Projection pattern intensity control technique for 3-D optical measurement

Lu, Cunwei; Cho, Genki

doi:10.1364/opex.13.000106

Cited by 9 publications

(4 citation statements)

References 10 publications

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“…Lu and Cho (2005) proposed a pattern intensity control based on acquiring a fully illuminated image of the scene to adjust automatically to surface reflectance. Wu et al (2006) used reflectance ratios from two patterns and high dynamic range imaging.…”

Section: Overview Of Scene and Acquisition Material-related Problems mentioning

confidence: 99%

Weed detection in 3D images

2010

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Machine vision has been successfully used for mechanical destruction of weeds between rows of crops. Knowledge of the position of the rows where crops should be growing and the assumption that plants growing outside such positions are weeds may be used in such systems. However for many horticultural crops, the automatic removal of weeds from inside a row or bands of crops in which the weeds are mixed with plants in a random manner is not solved. The aim of this study was to verify that plant height is a discriminating parameter between crop and weed at early growth stages, as weeds and crops grow at different speeds. Plant height was determined by using an active stereoscopy technique, based on a time multiplexing coded structured light developed to take into account the specificities of the small scale scene, namely occlusion and thin objects, internal reflections and high dynamic range. The study was conducted on two carrot varieties sown at commercial density. Different weed species were present at the time of data acquisition. To accurately represent plant height taking into account the ground irregularities, a new parameter called 'corrected plant height' was computed. This parameter was the distance between plant pixels and the actual ground level under them obtained by fitting a surface and seen from a reconstructed point of view corresponding to a camera's optical axis perpendicular to the ridge plane. The overall classification accuracy without correction was 66% whereas it reached 83% by using the corrected plant height.

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Section: Overview Of Scene and Acquisition Material-related Problems mentioning

confidence: 99%

Weed detection in 3D images

2010

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“…In order to solve this problem, the proposed system performs adjustment of the stripe intensity distribution by multistage intensity control [10] based on the proportional control component as shown in Eq. (6).…”

Section: Projection Pattern Intensity Controlmentioning

confidence: 99%

“…In addition, we develop a practical automatic robust 3D measurement system using projection pattern intensity control for automatic adjustment of the pattern intensity distribution to the surface reflection and color distribution of the measured object [10], and optimal intensity combination pattern projection to optimize the stripe intensity distribution [11].…”

Section: Introductionmentioning

confidence: 99%

“…As a step toward solving the above problems, in this paper we propose a method for automatic adjustment of the projection position and spatial frequency according to the size and location of the measured object. In addition, we develop a practical automatic robust 3D measurement system using projection pattern intensity control for automatic adjustment of the pattern intensity distribution to the surface reflection and color distribution of the measured object [10], and optimal intensity combination pattern projection to optimize the stripe intensity distribution [11].…”

Section: Introductionmentioning

confidence: 99%

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A practical 3D measurement system based on projection pattern control techniques

Cho¹,

Lu²

2009

Elect Comm in Japan

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SUMMARYMost of the recent 3D image measurement methods have employed certain pattern projection techniques because of their higher reliabilities. Especially, the intensitymodulated technique can detect more stripe addresses by a single projection and therefore is very much expected for its practical use in the near future. The traditional techniques of this type, however, have encountered several serious problems where 3D measurements are difficult in sensitivity, speed and accuracy or fatally impossible for unknown objects. In order to solve these problems, we propose an automatic control technique of angle and space frequency of projection pattern. Furthermore, for security of measurement accuracy and measurement speed, projection pattern intensity control technique and optimal intensity-modulation projection technique are adopted in the proposal measurement system. By using the proposed technique the automatic 3D measurement intended for the geostationary objects and the swaying objects were realized in experimental results.

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Polarization Imaging in 3D Shape Reconstrucion

Garbat

Woźnicki

2014

Advances in Intelligent Systems and Computing

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Projection pattern intensity control technique for 3-D optical measurement

Cited by 9 publications

References 10 publications

Weed detection in 3D images

Weed detection in 3D images

A practical 3D measurement system based on projection pattern control techniques

Polarization Imaging in 3D Shape Reconstrucion

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