【BIGTREETECH PI开发板】+05.UVC（USB摄像头）应用：边沿检测和视频推流（zmj）

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【BIGTREETECH PI开发板】+05.UVC（USB摄像头）应用：边沿检测和视频推流（zmj） [复制链接]

 

【BIGTREETECH PI开发板】+05.UVC（USB摄像头）应用：边沿检测和视频推流（zmj）

1. 边沿检测

**BIGTREETECH PI开发板的USB摄像头（UVC）可以十分轻松的实现基于OPENCV的边沿检测功能。

//------UVC / USB-Camera
UVC通俗的讲就是USB摄像头，全称为USB Video Class，即：USB视频类，是一种为USB视频捕获设备定义的协议标准。

USB摄像头的视频流主要通过python调用OpenCV库完成对每一帧图像的边沿检测，参数调节通过滑动条实时调节以获取更好结果，按下ESC键退出测试程序（不得不说python是真的强大）：

//------基于OPENCV的摄像头视频边沿检测
//---指令（python2或者python3均可以）：
python3 ./edge.py 4
或者
python ./edge.py 4
//---指令中的参数”4“说明：
使用USB-Camera，它位于/dev/video4
//------依赖（根据错误提示安装对应的依赖库及以来组件）:
sudo apt install opencv*
sudo apt install libopencv*
sudo apt install gststream*
sudo apt install x11proto-video* python3-mecavideo multimedia-video libvideo* librust-gstreamer-video* gnome-video*

 

1.1 代码解析

代码功能说明：

//------代码功能说明：
a.导入必要的库：cv2、numpy、video 和 sys。
b.创建两个滑动条：cv.namedWindow('edge') 用来显示边缘检测的结果窗口，cv.createTrackbar('thrs1', 'edge', 2000, 5000, nothing) 和 cv.createTrackbar('thrs2', 'edge', 4000, 5000, nothing) 用来设置边缘检测的参数。
c.创建一个视频捕获对象：cap = video.create_capture(fn)，其中 fn 是指定的视频文件名。
d.在一个无限循环中，从视频捕获对象中读取帧数据：while True:。
e.将读取的帧数据转换为灰度图像：gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)。
f.对灰度图像进行边缘检测：edge = cv.Canny(gray, thrs1, thrs2, apertureSize=5)。
g.将原始图像和边缘检测结果合并：vis = img.copy()，然后将结果图像中非零像素的部分设为绿色：vis = np.uint8(vis/2.)，最后将结果图像显示出来：cv.imshow('edge', vis)。
h.监听窗口的关闭事件：ch = cv.waitKey(5)，如果按下了ESC键，则退出循环：if ch == 27:。
i.最后打印程序的文档字符串：print(__doc__)，并关闭所有窗口：cv.destroyAllWindows()。

//------完整代码：

#!/usr/bin/env python

from __future__ import print_function

import cv2 as cv
import numpy as np

# relative module
import video

# built-in module
import sys

def main():
    try:
        fn = sys.argv[1]
    except:
        fn = 0

    def nothing(*arg):
        pass

    cv.namedWindow('edge')
    cv.createTrackbar('thrs1', 'edge', 2000, 5000, nothing)
    cv.createTrackbar('thrs2', 'edge', 4000, 5000, nothing)

    cap = video.create_capture(fn)
    while True:
        _flag, img = cap.read()
        gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)
        thrs1 = cv.getTrackbarPos('thrs1', 'edge')
        thrs2 = cv.getTrackbarPos('thrs2', 'edge')
        edge = cv.Canny(gray, thrs1, thrs2, apertureSize=5)
        vis = img.copy()
        vis = np.uint8(vis/2.)
        vis[edge != 0] = (0, 255, 0)
        cv.imshow('edge', vis)
        ch = cv.waitKey(5)
        if ch == 27:
            break

    print('Done')


if __name__ == '__main__':
    print(__doc__)
    main()
    cv.destroyAllWindows()

 

1.2 测试效果

//------原图：

 

//------检测效果（参数合适）：

 

//------检测效果（低参）：丢失了很多检测细节

//------检测效果（高参）：此时引入了很多图像噪点

//------检测效果

uvc_video

 

 

2. 视频推流测试

BIGTREETECH PI开发板的USB摄像头（UVC）借助mjpg-streamer实现网页监控推流十分便捷。

2.1 下载编译

下载编译流程如下：

//------mjpg-streamer
//---下载
git clone https://github.com/jacksonliam/mjpg-streamer.git
cd mjpg-streamer
cd mjpg-streamer-experimental
gcc -v
//---依赖项/依赖库的安装
sudo apt install cmake
sudo apt-get install -y cmake libjpeg62-turbo-dev
//---编译安装mjpg-streamer
sudo apt install cmake
make all
make install
//---测试指令
sudo /usr/local/bin/mjpg_streamer -i "input_uvc.so -d /dev/video0 -r 1280x720 -y" -o "output_http.so"
部分测试配置（自动）如下所示：
	设备：/dev/video0
	分辨率：1280*720（720P）
	帧率：1帧/秒（此种情况下节省网络带宽，降低CPU占用率）
	格式：YUYV
	端口：8080
//---访问方式（PC端和手机端均OK）：
http://192.168.7.228:8080/?action=stream

