scholarly journals Combining Color Indices and Textures of UAV-Based Digital Imagery for Rice LAI Estimation

2019 ◽  
Vol 11 (15) ◽  
pp. 1763 ◽  
Author(s):  
Songyang Li ◽  
Fei Yuan ◽  
Syed Tahir Ata-UI-Karim ◽  
Hengbiao Zheng ◽  
Tao Cheng ◽  
...  
Keyword(s):  
Digital Images ◽  
Oryza Sativa L ◽  
Accuracy Assessment ◽  
Stem Elongation ◽  
Growth Stages ◽  
Digital Imagery ◽  
Area Index ◽  
Practical Applications ◽  
Color Indices ◽  
Promising Solution

Leaf area index (LAI) is a fundamental indicator of plant growth status in agronomic and environmental studies. Due to rapid advances in unmanned aerial vehicle (UAV) and sensor technologies, UAV-based remote sensing is emerging as a promising solution for monitoring crop LAI with great flexibility and applicability. This study aimed to determine the feasibility of combining color and texture information derived from UAV-based digital images for estimating LAI of rice (Oryza sativa L.). Rice field trials were conducted at two sites using different nitrogen application rates, varieties, and transplanting methods during 2016 to 2017. Digital images were collected using a consumer-grade UAV after sampling at key growth stages of tillering, stem elongation, panicle initiation and booting. Vegetation color indices (CIs) and grey level co-occurrence matrix-based textures were extracted from mosaicked UAV ortho-images for each plot. As a solution of using indices composed by two different textures, normalized difference texture indices (NDTIs) were calculated by two randomly selected textures. The relationships between rice LAIs and each calculated index were then compared using simple linear regression. Multivariate regression models with different input sets were further used to test the potential of combining CIs with various textures for rice LAI estimation. The results revealed that the visible atmospherically resistant index (VARI) based on three visible bands and the NDTI based on the mean textures derived from the red and green bands were the best for LAI retrieval in the CI and NDTI groups, respectively. Independent accuracy assessment showed that random forest (RF) exhibited the best predictive performance when combining CI and texture inputs (R2 = 0.84, RMSE = 0.87, MAE = 0.69). This study introduces a promising solution of combining color indices and textures from UAV-based digital imagery for rice LAI estimation. Future studies are needed on finding the best operation mode, suitable ground resolution, and optimal predictive methods for practical applications.

scholarly journals Effect of row width on splash erosion and throughfall in silage maize crops

2017 ◽  
Vol 12 (No. 1) ◽  
pp. 39-50 ◽  
Author(s):  
V. Brant ◽  
P. Zábranský ◽  
M. Škeříková ◽  
J. Pivec ◽  
M. Kroulík ◽  
...  
Keyword(s):  
Stem Elongation ◽  
Field Measurements ◽  
Positive Influence ◽  
Row Spacing ◽  
Growth Stages ◽  
Area Index ◽  
Factors Affecting ◽  
Splash Erosion ◽  
Silage Maize ◽  
Plant Length

Line width is one of the major factors affecting arable soil erosion. The aim of the study was to assess the effects of different row spacing on splash erosion and throughfall in maize crops. Field measurements of the throughfall (P<sub>th</sub>, mm) and splash erosion (MSR, g/m<sup>2</sup>) were carried out in silage maize crops (row spacing 0.45 and 0.75 m) in 2012–2014. The BBCH growth stages for the crops, plant length (L, m), and leaf area index (LAI) were evaluated. Positive correlation was observed between the aerial precipitation (P, mm) and the P<sub>th</sub> values. With increasing P-values, higher levels of P<sub>th</sub> were identified in the 0.75 m compared to the 0.45 m row spacing. The value of this proportion was decreasing from the centre of the inter-row (0.75 m) to the row of the plants direction. Statistically significant lower values of splash erosion were observed in the 0.45 m compared with the 0.75 m wide rows, especially within the years 2012 and 2014. The experiments proved the positive influence of the length of plants and LAI on P/P<sub>th </sub>values. A decrease of P<sub>th </sub> in relation to precipitation values with height of plants and LAI values was observed. This dependency was then confirmed from the beginning of the stem elongation (BBCH 30) to the end of flowering (BBCH 70). Tighter dependency between the plant length (L) and the values of P/P<sub>th</sub> ratio in the 0.75 m wide crop rows was determined. Conversely, a more important influence of LAI on the values of P/P<sub>th</sub> ratio was estimated in the 0.45 m wide crop rows. The experiments proved the positive influence of the 0.45 m wide rows on the decrease of splash erosion as well as throughfall compared with the 0.75 m row spacing.  

