10 examples of 'cv2.videocapture(0)' in Python

46
def init_camera(self):
47
    # create the device
48
    self._device = hg.cvCreateCameraCapture(self._index)
49
50
    # Set preferred resolution
51
    cv.SetCaptureProperty(self._device, cv.CV_CAP_PROP_FRAME_WIDTH,
52
                            self.resolution[0])
53
    cv.SetCaptureProperty(self._device, cv.CV_CAP_PROP_FRAME_HEIGHT,
54
                            self.resolution[1])
55
56
    # and get frame to check if it's ok
57
    frame = hg.cvQueryFrame(self._device)
58
    # Just set the resolution to the frame we just got, but don't use
59
    # self.resolution for that as that would cause an infinite recursion
60
    # with self.init_camera (but slowly as we'd have to always get a frame).
61
    self._resolution = (int(frame.width), int(frame.height))
62
63
    #get fps
64
    self.fps = cv.GetCaptureProperty(self._device, cv.CV_CAP_PROP_FPS)
65
    if self.fps <= 0:
66
        self.fps = 1 / 30.
67
68
    if not self.stopped:
69
        self.start()

4
def main():
5
    capture = cv2.VideoCapture(0)
6
7
    if capture.isOpened():
8
        flag, frame = capture.read()
9
    else:
10
        flag = False
11
12
    while flag:
13
14
        flag, frame = capture.read()
15
16
        frame = abs(255 - frame)
17
18
        cv2.imshow("Video Camera", frame)
19
20
        if cv2.waitKey(1) & 0xFF == 27:
21
            break
22
23
    cv2.destroyAllWindows()

191
def startCamera(self, source_name):
192
193
    try:
194
        source = int(source_name)
195
    except:
196
        IkaUtils.dprint('%s: Looking up device name %s' %
197
                        (self, source_name))
198
        try:
199
            source_name = source_name.encode('utf-8')
200
        except:
201
            pass
202
203
        try:
204
            source = self.enumerateInputSources().index(source_name)
205
        except:
206
            IkaUtils.dprint("%s: Input '%s' not found" %
207
                            (self, source_name))
208
            return False
209
210
    IkaUtils.dprint('%s: initalizing capture device %s' % (self, source))
211
    self.realtime = True
212
    if self.isWindows():
213
        self.initCapture(700 + source)
214
    else:
215
        self.initCapture(0 + source)

22
def __enter__(self):
23
    self.cap = cv2.VideoCapture(self.dev)
24
    self.running = True 
25
    self.start()
26
    return self

42
def setupUsbCam(self):
43
    # initialize the camera and grab a reference to the raw camera capture
44
    self.rawCapture = cv2.VideoCapture(self.cameraNum)
45
46
    # wait for camera to warm up
47
    time.sleep(0.1)

19
def __init__(self, instance):
20
21
    # health
22
    self.healthy = False;
23
24
    # record instance
25
    self.instance = instance
26
    self.config_group = "camera%d" % self.instance
27
28
    # get image resolution
29
    self.img_width = sc_config.config.get_integer(self.config_group,'width',640)
30
    self.img_height = sc_config.config.get_integer(self.config_group,'height',480)
31
32
    # background image processing variables
33
    self.img_counter = 0        # num images requested so far
34
35
    # latest image captured
36
    self.latest_image = None
37
38
    # setup video capture
39
    self.camera = cv2.VideoCapture(self.instance)
40
41
    # check we can connect to camera
42
    if not self.camera.isOpened():
43
        print("failed to open webcam %d" % self.instance)

