Gettingstartedwithmatlabimageprocessing

Introduction
 Cleve molar in 1984, Mathworks inc
 Introduced as a simulation tool
 Supports Graphical Programming
 Can be interfaced with other High
Level languages
Technology beyond the Dreams™ Copyright © 2006 Pantech Solutions Pvt Ltd.

Applications
• Aerospace
• Biometrics
• Medical
• Finance
• Control System
• Signal,Image,Audio and Video
• Neural networks,Fuzzy logic
• Animation

List of Companies
• ADOBE (Photoshop)
• NASA
• GE
• L&T
• ROBERT BOSCH
• PEPSI , COCACOLA (Neuro Marketing)

File Extensions
.fig
MATLAB Figure
.m
MATLAB function, script, or class
.mat
MATLAB binary file for storing variables
.mex
MATLAB executable (platform specific, e.g. ".mexmac" for the
Mac, ".mexglx" for Linux, etc.)
.p
MATLAB content-obscured .m file (result of pcode() )

Difference between C and Matlab
• Matlab is Proprietary compiler,C has open source.
• Inbuilt Functions in Matlab(Application Oriented).
• User friendly syntax.
• Fourth generation Programming Language tool.

Desktop Tools
• Command Window
– type commands
• Workspace
– view program variables
– clear to clear
– double click on a variable to see it in the Array Editor
• Command History
– view past commands
– save a whole session using diary
• Launch Pad
– access tools, demos and documentation

Command window

Change the current working
directory

Arithmetic operators
1) plus - Plus +
2) uplus - Unary plus +
3) minus - Minus -
4) uminus - Unary minus -
5) mtimes - Matrix multiply *
6) times - Array multiply .*
7) mpower - Matrix power ^
8) power - Array power .^
9) mldivide - Backslash or left matrix divide
10) mrdivide - Slash or right matrix divide /
11) ldivide - Left array divide .
12) rdivide - Right array divide ./

Relational operators
1) eq - Equal ==
2) ne - Not equal ~=
3) lt - Less than <
4) gt - Greater than >
5) le - Less than or equal <=
6) ge - Greater than or equal >=

Logical operators
1) Short-circuit logical AND &&
2) Short-circuit logical OR ||
3) and - Element-wise logical AND &
4) or - Element-wise logical OR |
5) not - Logical NOT ~
6) xor - Logical EXCLUSIVE OR
7) any - True if any element of vector is nonzero
8) all - True if all elements of vector are nonzero

BITWISE OPERATORS
1) bitand - Bit-wise AND.
2) bitcmp - Complement bits.
3) bitor - Bit-wise OR.
4) bitmax - Maximum floating point
integer.
5) bitxor - Bit-wise XOR.
6) bitset - Set bit.
7) bitget - Get bit.
8) bitshift - Bit-wise shift.

Vectors
a = [1 2 3 4 5 6 9 8 7] ;
t = 0:2:20
t = 0 2 4 6 8 10 12 14 16 18 20
b = a + 2
b = 3 4 5 6 7 8 11 10 9
c = a + b
c = 4 6 8 10 12 14 20 18 16

Matrices
B = [1 2 3 4;5 6 7 8;9 10 11 12] ;
B = 1 2 3 4
5 6 7 8
9 10 11 12
C = B'
C = 1 5 9
2 6 10
3 7 11
4 8 12

Basic matrix operators
X = inv(E) ;%INVERSE OF THE MATRIX
[A,H] = eig(E) %eigen value &vector
p = poly(E) %polynomial
c = abs(y) ;
D=min(a);
D=max(a);
• Convolution
x = [1 2];
y = [1 4 8];
z = conv(x,y)
[xx, R] = deconv(z,y)

PLOT
t=0:0.25:7;
y = sin(t);
plot(t,y) ;
xlabel('x axis');
ylabel('y axis');
title('Heading');
grid on;
gtext('text');

IF LOOP
a=6;
if a > 6
disp('a is greater');
elseif a==0
disp('a is zero');
else
disp('a is smaller');
end

