An intelligent camera that is as tiny as a sugar cube and has the computer power of a Core2Duo in a fashionable black housing - sounds good, but unfortunately such a camera is still a figment of our imagination today. Nonetheless, even those of us who could live with a camera that may not be the size of a sugar cube but one that is actually about the size of a package of sugar, would want this camera to have heads that are as small and compact as possible, even if they cannot be shrunk down to the size of a sugar cube either. In such an application, the computer cube would be set up several meters from the camera cubes and would actually be equipped with a dual core CPU. Eltec now offers an innovative camera concept boasting a flexible and scalable image processing solution that meets virtually every expectation.

It is a common phenomenon for innovative concepts to arise from challenges. In the case in point, Eltec was working on a project that involved the development of a successor for a small intelligent camera that had become too slow for today's applications due to its limited computer speed. The objective was to come up with an intelligent camera that substantially boosts data speeds as a result of increased performance and that is still compact enough to fit into a weather guard housing. However, after having been customized for the special requirements of the application, this successor model turned out very differently. It now has up to two offset cameras, utilizes an innovative cable concept for digital image transfer and performs computations with the assistance of a Geode CPU on an ETX module. Despite all of these extras it still fits into the weather guard housing.

CMOS for Compact Designs
The objective was to design cameras that were as small as possible so that two of them could be used right next to each other. Additionally, they were to be equipped with a full frame shutter to get the disturbing oval distortions caused by a rolling shutter out of the picture. CMOS sensors designed for compact structures appeared to be an ideal solution, given that they offer high read-out rates and because they are relatively inexpensive considering their high resolution. How­ever, those that come with the desired shutter, which can freeze an entire image frame upon an impulse, are few and far between. Nonetheless, Eltec found one equipped with a sensor that directly delivers the digital data from the sensor, which made the implementation in a serial LVDS format for the transfers very easy to achieve. The selection of optimum transmission frequencies allows the use of budget priced patch cables for Gigabit Ethernet applications. The lengths of these cables can range from 20 cm to 15 m, which makes it easy to create set-ups that extend from compact to highly distributed. Eltec uses CMOS sensors with wide VGA resolution and a frame rate of 50 Hz (non-interlaced), which are equipped with a freeze frame shutter to ensure the true-to-reality recording of moving objects and make it possible to achieve LVDS transmissions at rates of up to 700 Mbps per channel. Nonetheless, CCD sensor solutions that make it possible to meet special requirements, such as reduced noise levels, are also available. The camera heads, which include the sensors, are small and lightweight.

Complete PC Functionality on a Card
The next engineering challenge was boosting the computing power of the CPU. Even at a 400 MHz cycle, power conservation wizards can be found. The company chose an ETX module that offers all of the functions of a PC on a card. It even has a graphics outlet so that a full operating system with a graphic interface can actually be used. The key specifications of the ETX CPU module comprise the following: one Geode LX-800 CPU boasting 500 MHz, one graphics controller in the chip set with up to 1280x1024 (85 Hz), one PCI interface with 32 bits/33 MHz and a 512 MB SO-DIMM memory on-board.
ETX and COM modules sit on carrier cards, which also provide project-specific I/Os. For the image acquisition process, this particular application called for an interface between the digital camera interface and the hard disk, which is filled by the DMA. An FPGA handles this specific task with power and flexibility. All control outputs utilize the Profibus, i.e. a field bus. Pre-fabricated complete interfaces, which frequently master critical real-time communications and which can be optimally triggered via dual port RAMs, are avail­able on the market. The 160mmx100 mm format media card contains what is needed for the power supply, which operates at a voltage of only 24V/20VA (12 typ.), as well as video inputs via RJ45 plugs, the DMA controller as well as the Profibus interface DP Slave.
The next item on the list was the selection of the software. The decision was made for Linux, which offers a complete development environment (Eclipse). For Linux, the field bus was adapted and a port for the image acquisition process was set up. Debian Linux was used, featuring core 2.6.24, which boots from the on-board flash disk and requires 1 GB of memory space.
To turn all of these components into an intelligent camera, they are fitted into an add-on weather guard housing. By that time, they are already encased by an EMV housing. The distributed utilization of the equipment was tested as well: the LVDS distance between camera and computer core can be expanded to up to 70 m.

A Diverse Range of Applications
Which applications can this innovative camera solution handle? In the concrete case in question, the objective was to create a solution for the recognition of containers in real-time. In the case of video recordings, real-time translates into 40 millisecond delays. Nonetheless, this is obviously just one of many possible implementations. However, the type of camera to be used may or will have to be changed depending on the application: The portfolio also includes CCD sensors for low noise recordings as well as CMOS sensors that boast extremely high resolution levels of up to 5 megapixels and rapid read-outs. The ETX and COM modules can also be adapted to meet the requirements of their pertinent applications, which may include upgrades to up to dual core CPUs with cycles of more than 2 GHz. The media board, which has a project specific structure anyhow, can obviously also be equipped with different field bus interfaces. The number and speed of the camera interfaces can also be modified. The possibilities, depending on specific projects, for which Eltec offers tailor made solutions, are endless.

The innovative camera concept has a modular structure and addresses many diverse applications ranging from the production of electronics to automation and process control to transportation and logistics to security applications. The scalable solution can process up to 32 cameras on a single base unit. Thanks to the industrial duty budget-priced cabling solution, which works with Ethernet patch cables, users can seize the benefits of the entire scope of modern embedded technology applications.

This innovative camera solution encompasses the following basic components:

• Camera heads with CCD and CMOS sensors,
• COM express and ETX-CPU modules,
• Frame grabbers with up to 32 camera connections,
• Computer interfaces with FPGA technology,
• Application-based I/Os,
• Linux software.

The functions that control the camera work independently from the pixel interface via interference protected RS 485 connections. The pixel interface is fully FPGA implemented in the cameras and in the frame grabbers. As a result, multiple cables can be operated in parallel. The error detection solution, which is implemented in the FPGAs, makes it easy to monitor the consistency of the data.
The transmission format was chosen with the objective of attaining maximum transfer rates while simultaneously reducing the cabling costs. The highly cost effective category CAT 5e patch cables, which are used in large numbers in Gigabit Ether­net applications, were determined to be the logical solution. The image data is transferred via an LVDS interface.

High-bandwidth Server Technology
It goes without saying that the computer has to be able to process the data that is transferred from the cameras. In such applications, a standard PC, which has three expansion slots, quickly reaches its limitations. The server technology utilized by Eltec and its extreme bandwidth offers substantial advantages when used in conjunction with applications that involve cameras with high image rates or multiple cameras. The solution allows the connection of up to 20 cameras that all transmit data simultaneously to one single system. The company also offers network interfaces for direct connection to GigE.