A Refined Measurement Technique for Cereal Quality Assessment

Abstract

The determination of the quality of a grain, say, rice or wheat, is generally considered as a difficult measurement parameter. However, in this method, this quality has been traced to the value of the capacitance in a cell packed with the grains. Such small capacitance values are not easily measurable in presence of a large parallel conductance, which is due to absorbed and inherent water content. Further, there is also a non-linearity in the ionic conductance part. Since the capacitance alone has to be isolated for assessing the quality, the problem is that of a measurement of a small value of capacitance which is in parallel with a high nonlinear ionic conductance. This paper describes the use of a suitable transformer ratio arm bridge. The data processing is done by digital signal processing. The non-linearity problem was solved by using digital quadrature detection of the bridge signal along with the use of Hilbert Transform. The method is explained and results are shown to be repetitive and decisive in assessing the quality of cereals.

Indexing terms:

• Moisture in cereals
• Non-linear conductance
• Hilbert transform
• Digital phase sensitive detection
• Transformer ratio arm bridge
• Quality of grains

Additional information

Notes on contributors

S Ananthi

S Ananthi was born in Thalainayar Village, Tanjavoor District of Tamil Nadu on 1st May 1958. She joined the Central Instrumentation Department of the Madras University in 1980 and is presently Lecturer in Instrumentation Engg. She took her MTech Degree from IISc, Bangalore and her PhD from the Madras University. Dr Ananthi published number of articles in 'Electronics for You Magazine during 1982–2000. She has presented eleven papers in International Conferences during 1994–2000. She is the author of two books: One on Microprocessors and another on Digital Signal Processing. She has contributed in the field of Gabor Transforms applied to Medical Ultrasound diagnostics and in NMR Signals from Chemicals in NMR Spectrometry.