tracker theo vật bằng webcam, dùng thư viện emguCV

[Thang_Hoang]

mình bị lỗi này mong các bạn giúp.
Đoạn code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.CV.UI;

namespace Tracker
{
public partial class Form1 : Form
{
//member varible
Capture capwebcam = null;
bool blnCapturingInProcess = false;
public Mat imgOriginal1;
Image<Bgr, Byte> imgOriginal;

Image<Gray, Byte> imgProcessed;

public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
try {
Capture capwebcam = new Capture(); //create a camera captue
// capwebcam = new Capture(Emgu.CV.CvEnum.CaptureType.DShow); ; // associate capture object to the defaut webcam
} catch (NullReferenceException except) { // catch error if unsucessful
//txtXY.Text = except.Message; // show error object message in text box
MessageBox.Show(except.Message);
return;
}
// wwhen we have a good capture object
Application.Idle += processFrameAndUpdateGUI; // add process image function to application;s list of tasks
blnCapturingInProcess = true;
}
private void Form1_FormClose(object sender, FormClosedEventArgs e)
{
if (capwebcam != null)
{
capwebcam.Dispose();
}
}
/////////////
void processFrameAndUpdateGUI(object sender, EventArgs arg)
{
imgOriginal1 = capwebcam.QueryFrame(); // get the next frame from the webcam
imgOriginal = imgOriginal1.ToImage<Bgr, byte>();

if (imgOriginal == null) return; // if we did not get a frame
imgProcessed = imgOriginal.InRange(new Bgr(0, 0, 175), // min filter value if color is greater than or equal to this
new Bgr(100, 100, 256)); // max filter value if color less than or equal to this
imgProcessed = imgProcessed.SmoothGaussian(9); // we call SmoothGaussian with only one param, that being the x ang y size of the filter window
CircleF[] circles = imgProcessed.HoughCircles(new Gray(100), //canny threshold
new Gray(50), // accumulator threshold
2, // size of image/this param = "accumulator resoltion
imgProcessed.Height / 4, // min distance in pixel between the centers of detected circles
10, // min radius of detected circles
400)[0]; // max radius of detected circle, get circle from the first channel
foreach (CircleF circle in circles)
{
if (txtXY.Text != "") txtXY.AppendText(Environment.NewLine); // if we are not on the first line in the text box, insert the new line char
txtXY.AppendText("ball position = x" + circle.Center.X.ToString().PadLeft(4) + // x position of center point of circle
", y = " + circle.Center.Y.ToString().PadLeft(4) + // y position of center point of circle
" radius = " + circle.Radius.ToString("###.000").PadLeft(7)); // radius circle
txtXY.ScrollToCaret(); //move the text box croll bar down to the line

// draw small green cirlce at the center of the detected object
// to do this , we will call opencv1.x function, this is nessesary
// we will draw radius 3, even though the size of the dectected circle will be much bigger
// the CVInvoke object can be used to make opencv1.x function calls

CvInvoke.Circle(imgOriginal, //draw on the original image
new Point((int)circle.Center.X, (int)circle.Center.Y), // center point of circle
3, // radius of circle
new MCvScalar(0, 255, 0), // draw pure green
-1, // thickness of the circle, -1 indicates to fill the circle
LineType.AntiAlias, // use AntiAlias to smooth the pixels
0); // no shift

// draw red circle around the detected oject
imgOriginal.Draw(circle,
new Bgr(Color.Red),
3); //thickness of the circle pixels
}
ibOriginal.Image = imgOriginal;
ibProcess.Image = imgProcessed;
}

private void btPauseandResume_Click(object sender, EventArgs e)
{
if (blnCapturingInProcess == true)
{
Application.Idle -= processFrameAndUpdateGUI;
blnCapturingInProcess = false;
btPauseandResume.Text = "resume";
}
else
{
Application.Idle += processFrameAndUpdateGUI;
blnCapturingInProcess = true;
btPauseandResume.Text = "pause";
}
}

private void btStart_Click(object sender, EventArgs e)
{
processFrameAndUpdateGUI(null ,null);
}

}
}