Study On Quality Evaluation Method Of Shawo Radish Based On Ultrasonic Texting

Tianjin Shawo radish as a kind of fruit and vegetable products is widely popular, and it has a high reputation both at the home and abroad. At present, people divided the quality grade of the Shawo radish by external quality index. As we know, ultrasonic nondestructive testing technology has a lot of advantages. In this paper, an ultrasonic nondestructive testing technology is proposed to detect the internal quality about Shawo radish. Because the hollowness is the mainly disease about Shawo radish, so this article is mainly aimed at detect the existence of hollowness about the radish. The main work and achievements have completed are the following:(1) Summarized the present situation about detection of fruit and vegetable products internal quality. And introduces the results of the scholars use ultrasonic testing at home and abroad. Illustrates the feasibility of using ultrasonic testing to detect the internal quality about the Shawo radish. In addition, design the corresponding experiment scheme.(2) Design a set of ultrasonic testing platform based on the experiment scheme. The detection platform was designed of semi-circular arc, so that it can satisfy the requirements that two detection probe between the range of 0～180 DEG at an arbitrary angle. As the same time, it can meet the detection of measured objects of different shape and size. In addition to the detection probe intact clamping, so as to ensure that the probe and the measured object contact condition.(3) Analyzed the relationship between the physical parameters with the degree of hollowness.Through the analysis, there is no linear relationship between ultrasonic velocities with hollowness, and no significant effect with the sample weight, diameter and so on. The received ultrasonic wave patterns were analyzed from the time domain signal and the frequency domain signal. By analyzing the time domain signal of the graph, the amplitude of hollowness Shawo radish less than non-hollowness, and the waveform about the hollowness is incomplete. Beside, through the analysis of the signal spectrum, which obtained by Fast Fourier transforms(FFT) of the ultrasonic, the most of the maximum amplitude spectrum value of hollowness less than 18, and the non-hollowness greater than 18. So, the hollowness of Shawo radish can be effectively identified based on the maximum amplitude value of the spectrum.(4) About the above conclusion, the results are verified by using randomly selected samples. By comparing the prediction and actual situation of Shawo radish, the method for accurate rate of non-hollowness and hollowness were 81.25% and 75% discriminant.Therefore, put forward the preliminary implementation Shawo radish internal quality grades of ideas.