# Recording data with the rc_visard¶

This tutorial shows how to record sample data sets with the rc_visard.

Fig. 9 Web GUI Camera tab with snapshot button

For downloading the left and right camera images of the current scene, go to the camera page in the rc_visard’s Web GUI and click on the “Download snapshot” camera button below the images (see Fig. 9). This will create an archive containing the left and right camera images, as well as the rc_visard’s current parameters, which can be downloaded.

For downloading depth data, go to the depth image page in the rc_visard’s Web GUI and click on the “Download Snapshot” camera button below the images. This will create an archive containing the left and right camera images, the disparity, error and confidence images, as well as the current point cloud as a ply file, and the rc_visard’s current parameters.

## Recording image sequences¶

Note

The following instructions are only applicably if you want to download image sequences (image streams) from the rc_visard. For recording single snapshots, follow the approach above.

### Before we start¶

Before going through this tutorial, the following prerequisites should be met.

The rc_visard is up and running:

1. The rc_visard is running and connected properly to the host. One can verify that with our discovery tool.
2. One should know the serial number or user defined name of the rc_visard. The serial number is of the format 029xxxxx. It will be referred to as rc_visard_id in the remainder of this tutorial.

For Ubuntu, we provide ready-to-use Debian packages.

For Windows, all required software is bundled with the recording scripts, so no download is necessary.

Optional software for viewing the recorded images can be installed:

For Linux, it is easiest to download the source code and build it by entering the main directory and typing:

mkdir build
cd build
cmake ..
make
sudo make install


Images can be viewed using the viewer sv. Disparity images, i.e. with the suffix .pfm can be viewed in 3D by pressing ‘p’ or calling plyv with the disparity image as argument. Both tools show a help page with all key codes by pressing ‘h’.

For Windows, pre-compiled software is available in a ZIP archive. The archive contains a self-installing executable.

After installation, images can be viewed by double clicking on them in the explorer. Disparity images, i.e. with the suffix .pfm can be viewed in 3D by pressing ‘p’. Both tools show a help page with all key codes by pressing ‘h’.

The network configuration is optimized:

Enable “Jumbo frames” by setting the MTU to 9000.

Temporarily

Enter the following command in the terminal.

ifconfig <interface> mtu 9000


Persistently

1. Open the network manager
2. Select interface and edit settings
3. On “Ethernet” tab, change MTU to 9000
1. Open “Network Connections”
2. Right-click on the network interface
3. Choose “Properties”
4. Click “Configure”
5. On the “Advanced” tab, choose “Jumbo Packet”
6. Select “9014 Bytes”

### Recording data¶

We provide scripts for Linux and Windows to record data in our rc_visard_offboard_record GitHub repository.

The script offers two modes: An interactive mode that is started if the script is launched via a double-click or called without any arguments from a terminal/command line window. In that mode, the user is asked by the script for the rc_visard_id. In standard mode, in contrast, the rc_visard_id is passed to the script as command line argument, optionally next to other arguments.

Each time, the script runs, it creates a new folder in the working directory (i.e. the place the script was started in) and writes all data to that folder. The folder’s name is of the format rc-visard_<SN>_<T>, where <SN> is replaced by the rc_visard_id and <T> by the current time. The images are stored in PGM or PPM format, which are supported by many image viewers. All other files are stored as text.

Caution

On Windows, proper configuration of the firewall is important. On the first run of the script, the user will be asked whether the rc_genicam_api and rc_dynamics_api tools should be allowed to access the network. This needs to be allowed, otherwise the script will not work properly. In case of problems with data recording, temporarily disabling the firewall can help to pinpoint the source of the problem. It may be necessary to manually whitelist gc_info.exe, gc_config.exe and gc_stream.exe that are located in the folder rc_genicam_api-*, and rcdynamics_stream.exe that can be found in the folder rc_dynamics_api-*.

#### Interactive mode¶

Start the script via double-click. The script asks for the rc_visard_id, i.e. the serial number (which is of the format 029xxxxx) or user defined name. By entering L, all available rc_visard devices are listed. Interactive mode does not allow changing of script parameters other than the rc_visard_id. If that is required, the standard mode should be chosen, as it offers more flexibility.

#### Standard mode¶

In standard mode, the script is called from a terminal/command line window.

The basic usage is as follows:

1. Open a terminal.

2. Change to the script folder.

3. Launch the rc_visard_record.sh:

./rc_visard_record.sh [options] <rc_visard_id>

1. Open a terminal.

2. Change to the script folder.

3. Launch the rc_visard_record.bat:

rc_visard_record.bat [options] <rc_visard_id>


The script offers optional arguments, which can be listed with the -h flag:

./rc_visard_record.sh -h

rc_visard_record.bat -h


By default, the script will run until it is stopped with Enter and record images from the left camera, disparity images, confidence images and error images.

This behavior can be changed by passing different arguments to the script. For example, to record only the left camera images and stop after 10 images, the following command can be used:

./rc_visard_record.sh --number=10 --left=true --right=false --disparity=false --confidence=false --error=false <rc_visard_id>

rc_visard_record.bat -n 10 -left true -right false -disparity false -confidence false -error false <rc_visard_id>


The cam-params argument allows to also record the current camera parameters including the camera calibration. It will write the parameters to the given file, below called params.txt.

./rc_visard_record.sh --cam-params=params.txt <rc_visard_id>

rc_visard_record.bat -cam-params params.txt <rc_visard_id>


The script also supports recording of the SLAM trajectory, which can be enabled with the slam argument. The script will automatically start and stop SLAM, and eventually write the trajectory to the given file (trajectory.json in the example). The trajectory is written when image grabbing is finished, which is either when the user presses Enter or enough data sets are recorded according to the number argument.

./rc_visard_record.sh --slam=trajectory.json <rc_visard_id>

rc_visard_record.bat -slam trajectory.json <rc_visard_id>


### Troubleshooting¶

rc_genicam_api is not installed properly.

rc_dynamics_api is not installed properly.

The script writes “Cannot find device: 01234567” or “Device 01234567 not found”

The script could not find the rc_visard with the given serial number. Are serial number and network configuration correct?

The script writes “storeBuffer(): Received incomplete buffer”

The network configuration may be slow or not optimized properly. Is the rc_visard connected via a 1 GBit/s wired ethernet connection? Please follow network optimization. Try to connect the rc_visard to the host directly.

The script writes “Device::open() failed”

The rc_visard may have not booted completely yet, or another client may already be connected to the rc_visard.

The script writes “Cannot grab images”

The network may not be configured properly. On Windows, the firewall may block the network connection. Temporarily disabling the firewall can help to pinpoint the source of the problem. Try to connect the rc_visard to the host directly.