camera.py

import cv2
# numpyは画像データの格納に必要です。
import numpy as np


def camera():
    cap = cv2.VideoCapture(0)
    isOpened = cap.isOpened()
    if not isOpened:
        return
    while True:
        result, frame = cap.read()
        if not result:
            return
        # 画像表示
        cv2.imshow('camera', frame)
        # キー入力受付
        key = cv2.waitKey(1)
        # 終了キー（EnterかEscで終了）
        if (key == 13) or (key == 27):
            break
    # カメラ終了
    cap.release()
    cv2.destroyAllWindows()

camera()

camera_2.py

import cv2

# VideoCapture オブジェクトを取得します
capture0 = cv2.VideoCapture(0)
capture1 = cv2.VideoCapture(1)

while(True):
    ret1, frame0 = capture0.read()
    ret2, frame1 = capture1.read()
    cv2.imshow('frame0',frame0)
    cv2.imshow('frame1',frame1)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

capture0.release()
capture1.release()
cv2.destroyAllWindows()

camera_m.py

import cv2

i = 0
flag = True
captures = []

# VideoCapture オブジェクトを取得します
while( flag ):
    capture = cv2.VideoCapture(i)
    ret, frame = capture.read()
    flag = ret
    if flag:
        i += 1
        captures.append( capture )

while(True):
    for i, capture in enumerate( captures ):
        ret, frame = capture.read()
        cv2.imshow( f'frame{i}', frame)

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

capture.release()
cv2.destroyAllWindows()