FastMarching

Calculates distance transform to closest zero pixel for all non-zero pixels of source image using fast marching method.

Syntax

IppStatus ippiFastMarching_8u32f_C1R(const Ipp8u* pSrc, int srcStep, Ipp32f* pDst, int dstStep, IppiSize roiSize, Ipp32f radius, Ipp8u* pBuffer);

Parameters

pSrc: Pointer to the source image ROI.
srcStep: Distance in bytes between starts of consecutive lines in the source image.
pDst: Pointer to the destination image ROI.
dstStep: Distance in bytes between starts of consecutive lines in the destination image.
roiSize: Size of the source and destination image ROI.
raduis: Radius of the neighborhod of the marked area.
pBuffer: Pointer to the working buffer.

Description

The function ippiFastMarching is declared in the ippcv.h It operates with ROI (see Regions of Interest in Intel IPP ).

This function computes the distance from the closest zero pixel to each image pixel according to the Fast Marching Method (FMM) [ Telea04 ]. The FMM distance for area Ω with the border ∂Ω is a solution of the equations:

The resulting distance complies with the equation

Here {u₁, v₁} and {u₂, v₂} are coordinates for pair of pixels adjacent to the pixel with {x, y} coordinates.

The area Ω is defined by the non-zero pixel of the image pSrc. If raduis is positive, then the FMM distance with the negative sign is calculated in Euclidean raduis-neighborhood of Ω.

The function requires the working buffer pBuffer whose size should be computed by the function ippiFastMarchingGetBufferSize beforehand.

Figure “Result of the FFM Method shows the result of the fast marching method for the 7x9 image with centered 3x5 non-zero mask and raduis=1.

Result of the FFM Method

  0.0000     0.0000   -1.0000    -1.0000   -1.0000    -1.0000   -1.0000    0.0000    0.0000 
  0.0000     0.7071   -1.e-10   -1.e-10   -1.e-10    -1.e-10   -1.e-10    0.7071   -1.0000
 -1.0000    -1.e-10    0.7071    0.9659    0.9994     0.9659     0.7071   -1.e-10   -1.0000
 -1.0000    -1.e-10    0.9659    1.6730    1.9579     1.6730     0.9659   -1.e-10   -1.0000
 -1.0000    -1.e-10    0.7071    0.9659    0.9994     0.9659     0.7071   -1.e-10   -1.0000
  0.0000     0.7071   -1.e-10   -1.e-10   -1.e-10    -1.e-10   -1.e-10    0.7071   -1.0000
  0.0000    -1.0000   -1.0000   -1.0000   -1.0000     -1.0000   -1.0000   -1.0000    0.0000

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr	Indicates an error condition if one of the specified pointers is NULL.
ippStsSizeErr	Indicates an error condition if roiSize has a field with zero or negative value.
ippStsStepErr	Indicates an error condition if srcStep or dstStep is less than roiSize.width * < pixelSize>.
ippStsNotEvenStepErr	Indicates an error condition if the step value is not divisible by 4 for floating-point images.
ippStsBadArgErr	Indicates an error condition if raduis is negative.