Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/skimage/measure/entropy.py

@@ -0,0 +1,40 @@
+from numpy import unique
+from scipy.stats import entropy as scipy_entropy
+
+
+def shannon_entropy(image, base=2):
+    """Calculate the Shannon entropy of an image.
+
+    The Shannon entropy is defined as S = -sum(pk * log(pk)),
+    where pk are frequency/probability of pixels of value k.
+
+    Parameters
+    ----------
+    image : (N, M) ndarray
+        Grayscale input image.
+    base : float, optional
+        The logarithmic base to use.
+
+    Returns
+    -------
+    entropy : float
+
+    Notes
+    -----
+    The returned value is measured in bits or shannon (Sh) for base=2, natural
+    unit (nat) for base=np.e and hartley (Hart) for base=10.
+
+    References
+    ----------
+    .. [1] `https://en.wikipedia.org/wiki/Entropy_(information_theory) <https://en.wikipedia.org/wiki/Entropy_(information_theory)>`_
+    .. [2] https://en.wiktionary.org/wiki/Shannon_entropy
+
+    Examples
+    --------
+    >>> from skimage import data
+    >>> shannon_entropy(data.camera())
+    7.047955232423086
+    """
+
+    _, counts = unique(image, return_counts=True)
+    return scipy_entropy(counts, base=base)