树莓派3B+摄像头使用&picamera库

ゝ一纸荒年。 2023-02-17 03:43 25阅读 0赞

本文为参加无人驾驶车课程学习整理的笔记,致谢毕滢老师!

## 一.测试摄像头是否可用 ##

打开树莓派的终端程序,输入  
cd Desktop  
**raspistill -o imagejpg**     \#注意是字母o,而不是数字0  
摄像头会打开几秒  
拍一-张照片命名为image.jpg  
存在树莓派桌面

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FobWN3dA_size_16_color_FFFFFF_t_70][]

摄像头以最大分辨率拍摄一张照片  
**2592x1944**

### 二.命令行控制树莓派摄像头一raspistill ###

pi@raspberrypi:~/Desktop $ raspistill
    
    "raspistill" Camera App (commit 6e6a2c859a17 Tainted)
    
    Runs camera for specific time, and take JPG capture at end if requested
    
    usage: raspistill [options]
    
    Image parameter commands
    
    -q, --quality	: Set jpeg quality <0 to 100>
    -r, --raw	: Add raw bayer data to jpeg metadata
    -l, --latest	: Link latest complete image to filename <filename>
    -t, --timeout	: Time (in ms) before takes picture and shuts down (if not specified, set to 5s)
    -th, --thumb	: Set thumbnail parameters (x:y:quality) or none
    -d, --demo	: Run a demo mode (cycle through range of camera options, no capture)
    -e, --encoding	: Encoding to use for output file (jpg, bmp, gif, png)
    -x, --exif	: EXIF tag to apply to captures (format as 'key=value') or none
    -tl, --timelapse	: Timelapse mode. Takes a picture every <t>ms. %d == frame number (Try: -o img_%04d.jpg)
    -fp, --fullpreview	: Run the preview using the still capture resolution (may reduce preview fps)
    -k, --keypress	: Wait between captures for a ENTER, X then ENTER to exit
    -s, --signal	: Wait between captures for a SIGUSR1 or SIGUSR2 from another process
    -g, --gl	: Draw preview to texture instead of using video render component
    -gc, --glcapture	: Capture the GL frame-buffer instead of the camera image
    -bm, --burst	: Enable 'burst capture mode'
    -dt, --datetime	: Replace output pattern (%d) with DateTime (MonthDayHourMinSec)
    -ts, --timestamp	: Replace output pattern (%d) with unix timestamp (seconds since 1970)
    -fs, --framestart	: Starting frame number in output pattern(%d)
    -rs, --restart	: JPEG Restart interval (default of 0 for none)
    
    GL parameter commands
    
    -gs, --glscene	: GL scene square,teapot,mirror,yuv,sobel,vcsm_square
    -gw, --glwin	: GL window settings <'x,y,w,h'>
    
    Common Settings commands
    
    -?, --help	: This help information
    -w, --width	: Set image width <size>
    -h, --height	: Set image height <size>
    -o, --output	: Output filename <filename> (to write to stdout, use '-o -'). If not specified, no file is saved
    -v, --verbose	: Output verbose information during run
    -cs, --camselect	: Select camera <number>. Default 0
    -md, --mode	: Force sensor mode. 0=auto. See docs for other modes available
    -gps, --gpsdexif	: Apply real-time GPS information to output (e.g. EXIF in JPG, annotation in video (requires libgps.so.23)
    
    Preview parameter commands
    
    -p, --preview	: Preview window settings <'x,y,w,h'>
    -f, --fullscreen	: Fullscreen preview mode
    -op, --opacity	: Preview window opacity (0-255)
    -n, --nopreview	: Do not display a preview window
    -dn, --dispnum	: Display on which to display the preview window (dispmanx/tvservice numbering)
    
