org.opencv.ximgproc

Class ScanSegment

java.lang.Object

org.opencv.core.Algorithm

org.opencv.ximgproc.ScanSegment

public class ScanSegment
extends Algorithm

Class implementing the F-DBSCAN (Accelerated superpixel image segmentation with a parallelized DBSCAN algorithm) superpixels algorithm by Loke SC, et al. CITE: loke2021accelerated for original paper. The algorithm uses a parallelised DBSCAN cluster search that is resistant to noise, competitive in segmentation quality, and faster than existing superpixel segmentation methods. When tested on the Berkeley Segmentation Dataset, the average processing speed is 175 frames/s with a Boundary Recall of 0.797 and an Achievable Segmentation Accuracy of 0.944. The computational complexity is quadratic O(n2) and more suited to smaller images, but can still process a 2MP colour image faster than the SEEDS algorithm in OpenCV. The output is deterministic when the number of processing threads is fixed, and requires the source image to be in Lab colour format.

Field Summary

Fields inherited from class org.opencv.core.Algorithm

nativeObj

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ScanSegment(long addr)

Method Summary

Modifier and Type	Method and Description
static ScanSegment	__fromPtr__(long addr)
protected void	finalize()
void	getLabelContourMask(Mat image) Returns the mask of the superpixel segmentation stored in the ScanSegment object.
void	getLabelContourMask(Mat image, boolean thick_line) Returns the mask of the superpixel segmentation stored in the ScanSegment object.
void	getLabels(Mat labels_out) Returns the segmentation labeling of the image.
int	getNumberOfSuperpixels() Returns the actual superpixel segmentation from the last image processed using iterate.
void	iterate(Mat img) Calculates the superpixel segmentation on a given image with the initialized parameters in the ScanSegment object.

Methods inherited from class org.opencv.core.Algorithm

clear, empty, getDefaultName, getNativeObjAddr, save

Methods inherited from class java.lang.Object

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

Constructor Detail

ScanSegment

protected ScanSegment(long addr)

Method Detail

__fromPtr__

public static ScanSegment __fromPtr__(long addr)

getNumberOfSuperpixels

public int getNumberOfSuperpixels()

Returns the actual superpixel segmentation from the last image processed using iterate. Returns zero if no image has been processed.

Returns:

automatically generated

iterate

public void iterate(Mat img)

Calculates the superpixel segmentation on a given image with the initialized parameters in the ScanSegment object. This function can be called again for other images without the need of initializing the algorithm with createScanSegment(). This save the computational cost of allocating memory for all the structures of the algorithm.

Parameters:

img - Input image. Supported format: CV_8UC3. Image size must match with the initialized image size with the function createScanSegment(). It MUST be in Lab color space.

getLabels

public void getLabels(Mat labels_out)

Returns the segmentation labeling of the image. Each label represents a superpixel, and each pixel is assigned to one superpixel label.

Parameters:

labels_out - Return: A CV_32UC1 integer array containing the labels of the superpixel segmentation. The labels are in the range [0, getNumberOfSuperpixels()].

getLabelContourMask

public void getLabelContourMask(Mat image,
                                boolean thick_line)

Returns the mask of the superpixel segmentation stored in the ScanSegment object. The function return the boundaries of the superpixel segmentation.

Parameters:

image - Return: CV_8UC1 image mask where -1 indicates that the pixel is a superpixel border, and 0 otherwise.

thick_line - If false, the border is only one pixel wide, otherwise all pixels at the border are masked.

getLabelContourMask

public void getLabelContourMask(Mat image)

Returns the mask of the superpixel segmentation stored in the ScanSegment object. The function return the boundaries of the superpixel segmentation.

Parameters:

image - Return: CV_8UC1 image mask where -1 indicates that the pixel is a superpixel border, and 0 otherwise.

finalize

protected void finalize()
                 throws Throwable

Overrides:

finalize in class Algorithm

Throws:

Throwable