Enabling machine vision with GMSL

Initially developed to meet the stringent requirements of the automotive industry, GMSL has become a pivotal enabler of machine vision systems. It supports high-definition video, low-latency data transfer, and robust transmission over long distances, often using lightweight, cost-effective cabling. As the capabilities of machine vision continue to expand, the evolution of GMSL technology has kept pace, remaining as a reliable backbone for modern vision systems.

This article delves into the history and evolution of GMSL technology, exploring how it has adapted to meet changing demands. It also examines the role GMSL plays in today’s world, powering cutting-edge machine vision applications, showcasing its impact across industries and its potential moving forward.

GMSL: a history

The development of GMSL technology can be traced back to the increasing demand for high-speed data transmission in the automotive sector. As vehicles began incorporating increased advanced driver-assistance systems (ADAS), manufacturers faced significant challenges in transmitting high-resolution video and sensor data between cameras, radars, and central processing units. Traditional data transfer methods, such as analogue video links or basic digital connectors, came with key problems such as limited bandwidth, interference susceptibility, and often bulky or cost-prohibitive forms which limited large-scale deployment.

To meet these needs, GMSL technology was developed and swiftly emerged as a dominant solution, offering a robust digital communication standard capable of transmitting data at gigabit speeds over lightweight coaxial or shielded twisted-pair cables. Introduced by companies like Maxim Integrated (now part of Analog Devices), GMSL was initially designed for automotive use, providing a reliable means to handle the growing data requirements of ADAS and infotainment systems.

The first-generation GMSL standard addressed the need for transmitting uncompressed video, audio, and control signals over a single cable, simplifying vehicle wiring harnesses and reducing weight. This innovation was critical in enabling the adoption of high-definition cameras and advanced imaging sensors in vehicles, setting the stage for more sophisticated vision-based applications.

As the automotive industry continued to push for higher performance and greater functionality, subsequent iterations of GMSL were developed. Each generation improved upon its predecessor by increasing data bandwidth, enhancing signal integrity, and introducing advanced features like multi-stream capabilities and error correction. These advancements ensured that GMSL could keep pace with the rapid evolution of machine vision systems, extending its relevance beyond automotive applications into industrial automation, robotics, and other domains reliant on high-performance imaging technology.

By addressing the limitations of earlier communication technologies, GMSL established itself as a foundational technology for modern machine vision, paving the way for its continued development and adoption across various industries.

GMSL: a victor amongst competition

GMSL technology did not emerge as the sole solution to the various problems it addressed and faced competition from other high-speed data transmission technologies, such as Gigabit Ethernet (GigE), USB 3.0, and MIPI Cameria Serial Interface 2 (CSI-2).

Each of these technologies has its own strengths, but GMSL has emerged as the preferred choice in many machine vision and automotive applications due to its unique advantages.

One needs only look at a general comparison of the technologies to see why:

Table 1 – Advantages & disadvantages of GMSL, GigE, USB 3.0, and MIPI CSI-2.

Table 2 – A comparison of GMSL, GigE, USB 3.0, and MIPI CSI-2 capabilities.

While GigE, USB 3.0, and MIPI CSI-2 remain viable options for certain use cases, GMSL’s unique combination of features has made it the leading choice for machine vision systems that require high performance, reliability, and scalability.

GMSL: an evolving technology

GMSL has been constantly evolving since its inception, driven by the increasing demands of machine vision systems and advancements in related technologies. This evolution has been centred around addressing the needs for higher data bandwidth, improved signal reliability, and enhanced flexibility in system design. GMSL has seen 3 key generations since its early days:

GMSL1: the foundation

First-generation GMSL, or GMSL1, as previously mentioned, was introduced to address the need for a reliable and efficient method to transmit video, audio, and control data over long distances in automotive applications. GMSL1 offered data rates of up to 3Gbps, supporting uncompressed high-definition video and audio over lightweight coaxial or shielded twisted-pair cables. It also incorporated forward error correction (FEC) to ensure robust signal transmission, even in the presence of electromagnetic interference (EMI), which is common in automotive environments.

GMSL2: enhanced performance and flexibility

As machine vison applications grew more complex, GMSL2 was introduced to meet the increasing demands for higher bandwidth and versatility. GMSL2 nearly doubled the data rate of its predecessor, reaching speeds of up to 6Gbps. This advancement allowed for the transmission of multiple video streams or higher-resolution images, essential for systems which featured multiple cameras or sensors.

One of the key features of GMSL2 was its backward compatibility with GMSL1, enabling smoother upgrades and integration into existing systems. GMSL also supported bidirectional communication over the same cable, enabling simultaneous data transmission and control signal exchange.

