Question

我试图在opencv和c ++中实现以下链接http://in.mathworks.com/help/vision/examples/motion-based-multiple-object-tracking.html。我创建了一个说ex：

的课程

class assign
{
    vector <int> id;
    vector <int> area;
    vector<Point> centroid;
};

在此之后我创建了一个对象

assign id;

现在我想分配质心值和其他值。我试过的是

id.centroid (p);

其中p是“点”但是我得到了错误。我不知道我哪里出错了。

Answer 1

centroid是班级private的{{1}}成员。如果您想直接访问它，您应该公开

assign

如果您想在class assign { public: vector<Point> centroid; //... };中添加Point，则应该

centroid

Answer 2

主要答案已由songyuanyao给出。我想要添加的是一个可能的解决方案，它允许您使用已经尝试过的成员变量。

如果您想使用centroid获取并设置成员id.centroid(p)，您可以使用以下类声明：

class Assign
{
public:
    vector<Point> centroid();
    void          centroid(vector<Point> c);
private:
    vector<Point> m_centroid;
};

该定义可能如下所示：

// getter
vector<Point> Assign::centroid() {
    return m_centroid;
}

// setter
void Assign::centroid(vector<Point> c) {
    m_centroid = c;
}

现在，如果使用id.centroid(p)设置成员，将调用重载的setter并设置变量。如果您调用p = id.centroid()（空参数列表），将调用重载的getter并返回当前的m_centroid。

Answer 3

添加到之前的答案;如果你想扩展你的课程，可以在构建你的对象时为你完成。

class Assign {
private:
    std::vector<int> m_vIds;
    std::vector<int> m_vAreas;
    std::vector<Vec2> m_vCentroids;

public:
    Assign();  // Default Constructor Same As What You Have But Not Declared.
    Assign( int* pIds, int* pAreas, int* pCentroids ); // Create By Using Pointers
    // Create By Passing In Either Pre Filled Vectors Or Even An Empty 
    // Vectors To Be Filled Out Later. Passes By Reference. This Will
    // Also Set The Variables That Are Passed In From The Caller.
    Assign( std::vector<int>& vIds, std::vector<int>& vAreas, std::vector<Vec2>& vCentroids );

    // Since You Are Using Vectors Within This Class It Is Also Good To
    // Have A Destructor To Clear These Out Once The Object Is Done And
    // Ready To Be Destroyed Or Removed From Memory
    ~Assign();
};

// The Destructor Would Look Like This
Assign::~Asign() {
    if ( !m_vIds.empty() ) {
        m_vIds.clear();
    }
    if ( !m_vAreas.empty() ) {
        m_vAreas.clear();
    }
    if ( !m_vCentroids.empty() ) {
        m_vCentroids.empty();
    }
} // ~Assign

// NOTE: I used Vec2 instead of point due to my use of programming
// 2D & 3D Graphics Rendering Engines; Most Graphics APIs and Libraries
// along with Most Math Libraries Will Not Have A Point Class; Most Will
// Use Vec2 or Vec3 - Vector2  or Vector3 & Vector4 Since in terms of
// memory they are exactly the same thing. It is up to you to know which
// objects are points or locations, and which are vectors as in forces,
// velocities, accelerations, directions, normals etc. The only major
// difference between a discrete Point Class or Structure versus a Vector
// Class is that the Vector Class usually has operations defined with it
// to do vector mathematics such as addition, subtraction, multiplication by
// value, multiplication by vector, division by value, division by vector,
// cross & dot product, comparisons, testing if vector is 0, setting it to
// be a normal vector, returning the magnitude or length and a few others.
// The general point class or object is usually just data values or
// simply coordinates without operations.

为班级成员

3 个答案: