Image processing outside the visible spectrum


The human eye can detect light with wavelengths of approximately 400 to 750 nanometers. For many years, industrial image processing systems focused almost exclusively on this visible range. Due to the increasing performance of sensors in the short-wave infrared (SWIR) and ultraviolet (UV) ranges, the economical use of special cameras outside the visible spectrum is now also possible in applications predestined for this.

Inspection with SWIR cameras is already a proven technology in a wide range of industrial sectors. The new SWIR cameras from SVS-Vistek are able to cover the range visible to the human eye with a single sensor in addition to the SWIR range. The combined use of the visible and SWIR ranges makes it possible, for example, to more easily detect contamination as well as rot or pressure marks on fruits or vegetables on the selection mat, to inspect silicon in the solar and electronics or to identify invisible impurities. , water or steam with other technologies. Requiring only one sensor for the entire wavelength range from 400 nm to 1700 nm results in significantly lower costs and less complex inspection systems.

With the SWIR cameras exo990, fxo990 and exo991, SVS-Vistek currently offers three powerful models in its range. With a resolution of 0.3 MP or 1.3 MP, frame rates of 90 to 259 fps, a very compact sensor format with a diagonal of only 8.2 mm or 4.1 mm, excellent handling of temperature and modern interfaces such as GigE Vision and CoaXPress-12, a wide range of applications can be implemented. The camera offers excellent image homogeneity over the entire spectrum from 400 to 1700 nm. The technical basis is Sony’s SenSWIR sensors, which are currently unrivaled in the market in this quality. A significant improvement over previous SWIR sensors is the so-called Cu-Cu bond, which enables smaller pixel structures and thus improved resolution. State-of-the-art InGaAs technology, high resolution and sensitivity over a wide spectral range are the basis of SVS-Vistek’s industrial SWIR cameras.

New to the short end of the spectrum

The use of ultraviolet wavelengths, which fall within the spectrum of approximately 200-400 nm, has been less popular in industrial inspection than the use of SWIR cameras due to the low resolution of UV cameras previously. available. With the new fxo487MCX and fxo487MXGE UV cameras, SVS-Vistek fundamentally changes this situation. The 8.1MP Sony sensor built into these cameras can detect invisible product defects with ultra-sharp, high-resolution UV images. The most important areas of application for these cameras equipped with a CoaXPress-12 or 10GigE interface are complex inspection tasks, e.g. in the battery, semiconductor, glass, recycling, stone industries precious and automobile.

Polarizing cameras

Another area of ​​interest for industrial inspection is that of polarization cameras. Here too, a sensor developed by Sony forms the basis of this innovative technology. The IMX264MZR, IMX250MZR and IMX253MZR polarized sensors work with an array of polarizing filters of different orientation (0°, 90°, 45° and 135°), which is applied directly to the sensor in each 2×2 pixel array. This configuration has the advantage that with a single acquisition – without changing the illuminance – the degree of polarization of the light, its direction of polarization and the intensity of the polarized light can be measured and evaluated simultaneously. Simultaneous detection of different directions and degrees of polarization enables reliable image evaluation on an optical basis. There is no need to change any mechanical or optical lens or lighting settings, simplifying many image processing tasks.

Based on these innovative sensors, SVS-Vistek currently offers six polarized models of the EXO series with 5 or 12 megapixel resolution and frame rates of 10 to 75 fps. When it comes to interfaces, users can choose between Gigabit Ethernet and USB3. With these polarized cameras, SVS-Vistek opens up exciting new possibilities compared to conventional industrial cameras. The polarization measurement allows, for example, the inspection of non-metallic transparent or reflective materials such as water, plastic or glass, as well as the inspection of difficult surfaces or the reading of black letters on a black background, this which was previously an almost impossible task. task in the production of tires, among others. In the pharmaceutical industry, polarization cameras are particularly suitable for blister inspection in order to reliably detect and sort defective packages or tablet assemblies.

With a wide range of SWIR, UV and polarized cameras as well as perfectly matched lighting and optical components, SVS-Vistek once again demonstrates its technical expertise in industrial image processing, even outside the light spectrum. visible and will gladly advise users on selecting the optimal combination for the task at hand.


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