Morphologycal-edge-detection-using-erosion-and-dialation

the task is to detect object boundary using erosion or dialation .
Here, use the kernel or structure element such as 3x3
1 1 1
1 1 1
1 1 1

if initial binary image is A and after erosion we get B
then , boundary = A - B

for dialation ,
boundary = B - A

input image

erosion output

boundary detection from erosion

dialation output

boundary detection from dialation