Tree Canopy Size and Density Assessment with a Laser Scanner Citrus Research and Education Center Masoud Salyani and J. Brian Wei 2 nd Workshop on Precision Agriculture for Florida Citrus January 21, 2004

Citrus grove with dead trees and resets

Spray drift

Ultrasonic sensors

Photocells

Laser sensor

CREC Laser system in operation

Scanning system principle

Scan profile

Schematic view of a Distance image i+1+ ΔW XLXL XRXR YBYB YTYT j j+1 i Illustrated in next slide (1,1) x y

Pseudo-color image of a tree

Spatial resolution test A HIJK LM B A HIJK LM BCD EFG C D E F G

A HIJK LM BCDE F G Not continuous Continuous image lines Distance image for vertical targets (horizontal resolution)

A HIJK LM B C D E F G Not continuous Continuous Distance image for horizontal targets (Vertical resolution)

A HIJK LM BCDEFG White Black Signal amplitude image for vertical targets

Ground truth of length measurements in three dimensions

Std. dev. Manual vs. laser length measurements

Picture of a test tree

Signal amplitude image

Distance image

Inverted distance image

Smoothing of canopy boundary Figure 2: Scanning illustration and canopy boundary smoothing Ground L ij L ij+1 LL ij+1 LL ij Ө Sensor Smoothed canopy Original canopy HsHs β D Deep gap Shallow gap Through hole

Peak-link algorithm

Distance image – smoothed by peak-link algorithm

D 1a D 2a HaHa HbHb HdHd HcHc Ground Level D 2c D 1c D 1b D 2b Tree Canopy Manual Volume Measurement

Manual- and laser-measured volumes Std. dev.

Canopy volume at different heights of trees

Visual vs. laser-measured densities

Corr. bet. Visual and laser-measured densities

Foliage density at north and south sides of trees Std. dev.

Foliage density at different tree heights

User Interface

Amplitude image of one row Processed canopy image of the row

Real-time measurements of one row

Real-time run, 1 mph

Real-time run, 3 mph

Thank you