Live, high-resolution imaging is increasingly being leveraged to enhance operating procedures. It can improve the precision of physicians and their instruments, and minimize the invasiveness of many procedures. Increasingly, one small component in a vision system — the interfacing technology — is providing answers to the most common of these challenges.
In particular, the GigE Vision interface standard, which supports real-time, high-resolution, and multi-sensor imaging, is garnering the attention of the medical sector. This article explores how GigE Vision over Gigabit Ethernet (GigE), as well as GigE Vision over 10 GigE, enables substantial innovations in medical imaging.
Streamlining Multi-Sensor Network Architectures
Originally, point-to-point connections between a camera sensor or detector and a computer (PC) were used to achieve real-time functionality. In the operating theater, images often need to be viewed on multiple displays in different areas, even remotely. With a point-to-point architecture, each of these connections requires a dedicated connection, often including its own PC, frame grabber, or display controller. A more efficient architecture would reduce both the complexity and costs of this arrangement.
This became possible in 2006 when the AIA (www.visiononline.org) standardized a set of protocols for transmitting video and control data over Ethernet: the GigE Vision standard. This open, freely available standard provides medical system designers and integrators with a reliable, flexible, and inexpensive interface alternative to more cumbersome and costly legacy options. Furthermore, as the resolution and frame rate of medical imaging devices increases, interfaces will need to accommodate the additional data throughput, and GigE Vision over 10 GigE provides the necessary capacity.
Clinical Benefits of GigE Vision
Medical system designers have been converting legacy analog systems to more powerful digital systems for some time. This is expanding the range of applications for image-guided surgical and diagnostic systems. Common applications of medical imaging now include:
• Computed tomography (CT scan)
• Image-guided or robotic surgery
• Digital radiography
• Dental imaging
• Veterinary radiology
As medical imaging technology evolves, however, it exceeds the capability of both analog interfaces, as well as legacy digital interfaces. Video-over-Ethernet is particularly well suited for these types of applications because it addresses the following common challenges associated with achieving highresolution, real-time video:
Accommodating High-Resolution Images
Interfaces traditionally used in imaging equipment do not have the bandwidth required to carry the advanced resolution and high frame rates necessary in many modern medical imaging applications.
Video compression is a standard coding practice used to reduce the size of video files while maintaining the integrity of the image. The process, however, adds latency to image transmission and can reduce image detail. Latency must be reduced to a point where movement on the display is practically indistinguishable from that of a surgeon’s direct visual perception. Most system designers aim for an end-to-end latency of 200 ms or less, a figure achieved by careful selection of the interface and networking technology, including an optimized implementation of the GigE Vision standard.
Gigabit Ethernet (both at 1 and 10 Gbps) is particularly well suited to accommodate high data rates, and so compression is not required in most cases. The GigE Vision standard employs a lowoverhead network protocol, and can benefit from the use of jumbo Ethernet frames, thereby reducing the overhead even further.