ext/opencv/gsthanddetect.cpp - mtk-gst-plugins-bad - Git at Google

 /*
  * GStreamer hand gesture detection plugins
  * Copyright (C) 2012 Andol Li <<andol@andol.info>>
  * Copyright (C) 2013 Sreerenj Balachandran <sreerenj.balachandran@intel.com>
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  *
  * Alternatively, the contents of this file may be used under the
  * GNU Lesser General Public License Version 2.1 (the "LGPL"), in
  * which case the following provisions apply instead of the ones
  * mentioned above:
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  * Boston, MA 02111-1307, USA.
  */
 /**
  * SECTION:video-filter-handdetect
  *
  * FIXME:operates hand gesture detection in video streams and images,
  * and enable media operation e.g. play/stop/fast forward/back rewind.
  *
  * <refsect2>
  * <title>Example launch line</title>
  * |[
  * gst-launch-1.0 autovideosrc ! videoconvert ! "video/x-raw, format=RGB, width=320, height=240" ! \
  * videoscale ! handdetect ! videoconvert ! xvimagesink
  * ]|
  * </refsect2>
  */

 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif

 /* element header */
 #include "gsthanddetect.h"
 #if (CV_MAJOR_VERSION >= 3)
 #include <opencv2/imgproc.hpp>
 #endif
 #include <opencv2/imgproc/imgproc_c.h>

 GST_DEBUG_CATEGORY_STATIC (gst_handdetect_debug);
 #define GST_CAT_DEFAULT gst_handdetect_debug

 /* define HAAR files */
 #define HAAR_FILE_FIST GST_HAAR_CASCADES_DIR G_DIR_SEPARATOR_S "fist.xml"
 #define HAAR_FILE_PALM GST_HAAR_CASCADES_DIR G_DIR_SEPARATOR_S "palm.xml"

 using namespace cv;
 using namespace std;
 /* Filter signals and args */
 enum
 {
   /* FILL ME */
   LAST_SIGNAL
 };

 enum
 {
   PROP_0,
   PROP_DISPLAY,
   PROP_PROFILE_FIST,
   PROP_PROFILE_PALM,
   PROP_ROI_X,
   PROP_ROI_Y,
   PROP_ROI_WIDTH,
   PROP_ROI_HEIGHT
 };

 /* the capabilities of the inputs and outputs */
 static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
     GST_PAD_SINK,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("RGB"))
     );
 static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
     GST_PAD_SRC,
     GST_PAD_ALWAYS,
     GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("RGB"))
     );

 static void gst_handdetect_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec);
 static void gst_handdetect_get_property (GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec);
 static gboolean gst_handdetect_set_caps (GstOpencvVideoFilter * transform,
     gint in_width, gint in_height, gint in_depth, gint in_channels,
     gint out_width, gint out_height, gint out_depth, gint out_channels);
 static GstFlowReturn gst_handdetect_transform_ip (GstOpencvVideoFilter *
     transform, GstBuffer * buffer, IplImage * img);

 static CascadeClassifier *gst_handdetect_load_profile (GstHanddetect * filter,
     gchar * profile);

 static void gst_handdetect_navigation_interface_init (GstNavigationInterface *
     iface);
 static void gst_handdetect_navigation_send_event (GstNavigation * navigation,
     GstStructure * structure);

 G_DEFINE_TYPE_WITH_CODE (GstHanddetect, gst_handdetect,
     GST_TYPE_OPENCV_VIDEO_FILTER,
     G_IMPLEMENT_INTERFACE (GST_TYPE_NAVIGATION,
         gst_handdetect_navigation_interface_init););

 static void
 gst_handdetect_navigation_interface_init (GstNavigationInterface * iface)
 {
   iface->send_event = gst_handdetect_navigation_send_event;
 }

 /* FIXME: this function used to parse the region of interests coordinates
  * sending from applications when the hand gestures reach the defined regions of interests,
  * at this moment this function is not doing anything significantly
  * but will be CHANGED when the gstreamer is patched with new hand gesture events
  */
 static void
 gst_handdetect_navigation_send_event (GstNavigation * navigation,
     GstStructure * structure)
 {
   GstHanddetect *filter = GST_HANDDETECT (navigation);
   GstPad *peer;

   if ((peer = gst_pad_get_peer (GST_BASE_TRANSFORM_CAST (filter)->sinkpad))) {
     GstEvent *event;
     event = gst_event_new_navigation (structure);
     gst_pad_send_event (peer, event);
     gst_object_unref (peer);
   }
 }

 /* clean opencv images and parameters */
 static void
 gst_handdetect_finalize (GObject * obj)
 {
   GstHanddetect *filter = GST_HANDDETECT (obj);

   if (filter->cvGray)
     cvReleaseImage (&filter->cvGray);
   g_free (filter->profile_fist);
   g_free (filter->profile_palm);
   delete (filter->best_r);

   G_OBJECT_CLASS (gst_handdetect_parent_class)->finalize (obj);
 }

 /* initialise the HANDDETECT class */
 static void
 gst_handdetect_class_init (GstHanddetectClass * klass)
 {
   GObjectClass *gobject_class;
   GstOpencvVideoFilterClass *gstopencvbasefilter_class;

   GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
   gobject_class = (GObjectClass *) klass;
   gstopencvbasefilter_class = (GstOpencvVideoFilterClass *) klass;

   gstopencvbasefilter_class->cv_trans_ip_func = gst_handdetect_transform_ip;
   gstopencvbasefilter_class->cv_set_caps = gst_handdetect_set_caps;

   gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_handdetect_finalize);
   gobject_class->set_property = gst_handdetect_set_property;
   gobject_class->get_property = gst_handdetect_get_property;

   g_object_class_install_property (gobject_class,
       PROP_DISPLAY,
       g_param_spec_boolean ("display",
           "Display",
           "Whether the detected hands are highlighted in output frame",
           TRUE, (GParamFlags)G_PARAM_READWRITE)
       );
   g_object_class_install_property (gobject_class,
       PROP_PROFILE_FIST,
       g_param_spec_string ("profile_fist",
           "Profile_fist",
           "Location of HAAR cascade file (fist gesture)",
           HAAR_FILE_FIST, (GParamFlags)G_PARAM_READWRITE)
       );
   g_object_class_install_property (gobject_class,
       PROP_PROFILE_PALM,
       g_param_spec_string ("profile_palm",
           "Profile_palm",
           "Location of HAAR cascade file (palm gesture)",
           HAAR_FILE_PALM, (GParamFlags)G_PARAM_READWRITE)
       );
   /* FIXME: property name needs fixing */
   g_object_class_install_property (gobject_class,
       PROP_ROI_X,
       g_param_spec_int ("ROI_X",
           "ROI_X",
           "X of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
           0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
       );
   /* FIXME: property name needs fixing */
   g_object_class_install_property (gobject_class,
       PROP_ROI_Y,
       g_param_spec_int ("ROI_Y",
           "ROI_Y",
           "Y of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
           0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
       );
   /* FIXME: property name needs fixing */
   g_object_class_install_property (gobject_class,
       PROP_ROI_WIDTH,
       g_param_spec_int ("ROI_WIDTH",
           "ROI_WIDTH",
           "WIDTH of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
           0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
       );
   /* FIXME: property name needs fixing */
   g_object_class_install_property (gobject_class,
       PROP_ROI_HEIGHT,
       g_param_spec_int ("ROI_HEIGHT",
           "ROI_HEIGHT",
           "HEIGHT of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
           0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
       );

   gst_element_class_set_static_metadata (element_class,
       "handdetect",
       "Filter/Effect/Video",
       "Performs hand gesture detection on videos, providing detected hand positions via bus message and navigation event, and deals with hand gesture events",
       "Andol Li <andol@andol.info>");

   gst_element_class_add_static_pad_template (element_class, &src_factory);
   gst_element_class_add_static_pad_template (element_class, &sink_factory);

 }

 /* initialise the new element
  * instantiate pads and add them to element
  * set pad call-back functions
  * initialise instance structure
  */
 static void
 gst_handdetect_init (GstHanddetect * filter)
 {
   const gchar *haar_path;

   haar_path = g_getenv ("GST_HAAR_CASCADES_PATH");
   if (haar_path) {
     filter->profile_fist = g_build_filename (haar_path, "fist.xml", NULL);
     filter->profile_palm = g_build_filename (haar_path, "palm.xml", NULL);
   } else {
     filter->profile_fist = g_strdup (HAAR_FILE_FIST);
     filter->profile_palm = g_strdup (HAAR_FILE_PALM);
   }

   filter->roi_x = 0;
   filter->roi_y = 0;
   filter->roi_width = 0;
   filter->roi_height = 0;
   filter->display = TRUE;

   filter->cvCascade_fist =
       gst_handdetect_load_profile (filter, filter->profile_fist);
   filter->cvCascade_palm =
       gst_handdetect_load_profile (filter, filter->profile_palm);

   gst_opencv_video_filter_set_in_place (GST_OPENCV_VIDEO_FILTER_CAST (filter),
       TRUE);
 }

 static void
 gst_handdetect_set_property (GObject * object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
   GstHanddetect *filter = GST_HANDDETECT (object);

   switch (prop_id) {
     case PROP_PROFILE_FIST:
       g_free (filter->profile_fist);
       if (filter->cvCascade_fist)
         delete filter->cvCascade_fist;
       filter->profile_fist = g_value_dup_string (value);
       filter->cvCascade_fist =
           gst_handdetect_load_profile (filter, filter->profile_fist);
       break;
     case PROP_PROFILE_PALM:
       g_free (filter->profile_palm);
       if (filter->cvCascade_palm)
         delete filter->cvCascade_palm;
       filter->profile_palm = g_value_dup_string (value);
       filter->cvCascade_palm =
           gst_handdetect_load_profile (filter, filter->profile_palm);
       break;
     case PROP_DISPLAY:
       filter->display = g_value_get_boolean (value);
       break;
     case PROP_ROI_X:
       filter->roi_x = g_value_get_int (value);
       break;
     case PROP_ROI_Y:
       filter->roi_y = g_value_get_int (value);
       break;
     case PROP_ROI_WIDTH:
       filter->roi_width = g_value_get_int (value);
       break;
     case PROP_ROI_HEIGHT:
       filter->roi_height = g_value_get_int (value);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 static void
 gst_handdetect_get_property (GObject * object, guint prop_id, GValue * value,
     GParamSpec * pspec)
 {
   GstHanddetect *filter = GST_HANDDETECT (object);

   switch (prop_id) {
     case PROP_DISPLAY:
       g_value_set_boolean (value, filter->display);
       break;
     case PROP_PROFILE_FIST:
       g_value_set_string (value, filter->profile_fist);
       break;
     case PROP_PROFILE_PALM:
       g_value_set_string (value, filter->profile_palm);
       break;
     case PROP_ROI_X:
       g_value_set_int (value, filter->roi_x);
       break;
     case PROP_ROI_Y:
       g_value_set_int (value, filter->roi_y);
       break;
     case PROP_ROI_WIDTH:
       g_value_set_int (value, filter->roi_width);
       break;
     case PROP_ROI_HEIGHT:
       g_value_set_int (value, filter->roi_height);
       break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
   }
 }

