PyramidInitAlloc

Allocates memory and initializes a pyramid structure.

Syntax

IppStatus ippiPyramidInitAlloc(IppiPyramid** ppPyr, int level, IppiSize roiSize, Ipp32f rate);

Parameters

ppPyr: Pointer to the pointer to the pyramid structure.
level: Maximum number of pyramid levels.
roiSize: Size of zero level image ROI in pixels.
rate: Ratio between neighbouring levels (1 < rate ≤ 10).

Description

The function ippiPyramidInitAlloc is declared in the ippcv.h file. This function allocates memory and initializes the structure for the pyramid with level+1 levels.This structure is used by the ippiOpticalFlowPyrLK function for optical flow calculations.

The IppiPyramid structure contains the following fields:

pImage	Pointer to the array of (level+1) layer images.
pStep	Pointer to the array of (level+1) image row step values.
pRoi	Pointer to the array of (level+1) layer image ROIs.
pRate	Pointer to the array of (level+1) ratios of i-th levels to the zero level (rate^-i).
pState	Pointer to the structure to compute the next pyramid layer.
level	Number of levels in the pyramid.

The ippiPyramidInitAlloc function fills pRoi and pRate arrays and the level field. The value of level is equal to the minimum of the input value of the level parameter and the maximum possible number of layers of the pyramid with given rate and zero level size.

Other fields should be specified by the user. The pyramid layer structure pState should be initialized by the functions ippiPyramidLayerDownInitAlloc or ippiPyramidLayerUpInitAlloc. Pyramid layer images can be obtained in many different ways, for example, using the Intel IPP functions ippiPyramidLayerDown and ippiPyramidLayerUp.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error if ppPyr pointer is NULL.
ippStsSizeErr	Indicates an error condition if roiSize has a field with zero or negative value.
ippStsBadArgErr	Indicates an error condition if level is equal to or less than 0, or if rate is out of the range.
ippStsMemAllocErr	Memory allocation error.