OPENCV形态学操作1
Posted 邓小俊
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形态学操作是指基于形状的一系列图像处理操作,包括膨胀,腐蚀,二值化,开运算,闭运算,顶帽算法,黑帽算法,形态学梯度等,最基本的形态学操作就是膨胀和腐蚀.
一.膨胀
首先需要明确一个概念,膨胀和腐蚀都是针对于图像中较亮的区域而言的,膨胀就是亮的区域变多了,而腐蚀就是暗的区域变多了.
膨胀的功能主要有消除噪声,分割出独立的图像元素,在图像操作的时候,有时候需要对图像中的某些形状进行检测,而这些形状相互连接在一起,不好分开检测,膨胀就能切开这些形状(很小的连接位置),或者图像中有很小块的黑斑,或许是相机上的影响,膨胀,也能消除这些小的黑斑
膨胀的基本思路就是图像与一个核函数进行卷积,并取出结果中的极大值作为结果,使得图像中的高亮区域增长.这个核的形状,锚点都可以进行设置,OPENCV提供了API供我们获得核.
API:Mat getStructuringElement(int 内核形状,Size 内核尺寸,Point 锚点位置)
注:内核形状可以取方形MORPH_RECT,十字形MORPH_CROSS,椭圆形MORPH_ELLIPSE
锚点位置默认值Point(-1,-1),取形状的中心
通过该API就可以获得相应的计算核,接下来计算膨胀的函数为
API:void dilate(源图像,目标图像,膨胀核,锚点,int 迭代次数,int边界模式,int 边界为常数时边界值)
注:该API支持in_place(源图像可以做目的图像参数,算法会修改源图像内数据),迭代次数默认为1
例子如下
Mat srcImage;
//膨胀
const int g_dilateIterMax = 100;//迭代次数
int g_nDilateIterValue;
const int g_dilateCoreMax = 100;//核大小
int g_nDilateCoreValue;
Mat dilateImage;
void OnDilateIterTrackbar(int pos,void* userData);
void onDilateCoreSizeTrackBar(int pos,void* userData);
int main(int argc,char* argv)
{
srcImage = imread("F:\\opencv\\OpenCVImage\\erode_dilate.jpg");
namedWindow("src image");
namedWindow("dilate image");
g_nDilateIterValue = 1;
g_nDilateCoreValue = 5;
createTrackbar("inter count", "dilate image", &g_nDilateIterValue, g_dilateIterMax,OnDilateIterTrackbar);
createTrackbar("core size", "dilate image", &g_nDilateCoreValue, g_dilateCoreMax,onDilateCoreSizeTrackBar);
OnDilateIterTrackbar(g_nDilateIterValue,0);
moveWindow("src image", 0, 0);
moveWindow("dilate image", srcImage.cols, 0);
imshow("src image", srcImage);
waitKey(0);
return 0;
}
//调整迭代次数
void OnDilateIterTrackbar(int pos,void* userData)
{
if(pos == 0||g_nDilateCoreValue == 0)
{
imshow("dilate image", srcImage);
}
else
{
if(g_nDilateCoreValue%2 == 0)
{
g_nDilateCoreValue++;
}
Mat core = getStructuringElement(MORPH_RECT, Size(g_nDilateCoreValue,g_nDilateCoreValue));
dilate(srcImage, dilateImage, core,Point(-1,-1),g_nDilateIterValue);
imshow("dilate image", dilateImage);
}
}
//调整核大小
void onDilateCoreSizeTrackBar(int pos,void* userData)
{
if(pos == 0 || g_nDilateIterValue == 0)
{
imshow("dilate image", srcImage);
}
else
{
if(g_nDilateCoreValue%2 == 0)
{
g_nDilateCoreValue++;
}
Mat core = getStructuringElement(MORPH_RECT, Size(g_nDilateCoreValue,g_nDilateCoreValue));
dilate(srcImage, dilateImage, core,Point(-1,-1),g_nDilateIterValue);
imshow("dilate image", dilateImage);
}
}
二.腐蚀
腐蚀与膨胀正好相反,是求局部最小值的操作,亮的地方会减少,黑的地方会增多,在图像中连接接近的区域,消除高亮造成的噪声
API: void erode(源,目的,核,锚点,迭代次数,边缘类型,边缘为常数时边界值);
注:腐蚀和膨胀API的形式一致
使用代码
