Find the edge of an image

I wanted to find the edge in an palm image .when i use edge command i am able to get the edge but the output is in binary form. Is there any command to show the same edge representation in my original gray image?

Answer 1

[David Sanchez]

There is shorter way to do this, but the idea is this:

[rows cols] = size(I);
nI = zeros(rows,cols);
for row = 1:rows
    for col = 1:cols
            nI(row,col) = I(row,col)*double(BW(row,col));
    end
end
imagescc(nI);

where I is your palm image and BW the image returned by edge and nI the image containing the edges with pixel values (gray scale values in your case) instead of ones

[Sharen H]

When i do this the values present in nI is also binary and not gray ...Please help

Answer 2

[David Sanchez]

Are you sure you are assigning matrices correctly? Try this out. In this case, I is an image in matlab database. nI can not be binary since neither I nor double(BW) are.

I = imread('circuit.tif');
BW = edge(I,'prewitt');

[rows cols] = size(I);
nI = zeros(rows,cols);
for row = 1:rows
    for col = 1:cols
            nI(row,col) = I(row,col)*double(BW(row,col));
    end
end
imagesc(nI);

>> whos
Name        Size              Bytes  Class      Attributes

BW        280x272             76160  logical              
I         280x272             76160  uint8                
col         1x1                   8  double               
cols        1x1                   8  double               
nI        280x272            609280  double               
row         1x1                   8  double               
rows        1x1                   8  double