//! computes PSNR image/video quality metric

CV_EXPORTS_W double PSNR(InputArray src1, InputArray src2);

CV_EXPORTS_W void createHanningWindow(OutputArray dst, Size winSize, int type);

//! type of the threshold operation

Calculates the cross-power spectrum of two supplied source arrays. The arrays are padded if needed with :ocv:func:`getOptimalDFTSize`.

    :param src1: Source floating point array (CV_32FC1 or CV_64FC1)

    :param src2: Source floating point array (CV_32FC1 or CV_64FC1)

    :param window: Floating point array with windowing coefficients to reduce edge effects (optional).

Return value: detected phase shift (sub-pixel) between the two arrays.

* Next it computes the forward DFTs of each source array:

        \mathbf{G}_a = \mathcal{F}\{src_1\}, \; \mathbf{G}_b = \mathcal{F}\{src_2\}

  where

* It then computes the cross-power spectrum of each frequency domain array:

          R = \frac{ \mathbf{G}_a \mathbf{G}_b^*}{|\mathbf{G}_a \mathbf{G}_b^*|}

* Next the cross-correlation is converted back into the time domain via the inverse DFT:

          r = \mathcal{F}^{-1}\{R\}

* Finally, it computes the peak location and computes a 5x5 weighted centroid around the peak to achieve sub-pixel accuracy.

         (\Delta x, \Delta y) = \texttt{weightedCentroid} \{\arg \max_{(x, y)}\{r\}\}

.. seealso::

    :ocv:func:`dft`,

    :ocv:func:`getOptimalDFTSize`,

    merge(planes, out);

}

{

    Mat src = _src.getMat();

        }

    }

    sumIntensity += DBL_EPSILON; // prevent div0 problems...

    centroid.x /= sumIntensity;

}

{

    Mat src1 = _src1.getMat();

    Mat src2 = _src2.getMat();

    // get the phase shift with sub-pixel accuracy, 5x5 window seems about right here...

    Point2d t;

    // adjust shift relative to image center...

    Point2d center((double)padded1.cols / 2.0, (double)padded1.rows / 2.0);