Negativer Wert bei der Berechnung der Varianz eines Bildes -java-

Question

Hier versuche ich die Varianz eines Bildes zu berechnen, beginnend mit der Varince jeder Farbe in diesem Bild (ich habe die Varianz der roten Farbe berechnet, aber das Ergebnis ist - 1)

Ich benutze die folgende Formel "var (x) = E (x²) -E (x) ²".

private void openActionPerformed(java.awt.event.ActionEvent evt) {          
    LoadImage loadImage = new LoadImage(null); 
    int w, h; 
    BufferedImage image; 
    float somR = 0; 
    int somG = 0; 
    int somB = 0; 
    int valR[][]; 
    int[][] valG; 
    int valB[][]; 
    double meanR = 0; 
    double meanG = 0; 
    double meanB = 0; 
    int nbpixl = 0; 
    try { 
     if (loadImage.loadImage(jScrollPane1)) { 
      int pixel = 0; 

      image = loadImage.getImage(); 
      w = image.getWidth(); 
      h = image.getHeight(); 
      System.out.println("width, height: " + w + ", " + h); 
      nbpixl = w * h; 

      valR = new int[h][w]; 
      valB = new int[h][w]; 
      valG = new int[h][w]; 
      for (int i = 0; i < h; i++) { 
       for (int j = 0; j < w; j++) { 

        pixel = image.getRGB(j, i); 
        //rgb argb 

        //int alpha = (pixel >> 24) & 0xff; 
        int red = (pixel >> 16) & 0xff; 
        int green = (pixel >> 8) & 0xff; 
        int blue = (pixel) & 0xff; 

        valR[i][j] = red; 
        somR += red; 

        valG[i][j] = green; 
        somG += green; 

        valB[i][j] = blue; 
        somB += blue; 

        System.out.println(""); 

       } 

      } 

      System.out.println("red " + somR); 
      System.out.println("green " + somG); 
      System.out.println("blue " + somB); 
      meanR = somR/nbpixl; 
      meanG = somG/nbpixl; 
      meanB = somB/nbpixl; 
      System.out.println("meanR" + meanR); 
      System.out.println("meanV" + meanG); 
      System.out.println("meanB" + meanB); 



      float summSquareR = somR * somR; 
      float meanSquareR = summSquareR/nbpixl; 

      System.out.println("summSquareR" + summSquareR); 
      System.out.println("meanSquareR" + meanSquareR); 
      //float varRrr=(float) (meanSquareR-meanR*meanR); 

      //var (x) = E (x²) -E (x) ² 

      byte varR = (byte) (255f * (meanSquareR - meanR * meanR)); 
      // byte varG=(byte)(225f*((somG*somG)/nbpixl)-((somG/nbpixl)*(somG/nbpixl))); 
      System.out.println(somB + "\t" + somR + "\t" + somG); 
      System.out.println("varR\t" + varR); 

     } 
    } catch (IOException ex) { 
     Logger.getLogger(var_img.class.getName()).log(Level.SEVERE, null, ex); 
    } 
} 

Und für das Ergebnis Breite, Höhe: 259, 194

rot 5.137.653,0

grün 4165933

blau 4142841

meanR102.24999237060547

meanV82. 0

meanB82.0

summSquareR2.63954786E13

meanSquareR5.2532496E8

4142841 5137653,0 4165933

Varr -1

Answer 1

Sie haben die Formel zu verstehen:

E[X^2]=(x1*x1+x2*x2+...+xn*xn)/n 

Ein richtiger Weg, um diese Formel zu verwenden, ist die folgende - d und d2 das gleiches kommen soll:

int[] x={1, 2, 5, 7}; 
int s=0; 
for(int i=0; i<x.length; i++) s+=x[i]; 
double m=s/4.; 
double d=0; 
for(int i=0; i<x.length; i++) d+=(x[i]-m)*(x[i]-m); 
d/=4.; 
int s2=0; 
for(int i=0; i<x.length; i++) s2+=x[i]*x[i]; 
double m2=s2/4.; 
double d2=m2-m*m; 

System.out.println(m+" "+d+" "+d2+" "+m2); 

