受苦笔记之Ubuntu 18.04 ros相机标定

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Ubuntu 18.04 相机标定

之前用ubuntu 16.04想做相机标定但是一直出错，所以换了系统后我又回来折腾了

安装ROS就不说了

主要是ROS下的usb_cam程序包，之前一直在报错的我，终于换了系统后成功了。。。。

usb_cam下载网址

棋盘标定板下载

都说可以在终端直接安装，但是我的不知道为什么死活找不到包，所以只能在GitHub上通过源码安装了

1.下载源码

tanjx@tanjx-GL553VW:~/catkin_ws/src$ git clone https://github.com/ros-drivers/usb_cam

2.编译

tanjx@tanjx-GL553VW:~/catkin_ws/src$ cd ..
tanjx@tanjx-GL553VW:~/catkin_ws$ catkin_make

3.运行launch文件

tanjx@tanjx-GL553VW:~$ roslaunch usb_cam usb_cam-test.launch

错误1：

RLException: [usb_cam-test.launch] is neither a launch file in package [usb_cam] nor is [usb_cam] a launch file name
The traceback for the exception was written to the log file

解决方法：

tanjx@tanjx-GL553VW:~$ source ~/catkin_ws/devel/setup.bash

输入后再运行launch文件

这个launch文件运行时会报错

... logging to /home/tanjx/.ros/log/9302bc00-f708-11e8-81e5-d0577b77f434/roslaunch-tanjx-GL553VW-8077.log
Checking log directory for disk usage. This may take awhile.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://tanjx-GL553VW:33033/

SUMMARY
========

PARAMETERS
 * /image_view/autosize: True
 * /rosdistro: melodic
 * /rosversion: 1.14.3
 * /usb_cam/camera_frame_id: usb_cam
 * /usb_cam/image_height: 480
 * /usb_cam/image_width: 640
 * /usb_cam/io_method: mmap
 * /usb_cam/pixel_format: yuyv
 * /usb_cam/video_device: /dev/video1

NODES
  /
    image_view (image_view/image_view)
    usb_cam (usb_cam/usb_cam_node)

ROS_MASTER_URI=http://localhost:11311

process[usb_cam-1]: started with pid [8092]
process[image_view-2]: started with pid [8093]
[ INFO] [1543847705.122842479]: Using transport "raw"
[ INFO] [1543847705.139703367]: using default calibration URL
[ INFO] [1543847705.140399744]: camera calibration URL: file:///home/tanjx/.ros/camera_info/head_camera.yaml
[ INFO] [1543847705.140477468]: Unable to open camera calibration file [/home/tanjx/.ros/camera_info/head_camera.yaml]
[ WARN] [1543847705.140504075]: Camera calibration file /home/tanjx/.ros/camera_info/head_camera.yaml not found.
[ INFO] [1543847705.140525394]: Starting 'head_camera' (/dev/video1) at 640x480 via mmap (yuyv) at 30 FPS

(image_raw:8093): GLib-GObject-CRITICAL **: 22:35:05.148: g_object_unref: assertion 'G_IS_OBJECT (object)' failed

(image_raw:8093): GLib-GObject-CRITICAL **: 22:35:05.208: g_object_unref: assertion 'G_IS_OBJECT (object)' failed
[ WARN] [1543847705.838083656]: white_balance_temperature_auto: Input/output error
VIDIOC_S_CTRL: failed: Input/output error

[ WARN] [1543847705.848456329]: unknown control 'focus_auto'

Attempt to unlock mutex that was not locked
[image_view-2] process has died [pid 8093, exit code -6, cmd /opt/ros/melodic/lib/image_view/image_view image:=/usb_cam/image_raw __name:=image_view __log:=/home/tanjx/.ros/log/9302bc00-f708-11e8-81e5-d0577b77f434/image_view-2.log].
log file: /home/tanjx/.ros/log/9302bc00-f708-11e8-81e5-d0577b77f434/image_view-2*.log

我当时得到这个报错整个人都是懵的，然后我也不会修改，于是我在国内查，查不到解决方法，在国外查也没解决。就这样折腾了三天，期间还换了一次系统（就是它让我放弃了ubuntu 16.04 重装为 ubuntu 18.04），重装了三次ros，期间问过师兄，师兄也没解决，他也忙，所以我自己继续折腾，然后突然闹心的又打开了一个终端，运行了标定程序。。。。。。他就这样打开了～打开了～！！！所以着重强调这个报错不用管！

4.标定程序

rosrun camera_calibration cameracalibrator.py --size 8x6 --square 0.108 image:=/usb_cam/image_raw camera:=/usb_cam

8x6和0.108是官方给出的标定板的尺寸，请根据自己的修改比如我的是8x6和0.0216

为了得到一个好的标定结果，应该使得标定板尽量出现在摄像头视野的各个位置里：
如标定板出现在视野中的左边，右边，上边和下边，标定板既有倾斜的，也有水平的.所以多动一动～

界面中的

x：表示标定板在视野中的左右位置。

y：表示标定板在视野中的上下位置。

size：标定板在占视野的尺寸大小，也可以理解为标定板离摄像头的远近。

skew：标定板在视野中的倾斜位置。

执行后

不停地动直到右边的按钮亮起，点击CALIBRATE开始标定，过程大约1,2分钟

标定成功够右边三个按钮全亮，此时终端里会显示你的摄像机的各个参数

然后点击COMMIT保存数据，终端会显示

'Wrote calibration data to', '/tmp/calibrationdata.tar.gz')