CC analysis: based on bad-data first (thresholding not robust)

Problem

1. thresholding not robust, a overly hi-thresh tends to bring top-edges to the ground -> bottom.

Solution

1. find bad data (Inf) first, what's inside of it are bottoms, the rest of the FOV are tops.

Imp

1. good data <= 1, bad <=0,
   
2. CC analysis, 
3. get bad-contained CCs -> bottom