【树莓派5 测评】 + 11.USB-Camera功能测试（zmj）
【树莓派5 测评】 + 11.USB-Camera功能测试（zmj）本篇主要介绍在树莓派5开发板测试USB-Camera（UVC）的流程。//------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。---------------------------以下为正文---------------------------1. 摄像头接口和设备摄像头设备位于” /dev/video*“（此处仅连接了USB摄像头）。//------查看摄像头设备节点
//---测试指令
a.通过设备列表查看
ls -la /dev/video*
b.通过v4l2-ctl工具查看
v4l2-ctl --list-devices
c.通过media0检查有效摄像头节点
media-ctl -d /dev/media3 -p
d.无效指令：libcamera-hello无法检测UVC，貌似支持CSI接口摄像头
libcamera-hello --list-cameras
//---检查结果
USB 2.0 Camera: USB Camera (usb-xhci-hcd.0-2.1):
/dev/video0
/dev/video1
/dev/media3
//------示例Log信息
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ ls -la /dev/video*
crw-rw----+ 1 root video 81, 18 Apr 26 18:15 /dev/video19
crw-rw----+ 1 root video 81,0 Apr 26 18:15 /dev/video20
crw-rw----+ 1 root video 81,1 Apr 26 18:15 /dev/video21
crw-rw----+ 1 root video 81,2 Apr 26 18:15 /dev/video22
crw-rw----+ 1 root video 81,3 Apr 26 18:15 /dev/video23
crw-rw----+ 1 root video 81,4 Apr 26 18:15 /dev/video24
crw-rw----+ 1 root video 81,5 Apr 26 18:15 /dev/video25
crw-rw----+ 1 root video 81,6 Apr 26 18:15 /dev/video26
crw-rw----+ 1 root video 81,7 Apr 26 18:15 /dev/video27
crw-rw----+ 1 root video 81,8 Apr 26 18:15 /dev/video28
crw-rw----+ 1 root video 81,9 Apr 26 18:15 /dev/video29
crw-rw----+ 1 root video 81, 10 Apr 26 18:15 /dev/video30
crw-rw----+ 1 root video 81, 11 Apr 26 18:15 /dev/video31
crw-rw----+ 1 root video 81, 12 Apr 26 18:15 /dev/video32
crw-rw----+ 1 root video 81, 13 Apr 26 18:15 /dev/video33
crw-rw----+ 1 root video 81, 14 Apr 26 18:15 /dev/video34
crw-rw----+ 1 root video 81, 15 Apr 26 18:15 /dev/video35
crw-rw----+ 1 root video 81, 16 Apr 26 18:15 /dev/video36
crw-rw----+ 1 root video 81, 17 Apr 26 18:15 /dev/video37
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ lsusb
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 004: ID 1b3f:2008 Generalplus Technology Inc. Usb Audio Device
Bus 001 Device 003: ID 0c45:6362 Microdia USB 2.0 Camera
Bus 001 Device 002: ID 1a40:0801 Terminus Technology Inc. USB 2.0 Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ dmesg | tail -23
usb 1-2: new high-speed USB device number 2 using xhci-hcd
usb 1-2: New USB device found, idVendor=1a40, idProduct=0801, bcdDevice= 1.00
usb 1-2: New USB device strings: Mfr=0, Product=1, SerialNumber=0
usb 1-2: Product: USB 2.0 Hub
hub 1-2:1.0: USB hub found
hub 1-2:1.0: 4 ports detected
usb 1-2.1: new high-speed USB device number 3 using xhci-hcd
usb 1-2.1: New USB device found, idVendor=0c45, idProduct=6362, bcdDevice= 0.00
usb 1-2.1: New USB device strings: Mfr=2, Product=1, SerialNumber=0
usb 1-2.1: Product: USB 2.0 Camera
usb 1-2.1: Manufacturer: Sonix Technology Co., Ltd.