 /* GstElement vmethod implementations */
 /* this function handles the link with other elements */
 static gboolean
 gst_handdetect_set_caps (GstOpencvVideoFilter * transform,
     gint in_width, gint in_height, gint in_depth, gint in_channels,
     gint out_width, gint out_height, gint out_depth, gint out_channels)
 {
   GstHanddetect *filter;
   filter = GST_HANDDETECT (transform);

   /* 320 x 240 is with the best detect accuracy, if not, give info */
   if (in_width != 320 || in_height != 240)
     GST_WARNING_OBJECT (filter,
         "resize to 320 x 240 to have best detect accuracy.\n");

   if (filter->cvGray)
     cvReleaseImage (&filter->cvGray);
   filter->cvGray =
       cvCreateImage (cvSize (in_width, in_height), IPL_DEPTH_8U, 1);

   return TRUE;
 }

 /* Hand detection function
  * This function does the actual processing 'of hand detect and display'
  */
 static GstFlowReturn
 gst_handdetect_transform_ip (GstOpencvVideoFilter * transform,
     GstBuffer * buffer, IplImage * img)
 {
   GstHanddetect *filter = GST_HANDDETECT (transform);
   Rect *r;
   GstStructure *s;
   GstMessage *m;
   unsigned int i;
   vector < Rect > hands;

   /* check detection cascades */
   if (filter->cvCascade_fist && filter->cvCascade_palm) {
   /* cvt to gray colour space for hand detect */
     cvCvtColor (img, filter->cvGray, CV_RGB2GRAY);

     /* detect FIST gesture fist */
     Mat image = cvarrToMat(filter->cvGray);
     Mat roi (image, Rect (filter->cvGray->origin,
             filter->cvGray->origin, filter->cvGray->width,
             filter->cvGray->height));
     filter->cvCascade_fist->detectMultiScale (roi, hands, 1.1, 2,
         CV_HAAR_DO_CANNY_PRUNING, cvSize (24, 24), cvSize (0, 0));

     /* if FIST gesture detected */
     if (!hands.empty ()) {

       int min_distance, distance;
       Rect temp_r;
       CvPoint c;

       /* Go through all detected FIST gestures to get the best one
        * prev_r => previous hand
        * best_r => best hand in this frame
        */
       /* set min_distance for init comparison */
       min_distance = img->width + img->height;
       /* Init filter->prev_r */
       temp_r = Rect (0, 0, 0, 0);
       if (filter->prev_r == NULL)
         filter->prev_r = &temp_r;
       /* Get the best FIST gesture */
       for (i = 0; i < hands.size(); i++) {
         r = &hands[i];
         distance = (int) sqrt (pow ((r->x - filter->prev_r->x),
                 2) + pow ((r->y - filter->prev_r->y), 2));
         if (distance <= min_distance) {
           min_distance = distance;
           delete (filter->best_r);
           filter->best_r = new Rect (*r);
         }
       }
       /* Save best_r as prev_r for next frame comparison */
       filter->prev_r = filter->best_r;

       /* send msg to app/bus if the detected gesture falls in the region of interest */
       /* get center point of gesture */
       c = cvPoint (filter->best_r->x + filter->best_r->width / 2,
           filter->best_r->y + filter->best_r->height / 2);
       /* send message:
        * if the center point is in the region of interest, OR,
        * if the region of interest remains default as (0,0,0,0)*/
       if ((c.x >= filter->roi_x && c.x <= (filter->roi_x + filter->roi_width)
               && c.y >= filter->roi_y
               && c.y <= (filter->roi_y + filter->roi_height))
           || (filter->roi_x == 0
               && filter->roi_y == 0
               && filter->roi_width == 0 && filter->roi_height == 0)) {
         /* Define structure for message post */
         s = gst_structure_new ("hand-gesture",
             "gesture", G_TYPE_STRING, "fist",
             "x", G_TYPE_INT,
             (gint) (filter->best_r->x + filter->best_r->width * 0.5), "y",
             G_TYPE_INT,
             (gint) (filter->best_r->y + filter->best_r->height * 0.5), "width",
             G_TYPE_INT, (gint) filter->best_r->width, "height", G_TYPE_INT,
             (gint) filter->best_r->height, NULL);
         /* Init message element */
         m = gst_message_new_element (GST_OBJECT (filter), s);
         /* Send message */
         gst_element_post_message (GST_ELEMENT (filter), m);

 #if 0
         /* send event
          * here we use mouse-move event instead of fist-move or palm-move event
          * !!! this will CHANGE in the future !!!
          * !!! by adding gst_navigation_send_hand_detect_event() in navigation.c !!!
          */
         gst_navigation_send_mouse_event (GST_NAVIGATION (filter),
             "mouse-move",
             0,
             (double) (filter->best_r->x + filter->best_r->width * 0.5),
             (double) (filter->best_r->y + filter->best_r->height * 0.5));

