Sunday, 7 September 2014

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:


Thursday, 17 July 2014

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

Tuesday, 15 July 2014

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

Saturday, 12 July 2014

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');
=====================================================================

Wednesday, 7 May 2014

Reading audio file and removing background noise and saving it back using MATLAB

To read an audio file or to make an audio file..
1. Attach ur hands free that comes with ur mobile that has microphone /headset with microphone to the computer
2.In windows 7,  Go to Start->All Programs ->Accessories ->Sound Recorder
On the Floating window of sound recorder, Click on Start Recording
Now speak to the microphone ..Once done click on STOP recording and save the audio file in D: drive as lp.wma

%To read an audio file to matlab use audioread as shown below
y = audioread('d:/lp.wma');

%To remove background noise, use adaptive filter

n=1:length(y);
mtlb_noisy = y;
noise = n;
% Define Adaptive Filter Parameters
filterLength = 32;
weights = zeros(1,filterLength);
step_size = 0.004;
% Initialize Filter's Operational inputs
output = zeros(1,length(mtlb_noisy));
err = zeros(1,length(mtlb_noisy));
input = zeros(1,filterLength);
% For Loop to run through the data and filter out noise
for n = 1: length(mtlb_noisy),
%Get input vector to filter
for k= 1:filterLength
if ((n-k)>0)
input(k) = noise(n-k+1);
end
end
output(n) = weights * input';  %Output of Adaptive Filter
err(n)  = mtlb_noisy(n) - output(n); %Error Computation
weights = weights + step_size * err(n) * input; %Weights Updating
end
yClean = err;

% to save the output to D drive and with name re.mp4

audiowrite('d:/re.mp4',output,44100);