labelImages - a small tool to do image labeling in Matlab

labelImages.m

% labelImages(impath)
% ---------------------------------------
% Places labels on an image, and saves the marker locations and a 3x3
% square pixel neighborhood of RGB values.
%
% Usage:
% labelImages('/Users/astorer/Desktop/test.jpg')
% LEFT CLICK  - Add a point
% RIGHT CLICK - Delete a point
% 's'         - Save progress
% 'Esc'       - Save and quit
%
% The following files will be written:
% /Users/astorer/Desktop/test.mat
% /Users/astorer/Desktop/test.csv

function labelImages(impath)
[pathstr, fname, ext] = fileparts(impath);
loadfile = [pathstr filesep fname '.mat'];
try
    load(loadfile)
catch
    disp(['No data present for image ' impath])
    imdat = {};
end

nPts = length(imdat);

imshow(impath)
hold on;
imdat = redraw(imdat);
imdat = getPoints(impath,imdat);

save([pathstr filesep fname '.mat'],'imdat');
writeCSV(impath,imdat)

end

function imdat = getPoints(impath,imdat)
[pathstr, fname, ext] = fileparts(impath);

button = -1;
while (button ~= 27)
    [x,y,button] = ginput(1);
    if button==1
        % left click, add a point
        p = struct;
        p.x = x;
        p.y = y;        
        i = length(imdat)+1;
        p.h2 = plot(x,y,'wo','MarkerSize',5,'MarkerFaceColor','k');
        p.h = plot(x,y,'ko','MarkerSize',4,'MarkerFaceColor',[255 56 255]./256);
        %p.text = text(x+3,y,num2str(length(imdat)+1),'Color','k','FontSize',12,'FontWeight','bold');
        p.text2 = text(x+6,y+3,num2str(i),'Color',[255 56 255]./256,'FontSize',16,'FontWeight','bold');

        imdat{end+1} = p;
    elseif button==115 % s to save
        save([pathstr filesep fname '.mat'],'imdat');
        writeCSV(impath,imdat)
    elseif button==3
        cutoff = 25;
        for i = 1:length(imdat)
            oldx = imdat{i}.x;
            oldy = imdat{i}.y;
            d = sqrt((x - oldx).^2 + (y - oldy).^2);
            %disp(['Distance to point ' num2str(i) ' is ' num2str(d)]);
            if d < cutoff
                disp(['Removing point ' num2str(i)])
                set(imdat{i}.h,'visible','off');
                set(imdat{i}.h2,'visible','off');
                %set(imdat{i}.text,'visible','off');                
                set(imdat{i}.text2,'visible','off');
                                
                
                imdat = remove(imdat,i);
                imdat = redraw(imdat);
                break;
            end
        end
    end
        
end
    
close(gcf)
end

function newc = remove(c,i)
newc = {};
for ind = 1:length(c)
    if (ind<i)
        newc{ind} = c{ind};
    end
    if (ind>i)
        newc{ind-1} = c{ind};
    end
end
end

function imdat = redraw(imdat)
for i = 1:length(imdat)
    try
        set(imdat{i}.h,'visible','off');
    end
    try
        set(imdat{i}.h2,'visible','off');
    end    
    try
        %set(imdat{i}.text,'visible','off');
    end
    try
        set(imdat{i}.text2,'visible','off');
    end
    imdat{i}.h2 = plot(imdat{i}.x,imdat{i}.y,'wo','MarkerSize',5,'MarkerFaceColor','k');
    imdat{i}.h = plot(imdat{i}.x,imdat{i}.y,'ko','MarkerSize',4,'MarkerFaceColor',[255 56 255]./256);
    x = imdat{i}.x;
    y = imdat{i}.y;
    %imdat{i}.text = text(x+3,y,num2str(i),'Color','k','FontSize',16,'FontWeight','bold');
    imdat{i}.text2 = text(x+6,y+3,num2str(i),'Color',[255 56 255]./256,'FontSize',16,'FontWeight','bold');

    end
end

function writeCSV(impath,imdat)
n = 3;
RGB = imread(impath);
[pathstr, fname, ext] = fileparts(impath);
fid = fopen([pathstr filesep fname '.csv'],'w+');
for i = 1:length(imdat)
    x = imdat{i}.x;
    y = imdat{i}.y;
    dat = [i getMeanNbd(x,y,RGB(:,:,1),n) getMeanNbd(x,y,RGB(:,:,2),n) getMeanNbd(x,y,RGB(:,:,3),n)];
    fprintf(fid,'%d, %3.4f , %3.4f, %3.4f\n',dat);
end
fclose(fid);
end

% flip x and y!
function m = getMeanNbd(y,x,mat,nbd)
x = round(x);
y = round(y);
if mod(nbd,2)==0
    error('Please give an odd neighborhood')
end
tot = 0;
for xi = -floor(nbd/2):floor(nbd/2)
    for yi = -floor(nbd/2):floor(nbd/2)
        tot = tot + double(mat(x+xi,y+yi));
    end
end
m = tot/(nbd*nbd); % e.g., a 3x3 nbd
end