 #endif
       }
       /* Check filter->display,
        * If TRUE, displaying red circle marker in the out frame */
       if (filter->display) {
         CvPoint center;
         int radius;
         center.x = cvRound ((filter->best_r->x + filter->best_r->width * 0.5));
         center.y = cvRound ((filter->best_r->y + filter->best_r->height * 0.5));
         radius =
             cvRound ((filter->best_r->width + filter->best_r->height) * 0.25);
         cvCircle (img, center, radius, CV_RGB (0, 0, 200), 1, 8, 0);
       }
     } else {
      /* if NO FIST gesture, detecting PALM gesture */
       filter->cvCascade_palm->detectMultiScale (roi, hands, 1.1, 2,
           CV_HAAR_DO_CANNY_PRUNING, cvSize (24, 24), cvSize (0, 0));
       /* if PALM detected */
       if (!hands.empty ()) {
         int min_distance, distance;
         Rect temp_r;
         CvPoint c;

         if (filter->display) {
           GST_DEBUG_OBJECT (filter, "%d PALM gestures detected\n",
               (int) hands.size ());
         }
         /* Go through all detected PALM gestures to get the best one
          * prev_r => previous hand
          * best_r => best hand in this frame
          */
         /* suppose a min_distance for init comparison */
         min_distance = img->width + img->height;
         /* Init filter->prev_r */
         temp_r = Rect (0, 0, 0, 0);
        if (filter->prev_r == NULL)
           filter->prev_r = &temp_r;
         /* Get the best PALM gesture */
         for (i = 0; i < hands.size (); ++i) {
           r = &hands[i];
           distance = (int) sqrt (pow ((r->x - filter->prev_r->x),
                   2) + pow ((r->y - filter->prev_r->y), 2));
           if (distance <= min_distance) {
             min_distance = distance;
             delete (filter->best_r);
             filter->best_r = new Rect (*r);
           }
         }
         /* Save best_r as prev_r for next frame comparison */
         filter->prev_r = filter->best_r;

         /* send msg to app/bus if the detected gesture falls in the region of interest */
         /* get center point of gesture */
         c = cvPoint (filter->best_r->x + filter->best_r->width / 2,
             filter->best_r->y + filter->best_r->height / 2);
         /* send message:
          * if the center point is in the region of interest, OR,
          * if the region of interest remains default as (0,0,0,0)*/
         if (((gint) c.x >= filter->roi_x
                 && (gint) c.x <= (filter->roi_x + filter->roi_width)
                 && (gint) c.y >= filter->roi_y
                 && (gint) c.y <= (filter->roi_y + filter->roi_height))
             || (filter->roi_x == 0 && filter->roi_y == 0
                 && filter->roi_width == 0 && filter->roi_height == 0)) {
           /* Define structure for message post */
           s = gst_structure_new ("hand-gesture",
               "gesture", G_TYPE_STRING, "palm",
               "x", G_TYPE_INT,
               (gint) (filter->best_r->x + filter->best_r->width * 0.5), "y",
               G_TYPE_INT,
               (gint) (filter->best_r->y + filter->best_r->height * 0.5),
               "width", G_TYPE_INT, (gint) filter->best_r->width, "height",
               G_TYPE_INT, (gint) filter->best_r->height, NULL);
           /* Init message element */
           m = gst_message_new_element (GST_OBJECT (filter), s);
           /* Send message */
           gst_element_post_message (GST_ELEMENT (filter), m);

 #if 0
           /* send event
            * here we use mouse-move event instead of fist-move or palm-move event
            * !!! this will CHANGE in the future !!!
            * !!! by adding gst_navigation_send_hand_detect_event() in navigation.c !!!
            */
           gst_navigation_send_mouse_event (GST_NAVIGATION (filter),
               "mouse-move",
               0,
               (double) (filter->best_r->x + filter->best_r->width * 0.5),
               (double) (filter->best_r->y + filter->best_r->height * 0.5));

           /* or use another way to send upstream navigation event for debug
            *
            * GstEvent *event =
            * gst_event_new_navigation (gst_structure_new
            * ("application/x-gst-navigation", "event", G_TYPE_STRING,
            * "mouse-move",
            * "button", G_TYPE_INT, 0,
            * "pointer_x", G_TYPE_DOUBLE,
            * (double) (filter->best_r->x + filter->best_r->width * 0.5),
            * "pointer_y", G_TYPE_DOUBLE,
            * (double) (filter->best_r->y + filter->best_r->height * 0.5),
            * NULL));
            * gst_pad_send_event (GST_BASE_TRANSFORM_CAST (filter)->srcpad, event);
            */
 #endif
         }
         /* Check filter->display,
          * If TRUE, displaying red circle marker in the out frame */
         if (filter->display) {
           CvPoint center;
           int radius;
           center.x =
               cvRound ((filter->best_r->x + filter->best_r->width * 0.5));
           center.y =
               cvRound ((filter->best_r->y + filter->best_r->height * 0.5));
           radius =
               cvRound ((filter->best_r->width + filter->best_r->height) * 0.25);
           cvCircle (img, center, radius, CV_RGB (0, 0, 200), 1, 8, 0);
         }
       }
     }
   }

   /* Push out the incoming buffer */
   return GST_FLOW_OK;
 }

 static CascadeClassifier *
 gst_handdetect_load_profile (GstHanddetect * filter, gchar * profile)
 {
   CascadeClassifier *cascade;

   cascade = new CascadeClassifier (profile);
   if (cascade->empty ()) {
     GST_ERROR_OBJECT (filter, "Invalid profile file: %s", profile);
     delete cascade;
     return NULL;
   }

   return cascade;
 }

 /* Entry point to initialize the plug-in
  * Initialize the plug-in itself
  * Register the element factories and other features
  */
 gboolean
 gst_handdetect_plugin_init (GstPlugin * plugin)
 {
   GST_DEBUG_CATEGORY_INIT (gst_handdetect_debug,
       "handdetect", 0, "opencv hand gesture detection");
   return gst_element_register (plugin, "handdetect", GST_RANK_NONE,
       GST_TYPE_HANDDETECT);
 }
	/*
	* GStreamer hand gesture detection plugins
	* Copyright (C) 2012 Andol Li <<andol@andol.info>>
	* Copyright (C) 2013 Sreerenj Balachandran <sreerenj.balachandran@intel.com>
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*
	* Alternatively, the contents of this file may be used under the
	* GNU Lesser General Public License Version 2.1 (the "LGPL"), in
	* which case the following provisions apply instead of the ones
	* mentioned above:
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public
	* License along with this library; if not, write to the
	* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	* Boston, MA 02111-1307, USA.
	*/
	/**
	* SECTION:video-filter-handdetect
	*
	* FIXME:operates hand gesture detection in video streams and images,
	* and enable media operation e.g. play/stop/fast forward/back rewind.
	*
	* <refsect2>
	* <title>Example launch line</title>
	* \|[
	* gst-launch-1.0 autovideosrc ! videoconvert ! "video/x-raw, format=RGB, width=320, height=240" ! \
	* videoscale ! handdetect ! videoconvert ! xvimagesink
	* ]\|
	* </refsect2>
	*/

