Silicon Software LightBridge: External Grabber with Thunderbolt
15 Oct 2014
A Frame Grabber performs its work while installed in a PC. Until now, this statement has been virtually axiomatic but our partner Silicon Software will challenge the assertion with its presentation of LightBridge, a new production concept being unveiled to the public by the company at VISION 2014. It is defined as an external image recording and imaging component, and does in fact constitute an external Frame Grabber.
LightBridge is a fanless system in a compact housing measuring 10.5 x 12.5 x 5.5 cm³. It is connected to the host PC by means of an electric or optical Thunderbolt cable. Many existing PCs already have a Thunderbolt connection, but even for PCs without Thunderbolt, Silicon Software has a solution ready, in the form of a half-height Thunderbolt expansion card for a PCle x4 slot.
Thunderbolt delivers a range of advantages. The interface is entirely based on PCle and is perceived by the PC system as an expansion of the mainboard buses. That means that no driver is required, nor is there any other overhead. Furthermore, Thunderbolt delivers the robustness of PCle technology and requires none of the extra cost of software adaptation. Thunderbolt is fully compatible with an internal Frame Grabber.
Thunderbolt variants with 1 GB/s and 2 GB/s are currently available, although technology partners Intel and Apple have already announced faster versions. In its first version, LightBridge is being applied to the 1 GB/s version that offers sufficient bandwidth for CameraLink. Subsequent versions that should support faster standards such as CoaXPress and CameraLink HS will be equipped with faster Thunderbolt chips.
Another strength: Thunderbolt has also been standardised for electrical as well as for optical data transmission. Three large manufacturers are now offering optical cables in lengths of up to 100 metres. These are compact, flexible and are certified for a high number of bending cycles, and are capable of coping with torsion loadings. As well as the cable length, the resistance to interference of fibre-optic connections in an industrial environment is of great importance and there are already cables with plug connections to assure robust links.
LightBridge was designed with two Thunderbolt connections and enables in-line circuits with up to six terminal devices. The expansion of an imaging or machine vision system through the addition of more cameras is therefore a feasible proposition at any time in the context of the total bandwidth of Thunderbolt. The camera inputs currently available include two CameraLink connections. The hardware concept allows for modular variant formation to provide additional digital interfaces.
The signal processing concept is designed to control imaging peripherals with its optically discrete inputs and outputs. An RS485 plug connection is provided for PLC compatibility and for synchronisation tasks. When using several LightBridge systems, these can be synchronised automatically. Silicon Software will be implementing field bus protocols directly for future generations. LightBridge will be posting status messages or will be loading configuration data relating to this. Due to the special feature that enables users to program the LightBridge FPGA, complete imaging tasks can be computed in the system and can communicate their status via the PLC.
The heart of the LightBridge is an FPGA. This takes charge of the image capture and image pre-processing tasks, guaranteeing signal processing operations with minimum latency. There are also plans for a programmable version of LightBridge. Customers will then be able to program the FPGA graphically via VisualApplets to suit their specific needs. The user decides how to use LightBridge by programming the FPGA. From simple imaging, e.g. the computing of several rows of images from different cameras to form a single row, or standalone imaging tasks such as the sorting of glass particles by colour and size with automatic rejection, the range of applications depends solely on the extent of available FPGA resources. Even in the non-industrial sector, Silicon Software perceives new fields of application, e.g. in medical technology or in the sport and entertainment sector.
LightBridge is committed to the intelligent integration and connection of existing technologies while nonetheless creating a new category of imaging products and potential applications. The key advantages of this innovation are that LightBridge can be pre-configured and, when necessary, be be replaced within minutes. This cuts down expensive downtime periods for the user.