usb 1-2.3: new full-speed USB device number 4 using xhci-hcd
usb 1-2.3: config 1 has an invalid interface number: 3 but max is 2
usb 1-2.3: config 1 has no interface number 1
usb 1-2.3: New USB device found, idVendor=1b3f, idProduct=2008, bcdDevice= 1.00
usb 1-2.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
usb 1-2.3: Product: Usb Audio Device
usb 1-2.3: Manufacturer: Generalplus
input: Generalplus Usb Audio Device as /devices/platform/axi/1000120000.pcie/1f00200000.usb/xhci-hcd.0/usb1/1-2/1-2.3/1-2.3:1.3/0003:1B3F:2008.0001/input/input5
hid-generic 0003:1B3F:2008.0001: input,hidraw0: USB HID v2.01 Device on usb-xhci-hcd.0-2.3/input3
usb 1-2.1: Found UVC 1.00 device USB 2.0 Camera (0c45:6362)
usbcore: registered new interface driver uvcvideo
usbcore: registered new interface driver snd-usb-audio
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ ls -la /dev/video*
crw-rw----+ 1 root video 81, 19 Apr 28 11:25 /dev/video0
crw-rw----+ 1 root video 81, 20 Apr 28 11:25 /dev/video1
crw-rw----+ 1 root video 81, 18 Apr 26 18:15 /dev/video19
crw-rw----+ 1 root video 81,0 Apr 26 18:15 /dev/video20
crw-rw----+ 1 root video 81,1 Apr 26 18:15 /dev/video21
crw-rw----+ 1 root video 81,2 Apr 26 18:15 /dev/video22
crw-rw----+ 1 root video 81,3 Apr 26 18:15 /dev/video23
crw-rw----+ 1 root video 81,4 Apr 26 18:15 /dev/video24
crw-rw----+ 1 root video 81,5 Apr 26 18:15 /dev/video25
crw-rw----+ 1 root video 81,6 Apr 26 18:15 /dev/video26
crw-rw----+ 1 root video 81,7 Apr 26 18:15 /dev/video27
crw-rw----+ 1 root video 81,8 Apr 26 18:15 /dev/video28
crw-rw----+ 1 root video 81,9 Apr 26 18:15 /dev/video29
crw-rw----+ 1 root video 81, 10 Apr 26 18:15 /dev/video30
crw-rw----+ 1 root video 81, 11 Apr 26 18:15 /dev/video31
crw-rw----+ 1 root video 81, 12 Apr 26 18:15 /dev/video32
crw-rw----+ 1 root video 81, 13 Apr 26 18:15 /dev/video33
crw-rw----+ 1 root video 81, 14 Apr 26 18:15 /dev/video34
crw-rw----+ 1 root video 81, 15 Apr 26 18:15 /dev/video35
crw-rw----+ 1 root video 81, 16 Apr 26 18:15 /dev/video36
crw-rw----+ 1 root video 81, 17 Apr 26 18:15 /dev/video37
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ libcamera-hello --list-cameras
No cameras available!
