Welcome to NUWA-HP60C Depth Camera repository

16. Hough Line Detection

16.1、Use

Source code launch file path: /opt/ros/noetic/share/opencv_apps/launch

Step 1: Start the camera

roslaunch ascam_visual opencv_apps.launch img_flip:=false

• img_flip parameter: whether the image needs to be flipped horizontally, the default is false.

The [usb_cam-test.launch] file opens the [web_video_server] node by default, and you can directly use the [IP:8080] web page to view the image in real time.

Step 2: Start the Hough line detection function of Opencv_apps

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roslaunch opencv_apps hough_lines.launch # Hough line detection

Each function case will have a parameter [debug_view], Boolean type, whether to use Opencv to display the image, the default is displayed.

If you don't need to display, set it to [False], for example

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roslaunch opencv_apps hough_lines.launch debug_view:=False

However, after starting in this way, some cases may not be displayed in other ways, because in the source code, some [debug_view] is set to [False], which will turn off image processing.

16.2, Display method

• rqt_image_view

Enter the following command and select the corresponding topic

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rqt_image_view

• opencv

The system displays by default, and no processing is required.

• Web viewing

(Under the same LAN) Enter IP+port in the browser, for example:

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192.168.2.116:8080

For specific IP, use your current virtual machine IP.

16.3, Effect display

The lower the threshold, the more lines, and the easier it is for the screen to get stuck.