Robotics

Society of Computational Science & Robot Vision: Follow the Leader

Shawn Weisfeld — Tue, 09 Feb 2010 11:22:23 GMT

While working on my Masters at FIT I wrote a paper about some vision processing that I did with Microsoft Robotics Studio (http://msdn.microsoft.com/en-us/robotics/default.aspx) and and iRobot Create (http://store.irobot.com/shop/index.jsp?categoryId=3311368). I was asked if I would post it on a new website that one of my colleagues at FIT is putting together Society of Computational Science (http://www.societycomputationalscience.org). I thought I would also take the opportunity to post it here (http://cid-80ce78240aa8df49.skydrive.live.com/self.aspx/.Public/RobotShawnWeisfeld.pdf), as I loose anything that is not on my blog. . . .

Here is a picture of my robot and I at a presentation that I did at the Orlando Bar Camp a few years back.

First Robotics Dallas Regional 2009

sweisfeld — Sun, 15 Mar 2009 16:35:00 GMT

     My day job is one of the sponsors of the First Robotics Program. The idea behind the program is to get kids interested in technology. I was invited to participate in the Dallas Regional where high schools from all over the south west and even Mexico participated in a competition to build and deploy a robot to play a game called Lunacy. You can read more about First Robotics here (http://www.usfirst.org) and more about the Dallas Regional here (http://dallas.txfirst.org/).
     Lockheed sponsored something called 5th Gear. This was a simulator built on XNA that allowed the teams to practice the strategy playing Lunacy without wear and tear on their robots. You can get a copy of 5th Gear and practice yourself here (http://www.tinyurl.com/5thgear).
     My task at the event was to stream and capture the video. The organizers had a team that took video and displayed it in the venue but they wanted the ability to share the event LIVE online. Additionally they wanted the ability to record the video so that the teams could watch it later.
     Streaming was done via UStream.tv. This is a free service that has a flash plug-in that allows you to broadcast LIVE video to the internet. This allowed parents, classmates back home, family, and the world to see what was going on at the event. Attendance in the online broadcast fluctuated but we had over 7000 people logged in watching the event. To capture the video we used the Pinnacle Systems - Studio MovieBox Plus (http://www.bestbuy.com/site/olspage.jsp?skuId=8983816&st=pinnacle&lp=9&type=product&cp=1&id=1218004430057).
     Recording was done using the Pinnacle - Video Transfer (http://www.bestbuy.com/site/olspage.jsp?skuId=8719032&st=pinnacle&lp=8&type=product&cp=1&id=1200702767761). This allowed us to capture high quality video direct to a hard drive (i.e. without a computer). We then used the included software to chop up the videos by match. Due to concerns over the length and size of the videos we chose to upload the clips to Veoh. We chose that service again because it was free and because YouTube and MSN Soapbox have size/length limitations. The videos have/will be uploaded here (http://www.veoh.com/search/videos/q/publisher:DallasFirst#).
     All in all this was a great experience. The only way this country is going to say a leader in the world is if we get the next generation interested in science and technology. Programs like this are a great step in that direction. I would like to thanks the folks at First and my company for sponsoring this event.

Using the CCR for Line of Business Applications

sweisfeld — Tue, 08 Jan 2008 18:09:00 GMT

For fun I have been playing around with Microsoft Robotics studio (http://microsoft.com/robotics) for a long time now and I have listened to Microsoft’s George Chrysanthakopoulos tell us how cool the CCR was in just about every webcast. Well I have decided to see if I can use the CCR in a regular business application and eliminate some of the pains of writing multithreaded code.

To that end I started with a simple problem, calculating Fibonacci numbers, and like any good developer I started with an easy to implement sequential algorithm. Now that I could sequentially calculate the numbers I wanted to see if I can use the CCR to calculate the same results. This required creation of a new execute method, but note that I was able to reuse the code that I wrote to calculate 1 Fibonacci number, the only thing I am rewriting is the test harness. Finally I rewrote the code using a traditional threading model.

Calculating 10 Fibonacci numbers sequentially took about 13.7 seconds on my dual core laptop, but as one would expect only one of my cores was actually working the other one just sat there doing nothing. On the other hand when processing the same set of numbers with both the CCR or the traditional threading model it took about 7.3 seconds. This is due to the fact that now I was able to use both cores of my computer.

I know what you are saying, self, why use the CCR I could just use traditional threading techniques. IMHO the major benefit you get with the use of the CCR is that the delta between the sequential code you write and the CCR enabled code you write is much smaller.

