Hi there, this is a new tutorial category in my blog. It’s Computer Vision. In this blog, I’d like to show you something cool. It’s how to perform Face Detection using your camera or Webcam. You’ll see how your application can detect faces from a captured image. Curious about it? Let’s take a look how to do that.
This what you need to follow this tutorial:
- Microsoft Visual Studio 2010. Or if you don’t have one, you can use 2008 version.
- Emgu CV (OpenCV in .NET). You can download the latest version in this link: www.emgu.com/wiki/index.php/Main_Page and follow the installation instruction.
- Basic Knowledge of C# Programming.
- Familiar in WPF Development.
After you’ve got what you need, it’s time to rock!
First thing you should do is installing Emgu CV. Your installation path should be like
C:\Emgu\emgucv-windows-x86 126.96.36.1990. And you can see inside
C:\Emgu\emgucv-windows-x86 188.8.131.520\bin some DLLs and sample programs. You can see a simple face detection app
Example.FaceDetection.exe and you’ll see something like the first picture in this post.
Next, let’s open your Visual Studio and create a new WPF Project. Add some references and make sure it’ll look like the picture below:
Now, copy code below to make our user experience. Put this code in your
Next, let’s code it! Open your
MainWindow.xaml.cs and add this code on top.
Initialize two objects
HaarCascade. Those are important class in this tutorial, so you have to make it. And we also need
DispatcherTimer to capture the picture every millisecond.
This last part is the routine. What this code will do is capture image every millisecond, and then convert it to gray frame. After converted, faces will be detected. Each detected faces will be marked by black rectangular.
Finally, this additional code is needed to convert plain
Bitmap class to
BitmapSource so WPF can read it as an image and view it on
Here is the result of our work:
Okay, I think that’s all I can do in this post. See you to my next post.
Note : If you can’t run your project, just build it and make sure all
opencv_xxxx.dll files and
haarcascade_frontalface_alt_tree.xml in the same directory with your executable file. You can find those files inside
If you’re interested in Computer Vision topic, not just limited to face detection, I suggest to read the latest book written by Dr. Adrian Kaehler and Dr. Gary Rost Bradski: Learning OpenCV 3 (or the older Learning OpenCV book published in 2008, which is cheaper in price but using the old API).
Even though the code samples are written in C/C++, you can easily transform it into C# with Emgu CV wrapper.