FOR LOOP
a=5;
for i=1:5
a=a+1
end
disp(a);
ANS a =10

While Loop
a=5;
while a < 10
a=a+1;
end
disp(a);
Ans a =10

Function
function c=add(a,b);
c=a+b;
return
Main
a=5;
b=6;
c=add(a,b);
disp(c);
d=mul(a,b);
disp(d);
function c=mul(a,b);
c=a*b;
return

SWITCH CASE
method = 'Bilinear';
switch lower(METHOD)
case {'linear','bilinear'}
disp('Method is linear')
case 'cubic'
disp('Method is cubic')
case 'nearest'
disp('Method is nearest')
otherwise
disp('Unknown method.')
end
Ans Method is linear

SWITCH (NUMERICAL)
a=input('enter---->');
switch a
case 1
fprintf('one');
case 2
fprintf('two');
case 3
fprintf('three');
case 4
fprintf('four');
otherwise
fprintf('otherwise');
end

How to read an image
a =imread('cameraman.tif');
imshow(a);
pixval on;
a =imread('flowers.tif');
imshow(a);
pixval on;

How to read an audio file
a =wavread('test.wav');
wavplay(a,44100);
Plot(a);

How to read an video file
a=aviread('movie.avi');
movie(a);

Add two images
I = imread('rice.tif');
J = imread('cameraman.tif');
K = imadd(I,J,'uint16');
imshow(K,[])
J = imadd(I,50);
subplot(1,2,1), imshow(I)
subplot(1,2,2), imshow(J)

Subtract two images
Iq = imsubtract(I,50);
subplot(1,2,1), imshow(I)
subplot(1,2,2), imshow(Iq)

Convert image to gray and binary
clc;
clear;
close all
a= imread('flowers.tif');
subplot(2,2,1);
imshow(a);
subplot(2,2,2);
b=imresize(a,[256 256]);
imshow(b);
subplot(2,2,3);
c=rgb2gray(b);
imshow(c);
subplot(2,2,4);
d=im2bw(c);
imshow(d);

RGB component
a=imread('flowers.tif');
subplot(2,2,1);
imshow(a);
R=a;
G=a;
B=a;
R(:,:,2:3)=0;
subplot(2,2,2);
imshow(R);
G(:,:,1)=0;
G(:,:,3)=0;
subplot(2,2,3);
imshow(G);
B(:,:,1)=0;
B(:,:,2)=0;
subplot(2,2,4);
imshow(B);

Convert Image into One dimensional
a = imread('cameraman.tif');
[r c]=size(a);
Len=r*c;
b=reshape(a,[1 Len]);

CONVER MOVIE TO FRAMES
file=aviinfo('movie1.avi'); % to get inforamtaion abt video file
frm_cnt=file.NumFrames % No.of frames in the video file
str2='.bmp'
h = waitbar(0,'Please wait...');
for i=1:frm_cnt
frm(i)=aviread(filename,i); % read the Video file
frm_name=frame2im(frm(i)); % Convert Frame to image file
frm_name=rgb2gray(frm_name);%convert gray
filename1=strcat(strcat(num2str(i)),str2);
imwrite(frm_name,filename1); % Write image file
waitbar(i/frm_cnt,h)
end
close(h)

CONVERT FRAMES TO MOVIES
frm_cnt=5;
number_of_frames=frm_cnt;
filetype='.bmp';
display_time_of_frame=1;
mov = avifile('MOVIE.avi');
count=0;
for i=1:number_of_frames
name1=strcat(num2str(i),filetype);
a=imread(name1);
while count<display_time_of_frame
count=count+1;
imshow(a);
F=getframe(gca);
mov=addframe(mov,F);
end
count=0;
end
mov=close(mov);

How to read a text file
fid = fopen('message.txt','r');
ice1= fread(fid);
s = char(ice1');
fclose(fid);
disp(s);
Ans hello

How to write a text file
txt=[65 67 68 69];
fid = fopen('output.txt','wb');
fwrite(fid,char(txt),'char');
fclose(fid);
ANS =ACDE

Store an Image,Audio
imwrite(a,'new.bmp');
a=wavread('test.wav');
wavwrite(d,44100,16,'nTEST.WAV');

