Example Thresholding - Revision history

Peter at 23:32, 17 January 2022

2022-01-17T23:32:15Z

← Older revision		Revision as of 23:32, 17 January 2022
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	</center>		</center>

	Thresholding gray scale images is one of the most basic ways to segment an image. It is quick and effective in many situations. BoofCV provides several algorithms for computing both global and locally adaptive thresholds.		Thresholding gray scale images is one of the most basic ways to segment an image. It is quick and effective in many situations. BoofCV provides several algorithms for computing both global and locally adaptive thresholds.

	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.38/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.40/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	public static void threshold( String imageName ) {		public static void threshold( String imageName ) {
	BufferedImage image = UtilImageIO.~~loadImage~~(imageName);		BufferedImage image = UtilImageIO.loadImageNotNull(imageName);

	// convert into a usable format		// convert into a usable format
	GrayF32 input = ConvertBufferedImage.convertFromSingle(image, null, GrayF32.class);		GrayF32 input = ConvertBufferedImage.convertFromSingle(image, null, GrayF32.class);
	~~GrayU8~~ binary = new GrayU8(input.width, input.height);		var binary = new GrayU8(input.width, input.height);

	// Display multiple images in the same window		// Display multiple images in the same window
	~~ListDisplayPanel~~ gui = new ListDisplayPanel();		var gui = new ListDisplayPanel();

	// Global Methods		// Global Methods

Peter at 19:45, 12 July 2021

2021-07-12T19:45:19Z

← Older revision		Revision as of 19:45, 12 July 2021
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.37/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.38/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	<syntaxhighlight lang="java">		<syntaxhighlight lang="java">
	/**		/**
	* Demonstration of different techniques for automatic thresholding an image to create a binary image. The binary		* Demonstration of different techniques for automatic thresholding an image to create a binary image. The binary
	* image can then be used for shape analysis and other applications. Global methods apply the same threshold		* image can then be used for shape analysis and other applications. Global methods apply the same threshold
	* to the entire image. Local methods compute a local threshold around each pixel and can handle uneven		* to the entire image. Local methods compute a local threshold around each pixel and can handle uneven
	* lighting, but produce noisy results in regions with uniform lighting.		* lighting, but produce noisy results in regions with uniform lighting.
	*		*
			* @author Peter Abeles
	* @see boofcv.examples.imageprocessing.ExampleBinaryOps		* @see boofcv.examples.imageprocessing.ExampleBinaryOps
	*
	* @author Peter Abeles
	*/		*/
	public class ExampleThresholding {		public class ExampleThresholding {
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	// convert into a usable format		// convert into a usable format
	GrayF32 input = ConvertBufferedImage.convertFromSingle(image, null, GrayF32.class);		GrayF32 input = ConvertBufferedImage.convertFromSingle(image, null, GrayF32.class);
	GrayU8 binary = new GrayU8(input.width,input.height);		GrayU8 binary = new GrayU8(input.width, input.height);

	// Display multiple images in the same window		// Display multiple images in the same window
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	// Global Methods		// Global Methods
	GThresholdImageOps.threshold(input, binary, ImageStatistics.mean(input), true);		GThresholdImageOps.threshold(input, binary, ImageStatistics.mean(input), true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Global: Mean");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Global: Mean");
	GThresholdImageOps.threshold(input, binary, GThresholdImageOps.computeOtsu(input, 0, 255), true);		GThresholdImageOps.threshold(input, binary, GThresholdImageOps.computeOtsu(input, 0, 255), true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Global: Otsu");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Global: Otsu");
	GThresholdImageOps.threshold(input, binary, GThresholdImageOps.computeEntropy(input, 0, 255), true);		GThresholdImageOps.threshold(input, binary, GThresholdImageOps.computeEntropy(input, 0, 255), true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Global: Entropy");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Global: Entropy");

	// Local method		// Local method
	GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null,null);		GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: ~~Square~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Local: Mean");
	GThresholdImageOps.~~blockMinMax~~(input, binary, ConfigLength.fixed(21), 1.0, true, 15 );		GThresholdImageOps.localGaussian(input, binary, ConfigLength.fixed(85), 1.0, true, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: ~~Block Min-Max~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Local: Gaussian");
	GThresholdImageOps.~~blockMean~~(input, binary, ConfigLength.fixed(21), 1.0, true );		GThresholdImageOps.localNiblack(input, binary, ConfigLength.fixed(11), 0.30f, true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: ~~Block Mean~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Local: Niblack");
	GThresholdImageOps.~~blockOtsu~~(input, binary, false,ConfigLength.fixed(21),0.5, 1.0, true );		GThresholdImageOps.localSauvola(input, binary, ConfigLength.fixed(11), 0.30f, true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: ~~Block Otsu~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Local: Sauvola");
	GThresholdImageOps.~~localGaussian~~(input, binary, ConfigLength.fixed(85), 1.0, true, ~~null, null~~);		GThresholdImageOps.localWolf(input, binary, ConfigLength.fixed(11), 0.30f, true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"~~Local~~: ~~Gaussian~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Local: Wolf");
	GThresholdImageOps.~~localSauvola~~(input, binary, ConfigLength.fixed(11), 0~~.30f~~, true);		GThresholdImageOps.localNick(input, binary, ConfigLength.fixed(11), -0.2f, true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"~~Local~~: ~~Sauvola~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Local: NICK");
	GThresholdImageOps.~~localNick~~(input, binary, ConfigLength.fixed(11), -0.2f, true);		GThresholdImageOps.blockMinMax(input, binary, ConfigLength.fixed(21), 1.0, true, 15);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"~~Local~~: ~~NICK~~");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Block: Min-Max");
			GThresholdImageOps.blockMean(input, binary, ConfigLength.fixed(21), 1.0, true);
			gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Block: Mean");
			GThresholdImageOps.blockOtsu(input, binary, false, ConfigLength.fixed(21), 0.5, 1.0, true);
			gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null), "Block: Otsu");

	// Sauvola is tuned for text image. Change radius to make it run better in others.		// Sauvola is tuned for text image. Change radius to make it run better in others.

	// Show the image image for reference		// Show the image image for reference
	gui.addImage(ConvertBufferedImage.convertTo(input,null),"Input Image");		gui.addImage(ConvertBufferedImage.convertTo(input, null), "Input Image");

	String fileName = imageName.substring(imageName.lastIndexOf('/')+1);		String fileName = imageName.substring(imageName.lastIndexOf('/') + 1);
	ShowImages.showWindow(gui,fileName);		ShowImages.showWindow(gui, fileName);
	}		}

	public static void main(String[] args) {		public static void main( String[] args ) {
	// example in which global thresholding works best		// example in which global thresholding works best
	threshold(UtilIO.pathExample("particles01.jpg"));		threshold(UtilIO.pathExample("particles01.jpg"));

Peter at 02:39, 22 December 2020

2020-12-22T02:39:40Z

← Older revision		Revision as of 02:39, 22 December 2020
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.33/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.37/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:

Peter at 14:55, 15 March 2019

2019-03-15T14:55:49Z

← Older revision		Revision as of 14:55, 15 March 2019
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.31/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.33/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	// Local method		// Local method
	GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null);		GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null,null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");
	GThresholdImageOps.blockMinMax(input, binary, ConfigLength.fixed(21), 1.0, true, 15 );		GThresholdImageOps.blockMinMax(input, binary, ConfigLength.fixed(21), 1.0, true, 15 );

Peter at 03:00, 17 October 2018

2018-10-17T03:00:37Z

← Older revision		Revision as of 03:00, 17 October 2018
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.29/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.31/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	GThresholdImageOps.localSauvola(input, binary, ConfigLength.fixed(11), 0.30f, true);		GThresholdImageOps.localSauvola(input, binary, ConfigLength.fixed(11), 0.30f, true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Sauvola");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Sauvola");
			GThresholdImageOps.localNick(input, binary, ConfigLength.fixed(11), -0.2f, true);
			gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: NICK");

	// Sauvola is tuned for text image. Change radius to make it run better in others.		// Sauvola is tuned for text image. Change radius to make it run better in others.