scholarly journals Morphological and physiological performance of PSB Rc18 lowland rice (Oryza sativa L.) grown at different water, spacing and nutrient management

2019 ◽  
pp. 76-99
Author(s):  
Ruth Escasinas ◽  
Oscar Zamora
Keyword(s):  
Nutrient Management ◽  
Oryza Sativa L ◽  
Crop Productivity ◽  
Cell Number ◽  
Lowland Rice ◽  
Growth Stages ◽  
Area Index ◽  
Physiological Performance ◽  
Rice Plants ◽  
Continuous Flooding

Rice yield fluctuates because of environmental influences on morphological and physiological processes, as well as inadequate human intervention, to stabilize crop productivity. A field experiment was conducted in two cropping seasons at the experimental area of the Department of Agronomy, Visayas State University, Baybay, Leyte to evaluate the morphological and physiological performance of lowland rice grown at different water, spacing and nutrient management. Different sources of fertilizers were designated as the mainplot and plant spacing as the subplot nested within two water regimes, ie, continuous flooding and no flooding. Lowland rice s under no flooding were shorter than those under plant continuous flooding. No flooding gave higher root pulling resistance, crop growth rate, net assimilation rate, leaf area index and harvest index and consequently produced higher grain yield of PSB Rc18. No flooding and continuous flooding water management resulted in the formation of aerenchyma cells in roots of rice plants which had statistically similar cell number and measurement. Wider spacing of 40cmx40cm gave the highest RPR. Water, spacing and nutrient management did not influence the phyllochron and total number of leaves on the main culm of PSB Rc18. However, PSB Rc18 at early growth stages tended to have longer phyllochron because of transplanting shock. No flooding, application of composted goat manure and closer spacing of 20cmx20cm is the best treatment combination that g ve similar yield to rice plants a applied with inorganic fertilizer at the rate of 90-30-30kg ha-1 N, P2O5, K2O.

scholarly journals Morphological and physiological performance of PSB Rc18 lowland rice (Oryza sativa L.) grown at different water, spacing and nutrient management

2019 ◽  
pp. 76-99
Author(s):  
Ruth Escasinas ◽  
Oscar Zamora
Keyword(s):  
Nutrient Management ◽  
Oryza Sativa L ◽  
Crop Productivity ◽  
Cell Number ◽  
Lowland Rice ◽  
Growth Stages ◽  
Area Index ◽  
Physiological Performance ◽  
Rice Plants ◽  
Continuous Flooding

Rice yield fluctuates because of environmental influences on morphological and physiological processes, as well as inadequate human intervention, to stabilize crop productivity. A field experiment was conducted in two cropping seasons at the experimental area of the Department of Agronomy, Visayas State University, Baybay, Leyte to evaluate the morphological and physiological performance of lowland rice grown at different water, spacing and nutrient management. Different sources of fertilizers were designated as the mainplot and plant spacing as the subplot nested within two water regimes, ie, continuous flooding and no flooding. Lowland rice s under no flooding were shorter than those under plant continuous flooding. No flooding gave higher root pulling resistance, crop growth rate, net assimilation rate, leaf area index and harvest index and consequently produced higher grain yield of PSB Rc18. No flooding and continuous flooding water management resulted in the formation of aerenchyma cells in roots of rice plants which had statistically similar cell number and measurement. Wider spacing of 40cmx40cm gave the highest RPR. Water, spacing and nutrient management did not influence the phyllochron and total number of leaves on the main culm of PSB Rc18. However, PSB Rc18 at early growth stages tended to have longer phyllochron because of transplanting shock. No flooding, application of composted goat manure and closer spacing of 20cmx20cm is the best treatment combination that g ve similar yield to rice plants a applied with inorganic fertilizer at the rate of 90-30-30kg ha-1 N, P2O5, K2O.

