A Registration Method Based on Contour Point Cloud for 3D Whole-Body PET and CT Images

Algorithm 2

Dynamic threshold segmentation.

Input: The result image of median filter S and the id of the current slice.

Output: The result of threshold segmentation T, which is a binary image.

Steps:

() H = calcHist (S)       Calculating the gray histogram of S.

() peakLoc = getPeakLoc (H);   peakLoc is the gray value corresponding to the peak

() if id < 36 then threshold = peakLoc + 1

() else if id < 46

(5)  if peakLoc > 5 then threshold = peakLoc + 3

    else if peakLoc > 3 then threshold = peakLoc − 3

    else threshold = 0

    end if

(6) else threshold = peakLoc + 3

(7) end if

(8) T = doThreshold (S, threshold)