如何訂購opencv connectedComponentewithStat按地區？

Question

從this問題與下面的代碼。有沒有一種方法可以指定按照最大面積順序返回標籤的功能？如果不是，如果stats已被轉換爲numpy數組，那麼獲得元素索引的最佳方法是什麼（從最大區域到最小區域）？

# Import the cv2 library 
import cv2 
# Read the image you want connected components of 
src = cv2.imread('/directorypath/image.bmp') 
# Threshold it so it becomes binary 
ret, thresh = cv2.threshold(src,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU) 
# You need to choose 4 or 8 for connectivity type 
connectivity = 4 
# Perform the operation 
output = cv2.connectedComponentsWithStats(thresh, connectivity, cv2.CV_32S) 
# Get the results 
# The first cell is the number of labels 
num_labels = output[0] 
# The second cell is the label matrix 
labels = output[1] 
# The third cell is the stat matrix 
stats = output[2] 
# The fourth cell is the centroid matrix 
centroids = output[3] 

Answer 1

stats將是一個2D陣列有關每個blob和保持它的區域中的最後一個元素的每一行保持的信息。所以，簡單地做下面從max-area的blob獲得指標，以min-area BLOB降序排列 -

np.argsort(-stats[:,-1]) # or np.argsort(stats[:,-1])[::-1]