Blob tracking
Now that you know how to apply a thresholding algorithm on a webcam feed, it's time to do some analysis on those pixels. We'll draw a rectangle around all white pixels in the image. This is a very basic brightness tracking algorithm and is useful when you want to create a simple interactive installation with a webcam.
How to do it...
We'll start by importing the video library and declaring some variables. We need a Capture object to access the webcam and an integer variable to use as a threshold value. The other integer variables are used to track the boundaries around the white pixels in the image.
import processing.video.*;
Capture webcam;
int threshold;
int topLeftX;
int topLeftY;
int bottomRightX;
int bottomRightY;
void setup()
{
size( 640, 480 );
webcam = new Capture( this, width, height, 30);
webcam.start();
threshold = 127;
topLeftX = width;
topLeftY = height;
bottomRightX = 0;
bottomRightY = 0;
}Inside the draw() function, we'll apply the...