Question

任何人都可以帮助我使用EmguCv C＃从webcamera实时更新直方图框中的直方图。

HistogramBox hb = new HistogramBox();
Form frm = new Form();

hb.GenerateHistograms(img, 256);// show 256 shades
hb.Enabled = true;

hb.Size = new System.Drawing.Size(255, 255);// change to your preferred size 
frm.Controls.Add(hb);
hb.Refresh();   

frm.ShowDialog();

这是我得到的片段，但是当我包含在webcamera捕获方法中时，对话框会刷新，使其变为空白而不是更新。

using System.Windows.Forms;
using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using Emgu.CV.UI;
namespace Redcolor_tracker_GUI
{
    public partial class Form1 : Form
    {
        Capture capWebcam = null;
        bool inProcess = false;
        Image<Bgr, Byte> img;
        Image<Gray, Byte> imgout;
        HistogramBox hb = new HistogramBox();
        bool toggle = false;
        Form frm = new Form();

        public Form1()
        {
            InitializeComponent();


        }



        private void Form1_Load(object sender, EventArgs e)
        {
            try
            {
                capWebcam = new Capture();
            }
            catch (NullReferenceException except)
            {
                txtXYRadius.Text = except.Message;
                return;
            }
            Application.Idle += processFrameGUI;
            inProcess = true;


        }
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            if (capWebcam != null)
            {
                capWebcam.Dispose();
            }
        }
        void processFrameGUI(object sender,EventArgs srg)
        {
            img=capWebcam.QueryFrame();
            if(img==null) return;
            imgout=img.InRange(new Bgr(0,0,0),new Bgr(0,0,0));
            imgout=imgout.SmoothGaussian(9);
            if (toggle)
            {

              hb.GenerateHistograms(img, 256);
              hb.Refresh();// show 256 shades
              hb.Enabled = true;

             }
            ibOriginal.Image=img;
            ibProcessed.Image=imgout;
         }

        private void btnPauseOResume_Click(object sender, EventArgs e)
        {
            if (inProcess == true)
            {
                Application.Idle -= processFrameGUI;
                inProcess = false;
                btnPauseOrResume.Text = "resume";
            }
            else
            {
                Application.Idle += processFrameGUI;
                inProcess = true;
                btnPauseOrResume.Text = "resume";
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (toggle == false)
            {
                toggle = true;
            }
            else
            {
                toggle = false;
            }

            hb.Size = new System.Drawing.Size(400, 400);

            frm.Controls.Add(hb);
            frm.ShowDialog();  
        }

    }
}

完整的代码******************

谢谢

Answer 1

您可以通过在定义的时间间隔内调用HistogramBox方法（例如，使用计时器）来更新单独工作线程中的Refresh控件。请注意，您应该通过引用其SyncContext将刷新调用封送到UI线程中。

示例：

//Runs on a worker Thread this.Invoke((MethodInvoker)delegate { hb.Refresh();; // Runs on UI thread });

Answer 2

尝试在ClearHistogram()内调用processFrameGUI(object sender,EventArgs srg)：

void processFrameGUI(object sender,EventArgs srg)
{
    img=capWebcam.QueryFrame();
    if(img==null) return;
    imgout=img.InRange(new Bgr(0,0,0),new Bgr(0,0,0));
    imgout=imgout.SmoothGaussian(9);
    if (toggle)
    {
      // Note the following line:
      hb.ClearHistogram();
      hb.GenerateHistograms(img, 256);
      hb.Refresh();// show 256 shades
      hb.Enabled = true;

     }
    ibOriginal.Image=img;
    ibProcessed.Image=imgout;
 }

如何在EmguCV C＃中实时刷新webcamera的直方图？

2 个答案: