Tutorial
Wrapping OpenCV
Function Mapping - Emgu.CV.CvInvoke
The CvInvoke class provides a way to directly invoke OpenCV function within .NET languages. Each method in this class corresponds to a function in OpenCV of the same name. For example, a call to
IntPtr image = CvInvoke.cvCreateImage(new System.Drawing.Size(400, 300), CvEnum.IPL_DEPTH.IPL_DEPTH_8U, 1);
is equivalent to the following function call in C
IplImage* image = cvCreateImage(cvSize(400, 300), IPL_DEPTH_8U, 1);
Both of which create a 400x300 of 8-bit unsigned grayscale image.
Structure Mapping - Emgu.CV.Structure.Mxxx
This type of structure is a direct mapping to OpenCV structures.
| Emgu CV Structure | OpenCV structure |
|---|---|
| Emgu.CV.Structure.MIplImage | IplImage |
| Emgu.CV.Structure.MCvMat | CvMat |
| ... | ... |
| Emgu.CV.Structure.Mxxxx | xxxx |
The prefix M here stands for Managed structure.
Emgu CV also borrows some existing structures in .Net to represent structures in OpenCV:
| .Net Structure | OpenCV structure |
|---|---|
| System.Drawing.Point | CvPoint |
| System.Drawing.PointF | CvPoint2D32f |
| System.Drawing.Size | CvSize |
| System.Drawing.Rectangle | CvRect |
Enumeration Mapping - Emgu.CV.CvEnum
The CvEnum namespace provides direct mapping to OpenCV enumerations. For example, CvEnum.IPL_DEPTH.IPL_DEPTH_8U has the same value as IPL_DEPTH_8U in OpenCV; both of which equals 8.
Managed classes
Working with Images
Working with Matrices
Error Handling
Emgu CV register a custom error handler in OpenCV. When error is encountered from OpenCV, a CvException will be thrown.
Code Documentation
Xml Documentation
Documentation is embedded in the code using xml format, which can then be compiled as HTML documentation using Sandcastle. You can browse our Online Documentation for the latest stable and development code.
Intellisense in Visual Studio
If you are using Visual Studio as your development tools, you will have intellisense support when developing Emgu CV applications. For example, if you want to create an image directly using cvCreateImage function, which is wrapped by the CvInvoke Class, just type CvInvoke.
and a list of functions belonging to CvInvoke class is displayed along with a description for each of the functions. Since you are creating an image, select the cvCreateImage function
The list of parameters for this function will be displayed as well as a description for each of the parameters.
Examples
C#
Image Processing Examples
- Hello World
- Camera Capture in 7 lines of code
- Shape (Triangle, Rectangle, Circle, Line) Detection
- SURF Feature Detector
- Windows Presentation Foundation (WPF)
- Face detection in Csharp
- Pedestrian Detection, Histogram of oriented gradients (HOG)
- Traffic Sign Detection
- License Plate Recognition (LPR), Optical Character Recognition (OCR)
Computational Geometry Examples
- Delaunay's Triangulation and Voronoi Diagram
- Convex Hull
- Ellipse Fitting
- Minimum Area Rectangle
- Minimum Enclosing Circle
Machine Learning Examples
- Normal Bayes Classifier
- K Nearest Neighbors
- Support Vector Machine (SVM) - thanks to Albert G.
- Expectation-Maximization (EM)
- Neural Network (ANN MLP)
- Mushroom Poisonous Prediction (Decision Tree)