Estimation of the height and angles of orientation of the upper leaves in the maize canopy using stereovision

Ivanov, N.; Boissard, P.; Chapron, M.; Valéry, Pierre

doi:10.1051/agro:19940305

Cited by 20 publications

(10 citation statements)

References 3 publications

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“…We open this discussion with a review of previous measurement techniques used to describe the geometry of grasses, beginning with the methodology presented by Bonhomme and Varletgrancher (1978 More recently, Biskup et al (2007) developed their own stereo imaging system and showed its applicability by digitizing the upper layer soybean canopy leaves covering an area of 1.20 by 0.80 meter. The idea is similar to that of Ivanov et al (1994), where two photographs from the canopy are simultaneously taken and corresponding points on each picture are matched, allowing the estimation of their coordinates. The great improvement introduced by this technique is the automatic marking and matching of points, which greatly hastens the process of digitally constructing the plant.…”

Section: Introductionmentioning

confidence: 99%

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Understanding the partitioning of rainfall by the maize canopy through computational modelling and physical measurements

Frasson¹

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The interception and redirection of rainfall by vegetation has implications for many fields such as remote sensing of soil moisture, satellite observation of rainfall, and the modeling of runoff, climate, and soil erosion. Although the modeling of rainfall partitioning by forests has received attention in the past, partitioning caused by crops has been overlooked. The present work proposes a two front experimental and computational methodology to comprehensively study rainfall interception and partitioning by the maize canopy.In the experimental stage, we deployed two compact weather stations, two optical disdrometers, and five tipping bucket rain gauges. Two of the tipping bucket rain gauges were modified to measure throughfall while two were adapted to measure stemflow. The first optical disdrometer allowed for inspection of the unmodified drop-size and velocity distributions, whereas the second disdrometer measured the corresponding distributions under the canopy. This indicates that the outcome of the interaction between the hydrometeors and the canopy depends on the drop diameter.In the computational stage, we created a model that uses drop-size and velocity distributions as well as a three-dimensional digital canopy to simulate the movement of raindrops on the surfaces of leaves. Our model considers interception, redirection, retention, coalescence, breakup, and re-interception of drops to calculate the stemflow, throughfall, and equivalent height of precipitation stored on plants for a given storm.Moreover, the throughfall results are presented as two-dimensional matrices, where each term corresponds to the accumulated volume of drops that dripped at a given location.This allows insight into the spatial distribution of throughfall beneath the foliage. Finally, we examine the way in which the maize canopy modifies the drop-size distribution by recalculating the drop velocity based on the raindrop's size and 2011 All Rights Reserved Graduate College ii To my parents Mirian and Deodoro Frasson and my lovely wife iii ACKNOWLEDGMENTS During my studies at The University of Iowa, I have worked with an amazing array of people, from whom I have learned a wide variety of professional and interpersonal skills. I would like to begin by acknowledging the support, encouragement, and guidance of Professor Witold Krajewski, who made this thesis possible. In addition to the scientific skills that Professor Krajewski taught me, he showed me how to balance my professional and personal lives, how to focus on a task and see it to fruition, and how to maintain sight of where my work fits into the big picture. He improved my ability to present my work and taught me the difference between a poster and a paper.

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Section: Introductionmentioning

confidence: 99%

“…As the distance between cameras is known, the positions of the points can be calculated from the rectified images. The rectification process depends on parameters that are unique to the photography setup and that are determined through calibration Ivanov et al (1994). describe an application of stereo-photography in the reconstruction of a maize canopy.…”

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Understanding the partitioning of rainfall by the maize canopy through computational modelling and physical measurements

Frasson¹

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“…Kise and Zhang (2008) used a stereo system for crop rows detection. Ivanov et al (1994) applied stereo vision to study the leaf angle and area in a maize canopy. Müller-Linow et al (2015) have tested stereo-imaging on sugar beet in natural conditions.…”

Section: Introductionmentioning

confidence: 99%

Imaging Wheat Canopy Through Stereo Vision: Overcoming the Challenges of the Laboratory to Field Transition for Morphological Features Extraction

et al. 2020

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Stereo vision is a 3D imaging method that allows quick measurement of plant architecture. Historically, the method has mainly been developed in controlled conditions. This study identified several challenges to adapt the method to natural field conditions and propose solutions. The plant traits studied were leaf area, mean leaf angle, leaf angle distribution, and canopy height. The experiment took place in a winter wheat, Triticum aestivum L., field dedicated to fertilization trials at Gembloux (Belgium). Images were acquired thanks to two nadir cameras. A machine learning algorithm using RGB and HSV color spaces is proposed to perform soil-plant segmentation robust to light conditions. The matching between images of the two cameras and the leaf area computation was improved if the number of pixels in the image of a scene was binned from 2560 × 2048 to 1280 × 1024 pixels, for a distance of 1 m between the cameras and the canopy. Height descriptors such as median or 95th percentile of plant heights were useful to precisely compare the development of different canopies. Mean spike top height was measured with an accuracy of 97.1 %. The measurement of leaf area was affected by overlaps between leaves so that a calibration curve was necessary. The leaf area estimation presented a root mean square error (RMSE) of 0.37. The impact of wind on the variability of leaf area measurement was inferior to 3% except at the stem elongation stage. Mean leaf angles ranging from 53°to 62°were computed for the whole growing season. For each acquisition date during the vegetative stages, the variability of mean angle measurement was inferior to 1.5% which underpins that the method is precise.

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“…Electromagnetic tracking instrument is a kind of digital measuring tools based on electromagnetism [3]. It is an effective tool of getting structure data of fruit trees because it is not only an easy-to-use, extremely accurate and broad action sphere device but also a powerful survey tool which can track the space track and calculate the inclination angle of stylus [2].…”

Section: Introductionmentioning

confidence: 99%

A Method to Calibrate the Electromagnetic Tracking Instrument When Measuring Branches of Fruit Trees

Wu¹,

Jian²,

Zhou³

et al. 2011

Computer and Computing Technologies in Agriculture IV

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To reduce the effect from instrument error when getting characteristic parameters of branches of fruit trees by the electromagnetic tracking instrument, a calibration method was sounded based on a discussion of the instrument error of electromagnetic tracking instrument. Finally, the method was tested in an experiment. By comparing the data of the experiment and the standard data which was got by slide caliper, we proved that the method is effective in increasing the accuracy of measurement.

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Estimation of the height and angles of orientation of the upper leaves in the maize canopy using stereovision

Cited by 20 publications

References 3 publications

Understanding the partitioning of rainfall by the maize canopy through computational modelling and physical measurements

Understanding the partitioning of rainfall by the maize canopy through computational modelling and physical measurements

Imaging Wheat Canopy Through Stereo Vision: Overcoming the Challenges of the Laboratory to Field Transition for Morphological Features Extraction

A Method to Calibrate the Electromagnetic Tracking Instrument When Measuring Branches of Fruit Trees

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