DCT{x}
The real input sequence.
This input can be a 1D or 2D array of doubleprecision, floatingpoint numbers.
error in
Error conditions that occur before this node runs.
The node responds to this input according to standard error behavior.
Many nodes provide an
error in
input and an
error out
output so that the node can respond to and communicate errors that occur while code is running. The value of
error in
specifies whether an error occurred before the node runs. Most nodes respond to values of
error in
in a standard, predictable way.
error in
does not contain an error

error in
contains an error



If no error occurred before the node runs, the node begins execution normally.
If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as
error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the
error in
value as
error out.

Default:
No error
x
The inverse DCT of the real input sequence.
error out
Error information.
The node produces this output according to standard error behavior.
Many nodes provide an
error in
input and an
error out
output so that the node can respond to and communicate errors that occur while code is running. The value of
error in
specifies whether an error occurred before the node runs. Most nodes respond to values of
error in
in a standard, predictable way.
error in
does not contain an error

error in
contains an error



If no error occurred before the node runs, the node begins execution normally.
If no error occurs while the node runs, it returns no error. If an error does occur while the node runs, it returns that error information as
error out.

If an error occurred before the node runs, the node does not execute. Instead, it returns the
error in
value as
error out.

Algorithm Definition for 1D Inverse DCT
If
y
represents a 1D array as the input sequence
DCT{x}, the onedimensional inverse Discrete Cosine Transform of
y
is defined as:
${x}_{n}=\sqrt{\frac{2}{N}}\sum _{k=0}^{N1}{{\alpha}_{k}y}_{k}\mathrm{cos}\frac{(2n+1)k\pi}{2N}$
and
${\alpha}_{k}=\{\begin{array}{c}\frac{1}{\sqrt{2}}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}k=0\\ 1\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}\text{}k=1,\text{}2,\text{}\mathrm{...},\text{}N1\end{array}$
where

N
is the length of
DCT{x}

y
_{
k
}
is the
k
^{th}
element of
DCT{x}

x
_{
n
}
is the
n
^{th}
element of
x
This node applies a fast inverse DCT algorithm instead of calculating the inverse DCT directly. This node implements the fast inverse DCT algorithm using an FFTbased technique.
Algorithm Definition for 2D Inverse DCT
If
y
represents a 2D array as the input sequence
DCT{x}, the twodimensional inverse Discrete Cosine Transform of
y
is defined as:
$x(m,n)=\sqrt{\frac{2}{M}}\sqrt{\frac{2}{N}}\sum _{u=0}^{M1}\sum _{v=0}^{N1}{\alpha}_{u}{\alpha}_{v}y(u,v)\mathrm{cos}\frac{(2m+1)u\pi}{2M}\mathrm{cos}\frac{(2n+1)v\pi}{2N}$
where

M
is the number of rows of
DCT{x}

N
is the number of columns of
DCT{x}
 x(m, n) is the element of
x
with row number
m
and column number
n
 y(u, v) is the element of
DCT{x}
with row number
u
and column number
v
This node performs a twodimensional inverse DCT using the following two steps:

Perform a onedimensional inverse DCT rowbyrow on
DCT{x}. The output is
Y'.

Perform a onedimensional inverse DCT columnbycolumn on
Y'. The output is
x.
Where This Node Can Run:
Desktop OS: Windows
FPGA:
Not supported
Web Server: Not supported in VIs that run in a web application