Summary

COBRA is Exxim's implementation of 3D CT reconstruction using the filtered back-projection algorithm (Feldkamp) or Exxim's proprietary algorithm (SAMARA, extended view technology). 

For more information : download and install trial version of COBRA. Additional details are presented in the User Manual.

COBRA can be used as a standalone program or be integrated into the user application. 

Versions  

V1.5

  Nov 2002

First official version, implementation of filtered back-projection algorithm (FDK). Supports in-line reconstruction through COM interface.

V2.x

  Feb 2003

Supports cluster solutions. 

V3.x

  Jul 2003

SDK was supplemented by a DLL interface, which presents COBRA functionality for integration independent of its GUI. Choice between nearest neighbor and bi-linear interpolation in back- projection routine. 

More flexibility for the input and output data format.

V4.x

Feb 2004

Streak and metal artifact reduction supplied by SAMARA implementation.

Faster bi-linear interpolation mode.

Supporting generic scanner geometry  via projection matrices.

V5.x

 Apr 2006

Innovative edge-preserving noise reduction technique.

Geometry calibration utility. 

Extended FOV reconstruction technology.

TCP/IP inter-component communications.

V6.x

Significant speed-up of image reconstruction

by using the optional GPU implementation.

Higher accuracy through floating point format.

Polynomial beam hardening correction.

Iterative correction of Feldkamp artifacts CFA.

Improved geometry calibration utility.

  Performance

COBRA directly replaces other hardware-accelerated versions currently on the market. COBRA efficiently utilizes multi-CPU platforms (dual- or quad), networked PCs (cluster solutions, v.2 and higher) and modern graphics accelerators to achieve fast CT reconstruction (v.6 and higher released in July 2007.  

The PC: Dual Pentium 2.4GHz. Reconstruction of 512 cube volume from 360 input projections of 512 square pixels takes less than 100 seconds (excludes volume storage on HD). 

Using the optional GPU configuration with

nVidia GeForce 285 GTX: less than 18 seconds

  Distributed (cluster) solutions  

COBRA allows distributed calculations. After installion, no user interactions on remote computer(s) are necessary.

Almost linear scaling of speed achievable.

SDK 

The complete COBRA  functionality is available in form of a Software Development Kit (SDK). The SDK provides a choice between two interfaces: DCOM or DLL. DCOM allows incorporating COBRA's functionality into any application, which is compatible with the MS COM model (e.g. language or compiler are not restricted). The DLL interface provides integration into the user application without COBRAs GUI on the PC desktop. 

  Streak and metal artifact reduction

For datasets, which result in streak and metal artifacts in the image, COBRA  provides a special algorithm, which is more tolerant to input data im- perfections. The correction works regardless of the underlying cause, e.g. absorption non-linearities or geometry misalignment.   

The runtime penalty of this reconstruction process  in comparison with standard Feldkamp:

- for streak artifact reduction approx. 2.5 times longer

- for metal artifact reduction approx. 3.5 times longer