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% manipulating images - demo part 1 - useful for HW4
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% read in an image
img = (imread('2904052434_762e80bb2d_o.jpg'));
size(img)

% show the image
imagesc(img);
% get some coordinates from the image
[x,y] = ginput(2);
% x coords of input
x
% y coords of input
y

% make them integers
x = round(x);
y = round(y);

% get out a small subimage
subimg = img(y(1):y(2),x(1):x(2),:);
imagesc(subimg)
axis equal

% set that part to black
newimg = img;
for i=y(1):y(2)
	for j=x(1):x(2)
		newimg(i,j,:) = [0 0 0];
	end
end

imagesc(newimg);

% or replace it with another img
img2 = (imread('flower.jpg'));
imagesc(img2);
size(img2)

% resize img2 so it fits in the hole we have made
img2 = imresize(img2,[y(2)-y(1)+1,x(2)-x(1)+1]);
newimg(y(1):y(2),x(1):x(2),:) = img2;

newimg(find(newimg<0))=0;


imagesc(newimg);


img2 = (imread('flower.jpg'));
[m,n,c] = size(img2);
img2 = imresize(img2,.2);
[m,n,c] = size(img2);

newimg2 = img;
newimg2(1:m,1:n,:) = img2;

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% pixel representation - demo part 2
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img = (imread('2904052434_762e80bb2d_o.jpg'));
img1 = img(1:end,50:end,:);
img2 = img(1:end,1:end-49,:);
imagesc(img1);
figure; imagesc(img2);

% unshifted similarity average value diff
sim1 = sum(sum(sum(abs(img-img))))/(size(img,1)*size(img,2)*size(img,3));

% shifted similarity - average value diff - large!
sim2 = sum(sum(sum(abs(img1-img2))))/(size(img,1)*size(img,2)*size(img,3));

close all

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% color representation - demo part 3
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img = (imread('2046794090_5b3c0c9cc1_o.jpg'));
% reads in as uint8, convert to doubles
img = (img);
imagesc(img);

% average color
sumcolor = [0 0 0];
for i=1:size(img,1)
	for j=1:size(img,2)
		sumcolor = sumcolor+reshape(img(i,j,:),[1 3]);
	end
end
avecolor = sumcolor/(size(img,1)*size(img,2));
% let's look at it by putting it into a 10x10 image
avecolorimg = zeros(10,10,3);
for i=1:10
	for j=1:10
		avecolorimg(i,j,:) = avecolor;
	end
end
figure; imagesc(avecolorimg);

% spatial grid of average colors
newimg = zeros(size(img));
% break image up into 50x50 pixel regions
for i=1:50:size(img,1)
	stopi = min(i+49,size(img,1));
	for j=1:50:size(img,2)
		% calculate average color in each of the regions
		stopj = min(j+49,size(img,2));
		avecolorr = mean(mean(img(i:stopi,j:stopj,1)));
		avecolorg = mean(mean(img(i:stopi,j:stopj,2)));
		avecolorb = mean(mean(img(i:stopi,j:stopj,3)));
		newimg(i:stopi,j:stopj,1) = avecolorr;
		newimg(i:stopi,j:stopj,2) = avecolorg;
		newimg(i:stopi,j:stopj,3) = avecolorb;
	end
end
imagesc(newimg);
		
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% edges - demo part 4
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img1 = (imread('redumbrella.jpg'));
img2 = (imread('grayumbrella2.jpg'));

imagesc(img1);
figure; imagesc(img2);
BW1 = rgb2gray(img1);
size(BW1);
BW2 = rgb2gray(img2);
size(BW2);
figure(1); imagesc(BW1);
colormap gray
figure(2); imagesc(BW2);
colormap gray

filtx = [1 1 1; 0 0 0; -1 -1 -1];
%[-1; 0; 1];
filty = [-1 0 1; -1 0 1; -1 0 1];
%[-1 0 1];

% convolve img1 with filter 
Gx1 = conv2(BW1,filtx,'same');
Gy1 = conv2(BW1,filty,'same');

figure(1); imagesc(abs(Gx1))
colormap gray
figure(2); imagesc(abs(Gy1))
colormap gray

% convolve img2 with filter 
Gx2 = conv2(BW2,filtx,'same');
Gy2 = conv2(BW2,filty,'same');

figure(3); imagesc(abs(Gx2))
colormap gray
figure(4); imagesc(abs(Gy2))
colormap gray

% edge map
edges1 = abs(Gx1+Gy1);
edges2 = abs(Gx2+Gy2);
figure(1); imagesc(edges1);
figure(2); imagesc(edges2);

imagesc(edges1+edges2);

% edges close but not completely aligned. 
% allow for some variation in position by using a spatial grid

% spatial grid of edge energy
edgeenergy1 = zeros(ceil(size(edges1,1)/50),ceil(size(edges1,2)/50));
edgeenergy2 = zeros(ceil(size(edges2,1)/50),ceil(size(edges2,2)/50));
% break image up into 50x50 pixel regions
icount=0; jcount=0;
for i=1:50:size(edges1,1)
	icount=icount+1;
	stopi = min(i+49,size(edges1,1));
	jcount=0;
	for j=1:50:size(edges1,2)
		jcount=jcount+1;
		% calculate average color in each of the regions
		stopj = min(j+49,size(edges1,2));
		edgeenergy1(icount,jcount) = sum(sum(edges1(i:stopi,j:stopj)));
		edgeenergy2(icount,jcount) = sum(sum(edges2(i:stopi,j:stopj)));
	end
end

edgeenergy1 = edgeenergy1/sum(edgeenergy1(:));
edgeenergy2 = edgeenergy2/sum(edgeenergy2(:));

close all
imagesc(edgeenergy1); 
figure; imagesc(edgeenergy2); 

sim = sum(sum(abs(edgeenergy1-edgeenergy2)))/(size(edgeenergy1,1)*size(edgeenergy2,2));