2-D Autocorrelation

2-D autocorrelation of input matrix

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Libraries:
Computer Vision Toolbox / Statistics

Description

The 2-D Autocorrelation block computes the 2-D autocorrelation of the input vector or matrix.

Examples

Compute Autocorrelation of Input Matrix

Compute autocorrelation of a 5-by-5 input matrix using the 2-D Autocorrelation block.

• Open Script

Ports

Input

Port_1 — Input array

vector | matrix

Input array, specified as a vector or matrix.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | fixed point
Complex Number Support: Yes

Output

Port_1 — Autocorrelation of input

vector | matrix

Autocorrelation of the input array, returned as a vector or matrix. The data type of the output is the same as that of the input.

Data Types: single | double | int8 | int16 | int32 | uint8 | uint16 | uint32 | fixed point
Complex Number Support: Yes

Parameters

For details on fixed-point block parameters, see Specify Fixed-Point Attributes for Blocks (DSP System Toolbox).

Lock data type settings against change by the fixed-point tools — Prevent fixed-point tools from overriding data types

off (default) | on

Select this parameter to prevent the fixed-point tools from overriding the data types you specify in this block. For more information, see Lock the Output Data Type Setting (Fixed-Point Designer).

Block Characteristics

Data Types	double | fixed point | integer | single
Multidimensional Signals	no
Variable-Size Signals	yes

Algorithms

If the input Ais a vector with dimension M-by-1 then the equation for 1-D discrete autocorrelation is:

$$C(n)={\displaystyle \sum _{m=0}^{M-1}A(m)\ast A(m+n)}$$

where $$0\le n\le 2M-1$$.

The output is an autocorrelation vector of size $$(2M-1,1)$$.

If the input A is a matrix with dimension M-by-N then the equation for the 2-D discrete autocorrelation is:

$$C(i,j)={\displaystyle \sum _{m=0}^{(M-1)}{\displaystyle \sum _{n=0}^{(N-1)}A(m,n)\cdot conj(A(m+i,n+j))}}$$

where $$0\le i<2M-1$$ and $$0\le j<2N-1$$.

The dimension of the output autocorrelation matrix is $$(2M-1,2N-1)$$.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced before R2006a