用于计算 HSI（色相、饱和度、亮度）的类

HSI 算法

根据图像像素的三个颜色分量计算色相、饱和度和亮度值。

使用代码

实现为一个类 CHsi。

//Declaration of class CHsi
// HSI.h file
//
#ifndef __HSI_H__
#define __HSI_H__
#include <math.h>
#define IN
#define OUT
#define PI 3.14159
#define _Max(x,y) ((x)>(y) ? (x) : (y))
#define _Min(x,y) ((x)<(y) ? (x) : (y))

class CHsi
{

public:
  CHsi();
  virtual ~CHsi();
  void HSI(IN unsigned int r,IN unsigned int g,IN unsigned int b,\
          OUT double &Hue,OUT double &Saturation,OUT double &Intensity);
private:
  unsigned int nImax,nImin,nSum,nDifference;

};
#endif// __HSI_H__

//Implementation of class CHsi
#include "Hsi.h"
CHsi::CHsi()
{
  
}

CHsi::~CHsi()
{
  
}

void CHsi::HSI(IN unsigned int r,IN unsigned int g,IN unsigned int b,
          OUT double &Hue,OUT double &Saturation,OUT double &Intensity)
{

  if( (r<0 && g<0 && b<0) || (r>255 || g>255 || b>255) )
  {
    Hue=Saturation=Intensity=0;
    return;
  }

  if(g==b)
  {
    if(b<255)
    {
      b=b+1;
    }
    else
    {
      b=b-1;
    }
  }

  nImax = _Max(r,b);
  nImax = _Max(nImax,g);
  nImin = _Min(r,b);
  nImin = _Min(nImin,g);
  nSum = nImin+nImax;
  nDifference =nImax-nImin;
  
  Intensity = (float)nSum/2;

  if(Intensity<128)
  {
    Saturation=(255*((float)nDifference/nSum));
  }
  else
  {
    Saturation=(float)(255*((float)nDifference/(510-nSum)));
  }

  if(Saturation!=0)
  {
    if(nImax == r)    
    {
      Hue=(60*((float)g-(float)b)/nDifference);
    }
    else if(nImax == g)
    {
      Hue=(60*((float)b-(float)r)/nDifference+120);
    }
    else if(nImax == b)
    {
      Hue=(60*((float)r-(float)g)/nDifference+240);
    }
    
    if(Hue<0)
    {
      Hue=(60*((float)b-(float)r)/nDifference+120);
    }
  }
  else
  {
    Hue=-1;
  }

return;
}

使用 HSI 类。

声明该类的对象，并调用该类的公共函数，提供适当的参数，如下所示。结果值馈送到三个正式参数中，即色相、饱和度和亮度。

#include "Hsi.h"
void main()
{
 int HSINo=5;
 double Hue,Saturation,Intensity;
 CHsi objHsi; //Declaration of the class
 objHsi.HSI (255,251,25,Hue,Saturation,Intensity);//Calling the HSI function
}

关注点

对于颜色处理，用于分离图像中所需的颜色区域非常有用。后续更新敬请期待…