The State of Machine Vision

Technology development is being driven by market pressure from the creation of functionalities enabled by technology development. From smart facilities and buildings to smart vehicles and roads, solutions based on the latest core technologies are empowering designers in the creation of advanced industrial products.

There is no precision in any system without some kind of observation and feedback. That input can be from something as simple as a pressure switch or as complex as a LIDAR sensor. The ability to see something and gain information from it is a powerful enabler in a system, and machine vision provides that functionality in advanced automated systems.

A machine vision system is made up of task-related subsystems. Their number and function will vary depending on the system’s targeted image resolution, speed, memory, and functionality. In general, however, machine vision requires subsystems for capture, processing, and communication.

One must have an image, turn it into data, and send that data to the network. Points added if you can accept commands and adjust your operating parameters on the fly.

Cameras

Highly integrated cameras are available that incorporate the necessary electronics for the desired functionality. Not only do they have to deliver in the area of resolution and speed, but they also have to perform in a potentially harsh industrial environment.

The Cognex In-Sight 9000 family of ultra-high-resolution vision systems can acquire detailed images for high-accuracy parts location, measurement, and inspection, even when mounted at a distance. The 9902L is a 2K line scan camera; the 9912 does a 12-megapixel area scan. Both are IP67-rated for use in demanding factory environments. The company’s In-Sight Explorer EasyBuilder interface provides an integrated solution to simplify application design and setup. Cognex’s vision tools and technologies include PatMax RedLine pattern matching and High Dynamic Range Plus (HDR+) technology.

The Alvium Camera Series addresses limitations associated with legacy camera modules.
(Image: Allied Vision)

Allied Vision’s Alvium camera series offers a selection of current sensors, intelligent power management, and cost-optimized design to address limitations associated with legacy camera modules. The Alvium 1500 offers a Mobile Industry Processor Interface Alliance (MIPI) CSI-2 camera serial interface, with software integration realized via Video4Linux2 or GStreamer. Image-preprocessing functionality can be configured directly on the image, and depending on the application requirements, a Direct Register Access is available to enable full control of the camera.

The Alvium 1800, with an advanced feature set for image correction and optimization, can be used for industrial embedded vision or machine vision applications. Designers can choose advanced image-processing functionalities for their embedded vision application that can be operated directly on the camera. For camera control, the series supports Video4Linux2 (V4L2), direct register access, and the Generic Interface for Cameras (GenICam).

The newest interface available for connecting cameras to systems for machine vision applications is 10 Gigabit Ethernet (10GigE). The touted benefits of 10GigE cameras are excellent speed and distance performance, quick and simple setup, reliability, backward compatibility with Gigabit Ethernet, efficient CPU usage, and GigE Vision compliance. Companies such as Imperx have recently added 10GigE cameras, with models that can deliver 31- and 25-Mpixel resolution.

For cost-sensitive applications, Imperx offers the Cheetah 3MP, which has a tiny form factor but packs a Sony IMX265 CMOS. Available in color or monochrome, the camera offers excellent sensitivity, a wide dynamic range, and an upgradable feature set for ease of integration, according to Imperx. The Imperx CMOS Cheetah 5MP, with a SONY IMX250 sensor, has polarization features to minimize glare from reflective surfaces as well as help visualize internal tensions and stresses within transparent materials.

Boards and Modules

The board your camera plugs into is another important part of the system with implications for the final product’s performance. Among the companies addressing advanced computing is congatec, which released new versions of its NXP i.MX 8-based Smart Mobility Architecture (SMARC) 2.0 and Qseven modules last fall at electronica (Figure 3). The small-form-factor modules are particularly suited for ultralow-power, high-reliability industrial applications, according to congatec.

Leveraging the power-efficient Arm Cortex-A35 architecture, the i.MX 8X modules offer advanced processing and graphics performance, scaling from two to four cores. Features of the 2- to 4-W embedded computer modules include an extended temperature range from –40°C to +85°C; domain resource partitioning; high-bandwidth, low-power double-data-rate LPDDR4 memory; and real-time, IEEE 1588-compliant Ethernet support for devices connected to the internet of things (IoT).

Leveraging the power-efficient Arm Cortex-A35 architecture, the i.MX 8X modules offer advanced processing and graphics performance, scaling from two to four cores. Features of the 2- to 4-W embedded computer modules include an extended temperature range from –40°C to +85°C; domain resource partitioning; high-bandwidth, low-power double-data-rate LPDDR4 memory; and real-time, IEEE 1588-compliant Ethernet support for devices connected to the internet of things (IoT).

Cognex’s In-Sight 9000 family of ultra-high-resolution vision systems perform high-accuracy part location, measurement, and inspection. (Image: Cognex)

Axiomtek supports factory automation, Industrial IoT (IIoT) gateway systems, and machine vision with the PICO318, a palm-sized fanless Pico-ITX motherboard powered by the Intel Pentium N4200 or Apollo Lake N3350 Celeron processor. The low-power, 2.5-inch embedded board is equipped with a 204-pin, DDR3L-1867 small-outline dual-in-line memory module (SO-DIMM) for up to 8 Gbytes of system memory. A dual-display capability is available through 18/24-bit single/dual-channel low-voltage differential signaling (LVDS) and DisplayPort.

The modules have a M.2 key B slot for a Serial ATA (SATA) or PCI Express x2 SSD card, as well as a half-size Mini PCIe slot with support for Mini-SATA, and a 12-volt DC power input with AT auto power-on.

I/O connectivity includes two USB 3.0 ports, two USB 2.0 ports, one RS-232/422/485 port, one RS-232 port, two Gigabit LAN ports with Intel i211AT Ethernet controller, one HD Codec audio, and four-channel digital I/O. Features include a watchdog timer and hardware monitoring as well as support for AXView 2.0, intelligent remote management software for industrial IoT applications, and an I2C interface with smart battery support.

Comms Is Key

Of course, no matter how sophisticated your vision system is, if it can’t communicate well with the rest of the process, it loses value. Once a machine vision camera is connected to a communicating network or the cloud, it becomes a critical sensing tool that not only allows you to control a process, but also can help you draw insight from the captured images. Interfaces such as Camera Link, GigE Vision and USB 3.0 continue to offer an affordable value proposition in low-end applications. But alternatives are emerging to deliver the bandwidth and latency performance required for transmitting decision-triggering data in advanced industrial IoT applications.

NXP i.MX 8-based SMARC 2.0 and Qseven modules from congatec serve ultralow-power and highreliability industrial applications. (Image: congatec)

Among them is CoaXPress (CXP), a high-speed, high-capacity interface that makes it possible to transmit data-laden live images that can help systems identify patterns and make decisions on the spot. CXP allows video, camera control for triggering, and power to be delivered via a single coaxial cable at high speeds, with CoaXPress V2.0 offering 10-Gbit/second (CXP-10) and 12.5-Gbit/s (CXP-12) communications.

The Cyton-CXP4 four-channel frame grabber from BitFlow incorporates a Gen 2.0 x8 PCI Express bus interface on its back end while supporting CoaXPress on its front end for capture speeds of up to 6.250 Gbits/s in applications deploying up to four CXP-6 cameras. It supports not only simple triggering modes but also complicated, application-specific triggering and control interactions within any hardware environment.

Vision is a critical enabler in any automated system and adds critical value on the manufacturing floor. Proper vision subsystem selection and integration are key to creating an optimal solution for industrial vision systems.  ■