Question

In neighborhood operation for spatial filtering if a square mask of size n*n is used it is restricted that the center of mask must be at a distance ≥ (n – 1)/2 pixels from border of image, what happens to the resultant image?

(a) The resultant image will be of same size as original image

(b) The resultant image will be a little larger size than original image

(c) The resultant image will be a little smaller size than original image

(d) None of the mentioned

The question was posed to me in an internship interview.

The origin of the question is Spatial Filtering topic in division Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

Correct answer is (c) The resultant image will be a little smaller size than original image

Explanation: If the center of mask must be at a distance ≥ (n – 1)/2 pixels from border of image, the border pixels won’t get processed under mask and so the resultant image would be of smaller size.