Channel Property

Summary

Gets or sets a flag that indicates the channel for which to get the histogram and the bits to use in calculating the histogram.

Syntax

Objective-C

C++/CLI

Java

Python

public HistogramCommandFlags Channel { get; set; }

@property (nonatomic, assign) LTHistogramCommandFlags channel;

public int getChannel(); 
public void setChannel( 
   int intValue 
);

public: 
property HistogramCommandFlags Channel { 
   HistogramCommandFlags get(); 
   void set (    HistogramCommandFlags ); 
}

Channel # get and set (HistogramCommand)

Property Value

Value that indicates the channel for which to get the histogram and the bits to use in calculating the histogram.

Remarks

In order to speed up widely used image processing filters in LEADTOOLS, the grayscale value (master channel) of a colored image is calculated using the following formulas:

#define CalcGrayValue(r, g, b) ((L_UCHAR)(((L_UCHAR) (((2 * (L_UINT) (r)) + (5 * (L_UINT) (g)) + (L_UINT) (b) + 4) / 8)))) 
#define CalcGrayValue16(r, g, b) ((L_UINT16) (((2 * (L_UINT32) (r)) + (5 * (L_UINT32) (g)) + (L_UINT32) (b) + 4) / 8)) 
#define CalcGrayValue32(r, g, b) ((L_UINT32) (((2 * (L_UINT32) (r)) + (5 * (L_UINT32) (g)) + (L_UINT32) (b) + 4) / 8))

Example

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
 
 
public void HistogramCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg")); 
 
   // Prepare the command 
   HistogramCommand command = new HistogramCommand(); 
   long[] histogramValues; 
   //Create the red-channel histogram. 
   command.Channel = HistogramCommandFlags.Red | HistogramCommandFlags.AllBits; 
   command.Run(image); 
   codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24); 
   histogramValues = command.Histogram; 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\LEADTOOLS22\Resources\Images"; 
}

Requirements

Target Platforms

Reference

HistogramCommand Class

HistogramCommand Members

Download our FREE evaluation

Help Version 22.0.2023.3.31