使用python将检测到的人脸放入图像并显示在opencv的另一个窗口中

Question

我是图像处理和 opencv 的新手，但到目前为止，易于理解的功能和良好的文档使我能够尝试和理解一些级别的代码，如面部检测等。

现在，当我在网络摄像头视频流中检测到人脸时，程序会在人脸周围绘制一个正方形。现在我想要在脸部周围的正方形中创建那么多图像区域作为另一个图像。从我一直在做的事情来看，我得到了图像的一个矩形区域，其中甚至没有人脸。

我使用过 cv.GetSubRect() 并了解它的用途。例如：

img=cv.LoadImage("C:\opencv\me.jpg")
sub=cv.GetSubRect(img, (700,525,200,119))
cv.NamedWindow("result",1)
cv.ShowImage("result",sub)

• 给了我眼睛的裁剪照片。

但我无法在我的面部和眼睛检测程序中获取面部。 这是我所做的：

min_size = (17,17)
        #max_size = (30,30)

        image_scale = 2
        haar_scale = 2

        min_neighbors = 2
        haar_flags = 0

        # Allocate the temporary images
        gray = cv.CreateImage((image.width, image.height), 8, 1)
        smallImage = cv.CreateImage((cv.Round(image.width / image_scale),cv.Round (image.height / image_scale)), 8 ,1)
        #eyeregion = cv.CreateImage((cv.Round(image.width / image_scale),cv.Round (image.height / image_scale)), 8 ,1)
        #cv.ShowImage("smallImage",smallImage)

        # Convert color input image to grayscale
        cv.CvtColor(image, gray, cv.CV_BGR2GRAY)

        # Scale input image for faster processing
        cv.Resize(gray, smallImage, cv.CV_INTER_LINEAR)

        # Equalize the histogram
        cv.EqualizeHist(smallImage, smallImage)

        # Detect the faces
        faces = cv.HaarDetectObjects(smallImage, faceCascade, cv.CreateMemStorage(0),
        haar_scale, min_neighbors, haar_flags, min_size)
        #, max_size)

# If faces are found
        if faces:
                for ((x, y, w, h), n) in faces:
                # the input to cv.HaarDetectObjects was resized, so scale the
                # bounding box of each face and convert it to two CvPoints
                        pt1 = (int(x * image_scale), int(y * image_scale))
                        pt2 = (int((x + w) * image_scale), int((y + h) * image_scale))
                        cv.Rectangle(image, pt1, pt2, cv.RGB(255, 0, 0), 3, 4, 0)
                        face_region = cv.GetSubRect(image,(x,int(y + (h/4)),w,int(h/2)))
                        cv.ShowImage("face",face_region)


 cv.SetImageROI(image, (pt1[0],
                        pt1[1],
                        pt2[0] - pt1[0],
                        int((pt2[1] - pt1[1]) * 0.7)))
                eyes = cv.HaarDetectObjects(image, eyeCascade,
                cv.CreateMemStorage(0),
                eyes_haar_scale, eyes_min_neighbors,
                eyes_haar_flags, eyes_min_size)    

            if eyes:
                    # For each eye found
                    for eye in eyes:

                            eye[0][0],eye[0][1] are x,y co-ordinates of the top-left corner of detected eye
                            eye[0][2],eye[0][3] are the width and height of the cvRect of the detected eye region (i mean c'mon, that can be made out from the for loop of the face detection)
                            # Draw a rectangle around the eye


                            ept1 = (eye[0][0],eye[0][1])
                            ept2 = ((eye[0][0]+eye[0][2]),(eye[0][1]+eye[0][3]))

                            cv.Rectangle(image,ept1,ept2,cv.RGB(0,0,255),1,8,0) # This is working.. 


                            ea = ept1[0]
                            eb = ept1[1]
                            ec = (ept2[0]-ept1[0])
                            ed = (ept2[1]-ept1[1])

                            # i've tried multiplying with image_scale to get the eye region within
                            # the window of eye but still i'm getting just a top-left area of the 
                            # image, top-left to my head. It does make sense to multiply with image_scale right?




                            eyeregion=cv.GetSubRect(image, (ea,eb,ec,ed))
                            cv.ShowImage("eye",eyeregion)

Answer 1

我希望这段代码来自 OpenCV/samples/Python。您为 cv.GetSubRect 中的坐标提供的参数有一个小错误。请将上述程序的最后两行替换为：

a=pt1[0]
b=pt1[1]
c=pt2[0]-pt1[0]
d=pt2[1]-pt1[1]
face_region = cv.GetSubRect(image,(a,b,c,d))
cv.ShowImage("face",face_region) 

确保您没有错误检测或多重检测。