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I was wondering if I am going about this the right way, or if there is a way that is much more efficient.

I am trying to look for an image inside of a video, like on every single frame of the video this image might be contained somewhere inside of it (its not the full size frame, just a small one).

Currently pulling the video into pictures as such:

import cv2
vidcap = cv2.VideoCapture('My_Video.mp4')
success,image = vidcap.read()
count = 0
success = True
while success:
  success,image = vidcap.read()
  print ('Read a new frame: ', success)
  cv2.imwrite("frame%d.jpg" % count, image)     # save frame as JPEG file
  count += 1

Then looping through them all as such:

import cv2
import numpy as np
from matplotlib import pyplot as plt

img_rgb = cv2.imread('frame1.png')
img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)
template = cv2.imread('small_icon_I_am_looking_for.png',0)
w, h = template.shape[::-1]

res = cv2.matchTemplate(img_gray,template,cv2.TM_CCOEFF_NORMED)
threshold = 0.8
loc = np.where( res >= threshold)
for pt in zip(*loc[::-1]):
    cv2.rectangle(img_rgb, pt, (pt[0] + w, pt[1] + h), (0,0,255), 2)

cv2.imwrite('res.png',img_rgb)

Is there a way to perhaps skip the saving of the pictures? I am doing this across thousands of hours of video, and saving and deleting every frame I feel will use a ton of time that might not be needed. Any ideas how I can search for this without needing to save the picture each time? This is an example of what I mean, say there was a video of super mario being played, it looks for this coin:

Coin

and detects it as such:

Coin detected

This currently works, but just looking for a better way.

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1 回答 1

3

如果我没有误解你，下面应该工作。总体而言，您的代码编写得很好，只需进行最少的更改即可完成您的要求。由于 while 循环的结构，您丢弃第一帧也存在问题。避免这种情况的一个好方法是循环和一个 half/while True 构造：

import cv2
import numpy as np
from matplotlib import pyplot as plt

def process_img(img_rgb, template, count):
    img_gray = cv2.cvtColor(img_rgb, cv2.COLOR_BGR2GRAY)

    w, h = template.shape[::-1]

    res = cv2.matchTemplate(img_gray,template,cv2.TM_CCOEFF_NORMED)
    threshold = 0.8
    loc = np.where( res >= threshold)
    for pt in zip(*loc[::-1]):
        cv2.rectangle(img_rgb, pt, (pt[0] + w, pt[1] + h), (0,0,255), 2)

    # This will write different res.png for each frame. Change this as you require
    cv2.imwrite('res{0}.png'.format(count),img_rgb)   


def main():
    vidcap = cv2.VideoCapture('My_Video.mp4')
    template = cv2.imread('small_icon_I_am_looking_for.png',0)  # open template only once
    count = 0
    while True:
      success,image = vidcap.read()
      if not success: break         # loop and a half construct is useful
      print ('Read a new frame: ', success)
      process_image(image, template, count)
      count += 1
于 2016-12-26T23:25:21.197 回答