% image_adjust is a program that allows images
% such as 'jpg', 'gif', 'bmp' etc to be adjusted
% in terms of numerical data.
%   Adjustment is done by either increaseing the 
% green and blue components by addition, or by 
% exponential compression.
%   USE: Change the file name, type, folder below
% to the images you are interested in working on.
%
% run image_adjust
%
% Last Edit by Colin Joye, 10/2/03
clear all;
%-------------- USER INPUT -----------------------
% location of folder. =[] is \work folder.
%folder = 'C:\Documents and Settings\Colin Joye\My Documents\AES_115th\images\';
folder = 'C:\Documents and Settings\Colin Joye\Desktop\';

% file type can be 'jpg', 'gif', 'tiff', 'bmp', etc.
file_type = 'jpg';

% name of current file to be modified.
in_file_name = 'photo5';

% name of new adjusted file to be saved.
out_file_name = 'photo5_adj'; 

% Red, Green and Blue level adjust: adds number specified to numerical 
% image data, which ranges from 0 to 255 in integers.
red = -20;
grn = -20;
blu = -20;

% COMP factor introduces compression to the image by raising the data to 
% an exponential factor. comp==1.0 means no compression.  Using a little 
% compression tends to remove haze from the image and increase contrast.
comp = 1.02;

% Image rotation angle to correct tilted images [degrees CCW]
phi  = 0; 

%-------------- END USER INPUT -----------------------

A = imread([folder in_file_name],file_type); % read image, store as "uint8" type
B = double(A); % convert "uint8" to "double" for math

[Lr Lc Lz] = size(B);
base = ones(Lr, Lc);

adj = cat(3, red*base, grn*base, blu*base);

% Color adjust method:
C = B.^comp + adj;

% BW high contrast method:
%C = 220*(B>233)+35;

% rotate image:
C = imrotate(C,phi,'bilinear','crop');

D = uint8(C); % convert back to "uint8" to save
imwrite(D,[folder out_file_name '.' file_type],file_type); % save with new filename

% show the change:
figure(1)
clf(1)
subplot(121)
image(A);
axis image;
title(['Original: ' in_file_name '.' file_type],'Interpreter','none');
subplot(122)
image(D);
axis image;
title(['Altered: ' out_file_name '.' file_type],'Interpreter','none');
% ------------------ END image_adjust.m ----------------------------