public class LocalHistogramEqualizeCommand : RasterCommand
@interface LTLocalHistogramEqualizeCommand : LTRasterCommand
public class LocalHistogramEqualizeCommand
public ref class LocalHistogramEqualizeCommand : public RasterCommand
This class applies the histogram equalizer locally on the image. The image is divided into local rectangles of dimension (Width, Height). The number of pixels inside each local rectangle are linearized according the histogram calculated for an extended rectangle around each local rectangle. The extended rectangles are of dimension: ((Width+2 * WidthExtension) , ( Height + 2 * HeightExtension)). For an example, see the following drawing:
Use this class to bring out details in an image that has portions that are too dark or too bright. An example of this is a picture taken with a flashlight in a dark room. In such a picture, the subject receives good light while the background is very dark. The application of the local histogram brings out details, but creates a blocky artifact. Use Smooth to reduce the blockiness of the result.
For more information, refer to Changing Brightness and Contrast.
Local Equalize Function - Before
Local Equalize Function - After
View additional platform support for this Local Equalize function.
Run the LocalHistogramEqualizeCommand on an image.
public void LocalHistogramEqualizeCommandExample()
// Load an image
RasterCodecs codecs = new RasterCodecs();
codecs.ThrowExceptionsOnInvalidImages = true;
RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"));
// Prepare the command
LocalHistogramEqualizeCommand command = new LocalHistogramEqualizeCommand();
command.Width = 15;
command.Height = 15;
command.WidthExtension = 100;
command.HeightExtension = 100;
command.Smooth = 0;
command.Type = HistogramEqualizeType.Yuv;
// Local Histogram equalize the image.
codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24);
static class LEAD_VARS
public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images";
Changing Brightness and Contrast
Direct Show .NET | C API | Filters
Media Foundation .NET | C API | Transforms