OpenCV MacRuby

face.rb

framework 'AppKit'
class AppDelegate
  def applicationDidFinishLaunching(notification)
	opencv = OpenCV.new
	opencv.setup
	loop { opencv.trackFace; sleep 1 }
  end
end

app = NSApplication.sharedApplication
app.delegate = AppDelegate.new

window = NSWindow.alloc.initWithContentRect([200, 300, 300, 100],
    styleMask:NSTitledWindowMask|NSClosableWindowMask|NSMiniaturizableWindowMask,
    backing:NSBackingStoreBuffered,
    defer:false)
window.title      = 'FaceTracker'
window.level      = NSModalPanelWindowLevel
window.delegate   = app.delegate

window.display
window.orderFrontRegardless
app.run

OpenCV.h

#import <Cocoa/Cocoa.h>

#import "opencv2/imgproc/imgproc_c.h"
#import "opencv2/highgui/highgui_c.h"
#import "opencv2/objdetect/objdetect.hpp"


@interface OpenCV : NSObject {
	int scale;
	CvCapture* camera;
	CvHaarClassifierCascade* cascade;
	CvMemStorage* storage;
	
	IplImage *  current_frame;
	IplImage *  gray_image;
	IplImage *  small_image;
}

@end

OpenCV.m

#import "OpenCV.h"

@implementation OpenCV

- (void) setup
{
  scale = 4;

  camera = cvCreateCameraCapture (CV_CAP_ANY);
    cascade = (CvHaarClassifierCascade*) cvLoad ("/Users/jeff/Desktop/haar.xml", 0, 0, 0);
  storage = cvCreateMemStorage(0);

  current_frame = cvQueryFrame (camera);
    gray_image    = cvCreateImage(cvSize (current_frame->width, current_frame->height), IPL_DEPTH_8U, 1);
    small_image   = cvCreateImage(cvSize (current_frame->width / scale, current_frame->height / scale), IPL_DEPTH_8U, 1);
}


-(void) trackFace
{
  current_frame = cvQueryFrame(camera);
  cvCvtColor (current_frame, gray_image, CV_BGR2GRAY);
  cvResize (gray_image, small_image, CV_INTER_LINEAR);

  // cvHaarDetectObjects seems to kill the webcam stream somehow --the app runs
  // and the webcam stays on without it--,  without leaving any output in the
  // log whatsoever. It simply turns off the green webcam light and warns the
  // log that the webcam is gone:
  //
  //   WARNING: Couldn't grab new frame from camera!!!

  CvSeq* faces = cvHaarDetectObjects (small_image, cascade, storage,
                                      1.1, 2, CV_HAAR_DO_CANNY_PRUNING,
                                      cvSize (0, 0), cvSize (0, 0));

  int i;
  for (i = 0; i < (faces ? faces->total : 0); i++)
  {
    CvRect* r = (CvRect*) cvGetSeqElem (faces, i);
    printf("r->x: %d\n", r->x);
    printf("r->y: %d\n", r->y);
  }
}
@end