medpy.metric.histogram.cosine_2

medpy.metric.histogram.cosine_2(h1, h2)

Cosine simmilarity.

Turns the cosine similarity into a distance measure for normalized, positive histograms.

\[d_{\bar{\cos}}(H, H') = 1 - \frac{2*\arccos d_{\cos}(H, H')}{pi}\]

See cosine for the definition of \(d_{\cos}(H, H')\).

Attributes:

• metric

Attributes for normalized histograms:

• \(d(H, H')\in[0, 1]\)

• \(d(H, H) = 0\)

• \(d(H, H') = d(H', H)\)

Attributes for not-normalized histograms:

• not applicable

Attributes for not-equal histograms:

• not applicable

Parameters:

h1sequence

The first histogram, normalized.

h2sequence

The second histogram, normalized, same bins as h1.

Returns:

cosinefloat

Cosine distance.