形態學操作是指基於形狀的一系列圖像處理操作,包括膨脹,腐蝕,二值化,開運算,閉運算,頂帽算法,黑帽算法,形態學梯度等,最基本的形態學操作就是膨脹和腐蝕.
一.膨脹
首先需要明確一個概念,膨脹和腐蝕都是針對於圖像中較亮的區域而言的,膨脹就是亮的區域變多了,而腐蝕就是暗的區域變多了.
膨脹的功能主要有消除噪聲,分割出獨立的圖像元素,在圖像操作的時候,有時候需要對圖像中的某些形狀進行檢測,而這些形狀相互連接在一起,不好分開檢測,膨脹就能切開這些形狀(很小的連接位置),或者圖像中有很小塊的黑斑,或許是相機上的影響,膨脹,也能消除這些小的黑斑
膨脹的基本思路就是圖像與一個核函數進行卷積,並取出結果中的極大值作為結果,使得圖像中的高亮區域增長.這個核的形狀,錨點都可以進行設置,OPENCV提供了API供我們獲得核.
API:Mat getStructuringElement(int 內核形狀,Size 內核尺寸,Point 錨點位置)
注:內核形狀可以取方形MORPH_RECT,十字形MORPH_CROSS,橢圓形MORPH_ELLIPSE
錨點位置默認值Point(-1,-1),取形狀的中心
通過該API就可以獲得相應的計算核,接下來計算膨脹的函數為
API:void dilate(源圖像,目標圖像,膨脹核,錨點,int 迭代次數,int邊界模式,int 邊界為常數時邊界值)
注:該API支持in_place(源圖像可以做目的圖像參數,算法會修改源圖像內數據),迭代次數默認為1
例子如下
Mat srcImage;
//膨脹
const int g_dilateIterMax = 100;//迭代次數
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;
}
//調整迭代次數
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);
}
}
//調整核大小
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.腐蝕
腐蝕與膨脹正好相反,是求局部最小值的操作,亮的地方會減少,黑的地方會增多,在圖像中連接接近的區域,消除高亮造成的噪聲
API: void erode(源,目的,核,錨點,迭代次數,邊緣類型,邊緣為常數時邊界值);
注:腐蝕和膨脹API的形式一致
使用代碼
//腐蝕
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;
}
//調整迭代次數
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);
}
}
//調整核大小
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.形態學濾波算法
形態學的高級操作,往往都建立在基礎的膨脹和腐蝕的操作之上
1.開運算:開運算是一個先腐蝕,后膨脹的過程,用於在圖像中消除小的物體,在纖細點處分離物體,在平滑化較大的物體的邊界的同時不明顯改變物體的體積.
2.閉運算:先膨脹后腐蝕的過程,能夠用於消除物體中的小型黑洞
3.形態學梯度:膨脹圖和腐蝕圖之差,對二值圖像進行這一操作,可以將團塊的邊緣突出來,可以使用形態學梯度來保留物體的邊緣輪廓.
4.頂帽:源圖像和開運算的結果的差值,往往用來分離比鄰近點亮一點的斑塊,在一幅圖具體大幅的背景,而微小物體有比較有規律的情況下,可以使用top_hat運算進行背景的提取
5.黑帽:閉運算的結果與源圖像之差,突出了比源圖像輪廓周圍更暗的區域,往往用於分離比鄰近點暗一些的斑塊.
核心API:void morpholgyEx(源,目標,int 形態學操作標志,mat 形態學操作內核,Point 錨點,int 迭代次數,int 邊界模式,int 邊界為常數時的邊界值).
注:形態學操作標志的取值如下:MORPH_OPEN開運算 MORPH_CLOSE 閉運算 MORPH_GRENIENT 形態學梯度 MORPH_TOPHAT頂帽 MORPH_BLACKHAT黑帽 MORPH_ERODE腐蝕 MORPH_DILATE 膨脹
形態學操作內核就是前面膨脹腐蝕使用的內核.
使用范例如下:
1.開運算 閉運算 形態學梯度三者聯合
//源¡ä圖ª?像?
Mat srcImage;
//開a運?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);
//閉À?運?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?態¬?學¡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. 頂帽 黑帽結合
Mat srcImage;
//頂£¤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);
}
}