Fluorescence imaging - a new tool for weed sensing?

ARI Agricultural Research Institute Kromeriz Ltd.

Fluorescence imaging - a new tool for weed sensing?

Karel KLEM, Ladislav NEDBAL


Bottlenecks of implementing site specific weed management

• Weed detection– labour intensive visual assessment– automatic weed detection (on-line or off-line)

• Decision support systems – economic thresholds (short term) or economic

optimum thresholds (long term) – adjusting of herbicide dose or long term

rationalisation of herbicide use


Present state of automatic weed detection

• several methods are available1. reflectance masurements in NIR spectrum

• not species specific

• in narrow row crops difficult to distinguish between crop and weed

2. image analysis systems• the shapes of different plants overlap and vary

greatly because of different viewing angles in field conditions


There is a possibility of improving weed detection using a new approach based on unique method of chlorophyll fluorescence imaging (PSI Brno, Czech Republic). Fluorescence kinetics is measured with this instrumentation for every pixel of the image.

Chlorophyll fluorescence imaging


QA- QA

- QA- QA

- QA- QA

-

fluorescence

In fluorescence, the actinic light elicits in plants the Kautsky effect of

fluorescence induction.

from F0 with open PSII RC’s

to FPEAK with mostly closed PSII RC’s


• 2 dimensional map of weed and crop plants distribution

• very strong discrimination between plants and background

• kinetics of fluorescence signal for each selected object

•species specific differencies in fluorescence kinetics (crop/ weed and weed/weed)

Results of fluorescence imaging


• possibility to use different measurement protocols (wizard or own protocol)


The objects for analysis can be selected manually.

Objects identification that will be analyzed as distinct entities with a characteristic fluorescence

emission

Alternatively the analysis can be done semi-automatically using either directly the fluorescence signal or its gradient.

Alternatively the analysis can be done semi-automatically using either directly the fluorescence signal or its gradient.

For a semi-automatic selection, the Low and High limits of the signal are defined and the areas conforming to these limits are colored in red.


sergj


Average fluorescence kinetics for winter wheat and selected weed species

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APESV TRIAE MATIN SINAL


Measurement of fast chlorophyll fluorescence iduction with portable PEA (Hansatech) instrument

• 2 s experiment• light adapted samples• computer based data

processing (software BIOLYZER)

• Output: fluorescence kinetics and photosynthetic parameters


Variation in fluorescence kinetics (kautsky eff.) between 11 winter wheat varieties

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Fluorescence kinetics by 11 winter wheat varieties

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alana01.alana02.alana03.

alana04.alana05.alana06.alana07.alana08.

alana09.apache01apache02apache03apache04apache05apache06apache07apache08

apache09apache10brea01.dbrea02.dbrea03.dbrea04.dbrea05.dbrea06.dbrea08.d

brea09.d

brea10.debi01.daebi02.daebi03.daebi04.daebi05.daebi06.daebi07.daebi08.daebi09.daestica01estica02estica03estica04estica05estica06estica07estica08estica09estica10

hana01.dhana02.dhana03.dhana04.dhana05.dhana06.dhana07.dhana08.dhana09.dhana10.d

nela01.dnela02.dnela04.d

nela05.d

nela06.dnela07.dnela08.dnela09.d

nela10.d

niagar01niagar02niagar03niagar04niagar05niagar06niagar07niagar08niagar09niagar10

record01record02

record03

record04record05record06record07record08record09record10

saskia01saskia02

saskia03saskia04saskia05saskia06saskia07saskia08saskia09saskia10

versai01versai02versai03versai04versai05versai06versai07versai08versai09versai10


Differences in fluorescence kinetics of Apera spica-venti in three different growth stages

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Differences in fluorescence kinetics of Apera spica-venti by different growth stages

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ape204.dape205.dape206.dape207.dape208.dape209.dape210.d

AVG3ape301.d

ape302.d

ape303.dape304.d

ape305.d

ape306.dape307.dape308.dape309.dape310.dAVG4ape3a71.

ape3a72.ape3a73.

ape3a74.

ape3a75.

ape3a76.

ape3a77.ape3a78.

ape3a79.

ape3a80.


