Question

If unsharp masking can be implemented directly in frequency domain by using a composite filter: Hhp(u, v) = 1 – Hlp(u, v), where Hlp(u, v) the transfer function of a lowpass filter. Then, the composite filter for High-boost filtering is __________

(a) Hhb(u, v) = 1 – Hhp(u, v)

(b) Hhb(u, v) = 1 + Hhp(u, v)

(c) Hhb(u, v) = (A-1) – Hhp(u, v), A is a constant

(d) Hhb(u, v) = (A-1) + Hhp(u, v), A is a constant

This question was addressed to me in exam.

The above asked question is from Unsharp Masking, High-boost filtering and Emphasis Filtering in portion Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

Correct option is (d) Hhb(u, v) = (A-1) + Hhp(u, v), A is a constant

Easiest explanation: For given composite filter of unsharp masking Hhp(u, v) = 1 – Hlp(u, v), the composite filter for High-boost filtering is Hhb(u, v) = (A-1) + Hhp(u, v).