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OpenCV でキャプチャーしたビデオをファイルに出力

参考
https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_gui/py_video_display/py_video_display.html

import cv2

cap = cv2.VideoCapture(0) 
w = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
h = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
fps = cap.get(cv2.CAP_PROP_FPS)
fourcc = cv2.VideoWriter_fourcc(*'MP4V') 
out = cv2.VideoWriter('out.mp4',fourcc, 30.0, (int(w),int(h))) 

while(True):
    ret, frame = cap.read()
    if ret==True:
        out.write(frame)       
        cv2.imshow('frame',frame)  
        keyboard = cv2.waitKey(30)
        if keyboard == 27:
            break
    else:
        break
cap.release()
out.release()  
cv2.destroyAllWindows()

import cv2

cap = cv2.VideoCapture(0)

w = cap.get(cv2.CAP_PROP_FRAME_WIDTH)

h = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)

fps = cap.get(cv2.CAP_PROP_FPS)

fourcc = cv2.VideoWriter_fourcc(*'MP4V')

out = cv2.VideoWriter('out.mp4',fourcc, 30.0, (int(w),int(h)))

while(True):

ret, frame = cap.read()

if ret==True:

out.write(frame)

cv2.imshow('frame',frame)

keyboard = cv2.waitKey(30)

if keyboard == 27:

break

else:

break

cap.release()

out.release()

cv2.destroyAllWindows()

OpenCV で背景差分

フレームを直接操作した場合

import cv2

ESC_KEY = 27
cap = cv2.VideoCapture(0) 
w = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
h = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
fps = cap.get(cv2.CAP_PROP_FPS)
avg = None

while True:
    ret, frame = cap.read()
    if frame is None:
        break
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    if avg is None:
        avg = gray.copy().astype("float")
        continue
    cv2.accumulateWeighted(gray, avg, 0.5)
    frameDelta = cv2.absdiff(gray, cv2.convertScaleAbs(avg))
    ret, thresh = cv2.threshold(frameDelta, 20, 255, cv2.THRESH_BINARY)

    cv2.imshow('frame', frame)
    cv2.imshow('thresh', thresh)

    keyboard = cv2.waitKey(30)
    if keyboard == ESC_KEY:
        break

cap.release()
cv2.destroyAllWindows()

import cv2

ESC_KEY = 27

cap = cv2.VideoCapture(0)

w = cap.get(cv2.CAP_PROP_FRAME_WIDTH)

h = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)

fps = cap.get(cv2.CAP_PROP_FPS)

avg = None

while True:

ret, frame = cap.read()

if frame is None:

break

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

if avg is None:

avg = gray.copy().astype("float")

continue

cv2.accumulateWeighted(gray, avg, 0.5)

frameDelta = cv2.absdiff(gray, cv2.convertScaleAbs(avg))

ret, thresh = cv2.threshold(frameDelta, 20, 255, cv2.THRESH_BINARY)

cv2.imshow('frame', frame)

cv2.imshow('thresh', thresh)

keyboard = cv2.waitKey(30)

if keyboard == ESC_KEY:

break

cap.release()

cv2.destroyAllWindows()

Numpy で書いてみた

import numpy as np 
import cv2

THRESHOLD = 100000
cap = cv2.VideoCapture(0) 
w = cap.get(cv2.CAP_PROP_FRAME_WIDTH)
h = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)
fps = cap.get(cv2.CAP_PROP_FPS)
if fps == 0:
    fps=30.0
  
old64 = np.zeros((int(h),int(w)),  dtype=np.int64)

while True:
    ret, frame = cap.read()
    if frame is None:
        break
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    gray64 = np.array(gray, np.int64)
    if old64 is not None:
        diff64 = abs(gray64-old64)
        old64 = gray64
    cv2.imshow('npframe', gray)
    res64=np.where(diff64 &gt; 50, 255, 0)
    motion = sum(sum(res64))
    if motion &gt; THRESHOLD:
        print("MOTION DETECTED:",str(motion))
    cv2.imshow('Frame', np.array(res64, np.uint8))

    keyboard = cv2.waitKey(30)
    if keyboard == ESC_KEY:
        break

cap.release()
out.release() 
cv2.destroyAllWindows()

import numpy as np

import cv2

THRESHOLD = 100000

cap = cv2.VideoCapture(0)

w = cap.get(cv2.CAP_PROP_FRAME_WIDTH)

h = cap.get(cv2.CAP_PROP_FRAME_HEIGHT)

fps = cap.get(cv2.CAP_PROP_FPS)

if fps == 0:

fps=30.0

old64 = np.zeros((int(h),int(w)), dtype=np.int64)

while True:

ret, frame = cap.read()

if frame is None:

break

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

gray64 = np.array(gray, np.int64)

if old64 is not None:

diff64 = abs(gray64-old64)

old64 = gray64

cv2.imshow('npframe', gray)

res64=np.where(diff64 > 50, 255, 0)

motion = sum(sum(res64))

if motion > THRESHOLD:

print("MOTION DETECTED:",str(motion))

cv2.imshow('Frame', np.array(res64, np.uint8))

keyboard = cv2.waitKey(30)

if keyboard == ESC_KEY:

break

cap.release()

out.release()

cv2.destroyAllWindows()

