Automatic correction method for panoramic multi-projector displays

DYNA (September 2013)

Abstract

In this paper we present an easy and novel method to calibrate a panoramic multi-projector display system. These kinds of displays have a wide range of applications in fields such as simulation, entertainment, marketing and data visualization.

Our correction method uses a commercial off-the-shelf camera that rotates around its vertical axis in order to cover the entire screen. Light structured patterns are projected on this screen in order to establish the transformation that relates the camera to each projector. As the camera is only transformed with a pure rotation different views of the camera can be related using panoramic photo stitching algorithms. These photographic techniques allow to establish a common reference frame for all the projectors where the necessary correction can be calculated easily. Once all the transformation relations between the camera, projectors and projection surface are calculated the partial images emitted by each projector can be corrected in order to calibrate the system geometrically. Also, the application of Bezier patches to model the projectors allows the use of an uncalibrated camera. Our main contribution is the application of panoramic photo stitching algorithms to multi-projector display correction in order to make the correction procedure easier compared to previous methods.

The validation of the described methodology is done presenting the case of a panoramic display composed of five projectors.

Optimized methods for multi-projector display correction publication

INTERNATIONAL JOURNAL ON INTERACTIVE DESIGN AND MANUFACTURING (April 2012)

Abstract

Multi-projector displays are commonly used for a wide range of applications such as virtual reality systems, simulators or data visualization where a high resolution image over a large projection surface is required. Such systems are cheap for the resolutions they can provide, can be configured to project images on almost any kind of screen shapes and are easily scalable, but in order to provide a seamless image with no photometric discontinuities they require a precise geometric and colour correction. In this paper, we propose a series of optimization techniques for large projection displays which make the adjustment procedure simpler and faster. Calibration method uses commercial off-the-shelf equipment such as a webcam and an intermediate performance graphics card. Multiple views are used if one camera image can’t cover the entire display with enough resolution. The effect of these optimizations in the calibration of a simulated display formed by 48 projectors are shown.

Tiled Projector Displays Correction for Dark Scenes in Railway Simulators

UKSim European Symposium on Computer Modeling and Simulation (November 2011)

Abstract

Tiled projector displays are a common choice for training simulators, where a high resolution output image is required. They are cheap for the resolution that they can reach and can be configured in many different ways. Nevertheless, such kinds of displays require geometric and color correction so that the composite image looks seamless. Display correction is an even bigger challenge when the projected images include dark scenes combined with brighter scenes. This is usually a problem for railway simulators when the train is positioned inside a tunnel and the black offset effect becomes noticeable. In this paper, a method for fast photometric and geometric correction of tiled display systems where dark and bright scenes are combined is presented. The image correction is carried out in two steps. First, geometric alignment and overlapping areas attenuation for brighter scenes is applied. Second, in the event of being inside a tunnel, the brightness of the scene is increased in certain areas using light sources in order to create the impression of darkness but minimizing the effect of the black offset.