Evaluation Of Rice Thickness And Grain Plumpness Based On Binocular Vision

Rice is a very important food crop for human beings.The grain plumpness of paddy is closely related to the rice yield,and the rice quality evaluation after shelling is also an indispensable part.At present,in the process of rice quality evaluation,only the length,width and other size parameters of rice are measured.Limited by the difficulty of measurement and the lack of technology,there is no extraction of rice thickness.In the process of rice seed testing,the evaluation of plumpness is lack of detailed and effective evaluation indexes.The evaluation process mostly depends on artificial experience judgment,and there is no quantitative standard.In view of the above difficulties and problems,the research carried out in this paper includes:（1）Based on the principle of binocular vision,the binocular images of rice were taken,and the direct thickness measurement target was transformed into the indirect edge height measurement through the hypothetical relationship between the edge height of rice and its thickness.We proposed a matching algorithm based on the edge features of rice to complete the matching of the corresponding points on the edge,which solves the matching problems due to the shape similarity of rice and the lack of surface texture,and makes the automatic measurement of rice thickness possible.（2）In the experiment of 25 kinds of rice and grain samples,all of the measurement errors were within the upper limit of 0.1mm specified in the national standard,and the efficiency was increased by about 17 times compared with manual measurement,which shows the effectiveness and universality of the thickness measurement algorithm we proposed for rice and grains.It is also found that when the number of measured samples is 10 and the small base-height ratio is selected,it is more conducive to the measurement of thickness.（3）On the basis of thickness measurement,this paper studies the evaluation of grain plumpness.By combining the grain thickness threshold with the grain index of yellowness(GI_yellow)proposed in this paper,the"empty grain ratio"was calculated with the accuracy of 90.1%by distinguishing the empty grains and the solid grains from the two levels of shape and color.Then the grain filling index（GFI）was calculated according to the approximate volume ratio of rice and grain to further distinguish the full grains and the shriveled grains among the solid grains,and the"shriveled grain ratio"and"average filling index of full grain"were obtained.Finally,three evaluation indexes of empty grain ratio,shriveled grain ratio and average filling index of full grain were obtained.（4）Based on the above three evaluation indexes,the three grades of grain plumpness:hollow type,medium type and full type,were predicted using support vector machine.Compared with the results of artificial evaluation,the accuracy of plumpness evaluation of 60 kinds of grains is about 83.3%,which proves the validity of the three evaluation indexes and realizes the quantitative evaluation of grain plumpness.The rice thickness measurement and grain plumpness evaluation in this paper can provide effective technical support for rice quality evaluation and rice seed testing process.