fftConvolve2

2D Convolution using Fast Fourier Transform More...

Functions
AFAPI array	fftConvolve2 (const array &signal, const array &filter, const convMode mode=AF_CONV_DEFAULT)
	C++ Interface for convolution on two dimensional signals. More...
AFAPI af_err	af_fft_convolve2 (af_array *out, const af_array signal, const af_array filter, const af_conv_mode mode)
	C Interface for FFT-based convolution on two dimensional signals. More...

Detailed Description

2D Convolution using Fast Fourier Transform

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.

• No Batch - Single filter applied to single input.
• Filter is Batched - Many filters applied on same input
• Signal is Batched - Single filter applied to a set of inputs.
• Identical Batches - A set of filters applied onto to a set of inputs in one-to-one correspondence.
• Non overlapping Batches - All batched filters are applied to all batched signals. The batch dimension of Signal and Filter should not be the same.

  ---

Function Documentation

AFAPI af_err af_fft_convolve2	(	af_array *	out,
		const af_array	signal,
		const af_array	filter,
		const af_conv_mode	mode
	)

C Interface for FFT-based convolution on two dimensional signals.

Parameters

[out]	out	is convolved array
[in]	signal	is the input signal
[in]	filter	is the signal that shall be used for the convolution operation
[in]	mode	indicates if the convolution should be expanded or not(where output size equals input)

Returns

AF_SUCCESS if the convolution is successful, otherwise an appropriate error code is returned.

AFAPI array af::fftConvolve2	(	const array &	signal,
		const array &	filter,
		const convMode	mode = AF_CONV_DEFAULT
	)

C++ Interface for convolution on two dimensional signals.

Parameters

[in]	signal	is the input signal
[in]	filter	is the signal that shall be used for the convolution operation
[in]	mode	indicates if the convolution should be expanded or not(where output size equals input)

Returns

the convolved array