Could anyone help me with this code. I am trying to make the target follow the given colour. But it is not working>.<  Any help or suggestions?

import processing.video.*;
// Size of each cell in the grid
int cellSize = 8;
// Number of columns and rows in our system
int cols, rows;
// Variable for capture device
Capture video;

int firsttime = 0;
int numPixels;
int[] previousFrame;
int[] differenceFrame;

void setup() {
size(640, 480, P3D);
frameRate(30);
cols = width / cellSize;
rows = height / cellSize;
colorMode(RGB, 255, 255, 255, 100);
println(cols);
println(rows);

// Uses the default video input, see the reference if this causes an error
video = new Capture(this, cols, rows, 30);
numPixels = video.width * video.height;
// Create an array to store the previously captured frame
previousFrame = new int[numPixels];
differenceFrame = new int[numPixels];
loadPixels();

background(0);
}

void draw() {
float corx,  cory;
if (video.available()) {

  video.read(); // Read the new frame from the camera
  int colorX = 0; // X-coordinate of the closest in color video pixel
 int colorY = 0; // Y-coordinate of the closest in color video pixel

   float closestColor = 10000;
   
   int index = 0;
  video.loadPixels(); // Make its pixels[] array available
  if (firsttime < 10) {
    firsttime++;
    for (int i = 0; i < numPixels; i++) { // For each pixel in the video frame...
      previousFrame[i] = video.pixels[i];
    }
  }
 
  fill(color(255, 255, 255, 5));
  noStroke();
  rectMode(CORNER);    
  rect(0,0,width, height);
 
  int movementSum = 0; // Amount of movement in the frame
  for (int i = 0; i < numPixels; i++) { // For each pixel in the video frame...
    color currColor = video.pixels[i];
    color prevColor = previousFrame[i];
    // Extract the red, green, and blue components from current pixel
    int currR = (currColor >> 16) & 0xFF; // Like red(), but faster
    int currG = (currColor >> 8) & 0xFF;
    int currB = currColor & 0xFF;
    // Extract red, green, and blue components from previous pixel
    int prevR = (prevColor >> 16) & 0xFF;
    int prevG = (prevColor >> 8) & 0xFF;
    int prevB = prevColor & 0xFF;
    // Compute the difference of the red, green, and blue values
    int diffR = abs(currR - prevR);
    int diffG = abs(currG - prevG);
    int diffB = abs(currB - prevB);
    // Add these differences to the running tally
    movementSum += diffR + diffG + diffB;
   
    differenceFrame[i] = 0xff000000 | (diffR << 16) | (diffG << 8) | diffB;

    previousFrame[i] = currColor;
   

}
  if (movementSum >= 0) {
    for (int i = 0; i < cols; i++) {
      for (int j = 0; j < rows; j++) {
        int x = i*cellSize;
        int y = j*cellSize;
        int loc = (video.width - i - 1) + j*video.width; // Reversing x to mirror the image
       
        if ((brightness(differenceFrame[loc]) >= 20) && (brightness(previousFrame[loc]) < brightness(get(x+cellSize/2, y+cellSize/2)) )) {
          float r = red(video.pixels[loc]);
          float g = green(video.pixels[loc]);
          float b = blue(video.pixels[loc]);
          color c = color(r, g, b, 50);
          pushMatrix();
          translate(x+cellSize/2, y+cellSize/2);
          rotate((2 * PI * brightness(c) / 125.0));
          rectMode(CENTER);
          fill(c);
          //stroke(c);
          corx =0+random(-cellSize,cellSize);
          cory =0+random(-cellSize,cellSize);
         
          rect(corx, cory,
           corx+pow(brightness(differenceFrame[loc])/40,2)+cellSize, cory+ pow(brightness(differenceFrame[loc])/40,2)+cellSize);
          popMatrix();
   }
    if ((brightness(previousFrame[loc]) >= 20) && (brightness(differenceFrame[loc]) > brightness(get(x+cellSize/2, y+cellSize/2)) )) {
          float r = red(video.pixels[loc]);
          float g = green(video.pixels[loc]);
          float b = blue(video.pixels[loc]);
          color c = color(r, g, b, 50);
          pushMatrix();
          translate(x+cellSize/2, y+cellSize/2);
          rotate((2 * PI * brightness(c) / 125.0));
          rectMode(CENTER);
          fill(c);
          //stroke(c);
          corx =0+random(-cellSize,cellSize);
          cory =0+random(-cellSize,cellSize);
       
         
          ellipse(corx, cory,
           corx+pow(brightness(differenceFrame[loc])/40,2)+cellSize, cory+ pow(brightness(differenceFrame[loc])/40,2)+cellSize);
          popMatrix();
   }
  }
 }
  }
  if (movementSum > 0)
  {
    //updatePixels();
    println(movementSum); // Print the total amount of movement to the console
 
 
  for (int b = 0; b < video.height; b++) {
    for (int a = 0; a < video.width; a++) {
      // Get the color stored in the pixel
      int pixelValue = pixels[index];
      // Determine the brightness of the pixel
        float colorProximity = abs(red(pixelValue)-255)+abs(green(pixelValue)-0)+abs(blue(pixelValue)-0);
 

 
 if (colorProximity < closestColor) {
 closestColor = colorProximity;
 closestColor=closestColor-10; //thoguht behind this is that it once it "locks" on to an object of color, it wont let go unless something a good bit better (closer in color) comes along
 colorY = b;
 colorX = a;
   updatePixels();
      }
      index++;
    }
  }

}

smooth();
//----------------------------------------------------------Target
 stroke(0);
 strokeWeight(3);
 fill(255,0,0);
 ellipse(colorX,colorY,200,200);
 fill(255);
 ellipse(colorX,colorY,150,150);
 fill(255,0,0);
 ellipse(colorX, colorY, 100, 100);
 fill(255);
 ellipse(colorX,colorY,50,50);
}
}