Package boofcv.alg.filter.binary.impl

Class BinaryThinning

java.lang.Object

boofcv.alg.filter.binary.impl.BinaryThinning

public class BinaryThinning
extends Object

Applies binary thinning operators to the input image. Thinning discards most of objects foreground (value one) pixels and leaves behind a "skinny" object which still mostly describes the original object's shape. This implementation is known as the morphological thinning. It works by applying 8 masks to the image sequence. When a mask is applied pixels which need to be set to zero are recorded in a list. After the mask as been applied the pixels are modified, then the next mask is applied. This cycle is repeated until the image no longer changes. Based off the description in [1] using masks from [2]. The masks in those two sources are very similar but there is a one pixel difference which appears to create a smoother image in a couple of test cases.

1. Rafael C. Gonzalez and Richard E. Woods, "Digital Image Processing" 2nd Ed. 2001.
2. http://homepages.inf.ed.ac.uk/rbf/HIPR2/thin.htm, October 31, 2015

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected class	BinaryThinning.Mask	Abstract class for applying the mask.
class	BinaryThinning.Mask0
class	BinaryThinning.Mask1
class	BinaryThinning.Mask2
class	BinaryThinning.Mask3
class	BinaryThinning.Mask4
class	BinaryThinning.Mask5
class	BinaryThinning.Mask6
class	BinaryThinning.Mask7

Field Summary

Fields

Modifier and Type	Field	Description
static byte[]	mask0
static byte[]	mask1
static byte[]	mask2
static byte[]	mask3
static byte[]	mask4
static byte[]	mask5
static byte[]	mask6
static byte[]	mask7

Constructor Summary

Constructors

Constructor	Description
BinaryThinning()

Method Summary

Modifier and Type	Method	Description
void	apply(GrayU8 binary, int maxLoops)	Applies the thinning algorithm.
protected void	findOnePixels(DogArray_I32 ones)	Scans through the image and record the array index of all marked pixels

Methods inherited from class java.lang.Object

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

Field Details

mask0

public static byte[] mask0

mask1

public static byte[] mask1

mask2

public static byte[] mask2

mask3

public static byte[] mask3

mask4

public static byte[] mask4

mask5

public static byte[] mask5

mask6

public static byte[] mask6

mask7

public static byte[] mask7

Constructor Details

BinaryThinning

public BinaryThinning()

Method Details

apply

public void apply(GrayU8 binary,
 int maxLoops)

Applies the thinning algorithm. Runs for the specified number of loops or until no change is detected.

Parameters:

binary - Input binary image which is to be thinned. This is modified

maxLoops - Maximum number of thinning loops. Set to -1 to run until the image is no longer modified.

findOnePixels

protected void findOnePixels(DogArray_I32 ones)

Scans through the image and record the array index of all marked pixels