=Paper= {{Paper |id=Vol-3126/paper50 |storemode=property |title=Validation of data obtained after field sensing using UAV for management of future crops |pdfUrl=https://ceur-ws.org/Vol-3126/paper50.pdf |volume=Vol-3126 |authors=Natalia Pasichnyk,Dmytro Komarchuk,Oleksiy Opryshko,Yurii Gunchenko,Sergey Shvorov,Oksana Zui }} ==Validation of data obtained after field sensing using UAV for management of future crops== https://ceur-ws.org/Vol-3126/paper50.pdf
Validation of Data Obtained After Field Sensing Using UAV for
Management of Future Crops
Natalia Pasichnyk1, Dmytro Komarchuk2, Oleksiy Opryshko3, Yurii Gunchenko4, Sergey
Shvorov5, Oksana Zui6
1,2,3,5
      National University of Life and Environmental Sciences of Ukraine, Heroyiv Oborony st., 15, Kyiv, 03041,
Ukraine
4,6
    Odessa I.I.Mechnikov National University, Dvoryanskaya str., 2, Odessa, 65082, Ukraine

                  Abstract
                  UAVs are innovative equipment for monitoring fields that are free from a lot of the
                  disadvantages of satellites such as availability, low cost, and high image resolution. However,
                  the issues of quality, reproducibility, and suitability for crop management processes remain
                  relevant. Now, the issue of assessing the suitability of the results of spectral monitoring of
                  plantations in relation to the condition of plants has not been resolved. Since spectral monitoring
                  is a necessary component in the concept of crop management, the development of a
                  methodology for assessing the suitability of remote monitoring spectral data for the calculation
                  of agrochemical practices was the purpose of the work. According to the publications, the
                  dependence of the number of pixels on the values of the intensity of color components for plants
                  and soil is described by the Gaussian distribution. Deviation from such distribution is caused
                  by the imposing of distributions from various objects fixed on a photo. The experimental test
                  was carried out on the basis of wheat, using the results obtained during 2017-2020 when
                  considering the stresses of nutrient deficiency and technological nature. The investigation found
                  experimental evidence that the pixel distribution of plantations on the example of the wheat
                  crop is described by the Gaussian distribution. It was found that the analysis of the
                  correspondence of the nature of the distribution on the spectral channels, namely the presence
                  of several max peaks that affects the value of the distribution maximum may indicate the
                  presence of foreign inclusions or a transitional stage of vegetation. The suitability of the data
                  can be assessed on the basis of the reference values of the width of the distribution on the
                  spectral channels. Vegetation indices GNDVI and RNDVI were unsuitable for assessing the
                  suitability of the data based on the parameters of the pixel distribution of the image in the
                  experimental plots. This determines the feasibility of introducing in the sets of regular
                  vegetation indices of geographic information systems additional packages that reflect the
                  spectral channels.

                  Keywords 1
                  UAV, spectral monitoring, crop management, data validation


1. Introduction                                                                               of fundamental shortcomings of satellites in terms
                                                                                              of availability, cost, image resolution. However,
                                                                                              the issues of quality, reproducibility, and
  UAVs are innovative equipment for
                                                                                              suitability for crop management processes remain
monitoring fields, which are deprived of a number

