Add threshold minimum algorithm

doc/examples/plot_threshold_minimum.py

@@ -0,0 +1,37 @@
+"""
+==================================
+Minimum Algorithm For Thresholding
+==================================
+
+The minimum algorithm takes a histogram of the image and smooths it
+repeatedly unitl there are only two peaks in the histogram.  Then it
+finds the minimum value between the two peaks.  With the smoothing
+there can be multiple pixel values with the minimum histogram count,
+so you can pick 'min', 'mid', or 'max' of these values.
+
+"""
+import matplotlib.pyplot as plt
+
+from skimage import data
+from skimage.filters.thresholding import threshold_minimum
+
+image = data.camera()
+
+threshold = threshold_minimum(image, bias='min')
+
+binarized = image > threshold
+
+fig, axes = plt.subplots(nrows=2, figsize=(7, 8))
+ax0, ax1 = axes
+plt.gray()
+
+ax0.imshow(image)
+ax0.set_title('Image')
+
+ax1.imshow(binarized)
+ax1.set_title('Thresholded')
+
+for ax in axes:
+    ax.axis('off')
+
+plt.show()