	#ifdef HAVE_CONFIG_H
	#include <config.h>
	#endif

	/* element header */
	#include "gsthanddetect.h"
	#if (CV_MAJOR_VERSION >= 3)
	#include <opencv2/imgproc.hpp>
	#endif
	#include <opencv2/imgproc/imgproc_c.h>

	GST_DEBUG_CATEGORY_STATIC (gst_handdetect_debug);
	#define GST_CAT_DEFAULT gst_handdetect_debug

	/* define HAAR files */
	#define HAAR_FILE_FIST GST_HAAR_CASCADES_DIR G_DIR_SEPARATOR_S "fist.xml"
	#define HAAR_FILE_PALM GST_HAAR_CASCADES_DIR G_DIR_SEPARATOR_S "palm.xml"

	using namespace cv;
	using namespace std;
	/* Filter signals and args */
	enum
	{
	/* FILL ME */
	LAST_SIGNAL
	};

	enum
	{
	PROP_0,
	PROP_DISPLAY,
	PROP_PROFILE_FIST,
	PROP_PROFILE_PALM,
	PROP_ROI_X,
	PROP_ROI_Y,
	PROP_ROI_WIDTH,
	PROP_ROI_HEIGHT
	};

	/* the capabilities of the inputs and outputs */
	static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
	GST_PAD_SINK,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("RGB"))
	);
	static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
	GST_PAD_SRC,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS (GST_VIDEO_CAPS_MAKE ("RGB"))
	);

	static void gst_handdetect_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec);
	static void gst_handdetect_get_property (GObject * object, guint prop_id,
	GValue * value, GParamSpec * pspec);
	static gboolean gst_handdetect_set_caps (GstOpencvVideoFilter * transform,
	gint in_width, gint in_height, gint in_depth, gint in_channels,
	gint out_width, gint out_height, gint out_depth, gint out_channels);
	static GstFlowReturn gst_handdetect_transform_ip (GstOpencvVideoFilter *
	transform, GstBuffer * buffer, IplImage * img);

	static CascadeClassifier gst_handdetect_load_profile (GstHanddetect filter,
	gchar * profile);

	static void gst_handdetect_navigation_interface_init (GstNavigationInterface *
	iface);
	static void gst_handdetect_navigation_send_event (GstNavigation * navigation,
	GstStructure * structure);

	G_DEFINE_TYPE_WITH_CODE (GstHanddetect, gst_handdetect,
	GST_TYPE_OPENCV_VIDEO_FILTER,
	G_IMPLEMENT_INTERFACE (GST_TYPE_NAVIGATION,
	gst_handdetect_navigation_interface_init););

	static void
	gst_handdetect_navigation_interface_init (GstNavigationInterface * iface)
	{
	iface->send_event = gst_handdetect_navigation_send_event;
	}

	/* FIXME: this function used to parse the region of interests coordinates
	* sending from applications when the hand gestures reach the defined regions of interests,
	* at this moment this function is not doing anything significantly
	* but will be CHANGED when the gstreamer is patched with new hand gesture events
	*/
	static void
	gst_handdetect_navigation_send_event (GstNavigation * navigation,
	GstStructure * structure)
	{
	GstHanddetect *filter = GST_HANDDETECT (navigation);
	GstPad *peer;

	if ((peer = gst_pad_get_peer (GST_BASE_TRANSFORM_CAST (filter)->sinkpad))) {
	GstEvent *event;
	event = gst_event_new_navigation (structure);
	gst_pad_send_event (peer, event);
	gst_object_unref (peer);
	}
	}

	/* clean opencv images and parameters */
	static void
	gst_handdetect_finalize (GObject * obj)
	{
	GstHanddetect *filter = GST_HANDDETECT (obj);

	if (filter->cvGray)
	cvReleaseImage (&filter->cvGray);
	g_free (filter->profile_fist);
	g_free (filter->profile_palm);
	delete (filter->best_r);

	G_OBJECT_CLASS (gst_handdetect_parent_class)->finalize (obj);
	}

	/* initialise the HANDDETECT class */
	static void
	gst_handdetect_class_init (GstHanddetectClass * klass)
	{
	GObjectClass *gobject_class;
	GstOpencvVideoFilterClass *gstopencvbasefilter_class;

	GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
	gobject_class = (GObjectClass *) klass;
	gstopencvbasefilter_class = (GstOpencvVideoFilterClass *) klass;

	gstopencvbasefilter_class->cv_trans_ip_func = gst_handdetect_transform_ip;
	gstopencvbasefilter_class->cv_set_caps = gst_handdetect_set_caps;

	gobject_class->finalize = GST_DEBUG_FUNCPTR (gst_handdetect_finalize);
	gobject_class->set_property = gst_handdetect_set_property;
	gobject_class->get_property = gst_handdetect_get_property;

	g_object_class_install_property (gobject_class,
	PROP_DISPLAY,
	g_param_spec_boolean ("display",
	"Display",
	"Whether the detected hands are highlighted in output frame",
	TRUE, (GParamFlags)G_PARAM_READWRITE)
	);
	g_object_class_install_property (gobject_class,
	PROP_PROFILE_FIST,
	g_param_spec_string ("profile_fist",
	"Profile_fist",
	"Location of HAAR cascade file (fist gesture)",
	HAAR_FILE_FIST, (GParamFlags)G_PARAM_READWRITE)
	);
	g_object_class_install_property (gobject_class,
	PROP_PROFILE_PALM,
	g_param_spec_string ("profile_palm",
	"Profile_palm",
	"Location of HAAR cascade file (palm gesture)",
	HAAR_FILE_PALM, (GParamFlags)G_PARAM_READWRITE)
	);
	/* FIXME: property name needs fixing */
	g_object_class_install_property (gobject_class,
	PROP_ROI_X,
	g_param_spec_int ("ROI_X",
	"ROI_X",
	"X of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
	0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
	);
	/* FIXME: property name needs fixing */
	g_object_class_install_property (gobject_class,
	PROP_ROI_Y,
	g_param_spec_int ("ROI_Y",
	"ROI_Y",
	"Y of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
	0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
	);
	/* FIXME: property name needs fixing */
	g_object_class_install_property (gobject_class,
	PROP_ROI_WIDTH,
	g_param_spec_int ("ROI_WIDTH",
	"ROI_WIDTH",
	"WIDTH of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
	0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
	);
	/* FIXME: property name needs fixing */
	g_object_class_install_property (gobject_class,
	PROP_ROI_HEIGHT,
	g_param_spec_int ("ROI_HEIGHT",
	"ROI_HEIGHT",
	"HEIGHT of left-top pointer in region of interest \nGestures in the defined region of interest will emit messages",
	0, INT_MAX, 0, (GParamFlags)G_PARAM_READWRITE)
	);

	gst_element_class_set_static_metadata (element_class,
	"handdetect",
	"Filter/Effect/Video",
	"Performs hand gesture detection on videos, providing detected hand positions via bus message and navigation event, and deals with hand gesture events",
	"Andol Li <andol@andol.info>");

	gst_element_class_add_static_pad_template (element_class, &src_factory);
	gst_element_class_add_static_pad_template (element_class, &sink_factory);

	}

	/* initialise the new element
	* instantiate pads and add them to element
	* set pad call-back functions
	* initialise instance structure
	*/
	static void
	gst_handdetect_init (GstHanddetect * filter)
	{
	const gchar *haar_path;

	haar_path = g_getenv ("GST_HAAR_CASCADES_PATH");
	if (haar_path) {
	filter->profile_fist = g_build_filename (haar_path, "fist.xml", NULL);
	filter->profile_palm = g_build_filename (haar_path, "palm.xml", NULL);
	} else {
	filter->profile_fist = g_strdup (HAAR_FILE_FIST);
	filter->profile_palm = g_strdup (HAAR_FILE_PALM);
	}

	filter->roi_x = 0;
	filter->roi_y = 0;
	filter->roi_width = 0;
	filter->roi_height = 0;
	filter->display = TRUE;

	filter->cvCascade_fist =
	gst_handdetect_load_profile (filter, filter->profile_fist);
	filter->cvCascade_palm =
	gst_handdetect_load_profile (filter, filter->profile_palm);

	gst_opencv_video_filter_set_in_place (GST_OPENCV_VIDEO_FILTER_CAST (filter),
	TRUE);
	}

	static void
	gst_handdetect_set_property (GObject * object, guint prop_id,
	const GValue * value, GParamSpec * pspec)
	{
	GstHanddetect *filter = GST_HANDDETECT (object);

	switch (prop_id) {
	case PROP_PROFILE_FIST:
	g_free (filter->profile_fist);
	if (filter->cvCascade_fist)
	delete filter->cvCascade_fist;
	filter->profile_fist = g_value_dup_string (value);
	filter->cvCascade_fist =
	gst_handdetect_load_profile (filter, filter->profile_fist);
	break;
	case PROP_PROFILE_PALM:
	g_free (filter->profile_palm);
	if (filter->cvCascade_palm)
	delete filter->cvCascade_palm;
	filter->profile_palm = g_value_dup_string (value);
	filter->cvCascade_palm =
	gst_handdetect_load_profile (filter, filter->profile_palm);
	break;
	case PROP_DISPLAY:
	filter->display = g_value_get_boolean (value);
	break;
	case PROP_ROI_X:
	filter->roi_x = g_value_get_int (value);
	break;
	case PROP_ROI_Y:
	filter->roi_y = g_value_get_int (value);
	break;
	case PROP_ROI_WIDTH:
	filter->roi_width = g_value_get_int (value);
	break;
	case PROP_ROI_HEIGHT:
	filter->roi_height = g_value_get_int (value);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	static void
	gst_handdetect_get_property (GObject * object, guint prop_id, GValue * value,
	GParamSpec * pspec)
	{
	GstHanddetect *filter = GST_HANDDETECT (object);

	switch (prop_id) {
	case PROP_DISPLAY:
	g_value_set_boolean (value, filter->display);
	break;
	case PROP_PROFILE_FIST:
	g_value_set_string (value, filter->profile_fist);
	break;
	case PROP_PROFILE_PALM:
	g_value_set_string (value, filter->profile_palm);
	break;
	case PROP_ROI_X:
	g_value_set_int (value, filter->roi_x);
	break;
	case PROP_ROI_Y:
	g_value_set_int (value, filter->roi_y);
	break;
	case PROP_ROI_WIDTH:
	g_value_set_int (value, filter->roi_width);
	break;
	case PROP_ROI_HEIGHT:
	g_value_set_int (value, filter->roi_height);
	break;
	default:
	G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
	break;
	}
	}

