（7）树莓派读物USB摄像头

https://blog.csdn.net/qq_42403190/article/details/90453305

创建文件

camera.py

简单读取

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
import numpy as np
import cv2

cap = cv2.VideoCapture(0) # 从摄像头中取得视频

# 获取视频播放界面长宽
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH) + 0.5)
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT) + 0.5)

# 定义编码器 创建 VideoWriter 对象
fourcc = cv2.VideoWriter_fourcc(*'mp4v') # Be sure to use the lower case
out = cv2.VideoWriter('output.mp4', fourcc, 20.0, (width, height))

while(cap.isOpened()):
    #读取帧摄像头
    ret, frame = cap.read()
    if ret == True:
        #输出当前帧
        out.write(frame)

        cv2.imshow('My Camera',frame)

        #键盘按 Q 退出
        if (cv2.waitKey(1) & 0xFF) == ord('q'):
            break
    else:
        break

# 释放资源
out.release()
cap.release()
cv2.destroyAllWindows()

　　

处理融合

#!/usr/bin/env python3
# -*- coding:utf-8 -*-
import cv2
import numpy as np
name = 0
cap = cv2.VideoCapture(0)

cap.set(3,640)
cap.set(4,480)

ret, frame = cap.read()
rows, cols, channels = frame.shape
print(cols, rows, channels)

# 图像预处理
def img_p(img):

    # 灰度化
    gray_img = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

    # 平滑滤波
    blur = cv2.blur(gray_img, (3,3))

    # 二值化
    ret1, th1 = cv2.threshold(blur, 190, 255, cv2.THRESH_BINARY)

    # 透视变换
    b = 50
    pts1 = np.float32([[b, 0], [cols-b, 0], [0, rows], [cols, rows]])
    pts2 = np.float32([[0, 0], [cols, 0], [0, rows], [cols, rows]])
    M = cv2.getPerspectiveTransform(pts1, pts2)
    dst = cv2.warpPerspective(blur, M, (cols, rows))

    return dst

while(1):
        ret,frame = cap.read()
        dst = img_p(frame)
        cv2.imshow('usb camera', dst)

        k = cv2.waitKey(50)
        if (k == ord('q')):
            break
        elif(k == ord('s')):
                #name = input('name:')
                name += 1
                filename = r'./camera/' + str(name) + '.jpg'
                cv2.imwrite(filename, dst)
                print(filename)
                #break
cap.release()
cv2.destroyAllWindows()

　　

运行文件

python3 camera.py

　　

结果：