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ZeroToNegativeCommand Class

Converts a grayscale unsigned image to a signed image by shifting the image data to the negative side by the amount specified by the user.
public class ZeroToNegativeCommand : RasterCommand 
@interface LTZeroToNegativeCommand : LTRasterCommand 
public class ZeroToNegativeCommand 
    extends RasterCommand 
public ref class ZeroToNegativeCommand : public RasterCommand   
class ZeroToNegativeCommand(RasterCommand): 

This command is similar to ConvertUnsignedToSignedCommand. However, MinimumToZeroCommand updates ShiftAmount with the value by which the intensity values were shifted. The updated ShiftAmount value can be passed to ZeroToNegativeCommand to convert the image back to signed (i.e. after using image processing command that works in unsigned 12-16 bit grayscale image). MinimumToZeroCommand and ZeroToNegativeCommand are most often used in concert with one or more image processing or analysis commands. MinimumToZeroCommand converts signed data to unsigned data, in preparation for image processing or analysis commands that work on unsigned image data. After the image processing or analysis is performed, ZeroToNegativeCommand can be used to converts the unsigned data back to signed data. This command is used usually after the command MinimumToZeroCommand. This command updates the Signed property of the RasterImage. This command also updates the MinValue and MaxValue properties of the RasterImage. This command supports signed data images and supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical toolkits. However, this command does not support 8-bit images. This command does not support 32-bit grayscale images.


This command will apply MultiscaleEnhancementCommand on a signed image, but since MultiscaleEnhancementCommand does not support signed images, we will convert the image to unsigned image, apply the effect, and then convert it back to signed image.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Core; 
public void ZeroToNegativeCommandExample() 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, @"ImageProcessingDemo\Beauty16.jpg")); 
   // Prepare the command 
   // Convert the image to unsigned image by shifting the negative values to become positive. 
   MinimumToZeroCommand MinToZCommand = new MinimumToZeroCommand(); 
   // Apply multiscale enhancement 
   MultiscaleEnhancementCommand MultiScaleCommand = new MultiscaleEnhancementCommand(2000, 4, -1, 0, 0, MultiscaleEnhancementCommandType.Gaussian, MultiscaleEnhancementCommandFlags.EdgeEnhancement); 
   // Convert the image back to signed by shifting the same amount in the negative side. 
   ZeroToNegativeCommand command = new ZeroToNegativeCommand(); 
   command.MinimumInput = -32767; 
   command.MaximumInput = 32766; 
   command.MinimumOutput = 0; 
   command.MaximumOutput = 65535; 
   command.ShiftAmount = MinToZCommand.ShiftAmount; 
static class LEAD_VARS 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 

Target Platforms

Help Version 22.0.2023.3.31
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Leadtools.ImageProcessing.Core Assembly

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© 1991-2023 LEAD Technologies, Inc. All Rights Reserved.