
Convolution Integral for two dimensional data. More...
Functions  
AFAPI array  convolve2 (const array &signal, const array &filter, const convMode mode=AF_CONV_DEFAULT, const convDomain domain=AF_CONV_AUTO) 
C++ Interface for convolution on two dimensional signals. More...  
AFAPI af_err  af_convolve2 (af_array *out, const af_array signal, const af_array filter, const af_conv_mode mode, af_conv_domain domain) 
C Interface for convolution on two dimensional signals. More...  
Convolution Integral for two dimensional data.
A convolution is a common operation between a source array, a, and a filter (or kernel) array b. The answer to the convolution is the same as computing the coefficients in polynomial multiplication, if a and b are the coefficients.
Another way to think about it is that the filter kernel is centered on each pixel in a, and the output for that pixel or data point is the sum of the products.
Depending on the dimensions of the input signal and the filter signal, any one of the following batch mode convolutions take place.
For example, if the signal is two dimensional with m & n as sizes along the 0th & 1st dimensions respectively, then the possible batch operations are as follows.
Input Signal Dimensions  Filter Dimensions  Output Dimensions  Batch Mode  Explanation 

[m n 1 1]  [m n 1 1]  [m n 1 1]  No Batch  Output will be a single convolve array 
[m n 1 1]  [m n p 1]  [m n p 1]  Filter is Batched  p filters applied to same input 
[m n p 1]  [m n 1 1]  [m n p 1]  Signal is Batched  1 filter applied to p inputs 
[m n p 1]  [m n p 1]  [m n p 1]  Identical Batches  p filters applied to p inputs in onetoone correspondence 
[m n p 1]  [m n 1 q]  [m n p q]  Nonoverlapping batches  q filters applied to p inputs in to produce p x q results 
[m n 1 p]  [m n q 1]  [m n q p]  Nonoverlapping batches  q filters applied to p inputs in to produce q x p results 
AFAPI af_err af_convolve2  (  af_array *  out, 
const af_array  signal,  
const af_array  filter,  
const af_conv_mode  mode,  
af_conv_domain  domain  
) 
C Interface for convolution on two dimensional signals.
[out]  out  is convolved array 
[in]  signal  is the input signal 
[in]  filter  is the signal that shall be flipped for the convolution operation 
[in]  mode  indicates if the convolution should be expanded or not(where output size equals input) 
[in]  domain  specifies if the convolution should be performed in frequency os spatial domain 
domain
, AF_CONV_AUTO, heuristically switches between frequency and spatial domain. AFAPI array af::convolve2  (  const array &  signal, 
const array &  filter,  
const convMode  mode = AF_CONV_DEFAULT , 

const convDomain  domain = AF_CONV_AUTO 

) 
C++ Interface for convolution on two dimensional signals.
[in]  signal  is the input signal 
[in]  filter  is the signal that shall be flipped for the convolution operation 
[in]  mode  indicates if the convolution should be expanded or not(where output size equals input) 
[in]  domain  specifies if the convolution should be performed in frequency os spatial domain 
domain
, AF_CONV_AUTO, heuristically switches between frequency and spatial domain.