The CCR makes heavy use of queuing logic. So when you have work to be performed you just shove it in a queue and attach a receive arbiter to tell the CCR what to do with each work item (message). The CCR takes care of all the plumbing required to schedule and coordinate each item.

When starting to work with the CCR I strongly recommend reading the following articles. All of witch I have shamelessly borrowed ideas from.

MSDN CCR User Guide (http://msdn2.microsoft.com/en-us/library/bb905447.aspx)
Jeffrey Richter’s MSDN article (http://msdn.microsoft.com/msdnmag/issues/06/09/concurrentaffairs/default.aspx)
Nick’s Blog (http://iodyne.blogspot.com/search/label/CCR)

The Code

This is my entry point where I generate some random numbers and then pass them to each of the test harnesses to get processed.

    1             //Generate random number to calculate Fibonacci for
    2             int[] fibonacciCalculations = new int[10];
    3             Random r = new Random();
    4             for(int i = 0; i < fibonacciCalculations.Length; i++)
    5             {
    6                 fibonacciCalculations[i] = r.Next(30, 40);
    7             }
    8 
    9             SequentialExample.Execute(fibonacciCalculations);
   10             ThreadPoolExample.Execute(fibonacciCalculations);
   11             CcrExample.Execute(fibonacciCalculations);
   12 
   13             Console.WriteLine("Done!");
   14             Console.ReadKey();

Sequential Test Harness

    1     /// <summary>
    2     /// Method used to exercise the sequential algorithm
    3     /// </summary>
    4     public class SequentialExample
    5     {
    6         public static void Execute(int[] fibonacciCalculations)
    7         {
    8             DateTime start = DateTime.Now;
    9 
   10             //iterate over the collection, calculate and display the results
   11             for (int i = 0; i < fibonacciCalculations.Length; i++)
   12             {
   13                 SequentialFibonacci f = new SequentialFibonacci(fibonacciCalculations[i]);
   14                 f.Calculate();
   15                 Console.WriteLine("Answer: {0}", f.FibOfN);
   16             }
   17 
   18             //Display the execution time
   19             TimeSpan runtime = DateTime.Now.Subtract(start);
   20             Console.WriteLine("Sequential in {0} milliseconds.", runtime.TotalMilliseconds);
   21         }
   22     }
   23 
   24     /// <summary>
   25     /// Calculate a given Fibonacci number
   26     /// </summary>
   27     public class SequentialFibonacci
   28     {
   29         /// <summary>
   30         /// Default constructor
   31         /// </summary>
   32         /// <param name="n"></param>
   33         public SequentialFibonacci(int n)
   34         {
   35             _n = n;
   36         }
   37 
   38         /// <summary>
   39         /// Recursive method that calculates the Nth Fibonacci number.
   40         /// </summary>
   41         /// <param name="n"></param>
   42         /// <returns></returns>
   43         private int Calculate(int n)
   44         {
   45             if (n <= 1)
   46             {
   47                 return n;
   48             }
   49 
   50             return Calculate(n - 1) + Calculate(n - 2);
   51         }
   52 
   53         /// <summary>
   54         /// Calculate the fibonacci number for me
   55         /// </summary>
   56         public void Calculate()
   57         {
   58             _fibOfN = Calculate(_n);
   59         }
   60 
   61         public int N { get { return _n; } }
   62         private int _n;
   63 
   64         public int FibOfN { get { return _fibOfN; } }
   65         private int _fibOfN;
   66     }