    Image parameter commands
    
    -sh, --sharpness	: Set image sharpness (-100 to 100)
    -co, --contrast	: Set image contrast (-100 to 100)
    -br, --brightness	: Set image brightness (0 to 100)
    -sa, --saturation	: Set image saturation (-100 to 100)
    -ISO, --ISO	: Set capture ISO
    -vs, --vstab	: Turn on video stabilisation
    -ev, --ev	: Set EV compensation - steps of 1/6 stop
    -ex, --exposure	: Set exposure mode (see Notes)
    -fli, --flicker	: Set flicker avoid mode (see Notes)
    -awb, --awb	: Set AWB mode (see Notes)
    -ifx, --imxfx	: Set image effect (see Notes)
    -cfx, --colfx	: Set colour effect (U:V)
    -mm, --metering	: Set metering mode (see Notes)
    -rot, --rotation	: Set image rotation (0-359)
    -hf, --hflip	: Set horizontal flip
    -vf, --vflip	: Set vertical flip
    -roi, --roi	: Set region of interest (x,y,w,d as normalised coordinates [0.0-1.0])
    -ss, --shutter	: Set shutter speed in microseconds
    -awbg, --awbgains	: Set AWB gains - AWB mode must be off
    -drc, --drc	: Set DRC Level (see Notes)
    -st, --stats	: Force recomputation of statistics on stills capture pass
    -a, --annotate	: Enable/Set annotate flags or text
    -3d, --stereo	: Select stereoscopic mode
    -dec, --decimate	: Half width/height of stereo image
    -3dswap, --3dswap	: Swap camera order for stereoscopic
    -ae, --annotateex	: Set extra annotation parameters (text size, text colour(hex YUV), bg colour(hex YUV), justify, x, y)
    -ag, --analoggain	: Set the analog gain (floating point)
    -dg, --digitalgain	: Set the digital gain (floating point)
    -set, --settings	: Retrieve camera settings and write to stdout
    
    
    Notes
    
    Exposure mode options :
    off,auto,night,nightpreview,backlight,spotlight,sports,snow,beach,verylong,fixedfps,antishake,fireworks
    
    Flicker avoid mode options :
    off,auto,50hz,60hz
    
    AWB mode options :
    off,auto,sun,cloud,shade,tungsten,fluorescent,incandescent,flash,horizon,greyworld
    
    Image Effect mode options :
    none,negative,solarise,sketch,denoise,emboss,oilpaint,hatch,gpen,pastel,watercolour,film,blur,saturation,colourswap,washedout,posterise,colourpoint,colourbalance,cartoon
    
    Metering Mode options :
    average,spot,backlit,matrix
    
    Dynamic Range Compression (DRC) options :
    off,low,med,high
    
    pi@raspberrypi:~/Desktop $

利用raspistill命令拍摄照片  
直接在终端输入raspistill即可查看所有raspistill的命令选项  
常用选项  
\-vf上下翻转  
\-hf左右翻转  
**1.raspistill -vf -hf -o image.jpg**  
![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FobWN3dA_size_16_color_FFFFFF_t_70 1][]

**2.间隔一定时间拍摄一张照片  
raspistill -t 30000 -tl 2000 -o image%04d.jpg   \#(表示4位数,不够4位时用0补充)**  
*raspistill -t 10000 -tl 2000 -o tp%2d.jpg(错,2前面少0,当图片数在个位时文件名会成为中间有空格的如tp 0.jpg,在后续操作中易出故障,虽然如此命名,也能拍照保存)  
(tp%2d.jpg,自动命名,2表示两位数,%和*d是不能少的,否则不能正常命名致停拍,tp 0.jpg)

(注意:

--------------------

### realvnc viewer连树莓派后文件管理器闪退:(网上查得是由于树莓派在读写文件的时候异常掉电所致) ###

**运行命令重装pcmanfm:**

**sudo apt-get install --reinstall pcmanfm**

*在调试树莓派摄像头的时候遇到,在桌面建一文件夹,储存拍摄图片,拍完之后,打开桌面文件夹时,闪退.*

树莓派关机最好使用命令进行关机

sudo poweroff

--------------------

### 三.命令行控制树莓派摄像头一 raspivid ###

使用树莓派摄像头拍摄视频  
**raspivid -o video.h264 -t 6000**  
拍摄- -段长度为6000ms的视频  
并存为video.h264  
播放保存下来的视频  
**omxplayer video.h264**

### 四.使用Python预览摄像头数据 --vnc设置 ###

点击树莓派任务栏右上角的VNC图标“  
点击选项菜单选择Options  
选择Troubleshooting  
打勾Enable experimental direct capture mode  
点OK保存

设置才能预览.

