Precautions

This chapter summarizes the key points to watch during scan startup, scanning, control point mode, RTK mode, colorization mode, and accuracy verification.

Scan Startup Stage (Device Initialization)

Startup Requirements

Device placement and stability

• Place the device on flat ground for static startup, avoiding movement and keeping it steady.
• You may steady the device gently during startup; make sure there are no people or obstructions in front of the LiDAR.

Initialization wait

• After the point cloud appears on the phone screen, keep the device still for at least 10 seconds.
• If using LixelGO 1.1.0 or above, pick up the device only after the app indicates "Initialization successful".

Picking up the device

• Pick up the device slowly, avoiding abrupt movements, and begin normal capture.

Initialization Environment Requirements

Operator position

• Keep an appropriate distance from the device and avoid blocking the LiDAR.

Environment selection

• Recommended: feature-rich areas.
• Avoid: feature-poor environments such as open plains, refractive environments such as large glass surfaces, and areas with many moving objects.

Scanning Precautions

Movement Requirements

Avoid the following actions:

• Turning your body sharply and quickly.
• Sudden stops.
• Fast, large device swings and shakes.

Walking Speed Control

• Normal scenes: keep walking speed below 1 m/s.
• Special scenes (feature-poor areas, narrow spaces, corners): slow down further.

Device Tilt Angle Limits

• Normal scanning: device tilt must not exceed 15°.
• Special cases (scanning the full ground in narrow areas, or scanning ground targets): may briefly exceed 15°, but not 30°.

Avoid Obstruction

Avoid the following for extended periods:

• Large objects obstructing within 1 m of the LiDAR's field of view.
• Obstruction covering more than 50% of the LiDAR's field of view.

Scan Distance Requirements

• General: keep at least 0.5 m from the scan target whenever possible.
• Important ground data: scan at a closer distance when possible, holding the scanner at the center of your body and avoiding getting too close to the ground.

Outdoor Scene Precautions

Applies to: roads, streets, and other dynamic scenes with heavy foot or vehicle traffic.

Requirements

• Avoid pointing the LiDAR at moving objects.
• If one side has many moving objects, point the LiDAR at the other side.
• Avoid having too many moving-object features in the LiDAR's field of view.

Multi-room / Multi-floor Indoor Scanning

Preparation

• Open all doors that need to be scanned in advance.

Passing through doors

1. Scan slowly and pause sideways at the doorway for a while.
2. Ensure you can scan features on both sides of the doorway at the same time.

If a door is not open

1. Turn around slowly before approaching the door.
2. Face the device away from the door.
3. Open the door with your back.
4. Enter slowly.

Control Point Mode

1. When setting down the device to mark a point, avoid heavy impact with the ground that causes vibration; pick the device up slowly and steadily afterward, as abrupt movements affect accuracy.
2. Mark the control point first; after LixelGO confirms it was added, pick up the device and walk around the control point 1–2 times or pause for a while to capture a more complete point cloud around it.
3. If you want to end the project recording after marking a control point, wait at least 15 seconds before ending.
4. To ensure post-processing accuracy, keep control point spacing under 50 m between points, evenly distributed across the survey area.

RTK Mode

1. The RTK module can only be used where there is an RTK signal; it cannot be used indoors without a signal.
2. Mind your holding posture; normally keep the device tilt within 10°.
3. Minimum requirement (absolute coordinate conversion possible, but with reduced accuracy): scan area > 10 m and more than 20 valid RTK data points (valid data means more than 20 valid points shown in LixelStudio).
4. For accuracy verification, the capture route must be ≥ 100 m and not a straight line.
5. To ensure post-processing accuracy, keep the continuous unfixed RTK distance < 50 m.

Colorization Mode

1. To ensure colorization results, capture for at least 3 minutes and keep moving during capture; do not keep the scanner still in one place.
2. Point cloud colorization depends on the surrounding environment and ambient light:
   • When colorization is needed in dark environments, add lighting to ensure even brightness.
   • Avoid overexposure or excessive light during scanning.
3. Mind how you hold the scanner during capture; avoid blocking the body cameras or having objects on one or both sides of the camera for long periods, to prevent affecting colorization.

Accuracy Verification

For accuracy verification, scan around the target points where markers are attached, or pause at the markers, to capture a more complete target point cloud. This improves the success rate of automatic target point extraction during later accuracy verification.