Area Targets are a target type that can be used to track parts of your surroundings. It offers unique opportunities for augmenting any part of the environment that was included in the Area Target. In order to use Area Targets, special hardware is required for scanning the chosen environment according to each of the device types’ guidelines.
This article informs you of the practices for choosing, preparing, and capturing an environment. The article is divided into sections that describe practices for supported scanning equipment such as the Matterport™ Camera Pro2 3D and for handheld scanning devices with ARKit and LiDAR. For a list of devices capable of creating scans suitable for Area Targets, please see the main page Area Targets.
- We classify scanning equipment as professional high-performance devices capable of covering large areas that returns a highly defined 3D model, mesh, and texture.
- We consider handheld scanning devices to only accommodate smaller spaces. A handheld scanning device will produce a 3D model well suited for tracking and authoring, but you should not expect the same quality and detail to that from one of the supported scanner vendors. In addition, the scanning duration will most likely be limited to a short scanning duration; as it is the case with the Vuforia Area Target Creator App that concludes if the 5-minute mark is reached in order to avoid running out of available memory on the device.
The space should be static; objects that are included in the scan should be fixed and unlikely to be moved. In environments, such as exhibition booths or office spaces with many movable elements or persons, verify that enough portions of the surroundings – such as wall decorations, ceiling-based installations, floor covering, stable furniture or similar are always visible during the intended augmentation scenarios.
Factory floors, whole apartments, museums, and large indoor spaces are all suitable candidates to scan and produce an Area Target with a professional scanning setup. Choosing an environment to scan with a professional scanner should be based on these specifications:
- Indoor spaces up to 1.000 m² or 10,000 sq ft with consistent artificial lighting. For even larger environments, divide the space into multiple separate scans.
More device specific information can be found in the Area Target Scanning Guide using Matterport.
Exhibition booths, small cafés, and a room of an apartment are ideal scenes to scan using a handheld device. Choosing an environment to scan with a handheld scanner should be based on these specifications:
- Indoor spaces up to 50 m2 or 500 sq ft with consistent artificial lighting.
More information can be found in the Vuforia Area Target Creator App article.
Scanning an Environment
Preparing the Space
When you have selected an environment to scan that upholds the abovementioned criteria, it is advisable to prepare as much as possible before starting the scanning process. Preparation includes charging the equipment and overlooking the space that will be captured.
- Inspect the space, tidy up the environment, and remove items that you do not wish to be included in the scan.
- Minimize incoming sunlight from windows by closing the curtains or blinds. At the same time, ensure enough lighting is provided, by e.g. switching on lamps and lights, providing a typical lighting scenario.
- Close the doors to rooms and spaces that are not to be included.
Planning your path and scan positions
Before starting to scan, you should follow a normal walking path through the space. As an option you can mark the scanning positions with tape in a grid like pattern 1.5 to 2.5 m (5 to 8 ft) apart and 0.6 m (2ft) from walls, doors and objects. This will ensure a clean line of sight and capturing the entire space without distortions, slices, and warps.
- Mark positions at natural points of interest within the space (i.e. at a workstation, desk, or machinery).
- Avoid marking scanning positions in corners, too close to walls, and in the doorways.
- In cases where you move around a corner, mark down also at the corner’s edge.
- For doors, scan before and after entering a new room while maintaining the above-mentioned distance.
- Make additional scans where a visitor or user would look for more information.
Planning your path and scanning motions
With smaller rooms it is still advisable to plan a path through the room. The distance to surfaces and objects should be scanned at a distance between 0.5 m (2 ft) to 2 m (6.5 ft). Scan the area fronto-parallel, which means only scanning surfaces and objects directly in front of you.
- Prepare a path along the walls or boundaries that will allow you to scan all the major features in the room. Avoid loop closures (the scanning path ends where you began) as it introduces drift in the reconstruction. Therefore, choose a start and end position near each other that also prevents you from rescanning your start position.
- The path should be laid out so, if possible, you only scan an area once.
- Tables and flat structures such as screens do not require to be scanned from both sides.
- Similarly, scanning beneath, behind or around objects that are considered inaccessible, and unlikely for users to approach, is better to exclude than to include.
- Complex objects such as vegetation are difficult to capture in detail.
- Transparent or reflective surfaces is captured poorly by handheld scanners and it is recommended to avoid scanning them or covering them up.
- In addition, including bare walls, floors, and ceilings in the scan will have little effect on the area’s tracking experience.
Try to avoid scanning while there is activity in the space. Similarly, you should also stay clear of being present in the scans.
If possible, monitor the scanning progress via a provided application or other software to ensure correct alignment of the new parts in-between scans. Correct failed scans by re-scanning on the position or move closer to the prior scan for achieving a better result that is compatible with your model.
Depending on the device there may be special directions on how to best achieve a successful scan. We have found that moving at a steady speed and scanning in an up-and-downwards continual motion provides good results. The Vuforia Area Target Creator app overlays a live mesh that offers a helpful indication of the captured parts of the environment.
- Scan fronto-parallel to the surfaces (walls and other facades) and scan an area only once.
- Scan in vertical motions (from down and up).
Illustration of a fronto-parallel and continuous scanning motion
- Avoid too fast motions and rotations, it is likely to break the scanning process or result in a warped reconstruction.
- Maintain a scanning distance of 0.5 - 2 m (1.5 – 6.5 ft).
- Avoid scanning an area that you are approaching from afar (more than 2 meters), and instead, enter that area within the recommended range of distance.
Completing the Scan
Depending on the device and/or application that was used to scan the area, there may be some specific steps to review, improve and complete the scan. In general, the new digital model should be reviewed for any missing parts or inconsistencies.
- Any missing parts should be reconciled with additional scans. If a tool is provided along with the scanning device to edit the digital model in terms of i.e. removing unwanted parts or improving it by marking windows, mirrors etc., do so during or after the scanning is complete.
As an example, Matterport™ provides the Matterport™ Capture iOS application that allows you to review the model in a dollhouse view for any inconsistencies and add extra scans to fill in those blank spaces to gain a complete scan. The Capture App also offers tools to remove any parts that you do not wish to have in the final mesh. For information on the Matterport™ Capture App, please refer to Area Targets Scanning Guide or Best Practices from Matterport™.
Assisting Area Target Tracking
Rooms and environments with more unique features and objects tend to do better in tracking and re-localization. In environments containing repeated structure and/or multiple instances of the same objects, tracking locations may be mistaken for one another or not be recognized. To accommodate spaces with less features or repetitions, we recommend adding additional features such as prominent objects or markers that can aid the tracking, or you may use the location prior for (first-time) localization. See the Area Target API Overview for more information.
Reflective and transparent surfaces are commonly difficult to capture. If the environment possesses glass walls, glass tables, a very large surface is a glossy metal with reflections, consider covering such surfaces or abstain from scanning them.