Variation in fluorescence kinetics measured in two different growth stages of Sinapis alba

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Variation in fluorescence kinetics of Sinapis alba in cotyledons stage

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sin301.dsin302.d

sin303.dsin304.d

sin305.d

sin306.d

sin307.dsin308.d

sin309.d

sin310.d

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Variation in fluorescence kinetics of Sinapis alba in first pair of true leaves stage

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sinb01.d

sinb02.dsinb03.dsinb04.dsinb06.dsinb07.dsinb08.dsinb09.d

sinb10.d


Differences in fluorescence kinetics between winter wheat and Apera spica-venti plants (2 leaves)

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Differences in fluorescence kinetics between winter wheat and Apera spica-venti (2 leaves and more)

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apache01apache02apache03apache04apache05apache06apache07apache08

apache09apache10

ape301.d

ape302.d

ape303.dape304.d

ape305.d

ape306.dape307.dape308.dape309.dape310.d


Differences in fluorescence kinetics between winter wheat and Matricaria perforata in two growth

stages

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Differences in fluorescence kinetics between winter wheat and Matricaria perforata (cotyledons)

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apache09apache10

mat201.dmat202.d

mat203.dmat204.d

mat205.d

mat206.d

mat207.dmat208.d

mat209.d

mat210.d

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Differences in fluorescence kinetics between winter wheat and Matricaria perforata (true leaves)

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apache09apache10

mat371.dmat372.d

mat373.d

mat374.dmat375.dmat376.dmat377.d

mat378.d

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Amaranthus retroflexus

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ama110.dama111.dama112.dama113.dama114.dama115.dama116.dama117.dama118.dama119.dama120.dama121.dama122.dama123.dama124.dama125.dama126.dama127.dama128.dama129.dama130.d


apache09apache10

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Chenopodium album

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chen851.chen852.chen853.chen854.chen855.chen856.chen857.chen858.chen859.chen860.chen861.chen862.chen863.chen864.chen865.chen866.chen867.chen868.chen869.chen870.chen871.chen872.

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Sinapis alba

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apache09apache10sinc42.dsinc43.dsinc44.dsinc45.d

sinc46.d

sinc47.dsinc48.d

sinc49.d

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Galium aparine

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clog101.clog102.clog103.clog104.clog105.clog106.

clog107.clog108.clog201.

clog202.clog203.clog204.clog205.

clog206.clog207.clog208.clog301.clog302.clog303.clog304.clog307.


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Species-specific differences in photosynthetic parameters


Pattern recognition

Neural network - most popular automatic discriminant method used in pattern recognition

fluorescence, photosynthetic or shape parameters

APESV TRIAE

X1 X2 X3 X4


Decision support systems

• Economic thresholds or adjusting of herbicide dose

• Need long-term evaluation of influence on:– weed population dynamics– economic output– total ammount of herbicide input into

environment


Population dynamics of Galium aparine as influenced by decision system

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Starane 250 EC dose and efficacy0 1 2 3 4 5 60 l 0,4 l 0,4 l 0,4 l 0,4 l 0,4 l 0 lA - Economic threshold0% 100% 100% 100% 100% 100% 0%0 l 0,1 l 0,15 l 0,15 l 0,15 l 0,15 l 0,15 lB - Adjusting of herbicide

dose 0% 92% 98% 98% 98% 98% 98%


Conclusion• Fluorescence imaging has a considerable

potential for improoving of automatic weed detection– species specific– undependent on viewing angle and leaf

overlappings

• This approach need extensive technical and experimental improovement and connection to decision support systém

Fluorescence imaging - a new tool for weed sensing?

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