A promising new 3D vision system now makes inspecting 3D parts as easy as using a 2D smart camera. Whereas optical 3D inspection used to require a lot of programming but offered few advantages, the new technology from Cognex brings, according to the American manufacturer, "improved image quality, simplified application development and a wide range of 3D inspection tools - significantly expanding the range of applications in industrial automation."
When it comes to inspecting parts, users can choose from a number of established technologies. If the decision is made in favor of machine vision, the question arises as to whether 2D or 3D inspection is required, and how much effort is needed to implement the corresponding solution. Depending on the application, a proven 2D system is often the first choice, even if the (theoretical) advantages of 3D image processing may be obvious.
According to Cognex, until now, there was no 3D vision system that met the ease-of-use and cost requirements of most inspection applications. 3D vision inspection was simply too expensive and complicated for most companies, and there were also few vision tools that worked with true 3D images. So an additional PC had to be installed to solve the application, which required a lot more space and programming.
On the other hand, 2D inspection with a smart camera works very reliably and with great ease of use. Consequently, in many cases, there is or was no real need to make the costly and difficult transition to a 3D inspection system.
New possibilities for automatic 3D inspection
This situation is about to change with the introduction of the In-Sight 3D-L4000 vision system from machine vision specialist Cognex. This intelligent camera, the only one of its kind according to its designers, enables engineers to solve a whole range of in-line inspection, guidance and measurement applications on automated production lines quickly, accurately and cost-effectively. It offers a full suite of true 3D vision tools that are as easy to use as Cognex's industry-proven 2D vision tools, thanks to the familiar and robust In-Sight spreadsheet environment. What's more, the patented glare-free blue laser optics are an industry first, enabling the capture of high-quality 3D images.
Blue laser optics make the difference
Users of 3D image processing are probably familiar with this: in general, 3D imaging systems are confronted with reflections - light effects that occur when laser light is scattered from the surface of the part towards the imaging system. Reflection is a problem in existing 3D vision systems, as it alters the appearance of the part and reduces image accuracy. The system can only estimate where the laser is located. To date, no 3D system has been able to eliminate these reflections and thus produce images good enough for reliable 3D inspection applications.
However, the type of laser used in the In-Sight 3D-L4000 represents a major technical advance in laser imaging, and explains the excellent results obtained. The 3D-L4000 eliminates reflections by using a special laser in the blue light range. The imager therefore sees a clear laser line, enabling more accurate 3D images. What's more, the laser provides its own illumination for both 3D and 2D images; the system requires no external light.
Intelligent processing of 3D point clouds on real images
In most "traditional" laser-based 3D vision systems, the laser head captures an image which is sent to a PC for processing. At the same time, they offer a limited selection of tools, most of which can only be used for simple height measurement. Dependence on PC programming makes 3D inspections cost-effective only for highly complex applications. The In-Sight 3D-L4000, on the other hand, has built-in processing power. This enables vision tools to perform true 3D point cloud inspections without the need for an external controller or third-party PC software. An interesting side benefit is that, with integrated processing, image analysis can be carried out in a very short time.
In the past, 3D visual inspection was difficult to understand and use. Most existing systems transform 3D data into 2D images. In doing so, the height of a point is represented by a gray value. To understand the height information, we therefore use a false-color representation of the 3D image rasterized in the 2D image. In this representation, it is very difficult to see and successfully process the nuances of the 3D part. A common method is to convert part of the rasterized 2D image into a 1D height profile. However, with the new technology used in the 3D-L4000, the image is a pure point cloud; what you see and evaluate is a true 3D image, not a reduction to a 1D height profile. And since 3D inspection is new to most users, the 3D tools are designed so that everyone can understand and make full use of the new three-dimensional tools. In other words, you're essentially doing the same thing, but unlike before, you're working on an image that looks exactly like the part itself.
Intuitive configuration
Another new feature of the In-Sight 3D-L4000 is the use of the intuitive In-Sight Spreadsheet development interface to quickly and easily configure and run 3D applications without the need for external programming or processing. It simplifies application development and streamlines factory integration thanks to a comprehensive set of I/O and communication functions. It also enables 2D and 3D vision tools to be combined in a single application, speeding up deployment.
The In-Sight 3D-L4000 includes all the traditional 3D measurement tools you'd expect from a 3D vision system, such as plane and height determination. In addition, it features a complete set of 3D vision tools such as PatMax3D, Blob3D, 3D Geometry and many others, designed from the outset for inspections in real 3D space. This makes it easy to measure or identify parts or surface irregularities, as well as gaps, edges and angles, even for parts with complex geometries such as pistons or hinges.
A wide range of applications
The technical advances and easy-to-use features of the new 3D-L4000 make it suitable for a wide range of applications in many sectors, including food, consumer products, packaging, automotive, medical devices and electronics. Its ease of use and the fact that no external PC, and therefore no programming skills, are required for setup and processing ultimately make laser-based 3D imaging a viable and affordable option. Automation engineers now have a real choice between 2D and 3D.
Visit the site:
www.cognex.com