scholarly journals Growth and yield of boro rice (Oryza sativa L.) in response to crop establishment methods and varieties

2020 ◽  
Vol 5 (2) ◽  
pp. 137-143
Author(s):  
Afrina Rahman ◽  
Md. Abdus Salam ◽  
Md. Abdul Kader ◽  
Md. Shafiqul Islam ◽  
Suriaya Perveen
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Oryza Sativa L ◽  
Direct Seeding ◽  
Growth And Yield ◽  
Growth Stages ◽  
Rice Cultivars ◽  
Area Index ◽  
Crop Establishment ◽  
Boro Rice

Physiological attributes and yield performance of high yielding varieties (HYV) of rice cultivars need to be assessed by crop establishment methods before promoting a suitable crop establishment method in Bangladesh. We, therefore, conducted an experiment to study the effects of crop establishment methods on the growth and yield of boro rice. The experiment comprised of two factors; factor A: methods of crop establishment viz., dry direct seeding, unpuddle transplanting, alternate wetting and drying (AWD) and puddle transplanting; factor B: rice cultivars viz., BRRI dhan28, BRRI dhan58, BRRI dhan74 and BRRI hybrid dhan3. The experiment was laid out in a split-plot design with three replications where method of crop establishment was assigned to the main plot and rice cultivar was assigned to the sub plots. Data were collected at different growth stages and at harvest. From the results, it was found that growth, yield and yield contributing characters were significantly influenced by crop establishment methods. The highest leaf area index (LAI), total dry matter and grain yield were found in puddle transplanting method. The highest grain yield was obtained in puddle transplanting method due to accumulation of maximum dry matter and production of highest number of effective tillers hill-1 and grains panicle-1. Among the varieties the highest grain yield was obtain in BRRI hybrid dhan3 due to highest number of grains panicle-1 and 1000-grain weight. The highest grain yield (6.21 t ha-1) was found in puddle transplanting with BRRI dhan28, while the lowest grain yield (2.80 t ha-1) was produced in dry direct seeding with BRRI dhan28. Therefore, puddle transplanting with BRRI dhan28 might be recommended due to best physiological performance and obtaining highest grain yield of boro rice.

STEGANOGRAFI DENGAN MENGGUNAKAN METODE LSB DAN ALGORITMA HILL CIPHER

2017 ◽  
Vol 1 (1) ◽  
Author(s):  
Sherly Gina Supratman
Keyword(s):  
Digital Images ◽  
Text Messages ◽  
The Internet ◽  
Digital Imagery ◽  
Least Significant Bit ◽  
Hill Cipher ◽  
Secure Data ◽  
Audio Video ◽  
The Hill

AbstrakJaringan Komunikasi seperti Internet� merupakan jaringan yang tidak aman untuk mentransmisi data, seperti teks, audio,video dan citra digital. Salah satu cara untuk pengamanan data dapat dilakukan dengan menggunakan proses kriptografi dan �steganografi. Penggunaan ini dengan tujuan untuk merahasiakan pesan yang dikirim dan sekaligus menghindarkan pesan tersebut dari kecurigaan pihak lain yang tidak berkepentingan.Pesan yang digunakan dalam makalah ini adalah berupa text dengan menyisipkannya pada gambar. Pada proses kriptografi, pesan yang berupa text akan dienkrip dengan algoritma Hill Chiper, dan kemudian pesan yang telah dienkrip akan dilakukan proses steganografi pada citra digital� 8 bit dengan skala 0 � 255, dengan metode Least Significant Bit ( LSB ).�Kata kunci: Kriptografi, Hill Chiper, Steganografi, Least Significant Bit�AbstractCommunication Networks such as the Internet are unsafe networks for transmitting data, such as text, audio, video and digital imagery. One way to secure data can be done by using cryptography and steganography process. This use is for the purpose of concealing messages being transmitted and avoiding such messages from the suspicion by others who are not interested.The message used in this paper is text by inserting it in the image. In the cryptographic process, text messages will be encrypted with the Hill Chiper algorithm, and then the encrypted message will be steganographed on 8-bit digital images on a scale of 0-255, using the Least Significant Bit (LSB) method.�Keywords: Cryptography, Hill Chiper, Steganography, Least Significant Bit