# 五.使用Python预览摄像头数据一 picamera库 #

关于picamera安装,参考:**picamera 1.10 教程及api中文简译（一)**([https://blog.csdn.net/talkxin/article/details/50499950][https_blog.csdn.net_talkxin_article_details_50499950])

### 直接用sudo pip install picamera就好了. ###

关于picamera的使用,参考:**python picamera入门**([https://blog.csdn.net/u012005313/article/details/51439448][https_blog.csdn.net_u012005313_article_details_51439448])

*注意，自己新建文件时,千万不能命名为picamera.py*

要想关闭红灯显示的话，可以设置camera.led = False。(其实好像没啥用)

from **picamera** import **PiCamera**  
import time  
**camera = PiCamera()**  
camera.**start\_preview()**  
time.sleep(10)  
camera.**stop\_preview()**

捕获图像  
camera.capture('image.jpg')

如果发现图像倒了,可以用rotation=180来调正.*这个rotation用过一次之后,就保持着,再次用的时候,不加这一句,效果也是正的,可能也是需要类似释放端口的操作.*

### 六.使用Python控制摄像头一一旋转   from picamera import PiCamera   import time   camera = PiCamera()   camera.rotation = 180   camera.start\_preview()   time.sleep(10)   camera.stop\_preview() ###

### 七.使用Python控制摄像头一翻转     ###

\#coding=utf-8  
from picamera import PiCamera  
import time  
camera = PiCamera()  
**camera.vflip = True  
camera.hflip = True**

'''  
vflip = True则上下翻转  
hflip = True则左右翻转  
'''  
camera.start\_preview()  
time.sleep(10)  
camera.stop\_preview()

### 八.使用Python控制摄像头一控制分辨率 ###

from picamera import PiCamera  
import time  
camera = PiCamera()  
**camera.resolution = (1280, 720)**  
camera.start\_preview()  
time.sleep(10)  
camera.stop\_preview()

静态**照片**最大分辨率为**2592x 1944**  
**视频**最大分辨率为**1920x1080**  
最小分辨率为**64x 64**

### 九.使用Python控制摄像头一控制亮度 ###

from picamera import PiCamera  
import time  
camera = PiCamera()  
**camera.brightness = 70**  
camera.start\_preview()  
time.sleep(10)  
camera.stop\_preview()

默认亮度是**50**  
可设置范围是**0~100**  
根据现场实际情况调节

### 十.使用Python控制摄像头一设定帧率 ###

from picamera import PiCamera  
import time  
camera = PiCamera()  
**camera.framerate = 30**  
camera.start\_preview()  
time.sleep(10)  
camera.stop\_preview()

小车在行驶时,实际使用约15帧.

### 十一.使用Python控制摄像头一控制对比度 ###

from picamera import PiCamera  
import time  
camera = PiCamera()  
camera.start\_preview()  
for i in range(100):  
**    camera.annotate\_text = "Contrast: %s" % i  
    camera.contrast = i**  
    time.sleep(0.1)  
camera.stop\_preview()

--------------------

关于%s,属于python格式化输出控制方面的知识,可参考:

**Python基本格式化输出**  
[https://blog.csdn.net/abby1559/article/details/79960249][https_blog.csdn.net_abby1559_article_details_79960249]

