python - 将检测到的人脸放入图像中并使用python在opencv的另一个窗口中显示

Question

我是图像处理和 opencv 的新手，但到目前为止，易于理解的函数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。现在我想要图像的那么大区域，在脸部周围的正方形中，被创建为另一个图像。从我一直在做的事情来看，我得到了一个矩形区域，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)

• 给我眼睛的裁剪照片。

但是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 中的坐标给出的参数有一个小错误。请用以下内容替换上面程序的最后两行:

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) 

确保没有错误检测或多重检测。