATLAB environment has been given. The presented source code is shown only in the form of example of implementable selected algorithm. The book is addressed to ophthalmologists , IT specialists and students involved in the development of applications designed for automation of measurements for the needs of medicine.
ReferencesEdit
- MATLAB documentation from The MathWorks.
- MATLAB programs compilation from 'MATLAB programs for Engineering Students'.
External linksEdit
Other WikibooksEdit
A number of other wikibooks use MATLAB to teach their subjects. The following wikibooks make use of MATLAB:
OrganizationEdit
