learning OpenCV3 - data type

三類

• basic data types

  • 一般是已經從c++中繼承的
  • int, float, etc
  • vectors,matrices,simple geometric concepts like points, rectangles,sizes

• helper objects

  • 表明一些更抽象的概念
  • garbage-collecting pointer class
  • range objects used for slicing
  • abstractions such as termination criteria

• large array types

  • contain arrays or other assemblies of primitives or, more often, the basic data types

• cv::Mat class

  • 表示任意維數組
  • 包含其餘對象,如 稀疏矩陣 cv::SparseMat class

• 模板類 cv::Vec<>

  • 表明 fixed vector classes
  • 用於一些編譯時就已知維度的小向量

• fixed matrix classes

  • associated with the template cv::Matx<>.
  • certain specific small matrix operations
  • the dimensionality of the fixed matrix classes must be known at compile time

• point classes

  • their members are accessed by named variables (mypoint.x, mypoint.y, etc.) rather than by a vector index (myvec[0],myvec[1], etc.)

• cv::Scalar

  • four-dimensional point
  • generate an arbitrary four-component vector

• cv::Size and cv::Rect

  • cv::Size -- having data members width and height rather than x and y
  • cv::Rect -- all four
  • cv::RotatedRect not axis-aligned 非抽對稱

point classes

• 能夠是任意類型的

• 有兩個模板

  • 2-D
  • 3-D
  • cv::Point2i or cv::Point3f (第一個數-維度, 第二個數-精度)
  • b is an unsigned character, s is a short integer, i is a 32-bit integer, f is a 32-bit floating-point number, and d is a 64- bit floating-point number

<font color=red size =22>Example</font>

Operation	Example
Default constructors	cv::Point2i p; cv::Point3f p;
Copy constructor	cv::Point3f p2( p1 );
Value constructors	cv::Point2i p( x0, x1 ); cv::Point3d p( x0, x1, x2 );
Cast to the fixed vector classes	(cv::Vec3f) p;
Member access	p.x; p.y; // and for three-dimensional // point classes: p.z
Dot product	float x = p1.dot( p2 )
Double-precision dot product	double x = p1.ddot( p2 )
Cross product	p1.cross( p2 ) // (for three-dimensional point // classes only)
Query if point p is inside rectangle r	p.inside( r ) // (for two-dimensional point // classes only)

cv::Scalar class

size classes

cv::Rect class

cv::RotatedRect class

fixed matrix classes

fixed vector classes

complex number classes

associated with the STL complex number class template complex<>

Helper Objects

cv::TermCriteria class

Many algorithms require a stopping condition to know when to quit

• COUNT or MAX_ITER

  • 中止條件一般是有限的迭代數或出現錯誤參數

cv::TermCriteria
封裝一個或兩個中止條件，直接傳遞給OpenCV算法
有三個成員變量type, maxCount, epsilon