Image Filtering

Overview

Functions and classes described in this section are used to perform various linear or non-linear filtering operations on 2D images. More…

// classes

class cv::cuda::Filter;

// global functions

Ptr<Filter>
cv::cuda::createBoxFilter(
    int srcType,
    int dstType,
    Size ksize,
    Point anchor = Point(-1,-1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createBoxMaxFilter(
    int srcType,
    Size ksize,
    Point anchor = Point(-1, -1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createBoxMinFilter(
    int srcType,
    Size ksize,
    Point anchor = Point(-1, -1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createColumnSumFilter(
    int srcType,
    int dstType,
    int ksize,
    int anchor = -1,
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createDerivFilter(
    int srcType,
    int dstType,
    int dx,
    int dy,
    int ksize,
    bool normalize = false,
    double scale = 1,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    );

Ptr<Filter>
cv::cuda::createGaussianFilter(
    int srcType,
    int dstType,
    Size ksize,
    double sigma1,
    double sigma2 = 0,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    );

Ptr<Filter>
cv::cuda::createLaplacianFilter(
    int srcType,
    int dstType,
    int ksize = 1,
    double scale = 1,
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createLinearFilter(
    int srcType,
    int dstType,
    InputArray kernel,
    Point anchor = Point(-1,-1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createMorphologyFilter(
    int op,
    int srcType,
    InputArray kernel,
    Point anchor = Point(-1, -1),
    int iterations = 1
    );

Ptr<Filter>
cv::cuda::createRowSumFilter(
    int srcType,
    int dstType,
    int ksize,
    int anchor = -1,
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    );

Ptr<Filter>
cv::cuda::createScharrFilter(
    int srcType,
    int dstType,
    int dx,
    int dy,
    double scale = 1,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    );

Ptr<Filter>
cv::cuda::createSeparableLinearFilter(
    int srcType,
    int dstType,
    InputArray rowKernel,
    InputArray columnKernel,
    Point anchor = Point(-1,-1),
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    );

Ptr<Filter>
cv::cuda::createSobelFilter(
    int srcType,
    int dstType,
    int dx,
    int dy,
    int ksize = 3,
    double scale = 1,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    );

Detailed Documentation

Functions and classes described in this section are used to perform various linear or non-linear filtering operations on 2D images.

• An example containing all basic morphology operators like erode and dilate can be found at opencv_source_code/samples/gpu/morphology.cpp

Global Functions

Ptr<Filter>
cv::cuda::createBoxFilter(
    int srcType,
    int dstType,
    Size ksize,
    Point anchor = Point(-1,-1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates a normalized 2D box filter.

Parameters:

srcType	Input image type. Only CV_8UC1, CV_8UC4 and CV_32FC1 are supported for now.
dstType	Output image type. Only the same type as src is supported for now.
ksize	Kernel size.
anchor	Anchor point. The default value Point(-1, -1) means that the anchor is at the kernel center.
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

See also:

boxFilter

Ptr<Filter>
cv::cuda::createBoxMaxFilter(
    int srcType,
    Size ksize,
    Point anchor = Point(-1, -1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates the maximum filter.

Parameters:

srcType	Input/output image type. Only CV_8UC1 and CV_8UC4 are supported.
ksize	Kernel size.
anchor	Anchor point. The default value (-1) means that the anchor is at the kernel center.
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

Ptr<Filter>
cv::cuda::createBoxMinFilter(
    int srcType,
    Size ksize,
    Point anchor = Point(-1, -1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates the minimum filter.

Parameters:

srcType	Input/output image type. Only CV_8UC1 and CV_8UC4 are supported.
ksize	Kernel size.
anchor	Anchor point. The default value (-1) means that the anchor is at the kernel center.
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

Ptr<Filter>
cv::cuda::createColumnSumFilter(
    int srcType,
    int dstType,
    int ksize,
    int anchor = -1,
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates a vertical 1D box filter.

Parameters:

srcType	Input image type. Only CV_8UC1 type is supported for now.
dstType	Output image type. Only CV_32FC1 type is supported for now.
ksize	Kernel size.
anchor	Anchor point. The default value (-1) means that the anchor is at the kernel center.
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

Ptr<Filter>
cv::cuda::createDerivFilter(
    int srcType,
    int dstType,
    int dx,
    int dy,
    int ksize,
    bool normalize = false,
    double scale = 1,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    )

Creates a generalized Deriv operator.

Parameters:

srcType	Source image type.
dstType	Destination array type.
dx	Derivative order in respect of x.
dy	Derivative order in respect of y.
ksize	Aperture size. See getDerivKernels for details.
normalize	Flag indicating whether to normalize (scale down) the filter coefficients or not. See getDerivKernels for details.
scale	Optional scale factor for the computed derivative values. By default, no scaling is applied. For details, see getDerivKernels .
rowBorderMode	Pixel extrapolation method in the vertical direction. For details, see borderInterpolate.
columnBorderMode	Pixel extrapolation method in the horizontal direction.

Ptr<Filter>
cv::cuda::createGaussianFilter(
    int srcType,
    int dstType,
    Size ksize,
    double sigma1,
    double sigma2 = 0,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    )

Creates a Gaussian filter.