Hyperspectral characteristics and leaf area index monitoring of rice (Oryza sativa L.) under carbon dioxide concentration enrichment

2021 ◽  
Vol 54 (3) ◽  
pp. 231-243
Author(s):  
Chao Liu ◽  
Zhenghua Hu ◽  
Rui Kong ◽  
Lingfei Yu ◽  
Yuanyuan Wang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Oryza Sativa ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Oryza Sativa L ◽  
Carbon Dioxide Concentration ◽  
Area Index

Detection of Yellow Hawkweed (Hieracium pratense) with High Resolution Multispectral Digital Imagery

1995 ◽  
Vol 9 (3) ◽  
pp. 477-483 ◽  
Author(s):  
Hubert W. Carson ◽  
Lawrence W. Lass ◽  
Robert H. Callihan
Keyword(s):  
Supervised Classification ◽  
Digital Images ◽  
Ground Cover ◽  
Unsupervised Classification ◽  
Digital Imagery ◽  
Charge Coupled Device ◽  
Spectral Filters ◽  
A Charge ◽  
Northern Idaho

Yellow hawkweed infests permanent upland pastures and forest meadows in northern Idaho. Conventional surveys to determine infestations of this weed are not practical. A charge coupled device with spectral filters mounted in an airplane was used to obtain digital images (1 m resolution) of flowering yellow hawkweed. Supervised classification of the digital images predicted more area infested by yellow hawkweed than did unsupervised classification. Where yellow hawkweed was the dominant ground cover species, infestations were detectable with high accuracy from digital images. Moderate yellow hawkweed infestation detection was unreliable, and areas having less than 20% yellow hawkweed cover were not detected.

scholarly journals Optimizing smartphone-based canopy hemispherical photography

2021 ◽  
Author(s):  
Gastón Mauro Díaz
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Accuracy Assessment ◽  
Low Cost ◽  
R Package ◽  
Coefficient Of Determination ◽  
Native Forest ◽  
Hemispherical Photography ◽  
Area Index ◽  
Plant Area Index

1) Hemispherical photography (HP) is a long-standing tool for forest canopy characterization. Currently, there are low-cost fisheye lenses to convert smartphones into high-portable HP equipment; however, they cannot be used whenever since HP is sensitive to illumination conditions. To obtain sound results outside diffuse light conditions, a deep-learning-based system needs to be developed. A ready-to-use alternative is the multiscale color-based binarization algorithm, but it can provide moderate-quality results only for open forests. To overcome this limitation, I propose coupling it with the model-based local thresholding algorithm. I call this coupling the MBCB approach. 2) Methods presented here are part of the R package CAnopy IMage ANalysis (caiman), which I am developing. The accuracy assessment of the new MBCB approach was done with data from a pine plantation and a broadleaf native forest. 3) The coefficient of determination (R^2) was greater than 0.7, and the root mean square error (RMSE) lower than 20 %, both for plant area index calculation. 4) Results suggest that the new MBCB approach allows the calculation of unbiased canopy metrics from smartphone-based HP acquired in sunlight conditions, even for closed canopies. This facilitates large-scale and opportunistic sampling with hemispherical photography.

scholarly journals Implementasi Pengamanan Citra Digital Menggunakan Algoritma ICE

