Optical Farming

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OPTICAL FARMING
ISP,CUSAT
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Why farming?

• Prime requirement for survival.
• Civilization began with agriculture.
• Backbone of national economy.
• Important in industrial development.
• Important in International Trade
• Provide occupation in large scale. 

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World Top 10 - Agriculture Exporters Countries
Country United States France Netherlands Germany U
nited Kingdom Canada Australia Italy Belgium Spain
In Million Dollars 42,826 24,262 19,780 13,842 11,
613 10,107 9,824 9,446 9,013 6,621
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Importance of technology in agriculture

• To eliminate dependency over weather for farming.
• To increase yield.
• To reduce time period of production.
• To decrease labor.
• To get high quality of food.
• To decrease production cost simultaneously.
• To get safe and secure food.

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Issues - What is being measured?

• Variability in light source
• Filtering of light along path
• Measuring units/calibration of sensing system
• Geometry
• Spatial and temporal frequency of measurements

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Spectral signature

• Electromagnetic energy reaching the earth's
  surface from the Sun is reflected, transmitted or
  absorbed.
• Specific targets have an individual and
  characteristic manner of interacting with
  incident radiation that is described by the
  spectral response of that target.
• The spectral response of a target also depends
  upon such factors as
• the orientation of the Sun,
• the height of the Sun in the sky (solar elevation
  angle),
• direction in which the sensor is pointing
  relative to nadir (the look angle),
• the topographic position of the target in terms
  of slope orientation,
• the state of health of vegetation if that is the
  target,
• and the state of the atmosphere,
• time of observation.

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Spectral Characteristics of Soil
The spectral reflectance of soil is controlled,
for the most part, by six variables a) Moisture
content b) Organic matter content c) Particle
size distribution d) Iron oxide content e) Soil
mineralogy f) Soil structure Of these
variables, moisture content is the most important
due to its dynamic nature and large overall
impact on soil reflectance.
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Variation in the spectral reflectance
characteristics of vegetation according to leaf
moisture content.
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Soil Analysis
Sensor used

• Electromagnetic
• Optical
• Mechanical
• Electrochemical
• Airflow
• Acoustic

Electromagnetic Sensors Electromagnetic
techniques include methods that are dependent on
the effect of moisture on the electrical
properties of soil. Soil resistivity depends on
moisture content, hence it can serve as the basis
of sensor.
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Some new photonic technology in soil analysis
Jan Kleissl of the University of California, San
Diego, developed a method of measuring the
sensible heat flux in agricultural fields using
laser scintillation. Originally developed for
military application, Kleissls method infers how
much heat is emitted from the scintillation
observed. The sensible heat flux is inversely
proportional to evapotranspiration, Kleissl
says. The more available soil moisture, the more
evapotranspiration.
Optical Soil Dipstick Its a Tel Aviv University
invention and it has various application. soil
dipstick will help scientists, urban planners and
farmers understand the changing health of the
soil, as well as its agricultural potential and
other associated concerns. The thin catheter-like
device is inserted into a small hole in the soil
to give real-time, immediately accurate and
reliable information on pollution and the
all-round health of the soil. It will eliminate
the requirement of satellite soil mapping and
hence decreasing cost.
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Optical method of soil moisture sensing.

• Optical method relay on the changes in the
  characteristics of light due to soil
  characteristics. Method involve use of polarized
  light, fiber optic sensors, and near infrared
  sensors.
• Polarization method is based on the principle
  that presence of moisture at the surface of
  reflection tends to cause polarization in
  reflected beam.
• Fiber optic sensors are based on a section of
  unclad fiber embedded in the soil. Light
  attenuation in the fiber varies with the amount
  of soil water in contact with the fiber because
  of its effect on the critical angle of internal
  reflection.
• Near infrared methods depend on absorption at
  distinct wavelength by water in the surface
  layer.
• Measured parameter soil water content.
• Response time instantaneous.

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when energy hits the object (leaf) it can be
absorbed, transmitted and reflected. The fraction
of energy reflected at a particular wavelength
varies for different features. Additionally, the
reflectance of features varies at different
wavelengths. Thus, two features that are
indistinguishable in one spectral range may be
very different in another portion of the
spectrum. Therefore, this essential property of
matter allows different features to be identified
and separated by their spectral signatures.
Interaction between energy source, leaf
structure and spectral sensor.
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General plant reflectance.
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Spectral Characteristics of Vegetation
Partitioning of Vegetation Spectral Reflectance
in the VIS, NIR and MIR regions of the
electromagnetic spectrum.
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Photo-Chemistry

• Light may be absorbed and participate (drive) a
  chemical reaction. Example Photosynthesis in
  plants

• The frequency (wavelength) must be correct to be
  absorbed by some participant(s) in the reaction
• Some structure must be present to allow the
  reaction to occur
• Chlorophyll
• Plant physical and chemical structure

