GammaCorrectExtendedCommand Class

Summary

Adjusts the intensity of colors in an image by changing the gamma constant that is used to map the intensity values. Either of two different color spaces can be specified.

Syntax

Objective-C

C++/CLI

Java

Python

public class GammaCorrectExtendedCommand : RasterCommand

@interface LTGammaCorrectExtendedCommand : LTRasterCommand

public class GammaCorrectExtendedCommand 
    extends RasterCommand

public ref class GammaCorrectExtendedCommand : public RasterCommand

class GammaCorrectExtendedCommand(RasterCommand):

Remarks

This command is like the GammaCorrectCommand method, but has been extended to allow the specification of the colorspace to be used.
Intensity values ideally follow a logarithmic progression, because the eye perceives changes in intensity as being equal when the ratio of change is equal. For example, we would see a change from 0.1 to 0.2 as being equal to a change from 0.2 to 0.4.
Gamma is a standard constant that is used to calculate the progression. For most CRTs the gamma constant is in the range of 2.2 to 2.5.
This command 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.
This command does not support 32-bit grayscale images.

If the image has a LUT and you want to work on the image data, set RasterImage.UseLookupTable to false. Then, after calling the method, reset the UselookupTable property to true, as follows:

rasterImage.UseLookupTable = false; 
Method(rasterImage); 
rasterImage.UseLookupTable = true;

Example

Run the GammaCorrectExtendedCommand on an image.

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
 
 
public void GammaCorrectExtendedCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "sample5.cmp")); 
 
   // Prepare the command 
   GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand(); 
 
   // Apply gamma effect on image using the YUV color space and gamma value of 2.50 
   command.Gamma = 250; 
   command.Type = GammaCorrectExtendedCommandType.YuvSpace; 
   command.Run(image); 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24); 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS23\Resources\Images"; 
}

 
import java.io.File; 
import java.io.IOException; 
 
import org.junit.*; 
import org.junit.runner.JUnitCore; 
import org.junit.runner.Result; 
import org.junit.runner.notification.Failure; 
import static org.junit.Assert.*; 
 
import leadtools.*; 
import leadtools.codecs.*; 
import leadtools.imageprocessing.color.*; 
 
 
public void gammaCorrectExtendedCommandExample() { 
 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.setThrowExceptionsOnInvalidImages(true); 
 
   RasterImage image = codecs.load(combine(LEAD_VARS_IMAGES_DIR, "sample5.cmp")); 
   String outputFileName = combine(LEAD_VARS_IMAGES_DIR, "LEAD_gammaCorrectExtendedExample.jpg"); 
 
   // Prepare the command 
   GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand(); 
 
   // Apply gamma effect on image using the YUV color space and gamma value of 2.50 
   command.setGamma(250); 
   command.setType(GammaCorrectExtendedCommandType.YUV_SPACE); 
   command.run(image); 
   System.out.println("Executed changes on loaded image..."); 
 
   codecs.save(image, outputFileName, RasterImageFormat.JPEG, 24); 
   System.out.println("Command run and image saved to " + outputFileName); 
   assertTrue(new File(outputFileName).exists()); 
 
}