GMSL3: high bandwidth for the next generation of applications

GMSL3 is the current generation of the technology, developed to address the demands of cutting-edge applications such as autonomous vehicles, industrial automation, and advanced robotics. GMSL3 increased data rates up to 12Gbps, enabling the transmission of ultra-high-definition (UHD) video, complex sensor data, as well as the new-age AI-driven processing outputs in real-time.

This wasn’t all for GMSL3, which also introduced more advanced features such as adaptive equalisation and advanced error correction techniques, further improving signal integrity over longer cable distances. These enhancements made GMSL3 ideal for environments where consistent and reliable data transmission is critical, such as autonomous driving or factory floor automation.

This evolution of GMSL technology has been driven by several key factors over the years, these being:

• Increased data demands: the rise of machine vision systems with higher-resolution cameras and multiple sensors required significantly greater bandwidth
• Integration of AI and Edge processing: real-time processing at the Edge necessitated faster and more reliable communication between sensors and processors
• Environmental challenges: the need for reliable performance in high-noise, high-vibration environments, such as vehicles and industrial settings, spurred advancements in signal integrity and EMI resistance
• System complexity and cost reduction: simplifying system design by reducing cable counts and integrating multiple data streams over a single connection was a key goal

From GMSL1 to GMSL3, the technology has proven itself as an adaptable solution with continued relevance into the modern era, meeting the demands and challenges of modern machine vision systems. These advancements have made GMSL become a critical technology to specific industries, enabling high-speed, robust, and cost-effective communication.

GMSL: the technology for today

Today, GMSL technology is a cornerstone of modern machine vision systems, providing the high-speed, low-latency communication required to meet the demands of increasingly sophisticated applications. From ADAS to industrial automation and robotics, GMSL has established itself as a versatile and reliable solution for transmitting high-resolution data across a variety of environments.

Key applications:

• Automotive: GMSL is widely used in ADAS and autonomous vehicle systems, where cameras, LiDAR, and radar sensors generate vast amounts of data that must be processed in real time. By enabling high-definition video and sensor data transmission over long distances, GMSL supports critical functions such as lane-keeping, object detection, and adaptive cruise control
• Industrial automation: in smart factories, GMSL enables seamless communication between high-resolution cameras, sensors, and edge processing units. This capability is essential for machine vision applications such as quality control, defect detection, and robotic guidance
• Robotics: advanced robots equipped with vision-based navigation and manipulation systems rely on GMSL to transmit video and sensor data quickly and accurately. Its ability to operate reliably in high-vibration and EMI-heavy environments makes it ideal for robotics deployed in manufacturing, logistics, and exploration

Figure 1 – The MAX9275GTN/V+ from Analog Devices/Maxim Integrated.

The MAX9275/MAX9279 are great examples from Analog Devices/Maxim Integrated of GMSL devices which offer high-performance 3.12Gbps GMSL technology.

These serializers, specifically designed for automotive and industrial applications, support high-definition video, multi-channel audio (up to 192kHz/32-bit), and embedded control channels (up to 1Mbps) for flexible system integration. These serializers drive low-cost 50Ω coax or 100Ω shielded twisted-pair cables, with programmable pre/deemphasis for reliable long-distance transmission (up to 15m). Key features include programmable spread spectrum for EMI reduction, HDCP content protection (MAX9279), and compliance with automotive ESD standards. Ideal for infotainment, navigation, and camera systems, they operate in harsh environments (-40 to +105°C) and come in a compact 56-pin TQFN package.

Figure 2 – Typical GMSL cameras to host connection (Source: Analog Devices)

Key applications of these serializers include high-resolution automotive navigation systems, rear-seat infotainment displays, megapixel camera systems for ADAS and surveillance, in-vehicle networking and multimedia streaming, industrial vision systems, and machine vision applications.

Looking ahead, GMSL is poised to support various emerging technologies and industry trends. Continued integration into AI and Edge computing can be expected with GMSL enabling faster communication between high-resolution sensors and Edge processors. GMSL is likely to also see expanded use with next-generation imaging systems utilising 8k imaging technology. Finally, cross-industry applications will likely grow moving forward, seeing expanding use in healthcare, augmented reality, and other domains requiring robust data transmission.

GMSL technology’s adaptability, performance, and cost-efficiency ensure its continued relevance as a critical enabler of machine vision in diverse industries. From GMSL1 to GMSL3, its evolution highlights its capability to meet the demands of today while preparing for the challenges of tomorrow.