imdilate in octave shows error

[preethi k]

hi all,

I am new to octave. Using imdilate function shows the following error.

error: imdilate: image and structuring element must have the same class

error: called from:

error: /usr/share/octave/packages/3.2/image-1.0.15/imdilate.m at line 36, col

umn 5

The program i executed is given below.

a=imread('/home/preethi/diplab/Images/morph1.bmp');

%c=gray2ind(a);

%d=gray2ind(a);

b=[1 1 1;1 1 1;1 1 1];

a1=imdilate(a,b);

a2=imerode(a,b);

imshow(a),title('original image');

figure,imshow(a1),title('Dilated image');

figure,imshow(a2),title('erode omage');

Please help me.

--Preethi