**Python格式化输出 %s %d %f**  
[https://blog.csdn.net/meccaendless/article/details/78042754?ops\_request\_misc=%257B%2522request%255Fid%2522%253A%2522159204806019195239853160%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fblog.%2522%257D&request\_id=159204806019195239853160&biz\_id=0&utm\_medium=distribute.pc\_search\_result.none-task-blog-2~blog~first\_rank\_v1~rank\_blog\_v1-1-78042754.pc\_v1\_rank\_blog\_v1&utm\_term=%E6%A0%BC%E5%BC%8F%E5%8C%96][https_blog.csdn.net_meccaendless_article_details_78042754_ops_request_misc_257B_2522request_255Fid_2522_253A_2522159204806019195239853160_2522_252C_2522scm_2522_253A_252220140713.130102334.pc_255Fblog._2522_257D_request_id_159204806019195239853160_biz_id_0_utm_medium_distribute.pc_search_result.none-task-blog-2_blog_first_rank_v1_rank_blog_v1-1-78042754.pc_v1_rank_blog_v1_utm_term_E6_A0_BC_E5_BC_8F_E5_8C_96]

**\[干货\]Python字符串格式化的四种姿势**  
[https://blog.csdn.net/ning13481193737/article/details/80948501][https_blog.csdn.net_ning13481193737_article_details_80948501]  
*(文章来源：[https://realpython.com/python-string-formatting/][https_realpython.com_python-string-formatting]*

*作者：Dan Bader*

*作者github：[https://github.com/dbader][https_github.com_dbader]*

*作者推特：[https://twitter.com/dbader\_org][https_twitter.com_dbader_org]*

*作者YouTube：[https://dbader.org/youtube][https_dbader.org_youtube]*

*作者官网：[https://dbader.org/][https_dbader.org])*

--------------------

**annotate\_text**可以在画面上添加文字

![20200613070219967.png][]

通过改变alpha的值，可以修改摄像头拍摄图像的透明度

camera.start_preview(alpha=200)sleep(10)camera.stop_preview()

alpha的取值范围为0-255

--------------------

### 十二.查看摄像头特效--image\_effect ###

#coding=utf-8
    from picamera import PiCamera
    import time
    camera = PiCamera()
    
    #camera.image_effect = 'cartoon'
    #查看所有特效
    camera.start_preview()
    i=1
    for effect in camera.IMAGE_EFFECTS:
        camera.image_effect = effect
        #%-20s,表示20个占位符,负号表示居左,s表示输出的是字符.
        camera.annotate_text="Effect:%-20s %-20s"% (effect,i)
        i+=1
        time.sleep(1)
    
    #time.sleep(10)
    camera.stop_preview()

### 查看摄像头特效第二种写法with: ###

#coding=utf-8
    #from picamera import PiCamera
    import picamera
    import time
    #camera = PiCamera()
    #摄像头特效
    #camera.image_effect = 'cartoon'
    #查看所有特效
    with picamera.PiCamera() as camera:
    	camera.start_preview()
    	i=0
    	tx_name=[]
    	for effect in camera.IMAGE_EFFECTS:
    		camera.image_effect = effect
    		#%-20s,表示20个占位符,负号表示居左,s表示输出的是字符.
    		i+=1
    		camera.annotate_text="Effect:%-20s %-20s"% (effect,i)
    		
    		#tx=tx.append([str(i),effect])
    		
    		#camera.capture('tx_%s%s.jpg'%(effect,i))
    		
    		time.sleep(1)
    		#time.sleep(10)
    		tx_name.append([i,effect])
    	print(tx_name)
    	#下面两行查看当前python版本
    	import sys
    	sys.version
    	camera.stop_preview()

--------------------

在搜查资料的过程中,看到有:

**树莓派摄像头使用常用命令及代码(0**[https://blog.csdn.net/oAlevel/article/details/98666162][https_blog.csdn.net_oAlevel_article_details_98666162]**)**,这篇文章代码与所学接近,整理较好,可参考.

