Tag: ComputerVision

I was hoping this would be a blog post about some wonderful stuff I was doing in OpenCV about detecting the location of soccer balls in video.. for the purpose of writing a robot that controls the Pan-Tilt-Zoom of the video camera to automatically follow the action in a soccer game so that I don’t have to (Lazy)

However, the program keeps hanging.

I started commenting out code to figure out what I was doing wrong.

Here’s the final version that hung:

using OpenCvSharp;
using OpenCvSharp.CPlusPlus;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace OpenCvTest
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                Console.WriteLine("Hey");
                //using (var cap = CvCapture.FromFile(@"00026.MTS"))
                //using (var cvWindow = new CvWindow("output"))
                //{
                //    var size = new Size(9, 9);
                //    while (CvWindow.WaitKey(10) < 0)
                //    {
                //        using (IplImage imgSrc = cap.QueryFrame()) 
                //        using (IplImage imgSmall = new IplImage(new Size(640, 480), BitDepth.U8, 1))
                //        using (IplImage imgGray = new IplImage(imgSmall.Size, BitDepth.U8, 1)) 
                //        {
                //            cvWindow.ShowImage(imgSrc);
                //            Cv.Resize(imgSrc, imgSmall);
                //            Cv.CvtColor(imgSmall, imgGray, ColorConversion.BgrToGray);
                //            Cv.Smooth(imgGray, imgGray, SmoothType.Gaussian, 9);
                //            using (CvMemStorage storage = new CvMemStorage())
                //            {
                //                CvSeq<CvCircleSegment> seq = imgGray.HoughCircles(storage, HoughCirclesMethod.Gradient, 1, 100, 150, 55, 0, 0);
                //                foreach (CvCircleSegment item in seq)
                //                {
                //                    imgGray.Circle(item.Center, (int)item.Radius, CvColor.Red, 3);
                //                }
                //                cvWindow.ShowImage(imgGray);
                //            } 
                //        }
                //    }
                //}
            }
            catch (Exception ex)
            {
                Console.Error.WriteLine(ex.Message);
            }
            finally
            {
                Console.WriteLine("Done");
            }

        }
    }
}

• If you look closely, you’ll realize that all the lines are commented out.    And it still hung.  
• 1 Reboot later:   Nope, still hanging.
• Remove references to OpenCV:   Still Hangs.
• Turns out if I run it without the debugger, its okay, but running it under the debugger, it hangs.

Well, La De Derp.   I don’t like it when things like Debugging don’t work.   Makes me .. trust things less.  Granted, this is Visual Studio Express.  But still!    Back to Console.WriteLine debugging for now…

Here’s some links to some code:

• Opens video file, and draws each frame with edge detection.   (pretty much straight from somebody’s example):  https://github.com/sunnywiz/openCvTest/blob/show-blackwhite-video/OpenCvTest/OpenCvTest/Program.cs
• Opens video file, and attempts to do circle detection (doesn’t find any): https://github.com/sunnywiz/openCvTest/blob/attempt-circle-detect/OpenCvTest/OpenCvTest/Program.cs

What I’ve learned:

• In the future, I’d probably use another library – EmguCV?   Seems more mature?  
• I might be able to use a <insert technical terms here> (other forms of detection – FAST something? BURPY something?  I remember not exactly) .. something which can use a single image to train from using 64 dimensional wavelets.  Woo.    Not today.
• I have not researched PTZ Apis
• I don’t have a solution for splitting the stream from capture to video and capture to ball detection
• I’m not sure about the easing functions that would be involved, there’s quite a delay from detection (if I ever do) to movement
• I’m not sure what to do with the ball kids playing with soccer balls at the sides of the field.