Edges — SciPy Filters for QGIS

Gaussian gradient magnitude

class scipy_filters.algs.scipy_gaussian_algorithm.SciPyGaussianGradientMagnitudeAlgorithm

Gradient magnitude using Gaussian derivatives. Calculated with gaussian_gradient_magnitude from scipy.ndimage.

Note

No data cells within the filter radius are filled with 0.

Dimension Calculate for each band separately (2D) or use all bands as a 3D datacube and perform filter in 3D.

Note

bands will be the first axis of the datacube.

Sigma Standard deviation of the gaussian filter. Border mode determines how input is extended around the edges: Reflect (input is extended by reflecting at the edge), Constant (fill around the edges with a constant value), Nearest (extend by replicating the nearest pixel), Mirror (extend by reflecting about the center of last pixel), Wrap (extend by wrapping around to the opposite edge).

Dtype Data type of output. Beware of clipping and potential overflow errors if min/max of output does not fit. Default is Float32.

Gaussian Laplace

class scipy_filters.algs.scipy_gaussian_algorithm.SciPyGaussianLaplaceAlgorithm

Laplace filter using Gaussian second derivatives

Calculated with gaussian_laplace from scipy.ndimage.

Note

No data cells within the filter radius are filled with 0.

Dimension Calculate for each band separately (2D) or use all bands as a 3D datacube and perform filter in 3D.

Note

bands will be the first axis of the datacube.

Sigma Standard deviation of the gaussian filter. Border mode determines how input is extended around the edges: Reflect (input is extended by reflecting at the edge), Constant (fill around the edges with a constant value), Nearest (extend by replicating the nearest pixel), Mirror (extend by reflecting about the center of last pixel), Wrap (extend by wrapping around to the opposite edge).

Dtype Data type of output. Beware of clipping and potential overflow errors if min/max of output does not fit. Default is Float32.

Gradient filter

class scipy_filters.algs.gradient_algorithm.SciPyGradientAlgorithm

Gradient filter. Returns gradient along x-axis, y-axis or the maximum gradient. Calculated with numpy.gradient.

See also Pixel Gradient in Pixel Based Filters.

Note

No data cells within the filter radius are filled with 0.

Axis Calculate along x-axis, y-axis or both (returning the hypotenuse of both vectors.)

Return absolute values Gradient is calculated left to right along x-axis or top to bottom of the raster, eventually returning negative values. If checked, the absolute values are returned.

Laplace filter

class scipy_filters.algs.scipy_edge_algorithms.SciPyLaplaceAlgorithm

Multidimensional Laplace filter based on approximate second derivatives. Calculated with gaussian_laplace from scipy.ndimage.

Note

No data cells within the filter radius are filled with 0.

Dimension Calculate for each band separately (2D) or use all bands as a 3D datacube and perform filter in 3D.

Note

bands will be the first axis of the datacube.

Border mode determines how input is extended around the edges: Reflect (input is extended by reflecting at the edge), Constant (fill around the edges with a constant value), Nearest (extend by replicating the nearest pixel), Mirror (extend by reflecting about the center of last pixel), Wrap (extend by wrapping around to the opposite edge).

Dtype Data type of output. Beware of clipping and potential overflow errors if min/max of output does not fit. Default is Float32.

Prewitt filter

class scipy_filters.algs.scipy_edge_algorithms.SciPyPrewittAlgorithm

Prewitt filter. Calculated with prewitt from scipy.ndimage.

Note

No data cells within the filter radius are filled with 0.

Dimension Calculate for each band separately (2D) or use all bands as a 3D datacube and perform filter in 3D.

Note

bands will be the first axis of the datacube.

Axis: Find horizontal or vertical edges or in case of 3D edges across the bands. Magnitude: all axes combined with hypothenuse of the triangle. Border mode determines how input is extended around the edges: Reflect (input is extended by reflecting at the edge), Constant (fill around the edges with a constant value), Nearest (extend by replicating the nearest pixel), Mirror (extend by reflecting about the center of last pixel), Wrap (extend by wrapping around to the opposite edge).

Dtype Data type of output. Beware of clipping and potential overflow errors if min/max of output does not fit. Default is Float32.

Sobel filter

class scipy_filters.algs.scipy_edge_algorithms.SciPySobelAlgorithm

Sobel filter

Calculated with sobel from scipy.ndimage.

Note

No data cells within the filter radius are filled with 0.

Dimension Calculate for each band separately (2D) or use all bands as a 3D datacube and perform filter in 3D.

Note

bands will be the first axis of the datacube.

Axis: Find horizontal or vertical edges or in case of 3D edges across the bands. Magnitude: all axes combined with hypothenuse of the triangle. Border mode determines how input is extended around the edges: Reflect (input is extended by reflecting at the edge), Constant (fill around the edges with a constant value), Nearest (extend by replicating the nearest pixel), Mirror (extend by reflecting about the center of last pixel), Wrap (extend by wrapping around to the opposite edge).

Dtype Data type of output. Beware of clipping and potential overflow errors if min/max of output does not fit. Default is Float32.