Hi all, I am new to processing an I need help...
First of all I have to say that I am italian and I am sorry for my poor english so I hope you will understand my question.

I should convert the pixels of a grayscale image (I use only white and black, not intermediate colours) to binary numbers, 0 if the pixel is white and 1 if it is black and I should put these values ​​in some array. Suppose that the image is divided into rows and columns of pixels, the thing is pretty easy because with the function pixel() I can make an array of values ​​for each column. Instead I have to do a particular thing: assuming to have a round clock with an image in its own background, while the seconds hand moves, it takes the pixels in the image below and make up the array...
I have written this little sketch:

1. PImage img;
   float degree = 0; // holds the angle for rotation
   int counter = 0; // holds the steps for rotations
   
   void setup()
   {
     size(220, 220);
     img = loadImage("penguin.gif"); // loading the image
     imageMode(CENTER);
     smooth();
   }
   
   void draw()
   {
     background(255);
     translate(width / 2, height / 2);
     image(img,0,0);
     noFill();
     ellipse(0, 0, 200, 200);// transparent circle
     if(counter < 100)// I make 100 steps of 3.6 degree
     {
       degree += radians(3.6);
       rotate(degree);
       counter++;
     }
     rect(0,0,1,88); // clock hand that rotates every step
     // and now???
   

How I can assign the pixel in the background image to the rectangle? Is this the right way to solve my problem or there are better methods?
 
Thanks for your attention,
Roberto