《学习OpenCV》练习题第四章第八题ab

这道题是利用OpenCV例子程序里自带的人脸检测程序，做点图像的复制操作以及alpha融合。

说明：人脸检测的程序我参照了网上现有的例子程序，没有用我用的OpenCV版本（2.4.5）的facedetect.c，人脸检测部分是一个月前写的程序，这次做了点改动，以前的部分注释了起来。

代码：

     

  1 #include <opencv/cv.h> 
  2 #include <opencv/highgui.h>
  3 #include <opencv_libs.h>
  4 
  5 #include <stdio.h> 
  6 #include <stdlib.h> 
  7 #include <string.h> 
  8 #include <assert.h> 
  9 #include <math.h> 
 10 #include <float.h> 
 11 #include <limits.h> 
 12 #include <time.h> 
 13 #include <ctype.h>
 14 
 15 /*
 16  *《学习OpenCV》第四章第八题  
 17  * 完成时间：3:43 10/5 星期六 2013  
 18  * 作者：[email protected]
 19  */    
 20 
 21 
 22 /* Result window title */
 23 #define  WND_RESULT   "result"
 24 
 25 static CvMemStorage* storage = 0; 
 26 static CvHaarClassifierCascade* cascade = 0;
 27 
 28 void detect_and_draw( IplImage* image );
 29 
 30 const char* cascade_name = 
 31     "haarcascade_frontalface_alt.xml"; 
 32 
 33 /* Skull image */
 34 IplImage* g_skullImage;
 35 
 36 /* Trackbar initial value */
 37 int g_trackbar_value = 5;
 38 /* Tackbar total values */
 39 int g_trackbar_total = 10;
 40 
 41 /* Alpha blend's alpha */
 42 double g_alpha = 0;
 43 
 44 /* Trackbar callback function */
 45 void switch_callback(int pos)
 46 {
 47     printf("Trackbar event.  pos: %d\n", pos);
 48     g_alpha = (double)pos / g_trackbar_total;
 49 }
 50 
 51 int main( ) 
 52 { 
 53     CvCapture* capture = cvCreateCameraCapture(0);
 54     if(!capture)
 55     {
 56         printf("Camera error.\n");
 57         return -1;
 58     }
 59     cascade_name = "haarcascade_frontalface_alt2.xml"; 
 60     cascade = (CvHaarClassifierCascade*)cvLoad( cascade_name, 0, 0, 0 ); 
 61 
 62     if( !cascade ) 
 63     { 
 64         printf( "ERROR: Could not load classifier cascade\n" ); 
 65         return -1; 
 66     } 
 67 
 68     storage = cvCreateMemStorage(0); 
 69     cvNamedWindow( WND_RESULT, 1 ); 
 70 
 71     IplImage* frame = cvQueryFrame(capture);
 72     if(!frame)
 73     {
 74         return -1;
 75     }
 76 
 77     // Load skull image
 78     IplImage* skullImage = cvLoadImage("skull.jpg", CV_LOAD_IMAGE_UNCHANGED);
 79     if(!skullImage)
 80     {
 81         printf("ERROR: Can't load skull image.\n");
 82         return -1;
 83     }
 84     g_skullImage = cvCreateImage(cvGetSize(skullImage), skullImage->depth, 3);
 85     if(skullImage->nChannels != 3)
 86     {
 87         cvCvtColor(skullImage, g_skullImage, CV_GRAY2BGR);
 88     }
 89     else
 90     {
 91         cvCopy(skullImage, g_skullImage);
 92     }
 93 
 94     // Create trackbar
 95     cvCreateTrackbar("Switch", WND_RESULT, &g_trackbar_value, 
 96         g_trackbar_total, switch_callback );
 97     // Initialize Alpha-Blend's alpha
 98     g_alpha = (double)g_trackbar_value / g_trackbar_total;
 99 
100     char c;
101     while( 1 ) 
102     { 
103         frame = cvQueryFrame(capture);
104         if(!frame)
105         {
106             return -1;
107         }
108 
109         detect_and_draw( frame ); 
110 
111         c = cvWaitKey(50);
112         if(c == 27)
113         {
114             break;
