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AutoCAD autoModellenCFDSystembuild

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Applying new visualization techniques to construct 3-D geometrical plant models

B. Nicolaï

University of Leuven - Belgium

Antoni van Leeuwenhoek1632-1723

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Techniques• X-ray (micro) Computed Tomography• Magnetic Resonance Imaging (MRI)• Neutron tomography• Confocal microscopy( CLSM)• Optical coherence tomography (OCT)• Ultrasound tomography• …

X-ray tomography: principle X-ray generation

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http://www.celnav.de/hv/hv5.htm

Detection of X-rays• Photographic plate• Geiger counters• Scintillators

o Materials such as NaI convert X-ray photon to VIS photon

o VIS photon amplified using photomultiplier• Scintillator screens

o Imaging using line or CCD camera

Interaction with matter• Absorption depends on

o Compositiono Sizeo Energy level

• Beer’s law

with I : intensity of beam at position x

I0 : intensity of beamμ : linear attenuation coefficient

0 exp( )I I xμ= −

I

I0

x

3-D reconstruction

Intensity

3-D reconstruction

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3-D reconstruction

Intensity

+ + = Reconstruction

Real

Types of X-ray equipment• Radiography (2D)• CT scanners (3D)• X-ray computed micro-tomography (3D > 1μm)• Synchrotron radiation X-ray tomography (3D < 1μm)

Examples of (μ)CT• CT images obtained with medical CT scanner

o Fast scan times !o Low res

Els Herremans, unpublished

• Changes of internal air space during fruit development

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• Vascular system in apple • Disorders in apple during commercial storage

Braeburn browning disorder Verde doncella watercore

Nov. Dec. Jan. W.coreSound

Herremans et al. (2013) Postharvest Biol. Technol. 75

ESRF (France)

sample

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Verboven et al. Plant Physiol. 2008;147:518-527

Apple Pear

140 μm

• Individual apple cello Purple: cello Yellow: air space

300 μm

Pear Apple

• Rice stem

Complete image of an internode (nodes are indicated with the arrows)

Image of the aerenchymachannels (blue) and spongy tissue (cyan) across the internode

Detail of the aerenchyma (blue) and spongy tissue (cyan) at a node

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Central cavities (blue) in the internodes

Spongy tissue (cyan) in the node

Stem aerenchyma (blue) connecting with spongy 

tissue (green) of internode

Geometric macroscale models

Geometric microscale models

Mebatsion et al. (2009) Journal of Food Engineering 93 (2009) 141–148

Geometric model (pear parenchyma) Synchrotron microtomography

Geometric model (pear intercellular space)

Synchrotron microtomography

Mebatsion et al. (2009) Journal of Food Engineering 93 (2009) 141–148

Cell growth models

Parenchyma tissue Intercellular space

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symplast + cell wall air space pear cortex+ =

Virtual skin apple tissue Synchrotron tomography of apple skin tissue

Application: gas transport in apple

Ho et al. (2008) PLoS Comp Biol 4 (3), art.nr. e1000023, -.Ho et al. (2011) Plant Phys 155 (3), 1158-1168

Conclusions• 3-D essential for certain geometrical features• X-ray micro and nano CT perfect for micrometer resolution

3-D imaging• Submicron resolution now possible with benchtop micro CT• Synchrotron CT necessary when fast imaging, very high

resolution or phase contrast imaging is required• Image processing very time consuming• Reconstructed images basis for engineering computations

Acknowledgements• Metadel Abera• Thijs Defraeye• Els Herremans• Hibru Mebatsion• Quang Tri Ho• Maarten Hertog• Pieter Verboven

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'What is the use of a book', thought Alice, 'without pictures or conversations?'

LEWIS CARROLL, Alice in Wonderland