Answer 2

Code eingeben hier

private void openActionPerformed(java.awt.event.ActionEvent evt) { 
    LoadImage loadImage = new LoadImage(null); 
    int w = 0, h = 0; 
    BufferedImage image; 
    float somR = 0; 
    int somG = 0; 
    int somB = 0; 
    int valR[][]; 
    int[][] valG; 
    int valB[][]; 
    float meanR = 0; 
    float meanG = 0; 
    float meanB = 0; 
    int nbpixl = 0; 

    float square_Red = 0, square_Blue = 0, square_Green = 0; 
    //The sum of pixels for each color 
    int sum_Square_Red = 0, sum_Square_Blue = 0, sum_Square_Green = 0; 
    // The square sum of the pixels for each color 
    float varR = 0, varG = 0, varB = 0;//The variance of each color 
    try { 
     if (loadImage.loadImage(jScrollPane1)) { 
      int pixel = 0; 

      image = loadImage.getImage(); 
      w = image.getWidth(); 
      h = image.getHeight(); 
      System.out.println("width, height: " + w + ", " + h); 
      nbpixl = w * h; 

      valR = new int[h][w]; 
      valB = new int[h][w]; 
      valG = new int[h][w]; 
      for (int i = 0; i < h; i++) { 
       for (int j = 0; j < w; j++) { 
        pixel = image.getRGB(j, i); 
        int red = (pixel >> 16) & 0xff; 
        int green = (pixel >> 8) & 0xff; 
        int blue = (pixel) & 0xff; 

        valR[i][j] = red; 
        somR += red; 

        square_Red = red * red; 
        sum_Square_Red += square_Red; 

        valG[i][j] = green; 
        somG += green; 

        square_Green = green * green; 
        sum_Square_Green += square_Green; 

        valB[i][j] = blue; 
        somB += blue; 

        square_Blue = blue * blue; 
        sum_Square_Blue += square_Blue; 

       } 

      } 

      //la moyenne de pixels dechaque couleurs 
      meanR = somR/nbpixl; 
      meanG = somG/nbpixl; 
      meanB = somB/nbpixl; 
      //meanB = somB/nbpixl * 255.0f; 

      //1 method of calculating the variance 
      System.out.println("1 method of calculating the variance\n"); 
      float var[] = new float[3]; 
      for (int i = 0; i < h; i++) { 
       for (int j = 0; j < w; j++) { 

        varR += (meanR - valR[i][j]) * (meanR - valR[i][j]); 
        varG += (meanG - valG[i][j]) * (meanG - valG[i][j]); 
        varB += (meanR - valB[i][j]) * (meanB - valB[i][j]); 

       } 

      } 

      var[0] = (varR/nbpixl); 

      var[1] = (varG/nbpixl); 

      var[2] = (varB/nbpixl); 

      float var_img = ((var[0] + var[1] + var[2])/nbpixl); 

      System.out.println("var=\t"+var[0] + "\t"+ var[1] + "\t"+                 var[2]); 
      System.out.println("var of image=\t" + var_img); 

      //2 method of calculating the variance 
      System.out.println("2 method of calculating the variance\n"); 

      float varR1 = sum_Square_Red/nbpixl - (meanR * meanR); 
      float varG1 = sum_Square_Green/nbpixl - (meanG * meanG); 
      float varB1 = sum_Square_Blue/nbpixl - (meanB * meanB); 
      float mean_img1 = ((varR1 + varG1 + varB1)/nbpixl); 

     System.out.println("var=\t" + varR1 + "\t" + varG1 + "\t" + varB1); 
      System.out.println("var of image=\t" + mean_img1); 

     } 

    } catch (IOException ex) { 
     Logger.getLogger(var_img1.class.getName()).log(Level.SEVERE, null, ex); 
    } 
} 

Und für das Ergebnis der Bild 1

Breite, Höhe: 259, 194

1 Methode zur Berechnung der Varianz

Varr = 7598,217 varg = 5033,452 varB = 4910,8223

Var von Bild = 0,34913212

2 Methode der Varianzberechnungs

2 Verfahren zur Berechnung der Varianz

Varr = 7597,9395 varg = 5183,0 varB = 4994.0

Var Bild = 0.3537583

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Und für Bild 2

Breite, Höhe: 620, 349 1 Verfahren zur Berechnung der Varianz

Varr = 991,2626 varg = 1525,1627 varB = 1280,9857

var of image = 0.017549733

2 methode von calc ulating die Varianz

Varr = -52.462,875 Varg = -50.101,0 -50.592,0 varB =

var von image = -0,70780975

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Und hier sind die zwei Bilder, die ich image1 image

verwendet