Activity 8: Morphological Operations

Objective: To demonstrate the concepts of image dilation and erosion via a structuring element.

Tools: Scilab with SIP toolbox

Procedure: We use an image set as shown below. The square is 50 by 50 pixels while the hollow square is 60 by 60 and 4 pixels in width. The traingle is 30 by 50 while the circle is 25 pixels in radius. On the other hand, the cross is 8 pixels wide and each arm is 50 pixels long.

ORIGINAL

We use the following structuring elements:

SE1=

1 1 1 1

1 1 1 1

1 1 1 1
DILATION AND EROSION USING SE 1

SE2=

1 1 1 1

1 1 1 1

DILATION AND EROSION USING SE 2

SE3=

1 1

1 1

1 1

1 1

DILATION AND EROSION USING SE 3

SE4=

0 0 1 0 0

0 0 1 0 0

1 1 1 1 1

0 0 1 0 0

0 0 1 0 0

DILATION AND EROSION USING SE 4

We notice distinct changes in the images (which incidentally do not correspond to the predictions made previously). Using a square SE we simply see a transfromation of the structure either as an expansion of the lines in case of dilation and compression with erosion. For the non-symmetric elements( like the 2x4 and 4x2 ones), the expansion or contraction only applies to the elements parallel to the longitudinal axis of the SE. On the other hand, the cross SE yields transformations on both axes as well as the characteristic edge rounding of small SEs.

Acknowledgements: I would like to thank Mr. Cabello and Mr. Panganiban for their assistance.

Evaluation: Since the predictions do not match the result only a grade of 8 is seen as appropriate.