Geometric Correction

Geometric Correction
Geometric correction via image warping is our process of digitally manipulating the image to provide the smoothest possible transformation between projected images. Our advanced algorithms geometrically align pixels from adjacent projectors while minimizing distortions.
Warp Mesh
A warp mesh is an "instruction" describing how to manipulate pixels to achieve a desired geometric result. The output of the Scalable calibration process is the "Scalable Mesh File" (SMF). The SMF is delivered to a piece of hardware where the instructions are processed as describe below.
Warping Processors
There are two primary hardware platforms where the SMF can be processed: 1) External Image Processors - Warping Boxes 2) Graphics Processing Unit (GPU)

Warping Boxes

Warping Boxes are high performance scalers which deliver geometric warping capability. These devices, which range in size from 1U to 4U, support a wide range of input signals and high quality scaling and de-interlacing. Generally speaking these boxes offer a great degree of flexibility because they meet the extreme warping requirements of domes and toroid screens. Scalable has invested significant resources over many years to develop elegant interface to several of the leading boxes on the market. Examples of warping boxes that accept the SMF are: Barco MCM-100, WB 1920, WB2560; Calibre 325; Coretronic GB-102; Flexible Picture Systems AI-200; Jupiter WarpBlend node; ScalableIPS.

Graphics Processing Unit (GPU)

There are two distinct ways that the SMF can be processed by the GPU: 1. Scalable has worked with both AMD and Nvidia to develop an interface (API) between the Scalable software and the GPU drivers thus enabling the SMF to be processed by the GPU. The API is available on the AMD FirePro W-600 and W-9000 cards as well as the Nvidia Quadro K-5000 and above cards. 2. When OpenGL or DirectX applications have been modified with our SDK the SMF is processed by the GPU.
Precise Geometric Accuracy
When warping images, video or computer generated as in a flight simulator, the objective is to minimize the geometric distortion experienced as the image transitions from projector to projector. Lack of uniformity in a grid pattern is a classic example of a poorly executed geometric warp. In military environments very precise measurements are taken with a laser emitting theodolite to ensure precision in the geometric warp. Scalable's geometric accuracy has been tested with a theodolite on a dome section and meet the required specifications for accuracy.
Geometric correction is a pillar of the seamless display. Using our groundbreaking camera feedback system, EasyBlend calculates the precise geometric adjustments needed for sub-pixel accuracy in our blend zones. The resulting warp meshes are then executed in hardware or software.