Class NPPNativeMethods.NPPi.FilterHarrisCornersBorder

Performs Harris Corner detection on a single channel 8-bit grayscale image and outputs a single channel 32-bit floating point image consisting the corner response at each pixel of the image. The algorithm consists of two phases. The first phase generates the floating point product of XX, YY, and XY gradients at each pixel in the image. The type of gradient used is controlled by the eFilterType and eMaskSize parameters. The second phase averages those products over a window of either 3x3 or 5x5 pixels around the center pixel then generates the Harris corner response at that pixel which is output in the destination image. The Harris response value is determined as H = ((XX///YY - XY///XY) - (nK///((XX + YY)///(XX + YY))))///nScale.

Currently only the NPP_BORDER_REPLICATE border type operation is supported. Borderless output can be accomplished by using a larger source image than the destination and adjusting oSrcSize and oSrcOffset parameters accordingly.

Inheritance
System.Object
NPPNativeMethods.NPPi.FilterHarrisCornersBorder
Inherited Members
System.Object.Equals(System.Object)
System.Object.Equals(System.Object, System.Object)
System.Object.GetHashCode()
System.Object.GetType()
System.Object.MemberwiseClone()
System.Object.ReferenceEquals(System.Object, System.Object)
System.Object.ToString()
Namespace: ManagedCuda.NPP
Assembly: NPP.dll
Syntax
public static class FilterHarrisCornersBorder

Methods

nppiFilterHarrisCornersBorder_8u32f_C1R(CUdeviceptr, Int32, NppiSize, NppiPoint, CUdeviceptr, Int32, NppiSize, DifferentialKernel, MaskSize, MaskSize, Single, Single, NppiBorderType, CUdeviceptr)

1 channel 8-bit unsigned grayscale to 1 channel 32-bit floating point Harris corners response image with border control.

Declaration
public static NppStatus nppiFilterHarrisCornersBorder_8u32f_C1R(CUdeviceptr pSrc, int nSrcStep, NppiSize oSrcSize, NppiPoint oSrcOffset, CUdeviceptr pDst, int nDstStep, NppiSize oSizeROI, DifferentialKernel eFilterType, MaskSize eMaskSize, MaskSize eAvgWindowSize, float nK, float nScale, NppiBorderType eBorderType, CUdeviceptr pDeviceBuffer)
Parameters
Type Name Description
CUdeviceptr pSrc

Source-Image Pointer.
System.Int32 nSrcStep

Source-Image Line Step.
NppiSize oSrcSize

Source image width and height in pixels relative to pSrc.
NppiPoint oSrcOffset

The pixel offset that pSrc points to relative to the origin of the source image.
CUdeviceptr pDst

output edge destination_image_pointer.
System.Int32 nDstStep

output edge destination_image_line_step.
NppiSize oSizeROI

Region-of-Interest (ROI).
DifferentialKernel eFilterType

selects between Sobel or Scharr filter type.
MaskSize eMaskSize

fixed filter mask size to use (3x3 or 5x5 for Sobel).
MaskSize eAvgWindowSize

fixed window mask size to use (3x3 or 5x5).
System.Single nK

Harris Corners constant (commonly used value is 0.04F).
System.Single nScale

output is scaled by this scale factor.
NppiBorderType eBorderType

The border type operation to be applied at source image border boundaries.
CUdeviceptr pDeviceBuffer

pointer to scratch DEVICE memory buffer of size hpBufferSize (see nppiFilterHarrisCornersBorderGetBufferSize() above)
Returns
Type Description
NppStatus

StepError, NotEvenStepError, NullPointerError, AlignmentError, StepError, SizeError

nppiFilterHarrisCornersBorderGetBufferSize(NppiSize, ref Int32)

Calculate scratch buffer size needed for the FilterHarrisCornersBorder function based on destination image SizeROI width and height.

Declaration
public static NppStatus nppiFilterHarrisCornersBorderGetBufferSize(NppiSize oSizeROI, ref int hpBufferSize)
Parameters
Type Name Description
NppiSize oSizeROI

Region-of-Interest (ROI).
System.Int32 hpBufferSize

Required buffer size. Important: hpBufferSize is a host pointer. \ref general_scratch_buffer.
Returns
Type Description
NppStatus

StepError, NotEvenStepError, NullPointerError, AlignmentError, StepError, SizeError