Use Python and cameras to create simple Time-Delay photography and python camera latency

Use Python and cameras to create simple Time-Delay photography and python camera latency

"Delayed photography (English: Time-lapse photography) is a photography technique that uses normal or fast speed to play pictures at a low frame rate or video. In a delayed photography video, the process of slow changes of objects or scenes is compressed into a short period of time, showing a strange and wonderful scene that cannot be noticed by the naked eye at ordinary times. Delayed photography can be considered as a process opposite to high-speed photography. Delayed photography is usually applied to shooting urban scenery, natural scenery, astronomical phenomena, biological evolution, and other theme ."

-- Imported from Baidu encyclopedia

Grass Planting

Recently, I got a small gift for shopping. It was a fast-growing grass. I got it back and got it on my desk. Today, I plan to create a delayed photography. There is a very old 640xlarge camera in the office, so I have the following delayed photography animation (to upload and compress the image size):

1 import cv2 2 2 import time 3 4 interval = 20 # seconds 5 num_frames = 500 6 out_fps = 24 7 8 capture = cv2.VideoCapture (0) 9 size = (int (capture. get (cv2.cv. CV_CAP_PROP_FRAME_WIDTH), 10 int (capture. get (cv2.cv. CV_CAP_PROP_FRAME_HEIGHT) 11 video = cv2.VideoWriter ("time_lapse.avi", cv2.cv. CV_FOURCC ('I', '4', '2', '0'), out_fps, size) 12 13 # for low quality webcams, discard the starting unstable frames14 for I in xrange (42): 15 capture. read () 16 17 # capture frames to video18 for I in xrange (num_frames): 19 _, frame = capture. read () 20 video. write (frame) 21 22 # Optional, in case you need the frames for GIF or so23 filename = '{: 42.16.png '. format (I ). replace ('', '0') 24 cv2.imwrite (filename, frame) 25 26 print ('frame {} is captured. '. format (I) 27 time. sleep (interval) 28 29 video. release () 30 capture. release ()

Since it is a simple, delayed photography, the Code is also very simple. Set the shooting interval, the total number of frames, and the output frame rate. Use VideoCapture to get the image of the camera, and use VideoWriter to write the video, considering that some inferior cameras are unstable during initialization (for example, the old-fashioned camera I used), you can consider skipping the initial dozens of frames when capturing the image, during the capture process, you can also directly output images for easy GIF or other purposes.

Finally, the whole process of evaporation from water drops in an iron case is as follows: