ENTROPY Function (PV-WAVE Extreme Advantage)

Image Processing Toolkit User Guide > Reference A–I > ENTROPY Function (PV-WAVE Extreme Advantage)

Computes the entropy of an array.

Usage

result = ENTROPY(array)

Input Parameters

array—A 2D array.

Returned Value

result—A floating-point scalar value with the array entropy.

Keywords

None.

Discussion

Computes the entropy of array(k, l) as:

where array(k, l) > 0.

Values in array less than or equal to 0 don’t contribute to the entropy calculation because the natural log function is undefined for these values. The entropy of an array of all zeros and/or negative values is undefined.

Example

; Read an image.

image = IMAGE_READ(!IP_Data + 'noise_test.tif')

; Compute the entropy of the image.

ent = ENTROPY(image('pixels'))

PRINT, 'Entropy = ', ent