faceData.QueryFaceByIndex(i); returns null reference

Mona_J_ · ‎05-31-2015

I am trying to run this code but I receive null reference from faceData.QueryFaceByIndex(i) or f.QueryPose(). Can you please help me figure out what's wrong? I have attached the whole project in zip format so you can be able to reproduce it.

//--------------------------------------------------------------------------------------
// Copyright 2014-2015 Intel Corporation
// All Rights Reserved
//
// Permission is granted to use, copy, distribute and prepare derivative works of this
// software for any purpose and without fee, provided, that the above copyright notice
// and this statement appear in all copies.  Intel makes no representations about the
// suitability of this software for any purpose.  THIS SOFTWARE IS PROVIDED "AS IS."
// INTEL SPECIFICALLY DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, AND ALL LIABILITY,
// INCLUDING CONSEQUENTIAL AND OTHER INDIRECT DAMAGES, FOR THE USE OF THIS SOFTWARE,
// INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PROPRIETARY RIGHTS, AND INCLUDING THE
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  Intel does not
// assume any responsibility for any errors which may appear in this software nor any
// responsibility to update it.
//--------------------------------------------------------------------------------------
using System;
using System.Windows;
using System.Windows.Media;
using System.Threading;
using System.Drawing;
using System.ComponentModel;

namespace HelloWorld
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private Thread processingThread;
        private PXCMSenseManager senseManager;
        private PXCMHandModule hand;
        private PXCMHandConfiguration handConfig;
        private PXCMHandData handData;
        private PXCMHandData.GestureData gestureData;
        private bool handWaving;
        private bool handTrigger;
        private int msgTimer;
 
        public MainWindow()
        {
            InitializeComponent();
            handWaving = false;
            handTrigger = false;
            msgTimer = 0;

            // Instantiate and initialize the SenseManager
            senseManager = PXCMSenseManager.CreateInstance();
            senseManager.EnableStream(PXCMCapture.StreamType.STREAM_TYPE_COLOR, 640, 480, 30);
            senseManager.EnableHand();
            senseManager.Init();

            // Configure the Hand Module
            hand = senseManager.QueryHand();
            handConfig = hand.CreateActiveConfiguration();
            handConfig.EnableGesture("wave");
            handConfig.EnableAllAlerts();
            handConfig.ApplyChanges();

            // Start the worker thread
            processingThread = new Thread(new ThreadStart(ProcessingThread));
            processingThread.Start();
        }
        
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            lblMessage.Content = "(Wave Your Hand)";
            Console.WriteLine("Waving and all");
            

        }

        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            processingThread.Abort();
            if (handData != null) handData.Dispose();
            handConfig.Dispose();
            senseManager.Dispose();
        }

        private void ProcessingThread()
        {
            // Start AcquireFrame/ReleaseFrame loop
            while (senseManager.AcquireFrame(true) >= pxcmStatus.PXCM_STATUS_NO_ERROR)
            {
                PXCMCapture.Sample sample = senseManager.QuerySample();
                Bitmap colorBitmap;
                PXCMImage.ImageData colorData;

                // Get color image data
                sample.color.AcquireAccess(PXCMImage.Access.ACCESS_READ, PXCMImage.PixelFormat.PIXEL_FORMAT_RGB24, out colorData);
                colorBitmap = colorData.ToBitmap(0, sample.color.info.width, sample.color.info.height);

                // Retrieve gesture data
                hand = senseManager.QueryHand();
                
                // Update the user interface
                UpdateUI(colorBitmap);
                senseManager.EnableFace();
                PXCMFaceModule faceModule = senseManager.QueryFace();
                PXCMFaceConfiguration faceConfig = faceModule.CreateActiveConfiguration();
                faceConfig.detection.isEnabled = true;
                faceConfig.detection.maxTrackedFaces = 2;
                faceConfig.landmarks.isEnabled = true;
                faceConfig.ApplyChanges();
                faceConfig.Dispose();
                
