Line Scan Versus Area Scan Technology
Samantha Frost, 08-01-2018
There are two types of acquisition methods to acquire an image of an object—area scan and line scan. The most common 2D machine vision systems use area scan cameras, which require a complete matrix of pixels to be exposed at the moment of acquisition. By contrast, line scan cameras contain a single row of pixels, building the final 2D image pixel line by pixel line. Production and distribution lines in manufacturing and logistics rely on this special technology to acquire high resolution images quickly for detailed part inspections.
In certain applications, line scan systems have specific advantages over area scan systems. But do you know when?
With today’s line scan imagers available from 500 to 8000 pixels per line—and some even able to match high speed line acquisition rates of 67,000 lines per second—the latest generation of line scan cameras generate all the power necessary for applications that formerly required a cluster of high resolution vision imagers. These attributes make line scan cameras an ideal choice for capturing target objects in continuous or discrete “web” surface inspections, such as for plastic, textiles, metal, or paper. Line scan cameras can also “unwrap” cylindrical objects to capture their entire surface area. Large objects that require high-resolution imaging for precise measurement and defect detection--such as flat panel displays, solar cells, and car parts—are also well-suited to this technology. And because line scan systems only need to view a small portion of the target object for each line acquisition, they did not require a large, unobstructed view of the target object. For this reason, they work well in installations with restricted fields of view or mounting space.
As with most machine vision systems, line scan systems can be configured with a camera and PC or vision controller running machine vision software, or as an embedded system with the camera and software contained in one package. So whether for food and beverage, electronics, packaging, or logistics, line scan camera technology can help manufacturers acquire high-resolution images for fast-moving, large, and cylindrical objects that challenge area scan cameras.To find out more about how to line scan camera technology can work your application, download Cognex's free Introduction to Line Scan Vision Technology expert guide.