The contrast Stretching Tx function increases the dynamic range of modified image.

It is defined as S= T(r)

Where T is contrast Stretching Tx function such that,

$$S=\begin{bmatrix} αr&0 ≤ r ≤ a \\S_1+β(r-a)&a \lt r ≤ b \\ S_2+γ(r-b)&b \lt r ≤ L-1 \end{bmatrix}$$

Thresholding Transformation function is defined …