Question

The transformation s = T(r) producing a gray level s for each pixel value r of input image. Then, if the T(r) is satisfying 0 ≤ T(r) ≤ 1 in interval 0 ≤ r ≤ 1, what does it signifies?

(a) It guarantees the existence of inverse transformation

(b) It is needed to restrict producing of some inverted gray levels in output

(c) It guarantees that the output gray level and the input gray level will be in same range

(d) All of the mentioned

The question was asked during an interview.

I'm obligated to ask this question of Histogram Equalization and Processing in section Image Enhancement of Digital Image Processing

Answer 1

Correct choice is (c) It guarantees that the output gray level and the input gray level will be in same range

Easy explanation: If, 0 ≤ T(r) ≤ 1 in interval 0 ≤ r ≤ 1, then the output gray level and the input gray level will be in same range.