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Primary and secondary absorbers in plants

• Primary
• Chlorophyll-a
• Chlorophyll-b
• Secondary
• Carotenoids
• Phycobilins
• Anthocyanins

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Table . Absorption features related to common
quality components.
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Stressed vegetation and healthy vegetation have
different reflectance.
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Soil and crop reflectance
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NDVI Normalized Difference Vegetative Index

• Difference increases with greater red absorption.
• Increase or decrease in total irradiance does not
  effect NDVI
• Typically computed with irradiances, use of
  reflectance eliminates spectral shift sensitivity
• The spreading of the NDVI over a plant (or an
  entire plot) characterizes the state of the plant
  (age, leaf area index, health in some extend).

Above is a legend for leaf color and
corresponding NDVI reading.
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Smart Crop
An automated infrared sensor system tells farmers
when plants are thirsty or hotter than their
ideal growing temperature and need cooling off
with irrigation water.
Battery-operated infrared thermometers placed in
irrigated fields monitor leaf temperatures and
relay that information to a computerized base
station. A cell phone modem can be hooked up to
the base station to download data to a personal
computer. This modem can also send text messages
to a farmer's cell phone. An automated infrared
sensor system tells farmers when plants are
thirsty or hotter than their ideal growing
temperature and need cooling off with irrigation
water. Farmers can choose the time-temperature
threshold at which they would like to gain an
alert, and adjust it at any time.
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Optical Instrument for weed control.

• Commercially-available technologies
• Photonic Detection Systems Pty Ltd (formerly Weed
  Control Australia)
• Weedseeker , greenseeker and
• Rees Equipment.

• Photonic Detection Systems Pty Ltd
• A spot spraying system assess the spectral
  differences between weeds and the bare ground.
• The product discriminated different plant sizes
  and included a light source under a shade
  structure which improved accuracy.
• Modern version measures reflectance at three
  wavelengths using laser diodes and a line scan
  image sensor for intended use to discriminate
  vegetation species

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WeedSeeker
How a WeedSeeker sensor works
1.LEDs produce a combination of invisible
infrared and visible red light which is projected
onto the target approximately 600nm below the
sensor. 2.Light reflected from the target is
capture by a detector at the front of the
sensor. 3.Sophisticated electronic circuits
inside the sensor analyze the reflected light and
determine when it matches the light reflected by
green plants. 4. When green plants reflectance
is identified, the sensor waits until the plant
is under the spray nozzle and then triggers a
fast-fast solenoid valve which spray the plant.
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Greenseeker
Greenseeker optical sensor technology enables
one to measure, in real time, a crops nitrogen
levels, and variably apply the prescribed
nitrogen requirements.
1. Sensor scans the crop using LED lights. 2.
Optically senses crop's health using vegetative
index (NDVI). 3. Predicts yield potential. 4.
Prescribes optimum zone nitrogen rate. 5.
Delivers variable rate application. 6. Zone size
0.1ha to 0.2ha (dependent on speed and
controller). 7. Utilises existing controller and
plumbing. 8. Can apply liquid UAN, UREA and NH3.
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Continue
Working on same principle, GreenSeeker have some
advantages over WeedSeeker. Its not only a
sprayer but also senses plants different spectral
characteristics and gives its status. Advantages
Fast and precise optical sensing Reduce your
in-crop fertilizer costs Only apply nitrogen to
plants that need it Real time variable rate
fertilizer application Collect data during
existing farming operations Record NDVI
health/vigor data mapping throughout the season
Powerful remote sensing and agronomic research
tool Biomass and plant canopy measurement
Significantly reduce the impact to the
environment
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• Rees Equipment
• A active system that identify weeds based on
  colour and basic shape and size properties using
  video image analysis.
• The vegetation is identified as weed and sprayed
  if the detected colour and shape matched an
  operator-defined prescription.
• Image analysis Identification of weeds, crop or
  both.
• Species classification based on leaf shape
• images with distinct shapes representing
  individual leaves. (e.g grass and
• broad-leaf species)This occurs when the plants
  of interest are not touching
• due to their small size and dispersed spacing.
• Species classification based on spectral/colour
  differences
• may be used in situations where there are
  distinct colour differences
• between the species required for classification.
  
