imsplit.m

彩色图像纹理提取的一种算法

function objs = imsplit( img, lightback, do_rot, thresh )

% Image Split, (Adam Meadows: [e-mail])
% objs = imsplit( img, lightback, do_rot, thresh )
% 
% IMG is the input image
% LIGHTBACK is a flag specifying that the background is lighter than the foreground
% DO_ROT is a flag to enable/disable rotation of the split images to "face"
% same way
% THRESH is a threshold to use when creating BW image (if 0, automatic)
%
% OBJS returns a cell array containing the individual images for each obj
%

%RGB = imread(filename);
RGB = img;

I = rgb2gray(RGB);
if thresh == 0
    thresh = graythresh(I);
end

bw = im2bw(I,thresh);

%if the background is light, swap the bw image
if(lightback == 1)
        bw = swap(bw);
end

% remove all object containing fewer than 30 pixels
bw = bwareaopen(bw,30);

% fill any holes, so that regionprops can be used to estimate
% the area enclosed by each of the boundaries
bw = imfill(bw,'holes');

%find background color
background = imbackground(img, lightback);
r = background(1,1,1);
g = background(1,1,2);
b = background(1,1,3);

%[B,L] = bwboundaries(bw,'noholes');
bwl = bwlabel(bw);
bbs = regionprops(bwl, 'BoundingBox');
os = regionprops(bwl, 'Orientation');
cent = regionprops(bwl, 'Centroid');
dims = size(img);
for k = 1:length(bbs)
    
    %crop it (leaving a 5 pixel border so that the shape can be extracted)
    newBB = bbs(k).BoundingBox;
    newBB = [newBB(1)-5, newBB(2)-5, newBB(3)+10, newBB(4)+10];
    
    %make sure it's just this object
    myBW = bwselect(bw, cent(k).Centroid(1), cent(k).Centroid(2));
    myRGB = RGB;
    myRGB(:,:,1) = immultiply(RGB(:,:,1), myBW);
    myRGB(:,:,2) = immultiply(RGB(:,:,2), myBW);
    myRGB(:,:,3) = immultiply(RGB(:,:,3), myBW);
    
    cropped = imcrop(myRGB, newBB);
    
   %cropped = imcrop(RGB,newBB);
    
    if do_rot
        %rotate it so that major axis is parallel with image's major axis

        rotangle = 180 - os(k).Orientation;

        usey = 0;
        if(dims(1) > dims(2))
            rotangle = rotangle + 90;
            usey = 1;
        end
        cropped = imrotate(cropped, rotangle);
        csize = size(cropped);
        for i=1:csize(1)
            for j=1:csize(2)
                if(cropped(i,j,:) == 0)
                    cropped(i,j,:) = [ r g b ];
                end;
            end;
        end;

        %now, re-crop it
        Ic = rgb2gray(cropped);
        %threshc = graythresh(Ic);
        bwc = im2bw(Ic,thresh);
        
        %if the background is light, swap the bw image
        if(lightback == 1)
            bwc = swap(bwc);
        end
        bwcl = bwlabel(bwc);
        bbsc = regionprops(bwcl, 'BoundingBox');
        centc = regionprops(bwcl, 'Centroid');
        newCent = centc(1).Centroid;
        newBBc = bbsc(1).BoundingBox;
        newBBc = [newBBc(1)-5, newBBc(2)-5, newBBc(3)+10, newBBc(4)+10];

        cropped = imcrop(cropped, newBBc);

        %see if it's better the other way
        if usey
            if newCent(2)-newBBc(2) < newBBc(4)/2 %Y values upside down
                cropped = imrotate(cropped, 180);
            end
        else
            if newCent(1)-newBBc(1) > newBBc(3)/2
                cropped = imrotate(cropped,180);
            end
        end
    
    else
        csize = size(cropped);
        for i=1:csize(1)
            for j=1:csize(2)
                if(cropped(i,j,:) == 0)
                    cropped(i,j,:) = [ r g b ];
                end;
            end;
        end;
    
    end %end of if do_rot
    
    objs{k} = cropped;
    
end %of function