BBHE & DSIHE Algorithms, Apply on PSNR filter.

Apply the following Algorithms on 2 different input images

• Brightness Preserving Bi-Histogram Equalization (BBHE)

• Dualistic Sub Image Histogram Equalization (DSIHE).

Finally, apply the PSNR and compute the results for both histograms in tabular form

[Keerthivasan Manavalan]

Hi I would like to utilize these codes in a survey paper on dark image enhancement Would it be okay if i can cite you and use the same

[Azib Zaheer]

yes its okay

Answer 1

[Azib Zaheer]

Code:

%% Obtain the original image
input_image = imread('abc.jpg');

%% Get histogram of the original image
figure(1)
subplot(3,3,1)
imshow(input_image);
title('ORIGINAL IMAGE')
subplot(3,3,2)
imhist(input_image);

%% BBHE 
%% Calculate mean of the histogram
bbhe_mean = round(mean(input_image(:)));

%% Divide the histogram on the basis of the mean in two parts
[H, ~] = imhist(input_image);
H1 = H(1:bbhe_mean);
H2 = H(bbhe_mean+1:256);

%% Equalize each part independently 
H1 = H1/sum(H1);
H2 = H2/sum(H2);

%% Combine both sub-images for the processed image
C1 = cumsum(H1);
C2 = cumsum(H2);

C1n = uint8(bbhe_mean * C1);
C2n = uint8(bbhe_mean+1 + (255-bbhe_mean+1)*C2);
img_sum1 = [C1n; C2n];

%% output image of BBHE
figure(1)
subplot(3,3,4)
imshow(intlut(input_image,img_sum1));
title("BBHE IMG")
subplot(3,3,5)
imhist(intlut(input_image,img_sum1));

%% DSIHE 
%% Obtain the original image
[X, Y] = size(input_image);

%% Get histogram of the original image
[H, ~] = imhist(input_image);

%% Calculate median of the histogram. 
[value, lm] = min (abs(H-(X*Y/2)));

%% Divide the histogram on the basis of the median in two parts.
H1 = H(1:lm);
H2 = H(lm+1:256);

%% Equalize each part independently
H1 = H1/sum(H1);
H2 = H2/sum(H2);

%% Combine both sub-images for the processed image
C1 = cumsum(H1);
C2 = cumsum(H2);

C1n = uint8(lm * C1);
C2n = uint8(lm+1 + (255-lm+1)*C2);
img_sum2 = [C1n; C2n];

%% output image of DSIHE
figure(1)
subplot(3,3,7)
imshow(intlut(input_image,img_sum2));
title("DSIHE IMG")
subplot(3,3,8)
imhist(intlut(input_image,img_sum2));

%% PSNR code
%% For BBHE
P1= psnr(intlut(input_image,img_sum1),input_image); 
%% For DSIHE
P2= psnr(intlut(input_image,img_sum2),input_image); 
%% Display Results
disp(P1);
disp(P2);
figure(1)
subplot(3,3,6)
title("PSNR= ",P1)
subplot(3,3,9)
title("PSNR= ",P2)