Multi-projector System Research Articles

3D surface visualization of planetary data using Indian remote sensing datasets on a specialized multiprojector system

3D surface visualization of planetary data using Indian remote sensing datasets on a specialized multiprojector system

Calibration method of multi-projector display system with extra-large FOV and quantitative registration accuracy analysis.

The calibration of multi-projector display with extra-large field of view (FOV) and quantitative registration analysis for realizing perfect visual splicing is crucial and difficult. In this paper, we present a novel calibration method to realize the seamless splicing for a multi-projector display system with extra-large FOV. The display consists of 24 projectors, covering the range of 360 degrees in the longitude direction and 210 degrees in the latitude direction. A wide-angle camera fixed on a rotating optical system is used to scan the entire display scene and establish point-to-point correspondence between projector pixels and spatial points using the longitude and latitude information. Local longitude table and latitude table are established on the target of the wide-angle camera. A deterministic method is proposed to locate the North Pole of the display. The local tables corresponding to different camera views can be unified based on the image of the North Pole to form global longitude and latitude tables of arbitrary free-form surface. The mapping between the projector pixels and the camera pixels is established by inverse projection technique, and then each pixel of each projector can be appointed a pair of unique longitude and latitude values. A quantitative registration accuracy analysis method is proposed for multi-projector display system, in which, three-frequency temporal unwrapping method based on coded longitude and latitude values is applied to calculate the registration accuracy. Experiments prove that the registration error of the multi-projector system is less than 0.4 pixels.

Automatic geometry calibration for multi‐projector display systems with arbitrary continuous curved surfaces

A large-scale multi-projector display system offers high-resolution, high-brightness and immersive visualisation for realistic experience to end users. It has been demonstrated to be effective tackling the conflict between the increasing demands of super-resolution display and the resolution limitation of a single display system. However, there is still no standardisation method for curved-surface projection screen. In this study, we propose a novel approach for calibrating multi-projector display systems, which have curved surfaces. First, based on a detailed analysis on arbitrarily curved surfaces, we present a three-dimensional reconstruction algorithm based on Bezier surface models. Then, for fully utilising the projection area of each projector, we propose a novel curved-surface stitching algorithm to achieve geometry seamlessness of multi-projector display systems. Experimental results show that by constructing local Bessel models for the curved screen, the proposed method performs better than traditional approaches, i.e. the new method achieves geometric calibration with higher accuracy. The proposed method of modelling projection screen and the corresponding automatic geometric correction scheme effectively increase the utilisation ratio of the original projection area of each projector and improve the calibration accuracy of multi-projector system with continuous curved surface.

Adaptive stray-light compensation in dynamic multi-projection mapping

Projection-based mixed reality is an effective tool to create immersive visualizations on real-world objects. Its wide range of applications includes art installations, education, stage shows, and advertising. In this work, we enhance a multi-projector system for dynamic projection mapping by handling various physical stray-light effects: interreflection, projector black-level, and environmental light in real time for dynamic scenes. We show how all these effects can be efficiently simulated and accounted for at runtime, resulting in significantly improved projection mapping results. By adding a global optimization step, we can further increase the dynamic range of the projection.

Seam-Based Edge Blending for Multi-Projection Systems

Perceptual seamlessness of large-scale tiled displays is still a challenge. One way to avoid Bezel effects from contiguous displays is to blend superimposed parts of the image over the edges. This work proposes a new approach for edge blending. It is based on intensity edge blending adapted on the seam description of the image content. The main advantage of this method is to reduce visual artifacts thanks to context adaptation and smooth transitions. We evaluate the quality of the method with a perceptual experiment where it is compared with state-of-the-art methods. The new method shows most improvement in low frequency areas compared to the other techniques. This method can be inserted into any multi-projector system that already applies edge blending.

Multi-projector auto-calibration and placement optimization for non-planar surfaces

Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen’s manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

Real-time drawing technique for textured surface based on multi-projector system

With the development of the hardware performance of projectors and techniques on computer graphics,projections are used on more common surfaces so as to provide vivid and shocking visual effects.A new method that employed multi-projector system and interactive flat devices to modify the appearance of textured surface in real-time was introduced. On the basis of analyzing the color modeling of the system,an algorithm which recovered radiometric parameters and distributed the projection energy properly was presented. Efficient interactive-rendering pipelines were developed to insure that newly designed patterns could be projected on surface of objects without geometry and radiometric distortions. Experimental results show that the proposed method could improve the system accuracy of compensation while enlarging the system intensity range. Interaction,drawing and rendering modules of the system work synchronously to compensate the target appearances in real-time.

Analysis of a Scalable Multi-Projector System for Virtual Reality Environments

Virtual reality environments with multi-projector systems provide better visual quality, higher resolution and more brightness than traditional single-projector systems. Moreover, using multiple low-cost projectors is economically advantageous in comparison to an expensive high-end projector for equivalent visual performance. This article presents the research and development of a scalable multiprojection system that enables the construction of virtual reality systems with a large number of projectors and graphics computers, and that is capable of achieving a high resolution display. We demonstrate the viability of such system with the development of a camera-based multiprojector system library called FastFusion, which automatically calibrates casually aligned projectors to properly blend different projections. Our system software improves known algorithms in the literature for projector calibration and image blending. As a result, FastFusion improves system scalability and calibration reliability. In a detailed analysis of the visual performance of FastFusion in a CAVE system with three walls, eighteen projectors and nine computers, we achieved a satisfactory result for variance in geometric calibration and for graphics performance. Thus, our library is suitable for building complex projector systems and with retina resolution.

Combining digital image correlation and projected fringe techniques on a multi-camera multi-projector platform

This paper presents how a shape measurement system (SMS) based on projected fringes can be combined with a 2-D digital image correlation (DIC) technique to accurately measure surface profile and 3-D displacement fields at the same time. Unlike traditional 3-D DIC techniques, the proposed method can measure discontinuous surfaces as easily as smooth ones. The method can also be extended to a multi-camera multi-projector system, and thus complete 360° 3-D displacement fields can be obtained within a single global coordinate system. Details of the algorithm are presented together with experimental results.

重畳型マルチプロジェクションシステムによる流れの可視化の高解像度表示について

重畳型マルチプロジェクションシステムによる流れの可視化の高解像度表示について

Strategies for 3D video with wide fields-of-view

Real three-dimensional images make their full impact only if seen over a wide field-of-view, but those on present three-dimensional video displays rarely span more than 20°. The field-of-view of a multiprojector three-dimensional display can be expanded to 90° or more by a circularly symmetric field lens, and the dark zones typically present between the views of a multiprojector system can be eliminated without ghosting by using a pinhole projector equivalent arrangement and a precise diffuser. A planarised version of the optics has been demonstrated, and if combined with a waveguide screen and microdisplays may give an inexpensive three-dimensional display which has a large, flat screen and wide field-of-view.