Perfect 3D Video Mapping on Buildings and other Objects
disguise is one of the world’s leading providers of experience production software delivering spectacular visual experiences at live events with 3D camera/projector systems. Supported by STEMMER IMAGING's know-how and services, the company enables video content to be projected perfectly onto complex geometric surfaces such as stages, cars, buildings and domes – for example at rock concert tours for U2, Beyoncé and Ariana Grande.
The task
Component selection and design support for a system that quickly and reliably calibrates projectors and surfaces for accurate projection of all video content.
The challenge
At live events, there is very little time available for calibration. In addition, the projectors have to be recalibrated at each new venue.
The solution
With carefully matched vision components, STEMMER IMAGING enabled disguise's experts to expand the OmniCal manual calibration system into a scalable, camera-based system that ensures significantly faster yet even more reliable calibration.
In addition to pre-configuring and testing the camera systems, STEMMER IMAGING also takes care of the entire logistics process and delivers the systems with customer branding directly to the event organisers.
Fast, high-precision calibration of projectors for complex 3D video mapping
The 3D projections need to be carefully aligned to accurately match the projection surfaces to ensure that imagery is not distorted in any way.
Disguise software OmniCal actually includes a manual calibration system, which works very well. However, the effort required for the manual calibration of each individual projector was too high for use in live shows. In most cases this requires the use of multiple projectors to achieve the coverage needed. It is rarely possible to build a stage set that does not have any physical disparities in the positioning of projection surfaces compared to the 3D model. This is particularly true of touring productions where the set has to be dismantled then re-assembled at each new venue.
"disguise software actually includes a manual calibration system, which works very well, but time is a critical factor during a live show set up. Technicians working on the projections are competing for access to the set with a host of other personnel working on different aspects of the production. The manual process to calibrate a set of projectors and surfaces typically takes minutes per projector and has a roughly linear scale, meaning the larger the number of projectors the more people or more time would be needed to complete it.“
Peter Kirkup, Global Technical Solutions Manager at disguise
The tailor-made solution: a scalable, camera-based calibration system for even faster and more accurate calibration
Using state-of-the-art industrial cameras and lenses, the STEMMER IMAGING experts helped disguise turn OmniCal into a completely scalable camera-based system. Calibrations can be done in significantly less time because the point cloud generated can be used for all the projectors, enabling parallel calibrations rather than lots of individual manual processes.
The OmniCal system enables higher-quality calibration than a manually operated system. Not only that, it enables a significant new feature with the correction of differences between 3D models and the real-world surfaces. Considering the daily set-up at new venues, this is a decisive extra functionality for 3D projection mapping.
Perfect images for perfect 3D video mapping
Although stereo imaging for point cloud generation is a well-established machine vision application, there were some very specific technical requirements for OmniCal that STEMMER IMAGING was able to fulfil. The cameras are used to capture a short series of images of structured light patterns projected onto the scene to be calibrated. To prevent any areas of the scene being occluded, the sequences of patterns are generated from projectors in a variety of locations.
With OmniCal being used in a wide range of settings, it is essential that the imaging system includes high quality optics with reliable behaviour with regards to focal length and distortion variance. GigE Vision cameras are required, since the positioning of the cameras will vary depending on the particular setting and they may be located at a significant distance from the control system.
The solution's key success factors
When selecting the optimal components for disguise’s customised solution, STEMMER IMAGING was able to draw on an extensive product range from leading manufacturers topped with its comprehensive services. In the meantime, STEMMER IMAGING takes care of the entire pre-configuration and handles the global logistics process all the way to the event locations.
High-performance cameras
The cameras selected for OmniCal are 5 MPixel GigE Vision cameras from Allied Vision with Power over Ethernet simplifying set-up. The cameras feature a high-performance Sony Pregius CMOS sensor with a global shutter ensuring no smearing in the image as the projection patterns are switched.
Reliable pre-configuration
disguise systems are deployed globally and in general, there is very little time available during set-up in which to perform the calibration. That is why STEMMER IMAGING takes care of the entire pre-configuration of all systems ensuring that every OmniCal camera and lens system performs in an identical fashion.
High-speed image data transmission
The positioning of the cameras will vary depending on the particular setting and they may be located at a significant distance from the control system. This is why STEMMER IMAGING opted for the GigE Vision standard for data transmission, which allows high-speed image data transmission in real time over distances up to 100 metres using standard Ethernet Cat 6 cable.
Easy to use
Once the camera is plugged in, all that needs to be done is to set up the camera parameters such as exposure time and focus at the particular event. The technicians on site, who are often not experts in machine vision, can concentrate on the performance aspects of the projections.
Easy handling of lenses
The lenses were chosen for their ease of use and reliability. Depending on the stage area set-up, a mixture of 6 mm, 8 mm and 12 mm focal length C-mount lenses are used which match the resolution of the cameras and feature minimal and consistent distortion properties.
High-precision error correction
A generated 3D point cloud allows correction for the position and orientation of projectors and projection surfaces, as well as the actual structure of the surfaces, achieving sub-pixel accuracy. With respect to differences in projection surfaces, this translates to correcting for errors in the 3D model at large scale, as well as down to the millimetre range.
Unrivalled added value
With customised services, STEMMER IMAGING enables an enormous range of configurations and the need to deploy to anywhere in the world on demand. In addition to pre-configuring the cameras, we are able to hold them in stock as kits complete with a selection of lenses, pre-packaged in flight-ready protective cases for immediate shipment to end users anywhere in the world.
- Camera casing with disguise branding
- The cameras are mounted on a tripod adapter ready for deployment at the venue
- All cameras are supplied with a set of matching lenses
- Each image sensor surface is cleaned before the camera is dispatched
- All cameras are shipped with the original firmware version
“Due to the high production speeds, without this system, it would have been impossible to replace the former random checks with a reliable 100% inspection of the contours while simultaneously checking for leaks, thus increasing the cost-effectiveness of our processes to the current higher level.”
Julian Schmidt, Production Engineer at Novelis
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