How to align multiple projectors?
Aligning multiple projectors can be a time-consuming task, whether it's an AV or entertainment event, a permanent exhibit in a museum, or a flight, ship, or vehicle simulator. Seamless integration from one projector channel to the next is essential.
Things get complicated when spherical or dome-shaped screens are involved, or when they are designed as 3D objects. Time and precision are critical factors in this process. Achieving accuracy often requires a significant investment of time, and in the event of a technology failure or operational change, the entire projector alignment process may have to be started from scratch.
The article describes the fundamental process of a camera-based calibration system, along with the software that can significantly aid in the process. While it is possible to perform the calibration manually, considering today's hourly rates, making it beneficial to explore suitable software tools. Moreover, in the realm of professional simulation setups, relying on such software solutions has become indispensable due to the high demands for accuracy and availability.
Blending, or edge blending, refers to the process of overlaying one projected image onto another at the edges, resulting in a seamless merge of multiple projector images into one cohesive display. This technique also involves adjusting the brightness to prevent any noticeable differences in brightness at the overlaid areas.
Warping refers to the precise adjustment of projected images to match the shape of the surface they are displayed on. You might have seen projection mapping, where images beautifully align with buildings, or projections on curved surfaces like spheres, domes, or cylinders. These techniques are often used in professional AV & Entertainment projects and simulators, where surfaces can have unique shapes, such as curved or complex structures.
To achieve a geometrically and visually accurate representation (warping and blending) on each individual screen, adjustments can be made either manually, which can be time-consuming, or with the assistance of software. The software approach can utilize cameras, and it is commonly known as camera-based alignment.
System for multiple projctor alignment with a separate image generator and a control PC
The domeprojection ProjectionTools consist of several interconnected software components. The measurement process starts with an initial recording of the room's geometry and the optical measurement of each individual projection surface, with the assistance of the installed camera or cameras. Used tools: ProjectionTools Creator (CR) and the PatternGenerator (PG).
The measurement result is captured and calculated by the Mapper 2D (2D) tool. With the assistance of the integrated Clipping Editor feature, the edges of the image and other desired areas can be cleanly masked if needed. The final result is then exported, providing various exporter options for different hardware/software products.
ProjectionTools supports a wide range of well-known projector manufacturers, including Barco, Norxe, and even consumer-grade projectors. Moreover, the system is compatible with nearly all professional media server systems, such as Watchout, Resolume, Pixera, and Green Hippo etc. Click here to see all supported media server and here to see all supported image generators.
