MIE-NSCT: Adaptive MRI Enhancement Based on Nonsubsampled Contourlet Transform

Algorithm 1

Steps for low-pass sub-band enhancement.

(i)	Step 1. Valley segment: If , is a valley point. Calculate the position of the segment point and divide the histogram into .
(ii)	Step 2. Change between segments: Whilst , if ,  = . Otherwise, proceed to step 3.
(iii)	Step 3. Change between segments: Whilst , if ,  = . Otherwise, proceed to step 4.
(iv)	Step 4. Intrasegment transformation: Assuming the length of the segment is , whilst , . Otherwise, turn .