4
def main():
5
    capture = cv2.VideoCapture(0)
6
    eye_path = "../classifier/haarcascade_eye.xml"
7
    face_path = "../classifier/haarcascade_frontalface_default.xml"
8
9
    eye_cascade = cv2.CascadeClassifier(eye_path)
10
    face_cascade = cv2.CascadeClassifier(face_path)
11
12
    while (True):
13
        _, frame = capture.read()
14
15
        gray_frame = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
16
17
        eyes = eye_cascade.detectMultiScale(gray_frame, scaleFactor=1.05, minNeighbors=5, minSize=(10,10))
18
        faces = face_cascade.detectMultiScale(gray_frame, scaleFactor=1.05, minNeighbors=5, minSize=(40, 40))
19
20
        print("Number of eyes : " + str(len(eyes)))
21
        print("Number of faces : " + str(len(faces)))
22
23
        for (x, y, w, h) in eyes:
24
            cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 0, 255), 2)
25
26
        for (x, y, w, h) in faces:
27
            cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)
28
29
        cv2.imshow("Live Capture", frame)
30
31
        if cv2.waitKey(1) == 27:
32
            break
33
34
    cv2.destroyAllWindows()
35
    capture.release()

51
def __init__(self, source=None):
52
    self.previous_frame = None
53
    self.current_frame = None
54
    operating_system = os.uname()[-1]
55
56
    # if an rpi
57
    if source is None:
58
        if 'arm' in operating_system:
59
            self.camera_type = CameraType.pi
60
        else:
61
            self.camera_type = CameraType.cv
62
    else:
63
        self.camera_type = CameraType.custom
64
65
    if self.camera_type == CameraType.pi:
66
        self.camera = picamera.PiCamera()
67
        time.sleep(2)
68
        self.camera.resolution = (1280, 720)
69
        self.camera.framerate = Fraction(1, 6)
70
        self.camera.exposure_mode = 'off'
71
        self.camera.shutter_speed = 6000000
72
        self.camera.iso = 800
73
    elif self.camera_type == CameraType.cv:
74
        self.camera = cv2.VideoCapture(0)
75
    elif self.camera_type == CameraType.custom:
76
        self.camera = cv2.VideoCapture(source)

12
def __init__(self, video_file):
13
    vid = cv2.VideoCapture(video_file)
14
    # sometimes video capture seems to give the wrong dimensions read the
15
    # first image and try again
16
    # get video frame, stop program when no frame is retrive (end of file)
17
    ret, image = vid.read()
18
    vid.release()
19
        
20
    if ret:
21
        self.height = image.shape[0]
22
        self.width = image.shape[1]
23
        self.dtype = image.dtype
24
        self.vid = cv2.VideoCapture(video_file)
25
        self.video_file = video_file
26
    else:
27
        raise OSError(
28
            'Cannot get an image from %s.\n It is likely that either the file name is wrong, the file is corrupt or OpenCV was not installed with ffmpeg support.' %
29
            video_file)

18
def detect():
19
    face = cv2.CascadeClassifier("data/haarcascade_frontalface_default.xml")
20
    eye = cv2.CascadeClassifier("data/haarcascade_eye.xml")
21
22
    camera = cv2.VideoCapture(0) # 0表示使用第一个摄像头
23
24
    while True:
25
        ret, frame = camera.read() # ret:布尔值表示是否读取帧成功, frame为帧本身
26
        gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY) # 检测人脸需要基于灰度图像
27
28
        faces = face.detectMultiScale(gray, 1.3, 5) 
29
        # faces = face.detectMultiScale(gray, scaleFactor, minNeighbors)
30
        # scaleFactor: 每次迭代时图像的压缩率
31
        # minNeighbors: 每个人脸矩形保留近似邻近数目的最小值
32
33
        for x,y,w,h in faces:
34
            img = cv2.rectangle(frame, (x,y), (x + w, y + h), (250, 0, 0), 2)
35
36
            eye_area = gray[y : y + h, x : x + w]
37
            eyes = eye.detectMultiScale(eye_area, 1.03, 5, 0, (40, 40))
38
            # eye.detectMultiScale(eye_area, 1.03, 5, 0, (40, 40))中
39
            # (40, 40)参数目的是为了消除假阳性(false positive)的影响， 将眼睛搜索的最小尺寸现实为40x40
40
            for ex,ey,ew,eh in eyes:
41
                cv2.rectangle(frame, (x + ex, y + ey),(x + ex + ew, y + ey + eh), (0, 255, 0), 2)
42
43
        cv2.imshow("face", frame)
44
        if cv2.waitKey(1000 // 12) & 0xff == ord("q"):
45
            break
46
    camera.release()
47
    cv2.destroyAllWindows()