115         }
116     }
117 
118     cvDestroyWindow(WND_RESULT); 
119     cvReleaseImage(&frame);
120     cvReleaseCapture(&capture);
121     cvReleaseImage(&skullImage);
122     cvReleaseImage(&g_skullImage);
123 
124     return 0; 
125 }
126 
127 
128 void detect_and_draw(IplImage* img ) 
129 { 
130     double scale=1.2; 
131     static CvScalar colors[] = { 
132         {{0,0,255}},{{0,128,255}},{{0,255,255}},{{0,255,0}}, 
133         {{255,128,0}},{{255,255,0}},{{255,0,0}},{{255,0,255}} 
134     };//Just some pretty colors to draw with
135 
136     //Image Preparation 
137     // 
138     IplImage* gray = cvCreateImage(cvSize(img->width,img->height),8,1); 
139     IplImage* small_img=cvCreateImage(cvSize(cvRound(img->width/scale),cvRound(img->height/scale)),8,1); 
140     cvCvtColor(img,gray, CV_BGR2GRAY); 
141     cvResize(gray, small_img, CV_INTER_LINEAR);
142 
143     cvEqualizeHist(small_img,small_img); //直方图均衡
144 
145     //Detect objects if any 
146     // 
147     cvClearMemStorage(storage); 
148     double t = (double)cvGetTickCount(); 
149     CvSeq* objects = cvHaarDetectObjects(small_img, 
150         cascade, 
151         storage, 
152         1.1, 
153         2, 
154         0/*CV_HAAR_DO_CANNY_PRUNING*/, 
155         cvSize(30,30));
156 
157     t = (double)cvGetTickCount() - t; 
158     printf( "detection time = %gms\n", t/((double)cvGetTickFrequency()*1000.) );
159 
160     //Loop through found objects and draw boxes around them 
161     for(int i=0;i<(objects? objects->total:0);++i) 
162     { 
163         CvRect* r=(CvRect*)cvGetSeqElem(objects,i); 
164 
165         CvRect r_scale = cvRect( r->x * scale, r->y * scale, r->width * scale, r->height * scale );
166         // 改变骷髅头图像大小
167         IplImage * skullResize = cvCreateImage( cvSize(r_scale.width, r_scale.height),
168             g_skullImage->depth, g_skullImage->nChannels );
169         cvResize(g_skullImage, skullResize, CV_INTER_LINEAR);
170 
171         // 将人脸检测区域用骷髅头图像代替
172         cvSetImageROI(img, r_scale);
173         // b -- Alpha blend 
174         printf("Alpha: %f\t", g_alpha);
175         cvAddWeighted( img, g_alpha, skullResize, 1.0 - g_alpha, 0.0, img);
176        /* This is a part
177         cvCopy(skullResize, img); */
178         cvResetImageROI(img);
179         cvReleaseImage(&skullResize);
180 
181      //   cvRectangle(img, cvPoint(r->x*scale,r->y*scale), cvPoint((r->x+r->width)*scale,(r->y+r->height)*scale), colors[i%8]); 
182     } 
183  /*   for( int i = 0; i < (objects? objects->total : 0); i++ ) 
184     { 
185         CvRect* r = (CvRect*)cvGetSeqElem( objects, i ); 
186         CvPoint center; 
187         int radius; 
188         center.x = cvRound((r->x + r->width*0.5)*scale); 
189         center.y = cvRound((r->y + r->height*0.5)*scale); 
190         radius = cvRound((r->width + r->height)*0.25*scale); 
191         cvCircle( img, center, radius, colors[i%8], 3, 8, 0 ); 
192     } */
193 
194     cvShowImage( WND_RESULT, img ); 
195     cvReleaseImage(&gray); 
196     cvReleaseImage(&small_img); 
197 }

运行结果（此时的alpha为0.2）：