Hi,

New to processing, new here...
It's probably a really stupid question but I read all the related topics in this forum and didn't found an answer.

I have just installed OpenCV library and I jus wanted to see how the face recognition works,
but I think something is wrong with my webcam recognition or compatibility.

When I open the example 'Face_detection' and run it without making any changes
the screen goes gray and the webcam led is still off.

Windows 7 64 bits, OpenCV 1, Processing 1.5, Webcam listed as [0] "Integrated Webcam-WDM"


So the face_detection original code is:

1. import hypermedia.video.*;
   import java.awt.Rectangle;
   
   
   OpenCV opencv;
   
   // contrast/brightness values
   int contrast_value    = 0;
   int brightness_value  = 0;
   
   
   
   void setup() {
   
       size( 320, 240 );
   
       opencv = new OpenCV( this );
       opencv.capture( width, height );                   // open video stream
       opencv.cascade( OpenCV.CASCADE_FRONTALFACE_ALT );  // load detection description, here-> front face detection : "haarcascade_frontalface_alt.xml"
   
   
       // print usage
       println( "Drag mouse on X-axis inside this sketch window to change contrast" );
       println( "Drag mouse on Y-axis inside this sketch window to change brightness" );
   
   }
   
   
   public void stop() {
       opencv.stop();
       super.stop();
   }
   
   
   
   void draw() {
   
       // grab a new frame
       // and convert to gray
       opencv.read();
       opencv.convert( GRAY );
       opencv.contrast( contrast_value );
       opencv.brightness( brightness_value );
   
       // proceed detection
       Rectangle[] faces = opencv.detect( 1.2, 2, OpenCV.HAAR_DO_CANNY_PRUNING, 40, 40 );
   
       // display the image
       image( opencv.image(), 0, 0 );
   
       // draw face area(s)
       noFill();
       stroke(255,0,0);
       for( int i=0; i<faces.length; i++ ) {
           rect( faces[i].x, faces[i].y, faces[i].width, faces[i].height );
       }
   }
   
   
   
   /**
    * Changes contrast/brigthness values
    */
   void mouseDragged() {
       contrast_value   = (int) map( mouseX, 0, width, -128, 128 );
       brightness_value = (int) map( mouseY, 0, width, -128, 128 );
   }
   

When I run the applet it shows the following message:

NullPointerException:

Error while starting capture : device 0
Drag mouse on X-axis inside this sketch window to change contrast
Drag mouse on Y-axis inside this sketch window to change brightness
OpenCV could not define source dimensions.

Exception in thread "Animation Thread" java.lang.NullPointerException
    at processing.core.PGraphics.image(Unknown Source)
    at processing.core.PApplet.image(Unknown Source)
    at face_detection.draw(face_detection.java:71)
    at processing.core.PApplet.handleDraw(Unknown Source)
    at processing.core.PApplet.run(Unknown Source)
    at java.lang.Thread.run(Thread.java:662)



Does any body know what I'm missing?

Thanks in advance!