The Use of Early Season Multispectral Images for Weed Detection in Corn

Armstrong, Jon-Joseph Q.; Dirks, R D; Gibson, K. D.

doi:10.1614/wt-06-074.1

Cited by 14 publications

(11 citation statements)

References 39 publications

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“…1.14 cm by 1.14 cm) and 2.62 cm 2 , and 14.44 and 30.3 cm 2 of actual ground area, respectively in the corresponding images. Considering that the smaller GSD had the higher spatial resolutions, any of these spatial resolutions were noticeably higher than those obtained by Armstrong et al (2007), who used multispectral images from a piloted aircraft flying at a 300 m altitude in maize fields for weed detection in the early season.…”

Section: Johnsongrass Detection and Mapping As Affected By Spatial Anmentioning

confidence: 71%

“…The images captured by Armstrong et al (2007) from that altitude resulted in pixel resolutions that ranged from 12.1 (146.41 cm 2 of ground area) to 16.7 cm (278.9 cm 2 of ground area), depending on slight variances in the altitude of the aircraft. With those GSD, the reliable early weed patch detection was not achieved, and they concluded that refinements in the sensor spatial and spectral resolutions were necessary to increase the ability to successfully detect early season weed infestations; a specific suggestion was that enhancement could be provided with ground-based systems.…”

Section: Johnsongrass Detection and Mapping As Affected By Spatial Anmentioning

confidence: 99%

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Object-based early monitoring of a grass weed in a grass crop using high resolution UAV imagery

López‐Granados

Torres‐Sánchez

Castro

et al. 2016

Agron. Sustain. Dev.

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Sorghum halepense (johnsongrass) is a perennial weed with a vegetative reproductive system and one of the most competitive weeds in maize showing a spatial distribution in compact patches. When maize is irrigated, successive weed emergences occur in the early phenological phases of the crop, which require several herbicide applications. Our aim was to provide an accurate tool for an early detection and mapping of johnsongrass patches and delineate the actual surface area requiring a site-specific herbicide treatment based on the weed coverage. This early detection represents a major challenge in actual field scenarios because both species are in the Poaceae family, and show analogous spectral patterns, an extraordinarily similar appearance and a parallel phenological evolution. To solve this, an automatic OBIA (object-basedimage-analysis) procedure was developed to be applied on orthomosaicked images using visible (red-green-blue bands) and multispectral (red-green-blue and near infrared bands) cameras collected by an unmanned aerial vehicle (UAV) that flew at altitudes of 30, 60 and 100 m on two maize fields. One of our first phases was the generation of accurate orthomosaicked images of an herbaceous crop such as maize, which presented a repetitive pattern and nearly no invariant parameters to conduct the aerotriangulation. Here, we show that high-quality orthomosaicks were produced from both cameras and that they were able to be the first step for mapping the johnsongrass patches. The most accurate weed maps were obtained using the multispectral camera at an altitude of 30 m in both fields. These maps were then used to design a site-specific weed management program, and we demonstrated that potential herbicide savings ranged from 85 to 96 %. Our results showed that accurate and timely maps of johnsongrass patches in maize can be a key element in achieving sitespecific and sustainable herbicide applications for reducing spraying herbicides and costs.

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Section: Johnsongrass Detection and Mapping As Affected By Spatial Anmentioning

confidence: 71%

Section: Johnsongrass Detection and Mapping As Affected By Spatial Anmentioning

confidence: 99%

Object-based early monitoring of a grass weed in a grass crop using high resolution UAV imagery

López‐Granados

Torres‐Sánchez

Castro

et al. 2016

Agron. Sustain. Dev.

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“…Agricultural weeds are often patchily distributed within a field (Cousens and Mortimer, 1995) and local dispersal around the parent results in patches that persist over many years (Wilson and Brain, 1991). With increasing interest in ecological weed management and site-specific management, research is currently developing tactics and technologies to spray only dense patches of weeds ("patch spraying") and to leave other areas unsprayed (Andújar et al, 2011;Armstrong et al, 2007;Brown and Noble, 2005). The ability to predict the distribution of weeds could aid decisions on the spraying of weed patches, particularly where pre-emergence herbicides are to be used (Oriade et al, 1996;Paice et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

The effects of nitrogen and neighbouring crops on maturation and timing of seed dispersal in Hordeum spontaneum Koch. and Brassica kaber (DC.)

Taghizadeh¹,

Bahari²,

Behpouri³

2016

Aust J Crop Sci

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Reproductive development and then timing of seed dispersal in many weeds is positively correlated with intensity/availability of environmental resources. In this study, we investigated the effects of nitrogen availability and the type of the crop on timing of weed seed dispersal. Two agricultural weeds; wild barley (Hordeum spontaneum Koch.) and wild mustard (Brassica kaber (DC.)) were grown in wheat and oilseed rape crops under a range of nitrogen levels. H. spontaneum seeds that developed under no or low nitrogen levels (0 and 60 kg ha -1 ) reached their final maturation stage sooner than those that developed under high nitrogen levels (120 and 240 kg ha -1 ), resulting in an earlier seed dispersal (109 and 76 degree-days where grown in wheat and oilseed rape cropping systems, correspondingly). In all nitrogen levels, H. spontaneum seeds developed in wheat crop reached their maturation stage sooner, and were then dispersed sooner than those developed in oilseed rape cropping system. The results of this study could help growers to make the best decision on weed management through management of seed dispersal. High nitrogen application, for example, with an early harvest may mean that a significant proportion of seeds are taken up to the combine harvester traveling long distances as grain impurity. In contrast, low nitrogen application with a late harvest may result in the majority of seeds falling to the ground and increasing subsequent crop interference. Therefore, an infested crop should be harvested as early as possible to reduce the quantity of weed seeds entering the seed bank.

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“…As scouting for, and counting, weeds is time consuming (Timmermann et al, 2003;Wyse-Pester et al, 2002) some form of machine-based weed detection is necessary (Gerhards and Oebel, 2006). Weed detection can be performed using remote (Armstrong et al, 2007), optoelectronic (Blackshaw et al, 1998), UV-induced fluorescence (Longchamps et al, 2010) or digital imaging sensors (BurgosArtizzu et al, 2009;Panneton and Brouillard, 2009;Schuster et al, 2007). All of these techniques require weed/crop discrimination.…”

Section: Introductionmentioning

confidence: 99%