                Console.WriteLine("We got here!");
                PXCMFaceData faceData = faceModule.CreateOutput();
                faceData.Update();
                int numFaces = faceData.QueryNumberOfDetectedFaces();
                Console.WriteLine(numFaces);
                //PXCMFaceData.Face face = faceData.QueryFaceByIndex(0);

                for (int i = 0; i < numFaces; i++)  {
				  PXCMFaceData.Face f = faceData.QueryFaceByIndex(i);
				  PXCMFaceData.PoseData p = f.QueryPose();
				  PXCMPoint3DF32 outHeadPosition = new PXCMPoint3DF32();
                  
                 // Boolean headout= p.QueryHeadPosition(out outHeadPosition);
				 // p.QueryHeadPosition(out outHeadPosition);
				  //System.out.println("Out: " + outHeadPosition);
				  
				  PXCMFaceData.PoseEulerAngles outPoseEulerAngles = new PXCMFaceData.PoseEulerAngles();
				  p.QueryPoseAngles(out outPoseEulerAngles);
				  Console.WriteLine("Rotation: " + outPoseEulerAngles.roll + " " + outPoseEulerAngles.pitch + " " + outPoseEulerAngles.yaw);
				  
			  }



              //  PXCMFaceData.PoseData poseData = face.QueryPose();
              
                colorBitmap.Dispose();
                sample.color.ReleaseAccess(colorData);
                senseManager.ReleaseFrame();
            }
        }

        private void UpdateUI(Bitmap bitmap)
        {
            this.Dispatcher.Invoke(System.Windows.Threading.DispatcherPriority.Normal, new Action(delegate()
            {
                if (bitmap != null)
                {
                    // Mirror the color stream Image control
                    imgColorStream.RenderTransformOrigin = new System.Windows.Point(0.5, 0.5);
                    ScaleTransform mainTransform = new ScaleTransform();
                    mainTransform.ScaleX = -1;
                    mainTransform.ScaleY = 1;
                    imgColorStream.RenderTransform = mainTransform;
                    
                    // Display the color stream
                    imgColorStream.Source = ConvertBitmap.BitmapToBitmapSource(bitmap);

                    // Update the screen message
                    if (handWaving)
                    {
                        lblMessage.Content = "Hello World!";
                        handTrigger = true;
                    }

                    // Reset the screen message after ~50 frames
                    if (handTrigger)
                    {
                        msgTimer++;

                        if (msgTimer >= 50)
                        {
                            lblMessage.Content = "(Wave Your Hand)";
                            msgTimer = 0;
                            handTrigger = false;
                        }
                    }
                }
            }));
        }
    }
}

Mona_J_ · ‎05-31-2015

For some weird reason numFaces is always zero. So I don't know why is like so, I think that is why it can't query the face data. Any idea what's wrong with my code or say how to fix it? Because it gives null reference at this line

				  PXCMFaceData.PoseData p = f.QueryPose();

 PXCMFaceData faceData = faceModule.CreateOutput();
                faceData.Update();
                int numFaces = faceData.QueryNumberOfDetectedFaces();
                Console.WriteLine(numFaces);
                //PXCMFaceData.Face face = faceData.QueryFaceByIndex(0);

                //for (int i = 0; i < numFaces; i++)  {
                  Console.WriteLine("We got here!");
				  PXCMFaceData.Face f = faceData.QueryFaceByIndex(0);
                  Console.WriteLine("We got here too!");
				  PXCMFaceData.PoseData p = f.QueryPose();
				  PXCMPoint3DF32 outHeadPosition = new PXCMPoint3DF32();
                  
                 // Boolean headout= p.QueryHeadPosition(out outHeadPosition);
				 // p.QueryHeadPosition(out outHeadPosition);
				  //System.out.println("Out: " + outHeadPosition);

AndreCarlucci · ‎06-01-2015

Hi Mona,

Did you try calling "senseManager.EnableFace();" before calling "senseManager.Init();"?

Gal_G_Intel · ‎06-02-2015

Hey Mona, the issue I see here is that configuration should not be done every frame – preferably only once and before acquire frame processing loop

Init & Configuration
1. Enable face module -> senseManager.EnableFace();
2. Configure face module -> config.ApplyChanges();
3. Init -> senseManager.Init();
Processing
1. faceData->update();
2. Query faceData.

Let me know if you have any other problems.