ISIT 2021: II International Scientific and Practical Conference
«Intellectual Systems and Information Technologies», September
13–19, 2021, Odesa, Ukraine
EMAIL:           N.Pasichnyk@nubip.edu.ua          (A.       1);
dmitruyk@gmail.com (A. 2); sosdok@nubip.edu.ua (A. 3);
gunchenko@onu.edu.ua (A. 4); ozon.kiev@nubip.edu.ua (A. 5);
oks.zuj@gmail.com(A. 6)
ORCID: 0000-0002-2120-1552 (A. 1); 0000-0003-3811-6183 (A.
2); 0000-0003-3358-1297 (A. 3); 0000-0003-4423-8267 (A. 4);
0000-0001-6433-3566 (A. 5); 0000-0001-9520-4441 (A. 6)
              ©️ 2021 Copyright for this paper by its authors. Use permitted under Creative
              Commons License Attribution 4.0 International (CC BY 4.0).
              CEUR Workshop Proceedings (CEUR-WS.org)
relevant. More often, designers focus on the           others (2021) in [2]. Information on plant
improvement of spectral equipment, but there are       dimensions is useful for determining stress
also methodological problems in the perception         conditions, but in the early stages of the growing
and interpretation of information from devices of      season, accurate image resolution is required for
technical vision. Thus, most of the vegetation         accurate identification, which can only be
indices currently used to interpret UAV data, such     obtained from low altitudes, which will not
as NDVI, were developed for satellite platforms        contribute to the scalability of technology on an
with their inherent low image resolution when          industrial scale. An alternative technical means
each pixel had a group of plants. The indices          for estimating plant dimensions are LiDARs
developed on the basis of the soil line concept        described in the review article by Yue Pan and
were primarily intended to assess the availability     others (2019) in [3]. However, such innovative
of biomass, and crop management issues require         equipment for small plants, with a leaf width of
other methodological approaches to crop                several millimeters, according to Tai Guoa and
monitoring. It should be borne in mind that the        others (2019) in [4].
implementation of agrochemical measures, in                Another approach is based on the use of
particular fertilization should be carried out only    reference values of plant spectral indicators to
at certain stages of the growing season. However,      identify the spread of forest pests described in Per-
the state of plant development is determined by        Ola Olsson and others (2016) in [5]. The estimate
many factors, including the state of mineral           is based on recording the deviation from the
nutrition, water supply, etc., so within one field     seasonal changes of the NDVI index is designed
there may be a situation when the plants are at        for different stages of the growing season because
different stages of the growing season.                satellite imagery is carried out at high intervals
Accordingly, in such situations, the calculation of    and you can select data for uniquely the same
the mean value over the site, which is inherent in     stage of the growing season. A similar approach
satellite solutions, is erroneous. At present, the     to the selection of spectral data from an existing
issue of assessing the suitability of the results of   array of rapidly changing data is shown in the
spectral monitoring of plantations in relation to      work of Ameer Shakayb Arsalaan and others
the condition of plants has not been resolved.         (2016) in [6] on the example of forest fires.
Since spectral monitoring is a necessary               However, under normal conditions, farms in crop
component in the concept of crop management,           management should be able to decide on the basis
the development of a methodology for assessing         of a single departure on the need for additional
the suitability of remote monitoring spectral data     flights that require free equipment.
for the calculation of agrochemical practices was          An original approach to the identification of
the purpose of our work.                               plants in terms of changes in their dimensions on
                                                       the example of sugar beet is shown in the work of
2. The state of the issue                              Yang Cao Liu and others (2020) in [7].
                                                       Researchers have proposed a new wide-dynamic-
                                                       range vegetation index (WDRVI) where an
   The spectral performance of objects critically      additional coefficient is introduced for the
depends on the state of illumination, and the          infrared channel. However, in production, the
reproducibility of data is tried to ensure by a        achieved accuracy increase of up to 5% should
combination of technical and organizational            still recoup the cost of determining the
measures. The work of Helge Aasen and others           dynamically changing coefficients for the infrared
(2015) in [1] considered the construction of 3D        channel. That is, the most promising approach is
models of plants, where to ensure accuracy, they       based on the comparison of spectral indices with
proposed a method of combining data from               certain reference samples.
several flights. Despite the interesting and               Spectral indicators of plants, even those that
encouraging results, such a technique will require     are in the same stage of the growing season have
several flights in a row from different directions,    some differences. To obtain the average value for
which is unsuitable for industrial-scale in            plants when fixing the soil in a photograph,
conditions of time shortages. An approach to           Yaokai Liu et al. (2012) in [8] proposed the use of
determine the features of the dome of plants in the    Gaussian distribution combinations where the
mass phenotyping of plants using UAVs based on         ranges belonging separately to plants and soil
a comparison of the obtained portraits with            were recorded. Positive results were obtained, but
reference templates is shown in Fusang Liu and
                                                       the resolution of images from a height of 3 m was
very high, which is difficult to implement on an      the color components for plants and soil is
industrial scale. According to the data presented     described by the Gaussian distribution. Deviation
in the work of Guangjian Yan and others (2019)        from such distribution is caused by the imposing
in [9], when the resolution of the images is          of distributions from various objects fixed on a
reduced, the ability to select individual ranges      photo. However, experiments were performed in
corresponding to the soil and plants is lost.         hospitals where the plants were in one phase of the
Improving identification by estimating the            growing season in the air-dry state of the soil,
intensity distribution of color components is         respectively, it is advisable to check the suitability
shown in André Coy et al. (2016) in [10] where        of the method and in moist soil.
the CIE L * a * b * space model was used instead
of the RGB color model. The authors have              3. Materials and research software
proposed threshold values to determine the area of
the dome, but this approach will be effective only       and hardware
in the initial stages of the growing season when in
particular the shade on the lower tiers of plant          The research was carried out on the basis of
leaves can be neglected. The method was               wheat, using the results obtained during 2017-
improved in the work of Linyuan Li et al. (2018)      2020. Stresses due to lack of nutrients were
in [11], when the identification of soil and plants   studied in the fields of the long-term stationary
was attempted on the basis of the Gaussian half-      experiment of the Department of Agrochemistry
distribution. This approach allows you to identify    and Plant Quality of NULES of Ukraine, where
2 components, but in the case of 3 components, its    fertilizer application systems are studied.
efficiency is questionable.                           Technological stresses were studied on and in the
    Thus, based on the analysis of the literature,    production fields of farms in the Kyiv region. In
we can conclude that the dependence of the            fig. Green Chlorophyll index distribution maps
number of pixels on the values of the intensity of    are presented (Fig. 1).




