boofcv.alg.filter.binary

Class LinearContourLabelChang2004

java.lang.Object

boofcv.alg.filter.binary.LinearContourLabelChang2004

public class LinearContourLabelChang2004
extends java.lang.Object

Finds objects in a binary image by tracing their contours. The output is labeled binary image, set of external and internal contours for each object/blob. Blobs can be defined using a 4 or 8 connect rule. The algorithm works by processing the image in a single pass. When a new object is encountered its contour is traced. Then the inner pixels are labeled. If an internal contour is found it will also be traced. See [1] for all the details. The original algorithm has been modified to use different connectivity rules.

Output: Background pixels (0 in input image) are assigned a value of 0, Each blob is then assigned a unique ID starting from 1 up to the number of blobs.

Internally, the input binary image is copied into another image which will have a 1 pixel border of all zeros around it. This ensures that boundary checks will not need to be done, speeding up the algorithm by about 25%.

[1] Fu Chang and Chun-jen Chen and Chi-jen Lu, "A linear-time component-labeling algorithm using contour tracing technique" Computer Vision and Image Understanding, 2004

Constructor Summary

Constructors

Constructor and Description
LinearContourLabelChang2004(ConnectRule rule) Configures the algorithm.

Method Summary

Modifier and Type	Method and Description
FastQueue<Contour>	getContours()
void	process(GrayU8 binary, GrayS32 labeled) Processes the binary image to find the contour of and label blobs.

Methods inherited from class java.lang.Object

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

Constructor Detail

LinearContourLabelChang2004

public LinearContourLabelChang2004(ConnectRule rule)

Configures the algorithm.

Parameters:

rule - Connectivity rule. 4 or 8

Method Detail

process

public void process(GrayU8 binary,
                    GrayS32 labeled)

Processes the binary image to find the contour of and label blobs.

Parameters:

binary - Input binary image. Not modified.

labeled - Output. Labeled image. Modified.

getContours

public FastQueue<Contour> getContours()