TrueDistanceTransform

Calculates the Eucledian distance to the closest zero pixel for all non-zero pixels of the source image.

Syntax

IppStatus ippiTrueDistanceTransform_8u32f_C1R(const Ipp8u* pSrc, int srcStep, Ipp32f* pDst, int dstStep, IppiSize roiSize, Ipp8u* pBuffer);

IppStatus ippiTrueDistanceTransform_8u16u_C1RSfs(const Ipp8u* pSrc, int srcStep, Ipp16u* pDst, int dstStep, IppiSize roiSize, int scaleFactor, 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 ROI in the destination distance image.
dstStep: Distance in bytes between starts of consecutive lines in the destination image.
roiSize: Size of the image ROI in pixels.
pBuffer: Pointer to the temporary working buffer.
scaleFactor: Scale factor (see Integer Result Scaling).

Description

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

This function calculates the Eucledian distance to the closest zero pixel for all non-zero pixels of the source image [Felz04].

Figure “True Distance Transform, scaleFactor=-5” shows the result of the integer version of the true distance transform of a 7x7 image with zero point in the center and with the scale factor -5.

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 step value is not divisible by 2 for 16u images, and by 4 for 32f images.

True Distance Transform, *scaleFactor*=-5
136	115	101	96	101	115	136
115	91	72	64	72	91	115
101	72	45	36	45	72	101
96	64	36	0	36	64	96
101	72	45	36	45	72	101
115	91	72	64	72	91	115
136	115	101	96	101	115	136

136	115	101	96	101	115	136
115	91	72	64	72	91	115
101	72	45	36	45	72	101
96	64	36	0	36	64	96
101	72	45	36	45	72	101
115	91	72	64	72	91	115
136	115	101	96	101	115	136

136	115	101	96	101	115	136
115	91	72	64	72	91	115
101	72	45	36	45	72	101
96	64	36	0	36	64	96
101	72	45	36	45	72	101
115	91	72	64	72	91	115
136	115	101	96	101	115	136

136	115	101	96	101	115	136
115	91	72	64	72	91	115
101	72	45	36	45	72	101
96	64	36	0	36	64	96
101	72	45	36	45	72	101
115	91	72	64	72	91	115
136	115	101	96	101	115	136