Cara menggunakan 3d gaussian kernel python

Standard deviation for Gaussian kernel. The standard deviations of the Gaussian filter are given for each axis as a sequence, or as a single number, in which case it is equal for all axes.

orderint or sequence of ints, optional

The order of the filter along each axis is given as a sequence of integers, or as a single number. An order of 0 corresponds to convolution with a Gaussian kernel. A positive order corresponds to convolution with that derivative of a Gaussian.

outputarray or dtype, optional

The array in which to place the output, or the dtype of the returned array. By default an array of the same dtype as input will be created.

modestr or sequence, optional

The mode parameter determines how the input array is extended when the filter overlaps a border. By passing a sequence of modes with length equal to the number of dimensions of the input array, different modes can be specified along each axis. Default value is ‘reflect’. The valid values and their behavior is as follows:

‘reflect’ (d c b a | a b c d | d c b a)

The input is extended by reflecting about the edge of the last pixel. This mode is also sometimes referred to as half-sample symmetric.

‘constant’ (k k k k | a b c d | k k k k)

The input is extended by filling all values beyond the edge with the same constant value, defined by the cval parameter.

‘nearest’ (a a a a | a b c d | d d d d)

The input is extended by replicating the last pixel.

‘mirror’ (d c b | a b c d | c b a)

The input is extended by reflecting about the center of the last pixel. This mode is also sometimes referred to as whole-sample symmetric.

‘wrap’ (a b c d | a b c d | a b c d)

The input is extended by wrapping around to the opposite edge.

For consistency with the interpolation functions, the following mode names can also be used:

‘grid-constant’

This is a synonym for ‘constant’.

‘grid-mirror’

This is a synonym for ‘reflect’.

‘grid-wrap’

This is a synonym for ‘wrap’.

cvalscalar, optional

Value to fill past edges of input if mode is ‘constant’. Default is 0.0.

truncatefloat, optional

Truncate the filter at this many standard deviations. Default is 4.0.

radiusNone or int or sequence of ints, optional

Radius of the Gaussian kernel. The radius are given for each axis as a sequence, or as a single number, in which case it is equal for all axes. If specified, the size of the kernel along each axis will be 2*radius + 1, and truncate is ignored. Default is None.

Returns:gaussian_filterndarray

Returned array of same shape as input.

Notes

The multidimensional filter is implemented as a sequence of 1-D convolution filters. The intermediate arrays are stored in the same data type as the output. Therefore, for output types with a limited precision, the results may be imprecise because intermediate results may be stored with insufficient precision.

Cara menggunakan 3d gaussian kernel python

Aly Shmahell

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Aug 25, 2019

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A Tutorial on Generating & Plotting 3D Gaussian Distributions with (Python/Numpy/Tensorflow/Pytorch) & (Matplotlib/Plotly).

Problem Statement:

Whenever plotting Gaussian Distributions is mentioned, it is usually in regard to the Univariate Normal, and that is basically a 2D Gaussian Distribution method that samples from a range array over the X-axis, then applies the Gaussian function to it, and produces the Y-axis coordinates for the plot.

In the case of a 3D Gaussian Distribution however, the sampling happens over both the X-axis and the Y-axis, and the coordinates are projected over the Z-axis. This case is rarely mentioned in tutorials, although it is very useful in many situations.

Solution Outline:

To sample over two axes: X and Y, you need to sample all of the Y-Axis for each sample over the X-axis.

The complete sampling over both axes will produce ranges, one over the X-axis and one over the Y-axis.

When done, you need to generate a domain over the Z-axis, this can be done by calculating the distances of the (X, Y) samples.

The Z domain can then be run through the Gaussian function to produce the Gaussian range over the Z-axis.

A 3D plotter then can be constructed to utilize all three ranges to produce a 3D surface.

Mathematical Breakdown:
  • The X range needs to be a 2D matrix of size:

  • The X intermediate range is a line space (1D range array) from “-domain” to “+domain” with each step the size of “variance”, the number of elements in this 1D array should be:

  • The X range is the result of stacking copies of the X intermediate range, the number of copies should be:

  • The Y range is the transpose of the X range matrix.

  • The Z domain is the distance between X and Y:

  • The Z range is the result of applying the Gaussian function on the distance matrix (the Z domain):

Code Implementations:

Bivariate Normal (Gaussian) Distribution Generator made with Pure Python

  • The X range is constructed without a numpy function.
  • The Y range is the transpose of the X range matrix (ndarray).
  • The final resulting X-range, Y-range, and Z-range are encapsulated with a numpy array for compatibility with the plotters.

Bivariate Normal (Gaussian) Distribution Generator made with Numpy

  • The X intermediate range is constructed with numpy using the “arange” function.
  • The Y intermediate range is constructed with numpy using the “arange” function.
  • The X, Y ranges are constructed with the “meshgrid” function from numpy.

Bivariate Normal (Gaussian) Distribution Generator made with Tensorflow

  • The X intermediate range is constructed with tensorflow using the “range” function.
  • The Y intermediate range is constructed with tensorflow using the “range” function.
  • The X, Y ranges are constructed with the “meshgrid” function from tensorflow.

Bivariate Normal (Gaussian) Distribution Generator made with PyTorch

  • The X intermediate range is constructed with torch using the “arange” function.
  • The Y intermediate range is constructed with torch using the “arange” function.
  • The X, Y ranges are constructed with the “meshgrid” function from torch.

Bivariate Normal Plotter with Matplotlib

Bivariate Normal Plotter with Plotly (Version 4.0.0)

Plotting the Python generated bivariate normal distribution with Matplotlib

plt_plot_bivariate_normal_pdf(*py_bivariate_normal_pdf(6, 4, .25))

Plotting the Numpy generated bivariate normal distribution with Matplotlib

plt_plot_bivariate_normal_pdf(*np_bivariate_normal_pdf(6, 4, .25))

Plotting the Tensorflow generated bivariate normal distribution with Matplotlib

plt_plot_bivariate_normal_pdf(*tf_bivariate_normal_pdf(6, 4, .25))

Plotting the PyTorch generated bivariate normal distribution with Matplotlib

plt_plot_bivariate_normal_pdf(*torch_bivariate_normal_pdf(6, 4, .25))

Plotting the Python generated bivariate normal distribution with Plotly

plotly_plot_bivariate_normal_pdf(*py_bivariate_normal_pdf(6, 4, .25))

Plotting the Numpy generated bivariate normal distribution with Plotly

plotly_plot_bivariate_normal_pdf(*np_bivariate_normal_pdf(6, 4, .25))

Plotting the Tensorflow generated bivariate normal distribution with Plotly

plotly_plot_bivariate_normal_pdf(*tf_bivariate_normal_pdf(6, 4, .25))

Plotting the PyTorch generated bivariate normal distribution with Plotly

plotly_plot_bivariate_normal_pdf(*torch_bivariate_normal_pdf(6, 4, .25))

Note to the reader:

Please feel free to provide feedback, the reason behind these tutorials afterall is to exchange knowledge, and correct course in case of errors.