edge detection - "falling drop"

Hey, S.O.S. I need help :)

I have to do program in matlab of edge detection in picture - namely edge detection of bone ... not with Sobel, Canny etc., it has to be method of falling drop (translate from czech language)

I have vertical detection:

x=imread('k00003.jpg');
im=rgb2gray(x);
im=im2double(im);
[q,r]=size(im);
prah = 0.55;
YY=zeros(1,r);
XX=1:r;
for i=1:r;
    for j=25:q;
        if im(j,i) >= prah
            YY(i)=j;
            break             
        end         
    end
end

BUT now I need diagonal detection (my professor said me to use vector). But I am really bad in Matlab. So please can somebody help me?

Thanks

[Image Analyst]

We can't help until we know what you want to do. I have not heard of the Czech falling drop method, and all you're doing is creating a binary image of the bottom portion of the image - there's no edge detection whatsoever. And why do you need edge detection? Can you attach your image so we can see it? Maybe simple thresholding is all you need. Why do you think you need that particular method to segment your object? And why are you only doing it on row 25 and below?