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How to create a Scalar with variable number of channels?

asked 2018-03-28 15:41:57 -0500

Blath gravatar image

I want to create a Scalar which has a variable(integer) number of channels, hopefully all the channels being 0.

int channels = 2;
cv::Scalar(...); //Create Scalar with "channels" number of channels, all with the value of 0
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Did you try all()?

Der Luftmensch gravatar imageDer Luftmensch ( 2018-03-28 15:57:16 -0500 )edit

From what I've tested myself, it returns a 4 channel scalar with all elements set to a given value (which I would set to 0)

Blath gravatar imageBlath ( 2018-03-28 17:28:03 -0500 )edit

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answered 2018-03-29 05:48:35 -0500

rwong gravatar image

cv::Scalar can store a maximum of 4 channels, each containing a double-precision floating point value.

https://github.com/opencv/opencv/blob...

It does not remember how many channels it was initialized with. It will always be 4 channels.

A default-constructed Scalar is already initialized with all-zeroes. This is because it has a user-defined constructor that does not require any arguments, and its body does exactly what you'd expect. Code:

https://github.com/opencv/opencv/blob...

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Asked: 2018-03-28 15:41:57 -0500

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Last updated: Mar 29 '18