Peter at 03:08, 19 March 2018

2018-03-19T03:08:41Z

Peter at 00:16, 21 January 2018

2018-01-21T00:16:48Z

← Older revision		Revision as of 00:16, 21 January 2018
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	* Segmentation		* Segmentation
	* Thresholding		* Thresholding

			Relevant Videos:
			* [https://youtu.be/TGg-xgTyaU8?t=525 New Algorithms in v0.28]

	Relevant Examples/Tutorials:		Relevant Examples/Tutorials:

Peter at 07:01, 20 January 2018

2018-01-20T07:01:21Z

← Older revision		Revision as of 07:01, 20 January 2018
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.23/examples/src/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.28/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	// Local method		// Local method
	GThresholdImageOps.~~localSquare~~(input, binary, 28, 1.0, true, null, null);		GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");
	GThresholdImageOps.localBlockMinMax(input, binary, 10, 1.0, true, 15 );		GThresholdImageOps.localBlockMinMax(input, binary, ConfigLength.fixed(21), 1.0, true, 15 );
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Min-Max");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Min-Max");
	GThresholdImageOps.localGaussian(input, binary, 42, 1.0, true, null, null);		GThresholdImageOps.localBlockMean(input, binary, ConfigLength.fixed(21), 1.0, true );
			gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Mean");
			GThresholdImageOps.localBlockOtsu(input, binary, false,ConfigLength.fixed(21),0.5, 1.0, true );
			gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Otsu");
			GThresholdImageOps.localGaussian(input, binary, ConfigLength.fixed(85), 1.0, true, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Gaussian");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Gaussian");
	GThresholdImageOps.localSauvola(input, binary, 5, 0.30f, true);		GThresholdImageOps.localSauvola(input, binary, ConfigLength.fixed(11), 0.30f, true);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Sauvola");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Sauvola");

Peter at 05:35, 28 March 2016

2016-03-28T05:35:32Z

← Older revision		Revision as of 05:35, 28 March 2016
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.21/examples/src/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.23/examples/src/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	// convert into a usable format		// convert into a usable format
	~~ImageFloat32~~ input = ConvertBufferedImage.convertFromSingle(image, null, ~~ImageFloat32~~.class);		GrayF32 input = ConvertBufferedImage.convertFromSingle(image, null, GrayF32.class);
	~~ImageUInt8~~ binary = new ~~ImageUInt8~~(input.width,input.height);		GrayU8 binary = new GrayU8(input.width,input.height);

	// Display multiple images in the same window		// Display multiple images in the same window

Peter at 05:08, 24 January 2016

2016-01-24T05:08:42Z

← Older revision		Revision as of 05:08, 24 January 2016
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.20/examples/src/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.21/examples/src/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	GThresholdImageOps.localSquare(input, binary, 28, 1.0, true, null, null);		GThresholdImageOps.localSquare(input, binary, 28, 1.0, true, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");
			GThresholdImageOps.localBlockMinMax(input, binary, 10, 1.0, true, 15 );
			gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Min-Max");
	GThresholdImageOps.localGaussian(input, binary, 42, 1.0, true, null, null);		GThresholdImageOps.localGaussian(input, binary, 42, 1.0, true, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Gaussian");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Gaussian");

← Older revision		Revision as of 03:08, 19 March 2018
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	Example Code:		Example Code:
	* [https://github.com/lessthanoptimal/BoofCV/blob/v0.28/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]		* [https://github.com/lessthanoptimal/BoofCV/blob/v0.29/examples/src/main/java/boofcv/examples/segmentation/ExampleThresholding.java ExampleThresholding.java]

	Concepts:		Concepts:
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	GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null);		GThresholdImageOps.localMean(input, binary, ConfigLength.fixed(57), 1.0, true, null, null);
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Square");
	GThresholdImageOps.~~localBlockMinMax~~(input, binary, ConfigLength.fixed(21), 1.0, true, 15 );		GThresholdImageOps.blockMinMax(input, binary, ConfigLength.fixed(21), 1.0, true, 15 );
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Min-Max");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Min-Max");
	GThresholdImageOps.~~localBlockMean~~(input, binary, ConfigLength.fixed(21), 1.0, true );		GThresholdImageOps.blockMean(input, binary, ConfigLength.fixed(21), 1.0, true );
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Mean");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Mean");
	GThresholdImageOps.~~localBlockOtsu~~(input, binary, false,ConfigLength.fixed(21),0.5, 1.0, true );		GThresholdImageOps.blockOtsu(input, binary, false,ConfigLength.fixed(21),0.5, 1.0, true );
	gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Otsu");		gui.addImage(VisualizeBinaryData.renderBinary(binary, false, null),"Local: Block Otsu");
	GThresholdImageOps.localGaussian(input, binary, ConfigLength.fixed(85), 1.0, true, null, null);		GThresholdImageOps.localGaussian(input, binary, ConfigLength.fixed(85), 1.0, true, null, null);