OpenCV Source Learning: getstructuringelement function;

The Getstructuringelement function is attributed to morphology, and the structure of the specified size and shape can be established.

Prototype:

/** @brief Returns A structuring element of the specified size and shape for morphological operations. The function constructs and returns the structuring element that can is further passed to CV::ERODE,CV::d ilate or Cv::morp Hologyex. But you can also construct a arbitrary binary mask yourself and use it asthe structuring element. @param shape Element sha PE that could is one of Cv::morphshapes@param ksize Size of the structuring element. @param anchor anchor position within T He element. The default value \f$ ( -1,-1) \f$ means that theanchor are at the center. Note that only the shape of a cross-shaped element depends on the anchorposition. In and cases the anchor just regulates how much the result of the morphologicaloperation is shifted. */cv_exports_w Mat getstructuringelement (intShape, Size ksize, point anchor = Point (-1,-1));

Source Code Analysis:

Cv::mat Cv::getstructuringelement (intshape, Size ksize, point anchor) {    intI, J; intR =0, C =0; DoubleINV_R2 =0; Cv_assert (Shape= = Morph_rect | | Shape = = Morph_cross | | Shape = =morph_ellipse); Currently supports three shapes of cell creation: rectangular, cross-shaped, oval; Anchor=Normalizeanchor (anchor, ksize);    When the default is -1,-1, calculate anchor; if(Ksize = = Size (1,1))//When a given size of 1, 1 o'clock, indicates a point, which can be represented by a rectangle; shape=Morph_rect; if(Shape = =morph_ellipse)//ellipse; {R= ksize.height/2; C= ksize.width/2; INV_R2= r?1./((Double) r*r):0;    } Mat Elem (Ksize, cv_8u);  for(i =0; i < ksize.height; i++)//For each row, calculate the range of 0,1; {Uchar* ptr =elem.ptr (i); intJ1 =0, J2 =0; if(Shape = = Morph_rect | | (Shape = = Morph_cross && i = =anchor.y))//Rectangle, or cross y anchor point when J2 is ksize.width; J2=Ksize.width; Else if(Shape = =morph_cross) J1= anchor.x, J2 = J1 +1; else//ellipse;        {            intDY = i-R; if(Std::abs (DY) <=r) {intDX = saturate_cast<int> (C*STD::SQRT (r*r-dy*dy) *inv_r2)); Calculate the offset of x; J1= Std::max (C-DX,0 ); J2= Std::min (c + dx +1, Ksize.width); }        }         for(j =0; J < J1; J + +)//From these three for can be seen, (0,j1) between 0, (J1, J2) between 1, (J2, ksize.width) between 0; PTR[J]=0;  for(; J < J2; J + +) Ptr[j]=1;  for(; J < Ksize.width; J + +) Ptr[j]=0; }    returnElem;}

OpenCV Source Learning: getstructuringelement function;