不正確的輸出RGB到HSI轉換

Question

我試圖將RGB轉換爲給定圖像的HSI。 但我似乎無法得到正確的輸出。 強度已經是對的。但是，色調和飽和度不停地給相同的結果，-2147483648，只要R + G + B不等於765 我用這個計算器檢查： http://www.had2know.com/technology/hsi-rgb-color-converter-equations.html 和使用這個公式： http://web2.clarkson.edu/class/image_process/RGB_to_HSI.pdf 請指出我做了什麼錯了..謝謝。

#include <iostream> 
#include <cv.h> 
#include <highgui.h> 
#include "rgb.h" 
#include <cmath> 
#include <math.h> 
#include <algorithm> 
using namespace std; 


int main() 
{ 
    char infname[256]; 

    cout << "Enter input image : "; 
    cin >> infname; 
    IplImage *img = cvLoadImage(infname, 0); 
    RgbImage pic(img); 
    int H = img->height; 
    int W = img->width; 

for (int j=0;j<H;j++) 
for (int i=0;i<W;i++) { 
      const double PI = 4.0*atan(1.0); 
     double norm = 0; 
     double R =(double) pic[j][i].r; 
     double G =(double) pic[j][i].g; 
     double B =(double) pic[j][i].b; 
     double omega = 0; 
     double intensity = 0; 
     double hue = 0; 
     double saturation = 0; 
      double r = 0; 
      double g = 0; 
      double b = 0; 

     //Intensity 
     intensity = (double) (R + G + B)/(3.0*255);   

     //norm colours 
     norm = sqrt(pow(r,2) + pow(g,2) + pow(b,2)); 
     r = (double) (R/norm); 
     g = (double) (G/norm); 
     b = (double) (B/norm); 

     //Saturation and Hue 
     if (R + G + B == 765) { 
      saturation = 0; 
      hue = 0; 
     } 

     else { 
      double tmp = min(r, min(g, b)); 
      saturation = 1.0 - ((3.0 * tmp)/ (double)(r + g + b)); 
       if (saturation < 0.5){ 
       saturation = 0; 
        } 
       else if (saturation >= 0.5){ 
       saturation = 1; 
        } 
      } 
     if (saturation != 0) { 
      omega = 0.5 * ((r-g) + (r-b))/sqrt(pow ((r-g),2) + (r-b)*(g-b)); 
      omega = acos(omega); 
      if (B <= G) { 
       hue = omega; 
      } 
      else if (B > G) { 
       hue = 2 * PI - omega; 
      } 
     } 

     //convert it to degrees 
     int resultHue = (int) round((hue * 180.0)/PI); 
     int resultSaturation = (int) (saturation*100.0); 
     int resultIntensity = (int) round(intensity * 255); 

cout<<"Red = "<<R<<", Green = "<<G<<", Blue = "<<B<<endl; 
cout<<"Hue = "<<resultHue<<", Saturation = "<<resultSaturation<<", Intensity = "<<resultIntensity<<endl; 


} 

    return 0; 
    } 

Answer 1

您計算norm使用r，g和b，但他們始終爲0，在這一點上。

Answer 2

#include <iostream> 
#include <cv.h> 
#include <highgui.h> 
#include "rgb.h" 
#include <cmath> 
#include <algorithm> 
#include <fstream> 
using namespace std; 


int main() 
{ 
    char infname[256]; 
    ofstream outputFile; 
    outputFile.open("RGB_HSI.txt"); 

    cout << "Enter input image : "; 
    cin >> infname; 
    IplImage *img = cvLoadImage(infname, 0); 
    RgbImage pic(img); 
    int H = img->height; 
    int W = img->width; 


for (int j=0;j<H;j++) 
for (int i=0;i<W;i++) { 
     double norm = 0; 
     double omega = 0; 
     double R =(double) pic[j][i].r; 
     double G =(double) pic[j][i].g; 
     double B =(double) pic[j][i].b; 
     double intensity = 0; 
     double hue = 0; 
     double saturation = 0; 
      double r = 0; 
      double g = 0; 
      double b = 0; 
      int resultHue = 0; 
      int resultSaturation = 0; 
      int resultIntensity = 0; 

     //Intensity 
     intensity = (double) (R + G + B)/(3.0*255);   

     //norm colours 
     norm = sqrt((R*R) + (G*G) + (B*B)); 
     r = (double) (R/norm); 
     g = (double) (G/norm); 
     b = (double) (B/norm); 

     //Saturation and Hue 
     if (R + G + B == 765) { 
      saturation = 0; 
      hue = 0; 
     } 

     else { 
      double tmp = min(r, min(g, b)); 
      saturation = 1.0 - ((3.0 * tmp)/ (double)(r + g + b)); 
       if (saturation < 0.5){ 
       saturation = 0; 
        } 
       else if (saturation >= 0.5){ 
       saturation = 1; 
        } 
      } 
     if (saturation != 0) { 
      omega = 0.5 * ((r-g) + (r-b))/sqrt(((r-g) * (r-g)) + (r-b)*(g-b)); 
      omega = acos(omega); 
      if (B <= G) { 
       hue = omega; 
      } 
      else if (B > G) { 
       hue = 2 * M_PI - omega; 
      } 
     } 

     //convert it to degrees 
     resultHue = (int) round((hue * 180.0)/M_PI); 
     resultSaturation = (int) (saturation); 
     resultIntensity = (int) round(intensity * 255); 

      if ((R == 0) && (G == 0) && (B== 0)) { 
       resultHue = 0; 
       resultSaturation = 0; 
       resultIntensity = 0; 
      } 

outputFile<<"Red = "<<R<<", Green = "<<G<<", Blue = "<<B<<endl; 
outputFile<<"Hue = "<<resultHue<<", Saturation = "<<resultSaturation<<", Intensity = "<<resultIntensity<<endl; 


} 
outputFile.close(); 
cout << "\nRGB_HSI printed as text file: RGB_HSI.text\n"; 

    return 0; 
    }