2020 ◽  
Vol 1 (3) ◽  
pp. 284
Author(s):  
Josua Alfiandi Sinuhaji
Keyword(s):  
Digital Image ◽  
Block Cipher ◽  
Digital Images ◽  
Source Code ◽  
Digital Imagery ◽  
The Subject ◽  
Data Theft ◽  
The Difference ◽  
Cryptographic Techniques ◽  
Rotation Function

Digital imagery is currently very widely used, so it is very vulnerable to data theft by unauthorized parties. In order to maintain the security of digital images can be done by using cryptographic techniques. Cryptographic techniques can encode digital images by encrypting them in the form of passwords that are not understood. ICE is a block cipher published by Kwan in 1997. This algorithm has a structure similar to DES, but with additional bit permutations that do not depend on the key in the rotation function. There are various types of ICE variants, namely Thin-ICE, ICE standard, and ICE-n. The difference between the three is the length of the keyword used and the number of rounds. The Thin-ICE algorithm uses 64 bits and 8 turns. The ICE standard uses 64 bits and 16 round keys. The ICE-n algorithm uses keys 64n bits and 16n turns. The use of this type of algorithm can be adjusted to the needs of users where Thin-ICE has the lowest level of security among the three, while ICE-n is the highest. This algorithm does not become the subject of a patent and the source code can be used freely.Keywords : Cryptography, Digital Image,Algorithm,ICE.

scholarly journals AVALIAÇÃO DE TRÊS MÉTODOS DE OBTENÇÃO DO ÍNDICE DE ÁREA FOLIAR PARA CULTURA DA SOJA

Nativa ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 284
Author(s):  
Ana Laura Pereira Souza ◽  
Marcelo Marques Costa ◽  
Darly Geraldo de Sena Junior ◽  
Rogério Borges de Oliveria Paz
Keyword(s):  
Leaf Area ◽  
Plant Density ◽  
Digital Images ◽  
Block Design ◽  
Linear Equations ◽  
Density Variation ◽  
Imaging Method ◽  
Area Index ◽  
Soybean Crop ◽  
Randomized Block Design

O Índice de área foliar (IAF) representa a eficiência na interceptação e utilização da radiação solar pelas plantas. O IAF pode ser obtido de forma direta, determinando-se a área foliar e área ocupada pela planta. Entretanto, métodos indiretos são comumente utilizados para sua estimativa devido a necessidade de praticidade. O objetivo deste trabalho foi avaliar a equivalência das estimativas do IAF obtidas por meio de um ceptômetro, pelo método de discos e utilizando imagens digitais. Para tanto, foi conduzido um experimento com a cultura da soja, no delineamento em blocos casualizados, com variação da densidade de plantas, para comparar os valores de IAF obtidos pelos diferentes métodos aos 34 dias após a semeadura (DAS). A comparação foi feita por meio dos coeficientes de equações lineares ajustadas entre os resultados obtidos. O método do disco e do ceptômetro, apresentaram uma boa equivalência entre seus valores. Entretanto, o método que utiliza imagens superestimou o IAF, não apresentando uma boa equivalência de seus valores aos do método de discos e ao ceptômetro.Palavras-chave: ceptômetro, discos foliares, imagens digitais. EVALUATION OF THREE OBTAINMENT METHODS OF FOLIAR AREA INDEX FOR SOYBEAN CROP ABSTRACT:The leaf area index (LAI) represents the interception efficiency and use of solar radiation by plants. IAF can be obtained directly, determining the leaf area and area occupied by the plant. However, indirect methods are commonly used for their estimation because for practicality. The objective of this work was to evaluate the equivalence of the LAI estimates obtained with a ceptometer, using the disc method and digital images. A experiment was conducted with soybean crop, in a randomized block design with plant density variation to compare the LAI values obtained by the different methods at 34 days after sowing (DAS). The comparison was made through the coefficients of linear equations adjusted between the results obtained. The disc and the ceptometer method presented a good equivalence between their values. However, the imaging method overestimated the LAI, not presenting a good equivalence of its values to those of the disc method and the ceptometer.Keywords: ceptometer, leaf discs, digital images.

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