Class cv::Moments#

struct returned by cv::moments View details

#include <opencv2/core/types.hpp>

Collaboration diagram for cv::Moments:

Detailed Description#

struct returned by cv::moments

The spatial moments \(\texttt{Moments::m}_{ji}\) are computed as:

\[\texttt{m} _{ji}= \sum _{x,y} \left ( \texttt{array} (x,y) \cdot x^j \cdot y^i \right )\]

The central moments \(\texttt{Moments::mu}_{ji}\) are computed as:

\[\texttt{mu} _{ji}= \sum _{x,y} \left ( \texttt{array} (x,y) \cdot (x - \bar{x} )^j \cdot (y - \bar{y} )^i \right )\]

where \((\bar{x}, \bar{y})\) is the mass center:

\[\bar{x} = \frac{\texttt{m}_{10}}{\texttt{m}_{00}} , \; \bar{y} = \frac{\texttt{m}_{01}}{\texttt{m}_{00}}\]

The normalized central moments \(\texttt{Moments::nu}_{ij}\) are computed as:

\[\texttt{nu} _{ji}= \frac{\texttt{mu}_{ji}}{\texttt{m}_{00}^{(i+j)/2+1}} .\]

The moments of a contour are defined in the same way but computed using the Green’s formula (see http://en.wikipedia.org/wiki/Green_theorem). So, due to a limited raster resolution, the moments computed for a contour are slightly different from the moments computed for the same rasterized contour.

Note

\(\texttt{mu}_{00}=\texttt{m}_{00}\), \(\texttt{nu}_{00}=1\) \(\texttt{nu}_{10}=\texttt{mu}_{10}=\texttt{mu}_{01}=\texttt{mu}_{10}=0\) , hence the values are not stored.

Note

Since the contour moments are computed using Green formula, you may get seemingly odd results for contours with self-intersections, e.g. a zero area (m00) for butterfly-shaped contours.

Constructor & Destructor Documentation#

Moments()#

cv::Moments::Moments()

the default constructor

Moments()#

cv::Moments::Moments(
double m00,
double m10,
double m01,
double m20,
double m11,
double m02,
double m30,
double m21,
double m12,
double m03 )

the full constructor

Member Data Documentation#

nu20#

double cv::Moments::nu20

nu11#

double cv::Moments::nu11

nu02#

double cv::Moments::nu02

nu30#

double cv::Moments::nu30

nu21#

double cv::Moments::nu21

nu12#

double cv::Moments::nu12

nu03#

double cv::Moments::nu03

Source file#

The documentation for this class was generated from the following file:

opencv2/core/types.hpp