From image-guided surgery to vision-equipped service robots, real-time video is enabling new levels of precision and treatment while driving fundamental changes in how healthcare services are delivered. However, as medical imaging applications multiply and systems become more complex, designers are increasingly challenged to improve system usability and drive down costs.
Even as imaging systems handle increasingly sophisticated analyses, they must be intuitive and easy to use for staff in operating rooms, nursing stations, and healthcare clinics. Budget pressures mean performance enhancements must be achieved without sacrificing investments in existing imaging and processing equipment. Finally, systems must be simple and cost-effective to maintain and scale.
An important first step towards meeting these challenges is choosing the right video interface—the hardware and software used to format imaging data, send it over a cable or wirelessly, and receive it at a computer or display. Although the video interface is a small part of the overall system, it has a large impact on the usability, cost, and future scalability of the final product.
This article describes the video interfaces used today in medical imaging systems for digital radiography and compares them to two interfaces—GigE Vision® and USB3™ Vision—initially developed for and deployed in industrial machine vision applications. It discusses the cost and performance benefits of GigE Vision and USB3 Vision in medical imaging, with specific examples of how they can be used in networked operating rooms and telepresence applications.
Machine Vision and Medical Imaging
A bin-picking factory robot and an image-guided surgery system may seem worlds apart, but video interface standards developed for industrial applications are playing an important role in the continuing evolution of medical imaging.
Like their high-speed industrial counterparts, medical imaging applications require video interfaces that can reliably transfer high-resolution imaging data in real time between cameras or image sensors and computers or displays with low, consistent latency (or delay). Legacy medical imaging systems typically rely on point-to-point interfaces based on custom equipment to meet these requirements. However, developing proprietary interfaces is expensive, time-consuming, takes valuable resources away from developing core functionality, adds maintenance costs, and poses scalability challenges in multi-vendor environments.
As a result, many medical designers have leveraged video standards from other markets, including the TIA/EIA-644 low-voltage differential signaling (LVDS) standard commonly found in telecom and consumer applications, the HDMI/DVI television standard, and the Camera Link® machine vision standard. While all three of these standards support high-performance, real-time video delivery, they require a dedicated connection between each camera and end-point and a PCiE frame grabber to capture data. As medical imaging systems grow in sophistication, these limitations drive up cost and system complexity.
For example, in applications where images are displayed across multiple screens, such as image-guided surgery, the cabling required for umbilical connections becomes costly and difficult to manage and scale. Moreover, the PCIe frame grabber needed at each endpoint limits the types of computers that can be used, drives up component costs, and increases complexity. Endusers are also “locked in” to the frame grabber vendor for support, relying on them to write drivers for specific operating systems and processing architectures. In addition, expensive switching equipment is required to support realtime video networking.
The machine vision industry faced similar issues, and in response released the GigE Vision standard for high-speed video delivery over commercial GigE equipment in 2004. GigE Vision enables the transmission of full-resolution, uncompressed video with low, consistent latency and device commands between an imaging source and an existing port on a computing platform over any Ethernet connection, including over a GigE, 10 GigE, or 802.11 wireless. GigE Vision additionally supports transmission of DICOM-compatible metadata and compressed images (JPEG, JPEG 2000, and H.264). Today, GigE Vision is the most widely used video interface standard in industrial applications and is steadily gaining a foothold in medical imaging systems.