from picamera import PiCamera
    import time
     
    camera = PiCamera()
    #左右上下翻转
    camera.vflip = True
    camera.hflip = True
    #控制分辨率
    #照片最大分辨率2592*1944
    #视频最大分辨率1920*1080
    #最小分辨率64*64
    camera.resolution = (1280,720)
    #控制亮度,默认亮度是50，范围是0-100
    camera.brightness = 70
    camera.framerate = 15
     
    for i in range(100):
        camera.annotate_text ="Contrast: %s"%i
        camera.contrast = i
        time.sleep(0.1)
    #摄像头特效
    camera.image_effect = 'cartoon'
    #查看所有特效
    for effect in camera.IMAGE_EFFECTS:
        camera.image_effect = effect
        camera.annotate_text="Effect:%s"% effect
        time.sleep(2)
     
    #保存照片
    camera.capture('cam_cap.jpg')
    camera.rotation = 180
    for i in range(5):
        time.sleep(1)
        camera.capture('cam_cap%s.jpg'%i)
     
    #保存视频
    camera.start_recording('video.h264')
    time.sleep(10)
    camera.stop_recording()
     
     
     
    camera.start_preview()
    time.sleep(10)
    camera.stop_preview()

#精简代码 自动配置资源访问语句
    with picamera.PiCamera() as camera:
        camera.start_recording('video.h264')
        camera.wait_recording(120)
        camera.stop_recording()
    with open(text.txt") as file:
        text_data = file.read()

关于picamera,可参考:[https://blog.csdn.net/talkxin/article/details/50504147?utm\_source=blogxgwz8][https_blog.csdn.net_talkxin_article_details_50504147_utm_source_blogxgwz8]

**camera每次调用后都需要通过close释放掉picamera的资源:**

import time  
import picamera

camera = picamera.PiCamera()  
try:  
    camera.start\_preview()  
    time.sleep(10)  
    camera.stop\_preview()  
finally:  
    camera.close()

python的**with**语句块，开启picamera执行会自动最后释放掉资源（据说是隐形调用close()）

import time  
import picamera

with picamera.PiCamera() as camera:  
    camera.start\_preview()  
    \# 将led指示灯设置为关闭  
    camera.led = False  
    \#实际测试红灯依然会亮  
    time.sleep(10)  
    camera.stop\_preview()

import picamera
    
    with picamera.PiCamera() as camera:
        # 将led指示灯设置为关闭
        camera.led = False
        # 这时拍照时指示灯不会亮起
        # 实际测试红灯依然会亮
        camera.capture('foo.jpg')

### 下面的例子重点是看 ###

camera.capture_sequence([
            'image%02d.jpg' % i
            for i in range(frames)
            ], use_video_port=True)
    这句,通过使用生成器表达式来提供要处理的文件名，而不是手动指定每个单独的文件名:(不换行形式如下)

camera.capture_sequence(['image%02d.jpg' % i for i in range(frames)], use_video_port=True)

注意这里输出文件名部分用的是**\[ \]**,但这样处理文件有局限,适合固定数量的.对于任意数量的,可用yield构造一个函数处理文件名.

#capture_sequence()它特别适合于快速捕获固定数量的帧，如以下示例所示，它捕获5张图像的“连拍”：
    #参阅https://picamera.readthedocs.io/en/release-1.13/recipes2.html#rapid-capture-and-processing
    import picamera
    import time
    
    frames = 60
    
    with picamera.PiCamera() as camera:
        camera.resolution = (1024, 768)
        camera.framerate = 30
        camera.start_preview()
        # Give the camera some warm-up time
        time.sleep(2)
        start = time.time()
        #给保存的文件起名，
        camera.capture_sequence(['image%02d.jpg' % i for i in range(frames)], use_video_port=True)
        finish = time.time()
    print('Captured %d frames at %.2ffps' % (
        frames,
        frames / (finish - start)))
    #上面这句形式也可不换行:print('Captured %d frames at %.2ffps' % (frames,frames / (finish - start)))

含yield的文件名生成器filenames(),每被访问一次生成输出一个文件名.

