PYTHON+OPENCV Open the camera, save the video, the implementation of the photo function

In this section, the main learning is through

. Videocapture ()

Call the camera to read the image data, and use the

Cap.set (propid, value)  
Cap.get (propid)

Gets or changes the video properties.
Where the value of Propid is 0-18, 19 values are not each can be modified, each value corresponding to the properties and functions as follows:

Parameters	value	function/meaning
Cv_cap_prop_pos_msec	0	The current position of the video file (in milliseconds) or the video capture timestamp.
Cv_cap_prop_pos_frames	1	A 0-based index will be decoded/captured next frame.
Cv_cap_prop_pos_avi_ratio	2	The relative position of the video file: 0-The beginning of the movie, the movie's 1-end.
Cv_cap_prop_frame_width	3	The width of each frame of the video.
Cv_cap_prop_frame_height	4	The height of each frame of the video.
Cv_cap_prop_fps	5	The frame rate of the video.
Cv_cap_prop_fourcc	6	A 4-character Video encoder format.
Cv_cap_prop_frame_count	7	The number of frames in the video.
Cv_cap_prop_format	8	Byretrieve () returns the format of the Mat object.
Cv_cap_prop_mode	9	Indicates the backend-specific value of the current capture mode.
Cv_cap_prop_brightness	10	The brightness of the image (for the camera only).
Cv_cap_prop_contrast	11	Image contrast (for camera only).
Cv_cap_prop_saturation	12	The saturation of the image (for camera only).
Cv_cap_prop_hue	13	The hue of the image (for camera only).
Cv_cap_prop_gain	14	The gain of the image (for camera only).
Cv_cap_prop_exposure	15	Exposure (for cameras only).
Cv_cap_prop_convert_rgb	16	A Boolean flag that indicates whether the image should be converted to RGB.
Cv_cap_prop_white_balance	17	Currently does not support
Cv_cap_prop_rectification	18	Rectification mark for stereoscopic cameras (note: Only current support DC1394 v 2.x back end)

code as follows:

#coding: Utf-8import cv2import NumPy as NP "" "Function name: Cv2. Videocapture () function: Capture real-time image data return value via camera: Parameter one: Camera code, 0 is the default camera, notebook built-in camera is generally 0 or fill in the video name directly loaded local video file "" "Cap = Cv2. Videocapture (0) #创建一个 Videocapture object "" "Function Name: Cap.set (propid, value) function: Set video parameters. Setting the video's width and height values and the camera can only be set to 1280*720 and 640*480 when using the laptop built-in camera, even if the set value is different automatically corrected, and still return true return value: Boolean parameter one: need to set the parameters of the video parameter two: set the parameter Value "" "Ca P.set (3,480) cap.set (4,320) flag = 1; #设置一个标志, used to output video information "" "Function Name: cv2.isopened () Function: Returns a Boolean value (True/false), checks if initialization succeeded, returns successfully True return value: Boolean "" "while (Cap.isopened ()): #循环读取每一帧" "" Function Name: Cap.read () function: Returns two values first returns a Boolean value if the video read is correct, true if           Error, or false, can also be used to determine whether to the end of the video and return a value for each frame of the image, the value is a three-dimensional matrix universal Receive method is: Ret,frame = Cap.read ();  So ret store Boolean value, frame storage image If you use a variable to receive two values, such as frame = Cap.read () frame is a tuple, the original use of frame to change FRAME[1] return value: R1: Boolean R2: three-dimensional Matrix "" "Ret_flag of the image, Vshow = Cap.read () #gray = Cv2.cvtcolor (vshow,cv2.col Or_bgr2gray) #cv2. Imshow ("Gray", GRAY) cv2.imshow ("Capture_test", Vshow) #窗口显示, display named Capture_test k = Cv2.waitkey (1) & 0xFF #每帧数据延时 1ms, delay cannot be 0, otherwise read        The result will be a static frame if k = = Ord (' s '): #若检测到按键 ' s ', print the string "" "Function Name: Cap.get (propid) function: Query video parameter return value: None        Parameter one: Query the video parameters, some of which can be modified with cap.set () "" "Print (Cap.get (3));    Print (Cap.get (4)); elif k = = Ord (' q '): #若检测到按键 ' Q ', Exit Breakcap.release () #释放摄像头cv2. Destroyallwindows () #删除建立的全部窗口

PYTHON+OPENCV Open the camera, save the video, the implementation of the photo function