A Preliminary Study of Seeding Absence Detection Method for Drills on the Soil Surface of Cropland Based on Ultrasonic Wave without Soil Disturbance

Figure 5

Steps of seeding absence detection during the seed drill operation based on the energy circle when : (a) step 1, (b) step 2, (c) step 3, (d) step 4, (e) step 5, (f) step 6, (g) step 7, and (h) step 8.

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