import time
    import picamera
    
    frames = 60
    
    def filenames():
        frame = 0
        while frame < frames:
            yield 'image%02d.jpg' % frame
            frame += 1
    
    with picamera.PiCamera(resolution='720p', framerate=30) as camera:
        camera.start_preview()
        # Give the camera some warm-up time
        time.sleep(2)
        start = time.time()
        camera.capture_sequence(filenames(), use_video_port=True)
        finish = time.time()
    print('Captured %d frames at %.2ffps' % (
        frames,
        frames / (finish - start)))

### 十三.录制视频文件--start\_recording ###

import picamera

with picamera.PiCamera() as camera:  
    camera.resolution = (640, 480)  
    camera.start\_recording('my\_video.h264')  
    camera.wait\_recording(60)  
    camera.stop\_recording()

请注意，这里使用的方法是wait\_recording，而不是time.sleep(),虽然功能上与time.sleep相同，但是wait\_recording会不断的监听错误的抛出（比如磁盘空间不足），一旦出现错误会立即暂停捕获图像，来处理当前的错误，而不是在sleep以后才进行处理。用time.sleep来替代wait\_recording方法的话，这种错误只能在stop\_recording()后才能被处理，在sleep期间不能及时处理.这可能导致未能及时处理错误，导致图像数据捕获失败。(参考：[https://blog.csdn.net/talkxin/article/details/50504601][https_blog.csdn.net_talkxin_article_details_50504601],4.11)

### 使用Python控制摄像头一 保存视频 ###

from picamera import PiCamera  
import time  
camera = PiCamera()  
camera.rotation = 180  
camera.start\_preview()  
**camera.start\_recording('video.h264')**  
time.sleep(10)  
**camera.stop\_recording()**  
camera.stop\_preview()

--------------------

关于picamera

在win10上安装picamera不成功,提示: File "C:\\Users\\38016\\AppData\\Local\\Temp\\pip-install-e\_9ojzf0\\picamera\\setup.py", line 113, in run  
        raise ValueError('Unable to open /proc/cpuinfo')  
    ValueError: Unable to open /proc/cpuinfo

.....

而/proc/cpuinfo等文件夹是linux下的,. win10h  不支持安装这个.

参阅:原文档:[https://picamera.readthedocs.io/en/release-1.13/][https_picamera.readthedocs.io_en_release-1.13]

\_Raspberry Pi: [https://www.raspberrypi.org/][https_www.raspberrypi.org]  
\_camera: [https://www.raspberrypi.org/learning/getting-started-with-picamera/][https_www.raspberrypi.org_learning_getting-started-with-picamera]  
\_PyPI: [https://pypi.python.org/pypi/picamera/][https_pypi.python.org_pypi_picamera]  
\_documentation: [https://picamera.readthedocs.io/][https_picamera.readthedocs.io]  
\_source code: [https://github.com/waveform80/picamera][https_github.com_waveform80_picamera]  
\_bug tracker: [https://github.com/waveform80/picamera/issues][https_github.com_waveform80_picamera_issues]  
\_BSD license: [https://opensource.org/licenses/BSD-3-Clause][https_opensource.org_licenses_BSD-3-Clause]

GETTING STARTED WITH PICAMERA（python picamera入门）(图文俱全,但部分内容较旧,可能与现版本不太一致,以实际为准,只作参考.)  
[http://blog.csdn.net/u012005313/article/details/51439448][http_blog.csdn.net_u012005313_article_details_51439448]

--------------------

### 十四.白平衡模式 ###

可以用camera.AWB\_MODES循环展示多个白平衡模式

camera.exposure\_mode可以设置曝光，可选参数有：off，auto，night，nightpreview，nightpreview，spotlight，sports，snow，beach，verylong，fixedfps，antishake，fireworks。预设是auto

import picamera
    from picamera import Color
    color=Color
    awb_mode_name=[]
    
    i=0
    with picamera.PiCamera() as camera:
    	camera.start_preview()
    	for awbmode in camera.AWB_MODES:
    		camera.awb_mode=awbmode
    		i+=1
    		camera.annotate_background = color('blue')
    		camera.annotate_foreground = color('yellow')
    		camera.annotate_text='Awb_mode:%s %i'%(awbmode,i)
    		awb_mode_name.append([i,awbmode])
    		time.sleep(1)
    	print(i)
    	print(awb_mode_name)
    	camera.stop_preview()

