Module imagingbook.common

Package imagingbook.common.threshold.adaptive

Class NiblackThresholder

java.lang.Object

imagingbook.common.threshold.adaptive.NiblackThresholder

All Implemented Interfaces:

AdaptiveThresholder, Thresholder

Direct Known Subclasses:

NiblackThresholder.Box, NiblackThresholder.Disk, NiblackThresholder.Gauss

public abstract class NiblackThresholder
extends Object
implements AdaptiveThresholder

This is an implementation of the adaptive thresholder proposed by Niblack in [1]. See Sec. 9.2.2 of [2] for a detailed description. It comes in three different version, depending on the type of local support region:

• NiblackThresholder.Box: uses a rectangular (box-shaped) support region;
• NiblackThresholder.Disk: uses a circular (disk-shaped) support region (see [2], Alg. 9.8);
• NiblackThresholder.Gauss: uses a 2D isotropic Gaussian support region (see [2], Alg. 9.9 and Prog. 9.2).

Note that NiblackThresholder itself is abstract and thus cannot be instantiated.

[1] W. Niblack. "An Introduction to Digital Image Processing". Prentice-Hall (1986).
[2] W. Burger, M.J. Burge, Digital Image Processing – An Algorithmic Introduction, 3rd ed, Springer (2022).

Version:

2022/08/01

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	NiblackThresholder.Box	Implementation of Niblack's adaptive thresholder using a rectangular (box-shaped) support region (concrete implementation of abstract class NiblackThresholder).
static class	NiblackThresholder.Disk	Implementation of Niblack's adaptive thresholder using a circular (disk-shaped) support region (concrete implementation of abstract class NiblackThresholder).
static class	NiblackThresholder.Gauss	Implementation of Niblack's adaptive thresholder using a 2D Gaussian support region (concrete implementation of abstract class NiblackThresholder).
static class	NiblackThresholder.Parameters	Parameters for class NiblackThresholder.
static enum	NiblackThresholder.RegionType

Nested classes/interfaces inherited from interface imagingbook.common.threshold.Thresholder

Thresholder.BackgroundMode

Method Summary

Modifier and Type	Method	Description
static NiblackThresholder	create(NiblackThresholder.RegionType regType, NiblackThresholder.Parameters params)	Static convenience method for creating a NiblackThresholder with a specific support region type.
FloatProcessor	getThreshold(ByteProcessor I)	Calculates a adaptive "threshold surface" for the specified ByteProcessor and returns it as another ByteProcessor.

Methods inherited from class java.lang.Object

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

Methods inherited from interface imagingbook.common.threshold.adaptive.AdaptiveThresholder

threshold, threshold, threshold

Method Details

getThreshold

public FloatProcessor getThreshold(ByteProcessor I)

Description copied from interface: AdaptiveThresholder

Calculates a adaptive "threshold surface" for the specified ByteProcessor and returns it as another ByteProcessor.

Specified by:

getThreshold in interface AdaptiveThresholder

Parameters:

I - the input image

Returns:

the threshold surface

create

public static NiblackThresholder create(NiblackThresholder.RegionType regType,
 NiblackThresholder.Parameters params)

Static convenience method for creating a NiblackThresholder with a specific support region type. Note that NiblackThresholder itself is abstract and cannot be instantiated (see concrete sub-types NiblackThresholder.Box, NiblackThresholder.Disk, NiblackThresholder.Gauss).

Parameters:

regType - support region type

params - other parameters

Returns:

an instance of NiblackThresholder