BackgroundSubtractorMOG でもっと簡単に書ける

背景差分
bgsegm は、Background-Foreground Segmentation Methods の略

import numpy as np
import cv2

cap = cv2.VideoCapture('out.mp4')

fgbg = cv2.bgsegm.createBackgroundSubtractorMOG()

while(1):
    ret, frame = cap.read()

    fgmask = fgbg.apply(frame)

    cv2.imshow('frame',frame)
    cv2.imshow('fgmask',fgmask)
    k = cv2.waitKey(30)
    if k == 27:
        break

cap.release()
cv2.destroyAllWindows()

import numpy as np

import cv2

cap = cv2.VideoCapture('out.mp4')

fgbg = cv2.bgsegm.createBackgroundSubtractorMOG()

while(1):

ret, frame = cap.read()

fgmask = fgbg.apply(frame)

cv2.imshow('frame',frame)

cv2.imshow('fgmask',fgmask)

k = cv2.waitKey(30)

if k == 27:

break

cap.release()

cv2.destroyAllWindows()

opencv Tutorial 顔認識

opencv Tutorial Cascade Classifier

import cv2 as cv
def detectAndDisplay(frame):
    frame_gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)
    frame_gray = cv.equalizeHist(frame_gray)
    <em>#-- Detect faces</em>
    faces = face_cascade.detectMultiScale(frame_gray)
    for (x,y,w,h) in faces:
        center = (x + w//2, y + h//2)
        frame = cv.ellipse(frame, center, (w//2, h//2), 0, 0, 360, (255, 0, 255), 4)
    cv.imshow('Capture - Face detection', frame)
face_cascade = cv.CascadeClassifier()
if not face_cascade.load('Haar-cascade/haarcascade_frontalface_alt.xml'):
    print('--(!)Error loading face cascade')
    exit(0)
cap = cv.VideoCapture(0)
if not cap.isOpened:
    print('--(!)Error opening video capture')
    exit(0)
while True:
    ret, frame = cap.read()
    if frame is None:
        print('--(!) No captured frame -- Break!')
        break
    detectAndDisplay(frame)
    if cv.waitKey(10) == 27:
        break

import cv2 as cv

def detectAndDisplay(frame):

frame_gray = cv.cvtColor(frame, cv.COLOR_BGR2GRAY)

frame_gray = cv.equalizeHist(frame_gray)

<em>#-- Detect faces</em>

faces = face_cascade.detectMultiScale(frame_gray)

for (x,y,w,h) in faces:

center = (x + w//2, y + h//2)

frame = cv.ellipse(frame, center, (w//2, h//2), 0, 0, 360, (255, 0, 255), 4)

cv.imshow('Capture - Face detection', frame)

face_cascade = cv.CascadeClassifier()

if not face_cascade.load('Haar-cascade/haarcascade_frontalface_alt.xml'):

print('--(!)Error loading face cascade')

exit(0)

cap = cv.VideoCapture(0)

if not cap.isOpened:

print('--(!)Error opening video capture')

exit(0)

while True:

ret, frame = cap.read()

if frame is None:

print('--(!) No captured frame -- Break!')

break

detectAndDisplay(frame)

if cv.waitKey(10) == 27:

break

opencv Video Tutorial

Getting Started with Videos より

import numpy as np 
import cv2 

cap = cv2.VideoCapture(0) 
while(True):
     # Capture frame-by-frame
     ret, frame = cap.read()
     # Our operations on the frame come here
     gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
     # Display the resulting frame
     cv2.imshow('frame',gray)

     if cv2.waitKey(1) &amp; 0xFF == ord('q'):
         break
 # When everything done, release the capture 
cap.release()
cv2.destroyAllWindows()

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

while(True):

# Capture frame-by-frame

ret, frame = cap.read()

# Our operations on the frame come here

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

# Display the resulting frame

cv2.imshow('frame',gray)

if cv2.waitKey(1) & 0xFF == ord('q'):

break

# When everything done, release the capture

cap.release()

cv2.destroyAllWindows()

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