Abstract: The external quality attributes of fruits and vegetables detected by reflection do not bring sufficient information about the presence of internal diseases and defects, chemical composition, degree of maturity etc. That is why the problem how to be seen, observed and known the internal status of those objects without destruction of the layer (i. e. skin or peel) that protects them from damaging effects of the environment has always been a topical one.
The Project NIQAT funded by the European Commission was directed to solution of this problem with potatoes, apples and peaches assessment based on the method â Seeing Through Layersâ (STL) created by G. Krivoshiev in 1996.
The STL is a method for non-destructive measurement of the internal (i.e. of the fruit flesh) optical density eliminating the disturbing spectrum of the peel by means of diffuse reflectance. As this is equal to a virtual removal of the skin (peeling), the photometric camera implementing the STL method was named V-(virtual) camera.
Here is presented a variant of V-camera as a part of the conveyor system for potato tubers sorting â NIQAT. There are also given mathematical models and results of non-destructive determination of the internal optical density and classification of potatoes in real time, as well as some basic technical parameters of NIQAT system. sundybg.com
Abstract: In practice the collecting of the educational data for a opto-electronic system is a long process. When it is about collecting data for seasonal production, the process itself becomes seasonal. But if the system which scans the production doesnât function properly, we have two alternatives â to stop the measurement and to correct the system, thus we are missing the season and we are waiting for the next one or we can analyze the problem and decide whether the data could be processed later without any loss of information. This publication examines the exact same problem in Lock-In amplifier of the NIR system.
Abstract: Part of results received from several years work upon the instrumental qualification and automatic sorting of fruit and vegetables in Bulgaria by color, maturity and presence of defects are presented. The difference of the optical density is used to characterize the maturity of peaches, apricots, pears, plums, strawberries, tomatoes and pepper. The maturity of green peas is determined by transmittance into the entire peas in spectral parts from
the NIR region. Sorting machines are developed for tomatoes and peaches according to their external and internal color and also potato sorters according to the presence and size of defects both on the peel and in the fruit flesh. An original method is developed to eliminate the skin influence and for precise sorting only by internal defects.
The method is applied for potato tubers sorting in a flow.
Abstract: It has been studied 628 potato tubers taken from different European regions.
The screening group of potatoes includes 20 varieties, every one of which is characterized by its own specific type of skin and flesh. The samples themselves are scanned in the process of gravitation falling during their passage through the measuring zone of photometric camera, developed for the assessment of potatoes being in flow (on-line).
Each sample (individual tuber) was scanned both unpeeled and physically peeled. During this process organoleptic evaluation was made of the appearance and internal quality of the sample.
On the basis of obtained data it has been optimized the mathematic statistical models for prediction of the internal optical density, by which models the virtual peeling is performed.
It has been made a classification (unpeeled, physically peeled and virtually peeled tubers) by using the K-nearest neighbors (KNN) method, by which it has been proven
the a priori, intuitional expectations:
- The spectrum of the samples skin is a disturbing factor and the elimination of its influence is going to increase the precision of potatoes sorting.
- By the method âSeeing through layersâ it is carried out a more precise sorting of potatoes on the basis of the elimination of the skin disturbing effect.
Abstract: The main goal of dissertation is to apply "See Through Layers" (STL) method in optoelectronic system for precise sorting of potato tubers according to the availability and the degree of internal diseases and defects.
Chapter 1 - A literary review aiming at the quality evaluation of some fruits and vegetables with NIR spectroscopy;
Chapter 2 - Determination of the internal transmittance of the potatoes by spectrometer;
Chapter 3 - Application of STL-method for sorting of the potatoes in on-line;
Chapter 4 - Testing of the optoelectronic system NIQAT01LAB in conditions close to the industrial practical process.