CCR Test Harness

    1 public class CcrExample
    2     {
    3         public static void Execute(int[] fibonacciCalculations)
    4         {
    5             DateTime start = DateTime.Now;
    6 
    7             //Create the queues
    8             DispatcherQueue dq = new DispatcherQueue();
    9             Port<SequentialFibonacci> fibPort = new Port<SequentialFibonacci>();
   10             SuccessFailurePort results = new SuccessFailurePort();
   11 
   12             //Post the work to be completed
   13             for (int i = 0; i < fibonacciCalculations.Length; i++)
   14             {
   15                 fibPort.Post(new SequentialFibonacci(fibonacciCalculations[i]));
   16             }
   17 
   18             //Tell the CCR how to proccess each work item 
   19             //(scatter the work over avaiable workers)
   20             Arbiter.Activate(dq, 
   21                 Arbiter.Receive(true, fibPort,
   22                 delegate(SequentialFibonacci fib)
   23                 {
   24                     try
   25                     {
   26                         fib.Calculate();
   27                         Console.WriteLine("Answer: {0}", fib.FibOfN);
   28                         results.Post(new SuccessResult());
   29                     }
   30                     catch (Exception ex)
   31                     {
   32                         results.Post(ex);
   33                     }
   34                 }));
   35 
   36             //Tell the CCR to wait tell us when it is done
   37             //(Gather up all the results)
   38             Arbiter.Activate(dq,
   39                 Arbiter.MultipleItemReceive(results, fibonacciCalculations.Length,
   40                 delegate(ICollection<SuccessResult> successes, ICollection<Exception> failures)
   41                 {
   42                     TimeSpan runtime = DateTime.Now.Subtract(start);
   43                     Console.WriteLine("CCR in {0} milliseconds.", runtime.TotalMilliseconds);
   44                 }));
   45         }
   46 
   47     }

Thread Pool Test Harness

    1     /// <summary>
    2     /// Excerpt from How to: Use a Thread Pool (C# Programming Guide)
    3     /// http://msdn2.microsoft.com/en-us/library/3dasc8as(VS.80).aspx
    4     /// </summary>
    5     public class ThreadedFibonacci
    6     {
    7         public ThreadedFibonacci(int n, ManualResetEvent doneEvent)
    8         {
    9             _n = n;
   10             _doneEvent = doneEvent;
   11         }
   12 
   13         // Wrapper method for use with thread pool.
   14         public void ThreadPoolCallback(Object threadContext)
   15         {
   16             int threadIndex = (int)threadContext;
   17             _fibOfN = Calculate(_n);
   18             Console.WriteLine("Answer: {0}", _fibOfN);
   19             _doneEvent.Set();
   20         }
   21 
   22         // Recursive method that calculates the Nth Fibonacci number.
   23         public int Calculate(int n)
   24         {
   25             if (n <= 1)
   26             {
   27                 return n;
   28             }
   29 
   30             return Calculate(n - 1) + Calculate(n - 2);
   31         }
   32 
   33         public int N { get { return _n; } }
   34         private int _n;
   35 
   36         public int FibOfN { get { return _fibOfN; } }
   37         private int _fibOfN;
   38 
   39         private ManualResetEvent _doneEvent;
   40     }
   41 
   42     public class ThreadPoolExample
   43     {
   44         public static void Execute(int[] fibonacciCalculations)
   45         {
   46             DateTime start = DateTime.Now;
   47 
   48             // One event is used for each Fibonacci object
   49             ManualResetEvent[] doneEvents = new ManualResetEvent[fibonacciCalculations.Length];
   50             ThreadedFibonacci[] fibArray = new ThreadedFibonacci[fibonacciCalculations.Length];
   51 
   52             // Configure and launch threads using ThreadPool:
   53             for (int i = 0; i < fibonacciCalculations.Length; i++)
   54             {
   55                 doneEvents[i] = new ManualResetEvent(false);
   56                 ThreadedFibonacci f = new ThreadedFibonacci(fibonacciCalculations[i], doneEvents[i]);
   57                 fibArray[i] = f;
   58                 ThreadPool.QueueUserWorkItem(f.ThreadPoolCallback, i);
   59             }
   60 
   61             // Wait for all threads in pool to calculation...
   62             WaitHandle.WaitAll(doneEvents);
   63 
   64             TimeSpan runtime = DateTime.Now.Subtract(start);
   65             Console.WriteLine("Threaded in {0} milliseconds.", runtime.TotalMilliseconds);
   66 
   67         }
   68     }

Central Florida Tech Fair

sweisfeld — Sun, 07 Oct 2007 17:59:00 GMT

Here you can download my presentations from the CFL Tech Fair.

http://onetug.net/Documents/CFL_Presentations.zip

BarCamp Orlando

sweisfeld — Sun, 23 Sep 2007 06:16:00 GMT

Here is the powerpoint (http://www.onetug.org/DNN/Portals/0/member_files/2007_09_23_BarCamp.ppt) for the presentation that I plan on doing Sunday at BarCamp Orlando. See you there!
In the presenation I will provide an overview of MS Robotics Studio, and then provide 4 demo’s.
Demo #1: iRobot Drive by wire
Demo #2: Physics Simulation
Demo #3: Can you find me?
Demo #4: Robot Sumo!
All the demo’s are avaiable to download along with the MS Robotics Studio from the Microsoft Website http://www.microsoft.com/robotics

