CODEWITHSUNDEEP
c++opencv
user1807367
user1807367

Reputation:

What does that expression mean in C++

I faced one time in an opencv code this expression:

Mat bimage = image >= sliderPos;

Known that sliderPos is an integer.

What does that mean please.

Thanks in advance

ADDITION: of course the type of image is cv::Mat

Upvotes: 0

Views: 232

Answers (2)

Oswald
Oswald

Reputation: 31647

The expression

Mat bimage = image >= sliderPos;

tests whether image is larger or equal to sliderPos (which usually yields a bool) and assigns the result of the test to the newly created variable bimage of type Mat.

If the >= operator is overloaded for (decltype(image), int), it might not yield a bool. If this is the case, look in the documentation of the type of image for details. In any case, it yields something, from wich a Mat can be constructed.

Upvotes: 1

Luc Touraille
Luc Touraille

Reputation: 82041

It is hard to tell without knowing the type of image, but according to the OpenCV documentation, I think this line converts image into a black and white image, using sliderPos as a threshold to determine which pixels will be black.

From the OpenCV documentation about matrices:

Comparison: A cmpop B, A cmpop alpha, alpha cmpop A, where cmpop is one of : >, >=, ==, !=, <=, <. The result of comparison is an 8-bit single channel mask whose elements are set to 255 (if the particular element or pair of elements satisfy the condition) or 0.

Upvotes: 3

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