//腐蚀
Mat srcImage;
const int g_erodeIterMax = 100;
int g_nErodeIterValue;
const int g_erodeCoreMax = 100;
int g_nErodeCoreValue;
Mat erodeImage;
void OnErodeIterTrackbar(int pos,void* userData);
void onErodeCoreSizeTrackBar(int pos,void* userData);
int main(int argc,char* argv)
{
srcImage = imread("F:\\opencv\\OpenCVImage\\erode_dilate.jpg");
namedWindow("src image");
namedWindow("erode image");
g_nErodeIterValue = 1;
g_nErodeCoreValue = 5;
createTrackbar("inter count", "erode image", &g_nErodeIterValue, g_erodeIterMax,OnErodeIterTrackbar);
createTrackbar("core size", "erode image", &g_nErodeCoreValue, g_erodeCoreMax,onErodeCoreSizeTrackBar);
OnErodeIterTrackbar(g_nErodeIterValue, 0);
moveWindow("src image", 0, 0);
moveWindow("erode image", srcImage.cols, 0);
imshow("src image", srcImage);
waitKey(0);
return 0;
}
//调整迭代次数
void OnErodeIterTrackbar(int pos,void* userData)
{
if(pos == 0 || g_nErodeCoreValue == 0)
{
imshow("erode image", srcImage);
}
else
{
if(g_nErodeCoreValue%2 == 0)
{
g_nErodeCoreValue++;
}
Mat core = getStructuringElement(MORPH_RECT, Size(g_nErodeCoreValue,g_nErodeCoreValue),Point(-1,-1));
erode(srcImage, erodeImage, core,Point(-1,-1),g_nErodeIterValue);
imshow("erode image", erodeImage);
}
}
//调整核大小
void onErodeCoreSizeTrackBar(int pos,void* userData)
{
if(pos == 0 || g_nErodeIterValue == 0)
{
imshow("erode image", srcImage);
}
else
{
if(g_nErodeCoreValue%2 == 0)
{
g_nErodeCoreValue++;
}
Mat core = getStructuringElement(MORPH_RECT, Size(g_nErodeCoreValue,g_nErodeCoreValue),Point(-1,-1));
erode(srcImage, erodeImage, core,Point(-1,-1),g_nErodeIterValue);
imshow("erode image", erodeImage);
}
}
三.形态学滤波算法
形态学的高级操作,往往都建立在基础的膨胀和腐蚀的操作之上
1.开运算:开运算是一个先腐蚀,后膨胀的过程,用于在图像中消除小的物体,在纤细点处分离物体,在平滑化较大的物体的边界的同时不明显改变物体的体积.
2.闭运算:先膨胀后腐蚀的过程,能够用于消除物体中的小型黑洞
3.形态学梯度:膨胀图和腐蚀图之差,对二值图像进行这一操作,可以将团块的边缘突出来,可以使用形态学梯度来保留物体的边缘轮廓.
4.顶帽:源图像和开运算的结果的差值,往往用来分离比邻近点亮一点的斑块,在一幅图具体大幅的背景,而微小物体有比较有规律的情况下,可以使用top_hat运算进行背景的提取
5.黑帽:闭运算的结果与源图像之差,突出了比源图像轮廓周围更暗的区域,往往用于分离比邻近点暗一些的斑块.
核心API:void morpholgyEx(源,目标,int 形态学操作标志,mat 形态学操作内核,Point 锚点,int 迭代次数,int 边界模式,int 边界为常数时的边界值).
注:形态学操作标志的取值如下:MORPH_OPEN开运算 MORPH_CLOSE 闭运算 MORPH_GRENIENT 形态学梯度 MORPH_TOPHAT顶帽 MORPH_BLACKHAT黑帽 MORPH_ERODE腐蚀 MORPH_DILATE 膨胀
形态学操作内核就是前面膨胀腐蚀使用的内核.
使用范例如下:
1.开运算 闭运算 形态学梯度三者联合
//源¡ä图ª?像?
Mat srcImage;
//开a运?算?
const int g_openIterMax = 100;
int g_nopenIterValue;
const int g_openCoreMax = 100;
int g_nopenCoreValue;
Mat openImage;
void OnopenIterTrackbar(int pos,void* userData);
void onopenCoreSizeTrackBar(int pos,void* userData);
//闭À?运?算?
