How to read videocapture using dotimaging

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C#

image-recognition

, +

I try to read a sequence of images to do some process. I don't have any error but when I run it the program stop and gives the error "An unhandled exception of type 'System.AggregateException' occurred in mscorlib.dll" and told me that frame is null...I searched about DotImaging but I didn't find anything useful for fixing the error in my code.

What I have tried:

private void button1_Click(object sender, EventArgs e)
        {
            Bgr<byte>[,] frame = null;
            string videoDir = "C:\\pic\\Sequence of mypic";
            videoCapture = new ImageDirectoryCapture(videoDir, "*.jpg");
           
                videoCapture.Open();

                videoCapture.ReadTo(ref frame);
               if (frame == null)
                return;

            videoCapture.Seek(-1, SeekOrigin.Current);

            if (isROISelected)
            {
                
                Application.Idle -= videoCapture_InitFrame;
                Application.Idle += videoCapture_NewFrame;
            }
            else
            {
                frame.Draw(roi, Bgr<byte>.Blue, 3);
            }
            this.pictureBox.Image = frame.ToBitmap(); 

            GC.Collect();
        }