AR projects use anchors to map digital content onto the real world, ensuring virtual elements stay fixed in place when viewed through a phone camera or device. These anchors can be tied to surfaces, such as floors or walls, allowing AR content to appear naturally within a space. 2D image targets, like posters or signs, provide reliable anchors for triggering interactive experiences. 3D object tracking enables AR to attach content to physical artefacts, though this is more challenging due to lighting and perspective changes. Curved image targets, like book spines or cylindrical columns, can work but require advanced tracking to compensate for distortion. Some AR systems also use spatial anchors, which map entire environments, enabling persistent AR content that stays in place even when the user moves around. These different anchoring methods ensure that digital overlays align accurately with the physical world, creating seamless interactive experiences.
What Makes a Good 2D Image Target?
The most reliable AR experiences are built around high-quality 2D image targets—flat images that an AR device can quickly recognise and track. But not all images work equally well.
Characteristics of an Effective 2D Target:
High contrast – The greater the difference between light and dark areas, the easier it is for AR software to detect unique features. Black-and-white designs, or images with clear tonal variation, work best.
Rich detail – Patterns, textures, and distinct shapes provide a wealth of reference points for AR tracking. A historical painting, for example, contains many intricate details that help the software maintain a lock on the target.
Non-repetitive elements – AR struggles with grids, tiled patterns, or repetitive motifs, as these can confuse the system by creating too many similar-looking areas.
Matte, non-reflective surfaces – Glossy paper or laminated prints can cause glare, making it difficult for the software to detect the image reliably under different lighting conditions.
Clear edges and defined shapes – Well-defined edges help the AR system differentiate the target from its background.
Examples of Good 2D Targets in Cultural Spaces:
Posters or signage with bold, detailed designs.
Historical paintings and illustrations with rich textures and colours.
Maps or old documents featuring intricate lettering and symbols.
Tapestries or textiles with high contrast and complex patterns.
What Makes a Bad 2D Image Target?
Not all images are suitable for AR tracking. Poor image targets can lead to unstable tracking, glitches, or complete failure to trigger AR content.
Examples of Problematic Image Targets:
Stained glass windows – These can be highly detailed, but their transparency, lighting variations, and reflections make them difficult for AR to track.
Far-away objects – If an image is mounted high up on a wall or ceiling, it becomes harder for visitors to scan it properly. The further away the image is, the more difficult it is for AR software to detect small details.
Eroded or damaged images – Stone carvings, faded murals, or weathered plaques with missing details and low contrast are challenging for AR to recognise. The software relies on clear, high-detail images with strong visual markers.
Overly simple images – A plain logo or basic shape without enough variation in texture or contrast won’t provide enough tracking points.
Tip: If a historical site has an image that doesn’t work well as a direct AR target, consider placing a well-printed reproduction nearby or using an alternative marker such as a QR code.
The Challenges of Using 3D Objects as Targets
While AR can track some 3D objects, the process is far more complex and less reliable than using 2D images. Many cultural and heritage institutions consider using artefacts, statues, or architectural features as AR triggers, but this comes with significant challenges.
Why 3D Object Tracking is Difficult:
Shape and symmetry issues – Objects with smooth or highly symmetrical surfaces (such as vases, columns, or spheres) lack distinctive visual markers, making them harder to track.
Lighting conditions – Shadows, reflections, and varying light sources can interfere with tracking. An object that looks one way in the morning light may appear completely different later in the day, causing AR software to struggle.
Viewing angles – Unlike flat images, 3D objects can be seen from multiple perspectives, which makes it harder for AR to maintain a stable track, especially if the user moves around.
Background interference – If an artefact is placed in front of a cluttered background or in an area with frequent visitor movement, the tracking may become unstable.
Because of these difficulties, using a 3D object as the sole AR target is sometimes unreliable. However, there is a simple workaround.
Using 2D Image Targets Adjacent to 3D Objects
To bypass the challenges of 3D object tracking, many AR experiences use a 2D target placed near a 3D object.
A printed image, plaque, or sign is placed close to the artefact. When visitors scan the image, it triggers AR content related to the nearby object.
Why This Works Better:
More reliable tracking – A well-designed 2D target is easier for AR software to detect and lock onto.
Consistent user experience – Visitors can scan the same spot every time, reducing errors caused by lighting or movement.
More storytelling opportunities – The 2D target can display text, illustrations, or extra details that complement the AR experience.
Examples in Cultural Spaces:
A printed plaque next to a statue that triggers a 3D animation of how the sculpture was originally created.
A museum label beside an ancient artefact that displays a video of experts explaining its history.
A floor-mounted marker near ruins that overlays a full digital reconstruction of the original structure.
Types of AR Content Available
Once an AR target is detected, it can display a wide range of interactive digital content:
Images – High-resolution photos, old maps, or artistic reconstructions.
Videos – Archival footage, historical documentaries, or expert narrations.
Text and annotations – Interactive labels, translations, or pop-up facts.
Animations – Moving illustrations or digital reconstructions of historical events.
3D models – Digital recreations of artefacts, missing architectural details, or interactive museum objects.
Final Thoughts
AR is an exciting way to engage audiences with cultural heritage, but choosing the right targets is crucial for a seamless experience.
Use high-contrast, detailed 2D images for reliable tracking
Avoid faded, reflective, or distant objects that interfere with AR recognition.
If a 3D object is the focus, use a 2D image nearby as a stable trigger.
By applying these principles, heritage sites can create immersive, interactive experiences that captivate visitors while ensuring a smooth and frustration-free AR experience.