Applying affine transformation (rotate, scale and translate) to align 2 shapes

s(:,1)=[20 40 40 20]';

s(:,2)=[20 20 40 40]';

plot(s(:,1),s(:,2),'.g');title('Reference Shape');

refv=s(:);

d(:,1)=[30 40 30 20];

d(:,2)=[20 30 40 30];

plot(d(:,1),d(:,2),'.g');title('Shape to be aligned');

v=d(:);

[x, y] = COG( v ); %[x,y]=[30,30]

v = Translate( v, x, y); %v-(x,y)

[x, y] = COG( refv ); % here COG is same for both

refv = Translate( refv, x, y);

vSize = Norm2( v ); %square all of them and then sum and find square root.

refvSize = Norm2( refv );

v = Scale( v, refvSize / vSize ); % refvSize / vSize gives how much reference shape is more in scale %than v and so multiply v with that it is less of .

t=v+30;

plot(t(1:4),t(5:8),'.g');

r=GetRotation( refv, v )

re = Rotate( v, r )

re=re+30;

plot(re(1:4),re(5:8),'.g');

the below figure shows that the 2 shapes are aligned.

===================================================

function [x, y] = COG( v )

n = size(v, 1) / 2;

x = sum(v(1:n, 1)) / n;

y = sum(v(n+1:2*n, 1)) / n;

function r = Translate( v, x, y)

[h, w] = size(v);

n = h / 2;

r = zeros(h, w);

r(1:n, 1) = v(1:n, 1) - x;

r(n+1:2*n, 1) = v(n+1:2*n, 1) - y;

function r = Norm2( v )

r = sqrt(sum(v.^2'));

function r = Scale( v, scale )

r = v.* scale;

====================================================

To filter out rotational effects, the following Singular Value Decomposition is used as suggested by Bookstein [1]:

1. Arrange the size and position of aligned shapes x1 and x2 as n x k matrices.

2. Calculate the SVD, UDVT, of  VUT

3. Then the rotation matrix needed to optimally superimpose x1upon x2 is VUT. In the planar case:

function r = GetRotation( refv, v )

                          

n = size( refv, 1 ) / 2;

refs = reshape( refv, n, 2 );

s = reshape( v, n, 2 );

res = refs' * s; %(reference shape ‘ *shape) we get a 2x2 matrix

[U,S,V] = svd( res );

res = V * U';

cos_theta = res(1,1);

sin_theta = res(2,1);

epsilon = 1e-12;

if 1 - cos_theta < epsilon

   r = 0;

elseif abs(cos_theta) < epsilon

   r = pi / 2;

elseif 1 + cos_theta < epsilon

   r = pi;

else

   a_cos = acos( cos_theta );

   a_sin = asin( sin_theta );

   if a_sin < 0

       r = -a_cos;

   else

       r = a_cos;

   end

end
========================================================

 function r = Rotate( v, theta)
rm = [ cos( theta ) sin( theta ); -sin( theta ) cos( theta ) ];
n = size( v, 1) / 2;
s = reshape( v, n, 2 );
for i = 1 : n
    s(i,:) = s(i,:) * rm;
end
r = reshape( s, n*2, 1 );

[1] M. B. Stegmann, Active Appearance Models: Theory, Extensions and Cases, pp. 262, Informatics and Mathematical Modelling, Technical University of Denmark, DTU, 2000.

All the above functions are written by WANG Lei, CG&CV Lab, Hunan University, Changsha

% $Id: ModelAAM.m, v 1.2 2004-4-16 15:17 Lei$

to print natural numbers repeating each number fixed number of times

To generate output as shown below:
1
1
1
2
2
2
3
3
3

the code is
myfun=[];
for i = 1:3
temp=ones(3,1)*i; %the first parameter in ones function i,e, 3 can be changed to any number, say 6 to print six 1's and then six 2's and so on......
myfun= [myfun;temp];
end

How to draw a circle on detected face using vision toolbox in matlab with center of the circle highlighted

I = imread('KA.SA3.35.png');% this image has been extracted from japanese female expression %database
bb=step(fdetect,I);
c=bb(3)/2;
d=bb(4)/2;
cx=bb(1)+c
cy=bb(2)+d
position=[cx,cy,c];
videoout=insertObjectAnnotation(I,'circle',position,'face');
imshow(videoout);
hold on; plot(cx,cy,'+','MarkerSize',10);
hold off;

Results:

creating simple calculator using guide in MATLAB

Check the example videos that come with MATLAB.