const int g_closeIterMax = 100;
int g_ncloseIterValue;
const int g_closeCoreMax = 100;
int g_ncloseCoreValue;
Mat closeImage;
void OncloseIterTrackbar(int pos,void* userData);
void oncloseCoreSizeTrackBar(int pos,void* userData);
//形?态¬?学¡ì梯¬Y度¨¨
const int g_gredientIterMax = 100;
int g_ngredientIterValue;
const int g_gredientCoreMax = 100;
int g_ngredientCoreValue;
Mat gredientImage;
void OngredientIterTrackbar(int pos,void* userData);
void ongredientCoreSizeTrackBar(int pos,void* userData);
int main(int argc,char* argv[])
{
srcImage = imread("F:\\opencv\\OpenCVImage\\morpholgy.jpg");
g_nopenIterValue = 1;
g_nopenCoreValue = 5;
namedWindow("open image");
createTrackbar("iter count", "open image", &g_nopenIterValue, g_openIterMax,OnopenIterTrackbar,0);
createTrackbar("core size", "open image", &g_nopenCoreValue, g_openCoreMax,onopenCoreSizeTrackBar,0);
onopenCoreSizeTrackBar(g_nopenCoreValue, 0);
g_ncloseCoreValue = 5;
g_ncloseIterValue = 1;
namedWindow("close image");
createTrackbar("iter count", "close image", &g_ncloseIterValue, g_closeIterMax,OncloseIterTrackbar,0);
createTrackbar("core size", "close image", &g_ncloseCoreValue, g_closeCoreMax,oncloseCoreSizeTrackBar,0);
oncloseCoreSizeTrackBar(g_ncloseCoreValue, 0);
g_ngredientCoreValue = 5;
g_ngredientIterValue = 1;
namedWindow("gredient image");
createTrackbar("iter count", "gredient image", &g_ngredientIterValue, g_gredientIterMax,OngredientIterTrackbar,0);
createTrackbar("core size", "gredient image", &g_ngredientCoreValue, g_gredientCoreMax,OngredientIterTrackbar,0);
OngredientIterTrackbar(g_ngredientIterValue, 0);
imshow("src image", srcImage);
moveWindow("src image", 0, 0);
moveWindow("open image", srcImage.cols, 0);
moveWindow("close image", srcImage.cols*2, 0);
moveWindow("gredient image", srcImage.cols*3, 0);
waitKey(0);
return 0;
}
void OnopenIterTrackbar(int pos,void* userData)
{
if(g_nopenCoreValue == 0||g_nopenIterValue == 0)
{
imshow("open image", srcImage);
}
else
{
if(g_nopenCoreValue%2 == 0)
g_nopenCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_nopenCoreValue,g_nopenCoreValue));
morphologyEx(srcImage, openImage, MORPH_OPEN, core,Point(-1,-1),g_nopenIterValue);
imshow("open image", openImage);
}
}
void onopenCoreSizeTrackBar(int pos,void* userData)
{
if(g_nopenCoreValue == 0||g_nopenIterValue == 0)
{
imshow("open image", srcImage);
}
else
{
if(g_nopenCoreValue%2 == 0)
g_nopenCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_nopenCoreValue,g_nopenCoreValue));
morphologyEx(srcImage, openImage, MORPH_OPEN, core,Point(-1,-1),g_nopenIterValue);
imshow("open image", openImage);
}
}
void OncloseIterTrackbar(int pos,void* userData)
{
if(g_ncloseCoreValue == 0||g_ncloseIterValue == 0)
{
imshow("close image", srcImage);
}
else
{
if(g_ncloseCoreValue%2 == 0)
g_ncloseCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_ncloseCoreValue,g_ncloseCoreValue));
morphologyEx(srcImage, closeImage, MORPH_CLOSE, core,Point(-1,-1),g_ncloseIterValue);
imshow("close image", closeImage);
}
}
void oncloseCoreSizeTrackBar(int pos,void* userData)
{
if(g_ncloseCoreValue == 0||g_ncloseIterValue == 0)
{
imshow("close image", srcImage);
}
else
{
if(g_ncloseCoreValue%2 == 0)
g_ncloseCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_ncloseCoreValue,g_ncloseCoreValue));
morphologyEx(srcImage, closeImage, MORPH_CLOSE, core,Point(-1,-1),g_ncloseIterValue);
imshow("close image", closeImage);
}
}
void OngredientIterTrackbar(int pos,void* userData)
{
if(g_ngredientCoreValue == 0||g_ngredientIterValue == 0)
{
imshow("gredient image", srcImage);
}
else
{
if(g_ngredientCoreValue%2 == 0)
g_ngredientCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_ngredientCoreValue,g_ngredientCoreValue));
morphologyEx(srcImage, gredientImage, MORPH_GRADIENT, core,Point(-1,-1),g_ngredientIterValue);