Tallahasse Code Camp

sweisfeld — Sat, 22 Sep 2007 22:28:00 GMT

Although it was a bit of a drive, Tallahassee Code Camp was great. I have included both presenations and the sample code in the attached zip file.
http://www.onetug.org/DNN/Portals/0/member_files/2007_09_22_TalCodeCamp.zip

Image Processing v2.1

sweisfeld — Tue, 18 Sep 2007 00:35:00 GMT

BTW to convert from the byte[] back to an image is simple enough

private Bitmap ConvertBitmap(byte[] frame, int width, int height)
{
Bitmap bmp = new Bitmap(
width,
height,
PixelFormat.Format24bppRgb);

BitmapData data = bmp.LockBits(
new Rectangle(0, 0, bmp.Width, bmp.Height),
ImageLockMode.WriteOnly,
PixelFormat.Format24bppRgb);

System.Runtime.InteropServices.Marshal.Copy(frame, 0, data.Scan0, frame.Length);

bmp.UnlockBits(data);
return bmp;
}

Image Processing v2

sweisfeld — Mon, 17 Sep 2007 22:47:00 GMT

I was tearing into v1.5 of Microsoft Robotics Studio (http://www.microsoft.com/robotics) and came across a novel way to process the pixels in an image. In previous posts I was using unmanaged C# code and pointers to move around the image. This worked well but is hard to manage. They take the approach of just dumping the entire image to a byte[], pure genius, now why did I not think of that. I will be rebuilding my library to utilize this technique but I thought this was so cool that I just had to share it!

/// <summary>
/// Coverts a bitmap to a byte[] then prints out the contents to a file
/// </summary>
public void PrintImage()
{
    string file = "image.bmp";
    Bitmap bitmap = Bitmap.FromFile(file) as Bitmap;
    byte[] frame = ConvertBitmap(bitmap);
    int height = bitmap.Height;
    int width = bitmap.Width;

    using (StreamWriter sWriter = new StreamWriter(file + ".txt"))
    {
        int offset;

//header
sWriter.WriteLine(string.Format("({0}, {1}) {2},{3},{4}", "COL", "ROW", "RED", "GREEN", "BLUE"));

        //loop over rows
        for (int y = 0; y < height; y++)
        {
            offset = y * width * 3;

            //loop ober columns
            for (int x = 0; x < width; x++, offset += 3)
            {
                int r, g, b;

                b = frame[offset];
                g = frame[offset + 1];
                r = frame[offset + 2];

                //pixel information
                sWriter.WriteLine(string.Format("({0}, {1}) {2},{3},{4}", x, y, r, g, b));
            }
        }
    }
}

/// <summary>
/// Convert a bitmap to a byte array
/// </summary>
/// <param name="bitmap">image to convert</param>
/// <returns>image as bytes</returns>
private byte[] ConvertBitmap(Bitmap bitmap)
{
    //Code excerpted from Microsoft Robotics Studio v1.5
    BitmapData raw = null; //used to get attributes of the image
    byte[] rawImage = null; //the image as a byte[]

    try
    {
        //Freeze the image in memory
        raw = bitmap.LockBits(
            new Rectangle(0, 0, (int)bitmap.Width, (int)bitmap.Height),
            ImageLockMode.ReadOnly,
            PixelFormat.Format24bppRgb
        );

int size = raw.Height * raw.Stride;
rawImage = new byte[size];

        //Copy the image into the byte[]
        System.Runtime.InteropServices.Marshal.Copy(raw.Scan0, rawImage, 0, size);
    }
    finally
    {
        if (raw != null)
        {
            //Unfreeze the memory for the image
            bitmap.UnlockBits(raw);
        }
    }
    return rawImage;
}

Jax CodeCamp Presentations

sweisfeld — Sun, 26 Aug 2007 19:09:00 GMT

Here are my two presentations from the Jax CodeCamp.

OOP
http://www.onetug.org/sf/Files/MemberFiles/JaxCcWeisfeldShawnOOP.ppt

Robot Vision
http://www.onetug.org/sf/Files/MemberFiles/JaxCcWeisfeldShawnRobotVision.ppt

Tampa Code Camp Robot Vision Presentation

sweisfeld — Sat, 14 Jul 2007 08:35:00 GMT

Here is the powerpoint for my presentation tomorrow.

http://www.onetug.org/DNN/Portals/0/member_files/2007_07_14_robot.ppt