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X-Ray for Agricultural Applications. Dave Utrata Iowa State University Center for NDE IPRT Company Assistance – NDE Group Alexandra Black, Brett Barnes Iowa State University. Three Rivers Technical Conference Elk River, MN August 3-4, 2010. Presentation Outline.
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X-Ray for Agricultural Applications Dave Utrata Iowa State University Center for NDE IPRT Company Assistance – NDE Group Alexandra Black, Brett Barnes Iowa State University Three Rivers Technical Conference Elk River, MN August 3-4, 2010
Presentation Outline • Background of Company Assistance program • Current efforts, interests • Review of progress in three areas • Detection of frost damage in maize seeds • Distinguishing between haploid/hybrid condition in corn seeds • Imaging of root development • Summary • Applications, potential, challenges Three Rivers Tech Conf - 3-4 Aug 2010
Iowa State University – Institute for Physical Research and Testing IPRT Company Assistance • Technology Commercialization - accelerate commercialization of ISU and company-developed technology through research and development assistance. • Technical Assistance - provide short-term, no-cost technical assistance to Iowa companies in materials and nondestructive evaluation. Three Rivers Tech Conf - 3-4 Aug 2010
Operational Guide – NDE Group • Explain & demonstrate the principles of various inspection methods • Perform feasibility studies to determine which NDE method will work best for your application • Develop inspection protocol for new designs or evaluate current inspection procedures • Provide information on sources of equipment, testing laboratories Help manufacturers become educated consumers of NDE Three Rivers Tech Conf - 3-4 Aug 2010
Beyond the usual suspects of fabricated metal, joining operations, current NDT practitioners… “Round up the usual suspects” Three Rivers Tech Conf - 3-4 Aug 2010
Nontraditional applications of NDE • Detection of frost damage in maize (corn) seed – Seed Science Institute, ISU • Distinguishing between haploid v. hybrid conditions in corn – Agronomy Dept. ISU • Visualizing root growth – North Central Regional Plant Introduction Station Three Rivers Tech Conf - 3-4 Aug 2010
Detection of frost damage in seed Three Rivers Tech Conf - 3-4 Aug 2010
Brief background of some work in field • X-ray used to look into potential for characterizing seeds • Often adapted from medical systems, very often restricted to film • “Soft” x-rays • Feasibility of digital high speed evaluation demonstrated using industrial system with pattern recognition for sorting Three Rivers Tech Conf - 3-4 Aug 2010
Detection of frost damage in corn seed • Can x-ray methodologies provide useful assessment of seed structure, viability? • Use modern industrial equipment: microfocus X-ray tube, all digital imaging • Differentiate between control group (no frost damage) and damaged maize seeds (artificial frost cycle) • B37 inbred line, male parent IRF311, hybrid 3 • Moisture content at harvest 50% • Provide more rapid alternative to current sectioning & staining (tetrazolium) test Three Rivers Tech Conf - 3-4 Aug 2010
Results • Using Flat Panel • Seven samples from both control and frost damaged groups were examined Three Rivers Tech Conf - 3-4 Aug 2010
Control seeds Three Rivers Tech Conf - 3-4 Aug 2010
Frost damaged seeds Three Rivers Tech Conf - 3-4 Aug 2010
Qualitative difference apparent between groups – loss of internal structureNext: quantitative analysis of images to remove subjective evaluation Three Rivers Tech Conf - 3-4 Aug 2010
X-ray Luminance Profiles of Maize Seeds Method • Line profile used to see if there is a numerical difference in the luminance profiles between a control corn seed and a frost damaged seed Three Rivers Tech Conf - 3-4 Aug 2010
Trends • In general, the luminance profile of a good seed with no frost damage is more erratic then the smoother bad seed’s profile • This trend presumably reveals frost damage to internal seed structure Control Frost Damage Three Rivers Tech Conf - 3-4 Aug 2010
Further analyses ofmaize seed X-rays • The luminance profiles were exported to spreadsheets • Two methods were used to numerically separate the control from the frost damaged seeds • Large Difference • Large Slope Three Rivers Tech Conf - 3-4 Aug 2010
Analysis : Large Difference • In the profile shown here, there are 4 differences in the “valid” region (internal seed features) that are larger then the threshold. Valid Region Total Range 4 2 1 3 Large Difference Threshold Large Difference Threshold = (Scale Factor)*(Total Range) Three Rivers Tech Conf - 3-4 Aug 2010
Analysis : Large Slope • For example, the profile of this seed has 5 Large Slopes in the valid region. Valid Region 3 2 4 6 1 5 Three Rivers Tech Conf - 3-4 Aug 2010