I have also provided links to videos you can look to create simple basic GUIs at the end of this post.

The code in purple is autogenerated by guide in MATLAB.

I have written the code that is in black.

Check this link to understand better after the example videos in MATLAB documentation.

http://blogs.mathworks.com/videos/2013/02/06/introduction-to-gui-building-with-guide-in-matlab/

My calculator looks like this

function varargout = myCalculator(varargin)
% MYCALCULATOR MATLAB code for myCalculator.fig
%      MYCALCULATOR, by itself, creates a new MYCALCULATOR or raises the existing
%      singleton*.
%
%      H = MYCALCULATOR returns the handle to a new MYCALCULATOR or the handle to
%      the existing singleton*.
%
%      MYCALCULATOR('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in MYCALCULATOR.M with the given input arguments.
%
%      MYCALCULATOR('Property','Value',...) creates a new MYCALCULATOR or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before myCalculator_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to myCalculator_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%
% See also: GUIDE, GUIDATA, GUIHANDLES

% Edit the above text to modify the response to help myCalculator

% Last Modified by GUIDE v2.5 18-Jul-2014 00:14:02

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @myCalculator_OpeningFcn, ...
                   'gui_OutputFcn',  @myCalculator_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{1})
    gui_State.gui_Callback = str2func(varargin{1});
end

if nargout
    [varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});
else
    gui_mainfcn(gui_State, varargin{:});
end
% End initialization code - DO NOT EDIT


% --- Executes just before myCalculator is made visible.
function myCalculator_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to myCalculator (see VARARGIN)

% Choose default command line output for myCalculator
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes myCalculator wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = myCalculator_OutputFcn(hObject, eventdata, handles) 
% varargout  cell array for returning output args (see VARARGOUT);
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Get default command line output from handles structure
varargout{1} = handles.output;


% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
first=get(handles.edit2,'string');
first=str2double(first);
second=get(handles.edit3,'string');
second=str2double(second);
sum=first+second;
set(handles.edit1,'string',sum);


% --- Executes on button press in pushbutton2.
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
first=get(handles.edit2,'string');
first=str2double(first);
second=get(handles.edit3,'string');
second=str2double(second);
divide=first/second;
set(handles.edit1,'string',divide);


% --- Executes on button press in pushbutton3.
function pushbutton3_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
first=get(handles.edit2,'string');
first=str2double(first);
second=get(handles.edit3,'string');
second=str2double(second);
mul=first*second;
set(handles.edit1,'string',mul);


% --- Executes on button press in pushbutton4.
function pushbutton4_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton4 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
first=get(handles.edit2,'string');
first=str2double(first);
second=get(handles.edit3,'string');
second=str2double(second);
sub=first-second;
set(handles.edit1,'string',sub);


% --- Executes on button press in pushbutton5.
function pushbutton5_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton5 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
first=get(handles.edit2,'string');
first=str2double(first);
second=get(handles.edit3,'string');
second=str2double(second);
exp=first^second;
set(handles.edit1,'string',exp);


function edit1_Callback(hObject, eventdata, handles)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit1 as text
%        str2double(get(hObject,'String')) returns contents of edit1 as a double


% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end



function edit2_Callback(hObject, eventdata, handles)
% hObject    handle to edit2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit2 as text
%        str2double(get(hObject,'String')) returns contents of edit2 as a double


% --- Executes during object creation, after setting all properties.
function edit2_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end



function edit3_Callback(hObject, eventdata, handles)
% hObject    handle to edit3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% Hints: get(hObject,'String') returns contents of edit3 as text
%        str2double(get(hObject,'String')) returns contents of edit3 as a double


% --- Executes during object creation, after setting all properties.
function edit3_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit3 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    empty - handles not created until after all CreateFcns called