### 十五.曝光模式(参阅[https://picamera.readthedocs.io/en/release-1.13/api\_camera.html\#picamera.PiCamera.exposure\_mode][https_picamera.readthedocs.io_en_release-1.13_api_camera.html_picamera.PiCamera.exposure_mode]) ###

可以用camera.EXPOSURE\_MODES循环展示多个曝光模式

import picamera
    
    #查看曝光模式
    i=0
    from picamera import Color
    color=Color
    exposure_mode_name=[]
    with picamera.PiCamera() as camera:
    	camera.start_preview()
    	for exposuremode in camera.EXPOSURE_MODES:
    		camera.exposure_mode = exposuremode
    		i+=1
    		camera.annotate_background = color('blue')
    		camera.annotate_foreground = color('yellow')
    		camera.annotate_text='Awb_mode:%s %i'%(exposuremode,i)
    		exposure_mode_name.append([i,exposuremode])
    		time.sleep(1)
    	print(i)
    	print(exposure_mode_name)
    	camera.stop_preview()

--------------------

### 十六.高级一点的内容Custom outputs ###

对视频拍摄中每帧的处理构造一个自定义的输出类(参考[https://picamera.readthedocs.io/en/release-1.13/recipes2.html\#custom-outputs][https_picamera.readthedocs.io_en_release-1.13_recipes2.html_custom-outputs])

每拍摄一帧都会进来write处理

camera.start_recording(MyOut,format='mjpeg')
    
    import picamera
    
    class MyOutput(object):
        def __init__(self):
            self.size = 0
        def write(self, s):
            self.size += len(s)
        def flush(self):
            print('%d bytes would have been written' % self.size)
    
    with picamera.PiCamera() as camera:
        camera.resolution = (640, 480)
        camera.framerate = 60
        camera.start_recording(MyOutput(), format='h264')
        camera.wait_recording(10)
        camera.stop_recording()

### 十七.实时保存每张照片 ###

对视频拍摄中每一-帧做处理  
神奇的数字: ffd8  
代表一个JPG图片的开始  
参阅:[https://picamera.readthedocs.io/en/release-1.13/recipes2.html\#rapid-capture-and-processing][https_picamera.readthedocs.io_en_release-1.13_recipes2.html_rapid-capture-and-processing]下第4个例

#实时保存第张照片
    import io
    import time
    import picamera
    
    class SplitFrames(object):
        def __init__(self):
            self.frame_num = 0
            self.output = None
    
        def write(self, buf):
            if buf.startswith(b'\xff\xd8'):
                # Start of new frame; close the old one (if any) and
                # open a new output
                if self.output:
                    self.output.close()
                self.frame_num += 1
                self.output = io.open('image%02d.jpg' % self.frame_num, 'wb')
            self.output.write(buf)
    
    with picamera.PiCamera(resolution='720p', framerate=30) as camera:
        camera.start_preview()
        # Give the camera some warm-up time
        time.sleep(2)
        output = SplitFrames()
        start = time.time()
        camera.start_recording(output, format='mjpeg')
        camera.wait_recording(2)
        camera.stop_recording()
        finish = time.time()
    print('Captured %d frames at %.2ffps' % (
        output.frame_num,
        output.frame_num / (finish - start)))

### 十八.实时处理每张照片 ###

采用多线程的方式  
使用Python的threading  
每接受到一-帧,放入一个空闲的线程进行处理  
分析官方例程:

