ZEB GeoSLAM Horizon 3D Mobile Scanner User Guide

ZEB GeoSLAM Horizon 3D Mobile Scanner

 Introduction

To successfully integrate the ZEB Vision camera and the ZEB Horizon scanner, there are two calibrations that must be performed:

1. Internal camera calibration, to describe the internal characteristics of the camera.
   •  This is carried out by GeoSLAM before the camera is delivered.
2. External system calibration, to determine the differences in the rotations of the camera’s rotational axes and the rotational axes of the laser scanner.

•  If a complete ZEB Horizon / ZEB Vision system is purchased, this calibration will be carried out by GeoSLAM before the system is delivered.
•  If the ZEB Vision is ordered separately, end-users must collect a calibration dataset to be sent to GeoSLAM for evaluation. GeoSLAM will create a unique calibration file for the specific camera / scanner combination that will be sent to the end-user.

Once a successful system calibration has been achieved there is no specific requirement for further system calibrations to be carried out unless:

1.  The ZEB Vision is detached from the ZEB Horizon scanner.
2. The user observes an offset between the scan data and imagery in the Connect Viewer, or processing produces poor colourisation of the laser data. This may occur if the system has received an impact.

 Hardware Checklist

For instructions on how to attach the ZEB Vision onto your ZEB Horizon, please consult the ZEB Vision Hardware User Guide.

• ZEB Horizon.
• ZEB Vision camera.
• Backpack (optional).
• Fixtures.
• ZEB Vision hard case.
• Main cable.
• Laptop.
• Ethernet download cable.
• PAG battery.
• USB stick.

Applicable Software

It is recommended that users confirm that the following control software is installed:
ZEB Horizon

• SHB firmware version 2.2.0

ZEB Vision

• ZEB Vision firmware version 2.1.0

These can be downloaded from GeoSLAM website  (https://geoslam.com/getting- started-zeb-vision/).

 Site Selection

Fundamental to the processing of the system calibration dataset, is the identification of features in both the laser data (typically in the intensity field), and the imagery. Therefore, site selection where the system calibration data is acquired needs careful consideration. To maximize the likelihood of calculating the most accurate system calibration, the following factors must be observed for the collection of the system calibration data:

1. The calibration must be carried out in an open, outdoor environment .Calibration site.
2. Calibration data should not be acquired indoors.
3.  There should be at least three easily identifiable features on the ground, e.g., white or yellow paint markings on asphalt, or corners of paving slabs.
4. There should be at least three easily identifiable features at height, e.g., lampposts, road signs, and corners of buildings.
5.  Space for at least five metres of clearance on either side of the operator.
6. Maximum distance to the features ~ 20m.
7. Total capture time is essentially defined by the amount of identifiable features in the capture, but in general should be relatively short (~ 5 minutes maximum).

The area shown in Figure 1, adequately covers the requirements for a successful calibration, containing numerous white paint markings, lampposts and corners of buildings. Plus the direction of capture ensures that features are always captured on both sides of the operator.

Data Capture

Before conducting the capture, the following should be considered:

• Ideally, the calibration will be carried out using the ZEB Backpack.
•  If a ZEB Backpack is not available, the calibration can be carried out using ZEB Horizon mounted on a standard reference plate.
•  As with any capture using the ZEB Vision, the operator should walk at a slower than normal walking speed. This will increase point density in the laser data and reduce the risk of blurred images.
•  The operator should keep the system as steady as possible during the capture, avoiding any sudden / sharp movements that will result in blurred images and errors in the point cloud.
• There is no requirement to specifically point the camera or scanner at a particular feature.

Before conducting the capture, make sure that the ZEB Vision camera is firmly attached to the ZEB Horizon by ensuring that:

•  the 4 mounting screws are secure and have been tightened with equal torque.
• the ZEB Vision camera is mounted flush to the rear plate of the ZEB Horizon by removing the four rubber dampers from the back of the scanner.
• the v-mount is secured to the camera assembly. If the v-mount is loose, the system may rotate on the v-dock during capture.