Figure 1: Green Chlorophyll index distribution maps on the research hospital on the left and
production fields (on the right) are created by Slantrange software. Blue intersections highlight
checkpoints for accurate positioning of pixels of different spectral channels and index distribution
maps

   The experiments were performed in the optical      Dolia and others (2019) in [13] (2019).
range using a standard UAV camera DJI Phantom         Multispectral studies using the infrared range
3+. A description of the methodology of               were performed using the Slantrange 3p system
experimental research was covered in the work of      and Slantview software (version 2.13.1.2304)
V. Lysenko and others (2017) in [12] and M.           designed specifically for this sensor equipment. A
feature of Slantview software is the ability to
quickly and autonomously create vegetation                                                        As can be seen from the above data when using
distribution maps directly in the field. Slantview                                            the proposed method, it was found that the value
software compiles a general orthophoto from                                                   of the maximum distribution shifted by 2 units,
images, corrects for lighting, and provides the                                               while reducing the width w by 3 units. The
user with ready-made maps of the distribution of                                              presence of the Max2 distribution can be
vegetation indices such as various NDVI variants.                                             explained both by the presence of shadow on the
Slantview software can export data to geotiff                                                 lower and upper leaves and by the fixation of the
format. Areas of rapeseed with and without signs                                              soil.
of technological stress were considered for                                                       The proposed approach to the processing of
research. Data on individual spectral channels and                                            experimental results will be effective if the
vegetation indices calculated by the Slantview                                                condition Max1≫ Max2 is satisfied. In practice, a
program were considered. The research                                                         situation is possible when plants of the same crop
methodology is described in the work of S.                                                    are in the field at the same time, but at different
Shvorov and others (2020) in [14]. Maximum                                                    stages of the growing season or in a fundamentally
detail (GSD 0.04 m / pixel) was obtained from the                                             different physiological state, such as the
Slantview software image window (available                                                    appearance of a flag leaf, which was recorded on
NDVI index variants - Green, Red, and RedEdge).                                               06.08.2018. According to the presented in fig. 3
Monochrome images were used to study the                                                      data Max1≅Max2, so the approach was used
results on separate spectral channels (image                                                  when at the first stage separately determined
window), which were stored in BMP format to                                                   separately 2 Gaussian distributions, after which
ensure the completeness of the information. To do                                             the calculations were carried out according to the
this, a copy of the screen was saved in Paint                                                 method proposed in section 3.
(Microsoft Windows 7.0 Sp.1).

                                                                                                                  600
4. The results and discussions were                                                                                               Wheat
                                                                                                                                  All xc=170, w=28;
   obtained                                                                                                       500
                                                                                                                                  Max1 xc=156, w=16;
                                                                                                                                  Max2 xc=193, w=12;
                                                                                               Number of points




                                                                                                                  400             Max3 xc=118, w=17;
   In fig. 2 shows the results of calculations for                                                                                Max1+Max2+Max3
the red component for experimental data obtained
                                                                                                                  300
on 2017.05.05 in studies of the impact on the
spectral indicators of the state of mineral nutrition
                                                                                                                  200
using a universal camera FC200 (a standard tool
for UAV DJI Phantom 3).                                                                                           100


                                                                                                                   0
                   1000                                                                                                 20   40   60   80   100 120 140 160 180 200 220 240 260
                                   Wheat
                                   All xc=116, w=25;                                                                                          Red color intensity
                                   Max1 xc=118, w=22;
                   800
                                   Max2 xc=64, w=23.
                                                                                              Figure 3: The results of approximation of the
                                                                                              dependence of the number of pixels on the
Number of points




