The foundation of Material Sensing as we know it is called spectroscopy. It enables us to identify and quantify materials and their composition with minimal effort.
In this article we will explain to you which steps are necessary to conduct a spectroscopic measurement and successfully identify materials. We hope it will give you a better understanding of Material Sensing and the underlying principles of spectroscopy.
Step 1 - The illumination of a sample
In spectroscopy, a sample is illuminated with a light source. A common lightbulb, as shown in the illustration, emits mostly visible light. But there is also light that cannot be seen by the naked eye. For example, our technology is based on the analysis of near infrared light.
Step 2 - The reflection and absorption of incoming light
The light is then either absorbed, transmitted, or reflected by the object. As you can see in the illustration, not all of the light rays are being reflected by the sample, some of the light is always absorbed.
When using spectroscopy, we differentiate between transmission and reflection spectroscopy. In transmission measurements, the light transmitted through the sample is detected. In reflection measurements, the light hits the sample and is reflected, as is done with our SenoCorder Solid. When conducting measurements of liquids, a glass cuvette can be used.
Step 3 - The detection of transmitted and reflected light
The reflected and transmitted light contains information about the sample’s material composition. This is because the intensity of the incoming light is changed through the interaction with the object. The information gathered is also referred to as the “optical fingerprint”, unique for each material.
To record the optical fingerprint, it needs to be detected and converted into electrical signals. This process is shown in the illustration with the sensor receiving the information and converting it into a spectrum, available in digital form for later analysis
Step 4 - The identification and quantification of materials
The recorded fingerprints are interpreted by relevant software algorithms and used to either identify or quantify the material. A good example is the identification of textiles e.g., differentiating between cotton and polyester. A good example of a quantitative result would be the amount of cotton in a mixture of cotton and polyester.
Material Sensing opens up many possibilities for potential applications and use cases. If you would like to learn more about the underlying technology, you can head to our blog post “How playing a guitar teaches us about spectroscopy”. The article explains the meaning of wavelengths and the mechanics of spectroscopy.
Which materials would you like to analyze? Download our summary to receive further information on easy-to-conduct textile analysis.