class Threshold – Threshold Object

The threshold object is an attrtuple returned by histogram.get_threshold(). It reports the Otsu-optimal split value for each channel of the underlying Histogram – i.e. the bin value that best separates the channel into a “background” and “foreground” half.

For grayscale histograms, use value (the other three fields are 0). For RGB565 histograms, l_value / a_value / b_value give the Otsu threshold for the LAB L, A, and B channels respectively. The returned values are well-suited to feed directly into Image.binary() or any other method that takes LAB color thresholds.

Fields are accessible by attribute name (threshold.value) or by index (threshold[0]). The object has no public constructor.

class image.threshold

Please call histogram.get_threshold() to create this object.

value

Grayscale Otsu threshold value. Integer 0 – 255. Index [0].

l_value

LAB L channel Otsu threshold value. Integer 0 – 100. Index [1].

a_value

LAB A channel Otsu threshold value. Integer -128 – 127. Index [2].

b_value

LAB B channel Otsu threshold value. Integer -128 – 127. Index [3].