Study On The Absorption Of Visible Light By Wheat Grain And Its Application In Photoelectric Detection

Wheat is one of the three major staple food materials in the world and the safety of wheat is related to the safety of people's livelihood.Wheat grains will inevitably suffer from disease infections in the process of production and storage and transportation,such as fungi,mildew and so on,which seriously affect the quality of wheat and its products.Moreover,eating infected wheat and its products will seriously hurt human and animals' health.Therefore,it is very important to identify and detect infected wheat grains in real time and efficiently.In this paper,through the study of the experiment on the absorption of visible light by wheat kernels,and the aim is to obtain the wavelength with the most significant difference in absorption between normal wheat kernels and infected wheat kernels in the visible light range.Apply the light source of this wavelength to photoelectric detection,and complete the development and trial production of the photoelectric detection prototype for infected wheat grains.Finally,study and analyze the prototype,and initially realize the real-time and highefficiency detection of infected wheat kernels.First,The wavelength of the light source selected is(400?950)nm.And separate the light source with 7 filters with a center frequency of(425?725)nm and a bandwidth of 50 nm.After spectroscopy,normal wheat kernels and infected wheat kernels were irradiated to obtain their corresponding 7 absorption rates,and the absorption rate of normal wheat kernels and infected wheat kernels in the(600?700)nm band was significantly different;Then,separate the light source with 5 filters with a center frequency of(610?690)nm and a bandwidth of 20 nm.After splitting,irradiate normal wheat kernels and infected wheat kernels to obtain their corresponding 5 absorption rates.By establishing a fitting curve for analysis,it is concluded that normal wheat kernels and infected wheat kernels have a significant difference in the absorption of 660 nm wavelength light.Second,select an LED light source with a center frequency of 660 nm and a bandwidth of 20 nm.Design the overall plan of the photoelectric detection prototype.According to the absorption rate of the wheat grains to visible light,the light source with the most significant difference in absorption rate was selected and applied to the photoelectric detection prototype;Complete the design of the queuing mechanism and other hardware parts of the wheat kernels,and compile the identification and detection programs of infected wheat kernels,the communication program between the single-chip microcomputer and the touch screen,and the human-computer interaction interface of the touch screen and so on.Finally,add a trap circuit to filter out 50 Hz power frequency interference;Through targeted experiments,it is concluded that the movement speed of the wheat grains,the movement posture of the wheat grains and the light intensity of the light source will all affect the detection accuracy of the prototype;Test the performance of the prototype,and it was concluded that the detection rate of the prototype was 99.5%,and the case rate error was 5%.