I want explanation for this code GIVEN BELOW ?

clc;
clear all;
close all;
I1=imread('nature1.jpg','jpg');
figure(1);imshow(I1,[]);title('gray image');

%set(gcf, 'Position', get(0,'Screensize')); % Maximize figure. 

%I=genpath;
%P=imread('I');
figure(2);imhist(I1);title('HISTOGRAM OF GRAY IMAGE');
%zpoint(I,ADJ );
I2=imread('nature2.jpg','jpg');
%figure
%set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.
figure(3);imshow(I2);title('COLOUR IMAGE');
I2conv=rgb2gray(I2);
imhist(I2conv);title('HISTOGRAM OF COLOR IMAGE')
%%check number of channels
if size(I1, 3) ~= 1
I1 = rgb2gray(I1);
I1=wiener2(I1,[5 5]);
figure(4);imshow(I1);title('a');
end
if size(I2, 3) ~= 3
error('img2 must be a color image (not indexed)');
end

%%convert to ycbcr
Y1 = rgb2ycbcr(I1(:, :, [1 1 1]));
Y2 = rgb2ycbcr(I2);

%%normalize
Y1d = double(Y1(:, :, 1));
Y2d = double(Y2(:, :, 1));
Y2n = Y2d(:) /(1 - range(Y2d(:)) / 255) * (1 - range(Y1d(:)) / 255);
Y1n = Y1d(:) /(1 - range(Y2d(:)) / 255) * (1 - range(Y1d(:)) / 255);

%%build luminancetransform
BLT = zeros(256, 1);
for y1 = 0 : 255
[val, idx] = min(abs(Y2n - Y1n(1:24300)));
BLT(y1 + 1) = idx(1);
end

%%compare luminance
idx = BLT(Y1d + 1);
Y2_2 = Y2(:, :, 2);
Y2_3 = Y2(:, :, 3);
nimage = cat(3, Y1(:, :, 1), Y2_2(idx), Y2_3(idx));
rgb = uint8(ycbcr2rgb(nimage));

I3=imhistmatch(rgb,I2);
%I3=histeq(I2,256);
figure(6);imshow(I3);title('FINAL IMAGE');
set(gcf, 'Position', get(0,'Screensize')); % Maximize figure.

[Martin Schätz]

Hi, can you format your code? I don't understand what is commented there and what is code.

[John D'Errico]

No. Sorry, but be serious.

This is a large piece of code, not just a tiny fragment. To ask what the entire mess does, in detail would take days to write, depending on how little or much you understand of MATLAB. This could take a MATLAB text as well as basic color and imaging science texts to explain fully.

So if you have not a clue as to what any of the code does, then DO SOME READING. Why are you wanting to understand code that is a complete black box to you anyway?

Once you spend some time reading the code yourself, then feel free to ask a specific question about the code, about ONE piece of it.