Calibrate works?

lib/video/examples/Capture/BackgroundSubtraction/BackgroundSubtraction.pde

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+/**
+ * Background Subtraction 
+ * by Golan Levin. 
+ *
+ * Detect the presence of people and objects in the frame using a simple
+ * background-subtraction technique. To initialize the background, press a key.
+ */
+
+
+import processing.video.*;
+
+int numPixels;
+int[] backgroundPixels;
+Capture video;
+
+void setup() {
+  size(640, 480); 
+  
+  // This the default video input, see the GettingStartedCapture 
+  // example if it creates an error
+  //video = new Capture(this, 160, 120);
+  video = new Capture(this, width, height);
+  
+  // Start capturing the images from the camera
+  video.start();  
+  
+  numPixels = video.width * video.height;
+  // Create array to store the background image
+  backgroundPixels = new int[numPixels];
+  // Make the pixels[] array available for direct manipulation
+  loadPixels();
+}
+
+void draw() {
+  if (video.available()) {
+    video.read(); // Read a new video frame
+    video.loadPixels(); // Make the pixels of video available
+    // Difference between the current frame and the stored background
+    int presenceSum = 0;
+    for (int i = 0; i < numPixels; i++) { // For each pixel in the video frame...
+      // Fetch the current color in that location, and also the color
+      // of the background in that spot
+      color currColor = video.pixels[i];
+      color bkgdColor = backgroundPixels[i];
+      // Extract the red, green, and blue components of the current pixel's color
+      int currR = (currColor >> 16) & 0xFF;
+      int currG = (currColor >> 8) & 0xFF;
+      int currB = currColor & 0xFF;
+      // Extract the red, green, and blue components of the background pixel's color
+      int bkgdR = (bkgdColor >> 16) & 0xFF;
+      int bkgdG = (bkgdColor >> 8) & 0xFF;
+      int bkgdB = bkgdColor & 0xFF;
+      // Compute the difference of the red, green, and blue values
+      int diffR = abs(currR - bkgdR);
+      int diffG = abs(currG - bkgdG);
+      int diffB = abs(currB - bkgdB);
+      // Add these differences to the running tally
+      presenceSum += diffR + diffG + diffB;
+      // Render the difference image to the screen
+      pixels[i] = color(diffR, diffG, diffB);
+      // The following line does the same thing much faster, but is more technical
+      //pixels[i] = 0xFF000000 | (diffR << 16) | (diffG << 8) | diffB;
+    }
+    updatePixels(); // Notify that the pixels[] array has changed
+    println(presenceSum); // Print out the total amount of movement
+  }
+}
+
+// When a key is pressed, capture the background image into the backgroundPixels
+// buffer, by copying each of the current frame's pixels into it.
+void keyPressed() {
+  video.loadPixels();
+  arraycopy(video.pixels, backgroundPixels);
+}