Codes

Pseudocolor Image processing

% program for pseudo color image processing no 2

% here each graylevel has been assigned a different color

clc; clear all; close all;

y=imread('scan0004.jpg');

e=0;

% y=rgb2gray(y);

y=im2double(y);

e=y;

g=0;

[p,q,r]=size(y);

% find the average gray level

for i=1:p

for j=1:q

u=y(i,j);

g=g+u;

end

u=y(i,j);

g=g+u;

end

pq=p*q;

s=g/pq;

s=round(s*100);

r1 = round(s/3);

mi=255-s;

r2 = round(mi/3);

y=y*100;

y=round(y);

for i=1:p

for j=1:q

if (y(i,j) >= 0) && (y(i,j) < r1)

t=y(i,j);

f=(255/r1)*t;

x(i,j,1)=f;

x(i,j,2)=192;

x(i,j,3)=128;

elseif (y(i,j) >= r1) && (y(i,j) < (2*r1));

t=y(i,j);

z=t-85;

f=(255/r1)*z;

x(i,j,1)=192;

x(i,j,2)=z;

x(i,j,3)=128;

elseif (y(i,j) >= (2*r1)) && (y(i,j) < s);

t=y(i,j);

z=t-170;

f=(255/r1)*z;

x(i,j,1)=192;

x(i,j,2)=128;

x(i,j,3)=z;

elseif (y(i,j) >= s) && (y(i,j) < (s+r2));

t=y(i,j);

f=(255/r2)*t;

x(i,j,1)=f;

x(i,j,2)=64;

x(i,j,3)=192;

elseif (y(i,j) >= (s+r2)) && (y(i,j) < (s+2*r2));

t=y(i,j);

z=t-r2;

f=(255/r2)*z;

x(i,j,1)=64;

x(i,j,2)=z;

x(i,j,3)=192;

elseif (y(i,j) >= (s+2*r2)) && (y(i,j) < 255);

t=y(i,j);

z=t-2*r2;

f=(255/r2)*z;

x(i,j,1)=64;

x(i,j,2)=192;

x(i,j,3)=z;

end

end

end

imshow(e);

% subplot(1,2,2);

% image(x);

x=1-x;

figure

% image(x);

imshow(x);

QPSK Signal generation

clc;clear all;close all;

%program to generate qpsk signal

b=input('Enter the bit stream');

ps=1;

w=2*pi*60;

t=0:.126:2*pi;

l=length(b);

for i=1:1:l

if (b(1,i)==0)

bt(1,i)=-1;

else if (b(1,i)==1)

bt(i)=1;

else

error('input bit stream is non binary');

break;

end

end

end

% now we have to form the odd and the even bit stream

s=1;

for i=1:2:l

odd(s)=bt(i);

s=s+1;

end

dd=1;

for j=2:2:l

even(1,dd)=bt(1,j);

dd=dd+1;

end

k=0;

lo=length(odd);

le=length(even);

ls=max(lo,le);

if (le < ls)

even=[even,-1];

end

if (lo < ls)

odd=[odd,-1];

end

lo=length(odd);

le=length(even);

cc=0;

for i=1:1:lo

if (odd(i)==1)

cc=cc+1;

no(cc)=1;

cc=cc+1;

no(cc)=1;

else if (odd(i)==-1)

cc=cc+1;

no(cc)=-1;

cc=cc+1;

no(cc)=-1;

end

end

end

cc=0;

for i=1:1:le

if (even(i)==1)

cc=cc+1;

ne(cc)=1;

cc=cc+1;

ne(cc)=1;

else if (even(i)==-1)

cc=cc+1;

ne(cc)=-1;

cc=cc+1;

ne(cc)=-1;

end

end

end

s1=sqrt(ps)*sin(t);

s0=sqrt(ps)*cos(t);

k=0;

nl=ls*50;

for j=1:1:ls

for i=1:1:50

k=k+1;

v(i)= no(j)*s1(i)+ne(j)*s0(i);

vm(k)=v(i);

end

end

n=1;

tb=0;

for m=1:1:l

for i=1:1:25

tb(n)=bt(m);

odstr(n)= no(m);

evstr(n)= ne(m);

n=n+1;

end

end

n=1;

for m=1:1:ls

for i=1:1:50

odstr(n)= no(m);

evstr(n)= ne(m);

n=n+1;

end

end

subplot(4,1,1);stairs(tb ,'k','LineWidth',2);

title('INPUT BIT STREAM');

% grid on;

subplot(4,1,2);stairs(odstr,'r','LineWidth',2);

title('ODD BIT STREAM');

% grid on;

subplot(4,1,3);stairs(evstr,'g','LineWidth',2);

title('EVEN BIT STREAM');

% grid on;

subplot(4,1,4);plot(vm,'b','LineWidth',2);

title('QPSK WAVEFORM')

%program for qpsk demodulation

aa=input('Enter the quadrant of the qpsk signal(1 for first, 2 for second, 3 for third and 4 for fourth');

ll=length(aa);

for i=1:1:ll

if (aa(1,i)==1)

be(1,i)=(-1);

bo(1,i)=1;

else if (aa(1,i)==2)

be(1,i)=1;

bo(1,i)=1;

else if (aa(1,i)==3)

be(1,i)=1;

bo(1,i)=(-1);

else if (aa(1,i)==4)

be(1,i)=(-1);

bo(1,i)=(-1);

else

error('Quadrant can only have values 1,2,3 and 4')

break;

end

end

end

end

end

ss=length(be);

i=1;j=1;

while (i<ss)

d(j)=bo(1,i);

j=j+1;

d(j)=be(1,i);

i=i+1;

j=j+1;

end

l=length(d);

for k=1:1:l

if d(1,k)==-1

d(1,k)=0;

end

end

figure

subplot(3,1,1);stem(bo);title('Odd bit stream');

subplot(3,1,2);stem(be);title('Even bit stream');

subplot(3,1,3);stem(d);title('Original bit stream');