Back to: Image Processing

Image Enhancement

 

A) Threshold Of An Image
B) Contrast Stretching Of An Image
C) Brightness Adjustment of an Image Circle
D) Gray Level Slicing

(A) Threshold Of An Image

Code:-

clear all;
clc;
close all;
a=imread(‘grayscale.jpg’);
a=double(a);
b=a;
[row col]=size(a);
T=input('Enter Threshold value: - ');
for x=1:1:row
               for y=1:1:col
                        if a(x, y)<=T
                        b(x, y)=0;
                        else b(x, y)=255;
                        end
                end
end
subplot(2,2,1)
imshow(uint8(a));
title('Original Image')
subplot(2,2,2)
imshow(uint8(b));
title ('Thresholded Image');

 

Output For Thresholding

 

 

 

 

 

 

 
 

 

 

 

 

 (B)Contrast Stretching Of An Image

Code:-

clear all;
clc;
close all;
a=imread('D:\final print\dip speech\images1.jpg');
a=double(a);
b=a
[row col]=size(a);
r1=input('Enter Lower value: - ');
r2=input('Enter Upper value: - ');
A=input('Enter Slope 1 : - ');
B=input('Enter Slope 2 : - ');
C=input('Enter slope 3 : - ');
s1=A*r1;
s2=B*(r2-r1)+s1;
for x=1:1:row
               for y=1:1:col
                        if a(x,y)<r1
                            b(x,y)=s1;
                        elseif  a(x,y)>r1 &&  a(x,y)<r2
                        b(x,y)=B*(a(x,y)-r1)+s1;
                        else b(x,y)=C*(a(x,y)-r2)+s2;
                        end
                end
end
subplot(2,2,1)
imshow(uint8(a));
title('Original Image')
subplot(2,2,2)
imshow(uint8(b));
title ('Contrast Stretched');

Output For Contrast Stretching

(C)Brightness Adjustment of an Image

Code:-

clear all;
clc;
close all;
a=imread('D:\final print\dip speech\images2.jpg');
a=double((a));
b=a
[row col]=size(a);
bt=input('Enter level of brightness to increase: ');
for x=1:row
               for y=1:col
                        b(x,y)=a(x,y)+bt;
                end
end
subplot(1,2,1)
imshow(uint8(a));
title('Original Image')
subplot(1,2,2)
imshow(uint8(b));
title ('Brightness Adjusted image');

Output Of An Brightness Adjustment

(D) Gray Level Slicing

Code:-

clear all;
clc;
close all;
a=imread('D:\final print\dip speech\images3jpg');
b=a
[row col]=size(a);
r1=input('enter range 1: ');
r2=input('enter range 2: ');
for x=1:row
               for y=1:col
                        if a(x,y)>=r1 && a(x,y)<=r2
                            b(x,y)=255;
                            c(x,y)=255;
                        else
                            b(x,y)=a(x,y);
                            c(x,y)=0;
                        end
                end
end
subplot(3,3,1)
imshow(uint8(a));
title('Original Image')
subplot(3,3,2)
imshow(uint8(b));
title('Gray sliced image with background');
subplot(3,3,3)
imshow(uint8(c));
title('Gray sliced image without background');

Output Of An Gray Level Slicing