Question

High boost filtered image is expressed as: fhb = A f(x, y) – flp(x, y), where f(x, y) the input image, A is a constant and flp(x, y) is the lowpass filtered version of f(x, y). Which of the following fact(s) validates if A increases past 1?

(a) The contribution of the image itself becomes more dominant

(b) The contribution of the highpass filtered version of image becomes less dominant

(c) All of the mentioned

(d) None of the mentioned

This question was addressed to me during an interview.

I need to ask this question from Unsharp Masking, High-boost filtering and Emphasis Filtering in chapter Intensity Transformations and Spatial Filtering of Digital Image Processing

Answer 1

The correct option is (c) All of the mentioned

The explanation: High boost filtered image is modified as: fhb = (A-1) f(x, y) +f(x, y) – flp(x, y)

i.e.  fhb = (A-1) f(x, y) + fhp(x, y). So, when A>1, the contribution of the image itself becomes more dominant over the highpass filtered version of image.