Parameters:

srcType	Source image type.
dstType	Destination array type.
ksize	Aperture size. See getGaussianKernel for details.
sigma1	Gaussian sigma in the horizontal direction. See getGaussianKernel for details.
sigma2	Gaussian sigma in the vertical direction. If 0, then \(\texttt{sigma2}\leftarrow\texttt{sigma1}\).
rowBorderMode	Pixel extrapolation method in the vertical direction. For details, see borderInterpolate.
columnBorderMode	Pixel extrapolation method in the horizontal direction.

See also:

GaussianBlur

Ptr<Filter>
cv::cuda::createLaplacianFilter(
    int srcType,
    int dstType,
    int ksize = 1,
    double scale = 1,
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates a Laplacian operator.

Parameters:

srcType	Input image type. Supports CV_8U , CV_16U and CV_32F one and four channel image.
dstType	Output image type. Only the same type as src is supported for now.
ksize	Aperture size used to compute the second-derivative filters (see getDerivKernels). It must be positive and odd. Only ksize = 1 and ksize = 3 are supported.
scale	Optional scale factor for the computed Laplacian values. By default, no scaling is applied (see getDerivKernels ).
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

See also:

Laplacian

Ptr<Filter>
cv::cuda::createLinearFilter(
    int srcType,
    int dstType,
    InputArray kernel,
    Point anchor = Point(-1,-1),
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates a non-separable linear 2D filter.

Parameters:

srcType	Input image type. Supports CV_8U , CV_16U and CV_32F one and four channel image.
dstType	Output image type. Only the same type as src is supported for now.
kernel	2D array of filter coefficients.
anchor	Anchor point. The default value Point(-1, -1) means that the anchor is at the kernel center.
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

See also:

filter2D

Ptr<Filter>
cv::cuda::createMorphologyFilter(
    int op,
    int srcType,
    InputArray kernel,
    Point anchor = Point(-1, -1),
    int iterations = 1
    )

Creates a 2D morphological filter.

Parameters:

op	Type of morphological operation. The following types are possible: MORPH_ERODE erode MORPH_DILATE dilate MORPH_OPEN opening MORPH_CLOSE closing MORPH_GRADIENT morphological gradient MORPH_TOPHAT “top hat” MORPH_BLACKHAT “black hat”
srcType	Input/output image type. Only CV_8UC1, CV_8UC4, CV_32FC1 and CV_32FC4 are supported.
kernel	2D 8-bit structuring element for the morphological operation.
anchor	Anchor position within the structuring element. Negative values mean that the anchor is at the center.
iterations	Number of times erosion and dilation to be applied.

See also:

morphologyEx

Ptr<Filter>
cv::cuda::createRowSumFilter(
    int srcType,
    int dstType,
    int ksize,
    int anchor = -1,
    int borderMode = BORDER_DEFAULT,
    Scalar borderVal = Scalar::all(0)
    )

Creates a horizontal 1D box filter.

Parameters:

srcType	Input image type. Only CV_8UC1 type is supported for now.
dstType	Output image type. Only CV_32FC1 type is supported for now.
ksize	Kernel size.
anchor	Anchor point. The default value (-1) means that the anchor is at the kernel center.
borderMode	Pixel extrapolation method. For details, see borderInterpolate .
borderVal	Default border value.

Ptr<Filter>
cv::cuda::createScharrFilter(
    int srcType,
    int dstType,
    int dx,
    int dy,
    double scale = 1,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    )

Creates a vertical or horizontal Scharr operator.

Parameters:

srcType	Source image type.
dstType	Destination array type.
dx	Order of the derivative x.
dy	Order of the derivative y.
scale	Optional scale factor for the computed derivative values. By default, no scaling is applied. See getDerivKernels for details.
rowBorderMode	Pixel extrapolation method in the vertical direction. For details, see borderInterpolate.
columnBorderMode	Pixel extrapolation method in the horizontal direction.

See also:

Scharr

Ptr<Filter>
cv::cuda::createSeparableLinearFilter(
    int srcType,
    int dstType,
    InputArray rowKernel,
    InputArray columnKernel,
    Point anchor = Point(-1,-1),
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    )

Creates a separable linear filter.

Parameters:

srcType	Source array type.
dstType	Destination array type.
rowKernel	Horizontal filter coefficients. Support kernels with size <= 32 .
columnKernel	Vertical filter coefficients. Support kernels with size <= 32 .
anchor	Anchor position within the kernel. Negative values mean that anchor is positioned at the aperture center.
rowBorderMode	Pixel extrapolation method in the vertical direction For details, see borderInterpolate.
columnBorderMode	Pixel extrapolation method in the horizontal direction.

See also:

sepFilter2D

Ptr<Filter>
cv::cuda::createSobelFilter(
    int srcType,
    int dstType,
    int dx,
    int dy,
    int ksize = 3,
    double scale = 1,
    int rowBorderMode = BORDER_DEFAULT,
    int columnBorderMode = -1
    )

Creates a Sobel operator.

Parameters:

srcType	Source image type.
dstType	Destination array type.
dx	Derivative order in respect of x.
dy	Derivative order in respect of y.
ksize	Size of the extended Sobel kernel. Possible values are 1, 3, 5 or 7.
scale	Optional scale factor for the computed derivative values. By default, no scaling is applied. For details, see getDerivKernels .
rowBorderMode	Pixel extrapolation method in the vertical direction. For details, see borderInterpolate.
columnBorderMode	Pixel extrapolation method in the horizontal direction.

See also:

Sobel