MahalanobisDistance

Qualified name: CDC.color_models.MahalanobisDistance

class MahalanobisDistance(*, reference_pixels, bands_to_use=None, transform=None)

Bases: BaseDistance

A multivariate normal distribution used to describe the color of a set of pixels.

Methods

calculate_distance	Calculate the color distance using mahalanobis for each pixel in the image to the reference.
calculate_statistics	Calculate covariance and average.
from_image_annotation	Create a class instance from a reference image and an annotated mask.
from_pixel_values	Create a class instance from a list of pixel values before bands_to_use and transforms are applied.
get_bands_to_use	Get correct bands to use from supplied alpha channel number and the number of bands in input.
save_pixel_values	Save raw, transformed and selected bands reference pixels to csv files.
save_pixel_values_to_file	Save pixel values to csv file with tab delimiter.
show_statistics	Print the statistics to screen.

Attributes

color_values	Reference pixel values
color_values_raw	Raw pixel values as reference
color_values_transformed	Transformed reference pixel values
covariance	Covariance of the reference pixels.
average	Average of the reference pixels.

Parameters:

• reference_pixels (np.ndarray)

• bands_to_use (tuple[int, ...] | list[int] | None)

• transform (BaseTransform | None)

classmethod from_image_annotation(*, reference, annotated, bands_to_use=None, alpha_channel=-1, transform=None, **kwargs)

Create a class instance from a reference image and an annotated mask.

Parameters:

• reference (Path)

• annotated (Path)

• bands_to_use (tuple[int, ...] | list[int] | None)

• alpha_channel (int | None)

• transform (BaseTransform | None)

• kwargs (Any)

Return type:

BaseDistance

classmethod from_pixel_values(*, pixel_values, bands_to_use=None, alpha_channel=-1, transform=None, **kwargs)

Create a class instance from a list of pixel values before bands_to_use and transforms are applied.

Parameters:

• pixel_values (ndarray)

• bands_to_use (tuple[int, ...] | list[int] | None)

• alpha_channel (int | None)

• transform (BaseTransform | None)

• kwargs (Any)

Return type:

BaseDistance

calculate_distance(image)

Calculate the color distance using mahalanobis for each pixel in the image to the reference.

Parameters:

image (ndarray)

Return type:

ndarray

calculate_statistics()

Calculate covariance and average.

Return type:

None

get_bands_to_use(alpha_channel, number_of_bands)

Get correct bands to use from supplied alpha channel number and the number of bands in input.

Parameters:

• alpha_channel (int | None)

• number_of_bands (int)

Return type:

None

save_pixel_values(output_location, channel_names_in=None, channel_names_out=None)

Save raw, transformed and selected bands reference pixels to csv files.

Parameters:

• output_location (Path)

• channel_names_in (str | None)

• channel_names_out (str | None)

Return type:

None

save_pixel_values_to_file(filename, values, header=None, raw=True)

Save pixel values to csv file with tab delimiter.

Parameters:

• filename (Path)

• values (ndarray)

• header (str | None)

• raw (bool)

Return type:

None

show_statistics()

Print the statistics to screen.

Return type:

None

average: float | None

Average of the reference pixels.

color_values: ndarray

Reference pixel values

color_values_raw: ndarray | None

Raw pixel values as reference

color_values_transformed: ndarray | None

Transformed reference pixel values

covariance: ndarray | None

Covariance of the reference pixels.