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ v4l2-ctl --list-devices
pispbe (platform:1000880000.pisp_be):
/dev/video20
/dev/video21
/dev/video22
/dev/video23
/dev/video24
/dev/video25
/dev/video26
/dev/video27
/dev/video28
/dev/video29
/dev/video30
/dev/video31
/dev/video32
/dev/video33
/dev/video34
/dev/video35
/dev/video36
/dev/video37
/dev/media0
/dev/media1
rpivid (platform:rpivid):
/dev/video19
/dev/media2
USB 2.0 Camera: USB Camera (usb-xhci-hcd.0-2.1):
/dev/video0
/dev/video1
/dev/media3
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ media-ctl -d /dev/media3 -p
Media controller API version 6.6.20
Media device information
------------------------
driver uvcvideo
model USB 2.0 Camera: USB Camera
serial
bus info usb-xhci-hcd.0-2.1
hw revision 0x0
driver version6.6.20
Device topology
- entity 1: USB 2.0 Camera: USB Camera (1 pad, 1 link)
type Node subtype V4L flags 1
device node name /dev/video0
pad0: Sink
<- "Extension 3":1
- entity 4: USB 2.0 Camera: USB Camera (0 pad, 0 link)
type Node subtype V4L flags 0
device node name /dev/video1
- entity 8: Extension 3 (2 pads, 2 links)
type V4L2 subdev subtype Unknown flags 0
pad0: Sink
<- "Processing 2":1
pad1: Source
-> "USB 2.0 Camera: USB Camera":0
- entity 11: Processing 2 (2 pads, 2 links)
type V4L2 subdev subtype Unknown flags 0
pad0: Sink
<- "Camera 1":0
pad1: Source
-> "Extension 3":0
- entity 14: Camera 1 (1 pad, 1 link)
type V4L2 subdev subtype Sensor flags 0
pad0: Source
-> "Processing 2":0
zhaomeijing@raspberrypi5:~/workspace/09_uvc$//------USB摄像头状态2. USB摄像头测试将USB摄像头插入开发板，将自动安装 uvc 添加设备节点。USB 2.0 Camera: USB Camera (usb-xhci-hcd.0-2.1):/dev/video0/dev/video1/dev/media3USB摄像头测试内容包括设备节点检测、视频、拍照，测试指令如下：//------USB-Camera（某宝几十块买的USB摄像头，支持1080P）
a.确认USB摄像头的设备节点，此处为/dev/video0。
v4l2-ctl --list-devices
b.查看摄像头支持的格式与分辨率
v4l2-ctl --list-formats-ext -d /dev/video0
c.摄像头预览（视频640 x 480）
gst-launch-1.0 v4l2src device=/dev/video0 ! \
"video/x-raw, width=640, Height=480, framerate=(fraction)30/1" ! \
queue ! glimagesink
d.摄像头预览（视频1920 x 1080）
gst-launch-1.0 v4l2src device=/dev/video0 ! \
video/x-raw,format=YUY2,width=1920,height=1080 ! \
queue ! glimagesink
e.摄像头预览（拍照）
gst-launch-1.0 v4l2src device=/dev/video0 num-buffers=3 ! \
jpegenc ! filesink location=~/pic_of_video0.jpg//------测试场景//------USB摄像头测试正常（此处展示的是视频捕捉的测试场景；需要注意，分辨率越高，需要的响应时间越长）
3. 边沿检测USB摄像头的视频流主要通过python调用OpenCV库完成对每一帧图像的边沿检测，参数调节通过滑动条实时调节以获取更好结果，按下ESC键退出测试程序（不得不说python是真的强大）：//------基于OPENCV的摄像头视频边沿检测
//---指令（python2或者python3均可以）：
python3 ./edge.py 0
或者
python ./edge.py 0
//---指令中的参数”0“说明：
使用USB-Camera，它位于/dev/video0
//------依赖（根据错误提示安装对应的依赖库及以来组件）:
sudo apt install opencv*
sudo apt install libopencv*
sudo apt install gststream*
sudo apt install python3-opencv*
//---Log信息：
zhaomeijing@raspberrypi5:~/workspace/09_uvc$ python3 ./edge.py 0
Video capture sample.
Sample shows how VideoCapture class can be used to acquire video
frames from a camera of a movie file. Also the sample provides
an example of procedural video generation by an object, mimicking
the VideoCapture interface (see Chess class).
'create_capture' is a convenience function for capture creation,
falling back to procedural video in case of error.
Usage:
video.py [--shotdir <shot path>] ...'
sourceN is an
- integer number for camera capture
- name of video file
- synth:<params> for procedural video
Synth examples:
synth:bg=lena.jpg:noise=0.1
synth:class=chess:bg=lena.jpg:noise=0.1:size=640x480
Keys:
ESC - exit
SPACE- save current frame to <shot path> directory
[ WARN:0@1.380] global ./modules/videoio/src/cap_gstreamer.cpp (1405) open OpenCV | GStreamer warning: Cannot query video position: status=0, value=-1, duration=-1
Done
zhaomeijing@raspberrypi5:~/workspace/09_uvc$
3.1 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
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 = (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()3.2 测试效果基于USB-Camera的边沿检测测试结果如图所示：
//------end
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