Question

Which of the following fact(s) is/are true for the relationship between low frequency component of Fourier transform and the rate of change of gray levels?

(a) Moving away from the origin of transform the low frequency corresponds to smooth gray level variation

(b) Moving away from the origin of transform the low frequencies corresponds to abrupt change in gray level

(c) All of the mentioned

(d) None of the mentioned

This question was posed to me during an interview.

This interesting question is from Filtering in Frequency Domain in section Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

Right choice is (c) All of the mentioned

To explain: Moving away from the origin of transform the low frequency corresponds to the slowly varying components in an image. Moving further away from origin the higher frequencies corresponds to faster gray level changes.