Backpack Capture

1.  Attach the system (ZEB Horizon and ZEB Vision) to the backpack using the v-mount system.
2.  Attach the data logger to the backpack using the v-mount system.
3. Connect the interface cables between the ZEB Horizon and data logger.
4. Set up the backpack on flat ground. Remember that this is a SLAM system so needs to be deployed in a feature-rich environment (preferably facing a feature such as a car or building corner, ~5-10m from the object.
5.  Turn on ZEB Horizon by pressing the power button.
6. Wait a few minutes until Status LEDs go red.
7. The ZEB Vision will power on at the same time as the ZEB Horizon, as indicated by the Green LED on the back of the camera.
8.  Start ZEB Horizon initialization (as per the ZEB Horizon User Guide) by pressing the Function button or the button on top of the ZEB Horizon scanner head.
9.  Wait until LEDs go green, and the scanner starts rotating automatically.
10. The ZEB Vision will begin capturing data automatically as indicated by the flashing Green LED on the back of the camera.
11.  Wait around 10 seconds, recording stationary ZEB Horizon data.
12. Take the backpack from the ground and put it on your shoulders (use the straps to tighten the fit – it should be a tight fit).
13. Commence the capture (remembering SLAM requirements and scanning with loop closure). Read the Best Practice Guide for more information.
14. Return to the start location.
15. Remove the backpack and place the backpack on the ground.
16. Once stationary on the ground, stop the scanner – long press on the Function button or on the top scanner head button.
17.  Copy the scan data from the ZEB Horizon as per ZEB Horizon User Guide.
18.  Copy the image data, including the camera calibration file, from the ZEB Vision (see Data Download section).

Handheld Capture

1.  Set up ZEB Horizon on flat ground. Remember that this is a SLAM system so needs to be deployed in a feature-rich environment (preferably facing a feature such as a car or building corner, ~5-10m from the object.
2. Turn on ZEB Horizon by pressing the power button.
3.  Wait a few minutes until Status LEDs on the ZEB Horizon go red.
4. The ZEB Vision will power on at the same time as the ZEB Horizon, as indicated by the Green LED on the back of the camera.
5. Start ZEB Horizon initialization (as per the ZEB Horizon User Guide) by pressing the Function button on the data logger or the button on top of the ZEB Horizon scanner head.
6.  Wait until LEDs go green, and the scanner starts rotating automatically.
7.  The ZEB Vision will begin capturing data automatically.
8. Wait around 10 seconds, recording stationary ZEB Horizon data.
9. Pick the scanner and datalogger up and begin walking.
10. Commence the capture (remembering SLAM requirements and scanning with loop closure). Read the Best Practice Guide for more information.
11. Return to the start location.
12. Place the scanner back in the same position as the operator started using the reference base.
13. Once stationary on the ground, stop the scanner – long press on the Function button or on the top scanner head button.
14.  Copy the scan data from the ZEB Horizon as per ZEB Horizon User Guide.
15.  Copy the image data, including the camera calibration file, from the ZEB Vision (see Data Download section).

• When capturing, walk at a slower than normal walking speed. This will increase point density and reduce motion blur in the images.
• Ensure that the system is kept steady and avoid sudden movements of the camera at all time, especially when using the system in handheld mode.

Data Download

ZEB Horizon
To download the raw scan data:

1. Power on the ZEB Horizon datalogger if not already powered on.
2. Connect the supplied USB storage device to the USB socket on the datalogger front panel. Data download will automatically start.

•  The AUX LED light will light green whilst the data is transferring to the storage device.
•  The USB storage device must not be removed when the AUX LED is lit green. After a few seconds (dependent on the size of the data files to be transferred) the AUX LED will turn off.
•  All data that has not previously been transferred will be transferred and the USB storage device can be removed.

The following USB storage device file formats are supported, exFAT, FAT32 and NTFS. Downloading data is an automatic process whereby only data that has not previously been downloaded will be transferred.
ZEB Vision
Data from the ZEB Vision is stored on the internal data drive in the camera. Each capture is stored in a separate project folder, e.g., Project_1, Project_2 etc. Images from the front and rear lens are stored individually, in JPG format. The file naming convention is:

•  nnn_F_xxxxxx.jpg -> Front lens.
•  nnn_R_xxxxxx.jpg -> Rear lens.

Where:

•  nnn: image number.
• F, R -> lens -> image from either Front or Rear lens.
• xxxxxx: internal camera timestamp.

A copy of the camera calibration file (camera_cal.json) is stored on the camera. When a new capture is started, a copy of the calibration file will automatically be copied into the project folder.

• It is essential that a copy of the camera calibration file (camera_cal.json) is in the same directory as the images.