imshow("gredient image", gredientImage);
}
}
void ongredientCoreSizeTrackBar(int pos,void* userData)
{
if(g_ngredientCoreValue == 0||g_ngredientIterValue == 0)
{
imshow("gredient image", srcImage);
}
else
{
if(g_ngredientCoreValue%2 == 0)
g_ngredientCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_ngredientCoreValue,g_ngredientCoreValue));
morphologyEx(srcImage, gredientImage, MORPH_GRADIENT, core,Point(-1,-1),g_ngredientIterValue);
imshow("gredient image", gredientImage);
}
}
2. 顶帽 黑帽结合
Mat srcImage;
//顶£¤帽¡À tophat
const int g_tophatIterMax = 100;
int g_ntophatIterValue;
const int g_tophatCoreMax = 100;
int g_ntophatCoreValue;
Mat tophatImage;
void OntophatIterTrackbar(int pos,void* userData);
void ontophatCoreSizeTrackBar(int pos,void* userData);
//黑¨²帽¡À
const int g_blackhatIterMax = 100;
int g_nblackhatIterValue;
const int g_blackhatCoreMax = 100;
int g_nblackhatCoreValue;
Mat blackhatImage;
void OnblackhatIterTrackbar(int pos,void* userData);
void onblackhatCoreSizeTrackBar(int pos,void* userData);
int main(int argc,char* argv[])
{
srcImage = imread("F:\\opencv\\OpenCVImage\\morpholgy.jpg");
g_ntophatIterValue = 1;
g_ntophatCoreValue = 5;
namedWindow("tophat image");
createTrackbar("iter count", "tophat image", &g_ntophatIterValue, g_tophatIterMax,OntophatIterTrackbar,0);
createTrackbar("core size", "tophat image", &g_ntophatCoreValue, g_tophatCoreMax,ontophatCoreSizeTrackBar,0);
ontophatCoreSizeTrackBar(g_ntophatCoreValue, 0);
g_nblackhatCoreValue = 5;
g_nblackhatIterValue = 1;
namedWindow("blackhat image");
createTrackbar("iter count", "blackhat image", &g_nblackhatIterValue, g_blackhatIterMax,OnblackhatIterTrackbar,0);
createTrackbar("core size", "blackhat image", &g_nblackhatCoreValue, g_blackhatCoreMax,onblackhatCoreSizeTrackBar,0);
onblackhatCoreSizeTrackBar(g_nblackhatCoreValue, 0);
imshow("src image", srcImage);
moveWindow("src image", 0, 0);
moveWindow("tophat image", srcImage.cols, 0);
moveWindow("blackhat image", srcImage.cols*2, 0);
waitKey(0);
return 0;
}
void OntophatIterTrackbar(int pos,void* userData)
{
if(g_ntophatCoreValue == 0||g_ntophatIterValue == 0)
{
imshow("tophat image", srcImage);
}
else
{
if(g_ntophatCoreValue%2 == 0)
g_ntophatCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_ntophatCoreValue,g_ntophatCoreValue));
morphologyEx(srcImage, tophatImage, MORPH_TOPHAT, core,Point(-1,-1),g_ntophatIterValue);
imshow("tophat image", tophatImage);
}
}
void ontophatCoreSizeTrackBar(int pos,void* userData)
{
if(g_ntophatCoreValue == 0||g_ntophatIterValue == 0)
{
imshow("tophat image", srcImage);
}
else
{
if(g_ntophatCoreValue%2 == 0)
g_ntophatCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_ntophatCoreValue,g_ntophatCoreValue));
morphologyEx(srcImage, tophatImage, MORPH_TOPHAT, core,Point(-1,-1),g_ntophatIterValue);
imshow("tophat image", tophatImage);
}
}
void OnblackhatIterTrackbar(int pos,void* userData)
{
if(g_nblackhatCoreValue == 0||g_nblackhatIterValue == 0)
{
imshow("blackhat image", srcImage);
}
else
{
if(g_nblackhatCoreValue%2 == 0)
g_nblackhatCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_nblackhatCoreValue,g_nblackhatCoreValue));
morphologyEx(srcImage, blackhatImage, MORPH_BLACKHAT, core,Point(-1,-1),g_nblackhatIterValue);
imshow("blackhat image", blackhatImage);
}
}
void onblackhatCoreSizeTrackBar(int pos,void* userData)
{
if(g_nblackhatCoreValue == 0||g_nblackhatIterValue == 0)
{
imshow("blackhat image", srcImage);
}
else
{
if(g_nblackhatCoreValue%2 == 0)
g_nblackhatCoreValue++;
Mat core = getStructuringElement(MORPH_RECT, Size(g_nblackhatCoreValue,g_nblackhatCoreValue));
morphologyEx(srcImage, blackhatImage, MORPH_BLACKHAT, core,Point(-1,-1),g_nblackhatIterValue);
imshow("blackhat image", blackhatImage);
}
}
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