Research On The Cracked Eggs Detecting System Based On SCM

Getting rid of cracked eggs is an important work in foods processing. The method of detecting cracked eggs is mainly by hand at present in China, which is not only high labour intensity,but also the low efficiency and poor precision.So it is essential and significative to develop a detecting system of eliminating the cracked eggs roboticizedly.In this paper, a detecting cracked eggs system was designed based on SCM. The system contains the following modules: sound collecting, signal amplifying, band-passed filtering, anology to digital conversion, serial port communication and automatic classification circuits. Using the system, we could collect the sound signals of knocking eggshells and transfer them to personal computer.Based on the digital signal processing technology and MATLAB, a large numbers of datum were analyzed throught power spectral. By this means we could find out the differences between the intact egg's sound signals and the cracked egg's in the frequency field, and then regarded their average and extreme difference of the power spectral area as the discriminant vectors, at last we established the following discriminant function of the two sound signals based on the principle of "Bayes" discriminant:G_h = -0.73870x₁+ 0.02314x₂ + 33.01895x₃ -10.65950x₄ -144.68168 G_s= -0.59691x₁+ 0.09112x₂+31.22730x₃ -10.26062x₄ -102.99508 We programmed the procedure of detecting cracked eggs based on SCM with C51 language. The system software includes the main program and interrupt service program. In the main program, the SCM is always waiting for knocking eggs. Once the knock happened, the program entered the interrupt service program, in which the system began to sample, storage and process the signals of knocking eggshells, at last sent the results to the classification institution.The most important character of the system is that it started to sample signals once a egg was knocked. For some limits in main frequency and data bits of SCM, the system is a little deficient in processing speed and precision.