Question

我尝试使用此代码在视频上绘制动画点

require(microbenchmark)

pmax_new <- function(a, b) {
  elsb <- which(a > b)
  b[elsb] <- a[elsb]
  b
}

a <- c(3,3,5,NA,1)
b <- c(2,4,6,0,NA)
s <- 20
microbenchmark( pmax(rep(a, s), rep(b, s)), times = 1E6 )
microbenchmark( pmax_new(rep(a, s), rep(b, s)), times = 1E6)

但是整个动画发生在单个帧上，而不是连续帧上连续。另外，我想在红色球/圆圈中添加一定程度的抖动/随机性。如何实现两者？

Answer 1

Ahh通过调整睡眠计时器并跳过帧来解决了

from collections import deque
from imutils.video import VideoStream
import numpy as np
import cv2
import imutils
import time

vs = cv2.VideoCapture('/media/intercept.mp4')
pts = deque(maxlen=64) #buffer size

i=0
ct=0
# keep looping
while True:
    ret,frame = vs.read()
    # resize the frame, blur it, and convert it to the HSV
    # color space
    frame = imutils.resize(frame, width=600)
    blurred = cv2.GaussianBlur(frame, (11, 11), 0)
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

    i+=2
    ct+=10
    #for i in range(10,260,20):
        #time.sleep(0.5)     #To visualise dots one by one
    if ct%10==0:
        cv2.circle(frame,(i, i),10, (0,0,255), -1) #draw circle
        #cv2.imshow('frame',frame)     #show output image
        if cv2.waitKey(1) == ord('q'):
            break

    cv2.imshow("Frame", frame)
    key = cv2.waitKey(1) & 0xFF
    # if the 'q' key is pressed, stop the loop
    if key == ord("q"):
        break

cv2.destroyAllWindows()
vs.release()

如何使用Open CV在视频中绘制虚线

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