Apple Moldy Core Detection Method And Equipment Based On Dual Transmission Band

Apple industry is one of the most important fruit pillar industries in our country. The action of prevention and cure of apple moldy core is weak, which makes a huge loss of apple economic, meanwhile, affects the quality of apple and export rateseriously. With the development of nondestructive detection technology of fruit gradually, more and more attention is paid on apple moldy core nondestructive detection, in which the VIS/NIR detection technology has been become the one of the most important methods. Through the observation of the existing apple moldy core detection systems,it is found that most detection systems utilizea full band spectrometer to acquire corresponding spectrum and do analyze.It is also found that these systems have many limitations such as thehigh usage cost and the poor on-sit testing that couldn’t adapt to requirements of the disease researchers toscreening of samples and the apple vendors to detectapplesrapid on-site.Therefore, this paper aimed at the application requirements of theportablenondestructive apple moldy coredetection equipment,proposed a detection method by dualtransmission band and photoelectric sensor based on the spectral transmissiontheory. The equipment proposed in this paper is designed based on adual transmission band which is extremely related to apple moldy core. MSP430 is adopted in the nondestructiveequipment as the core processor, which embed the tow classifiers LDA model of apple moldy core. It implement the rapid precise detection of apple moldy core.The main research contents and conclusions of this paper are as follows:(1) First, a spectrum transmission detection platform of apple moldy core isbuilt and a criterion of apples moldy core grade classification is proposed. A series of experiment to acquire and analyze apple moldy core transmission spectrums is set up. Correlation analysis method is adopted to extract the apple moldy core characteristic bands, which shows thatthe transmission spectrum intensity on 709.36 nm become weaker with the apple disease level increasing. In order to eliminate the influences of apples internal quality(sugar degree, firmness) and diameter to transmission intensity, the reference band is extracted by the correlation analysis and the wavelength is 779.54 nm.(2) Dual band narrow-band led light source combined with photoelectric sensor for the apple moldy core detecting isdesigned in this paper. The detection equipment use the MSP430 as the core to achieve theapple moldy core accurate detect. The design of this equipment can be mainly divided into three modules, which are exterior design, circuit module design and dual band transmission light source design. The light sourcesutilizetow narrowband LEDs, ofwhich the center wavelengthsare 710 nm and 780 nm independently. Under the high voltage PWM control mode, the single lamp luminous efficiency increases 3 times compare to constant-current mode. It’s provides a basis for the dual band light source optimal design.(3) A LDA-based apple moldy core discriminant model is established. The apple transmission intensity data and disease grade data are obtained by the dual band detection equipment. Different discriminant analysis are performed withsix classification categories, threecategories and two categories respectively by LDA. The results show that the discriminant accuracies increases with the classification categories decreases.A disease level definition for three-categorysamples is based on whether the samples are infected by moldy core(grade 1), rot(grade 2)or not(grade 0).The analysis results show that the grade 1apple discrimination accuracy rate is 57.1 and the grade 2 is 70%. It is prove that the equipment to divide the grade of apple moldy core is possible. According to the analysis results of the three models, the equipment adapt the 2-level discrimination model which the overall accuracy rate is 88.2% while the accuracy rate of disease is 87.1%.(4) The performance test of dual band apple moldy core detection equipment has been done by the 49 same batch apple samples. The results showed that the accuracy rate of the device is 89.8% while the accuracy of disease apple is 87.5%. This is prove that the detection equipment has a good ability to distinguish the apple moldy core. Meanwhile the performance index of the device electrical parameters were measured. The detection time of one single <1s and the device can continue working 33.3h.It’s shows that the device could achieve high detection performance and provided a guarantee for apple moldy core rapid and stable detection.In a conclusion, the method based on dual transmission characteristic bandsopens a new world of apple moldy core nondestructive detection. The dual band apple moldy core detection equipment meets the requirements of research samples and apple vendors the high quality apple screening. It is very practical significance for promoting the level of high quality apple classification and beneficial toapple export industry.