 

//------编译安装：

//------温度变化：

 

2.2 测试结果

最终呈现效果是网页端实时刷新（1帧/秒）摄像头结果，统一局域网内在PC端和手机端均能正常查看推流效果。

//---测试指令
sudo /usr/local/bin/mjpg_streamer -i "input_uvc.so -d /dev/video0 -r 1280x720 -y" -o "output_http.so"
部分测试配置（自动）如下所示：
	设备：/dev/video0
	分辨率：1280*720（720P）
	帧率：1帧/秒（此种情况下节省网络带宽，降低CPU占用率）
	格式：YUYV
	端口：8080
//---访问方式（PC端和手机端均OK）：
http://192.168.7.228:8080/?action=stream

//------测试Log
biqu@BTT-CB1:~/zmj_ws/gst/mjpg-streamer/mjpg-streamer-experimental$ \
> ./mjpg_streamer -h
-----------------------------------------------------------------------
Usage: ./mjpg_streamer
  -i | --input "<input-plugin.so> [parameters]"
  -o | --output "<output-plugin.so> [parameters]"
 [-h | --help ]........: display this help
 [-v | --version ].....: display version information
 [-b | --background]...: fork to the background, daemon mode
-----------------------------------------------------------------------
Example #1:
 To open an UVC webcam "/dev/video1" and stream it via HTTP:
  ./mjpg_streamer -i "input_uvc.so -d /dev/video1" -o "output_http.so"
-----------------------------------------------------------------------
Example #2:
 To open an UVC webcam and stream via HTTP port 8090:
  ./mjpg_streamer -i "input_uvc.so" -o "output_http.so -p 8090"
-----------------------------------------------------------------------
Example #3:
 To get help for a certain input plugin:
  ./mjpg_streamer -i "input_uvc.so --help"
-----------------------------------------------------------------------
In case the modules (=plugins) can not be found:
 * Set the default search path for the modules with:
   export LD_LIBRARY_PATH=/path/to/plugins,
 * or put the plugins into the "/lib/" or "/usr/lib" folder,
 * or instead of just providing the plugin file name, use a complete
   path and filename:
   ./mjpg_streamer -i "/path/to/modules/input_uvc.so"
-----------------------------------------------------------------------
biqu@BTT-CB1:~/zmj_ws/gst/mjpg-streamer/mjpg-streamer-experimental$ \
> sudo /usr/local/bin/mjpg_streamer -i "input_uvc.so -d /dev/video0 -r 1280x720 -y" -o "output_http.so"
MJPG Streamer Version: git rev: 310b29f4a94c46652b20c4b7b6e5cf24e532af39
 i: Using V4L2 device.: /dev/video0
 i: Desired Resolution: 1280 x 720
 i: Frames Per Second.: -1
 i: Format............: YUYV
 i: JPEG Quality......: 80
 i: TV-Norm...........: DEFAULT
UVCIOC_CTRL_ADD - Error at Pan (relative): Inappropriate ioctl for device (25)
UVCIOC_CTRL_ADD - Error at Tilt (relative): Inappropriate ioctl for device (25)
UVCIOC_CTRL_ADD - Error at Pan Reset: Inappropriate ioctl for device (25)
UVCIOC_CTRL_ADD - Error at Tilt Reset: Inappropriate ioctl for device (25)
UVCIOC_CTRL_ADD - Error at Pan/tilt Reset: Inappropriate ioctl for device (25)
UVCIOC_CTRL_ADD - Error at Focus (absolute): Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Pan (relative): Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Tilt (relative): Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Pan Reset: Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Tilt Reset: Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Pan/tilt Reset: Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Focus (absolute): Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at LED1 Mode: Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at LED1 Frequency: Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Disable video processing: Inappropriate ioctl for device (25)
UVCIOC_CTRL_MAP - Error at Raw bits per pixel: Inappropriate ioctl for device (25)
 o: www-folder-path......: disabled
 o: HTTP TCP port........: 8080
 o: HTTP Listen Address..: (null)
 o: username:password....: disabled
 o: commands.............: enabled
 ^[^Csetting signal to stop //手动Ctrl+C退出//
 i: cleaning up resources allocated by input thread
 o: cleaning up resources allocated by server thread #00
force cancellation of threads and cleanup resources
done
biqu@BTT-CB1:~/zmj_ws/gst/mjpg-streamer/mjpg-streamer-experimental$

//------测试场景：PC端和手机端

//------执行测试：

 

//------测试结果：

<- 测试结果视频 ->

UVC-mjpg_streamer

 

 

//------end