What does Emergence Fraction (EF) mean?

1.1.1. Product Description

Some crop types are planted at sufficiently high densities that plants cannot be individually segmented and counted (e.g. wheat, soybean). In these cases, SlantRange employs a subtractive approach that identifies gaps in rows to produce a metric called Emergence Fraction.

Figure 3 below shows a graphical representation of how EF is calculated starting from 1) raw color image (left), 2) the segmentation of growing vegetation from background soils, and 3) the measurement of gap lengths (shown by a red line) along individual rows (right).

Figure 3: Steps in calculating EF in soybeans

A row with zero missing plants has an EF of 100%. A row that is 10 plants long and is missing 1 plant has an EF of 90%, and so on. To estimate population, the planted density is multiplied by EF (e.g. 100,00 planted per acre x EF of 90% = 90,000 plants per acre). This approach is of course subject to any errors in the “as-planted” value.

Figure 4 below shows an example of two soybean plots, one with high emergence fraction and the other with low emergence fraction.

Figure 4: Soybean with 90% emergence (left) and 64% emergence (right)

1.1.2. Reporting Method

Fractional emergence (0 - 1) over selected grid size

1.1.3. Availability

Row crops