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

Figure 6

Steps of seeding absence detection during seed drill operation based on 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.

(a)

(b)

(c)

(d)

(e)

(f)

(g)

(h)