CV_CAP_PROP_POS_MSEC Current position of the video file in milliseconds.• CV_CAP_PROP_POS_FRAMES 0-based index of the frame to be decoded/captured next.• CV_CAP_PROP_POS_AVI_RATIO Relative position of the video file: 0 - start of the film, 1 - end of the film.• CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream.• CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream.• CV_CAP_PROP_FPS Frame rate.• CV_CAP_PROP_FOURCC 4-character code of codec.• CV_CAP_PROP_FRAME_COUNT Number of frames in the video file.• CV_CAP_PROP_FORMAT Format of the Mat objects returned by retrieve() .• CV_CAP_PROP_MODE Backend-specific value indicating the current capture mode.• CV_CAP_PROP_BRIGHTNESS Brightness of the image (only for cameras).• CV_CAP_PROP_CONTRAST Contrast of the image (only for cameras).• CV_CAP_PROP_SATURATION Saturation of the image (only for cameras).• CV_CAP_PROP_HUE Hue of the image (only for cameras).• CV_CAP_PROP_GAIN Gain of the image (only for cameras).• CV_CAP_PROP_EXPOSURE Exposure (only for cameras).• CV_CAP_PROP_CONVERT_RGB Boolean flags whether images should be converted to RGB. indicating• CV_CAP_PROP_WHITE_BALANCE Currently unsupported• CV_CAP_PROP_RECTIFICATION Rectification flag for stereo cameras (note: only supported by DC1394 v 2.x backend cur-rently)

#!/usr/bin/env python# -*- coding: utf-8 -*-import cv2import numpyfrom hlf_module import hlf_definefrom std_msgs.msg import Stringimport matplotlib.pyplot as plotimport xml.dom.minidomimport pylabimport rospyimport timecap = cv2.VideoCapture(0)cap.set(3,640) #設(shè)置分辨率cap.set(4,480)fps =cap.get(cv2.CAP_PROP_FPS) #獲取視頻幀數(shù)face_casade = cv2.CascadeClassifier('/opt/ros/kinetic/share/OpenCV-3.2.0-dev/haarcascades/haarcascade_frontalface_default.xml')Node_name='neck'#print cap.isOpened()class Detect_face():def __init__(self):'''定義節(jié)點(diǎn)Node_name(全局變量，而非具體名稱(chēng))'''self.err_pub=hlf_define.err_publisher()#錯(cuò)誤消息發(fā)布者rospy.init_node(Node_name,anonymous=True)self.neck_puber=rospy.Publisher(hlf_define.TOPIC_ACTION_NECK,String,queue_size=10)time.sleep(0.5)def head_motor_value(self):#解析xml文件 獲取舵機(jī)的范圍值dom = xml.dom.minidom.parse('/home/sb/catkin_ws/src/hlf_robot/scripts/hlf_action/head_value.xml')#得到文檔元素對(duì)象root = dom.documentElementitemlist = root.getElementsByTagName('login')item = itemlist[0]max_value=item.getAttribute("max")min_value=item.getAttribute("min")return max_value,min_valuedef detect_face(self):# get a frame#frame=cv2.imread('/home/sb/桌面/timg.jpeg')ret, frame = cap.read()gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)#轉(zhuǎn)成灰度圖#frame=cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)# show a framecv2.imshow("capture", gray)faces = face_casade.detectMultiScale(gray,1.2,5) #檢測(cè)人臉#print len(faces)if len(faces)>0:#判斷是否檢測(cè)到人臉result = ()max_face = 0value_x=0for (x,y,w,h) in faces:if (w*h > max_face): #檢測(cè)最大人臉max_face = w*hresult = (x,y,w,h)# max_face.append(width*height)x=result[0]w=result[2]z=value_x=value_x+x+w/2return zelse:return 1if __name__=='__main__':face=Detect_face()motor_max,motor_min= face.head_motor_value()x=[]i=1while True:try:z=face.detect_face()if z != 1:x.append(z)if len(x)>(fps-1):true_x = int(sum(x)/30)if(true_x>319):motor_value=int(1500+(int(motor_max)-1500)*(true_x-319)/320)#轉(zhuǎn)換成舵機(jī)值 頭部向左轉(zhuǎn)face.neck_puber.publish('%s'%motor_value)elif (true_x<319):motor_value=int(1500-(1500-int(motor_min))*(319-true_x)/320)face.neck_puber.publish('%s'%motor_value)x=[]else:if i==fps:face.neck_puber.publish('1500')i=1else:i +=1print (U'未檢測(cè)到人臉')if cv2.waitKey(1) & 0xFF == ord('q'):breakexcept Exception,e:print ecap.release()cv2.destroyAllWindows()