dct function
DCT performs a forward or inverse discrete Cosine transform of 1D or 2D array.
For further details, please see: https://docs.opencv.org/master/d2/de8/group__core__array.html#ga85aad4d668c01fbd64825f589e3696d4
Implementation
void dct(InputArray src, OutputArray dst, {int flags = 0}) {
_bindings.Mat_DCT(src.ptr, dst.ptr, flags);
}