% Hint: edit controls usually have a white background on Windows.
%       See ISPC and COMPUTER.
if ispc && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
    set(hObject,'BackgroundColor','white');
end

Other Links :

http://blogs.mathworks.com/videos/2013/02/06/introduction-to-gui-building-with-guide-in-matlab/

http://blogs.mathworks.com/videos/2008/04/17/advanced-matlab-handles-and-other-inputs-to-guide-callbacks/

http://blogs.mathworks.com/videos/2008/04/08/widgetpalooza-12-widgets-coded-up-in-a-gui/

http://blogs.mathworks.com/videos/2014/05/22/adding-callbacks-to-lines-and-axes-in-matlab/

http://blogs.mathworks.com/videos/2014/05/12/interuptable-callbacks-and-busyaction-in-matlab/

http://blogs.mathworks.com/videos/2008/03/31/puzzler-coin-game/
http://matlabbyexamples.blogspot.in/2011/10/multipages-gui-forms-combining-from.html

reading inbuilt MATLAB video and saving every fifth frame to C: drive frames folder

reading inbuilt MATLAB video and saving every fifth frame to C: drive frames folder
clear all;
videoObject = mmreader('xylophone.mpg');
nFrames = videoObject.NumberOfFrames;
OutputPath='C:/frames/';
mkdir(OutputPath);
for i=1:nFrames
if(mod(i,5) == 0)

fileName=strcat(OutputPath,int2str(i),'.jpg');
frameRead = read(videoObject, i);  
imwrite(frameRead,fileName);

end
end

making a video out of images in matlab

=====================In older versions of MATLAB========================

samples_dir='C:/data'; % data is folder name that has images

files = dir([samples_dir , '\*.jpg']);
aviObj = avifile('C:\test.avi', 'Compression', 'MSVC'); %test.avi is the name of the video and gets stored
%addframe cannot be used for true color images, so convert to gray scale and then add 

%video quality is not good

for i=1:length(files)
f_bmp=[samples_dir '\' files(i).name];
img=imread(f_bmp);
gr=rgb2gray(img);
aviObj = addframe(aviObj, gr);
end
aviObj=close(aviObj);

===================In newer versions of MATLAB===========================
 clear all;
close all;
samples_dir='C:/data'; % data is folder name that has images

Files = dir([samples_dir , '\*.jpg']);

VideoFile='C:\data\MyVideo'; %path of the video file to be saved
writerObj = VideoWriter(VideoFile);
writerObj.FrameRate =1; %increase the frame rate, here i have used 1 frame per second
open(writerObj);
for t= 1:length(Files)
Frame=imread(strcat('C:\data','\',Files(t).name));
writeVideo(writerObj,im2frame(Frame));
end
close(writerObj);

%To play the video

videoFReader = vision.VideoFileReader('C:\data\MyVideo.avi');
videoPlayer = vision.VideoPlayer;
while ~isDone(videoFReader)
   frame = step(videoFReader);
   step(videoPlayer,frame);
end
release(videoFReader);
release(videoPlayer);
                                                  (or)
implay('C:/data/MyVideo.avi');

=============================================================================

Program to read images in a directory as a video

===========================================================================

samples_dir='C:/data'; % data is folder name that has images

files = dir([samples_dir , '\*.jpg']);

hVPlayer=vision.VideoPlayer;
for i=1:length(files)
f_bmp=[samples_dir '\' files(i).name];
img=imread(f_bmp);
step(hVPlayer,img);
end

release(hVPlayer);

====Reading a 'mpg' video inbuilt in MATLAB and displaying the 36th,72nd,108th and 141th frame.======

clear all;
close all;
videobj=mmreader('xylophone.mpg');
numframes=get(videobj,'numberofframes');

x=read(videobj,36);
y=read(videobj,72);
z=read(videobj,108);
k=read(videobj,141);
subplot(221);imshow(x);title('36th frame');
subplot(222);imshow(y);title('72th frame');
subplot(223);imshow(z);title('108th frame');
subplot(224);imshow(k);title('141th frame');

=====================================================================