Study On A Grafted Seedlings In-Plug Measurement Method Based On Machine Vision

Application of Grafting Techniques is the most effective method of overcoming continuous cropping disease on the Production System of Facilities Agriculture. In the grafting process, the degree of matching stem diameter size for rootstock and scion have a straight-forward impact on the survival rate of grafted. Thus, this article measures parameters of plug seedling embryo and cotyledon diamoter by the means of binocular vision in the tray, and provides basic data for automatically matching rootstock and scion.The main work of this thesis has several aspects:1. Study on the model of plug seedling. Two kinds of relationship models are studied: the relationship model of seedling diameter and seedling height and the relationship between the seedling stem short axis direction and cotyledon direction. Achieve rhizome measuring system, cotyledon measuring systems and positioning systems. Using binocular vision technology for real-time measurement of complex environments. Verify the reasonableness of the relationship between these two models by experimental data. Experiment shows that Zucchini Seedling Cotyledon in the direction of deviation between 61.23°and 64.65°is short axis of seedling diameter, and long axis of seedling diameter is in the direction of deviation between 151° and 152.241°. What’s more, the seedling diameter from root to shoot tip was decreased, a part of them Occurs that the middle section is relatively thicker than both ends. Draw a conclusion from above : there was no relationship between the diameter and height of the seedlings.2. Study on the separation of the two cotyledon. Based on separation of cotyledon from the people who used contour depth information when he did this project before, then uses Freeman chain code to encode cotyledon edges, gains the midpoint of the predecessor and successor points with equal distance of each chain code, and compute Euclidean distance between the midpoint of the chain code, get candidate inflection point set. The matching method of candidate inflection point and the improvement of the matching precision of the two direction searching strategy are studied. Experiment shows that for 44 detection points, using one-way search algorithm to match the logarithm is 5, but using reverse search algorithm to match the logarithm is all right. Combined with three dimensional depth detection method, making three dimensional coordinate measurement of 1/8 contour chain near matching point, for the two time separation of inflexion mutation difference, further improve the correct rate of cotyledon separation.3.Detection method in the tray. The design of multi camera parallel plate measuring device, put forward the measuring method of the plug seedling disc, continuous collection and measurement of grafted seedlings is done in the measurement area, and the estimation method of the short axis of the seedling diameter of the measurement is given. The growth point was studied by using the turning point and the direction of the growth point on the disc, and the growth point was matched with the feature points of the left and right visual features to obtain the depth information of the growth point.4. Preliminary research on the testing prototype. Prototype is discussed and the preliminary design of the motor, control card, slider component selection and connection, to build the prototype platform study based on visual motor control, write measurement software, to carry out experimental measurements. The experimental results show that the 100 groups of the grafted seedlings with the angle of more than 120 degrees, the seedling and stem to stand upright, the implementation rate of the measuring device is 89%, compared with the manual measurement, the mean value of the measurement error is 0.171 mm.