Windows File Explorer
To download data from the camera:

1.  With the ZEB Vision connected to the ZEB Horizon datalogger, power on the datalogger if not already powered on.
2. Connect the camera directly to a PC using the supplied ethernet cable.
3. Open -> Windows File Explorer.
4. Input -> ftp://169.254.0.206 into the address bar .Accessing the camera folders using Windows File Explorer.
5.  Select -> Copy -> latest project folder to the folder on the local PC where the ZEB Horizon data has been downloaded.

GeoSLAM Datalogger Control Tool

From Version 3.3.0 of the GeoSLAM Datalogger Control Tool, users can simply interact with the ZEB Vision camera, including applying firmware changes, uploading calibration files and downloading images. To download data from the camera:

1. With the ZEB Vision connected to the ZEB Horizon datalogger, power on the datalogger if not already powered on.
2.  Connect the camera directly to a PC using the supplied ethernet cable.
3.  Open -> GeoSLAM Datalogger Control Tool.
4.  Select -> Remote -> Connect.
5. Select -> ZEB Vision, at the Control Selection pop-up.
6. Input -> IP Address -> 169.254.0.206 into the dialog.
7.  Select -> OK, to continue.
8. Select -> Local -> Browse,
   •  Browse to a directory to copy the data from the camera.
   •  Select -> Ok, to continue.
9.  Select -> Remote -> user defined directory, e.g. Project_2 Copy data from the camera using GeoSLAM Datalogger Control Tool.

• Right-Click -> Copy.
•  Select -> OK, at the pop-up to confirm the action.
• Select -> OK, at the pop-up to confirm the successful action.

To delete data from the camera:

1.  With the ZEB Vision connected to the ZEB Horizon datalogger, power on the datalogger if not already powered on.
2. Connect the camera directly to a PC using the supplied ethernet cable.
3.  Open -> GeoSLAM Datalogger Control Tool.
4.  Select -> Remote -> Connect.
5. Select -> ZEB Vision, at the Control Selection pop-up.
6.  Input -> IP Address -> 169.254.0.206 into the dialog.
7. Select -> OK, to continue.
8. Select -> Local -> Browse,
   •  Browse to a directory to copy the data from the camera.
   • Select -> Ok, to continue.
9. . Select -> Remote -> user defined directory, e.g. Project_2 . Delete data from the camera using GeoSLAM Datalogger Control Tool.

•  Right-Click -> Delete.
• Select -> OK, at the pop-up to confirm the action.
• Select -> OK, at the pop-up to confirm the successful action.

Alternatively, data can be browsed using any FTP file browser.

 Send Data

Once data has been collected and downloaded, this should be sent to support@geoslam.com.

• Please remember to include the serial number of your ZEB Vision with your email. This can be found on the rear of the camera.
• Please also include a copy of the ZEB Vision camera calibration file (camera_cal.json) that was supplied with the camera.

Calibration File

Once GeoSLAM has received and evaluated the data, the user will shortly receive an updated camera calibration file. This file must be uploaded to the camera to ensure that for every subsequent capture where ZEB Vision data is acquired, a copy of the calibration file will be included in the images folder, otherwise, images cannot be processed.
Processing data from the ZEB Vision requires GeoSLAM Connect version 2.1.1 and later. Please see Appendix C of the GeoSLAM Connect Software Guide for more information on how to process and view your ZEB Vision data.
Uploading the Calibration File
From Version 3.3.0 of the GeoSLAM Datalogger Control Tool, users can simply interact with the ZEB Vision camera, including applying firmware changes, uploading calibration files and downloading images.
To update the calibration file on the camera:

1.  With the ZEB Vision connected to the ZEB Horizon datalogger, power on the datalogger if not already powered on.
2. Connect the camera directly to a PC using the supplied ethernet cable.
3.  Open -> GeoSLAM Datalogger Control Tool.
4. Select -> Remote -> Connect.
5.  Select -> ZEB Vision, at the Control Selection pop-up.
6.  Input -> IP Address -> 169.254.0.206 into the dialog.
7. Select -> OK, to continue.
8. Select -> Settings -> Upload Calibration.
   • Browse -> user defined location of the calibration file (camera_cal.json)
   • Select -> OK, to continue.
   • Select -> OK, at the confirmation prompt to continue.
9. Power cycle the system.

References

• Getting Started: GeoSLAM ZEB Discovery

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