如何使用opencv函数计算图像（二进制）的孔数

Question

I want to calculate the Euler Number so i need number of connected component and number of the holes in the image. I found the how to find number of connected component. Using this code;

vector<vector<Point>>contours;
vector<Vec4i>hierarchy; 
findContours(mat,contours,hierarchy,CV_RETR_CCOMP,CV_CHAIN_APPROX_SIMPLE ); 
objects_num=contours.size(); 

But i am not sure of the right code for calculation of the connected components. Do you know this code is right?

Secondly ** but I don't know how to calculte the number of holes?The opencv doc says that all of the contours are organized into a two-level hierarchy, Do you know how to gain the number of the holes.

Answer 1

I am trying to extract features from the that image. For example I need euler number, filledArea attributes. For this reason; I am trying to figure out the number of the holes in the melanoma picture and number of connected components. Do you know any function to find these attributes.

PS: I am working on Android platform using opencv for android.

Answer 2

So, I can advice you to begin to study how OpenCV handles the blobs (and the contours that describes the blobs).

If you are interested in blob property like area, centroid, etc, you can use image moments (also have a look at here ).

Try to have a look at those tutorials for handling "finding holes" too, here and here .