Comparing the different interface standards for embedded vision
Embedded vision interfaces vary on the application's specific needs. Mobile industry processor interfaces and USB 3.0 are the most common.
Imaging technology has advanced over the years and with each wave of changes comes a different embedded vision interface. Do you remember your first vision camera? Would you rather not admit what interface it used? Picking the right interface doesn’t just depend on your camera. You’ll need something that works best for your entire system.
Pick your embedded vision interface
Embedded vision is driving the advancement of self-driving cars and intelligent medical devices. To fit in the tight spaces where they need to go, embedded vision devices require simple interfaces. Since embedded devices have such compact form factors there simply is no room for bulky cabling.
Mobile industry processor interface
The Mobile industry processor interface (MIPI CSI-2) standard is the most widely-used embedded vision interface. It was designed for mobile devices and is updated by the MIPI Camera Working Group every two years. Some applications include head-mounted VR devices, IoT appliances, and 3D facial recognition security systems. MIPI has a high bandwidth of 6 Gb/s. It has four image data lanes that are each capable of 1.5 Gb/s. MIPI CSI-2 is faster than USB 3.0. It’s an efficient, reliable protocol that can handle video from 1080p to 8K and beyond. Thanks to its low overhead, it has a higher net image bandwidth. CSI-2 also uses fewer resources from the CPU thanks to its multi-core processors.
USB is most likely the runner-up to MIPI-CSI2. In 2008, USB 3.0 gave the extremely common multipurpose interface a boost to 5 Gb/s. Thanks to its plug-and-play capabilities, embedded vision devices can typically be swapped out with ease, making it easy to replace a damaged camera. If you choose USB 3.0, you can say goodbye to expensive, drawn-out development times and costs for your embedded vision interface. The drawbacks of USB 3.0 usually only make problems for devices in tight spaces. The USB standard calls for rather large connectors and fairly rigid cabling that isn’t ideal for some compact embedded vision components.
A new standard on the horizon
The European Machine Vision Association announced in 2018 that they’d started working on a new embedded vision interface standard. Since embedded vision devices have shrunk in recent years, a new standard is needed to meet the size constraints. The first release candidate is targeted for this year.
This article originally appeared in Vision Online. AIA is a part of the Association for Advancing Automation (A3), a CFE Media content partner. Edited by Keagan Gay, digital media and production coordinator, CFE Media and Technology, firstname.lastname@example.org.