2、picamera库使用，开启，录像，截图，RGB格式转换
（1）开启摄像头
#!/usr/bin/python
# -*- coding:utf-8 -*-
import time
import picamera

with picamera.PiCamera() as camera:
    camera.resolution = (320, 240)
    camera.start_preview()

    time.sleep(10)

    camera.stop_preview()
运行此程序就可以启动树莓派摄像头10s，支持单纯的启动摄像头
设置了摄像头的分辨率是320*240

（2）开启摄像头并且进行录像将其保存到名为“file.h264”的文件中
#!/usr/bin/python
# -*- coding:utf-8 -*-
import time
import picamera

with picamera.PiCamera() as camera:
    camera.resolution = (320, 240)
    camera.start_preview()
    camera.start_recording("file.h264")
    camera.wait_recording(10)
    camera.stop_recording()
    camera.stop_preview()

（3）开启摄像头，采集一张照片

#!/usr/bin/python
# -*- coding:utf-8 -*-
import time
import picamera

with picamera.PiCamera() as camera:
    camera.resolution = (320, 240)
    camera.start_preview()
    time.sleep(2)
    camera.capture("face.jpg")#截图
    camera.stop_preview()
（4）开启摄像头，采集照片并在其上打印Exif标记
#!/usr/bin/python
# -*- coding:utf-8 -*-
import time
import picamera

with picamera.PiCamera() as camera:
    camera.resolution = (320, 240)
    camera.start_preview()
    time.sleep(2)
    camera.exif_tags['IFD0.Artist'] = 'Me!'
    camera.exif_tags['IFD0.Copyright'] = 'Copyright (c) 2013 Me!'
    camera.capture("face.jpg")
    camera.stop_preview()
（5）开启摄像头，采集一张图像，并通过RGE格式进行解码，生成一个numpy的图像阵列

#!/usr/bin/python
# -*- coding:utf-8 -*-
import time
import picamera
import picamera.array

with picamera.PiCamera() as camera:
    with picamera.array.PiRGBArray(camera) as stream:
        camera.resolution = (320, 240)
        camera.start_preview()
        time.sleep(2)
        camera.capture(stream, 'rgb')
        print stream.array.shape
        camera.stop_preview()