Convex hull

[momina]

I have to do the convex hull of an image A using following structuring elements
B1=[ 1 0 0; 1 0 0; 1 0 0];B2=[1 1 1 ;0 0 0; 0 0 0]
When at first step i an finding the hit and miss transform with B1 then i have a confusion that with which i take erosion of A complement.

[snibgo]

I don't understand the question.

One method for finding convex hulls is explained at http://www.imagemagick.org/Usage/morphology/#convexhull