SAVE AND LOAD THE VARIABLE
A=5;
save A A;
load A
B=1;
C=A+B;
disp(C);

Wavelet transform
[LL LH HL HH]=dwt2(a,'haar');
Dec=[...
LL,LH
HL,HH
...
];
imshow(Dec,[]);

DCT transform
a=imread('cameraman.tif');
subplot(1,3,1);imshow(a,[]);
b=dct2(a);
subplot(1,3,2);imshow(b,[]);title('DCT');
c=idct2(b);
subplot(1,3,3);imshow(c,[]);title('IDCT');

NOISE AND FILTER
I = imread('eight.tif');
J = imnoise(I,'salt & pepper',0.02);
K = medfilt2(J);
subplot(1,2,1);imshow(J)
subplot(1,2,2);imshow(K)

GUI

DIALOG BOX
warndlg('hello'); helpdlg('hello'); errordlg('hello');
msgbox('hello');

ButtonName=questdlg('What is your wish?', ...
'Genie Question', ...
'Food','Clothing','Money','Money');
switch ButtonName,
case 'Food',
disp('Food is delivered');
case 'Clothing',
disp('The Emperor''s new clothes have arrived.')
case 'Money',
disp('A ton of money falls out the sky.');
end % switch

USER INTERFACE GET FILE
[filename, pathname] = uigetfile('*.m', 'Pick an M-file');
if isequal(filename,0) | isequal(pathname,0)
disp('User pressed cancel')
else
disp(['User selected ', fullfile(pathname, filename)])
end

USER INTERFACE PUT FILE
[filename, pathname] = uiputfile('*.m', 'Pick an M-file');
disp('User pressed cancel')
else
disp(['User selected ', fullfile(pathname, filename)])
end

GUI…

MENU BAR

PUSH BUTTON

TOGGLE BUTTON

RADIO BUTTON

CHECKBOX

EDIT TEXT

STATIC TEXT

SLIDER

FRAME

LISTBOX

POPUP MENU

AXES

ALIGN OBJECTS

MENU EDITOR

M FILE EDITOR

PROPERTY INSPECTOR

RUN

EMPTY GUI

GENERATED M FILE

RIGHT CLICK PUSH BUTTON & GO
FOR PROPERTY INSPECTOR

CHANGE THE STRING AND TAG
VALUE

RIGHT CLICK PUSH BUTTON & GO
FOR M FILE EDITOR

GO FOR CALLBACK

WRITE THE CODE BELOW THE
CALLBACK
imshow(a);

RUN THE PROGRAM OR PRESS F5

CHOOSE AXES

RIGHT CLICK AXES & GO FOR
PROPERTY INSPECTOR

CALLBACK
axes(handles.one);
imshow(a);

RUN THE PROGRAM

CODE
axes(handles.one);
imshow(a);

RIGHT CLICK TOGGLE & GO FOR
PROPERTY INSPECTOR

RIGHT CLICK TOGGLE & GO FOR M
FILE EDITOR

CALLBACK
a=get(hObject,'Value');
if a ==1
axes(handles.one);
imshow(a);
else
a =imread('greens.jpg');
axes(handles.one);
imshow(a);
end

RIGHT CLICK RADIO BUTTON & GO

RIGHT CLICK CHECK BOX & GO
FOR MFILE EDITOR

CALLBACK

FOR M FILE EDITOR

RIGHT CLICK FRAME & SEND TO
BACK

RIGHT CLICK LIST BOX & GO FOR
PROPERTY INSPECTOR

EDIT THE STRING OPTIONS

RIGHT CLICK LIST BOX & GO FOR M
FILE EDITOR

CALLBACK contents = get(hObject,'Value')
switch contents
case 1
axes(handles.one);
imshow(a);
case 2
axes(handles.one);
imshow(a);
case 3
a =imread('rice.tif');
axes(handles.one);
imshow(a);
otherwise
a =imread('mri.tif');
axes(handles.one);
imshow(a);
end

