Fig. 7From: Sky-canopy border length, exposure and thresholding influence accuracy of hemispherical photography for complex plant canopiesa–c Frequency distribution of pixel fraction along the greyness gradient of model CHPs, and d–f estimated gap fraction under different ETM extents. In a–c, grey pixels are those in between the humps of canopy and sky pixels. The figure is derived from CHPs of four model canopies with the same designed gap fraction of 0.25 and SCB length per unit area ranging from 0.05 to 0.4 mm mm−1. Note log scale used on y-axis of panels a–c. The unit of the exposure manipulation, thresholding manipulation and ETM extent is stopBack to article page