Matlab notes for image project

% The imread command in Matlab is often useful for importing files such as
% tiff, bmp, or jpg.
% You may need to convert the data to type double after loading it.
% For example:

imfinfo('house.bmp') % gives information about image

% If the ColorType is 'indexed', one need to read the image and colormap,

[house,map]=imread('house.bmp','bmp');

figure; image(house);colormap(map)

%% then convert it using ind2rgb or ind2gray :
hg=ind2gray(house,map);

%% use imshow or imagesc to show it:
figure; imshow(hg)
figure; imagesc(hg); colormap(gray)

%% now can work with the file as with regular data file, for example:
hgg=hg.*hg; figure; imagesc(hgg); colormap(gray)


% Another example for truecolor image:
imfinfo('boat.bmp') % gives information about image

boat=imread('boat.bmp');
image(boat) % can use image, imagesc, imshow to see it

size(boat) % gives file size - 200 x 200 x 3 in this case

% because this is a truecolor image, take the first
% component only (do not do that if your ColorType is 'indexed'):
b1 = boat(:,:,1);
% or use rgb2gray - it creates a grayscale intensity image from an RGB image:
boat=rgb2gray(boat);



% If you used rgb2gray or ind2gray to create a grayscale image file,
% your data type is double, if not -
% you may need to convert the file to double type:
b1 = double(b1);
% since MATLAB arithmetic operators cannot accept uint8 or uint16 data
%

% can use imagesc to see the image
figure; imagesc(b1); colormap(gray);
figure; image(b1,'CDataMapping','scaled'); colormap(gray);

% now can work work with the file as with normal data file
% for instance, square its elements:

b_try=b1.*b1; figure; colormap(gray); imagesc(b_try)
%%