CHOOSE POPUPMENU

RIGHT CLICK POPUP MENU & GO

WRITE THE CODE
contents = get(hObject,'Value')
switch contents
case 1
axes(handles.one);
imshow(a);
case 2
axes(handles.one);
imshow(a);
case 3
a =imread('rice.tif');
axes(handles.one);
imshow(a);
otherwise
a =imread('mri.tif');
axes(handles.one);
imshow(a);
end

RIGHT CLICK EDIT TEXT & GO FOR
PROPERTY INSPECTOR

EDIT STRING AND TAG

RIGHT CLICK EDIT TEXT & GO FOR
M FILE EDITOR

CALLBACK
a=get(hObject,'String') ;
b=char(a);
c=imread(b);
axes(handles.one);
imshow(c);

RIGHT CLICK STATIC TEXT & GO

CALLBACK
a=get(hObject,'String') ;
set(handles.t1,'String',a);
b=char(a);
c=imread(b);
axes(handles.one);
imshow(c);

RIGHT CLICK SLIDER & GO FOR
PROPERTY INSPECTOR

DROP TWO AXES

DROP PUSH BUTTON

CALLBACK
[filename, pathname] = uigetfile('*.bmp', 'Pick an Image');
warndlg('User pressed cancel')
else
a=imread(filename);
axes(handles.axes1);
imshow(a);
handles.filename=filename;
guidata(hObject, handles);
end

RIGHT CLICK SLIDER & GO FOR M
FILE EDITOR

RUN THE PROGRAM
a=get(hObject,'Value');
filename =handles.filename;
I = imread(filename);
J = imadd(I,50);
axes(handles.axes2);
imshow(J)

Counting the Number of Objects in
an Image
clc;
clear;
close all;
InputImage=imread('eight.tif');
subplot(2,2,1);
imshow(InputImage);title('InputImage');
BinaryImage=im2bw(InputImage);
subplot(2,2,2);
imshow(BinaryImage);
ComplementImage=imcomplement(BinaryImage);
subplot(2,2,3);
imshow(ComplementImage);
HolesClearedImage = imfill(ComplementImage,'holes');
subplot(2,2,4);
imshow(HolesClearedImage);title('HolesClearedImage');
[L,Num] = bwlabel(HolesClearedImage)
for i=1:Num
figure;
imshow(L==i);
pause(1)
end

Thresholding Based Segmentation-
Con 1
• clc;
• clear;
• close all;
• InputImage=imread('34.bmp');
• figure;
• imshow(InputImage);
• ColourSpaceConversion=rgb2hsv(InputImage);
• imshow(ColourSpaceConversion);
• %GrayScaleImage=rgb2gray(ColourSpaceConversion);
• GrayScaleImage=ColourSpaceConversion(:,:,1);
• [rows columns planes]=size(GrayScaleImage);
• BinaryMask= GrayScaleImage > 0.5;
• figure;
• imshow(BinaryMask);
• Impixelinfo
• h = waitbar(0,'Please wait...');
• SegmentedImage=[];

Cont 2
for i=1:rows
for j=1:columns
if BinaryMask(i,j) == 1
SegmentedImage(i,j,1)=InputImage(i,j,1);
else
SegmentedImage(i,j,1)=0;
end
end
waitbar(i/rows,h)
end
SegmentedImage=uint8(SegmentedImage);
figure;
imshow(SegmentedImage);
impixelinfo;

Image Fusion
clc;
clear;
close all;
M1=imread('mri.jpg');
M2=imread('ct.jpg');
subplot(2,2,1);imshow(M1);title('MRI');
subplot(2,2,2);imshow(M2);title('CT');
[R C P]=size(M1);
for i=1:R
for j=1:C
if M1(i,j)>M2(i,j)
FusedImage(i,j)=M1(i,j);
else
end
end
end

Image fusion-Cont 2
subplot(2,2,3);imshow(FusedImage);title('Max');
for i=1:R
for j=1:C
if M1(i,j)>M2(i,j)
else
end
end
end
subplot(2,2,4);imshow(FusedImage);title('Min');

For more details
– www.pantechsolutions.net
– http://www.slideshare.net/pantechsolutions
– http://www.scribd.com/pantechsolutions
– http://www.youtube.com/pantechsolutions

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