What is ~ operator in opencv , C++?

Question

I encountered the following while trying to convert some C++ code that uses OpenCV to Java. I'd like to know what the ~ operator does to the Mat object gradient_grown in the following code and what's the Java equivalent to this?

Mat edge_enhanced_mser      = ~gradient_grown & mser_mask;

http://docs.opencv.org/modules/core/doc/basic_structures.html#matrix-expressions — Mat, Apr 10 '15 at 14:17
if it's an overloaded operator, then why don't look into its source code, or maybe its documentation — Abyx, Apr 10 '15 at 14:18
In Java, you don't overload operators. You write a method, and try to give it a sane name. — kiheru, Apr 10 '15 at 14:24
**Note to future readers:** this is asking about an overloaded operator in a particular library, **not the built-in operator**! — user253751, Apr 10 '15 at 14:35

score 3 · Accepted Answer · edited Jun 20 '20 at 09:12

3

It is the equivalent of the bitwise NOT operator overloaded for the Mat class. In this case, it will invert all bits in the matrix. It is listed in the section Matrix Expressions in the documentation:

Bitwise logical operations: A logicop B, A logicop s, s logicop A, ~A, where logicop is one of : &, |, ^.

In Java, you can use the bitwise_not() method:

bitwise_not

public static void bitwise_not(Mat src, Mat dst)

Inverts every bit of an array.

Note you need a new Mat to store the result:

bitwise_not(gradient_grown, gradient_grown_complement);

edited Jun 20 '20 at 09:12

Community

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answered Apr 10 '15 at 14:11

Anderson Vieira

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Even on an OpenCV `Mat` (whatever that is)? – user253751 Apr 10 '15 at 14:13
Unless it's been overloaded for a class type, as it has here. – Mike Seymour Apr 10 '15 at 14:13
Thanks , I just found out a similar question with the same answer here http://stackoverflow.com/questions/27854370/meaning-of-tilde-operator-in-opencv – Romantic Electron Apr 10 '15 at 14:51

What is ~ operator in opencv , C++?

1 Answers1