We have updated our ePaper on considerations when choosing a machine vision interface. This free paper now includes details on USB3 Vision as well as updates on CoaXPress, Camera Link HS, 10 GigE Vision, and USB3 Vision.
There are several video interface options currently available to connect various elements of imaging systems for machine vision, medical, outdoor and military applications. At the higher end of the performance range, standards such as Camera Link and GigE Vision have served their users well for the past decade, a period which ushered in an era of interface standardization in the industry. But new demands from systems makers, combined with improvements in camera performance and technical innovations in interface technology, are resulting in a second wave of high-speed connection options being developed. These include CoaxPress, Camera Link HS, 10 GigE Vision (GigE Vision over 10 GigE), and USB3 Vision.
Given that cabling/connection media can account for up to 50% of a system’s upgrade costs, the physical interface is extremely important. When considering a move to one of the emerging high-performance options, system developers must carefully weigh the tradeoffs across a range of criteria, including cost (initial and long-term), speed, ease of implementation and use, power, supplier support, and physical connection requirements in order to choose the best connectivity alternative for their specific application.
Each interface offers a unique approach to addressing the range of challenges present in modern imaging systems:
- GigE Vision: Used in low- & mid-end vision systems with less critical speed and timing demands; cost effective solution when full speed is not required
- Camera Link: Industry default choice for higher speed connectivity where limited cable length and high cable costs are acceptable
- CoaXPress: A new standard for applications that require higher speeds, longer cable lengths, and a single, flexible and inexpensive cable; frame grabber still required
- Camera Link HS: Originally designed to overcome the speed limitations of Camera Link for line scan cameras; first products may enter the market end of 2012
- 10 GigE Vision: Built on GigE Vision, faster physical layer and better timing accuracy with much higher power consumption; requires server grade equipment for implementation
- USB3 Vision: Based on existing, well defined USB 2.0 and 3.0 with machine vision specific features. 10x faster than USB-2.0 over shorter cable lengths; interesting step forward for USB 2.0 and FireWire based camera users
No more trade offs
Until recently, there were only 2 choices for demanding imaging applications: Camera Link for higher speeds but with short cable lengths or GigE Vision for longer cables but slower speeds. Essentially, a trade off always had to be made.
As a result, several initiatives are well underway that focus on improving camera interfaces to support the needed bandwidth, as well as provide cost-effective, scalable approaches. Each offer unique advantages and limitations. Developers of camera-dependent systems should evaluate their specific application requirements and understand the differences between the options available.
Important considerations -- beyond just raw performance -- are:
- Ability to easily integrate with existing system architecture
- Flexibility of the connection medium
- Scalability of solution to meet future requirements
- Physical infrastructure for application
- Transmission distance required
- Overall implementation cost
- Availability of products based on the interface
When considering an interface, it is important to understand both its current availability status, as well as the industry support behind it for future implementation in vision systems. The ability of the standard to grow with your product roadmap will eliminate costly changes.