                   600                                                                        intensity of the red component of the color for
                                                                                              winter wheat (2018.06.08 - there is a flag sheet)
                   400
                                                                                                 Detection of the presence of several individual
                   200                                                                        maxima can be done based on the magnitude of
                                                                                              the distribution when using to approximate the
                     0
                                                                                              experimental data. For the presented data, the
                          0   20      40   60     80    100   120     140   160   180   200   value was 28 while in the remaining sections was
                                                Red color intensity                           18… 23.
Figure 2: The results of the approximation of the                                                Based on the obtained results, the results
dependence of the number of pixels on the                                                     obtained by approximating all the data by a single
intensity of the red component of color                                                       Gaussian dependence (All) are incorrect because
(05.05.2017)                                                                                  they do not correspond to any of the distribution
                                                                                              maxima. That is, monitoring was performed when
the plants were in a transitional state and                                      carried out in production fields near the village of
monitoring should be repeated after a few days                                   Gvardiyske with the coordinates of lat. 50,0347
when the vast majority of plants in the field are in                             long. 30,0286 is presented in fig. 5.
a single stage of vegetation. For automatic                                          According to the results obtained under stress
processing of monitoring results, reference values                               conditions, the width of distribution on both the
for distribution parameters can be obtained in                                   green and red channels is 1.5≤ times greater than
stationary experiments, etc.                                                     in healthy plants. On the red channel, regardless
    For universal digital cameras in the optical                                 of the presence of technological stresses, 2
range, such as FC200, strict compliance with the                                 pronounced maxima of distribution were not
selectivity of light filters is not required, so to                              observed, in contrast to the results in Figs. 4,
verify the results, a study was conducted using a                                regardless of the channel, the coefficient of
specialized spectral complex Slantrange 3. The                                   determination is 0.98≤R2. According to the
results of mineral nutrition studies are presented                               authors, the difference in plant development is
in Fig. 4.                                                                       explained by the difference in climatic factors due
                                                                                 to the location of the plots, so the production field
                                                                                 is protected by dense forest strips in contrast to the
                                                                2
                   3000                G Fertilizers MIN w=7.1, R =0,98;         used area of the experimental hospital.
                                                                   2
                                       G Fertilizers MAX w=3.6, R =1;
                                                                 2
                                       R Fertilizers MIN w=18, R =0.84;
                   2500                                            2
                                       R Fertilizers MAX w=9.8, R =0.98;
                                                                                                        260
Number of pixels




                   2000                                                                                       G Teh.str. +, w=8.4;
                                                                                                        240
                                                                                                              G w=5.5;
                                                                                                        220   R Teh.str. +, w=9;
                   1500
                                                                                                        200   R w=5,6.

                                                                                                        180
                   1000
                                                                                     Number of pixels




                                                                                                        160
                                                                                                        140
                   500
                                                                                                        120
                                                                                                        100
                     0
                          20   40          60              80              100                          80

                                    Spectral channel                                                    60

Figure 4: Dependence of the number of pixels on                                                         40
                                                                                                        20
the value of the intensity of the green (G) and red
                                                                                                         0
(R) components of the color and the wall of                                                                                 50                             100
mineral nutrition at a dose of mineral fertilizers                                                                               Spectral channel
(Fertilizers MAX) and without fertilizers                                        Figure 5: Dependence of the number of pixels on
(Fertilizers MAX). Date of research 2020.04.27                                   the intensity of the green (G) and red (R)
                                                                                 components of color and the presence of
    When approximating the experimental data by                                  technological stresses (The.str). Date of research
the GaussAmp dependence, the distribution width
                                                                                 2020.04.27
for the green channel was 7.1 for plants under
stress and 3.6 for healthy plants, respectively, at
0,98≤R2. For the red component, regardless of the                                5. Wheat (distribution                                             maps     of
state of mineral nutrition, the imposition of 2                                     vegetation indices)
maxima will be recorded, which were more
pronounced in the absence of nutrients. Similarly                                    Since the experimental plots with different
to the green channel, the calculated distribution                                fertilizer contents of the stationary experiment
width in healthy plants was approximately twice                                  have a relatively small width of 5 meters for
less than in stress plants 9, 8 and 18, respectively.                            remote sensing using a UAV, the results obtained
The coefficient of determination at 1.5 doses of                                 from the Slantview software map window were
mineral fertilizers was 0.98 and for affected plants                             used for the research. The obtained results are
0.84.                                                                            shown in Fig. 6 for stresses caused by the state of
    The results of research on the technological                                 mineral nutrition and technological stresses,
stress caused by the action and aftereffect of                                   respectively.
herbicides from the predecessor culture were
    Based on the data obtained for the distribution                                                                   Data suitability can be assessed on the basis of
of the NDVI index, there is a difference in the                                                                   spectral channel width reference values.
distribution of spectral channels. Thus, the width                                                                    Vegetation indices GNDVI and RNDVI were
of the distribution regardless of the nature of stress                                                            unsuitable for assessing the suitability of data
in stress plants was similar or even smaller than in                                                              based on the parameters of the pixel distribution
healthy plants. The coefficient of determination                                                                  of the image in the experimental plots. This
was 0.85-0.95, it was much lower than in the                                                                      determines the feasibility of introducing in the
green and red spectral channels.                                                                                  sets of regular vegetation indices of geographic
                                                                                                                  information systems additional packages that
                                                                                                                  reflect the spectral channels.
                          800
                                                            GNDVI Fertilizers MIN, w=0,005;
                                                            GNDVI Fertilizers MAX, w=0,010;
                          700
                                                            RNDVI Fertilizers MIN, w=0,01;                        7. References
                          600                               RNDVI Fertilizers MAX, w=0,01.
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