IEEE Geoscience and Remote Sensing Magazine - March 2021 - 204

204

IEEE GEOSCIENCE AND REMOTE SENSING MAGAZINE

MARCH 2021

Sick
LMS4002000

Lidar

PlantExplorer

Fluorescence
sensor

Stereolabs
ZED

LI-COR
6400

Photosynthesis
sensor

Stereo camera

MODEL

SENSOR TYPE

Ear density, grain number
and size, FAPAR, crop
dynamic monitoring,
phenology, canopy coverage,
canopy height, leaf rolling,
leaf angle, lodging, biomass,
canopy structure, weed
infestation, yield
GAI, ear density, grain
number and size, FAPAR,
crop dynamic monitoring,
phenology, canopy coverage,
canopy height, leaf rolling,
leaf angle, lodging, biomass,
canopy structure, weed
infestation, yield

Active sensor
that detects
the distance to
a target from
pulses of laser
light

33 Light source: visible red light
(650 nm)
33 Laser class: 2
33 Aperture angle:
horizontal 70°
33 Scanning frequency:
230-500 Hz
33 Angular resolution: 0.1-1
33 Working range: 0.7-3 m

Plant diseases and pests,
lodging, chlorophyll fluorescence, photosynthetic status,
biomass, grain quality, light
use efficiency, nitrogen use
efficiency, nitrogen nutrition
index, yield

Camera with
two or more
lenses, with a
separate image
sensor for each
lens

Passive or active sensor at
the ultraviolet,
visible, and
near-infrared
spectral regions

33 Sensor type: charge-coupled device
33 Image resolution: 1.3
megapixels
33 Spectral range: 350-1,000
nm
33 Frame rate: 20 images per
second

Plant diseases and pests,
lodging, chlorophyll fluorescence, photosynthetic status,
biomass, water use efficiency,
light use efficiency, nitrogen
use efficiency, nitrogen nutrition index, yield

PHENOTYPING TRAITS

33 Sensor resolution: dual
4-megapixel sensors with
2-µm pixels
33 Sensor format: native 16:9
format for a greater horizontal field of view
33 Sensor size: 1/3-in backside
illumination sensors with
high low-light sensitivity

Passive sensor
at the visible
spectral region

DETAILS

33 Sensor type: absolute,
open-path, nondispersive
infrared gas analyzer
33 Bandwidth: 10 Hz
33 Range: 0-3,100 µmol mol -1

SENSOR PARAMETERS

Controlled environment; field

Controlled
environment; field

IMAGING
ENVIRONMENT

TABLE 2. COMPARISON AND LIMITATIONS OF DIFFERENT SENSORS FOR FIELD CROP PHENOTYPING TRAITS.

Laser imaging

3D imaging

Fluorescence
imaging

IMAGING
TECHNIQUES

Continued

33 Sensitive to small differences in
path length.
33 High cost of the sensor.
33 Sensor should be integrated
with GPS for georeferencing
information.
33 Data processing is time
consuming.

33 Experimental conditions influence its performance.
33 Resolution of images is lower.
33 Field application is limited.
33 Sensor needs calibration
before use.

33 Difficult to measure at the
canopy scale due to low signalto-noise ratio.
33 Difficult to implement on field
crop phenotyping platforms.
33 It will be strongly influenced by
background noise.

33 Sensors are costly.
33 Measurements are time consuming.
33 Only measured point data are
obtained.
33 It is not easy to measure at the
canopy scale.
33 No image.
33 It is not possible to mount
on field crop phenotyping
platforms.

LIMITATIONS

IEEE Geoscience and Remote Sensing Magazine - March 2021

Table of Contents for the Digital Edition of IEEE Geoscience and Remote Sensing Magazine - March 2021