	/* GstElement vmethod implementations */
	/* this function handles the link with other elements */
	static gboolean
	gst_handdetect_set_caps (GstOpencvVideoFilter * transform,
	gint in_width, gint in_height, gint in_depth, gint in_channels,
	gint out_width, gint out_height, gint out_depth, gint out_channels)
	{
	GstHanddetect *filter;
	filter = GST_HANDDETECT (transform);

	/* 320 x 240 is with the best detect accuracy, if not, give info */
	if (in_width != 320 \|\| in_height != 240)
	GST_WARNING_OBJECT (filter,
	"resize to 320 x 240 to have best detect accuracy.\n");

	if (filter->cvGray)
	cvReleaseImage (&filter->cvGray);
	filter->cvGray =
	cvCreateImage (cvSize (in_width, in_height), IPL_DEPTH_8U, 1);

	return TRUE;
	}

	/* Hand detection function
	* This function does the actual processing 'of hand detect and display'
	*/
	static GstFlowReturn
	gst_handdetect_transform_ip (GstOpencvVideoFilter * transform,
	GstBuffer * buffer, IplImage * img)
	{
	GstHanddetect *filter = GST_HANDDETECT (transform);
	Rect *r;
	GstStructure *s;
	GstMessage *m;
	unsigned int i;
	vector < Rect > hands;

	/* check detection cascades */
	if (filter->cvCascade_fist && filter->cvCascade_palm) {
	/* cvt to gray colour space for hand detect */
	cvCvtColor (img, filter->cvGray, CV_RGB2GRAY);

	/* detect FIST gesture fist */
	Mat image = cvarrToMat(filter->cvGray);
	Mat roi (image, Rect (filter->cvGray->origin,
	filter->cvGray->origin, filter->cvGray->width,
	filter->cvGray->height));
	filter->cvCascade_fist->detectMultiScale (roi, hands, 1.1, 2,
	CV_HAAR_DO_CANNY_PRUNING, cvSize (24, 24), cvSize (0, 0));

	/* if FIST gesture detected */
	if (!hands.empty ()) {

	int min_distance, distance;
	Rect temp_r;
	CvPoint c;

	/* Go through all detected FIST gestures to get the best one
	* prev_r => previous hand
	* best_r => best hand in this frame
	*/
	/* set min_distance for init comparison */
	min_distance = img->width + img->height;
	/* Init filter->prev_r */
	temp_r = Rect (0, 0, 0, 0);
	if (filter->prev_r == NULL)
	filter->prev_r = &temp_r;
	/* Get the best FIST gesture */
	for (i = 0; i < hands.size(); i++) {
	r = &hands[i];
	distance = (int) sqrt (pow ((r->x - filter->prev_r->x),
	2) + pow ((r->y - filter->prev_r->y), 2));
	if (distance <= min_distance) {
	min_distance = distance;
	delete (filter->best_r);
	filter->best_r = new Rect (*r);
	}
	}
	/* Save best_r as prev_r for next frame comparison */
	filter->prev_r = filter->best_r;

	/* send msg to app/bus if the detected gesture falls in the region of interest */
	/* get center point of gesture */
	c = cvPoint (filter->best_r->x + filter->best_r->width / 2,
	filter->best_r->y + filter->best_r->height / 2);
	/* send message:
	* if the center point is in the region of interest, OR,
	* if the region of interest remains default as (0,0,0,0)*/
	if ((c.x >= filter->roi_x && c.x <= (filter->roi_x + filter->roi_width)
	&& c.y >= filter->roi_y
	&& c.y <= (filter->roi_y + filter->roi_height))
	\|\| (filter->roi_x == 0
	&& filter->roi_y == 0
	&& filter->roi_width == 0 && filter->roi_height == 0)) {
	/* Define structure for message post */
	s = gst_structure_new ("hand-gesture",
	"gesture", G_TYPE_STRING, "fist",
	"x", G_TYPE_INT,
	(gint) (filter->best_r->x + filter->best_r->width * 0.5), "y",
	G_TYPE_INT,
	(gint) (filter->best_r->y + filter->best_r->height * 0.5), "width",
	G_TYPE_INT, (gint) filter->best_r->width, "height", G_TYPE_INT,
	(gint) filter->best_r->height, NULL);
	/* Init message element */
	m = gst_message_new_element (GST_OBJECT (filter), s);
	/* Send message */
	gst_element_post_message (GST_ELEMENT (filter), m);

	#if 0
	/* send event
	* here we use mouse-move event instead of fist-move or palm-move event
	* !!! this will CHANGE in the future !!!
	* !!! by adding gst_navigation_send_hand_detect_event() in navigation.c !!!
	*/
	gst_navigation_send_mouse_event (GST_NAVIGATION (filter),
	"mouse-move",
	0,
	(double) (filter->best_r->x + filter->best_r->width * 0.5),
	(double) (filter->best_r->y + filter->best_r->height * 0.5));