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FobWN3dA_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200612050021286.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FobWN3dA==,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FobWN3dA_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20200612051509919.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FobWN3dA==,size_16,color_FFFFFF,t_70
[https_blog.csdn.net_talkxin_article_details_50499950]: https://blog.csdn.net/talkxin/article/details/50499950
[https_blog.csdn.net_u012005313_article_details_51439448]: https://blog.csdn.net/u012005313/article/details/51439448
[https_blog.csdn.net_abby1559_article_details_79960249]: https://blog.csdn.net/abby1559/article/details/79960249
[https_blog.csdn.net_meccaendless_article_details_78042754_ops_request_misc_257B_2522request_255Fid_2522_253A_2522159204806019195239853160_2522_252C_2522scm_2522_253A_252220140713.130102334.pc_255Fblog._2522_257D_request_id_159204806019195239853160_biz_id_0_utm_medium_distribute.pc_search_result.none-task-blog-2_blog_first_rank_v1_rank_blog_v1-1-78042754.pc_v1_rank_blog_v1_utm_term_E6_A0_BC_E5_BC_8F_E5_8C_96]: https://blog.csdn.net/meccaendless/article/details/78042754?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522159204806019195239853160%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fblog.%2522%257D&request_id=159204806019195239853160&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2~blog~first_rank_v1~rank_blog_v1-1-78042754.pc_v1_rank_blog_v1&utm_term=%E6%A0%BC%E5%BC%8F%E5%8C%96
[https_blog.csdn.net_ning13481193737_article_details_80948501]: https://blog.csdn.net/ning13481193737/article/details/80948501
[https_realpython.com_python-string-formatting]: https://realpython.com/python-string-formatting/
[https_github.com_dbader]: https://github.com/dbader
[https_twitter.com_dbader_org]: https://twitter.com/dbader_org
[https_dbader.org_youtube]: https://dbader.org/youtube
[https_dbader.org]: https://dbader.org/
[20200613070219967.png]: https://img-blog.csdnimg.cn/20200613070219967.png
[https_blog.csdn.net_oAlevel_article_details_98666162]: https://blog.csdn.net/oAlevel/article/details/98666162
[https_blog.csdn.net_talkxin_article_details_50504147_utm_source_blogxgwz8]: https://blog.csdn.net/talkxin/article/details/50504147?utm_source=blogxgwz8
[https_blog.csdn.net_talkxin_article_details_50504601]: https://blog.csdn.net/talkxin/article/details/50504601
[https_picamera.readthedocs.io_en_release-1.13]: https://picamera.readthedocs.io/en/release-1.13/
[https_www.raspberrypi.org]: https://www.raspberrypi.org/
[https_www.raspberrypi.org_learning_getting-started-with-picamera]: https://www.raspberrypi.org/learning/getting-started-with-picamera/
[https_pypi.python.org_pypi_picamera]: https://pypi.python.org/pypi/picamera/
[https_picamera.readthedocs.io]: https://picamera.readthedocs.io/
[https_github.com_waveform80_picamera]: https://github.com/waveform80/picamera
[https_github.com_waveform80_picamera_issues]: https://github.com/waveform80/picamera/issues
[https_opensource.org_licenses_BSD-3-Clause]: https://opensource.org/licenses/BSD-3-Clause
[http_blog.csdn.net_u012005313_article_details_51439448]: http://www.voidcn.com/link?url=http://blog.csdn.net/u012005313/article/details/51439448
[https_picamera.readthedocs.io_en_release-1.13_api_camera.html_picamera.PiCamera.exposure_mode]: https://picamera.readthedocs.io/en/release-1.13/api_camera.html#picamera.PiCamera.exposure_mode
[https_picamera.readthedocs.io_en_release-1.13_recipes2.html_custom-outputs]: https://picamera.readthedocs.io/en/release-1.13/recipes2.html#custom-outputs
[https_picamera.readthedocs.io_en_release-1.13_recipes2.html_rapid-capture-and-processing]: https://picamera.readthedocs.io/en/release-1.13/recipes2.html#rapid-capture-and-processing