Wide product variety, high manufacturing speed and quality requirements in the processing industry calls for a flexible solution that can transfer from one product to another, and reliably identify materials based on biological, chemical and physical parameters. Hyperspectral imaging plays an important role where traditional color, spectral or x-ray cameras cannot provide a full solution.
Perform thorough measurements with perfect hygiene: the non-invasive technology gives results without touching the goods. Reach 100% inspection coverage, fully imaging every product. Detect contamination or foreign objects, moisture, chemical composition, or color with unmatched accuracy and detail, improving quality and reducing waste and costs.
Case example: Measuring crust color with hyperspectral imaging
The hyperspectral camera is well suited for color measurements, since it is more accurate than RGB cameras and, unlike visual inspection, completely objective. It is possible to define the target’s absolute color in Lab color space with the accuracy of ∆E<1 which is better than human color perception (∆E=1), or its relative color in relation to another target as accurately as ∆E=0.2.
In the baking industry, it is possible to determine the exact crust color and adjust the baking process to improve the product quality. This will lead to a reduced amount of waste and, as a result, reduced cost. Push-broom technology makes it possible to measure every point of the target, which ensures that the product is not unevenly baked. What is more, the single line of measurement used with the push-broom method requires that only the measurement line needs to be illuminated, which reduces the amount of lighting needed.
To test the suitability of hyperspectral imaging in the baking industry, we measured buns with different baking times and crust color. Our test results demonstrated that baking time affected the Lab color values. The L-values, which measure the lightness/darkness, diminished as the baking times increased. The overcooked buns also had clearly lower b-values than others.
From these results, it is quite simple to determine acceptance limits for baked goods that helps not only to sort the products based on quality but also to adjust the baking process to achieve the best results.
We have developed hyperspectral cameras specifically for industrial and production line use. They are small and lightweight, fast, and reliable, and the standard interfaces make it possible to integrate them to existing solutions.
Our products are called push-broom, or line-devices – they collect the full spectral and image information with single image. The final datacube is formed by scanning the target line-by-line. This is why you only need to illuminate that one single line where the data is collected.
Current main competing technologies are tunable filter and variable filter instruments. With tunable filter, one wavelength band is measured from two-dimensional area at a time. With linear variable filter, all wavelength bands are measured simultaneously but each band from different position on the target area.
Compared to push-broom, both tunable filter and variable filter technologies require homogenous and stable illumination for much wider two-dimensional area. They also struggle in getting co-registered spectrum, which leads to difficulties in data processing, unreliable spectral signatures and delayed processing results.
It is reasonable to conclude that only line imaging push-broom HSI is suitable to all industrial on-line applications where moving and changing targets are measured, and spectral co-registration is required.
Specim FX cameras
Specim FX series cameras are small, fast and affordable. We have designed them specifically for industrial machine vision applications, and several versions operating on different wavelengths means that you can find a camera to meet your specific needs. Get reliable results with less light and high framerate.
In our case examples, we used FX10C and FX17 cameras. FX10C operates on visible light area and is optimized for color measurement. It is an ideal option for anyone who is looking to measure and analyze the crust color in bakery products, while FX17 is at its best when collecting data for material identification, meaning chemical composition analysis, or moisture or foreign object detection.