Halftoning an image results in three replicas. Why?

Hello! I have used the following code to create a halftoned image. Why does the original image get replicated thrice as shown in the attached image. Thanks in advance.

%Program for Image Halftoning by Floyd Method

%Program Description % The input gray image will be converted into halftone image % of same size using Floyd's Error Diffusion Method. % %Parameters % inImg - Input Gray Image % outImg - Output Halftoned Image

function outImg = floydHalftone(inImg) inImg = double(inImg);

[M,N] = size(inImg); T = 127.5; %Threshold y = inImg; error = 0;

for rows = 1:M-1

    %Left Boundary of Image
    outImg(rows,1) =255*(y(rows,1)>=T);
    error = -outImg(rows,1) + y(rows,1);
    y(rows,1+1) = 7/16 * error + y(rows,1+1);
    y(rows+1,1+1) = 1/16 * error + y(rows+1,1+1);
    y(rows+1,1) = 5/16 * error + y(rows+1,1);

    for cols = 2:N-1
        %Center of Image
        outImg(rows,cols) =255*(y(rows,cols)>=T);
        error = -outImg(rows,cols) + y(rows,cols);
        y(rows,cols+1) = 7/16 * error + y(rows,cols+1);
        y(rows+1,cols+1) = 1/16 * error + y(rows+1,cols+1);
        y(rows+1,cols) = 5/16 * error + y(rows+1,cols);
        y(rows+1,cols-1) = 3/16 * error + y(rows+1,cols-1);
    end

    %Right Boundary of Image
    outImg(rows,N) =255*(y(rows,N)>=T);
    error = -outImg(rows,N) + y(rows,N);
    y(rows+1,N) = 5/16 * error + y(rows+1,N);
    y(rows+1,N-1) = 3/16 * error + y(rows+1,N-1);

end

%Bottom & Left Boundary of Image rows = M; outImg(rows,1) =255*(y(rows,1)>=T); error = -outImg(rows,1) + y(rows,1); y(rows,1+1) = 7/16 * error + y(rows,1+1);

%Bottom & Center of Image for cols = 2:N-1 outImg(rows,cols) =255*(y(rows,cols)>=T); error = -outImg(rows,cols) + y(rows,cols); y(rows,cols+1) = 7/16 * error + y(rows,cols+1); end

%Thresholding outImg(rows,N) =255*(y(rows,N)>=T);

outImg = im2bw(uint8(outImg));

if true
  % code
end

Answer 1

[Image Analyst]

Probably because it's a color image and you're using this line of code:

[M,N] = size(inImg);

which assumes a monochrome image. Please read Steve's blog: http://blogs.mathworks.com/steve/2011/03/22/too-much-information-about-the-size-function/

Then change the code to:

[M,N, numberOfColorChannels] = size(inImg);

Then give it a try.

[dsr]

Thanks a ton for the help. It worked !!!!!

[Image Analyst]

Can you mark the Answer as Accepted then?