Module org.scijava.ops.image

Package org.scijava.ops.image.threshold.isoData

Class ComputeIsoDataThreshold<T extends RealType<T>>

java.lang.Object

org.scijava.ops.image.threshold.AbstractComputeThresholdHistogram<T>

org.scijava.ops.image.threshold.isoData.ComputeIsoDataThreshold<T>

All Implemented Interfaces:

BiConsumer<Histogram1d<T>,T>, Computers.Arity1<Histogram1d<T>,T>

public class ComputeIsoDataThreshold<T extends RealType<T>>
extends AbstractComputeThresholdHistogram<T>

Implements an IsoData (intermeans) threshold method by Ridler & Calvard.

Author:

Barry DeZonia, Gabriel Landini

Implementation Note:

op names='threshold.isoData', priority='100.'

Constructor Summary

Constructors

Constructor	Description
ComputeIsoDataThreshold()

Method Summary

Modifier and Type	Method	Description
static long	computeBin(long[] histogram)	Also called intermeans Iterative procedure based on the isodata algorithm [T.W.
long	computeBin(Histogram1d<T> hist)	TODO

Methods inherited from class org.scijava.ops.image.threshold.AbstractComputeThresholdHistogram

compute

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.function.BiConsumer

andThen

Methods inherited from interface org.scijava.function.Computers.Arity1

accept

Constructor Detail

ComputeIsoDataThreshold

public ComputeIsoDataThreshold()

Method Detail

computeBin

public long computeBin(Histogram1d<T> hist)

TODO

Specified by:

computeBin in class AbstractComputeThresholdHistogram<T extends RealType<T>>

Parameters:

hist - the Histogram1d

Returns:

the IsoData threshold value

computeBin

public static long computeBin(long[] histogram)

Also called intermeans
Iterative procedure based on the isodata algorithm [T.W. Ridler,
S. Calvard, Picture thresholding using an iterative selection method,
IEEE Trans. System, Man and Cybernetics, SMC-8 (1978) 630-632.]
The procedure divides the image into objects and background by taking
an
initial threshold, then the averages of the pixels at or below the
threshold and pixels above are computed. The averages of those two
values
are computed, the threshold is incremented and the process is
repeated
until the threshold is larger than the composite average. That is,
threshold = (average background + average objects)/2
The code in ImageJ that implements this function is the
getAutoThreshold() method in the ImageProcessor class.

From: Tim Morris (dtm@ap.co.umist.ac.uk)
Subject: Re: Thresholding method?
posted to sci.image.processing on 1996/06/24
The algorithm implemented in NIH Image sets the threshold as that
grey
value, G, for which the average of the averages of the grey values
below and above G is equal to G. It does this by initialising G to
the
lowest sensible value and iterating:

L = the average grey value of pixels with intensities < G
H = the average grey value of pixels with intensities > G
is G = (L + H)/2?
yes => exit
no => increment G and repeat

There is a discrepancy with IJ because of slightly different methods