X-ray based seed analysis and sorting - ISTA Online · PDF fileX-ray based seed analysis and...
Transcript of X-ray based seed analysis and sorting - ISTA Online · PDF fileX-ray based seed analysis and...
X-ray based seed analysis and sorting
Drs. Henry Bruggink
INCOTEC
Outline
• Background – the discovery of X-rays• Visualisation of X-rays• X-rays and seed analysis• Sorting for seed quality• Present and Future
X-Rays
Discovery of X-rays
• 1895: Dr. Wilhelm Conrad Röntgen produced radiation with an experimental electrical discharge tube: X-rays
• made photographs of “invisible” structures• 1st Nobel Prize in Physics, 1901• Father of diagnostic radiology (Medicine)• Nowadays also for Non-Destructive Testing,
airport control, crystallography, etc.
Creating a visible image
X-rays: electromagnetic radiation, 0.01 to 10 nmRöntgen used a screen of barium platinocyanide: X-ray photons are converted into light fluorescenceLater: photographic plates, filmsDisadvantages:
HP Faxitron
− long exposure times− development time− not reuseable− analogue medium
From analogue to digital radiography
Nowadays, most detectors are based on a scintillator: ionizing radiation light (fluorescence)• Image Intensifier (scintillator + photo multiplier) +
digital camera• Scintillator + photodiodes:
– Flat panel detector– Line scan camera– CCD (charge coupled device) based detector
Detectors: Image Intensifier
Input screen
PhotokathodeNa-activated CsI
Aluminum layer
Output screen
Glass window
High resolution digital camera
Digital detectors
• Flat Panel Detector– Indirect: scintillator emits
light that is captured by photodiode and translated into electrical signal
– Direct: compound (e.g. Selenium) that emits electrons when hit by X-ray photon
From Varian: PaxScan Flat panel X-ray Imaging
Digital detectors
• Line scan camera– Single line scans over
object; high energy needed– TDI (Time Delay
Integration): more lines, giving high resolution and high sensitivity
• CCD camera– Scintillator coupled to CCD
chip with fiber optics
From Hamamatsu: X-ray Line Scan Camera C10400
From Hamamatsu: X-ray Camera with Fiber Optics Window
Analysis of seeds using X-ray
The first to use X-rays for seed analysis was Lundström (1903): coniferous tree seeds
Advantages are obvious:– information on structure and condition of embryo– and on presence of insects, diseases or other defects– content of fruits (e.g. multigerm)– much faster than germination test (esp. tree seeds)
X-ray contrast method: contrasting agent dead tissue
Analysis of seeds using X-ray
Many species have been investigated of all kinds: trees, vegetables, agronomic crops, …
Haff & Slaughter (2004)
Stark & Adams (1963)
Kamra (1976)
For sugar beet: routinely used tool for cleaning and upgrading
Tomato seed
Tomato seed (W-Eur): high value, high requirements: Useable Transplants (UT) = normal, uniform size
too small: not Useable
From analysis to sorting
Van der Burg et al. (1994) - X-ray images give information– embryo size and morphology – the amount of endosperm– the area of free space
X-ray analysis can predict seedling performance (% UT) and enable the selection of high-quality seed
This lead to an initiative of Dutch companies, to develop and build an X-ray sorting system for tomato seed
Research at Incotec
Categorization of tomato seeds, imaged on film, using various parameters:
– embryo size – embryo shape– endosperm– free space– tissue density– …..(1994)
The importance of priming
• Without priming, in general poor visibility of internal structures (no free space)
• Not all primings result in good visibility!
• And: priming brings potential of a seed to expression – uniform germination– relieve of dormancy Non-primed Primed
System development
• Economically feasible: minimum capacity• Started in 1996, prototype in 2007 to Production
Some aspects• Detector:
− Flat scan: more seeds in one imageImage Intensifier
• Transport system: tray with several grids• Software:
– image processing– classification
Problem: huge variation
Variation in tomato seed
• Different grey values per seed lot: optimize settings• No consistent correlation between image and seedling
quality over various lots Intake test for each seed lot:
– make images of 800 seeds– determine seedling quality of these seeds– make correlation– make prognosis: expected amount, quality of fractions– input customer– instruct software
Sophisticated analysis software, various options
Results
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Primed seed
Option 1Option 2Option 3
Perc
enta
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Upgrading options
UT in fractiion Q1
Output
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Primed seed Q1 Q2 Q3
Use
able
Tra
nspl
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(%)
Tomato: effect on Useable Transplants (n=10)
Greenhouse 25 °C, 11d after sowing
Primed seed Q1 Q2 Q3UT1 74%Fraction wht 100%
89%36%
66%45%
41%19%
Limitations of X-ray sorting
• Speed: limited capacity, only for high value seeds
• Note: larger seed size means lower capacity
• Only for flat seeds: always positioned in the same plane
• Only information on morphology, not on physiology
3N WatermelonTomato
X-ray analysis and sorting: present & future
Analysis of seeds• Digital systems are well available• Possibility to enlarge images (more info per seed)• Various developments in analysis software• 3D analysis
Sorting of seeds• Incotec will only provide services, not machines• and will expand to pepper and more crops• Developments at machine builders: systems will become
available for seed companies
Thank you for your attention
Risk of damage by X-ray
For making images of seeds: low energy (“soft”) X-raysSeveral studies: no genetic or physiological effects
0%
20%
40%
60%
80%
100%
original seed Faxitron: 12.5kV,
3.4mA, 3min
Faxitron: 25kV, 3.4mA,
3min
Faxitron: 50kV, 3.4mA,
1min
Faxitron: 50kV, 3.4mA,
3min
Yxlon: 12.3kV, 3.4mA, 10s
Yxlon: 25kV, 6mA, 10s
Effect of various X-ray doses on the GH germination of primed tomato seed
Not
Abn.
UT2
UT1
Upgrading of pepper seed
For pepper: similar results as for tomato
0.0
20.0
40.0
60.0
80.0
100.0
Primed seed Q1 Q2 Q3
Use
able
Tra
nspl
ants
(%)
Pepper: effect on Useable Transplants (n=12)