OpenLvVision_OpenCv.lvlib:Dct.vim

Performs a forward or inverse discrete Cosine transform of 1D or 2D array.

The function cv::dct performs a forward or inverse discrete Cosine transform (DCT) of a 1D or 2D floating-point array:

  • Forward Cosine transform of a 1D vector of N elements:
    $ Y = C^{(N)} \cdot X $

    where

    $ C^{(N)}_{jk} = \sqrt{\alpha_j / N}\, \cos\!\left(\frac{\pi(2k+1)j}{2N}\right) $

    and $\alpha_0 = 1$, $\alpha_j = 2$ for $j > 0$.

  • Inverse Cosine transform of a 1D vector of N elements:
    $ X = \left(C^{(N)}\right)^{-1} \cdot Y = \left(C^{(N)}\right)^T \cdot Y $

    (since $C^{(N)}$ is an orthogonal matrix, $C^{(N)} \cdot (C^{(N)})^T = I$)

  • Forward 2D Cosine transform of an $M \times N$ matrix:
    $ Y = C^{(N)} \cdot X \cdot \left(C^{(N)}\right)^T $
  • Inverse 2D Cosine transform of an $M \times N$ matrix:
    $ X = \left(C^{(N)}\right)^T \cdot X \cdot C^{(N)} $

The function chooses the mode of operation by checking the flags and the size of the input array:

  • If (flags & DCT_INVERSE) == 0, a forward 1D or 2D transform is performed; otherwise, an inverse transform.
  • If (flags & DCT_ROWS) != 0, the function performs a 1D transform of each row.
  • If the array is a single row or a single column, the function performs a 1D transform.
  • Otherwise, a 2D transform is performed.

For detailed information, please refer to the OpenCV documentation

OpenLvVision_OpenCv.lvlib:Dct.vim

cerrcodeclst

error in

error in can accept error information wired from VIs previously called. Use this information to decide if any functionality should be bypassed in the event of errors from other VIs.

Right-click the error in control on the front panel and select Explain Error or Explain Warning from the shortcut menu for more information about the error.

    cbool

    		status

    status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.

    Right-click the error in control on the front panel and select Explain Error or Explain Warning from the shortcut menu for more information about the error.

    ci32

    		code

    cstr

    		source

    source describes the origin of the error or warning.

    Right-click the error in control on the front panel and select Explain Error or Explain Warning from the shortcut menu for more information about the error.

cOpenLvVision__OpenCv_lvlib_Anythinglvclass

Src

input floating-point array.

cOpenLvVision__OpenCv_lvlib_Anythinglvclass

Dst

output array of the same size and type as src .

cbool

Inverse

performs an inverse 1D or 2D transform instead of the default forward transform.

cbool

Rows

performs a forward or inverse transform of every individual row of the input matrix. This flag enables you to transform multiple vectors simultaneously and can be used to decrease the overhead (which is sometimes several times larger than the processing itself) to perform 3D and higher-dimensional transforms and so forth.

ierrcodeclst

error out

error in can accept error information wired from VIs previously called. Use this information to decide if any functionality should be bypassed in the event of errors from other VIs.

Right-click the error in control on the front panel and select Explain Error or Explain Warning from the shortcut menu for more information about the error.

    ibool

    		status

    status is TRUE (X) if an error occurred or FALSE (checkmark) to indicate a warning or that no error occurred.

    Right-click the error in control on the front panel and select Explain Error or Explain Warning from the shortcut menu for more information about the error.

    ii32

    		code

    istr

    		source

    source describes the origin of the error or warning.

    Right-click the error in control on the front panel and select Explain Error or Explain Warning from the shortcut menu for more information about the error.

iOpenLvVision__OpenCv_lvlib_Anythinglvclass

Dst out

output array of the same size and type as src .