Recognition of Fill and Empty Walnuts Using Acoustic Analysis and Fuzzy Logic

Document Type : Research Article


1 Department of Biosystems Engineering, Islamic Azad University,Takestan Branch, Takestan, Iran

2 Department of Biosystems Engineering, Tarbiat Modares University, Tehran, Iran


To increase the amount of export and marketability of walnuts, a quick, cheap and non-destructive sorting approach should be used. The overall objective is to sort the full, half full and empty walnuts relying on fuzzy logic and sound analysis methods. To sort the walnuts the sound processing technique was used. In this regard, effective parameters on sorting and quality such as: size and shape of walnut were studied. For this purpose, 300 dried walnuts were randomly selected from a walnut orchard for use in experiments. An electronic system consisting of a computer, a microphone, and a mechanical section consisting of a sound chamber were designed to measure the sound intensity of a walnut. At this stage, each walnut was released in three directions: back, side and abdomen 30 cm above the surface of the sound chamber. The sounds were recorded by a microphone with acoustic beats on a sound chamber made of wood and a 45-degree slope. The data from the sound signals were stored in the time domain on the computer and then processed by the MATLAB software. In order to eliminate the ambient noise of signals, Kalman filter algorithm was used to achieve high accuracy and fast convergence. Then these data were analyzed by fuzzy logic method. In this research, WEKA software and J48 algorithm have been used to classify walnuts based on their filling and using the features extracted from the walnut collision with a wooden plate. In order to classify walnuts according to the fullness of walnut kernels, a scientific and innovative index called Full Kernel Index (FK) was used.  The results of this study showed that for classification of walnut, decision trees due to simplicity of structure and creation of fuzzy rules and threshold values of membership functions make fuzzy inference system with high accuracy. The final fuzzy model was presented to classify walnut into two classes with 0.087% separation accuracy and 3 classes with 0.080% separation accuracy.


Chatrabnous N, Yazdani N, Vahdati K (2018) Determination of nutritional value and oxidative stability of fresh walnut. Journal of Nuts. 9(1):11-20.
Doosti A, Ghezavati M, Maleki A, Mahmoodi M (2012) Isolation of nuts full of nuts using artificial neural network. 1st National Conference On New Concepts in Agriculture. Islamic Azad University of Saveh.
Ebrahimi A and Vahdati K (2006) Improved success of Persian walnut grafting under environmentally controlled conditions. International Journal of Fruit Science. 6(4): 3-12.
Farhadi M, Abbaspour-Gilandeh Y, Mahmoudi A, Mari Maja J (2020) An integrated system of artificial intelligence and signal processing techniques for the sorting and grading of nuts. Applied Sciences. 10(9), 3315.
Farsi M, Fatahi Moghadam M, Zamani Z, Hassani D (2018) Effects of scion cultivar, rootstock age and hormonal treatment on minigrafting of Persian walnut. International Journal of Horticultural Science and Technology. 5(2), 185-197.
Farsi M, Fatahimoghadam M, Zamani Z, Hassani D, Ahmadi A (2016) The histology of minigrafting of Persian walnut trees cv. Chandler. International Journal of Horticultural Science and Technology. 3(2), 167-177.
 Ghezavati M, Doosti A (2013) Separation of Pistachio Nuts from The Brain by Sound Processing and Neural Networks.7th Engineering and Mechanization. Shiraz University.
 Hajizadeh M, Kasrai M (2014) Walnut Sorting Using Special Mass Vision Machine. 5th National Conference on Agr. Machinary Engineering and Mechanization. Mashhad.
 Hassankhah A, Vahdati K, Rahemi M, Hassani D, Sarikhani Khorami S (2017) Persian walnut phenology: effect of hilling and heat requirements on budbreak and flowering date. International Journal of Horticultural Science and Technology. 4(2), 259-271.
 Heidari L, Boroomand N, Sadat-Hosseini M (2019) The effect of different water potentials on seed germination and growth of some persian walnut populations. Journal of Nuts. 10(2), 186-201.
 I Onaran TC Pearson, Yardimci Y, Cetin AE (2006) Detection of underdeveloped hazelnuts from fully developed nuts by impact acoustics. Transactions of The Asabe. 49(6), 1971–1976.
 Ivani A, Minae S (2008) Volume measurement based on stationary waves of Helmholtz resonator. Iranian Journal of Agricultural Sciences. 38(3), 219-226.
 Khakrangin R., Mohammadzamani D., Masoodi H (2015) Design and Construction of Non-Destructive Walnut Quality Measurement System Using Fuzzy Logic. M.Sc., Islamic Azad University, Takestan Branch.
 Khalesi S, Mahmoudi A, Hosainpour A, Alipour A (2012) Detection of Walnut Varieties Using Impact Acoustics and Artificial. Neural Networks (ANNs). Modern Applied Science. 6(1), 43-49.
 Khalif S, Komarizadeh MH, Tous B, Nikbakht AM (2011) An intelligent system for sorting walnuts based on acoustic emission and neural network. Journal of Food, Agriculture & Environment. 9(1), 109 – 112
 Khalifa S, Komarizadeh MH (2012) An intelligent approach based on adaptive neuro-fuzzy inference systems (ANFIS) for walnut sorting. Australian Journal of Crop Science. 6(2),183-187
 Korol T (2012) Fuzzy Logic in Financial Management. Fuzzy Logic-Emerging Technologies and Applications.  Elmer P. Dadios, IntechOpen.
 Kurtulmuş F, Öztüfekçi S, Kavdır İ (2018) Classification of chestnuts according to moisture levels using impact sound analysis and machine learning. Food Measure. 12, 2819–2834.
 Naderi-Gargari S, Abbaspour-Gilandeh Y, Rasooli-Sharabiani V (2017) Design and construction of real time sorting and grading machine of hazelnut using acoustic signal processing method. In: 1st International and 5th National Conference on Organic vs. Conventional Agriculture, 16-17 August 2017, Ardabil, Iran.
 Omid M, Mahmoodi M, Akbari A, Akram A (2010) An ANN and Acoustic-Based Machine for sorting pistachio nuts, Journal of Agricultural Engineering Research. 10(4), 13-24.
 Omid M., Mahmoudi A, Omid MH (2010) Development of pistachio sorting system using principal component analysis (PCA) assisted artificial neural network (ANN) of impact acoustics. Expert Systems with Applications. 37(10), 7205–7212.
 Rajabi M, Ghanbari A, Labafi R (2011) Evaluation of two neural and fuzzy models to predict grain loss losses at the combine platform site at different harvest times. 7th National Conference on Agr. Machinery Engineering and Mechanization. Shiraz University.
 Raoufi A, Vahdati K, Karimi S, Roozban M (2020) Optimizing seed germination and growth of seedlings in Persian walnut. Journal of Nuts. 11(3), 185-193.
Sarikhani S, Vahdati K, Ligterink W (2021) Biochemical properties of superior persian walnut genotypes originated from southwest of Iran. International Journal of Horticultural Science and Technology. 8(1), 13-24.
Thapa R, Thapa P, Ahamad K, Vahdati K (2021) Effect of grafting methods and dates on the graft take rate of Persian walnut in open field condition. International Journal of Horticultural Science and Technology. 8(2), 133-47