Sensor Technology
Global shutter sensor technology optimises next-generation industrial machine vision products
By Kelly Yan, staff marketing manager, OMNIVISION C
MOS image sensor resolution requirements are dramatically increasing for machine vision applications, a growing market that includes barcode scanners for logistics and retail, factory automation cameras, vision-guided robots and intelligent transport surveillance (ITS).
According to a recent Yole Intelligence Machine Vision report1
, in 2023, the
industrial machine vision camera market was estimated at $6.9 billion. It is expected to reach $7.8B by 2029, registering a 2.1 per cent CAGR23-29. The segment of high-end barcode scanners used in factory and warehouse automation is expected to be the most dynamic with a 3.5 per cent CAGR23-29 transitioning from $655 million in 2023 to $805 million by 2029. This is due to increasing demand for turnkey and versatile solutions, characteristics enabled by the use of image sensors with higher resolution and sensitivity.
Some of the challenges today that machine vision manufacturers are facing include maintaining image quality at high capture speeds, operability under low light, and cost-effectiveness.
New global shutter backside illuminated (BSI) image sensor technology is ideally suited to address these challenges. BSI technology delivers higher quality and better pixel performance in a compact design. Its large angular response makes it easy to match an F1.4 or even larger aperture lens to improve image performance. It offers the best shutter efficiency, which helps to provide high image quality with short exposure time. Additionally, BSI combined with Nyxel technology improves the image-capture capabilities, in both visible light and near- infrared, of industrial machine vision systems. This article provides an overview of the machine vision challenges and BSI sensor technology, with a specific use case example focused on the barcode scanner market.
14 October 2024
undistorted images at high speeds. Because all the pixels on the GS sensor expose simultaneously, these sensors can precisely freeze image motion, eliminating the blur or wobble that can happen with traditional sensors during rapid panning or when capturing fast-moving subjects. In industrial applications, barcode scanners require the ability to quickly, accurately, and reliably capture all encoded data. This presents a significant opportunity for GS sensors. There are two new GS sensors that specifically address the needs of next- generation industrial barcode scanners: the OG05B1B and OG01H1B.
Figure 1. Industrial barcodes appear on a variety of surface types and in varying sizes. To better accommodate this broad range of barcodes, scanners need new types of CMOS image sensors.
What are industrial barcode scanners?
Industrial barcodes, both 1D (linear) and 2D, are used to track virtually every item utilized in manufacturing, packaging, and shipping for industrial and commercial settings. Applications include high-speed production, inventory/warehouse management, supply chain logistics, healthcare, and many others. Barcode scanners are machine vision systems that capture and decode the information contained in a barcode. Manufactured as handheld wireless units (“scan guns”) – and, increasingly, factory- automation cameras – these scanners acquire, decipher, and report large quantities of data quickly and accurately. Figure 1 shows some different types of barcodes and surfaces that industrial scanners must be able to accommodate to acquire data accurately.
Opportunities for technology improvement
Image-based systems have largely supplanted laser technology in industrial barcode scanners because they are more reliable and can read 2D as well as 1D codes. However, they face
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some emerging challenges for which new types of image sensors are required. Barcode scanners themselves are getting smaller, which is necessary both for better overall cost- effectiveness and for better integration with other devices. In turn, the image sensors that power the capture capability must be smaller while being able to operate at higher speeds and deliver superior performance without driving up overall scanner cost. Global shutter (GS) image sensors are industrial devices that capture high-quality,
Global shutter CMOS image sensors The GS image sensors feature the industry’s smallest 2.2-micron (µm) backside-illuminated (BSI) pixel for high resolution in a compact design. The sensors deliver high resolution in a small format, and with their ability to capture high-speed moving objects clearly and accurately at high frame rates, they provide the highest available shutter efficiency. They also feature high sensitivity, low noise, and enhanced near-infrared (NIR) quantum efficiency (QE) for industry-leading low-light performance (Figure 2).
Compared to earlier-generation 2.5µm frontside-illuminated (FSI) GS sensors, the
Figure 2. The first two images (top) were scanned using an FSI GS sensor, and the second two (below) were scanned using a BSI GS sensor.
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