Question

The requirements of the First Derivative of a digital function:

(a) Must be zero in areas of constant intensity

(b) Must be non-zero at the onset of an intensity step

(c) Must be non-zero along ramps

(d) All of the Mentioned

The question was posed to me in an interview for internship.

My question is taken from Sharpening Spatial Filters topic in section Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

Right answer is (d) All of the Mentioned

The best explanation: All the three conditions must be satisfied.