preprocessing.glcm_padded

Functions

glcm_padded: Computes the GLCM of the NDArray bands with padding.
glcm_padded_cached: Computes the GLCM of the NDArray bands with padding, and caches it.
append_glcm_padded_cached: Computes the GLCM of the NDArray bands with padding, and caches it and also appends it onto the original array.

Usage

We show a few examples of how to use the GLCM functions.

import numpy as np
from glcm_cupy import Features

from frdc.preprocess.glcm_padded import (
    append_glcm_padded_cached, glcm_padded, glcm_padded_cached
)

ar = np.random.rand(50, 25, 4)

# Returns a shape of H x W x C x GLCM Features
ar_glcm = glcm_padded(ar, bin_from=1, bin_to=4, radius=3, )

# Returns a shape of H x W x C x 2
ar_glcm_2_features = glcm_padded(ar, bin_from=1, bin_to=4, radius=3,
                                 features=[Features.CONTRAST,
                                           Features.CORRELATION])

# Returns a shape of H x W x C x GLCM Features
ar_glcm_cached = glcm_padded_cached(ar, bin_from=1, bin_to=4, radius=3)

# Returns a shape of H x W x (C x GLCM Features + C)
ar_glcm_cached_appended = append_glcm_padded_cached(ar, bin_from=1, bin_to=4,
                                                    radius=3)

ar_glcm is the GLCM of the original array, with the last dimension being the GLCM features. The number of features is determined by the features parameter, which defaults to all features.
ar_glcm_2_features selects only 2 features, with the last dimension being the 2 GLCM features specified.
ar_glcm_cached caches the GLCM so that if you call it again, it will return the cached version. It stores its data at the project root dir, under .cache/.
ar_glcm_cached_appended is a wrapper around ar_glcm_cached, it appends the GLCM features onto the original array. It's equivalent to calling ar_glcm_cached and then np.concatenate on the final axes.

Caching

GLCM is an expensive operation, thus we recommend to cache it if the input parameters will be the same. This is especially useful if you're experimenting with the same dataset with constant parameters.

API

glcm_padded(ar, bin_from, bin_to, radius, step_size, features)

Computes the GLCM of the NDArray bands with padding.

ar is the input array
bin_from is the upper bound of the input
bin_to is the upper bound of the GLCM input, i.e. the resolution that GLCM operates on
radius is the radius of the GLCM
step_size is the step size of the GLCM
features is the list of GLCM features to compute

The return shape is

See glcm_cupy for the GLCM Features.

glcm_padded_cached(ar, bin_from, bin_to, radius, step_size, features)

Computes the GLCM of the NDArray bands with padding, and caches it.

See glcm_padded for the parameters and output shape

append_glcm_padded_cached(ar, bin_from, bin_to, radius, step_size, features)

Computes the GLCM of the NDArray bands with padding, and caches it and also appends it onto the original array.

See glcm_padded for the parameters

The return shape is:

The function automatically flattens the last 2 dimensions of the GLCM features, and appends it onto the original array.

Last modified: 26 June 2024