Mininfra instruments are scanning spectrophotometers operating in the Near Infrared (NIR) wavelength range. Mininfra grain analysers are transmission mode (NIT – Near Infrared Transmission) instruments that apply light of 780-1064nm wavelength for the measurement because grains and flour transmit this type of light in a measurable extent. The instrument trans-illuminates the material to be analysed and measures the intensity (spectrum) of the transmitted light at several wavelengths. The measurement of the spectrum is done at some selected wavelengths: the light of these wavelengths are produced by a so called grating monochromator.
Based on the measured intensities of the transmitted light the built-in computer calculates and displays the characteristics of the analysed material. Before the analysis we have to determinate the mathematical correlation between the spectrum of the transmitted light and the component to be measured in advance – this correlation is called calibration. For each product and component different calibrations are needed. Developing a new calibration requires the measurement of the spectra of a large number of samples analysed with ‘traditional’ methods in laboratory. We calculate the calibrations based on these spectra. The instruments can only measure a component of a product after installing the relevant calibration.