GrayscaleCommand Class

Summary

Converts a 1-bit, 4-bit, 8-bit, 16-bit, 24-bit, or 32-bit image to an 8-bit, 12-bit, or 16-bit grayscale image.

Syntax

Objective-C

C++/CLI

Java

Python

public class GrayscaleCommand : RasterCommand

@interface LTGrayscaleCommand : LTRasterCommand

public class GrayscaleCommand extends RasterCommand

public ref class GrayscaleCommand : public RasterCommand

class GrayscaleCommand(RasterCommand):

Remarks

Support for 12 and 16-bit grayscale images is available only in the Document/Medical Imaging editions.

The resulting image can be an 8-bit, 12-bit, or 16-bit grayscale image. Once the function is complete, the RasterImage.GrayscaleMode property will indicate the type of grayscale image.

When converting to 12-bit or 16-bit grayscale, the RasterImage.GetLookupTable is not used. When converting to 8-bit grayscale, the RasterImage.GetLookupTable is used to get the RGB for each input pixel. The grayscale value corresponding to that RGB triple is used in the destination image.

For more information, refer to Introduction to Image Processing With LEADTOOLS.

For more information, refer to Grayscale Images.

Grayscale 8-bit Function - Before

Grayscale 8-bit Function - After

View additional platform support for this Grayscale 8-bit function.

Example

This example will load a 24-bit image then convert it to a grayscale image with 8, 12 and 16 bits/pixel

Java

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
 
 
public void GrayscaleCommandExample() 
{ 
	RasterCodecs codecs = new RasterCodecs(); 
 
	string srcFileName = Path.Combine(LEAD_VARS.ImagesDir, "Image1.cmp"); 
	string destFileName8 = Path.Combine(LEAD_VARS.ImagesDir, "Image1_grayscale8.jpg"); 
	string destFileName12 = Path.Combine(LEAD_VARS.ImagesDir, "Image1_grayscale12.jpg"); 
	string destFileName16 = Path.Combine(LEAD_VARS.ImagesDir, "Image1_grayscale16.jpg"); 
 
	// Load the source image from disk as 24-bits/pixel 
	RasterImage image = codecs.Load(srcFileName, 24, CodecsLoadByteOrder.Bgr, 1, 1); 
 
	// Check the grayscale mode 
	Console.WriteLine("Grayscale mode of original image = {0}", image.GrayscaleMode); 
 
	// Convert to 8-bit grayscale 
	GrayscaleCommand command = new GrayscaleCommand(); 
	command.BitsPerPixel = 8; 
	command.Run(image); 
 
	// Check the grayscale mode 
	Console.WriteLine("Grayscale mode after grayscale command with 8 bpp = {0}", image.GrayscaleMode); 
 
	// Save it to disk 
 
	codecs.Options.Jpeg.Save.QualityFactor = 2; 
	codecs.Save(image, destFileName8, RasterImageFormat.Jpeg, 8); 
	image.Dispose(); 
 
	// Load the image again this time grayscale to 12-bits/pixel 
	image = codecs.Load(srcFileName, 24, CodecsLoadByteOrder.Bgr, 1, 1); 
	command.BitsPerPixel = 12; 
	command.Run(image); 
	Console.WriteLine("Grayscale mode after grayscale command with 12 bpp = {0}", image.GrayscaleMode); 
	codecs.Options.Jpeg.Save.QualityFactor = 2; 
	codecs.Save(image, destFileName12, RasterImageFormat.Jpeg, 12); 
	image.Dispose(); 
 
	// Load the image again this time grayscale to 16-bits/pixel 
	image = codecs.Load(srcFileName, 24, CodecsLoadByteOrder.Bgr, 1, 1); 
	command.BitsPerPixel = 16; 
	command.Run(image); 
	Console.WriteLine("Grayscale mode after grayscale command with 16 bpp = {0}", image.GrayscaleMode); 
 
	// When saving 16-bit jpegs, you must use lossless quality factor 
	codecs.Options.Jpeg.Save.QualityFactor = 0; 
	codecs.Save(image, destFileName16, RasterImageFormat.Jpeg, 16); 
	image.Dispose(); 
 
	// Clean Up 
	codecs.Dispose(); 
} 
 
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.*; 
 
 
public void grayscaleCommandExample() { 
   final String LEAD_VARS_IMAGES_DIR = "C:\\LEADTOOLS23\\Resources\\Images"; 
   RasterCodecs codecs = new RasterCodecs(); 
   String srcFileName = combine(LEAD_VARS_IMAGES_DIR, "rgsref.cmp"); 
   String destFileName8 = combine(LEAD_VARS_IMAGES_DIR, "rgsref_grayscale8.jpg"); 
   String destFileName12 = combine(LEAD_VARS_IMAGES_DIR, "rgsref_grayscale12.jpg"); 
   String destFileName16 = combine(LEAD_VARS_IMAGES_DIR, "rgsref_grayscale16.jpg"); 
 
   // Load the source image from disk as 24-bits/pixel 
   RasterImage image = codecs.load(srcFileName, 24, CodecsLoadByteOrder.BGR, 1, 1); 
 
   // Check the grayscale mode 
   System.out.printf("Grsyscale mode of original image = %s%n", image.getGrayscaleMode()); 
 
   // Convert to 8-bit grayscale 
   GrayscaleCommand command = new GrayscaleCommand(); 
   command.setBitsPerPixel(8); 
   command.run(image); 
 
   // Check the grayscale mode 
   System.out.printf("Grsyscale mode after grayscale command with 8 bpp = %s%n", image.getGrayscaleMode()); 
 
   // Save it to disk 
 
   codecs.getOptions().getJpeg().getSave().setQualityFactor(2); 
   codecs.save(image, destFileName8, RasterImageFormat.JPEG, 8); 
   image.dispose(); 
 
   // Load the image again this time grayscale to 12-bits/pixel 
   image = codecs.load(srcFileName, 24, CodecsLoadByteOrder.BGR, 1, 1); 
   command.setBitsPerPixel(12); 
   command.run(image); 
   System.out.printf("Grsyscale mode after grayscale command with 12 bpp = %s%n", image.getGrayscaleMode()); 
   codecs.getOptions().getJpeg().getSave().setQualityFactor(2); 
   codecs.save(image, destFileName12, RasterImageFormat.JPEG, 12); 
   image.dispose(); 
 
   // Load the image again this time grayscale to 16-bits/pixel 
   image = codecs.load(srcFileName, 24, CodecsLoadByteOrder.BGR, 1, 1); 
   command.setBitsPerPixel(16); 
   command.run(image); 
   System.out.printf("Grsyscale mode after grayscale command with 16 bpp = %s%n", image.getGrayscaleMode()); 
 
   // When saving 16-bit jpegs, you must use lossless quality factor 
   codecs.getOptions().getJpeg().getSave().setQualityFactor(0); 
   codecs.save(image, destFileName16, RasterImageFormat.JPEG, 16); 
 
   assertTrue("file unsuccessfully saved to " + destFileName16, (new File(destFileName16)).exists()); 
   System.out.printf("File saved successfully to %s%n", destFileName16); 
 
   // Clean Up 
   image.dispose(); 
   codecs.dispose(); 
}

Requirements

Target Platforms

Reference

GrayscaleCommand Members

Leadtools.ImageProcessing Namespace

Leadtools.Drawing.RasterPaintCallbacks

Implementing custom paint

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Help Version 23.0.2024.5.22

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Leadtools.ImageProcessing Namespace

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