Question

Which of the following in an image can be removed by using smoothing filter?

(a) Smooth transitions of gray levels

(b) Smooth transitions of brightness levels

(c) Sharp transitions of gray levels

(d) Sharp transitions of brightness levels

I have been asked this question during an interview.

Asked question is from Smoothing Spatial Filters in section Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

The correct option is (c) Sharp transitions of gray levels

For explanation: Smoothing filter replaces the value of every pixel in an image by the average value of the gray levels. So, this helps in removing the sharp transitions in the gray levels between the pixels. This is done because, random noise typically consists of sharp transitions in gray levels.