	#endif
	}
	/* Check filter->display,
	* If TRUE, displaying red circle marker in the out frame */
	if (filter->display) {
	CvPoint center;
	int radius;
	center.x = cvRound ((filter->best_r->x + filter->best_r->width * 0.5));
	center.y = cvRound ((filter->best_r->y + filter->best_r->height * 0.5));
	radius =
	cvRound ((filter->best_r->width + filter->best_r->height) * 0.25);
	cvCircle (img, center, radius, CV_RGB (0, 0, 200), 1, 8, 0);
	}
	} else {
	/* if NO FIST gesture, detecting PALM gesture */
	filter->cvCascade_palm->detectMultiScale (roi, hands, 1.1, 2,
	CV_HAAR_DO_CANNY_PRUNING, cvSize (24, 24), cvSize (0, 0));
	/* if PALM detected */
	if (!hands.empty ()) {
	int min_distance, distance;
	Rect temp_r;
	CvPoint c;

	if (filter->display) {
	GST_DEBUG_OBJECT (filter, "%d PALM gestures detected\n",
	(int) hands.size ());
	}
	/* Go through all detected PALM gestures to get the best one
	* prev_r => previous hand
	* best_r => best hand in this frame
	*/
	/* suppose a min_distance for init comparison */
	min_distance = img->width + img->height;
	/* Init filter->prev_r */
	temp_r = Rect (0, 0, 0, 0);
	if (filter->prev_r == NULL)
	filter->prev_r = &temp_r;
	/* Get the best PALM gesture */
	for (i = 0; i < hands.size (); ++i) {
	r = &hands[i];
	distance = (int) sqrt (pow ((r->x - filter->prev_r->x),
	2) + pow ((r->y - filter->prev_r->y), 2));
	if (distance <= min_distance) {
	min_distance = distance;
	delete (filter->best_r);
	filter->best_r = new Rect (*r);
	}
	}
	/* Save best_r as prev_r for next frame comparison */
	filter->prev_r = filter->best_r;

	/* send msg to app/bus if the detected gesture falls in the region of interest */
	/* get center point of gesture */
	c = cvPoint (filter->best_r->x + filter->best_r->width / 2,
	filter->best_r->y + filter->best_r->height / 2);
	/* send message:
	* if the center point is in the region of interest, OR,
	* if the region of interest remains default as (0,0,0,0)*/
	if (((gint) c.x >= filter->roi_x
	&& (gint) c.x <= (filter->roi_x + filter->roi_width)
	&& (gint) c.y >= filter->roi_y
	&& (gint) c.y <= (filter->roi_y + filter->roi_height))
	\|\| (filter->roi_x == 0 && filter->roi_y == 0
	&& filter->roi_width == 0 && filter->roi_height == 0)) {
	/* Define structure for message post */
	s = gst_structure_new ("hand-gesture",
	"gesture", G_TYPE_STRING, "palm",
	"x", G_TYPE_INT,
	(gint) (filter->best_r->x + filter->best_r->width * 0.5), "y",
	G_TYPE_INT,
	(gint) (filter->best_r->y + filter->best_r->height * 0.5),
	"width", G_TYPE_INT, (gint) filter->best_r->width, "height",
	G_TYPE_INT, (gint) filter->best_r->height, NULL);
	/* Init message element */
	m = gst_message_new_element (GST_OBJECT (filter), s);
	/* Send message */
	gst_element_post_message (GST_ELEMENT (filter), m);

	#if 0
	/* send event
	* here we use mouse-move event instead of fist-move or palm-move event
	* !!! this will CHANGE in the future !!!
	* !!! by adding gst_navigation_send_hand_detect_event() in navigation.c !!!
	*/
	gst_navigation_send_mouse_event (GST_NAVIGATION (filter),
	"mouse-move",
	0,
	(double) (filter->best_r->x + filter->best_r->width * 0.5),
	(double) (filter->best_r->y + filter->best_r->height * 0.5));

	/* or use another way to send upstream navigation event for debug
	*
	* GstEvent *event =
	* gst_event_new_navigation (gst_structure_new
	* ("application/x-gst-navigation", "event", G_TYPE_STRING,
	* "mouse-move",
	* "button", G_TYPE_INT, 0,
	* "pointer_x", G_TYPE_DOUBLE,
	* (double) (filter->best_r->x + filter->best_r->width * 0.5),
	* "pointer_y", G_TYPE_DOUBLE,
	* (double) (filter->best_r->y + filter->best_r->height * 0.5),
	* NULL));
	* gst_pad_send_event (GST_BASE_TRANSFORM_CAST (filter)->srcpad, event);
	*/
	#endif
	}
	/* Check filter->display,
	* If TRUE, displaying red circle marker in the out frame */
	if (filter->display) {
	CvPoint center;
	int radius;
	center.x =
	cvRound ((filter->best_r->x + filter->best_r->width * 0.5));
	center.y =
	cvRound ((filter->best_r->y + filter->best_r->height * 0.5));
	radius =
	cvRound ((filter->best_r->width + filter->best_r->height) * 0.25);
	cvCircle (img, center, radius, CV_RGB (0, 0, 200), 1, 8, 0);
	}
	}
	}
	}

	/* Push out the incoming buffer */
	return GST_FLOW_OK;
	}

	static CascadeClassifier *
	gst_handdetect_load_profile (GstHanddetect * filter, gchar * profile)
	{
	CascadeClassifier *cascade;

	cascade = new CascadeClassifier (profile);
	if (cascade->empty ()) {
	GST_ERROR_OBJECT (filter, "Invalid profile file: %s", profile);
	delete cascade;
	return NULL;
	}

	return cascade;
	}

	/* Entry point to initialize the plug-in
	* Initialize the plug-in itself
	* Register the element factories and other features
	*/
	gboolean
	gst_handdetect_plugin_init (GstPlugin * plugin)
	{
	GST_DEBUG_CATEGORY_INIT (gst_handdetect_debug,
	"handdetect", 0, "opencv hand gesture detection");
	return gst_element_register (plugin, "handdetect", GST_RANK_NONE,
	GST_TYPE_HANDDETECT);
	}