Question

Which of the following a transfer function of High frequency emphasis {Hhfe(u, v)} for Hhp(u, v) being the highpass filtered version of image?

(a) Hhfe(u, v) = 1 – Hhp(u, v)

(b) Hhfe(u, v) = a – Hhp(u, v), a≥0

(c) Hhfe(u, v) = 1 – b Hhp(u, v), a≥0 and b>a

(d) Hhfe(u, v) = a + b Hhp(u, v), a≥0 and b>a

I have been asked this question during an interview.

This question is from Unsharp Masking, High-boost filtering and Emphasis Filtering topic in section Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

Right answer is (d) Hhfe(u, v) = a + b Hhp(u, v), a≥0 and b>a

The best I can explain: The transfer function of High frequency emphasis is given as:Hhfe(u, v) = a + b Hhp(u, v), a≥0 and b>a.