VESA Updates MPCDI Standard to Include New Color Correction Parameters

The Video Electronics Standards Association (VESA®) today released Version 2.0 of the VESA Multiple Projection Common Data Interchange (MPCDI) Standard.

Developed by VESA’s Multi-Projector Automatic Calibration (MPAC) Task Group, the standard creates a standard data format for multi-projector alignment systems, allowing these systems to produce data that can be easily utilized and integrated by a range of devices, programs and displays. The newest update includes a number of changes intended to mitigate color differences that arise when blending different projectors, enabling greater performance with respect to color consistency, brightness and intensity.

Modern solid-state imaging-based projection systems use fixed pixel numbers and positions. To shape the picture to fit a screen or to overlay an object, it is necessary to modify the shape of the image content in the signal. The techniques involved include edge blending, warping and pixel mapping. Introduced in July 2013, the MPCDI specification seeks to standardize these techniques across multiple manufacturers’ hardware and software offerings.

Version 2.0 of the MPCDI Standard builds on these efforts to allow for color correction so that individual projectors being blended together can be color matched regardless of brand, projector type or projector technology. Full 3D lookup tables are supported so that even DLP projectors, which traditionally are very difficult to color match, can be supported by multi-projector setups.

The new additions to the standard include:

Color definitions – Formatting and storage of lookup tables are defined, along with input color-to-blending-to output color mapping equations and associated use cases.
Color XML specifications – To store the definitions, the XML header was modified to allow pointing to the appropriate files and storage of the non-file correction parameters.
Revised extension example – The original extension example – a color lookup table storing a series of .png files – is now covered in the standard directly. The new example provided is a lookup table for distortion and correction for chromatic aberration, with a separate red-green-blue (RGB) warp.
When combined with the existing standard, these new parameters further enable free interchange of data structures that provide a video definition for both content and intensity of colors that have been altered to allow conformance of multiple images for display as a continuous single image.

“Multi-projection systems are a cornerstone technology for a growing number of markets. These include high-end entertainment venues, military and other training simulators, and air-traffic control systems, as well as emerging virtual reality environments,” said Bei Yang, creative technology executive, Walt Disney Imagineering Research & Development, Inc. “With Version 2.0, we can bring more stability in both geometry and color quality than ever before to projection used in our theme park attractions.”

Also included in the definition of VESA’s MPCDI Standard are geometric data, intensity, color, and topographic information about each of the displays. The purpose of this definition is to simplify the transition between technologies during the lifecycle of a display system.

“Once again, VESA’s MPAC Task Group has worked with the industry to anticipate and address a key requirement for multi-projection implementation,” said Alan Kobayashi, chairman of the VESA Board of Directors. “VESA has a large portfolio of standards addressing areas including display interfaces, video parameters including timing, and compression, and MPCDI has extended our reach into multi-projector systems – in turn, broadening our impact within the display and electronics industries.”