• Species classification based on texture
• homogeneity, structuredness and brightness

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Crop row geometry Crops are expected to occur
along the seed-row whereas weeds may occur both
along the seed-row and between crop rows. Any
vegetation (green pixels) that occur out of crop
rows is classified as weeds. The intensity of
the green reflectance determine the amount of
herbicide applied.
The weed-fighting system can distinguish between
intentionally cultivated crops, in green, and
weeds, in red.
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Indoor farming and Horticulture using artificial
light.
What if we could grow fruits and vegetables in
half the time with no pesticides or hormones and
use 90 percent less water to do it? What if we
could grow those fruits and vegetables anywhere
in the world, during any season?
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• Advantages of indoor farming
•  Less dependency on the environmental influences.
•  Less energy consumption
• Focus on lighting source which can affect the
  plant growth at a maximum.
• Makes the cultivation of the plant safely and
  securely
• Eliminate seasonal influence of the length of
  sunshine duration, climate and other
  environmental elements.
• Eliminate transportation of regional crops.

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Light Not All Light Is The Same. Just Ask A
Plant!
Plants convert light from the sun into energy
through the process of photosynthesis, but plants
only need some parts of the suns color spectrum.
Artificial light sources like LEDs can provide
just the light a plant needs, making the process
more efficient and growing a stronger, healthier
plant. Different plants need different wavelength
and intensity of light.
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Role of different light colours in plant growth
development
Blue Light The shorter wavelengths of blue light,
also known as cool light, trigger chlorophyll
production, ends plant dormancy and starts the
development process. Plants initially grown
under blue light will have compact growth with
thick leaves and strong stems. Red
Light Combining the longer wavelengths of the red
light spectrum with the shorter blue light
spectrum wavelengths will begin the next phase of
plant growth. This phase encompasses
germination Help in development of the plant's
underground network of roots, tubers or bulbs
Cause blooming and the development of
fruit. Cause photomorphogenesis. Green and
Yellow Light these two wavelengths have little
effect on plant growth.
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LED lightings were set for the purpose to
research the effects on the strawberries. Red,
blue, white and the case of no lighting
supplement, were set up individually in 4
different sections.
Red section Leaf stems grew longest and each
leaves were shaped most richly, comparing with
the ones in other sections. Blue section The
growth of leaf stems was shorter but thicker,
comparing it in Red section. The length of leaves
was longest. White section Leaf stems grew
slightly better than the ones in no lighting
supplement section. Highest sugar content rate
was recorded in this section.
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In indoor farming large focusing mirrors are used
in order to give natural light to plants.
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Refractometer

• Measure the nutritional content of fruits and
  vegetables to check the ripening stage of fruit
  and the sugar content of fruits and grapes,.
• It works on the principle of light bending when
  it passes from air into solution.
• The amount light bends is measured in degrees
  "Brix".
• There are values of degrees Brix for each fruit
  and vegetable ranging from poor to excellent.
• The excellent level generally gives the plant
  immunity to disease and insects, and creates
  health in animals and people.
• These plants also have increased frost
  resistance, and improved storability because they
  will dehydrate rather than rot.

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Continue..

• refractometers are used by farmers to check the
  ripening stage of fruit and the sugar content of
  fruits and grapes,
• its readings can be correlated to insect and
  disease infestations, mineral content, shelf
  life, crop vigor, palatability, and chemical
  contamination.
• It is also used to check soil nutrition content.
• Refractometers are also used to measure salinity
  and specific gravity of water.
• Doctors use it to measure total plasma protein in
  blood.

When a refractometer is used, the Brix value can
be obtained Bx (((((11758.74nD
-88885.21)nD 270177.93)nD - 413145.80)nD
318417.95)nD -99127.4536) where nD is the
refractive index, measured at the wavelength of
the sodium D line (589.3 nm) at 20 C.
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Measuring the Quality of Fruits and Vegetables
with the Refractometer( Sucrose or Degrees Brix)
 FRUITS POOR AVERAGE GOOD EXCELLENT
Apples 6 10 14 18
Avocados 4 6 8 10
Bananas 8 10 12 14
Cantaloupe 8 12 14 16
Casaba 8 10 12 14
Cherries 6 8 14 16
Coconut 8 10 12 14
Grapes 8 12 16 20
Grapefruit 6 10 14 18
Honeydew 8 10 12 14
Kumquat 4 6 8 10
Lemons 4 6 8 12
Limes 4 6 10 12
Mangos 4 6 10 14
Oranges 6 10 16 20
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Continue..
VEGETABLES POOR AVERAGE GOOD EXCELLENT
Asparagus 2 4 6 8
Beets 6 8 10 12
Bell Peppers 4 6 8 12
Broccoli 6 8 10 12
Cabbage 6 8 10 12
Carrotsa 4 6 12 18
Cauliflower 4 6 8 10
Celery 4 6 10 12
Corn Stalks 4 8 14 20
Corn (Young) 6 10 18 24
Cow Peas 4 6 10 12
Endive 4 6 8 10
English Peas 8 10 12 14
Escarole 4 6 8 10
Field Peas 4 6 10 12
Green Beans 4 6 8 10
Hot Peppers 4 6 8 10
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Thank you . . .
ISP,CUSAT