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Application focused vision systems

As machine vision has matured, there has been a lot of research into the more difficult applications.

This resulted in general improvements of algorithms or lighting techniques, however in recent years we have seen solutions that require a close integration of lighting, camera and software to realise a solution that makes the most complex application easy.

These systems are based on years of research and integration, to enable some of the toughest applications to be delivered with lower risk and with less time.

3D smart sensors

Modern 3D smart sensors combine 3D scanning, measurement and control in a single device, with no external PCs or controllers required. This efficient design paired with high performance functionality makes these devices easy to integrate into existing inspection systems. This minimises system cost and maximises product quality and throughput.

Ideally, the sensors are factory pre-calibrated so users can immediately set up the sensor via a web browser and configure functions such as exposure, trigger logic, dimensional measurement tools and communication method. Once the setup is completed, the computer can be disconnected and the device runs in standalone mode.

Shiny surface inspection systems

High end surface inspection systems use e.g. advanced shape from shading technology, which gathers information on the three dimensional shape of an object from its surface shading and visualises this information according to various criteria (slope, curvature, texture). For evaluation purposes, the images generated can be used singly or can be combined. These systems are usually available in a range of versions and models: a core component, a complete system including lens, camera and PC, or a unit integrated into a custom automatic inspection system tailored to specific applications.

Hyperspectral imaging systems

Some applications cannot be solved with standard camera technology. For example, the separation of plastic parts in recycling processes concerning their material properties cannot be performed just by analysing shape and colour. A well-known analysis technology for this task is NIR spectroscopy, which has been used since the 1970's as a tool in process analytics.

Since its first deployment in industry the technology has evolved to spatially resolved spectroscopy, also called hyperspectral imaging (HSI).

Today many different spectral analysis technologies are used in research and industry. A lot of spectrometers are based on line scan sensors and are able to measure a single point of a sample, resulting in a spectrum. Hyperspectral Imaging systems are based on matrix sensors, measuring a multitude of spectra with one image frame.

NIR spectroscopy is a well-known process analysis technology (PAT) used for decades and has evolved into spatially resolved spectroscopy enabling chemical images of a sample.

How does it work?

A spectrograph is attached to an area-scan camera, diffracting the reflected light of the object into a spectrum. This is done with prisms and/or diffraction gratings. Hyperspectral cameras range from X-ray to the far infrared. For industrial applications, the wavelength ranges are mainly defined by the spectral sensitivity of common and affordable detectors.

STEMMER IMAGING is offering so called "pushbroom" hyperspectral imaging systems in the spectral ranges from 400 nm to 1000 nm or 900 nm to 1700 nm. Pushbroom HSI-systems work just like line scan cameras and have the advantage to be used always when parts are moved on a conveyor belt or chutes. Another advantage of the pushbroom technology is the very high spatial and spectral resolution.

Near infrared hyperspectral imaging systems (NIR-HSI) are able to measure chemical properties of samples based on specific absorbance bands caused by N-H, O-H and C-H bondings. Instead of measuring a single point on the sample also the spatial distribution of the chemical properties of the surface of an object is measured.

This information is used for example in sorting systems to separate plastic waste into its different materials, like PET, PVC or PS. This is possible because of a different molecular structure, resulting in different absorbance bands of the multiple types of plastic.

It is also possible to distinguish for example salt from sugar based on the different molecule bondings of the materials – which is obviously not possible by using a monochrome or RGB camera. NIR-HSI systems measure the molecular overtones and combination vibrations of the fundamental vibrations, which are located in the mid-infrared range.

Because a broadband near infrared light source is required, typically industrial halogen illuminations are used in NIR spectroscopy. Since LED illuminations, which combine several NIR LED wavelengths are now available, they are becoming more popular. These illuminations offer a lot of advantages for temperature critical products like cooled or frozen food.

Over the years, STEMMER IMAGING has acquired extensive knowledge about hyperspectral imaging related applications and can help you to find the right components. We also offer evaluations or even complete feasibility studies.

These systems are based on years of research and integration to enable some of the toughest applications to be delivered with lower risk and with less time.