Question

Is there a way to have a matrix of user-defined type in OpenCV 2.x? Something like :

cv::Mat_<KalmanRGBPixel> backgroundModel;

I know cv::Mat<> is meant for image and mathematic, but I want to hold data in a matrix form. I don’t plan to use inverse, transpose, multiplication, etc., it’s only to store data. I want it to be in matrix form because the pixel_ij of each frame of a video will be linked to backgroundModel_ij.

I know there is a DataType<_Tp> class in core.hpp that needs to be defined for my type but I’m not sure how to do it.

EDIT : KalmanRGBPixel is only a wrapper for cv::KalmanFilter class. As for now, it’s the only member.

... some functions ...
private:
    cv::KalmanFilter kalman;

Thanks for your help.

Answer 1

In the OpenCV documentation it is explained how to add custom types to OpenCV matrices. You need to define the corresponding cv::DataType.

https://docs.opencv.org/master/d0/d3a/classcv_1_1DataType.html

The DataType class is basically used to provide a description of such primitive data types without adding any fields or methods to the corresponding classes (and it is actually impossible to add anything to primitive C/C++ data types). This technique is known in C++ as class traits. It is not DataType itself that is used but its specialized versions […] The main purpose of this class is to convert compilation-time type information to an OpenCV-compatible data type identifier […]

(Yes, finally I answer the question itself in this thread!)