// Learning Processing
// Daniel Shiffman
// http://www.learningprocessing.com
// Example 16-13: Simple motion detection
import processing.video.*;
// Variable for capture device
Capture video;
// Previous Frame
PImage prevFrame;
// How different must a pixel be to be a "motion" pixel
float threshold = 50;
void setup() {
size(320,240);
video = new Capture(this, width, height, 30);
// Create an empty image the same size as the video
prevFrame = createImage(video.width,video.height,RGB);
}
void draw() {
// Capture video
if (video.available()) {
// Save previous frame for motion detection!!
prevFrame.copy(video,0,0,video.width,video.height,0,0,video.width,video.height); // Before we read the new frame, we always save the previous frame for comparison!
prevFrame.updatePixels();
video.read();
}
loadPixels();
video.loadPixels();
prevFrame.loadPixels();
// Begin loop to walk through every pixel
for (int x = 0; x < video.width; x ++ ) {
for (int y = 0; y < video.height; y ++ ) {
int loc = x + y*video.width; // Step 1, what is the 1D pixel location
color current = video.pixels[loc]; // Step 2, what is the current color
color previous = prevFrame.pixels[loc]; // Step 3, what is the previous color
// Step 4, compare colors (previous vs. current)
float r1 = red(current); float g1 = green(current); float b1 = blue(current);
float r2 = red(previous); float g2 = green(previous); float b2 = blue(previous);
float diff = dist(r1,g1,b1,r2,g2,b2);
// Step 5, How different are the colors?
// If the color at that pixel has changed, then there is motion at that pixel.
if (diff > threshold) {
// If motion, display black
pixels[loc] = color(0);
} else {
// If not, display white
pixels[loc] = color(255);
}
}
}
updatePixels();
}
