Intel® Integrated Performance Primitives Developer Guide and Reference

ID 790148
Date 11/07/2023
Public

A newer version of this document is available. Customers should click here to go to the newest version.

Document Table of Contents

WarpBilinear

MODIFIED API. Performs bilinear warping of the source image using the specified transform coefficients.

Syntax

IppStatus ippiWarpBilinear_<mod>(const Ipp<datatype>* pSrc, IppiSize srcSize, int srcStep, IppiRect srcRoi, Ipp<datatype>* pDst, int dstStep, IppiRect dstRoi, const double coeffs[2][4], int interpolation, Ipp8u* pBuffer);

Supported values for mod:

8u_C1R

16u_C1R

32f_C1R

8u_C3R

16u_C3R

32f_C3R

8u_C4R

16u_C4R

32f_C4R

Include Files

ippi.h

Domain Dependencies

Headers: ippcore.h, ippvm.h, ipps.h

Libraries: ippcore.lib, ippvm.lib, ipps.lib

Parameters

pSrc

Pointer to the source image origin.An array of separate pointers to each plane in case of data in planar format.

srcSize

Size in pixels of the source image.

srcStep

Distance in bytes between starts of consecutive lines in the source image buffer.

srcRoi

Region of interest in the source image (of the IppiRect type).

pDst

Pointer to the destination image origin. An array of separate pointers to each plane in case of data in planar format.

dstStep

Distance in bytes between starts of consecutive lines in the destination image buffer.

dstRoi

Region of interest in the destination image (of the IppiRect type).

coeffs

The bilinear transform coefficients.

interpolation

Specifies the interpolation mode. Use one of the following values:

IPPI_INTER_NN

Nearest neighbor interpolation

IPPI_INTER_LINEAR

Linear interpolation

IPPI_INTER_CUBIC

Cubic interpolation

IPPI_SMOOTH_EDGE

Use edge smoothing in addition to one of the above modes.

pBuffer

Pointer to the external work buffer.

Description

IMPORTANT:
The API of this function has been modified in Intel IPP 9.0 release.

This function operates with ROI (see ROI Processing in Geometric Transforms).

This bilinear warp function transforms the source image pixel coordinates (x,y) according to the following formulas:

x' = c00* x*y + c01* x + c02* y + c03

y' = c10* x*y + c11* x + c12* y + c13

where x' and y' denote the pixel coordinates in the transformed image, and cij are the bilinear transform coefficients passed in the array coeffs.

The bilinear transform preserves equal distances between points on a line.

The transformed part of the source image is resampled using the interpolation mode specified by the interpolation parameter, and written to the destination image ROI.

Figure “Bilinear Transform of an Image” gives an example of applying the bilinear warping function ippiWarpBilinear to a sample image.

Bilinear Transform of an Image

To estimate how the source image ROI will be transformed by the ippiWarpBilinear function, use functions ippiWarpBilinearQuad and ippiGetBilinearBound. To calculate coefficients of the bilinear transform which maps source ROI to a given quadrangle, use ippiGetBilinearTransformfunction.

Before using this function, compute the size of the external work buffer pBuffer using the WarpBilinearGetBufferSize function.

Example shows how to use the ippiWarpBilinear_32f_C1R function.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error condition if one of the specified pointers is NULL.

ippStsSizeErr

Indicates an error condition if any image dimension has zero or negative value.

ippStsStepErr

Indicates an error condition if srcStep or dstStep has a zero or negative value.

ippStsInterpolationErr

Indicates an error condition if interpolation has an illegal value.

ippStsRectErr

Indicates an error condition if width or height of the intersection of the srcRoi and source image is less than or equal to 1.

ippStsCoeffErr

Indicates an error condition if coefficient values are invalid.

ippStsWrongIntersectROIErr

Indicates an error condition if srcRoi has no intersection with the source image.

ippStsWrongIntersectQuad

Indicates a warning that no operation is performed if the transformed source ROI has no intersection with the destination ROI.

See Also