ROS package wrapping OpenCV's face detection cascade. It provides a ROS node that subscribes to an image topic and publishes the following topics:

/pal_face/faces
/pal_face/debug

The /pal_face/faces topic contains a pal_detection_msgs/FaceDetections message with the regions of interest classified as faces. The /pal_face/debug is an image topic with the faces detected painted on it.

In one terminal play the rosbag provided in the package:

rosbag play `rospack find pal_face_detector_opencv`/etc/two_faces.bag --loop

In another terminal launch the detector:

roslaunch pal_face_detector_opencv detector.launch

In a third terminal, run the following command to see the face detections in the video stream:

rosrun image_view image_view image:=/pal_face/debug

An example of the /pal_face/debug topic image is shown below