via OpenCv 提取分离前景和背景
1 #include <opencv2/highgui/highgui.hpp> 2 #include <opencv2/core/core.hpp> 3 #include <vector> 4 #include <iostream> 5 #include <opencv2/imgproc/imgproc.hpp> 6 //#include "../../../../../Downloads/colourhistogram.h" 7 using namespace std; 8 using namespace cv; 9 static void help() 10 { 11 cout << "\nThis program demonstrates GrabCut segmentation -- select an object in a region\n" 12 "and then grabcut will attempt to segment it out.\n" 13 "Call:\n" 14 "./grabcut <image_name>\n" 15 "\nSelect a rectangular area around the object you want to segment\n" << 16 "\nHot keys: \n" 17 "\tESC - quit the program\n" 18 "\tr - restore the original image\n" 19 "\tn - next iteration\n" 20 "\n" 21 "\tleft mouse button - set rectangle\n" 22 "\n" 23 "\tCTRL+left mouse button - set GC_BGD pixels\n" 24 "\tSHIFT+left mouse button - set CG_FGD pixels\n" 25 "\n" 26 "\tCTRL+right mouse button - set GC_PR_BGD pixels\n" 27 "\tSHIFT+right mouse button - set CG_PR_FGD pixels\n" << endl; 28 } 29 30 const Scalar RED = Scalar(0,0,255); 31 const Scalar PINK = Scalar(230,130,255); 32 const Scalar BLUE = Scalar(255,0,0); 33 const Scalar LIGHTBLUE = Scalar(255,255,160); 34 const Scalar GREEN = Scalar(0,255,0); 35 36 const int BGD_KEY = CV_EVENT_FLAG_CTRLKEY; //Ctrl键 37 const int FGD_KEY = CV_EVENT_FLAG_SHIFTKEY; //Shift键 38 39 static void getBinMask( const Mat& comMask, Mat& binMask ) 40 { 41 if( comMask.empty() || comMask.type()!=CV_8UC1 ) 42 CV_Error( CV_StsBadArg, "comMask is empty or has incorrect type (not CV_8UC1)" ); 43 if( binMask.empty() || binMask.rows!=comMask.rows || binMask.cols!=comMask.cols ) 44 binMask.create( comMask.size(), CV_8UC1 ); 45 binMask = comMask & 1; //得到mask的最低位,实际上是只保留确定的或者有可能的前景点当做mask 46 } 47 48 class GCApplication 49 { 50 public: 51 enum{ NOT_SET = 0, IN_PROCESS = 1, SET = 2 }; 52 static const int radius = 2; 53 static const int thickness = -1; 54 55 void reset(); 56 void setImageAndWinName( const Mat& _image, const string& _winName ); 57 void showImage() const; 58 void mouseClick( int event, int x, int y, int flags, void* param ); 59 int nextIter(); 60 int getIterCount() const { return iterCount; } 61 private: 62 void setRectInMask(); 63 void setLblsInMask( int flags, Point p, bool isPr ); 64 65 const string* winName; 66 const Mat* image; 67 Mat mask; 68 Mat bgdModel, fgdModel; 69 70 uchar rectState, lblsState, prLblsState; 71 bool isInitialized; 72 73 Rect rect; 74 vector<Point> fgdPxls, bgdPxls, prFgdPxls, prBgdPxls; 75 int iterCount; 76 }; 77 78 /*给类的变量赋值*/ 79 void GCApplication::reset() 80 { 81 if( !mask.empty() ) 82 mask.setTo(Scalar::all(GC_BGD)); 83 bgdPxls.clear(); fgdPxls.clear(); 84 prBgdPxls.clear(); prFgdPxls.clear(); 85 86 isInitialized = false; 87 rectState = NOT_SET; //NOT_SET == 0 88 lblsState = NOT_SET; 89 prLblsState = NOT_SET; 90 iterCount = 0; 91 } 92 93 /*给类的成员变量赋值而已*/ 94 void GCApplication::setImageAndWinName( const Mat& _image, const string& _winName ) 95 { 96 if( _image.empty() || _winName.empty() ) 97 return; 98 image = &_image; 99 winName = &_winName; 100 mask.create( image->size(), CV_8UC1); 101 reset(); 102 } 103 104 /*显示4个点，一个矩形和图像内容，因为后面的步骤很多地方都要用到这个函数，所以单独拿出来*/ 105 void GCApplication::showImage() const 106 { 107 if( image->empty() || winName->empty() ) 108 return; 109 110 Mat res; 111 Mat binMask; 112 if( !isInitialized ) 113 image->copyTo( res ); 114 else 115 { 116 getBinMask( mask, binMask ); 117 image->copyTo( res, binMask ); //按照最低位是0还是1来复制，只保留跟前景有关的图像，比如说可能的前景，可能的背景 118 } 119 120 vector<Point>::const_iterator it; 121 /*下面4句代码是将选中的4个点用不同的颜色显示出来*/ 122 for( it = bgdPxls.begin(); it != bgdPxls.end(); ++it ) //迭代器可以看成是一个指针 123 circle( res, *it, radius, BLUE, thickness ); 124 for( it = fgdPxls.begin(); it != fgdPxls.end(); ++it ) //确定的前景用红色表示 125 circle( res, *it, radius, RED, thickness ); 126 for( it = prBgdPxls.begin(); it != prBgdPxls.end(); ++it ) 127 circle( res, *it, radius, LIGHTBLUE, thickness ); 128 for( it = prFgdPxls.begin(); it != prFgdPxls.end(); ++it ) 129 circle( res, *it, radius, PINK, thickness ); 130 131 /*画矩形*/ 132 if( rectState == IN_PROCESS || rectState == SET ) 133 rectangle( res, Point( rect.x, rect.y ), Point(rect.x + rect.width, rect.y + rect.height ), GREEN, 2); 134 135 imshow( *winName, res ); 136 } 137 138 /*该步骤完成后，mask图像中rect内部是3，外面全是0*/ 139 void GCApplication::setRectInMask() 140 { 141 assert( !mask.empty() ); 142 mask.setTo( GC_BGD ); //GC_BGD == 0 143 rect.x = max(0, rect.x); 144 rect.y = max(0, rect.y); 145 rect.width = min(rect.width, image->cols-rect.x); 146 rect.height = min(rect.height, image->rows-rect.y); 147 (mask(rect)).setTo( Scalar(GC_PR_FGD) ); //GC_PR_FGD == 3，矩形内部,为可能的前景点 148 } 149 150 void GCApplication::setLblsInMask( int flags, Point p, bool isPr ) 151 { 152 vector<Point> *bpxls, *fpxls; 153 uchar bvalue, fvalue; 154 if( !isPr ) //确定的点 155 { 156 bpxls = &bgdPxls; 157 fpxls = &fgdPxls; 158 bvalue = GC_BGD; //0 159 fvalue = GC_FGD; //1 160 } 161 else //概率点 162 { 163 bpxls = &prBgdPxls; 164 fpxls = &prFgdPxls; 165 bvalue = GC_PR_BGD; //2 166 fvalue = GC_PR_FGD; //3 167 } 168 if( flags & BGD_KEY ) 169 { 170 bpxls->push_back(p); 171 circle( mask, p, radius, bvalue, thickness ); //该点处为2 172 } 173 if( flags & FGD_KEY ) 174 { 175 fpxls->push_back(p); 176 circle( mask, p, radius, fvalue, thickness ); //该点处为3 177 } 178 } 179 180 /*鼠标响应函数，参数flags为CV_EVENT_FLAG的组合*/ 181 void GCApplication::mouseClick( int event, int x, int y, int flags, void* ) 182 { 183 // TODO add bad args check 184 switch( event ) 185 { 186 case CV_EVENT_LBUTTONDOWN: // set rect or GC_BGD(GC_FGD) labels 187 { 188 bool isb = (flags & BGD_KEY) != 0, 189 isf = (flags & FGD_KEY) != 0; 190 if( rectState == NOT_SET && !isb && !isf )//只有左键按下时 191 { 192 rectState = IN_PROCESS; //表示正在画矩形 193 rect = Rect( x, y, 1, 1 ); 194 } 195 if ( (isb || isf) && rectState == SET ) //按下了alt键或者shift键，且画好了矩形，表示正在画前景背景点 196 lblsState = IN_PROCESS; 197 } 198 break; 199 case CV_EVENT_RBUTTONDOWN: // set GC_PR_BGD(GC_PR_FGD) labels 200 { 201 bool isb = (flags & BGD_KEY) != 0, 202 isf = (flags & FGD_KEY) != 0; 203 if ( (isb || isf) && rectState == SET ) //正在画可能的前景背景点 204 prLblsState = IN_PROCESS; 205 } 206 break; 207 case CV_EVENT_LBUTTONUP: 208 if( rectState == IN_PROCESS ) 209 { 210 rect = Rect( Point(rect.x, rect.y), Point(x,y) ); //矩形结束 211 rectState = SET; 212 setRectInMask(); 213 assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() ); 214 showImage(); 215 } 216 if( lblsState == IN_PROCESS ) //已画了前后景点 217 { 218 setLblsInMask(flags, Point(x,y), false); //画出前景点 219 lblsState = SET; 220 showImage(); 221 } 222 break; 223 case CV_EVENT_RBUTTONUP: 224 if( prLblsState == IN_PROCESS ) 225 { 226 setLblsInMask(flags, Point(x,y), true); //画出背景点 227 prLblsState = SET; 228 showImage(); 229 } 230 break; 231 case CV_EVENT_MOUSEMOVE: 232 if( rectState == IN_PROCESS ) 233 { 234 rect = Rect( Point(rect.x, rect.y), Point(x,y) ); 235 assert( bgdPxls.empty() && fgdPxls.empty() && prBgdPxls.empty() && prFgdPxls.empty() ); 236 showImage(); //不断的显示图片 237 } 238 else if( lblsState == IN_PROCESS ) 239 { 240 setLblsInMask(flags, Point(x,y), false); 241 showImage(); 242 } 243 else if( prLblsState == IN_PROCESS ) 244 { 245 setLblsInMask(flags, Point(x,y), true); 246 showImage(); 247 } 248 break; 249 } 250 } 251 252 /*该函数进行grabcut算法，并且返回算法运行迭代的次数*/ 253 int GCApplication::nextIter() 254 { 255 if( isInitialized ) 256 //使用grab算法进行一次迭代，参数2为mask，里面存的mask位是：矩形内部除掉那些可能是背景或者已经确定是背景后的所有的点，且mask同时也为输出 257 //保存的是分割后的前景图像 258 grabCut( *image, mask, rect, bgdModel, fgdModel, 1 ); 259 else 260 { 261 if( rectState != SET ) 262 return iterCount; 263 264 if( lblsState == SET || prLblsState == SET ) 265 grabCut( *image, mask, rect, bgdModel, fgdModel, 1, GC_INIT_WITH_MASK ); 266 else 267 grabCut( *image, mask, rect, bgdModel, fgdModel, 1, GC_INIT_WITH_RECT ); 268 269 isInitialized = true; 270 } 271 iterCount++; 272 273 bgdPxls.clear(); fgdPxls.clear(); 274 prBgdPxls.clear(); prFgdPxls.clear(); 275 276 return iterCount; 277 } 278 279 GCApplication gcapp; 280 281 static void on_mouse( int event, int x, int y, int flags, void* param ) 282 { 283 gcapp.mouseClick( event, x, y, flags, param ); 284 } 285 286 int main( int argc, char** argv ) 287 { 288 289 string filename = "D:\\images\\dog.jpg"; 290 Mat image = imread( "Lena.jpg", 1 ); 291 if( image.empty() ) 292 { 293 cout << "\n Durn, couldn't read image filename " << filename << endl; 294 return 1; 295 } 296 297 help(); 298 299 const string winName = "image"; 300 cvNamedWindow( winName.c_str(), CV_WINDOW_AUTOSIZE ); 301 cvSetMouseCallback( winName.c_str(), on_mouse, 0 ); 302 303 gcapp.setImageAndWinName( image, winName ); 304 gcapp.showImage(); 305 306 for(;;) 307 { 308 int c = cvWaitKey(0); 309 switch( (char) c ) 310 { 311 case '\x1b': 312 cout << "Exiting ..." << endl; 313 goto exit_main; 314 case 'r': 315 cout << endl; 316 gcapp.reset(); 317 gcapp.showImage(); 318 break; 319 case 'n': 320 int iterCount = gcapp.getIterCount(); 321 cout << "<" << iterCount << "... "; 322 int newIterCount = gcapp.nextIter(); 323 if( newIterCount > iterCount ) 324 { 325 gcapp.showImage(); 326 cout << iterCount << ">" << endl; 327 } 328 else 329 cout << "rect must be determined>" << endl; 330 break; 331 } 332 } 333 334 exit_main: 335 336 cvDestroyWindow( winName.c_str() ); 337 return 0; 338 }
设置snake算法使用的参数:
alpha代表点相互靠拢的权值(0-1.0)
beta表示弯曲能量（越小越容易弯曲）(0-1.0)，
gamma表示整体能量(0-1.0)
