At The Vision Show in Boston in May, Teledyne Dalsa demonstrated its support for the AIA’s newest interface standard, Camera Link HS, by showcasing CLHS versions of the Falcon2 camera and Xcelera PX8 frame grabber. The Camera Link HS “competes with all the transmissions standards, but has the unique capability of extreme bandwidth and frame by frame control to take advantage of newly introduced CMOS image sensors,” says Mike Miethig, the R&D camera development manager at Teledyne Dalsa digital imaging.
The idea for the Camera Link HS was born because Dalsa needed a method to reduce cabling for their 1 Gpixel per second time delay and integration product and developed HSLink, which is the base technology for Camera Link HS. “HSLink has been deployed successfully for the past two years,” Miethig says, and, “the concepts were originally formed with a small consortium of companies (Dalsa, Basler, NI, Matrox, Euresys, E2V), but were too advanced in terms of product need and the consortium disbanded without implementation.” But Dalsa had an internal need for the product and the concepts were further developed into the Dalsa HSLink. Then, Miethig says, they “asked for industry participation to improve and make the technology open to the industry.” The result was the formation of the CLHS committee in April 2010.
The Camera Link HS is a new standard that builds on the key strengths of Camera Link, while adding new features and functions to meet customers’ demands. For instance, growing resolution and quicker frame rates have triggered cameras for machine vision systems to increase their need for bandwidth. Camera Link HS addresses this need because it is designed from a system point of view that ensures the ability to create low cost cameras and frame grabbers. At the same time, it is easy to use, flexible and reliable. “The standard will have a long service life… [and] will add new features to address new market needs,” says Miethig.
Furthermore, according to Miethig, the standard is immune to single bit transmission errors and enables real time decisions to be made in the PC and communicated to the camera General Purpose Input/Output (GPIO) or camera acquisition conditions like window location. “CMOS sensors, now coming available, will have on the flu windowing capability and CLHS has been designed to make this new sensor capability available to systems.”
One reason that Miethig says the CLHS is innovative is because it is designed to migrate with telecommunication technology in terms of serializer/deserializer (SerDes) speeds. “Currently, we have approved the use of 3.125 Gbps and 10 Gbps technologies,” he says. The CLHS also uses fiber optic for low cost, long distance, high bandwidth and nose immunity, is designed to handle single bit errors for both real time control and video in packet based systems, ensures device interoperability and reduces development times with the shared Very High Density Logic (VHDL) IP core.
The response to the CLHS has been excellent so far, says Miethig. While it was only released in May of 2012, prototypes of it have been shown since 2010. One of the reasons it has been so well received, Miethig says, is because the fiber optic media and “its small size, high bandwidth, low cost and long distance capabilities. The 2.1 Gbps capability of the C2 (CX4 cable) 15 meter distance is sufficient for most machine vision applications.” Furthermore, Miethig says that the availability of the IP core “simplifies product development and makes it possible for customers that build their own frame grabber or camera to adopt the technology and implement product.”
CLHS will first be used where the other standards are not suitable, such as in the high bandwidth arena (greater than 300 Mbps) where a Camera Link cable is of benefit. It will also be used for applications where there are system benefits of commanding the camera to different operating modes on a frame-by-frame basis based on the computations performed in the PC. Miethig also believes that some low bandwidth applications (300 Mbps) where the camera must be moved will benefit from the use of fiber optic cables due to the light weight, long flex life, noise immunity and low cost of fiber optic.
The CLHS has met customers’ demands by building on the Camera Link by adding new functions and features. According to Miethig, “there is not another standard that has all the real-time capabilities of CLHS.”
Reduces time to market
Reduces cost of support
Improves devices compatibility
Validated and robust
Collective development effort