An Efficient, Platform-Independent Map Rendering Framework for Mobile Augmented Reality

Abstract

With the extensive application of big spatial data and the emergence of spatial computing, augmented reality (AR) map rendering has attracted significant attention. A common issue in existing solutions is that AR-GIS systems rely on different platform-specific graphics libraries on different operating systems, and rendering implementations can vary across various platforms. This causes performance degradation and rendering styles that are not consistent across environments. However, high-performance rendering consistency across devices is critical in AR-GIS, especially for edge collaborative computing. In this paper, we present a high-performance, platform-independent AR-GIS rendering engine; the augmented reality universal graphics library (AUGL) engine. A unified cross-platform interface is proposed to preserve AR-GIS rendering style consistency across platforms. High-performance AR-GIS map symbol drawing models are defined and implemented based on a unified algorithm interface. We also develop a pre-caching strategy, optimized spatial-index querying, and a GPU-accelerated vector drawing algorithm that minimizes IO latency throughout the rendering process. Comparisons to existing AR-GIS visualization engines indicate that the performance of the AUGL engine is two times higher than that of the AR-GIS rendering engine on the Android, iOS, and Vuforia platforms. The drawing efficiency for vector polygons is improved significantly. The rendering performance is more than three times better than the average performances of existing Android and iOS systems.

An Accurate and Efficient Quaternion-Based Visualization Approach to 2D/3D Vector Data for the Mobile Augmented Reality Map

“…The quaternion pose of the AR spatial object is constantly updated synchronously when the real-time motion of MAR devices changes. Each render subthreads' bitmaps are merged to render at each updated position, and the merged entire bitmaps are saved and cropped to a larger size than the full screen [10]. The AR spatial object then notifies the main screen to refresh the cropped vector map and display it on the user screen of MAR devices.…”

“…where E denotes a 3 × 3 identity matrix. After acquiring the rotation matrix of the corresponding polygon object, the quaternion information of the polygon object can be obtained through the Equation (10).…”

“…1 + r 11 + r 22 + r 33 (10) After constructing the quaternion of the object, the main quaternion operations can be performed such as interpolation, conjugation, multiplication and inverse. The operation result is converted into a plane object in GIS.…”

“…Vector map visualization is one of the fundamental components of GIS, which plays an important role in AR-GIS [10]. In many MAR-related applications including ATs and AMs, vector visualization can enhance the presentation of the position and relationship of spatial objects, interactively annotate the objects in the physical space, and intuitively prompt the users to interact and form spatial cognition by overlapping the digital information on the physical world [11].…”

“…The main reason is that the spatial relationships in AR involve complex spatial semantics and specific 3D rendering issues. Different from traditional 2D/3D GIS, AR-GIS needs to determine the correct relationship between real and digital space [45], digital elements placement [25,46] including occlusion [47,48] and avoidance [10]. These tasks are crucial in AR-GIS because they are responsible of the spatial semantic constraints between the digital entities and the real environments.…”