Laplacian edge operator

i coded up Laplacian edge operator using MFC c++ .. now i want to varify the result using matlab..

 Laplacian Operator and Campass Gradient Operator: result is given below website: http://imm.io/626r

I used Prewitt for Compass Gradeint Operator ... How can i apply this in matlab ?

how can i apply laplacian operator in maltab.. is there any function for that ? i need a sample or example for laplacian operator in matlab.. any one can help me please ?

Thanks in Advace

Answer 1

[David Young]

I assume that the mask you applied in C++ was

 0 -1  0
-1  4 -1
 0 -1  0

and not what you gave in your comment to Oleg's reply.

If that's the case, then all you'd need to do in Matlab is to call the conv2 function, something like this:

mask = [0 -1 0; -1 4 -1; 0 -1 0];
result = conv2(image, mask);

You may need to select the right option for what to do at the boundaries of the image, to match what you did in C++.

[Tina]

hmm i see ok thanks .. let me try now ..

[Tina]

but sir David my result is not same as matlab result.. strange..

[Tina]

Are you there Sir David ? Can you please guide me...

I applied the above matlab statement but my result is not same as matlab ..

[David Young]

You will need to show the results so I can see what the difference is. I suggest you apply both your C++ code and Matlab code to a very small array, and show the input and the results here.

Answer 2

[Oleg Komarov]

Are you referring to discrete laplacian?

[Tina]

I applied this mask :

0 -4 0

-1 4 -1

0 -1 0

for laplacian in c++

Answer 3

[Harsha Vardhan Rao Avunoori]

If you are interested in applying a Laplacian mask to determine the edges then you can try this

BW = edge( I,'log');

where I is your input image you can also search for edge in your MATLAB Help

[David Young]

This also does zero-crossing detection, so you can't compare the results directly to your C++ code.