Results : Large Difference • There are typically more “large differences” within radiographs of control seeds than for frost damaged seeds. Control Frost Damage Three Rivers Tech Conf - 3-4 Aug 2010
Results : Large Slope • There are more “large slopes” on average within radiographs of control seeds than for frost damaged seeds Control Frost Damage Three Rivers Tech Conf - 3-4 Aug 2010
Conclusions • The internal structure of maize seeds may be revealed using standard industrial radiographic equipment • The adverse effects of frost damage were observable in this small study, independent of seed knowledge or significant manipulation of test conditions Three Rivers Tech Conf - 3-4 Aug 2010
Problems with analysis • The threshold multiplier has to be adjusted to maximize the divergence in counts/core counts between averaged results for good and bad learning sets • .055 used initially, .038 probably better • Similarly, the large derivative threshold is chosen to maximize this difference • 10 used initially, 12 probably better • The “valid” region of interest was subjectively chosen Three Rivers Tech Conf - 3-4 Aug 2010
Positive modification (attempts) • Change source to detector distance • Magnified image • Structural variation seen in more detail over greater pixel count • Work at lower voltage (40 kV 25 kV) • Strive for contrast variation afforded by lower energies • More automated line profile placement • Remove subjective analysis Three Rivers Tech Conf - 3-4 Aug 2010
Control Frost New Seed Radiographs Three Rivers Tech Conf - 3-4 Aug 2010
Line Profiles Radiograph with Equator, Automatic & Manual Profiles Highlighted Auto 3 Manual Auto 2 Auto 1 Equator Frost – Saturday Three Rivers Tech Conf - 3-4 Aug 2010
Large Difference Results Summary Difference is not as clear as was earlier believed; faulty logic due to magnified image? Three Rivers Tech Conf - 3-4 Aug 2010
Large Slope Results Summary Difference is not as clear as was earlier believed; faulty logic due to magnified image? Three Rivers Tech Conf - 3-4 Aug 2010
Radiographic detection of frost damage • Differentiation is certainly possible • To what degree? • 50% moisture at frost is no big challenge • Algorithm/logic needs to be refined • Slope/difference thresholds need account for morphology changes over higher pixel count Three Rivers Tech Conf - 3-4 Aug 2010
Haploid & hybrid seeds • The inducing of haploid corn from which to generate more vigorous hybrid lines is desired • Currently takes six to eight generations of corn, or 3-4 years, to produce the inbred lines to cross for hybridization • Effective method for inducing haploids would reduce this time to one or two generations • Allow for the faster production of hybrid lines • Greater freedom to experiment with other seed attributes • Distinguishing between stained and unstained seeds (current method) takes a trained eye and much time • CT scans on seeds were performed • Embryos of the haploid seeds were ~7% smaller by volume than the hybrid seeds Three Rivers Tech Conf - 3-4 Aug 2010
Hybrid Haploid Comparison of Hybrid & Haploid Collections Three Rivers Tech Conf - 3-4 Aug 2010
Data Analysis Procedure • A section of the radiograph was selected and a histogram of that luminance data was generated • Two sections were analyzed for each sample: • 600 pixel diameter circle (not adequate) • Oval with 900 & 600 pixel major and minor radii Three Rivers Tech Conf - 3-4 Aug 2010
Haploid – Saturday – 600 x 900 pixel oval Three Rivers Tech Conf - 3-4 Aug 2010
Luminance profiles of Haploid and Hybrid Seeds Do lower luminance values reflect smaller embryos? Three Rivers Tech Conf - 3-4 Aug 2010
Results not definitive • Scatter in data may prove analysis to be hopelessly clumsy • Is data showing density/volumetric info of interest? • Placement/size of measurement area still problematic Three Rivers Tech Conf - 3-4 Aug 2010
Interest in observing root structure • Commercial system prohibitively expensive • What can be done? Three Rivers Tech Conf - 3-4 Aug 2010
Styrofoam HolderConfigured for two plants Three Rivers Tech Conf - 3-4 Aug 2010
30 kV • Energy: 30 kV • Current: 250 µA • Spot Size: Small • FPS: 1 • Window Average: 10 • Source to Detector Distance: 26” • Source to Sample Distance: ~24” Three Rivers Tech Conf - 3-4 Aug 2010
40 kV • Energy: 40 kV • Current: 250 µA • Spot Size: Small • FPS: 1 • Window Average: 10 • Source to Detector Distance: 26” • Source to Sample Distance: 20” Three Rivers Tech Conf - 3-4 Aug 2010
50 kV • Energy: 50 kV • Current: 200 µA • Spot Size: Small • FPS: 1 • Window Average: 10 • Source to Detector Distance: 26” • Source to Sample Distance: 20” Three Rivers Tech Conf - 3-4 Aug 2010
Images of “Sprout & Grow”with Bean & Pea plants • Energy: 25 kV • Current: 250 µA • Spot Size: Small • Window Average: 10 • Source to Detector Distance: 24” Three Rivers Tech Conf - 3-4 Aug 2010
Sprout & Grow Holder – Front View A pea and bean seed grown in water and Styrofoam beads in half of the container. Three Rivers Tech Conf - 3-4 Aug 2010
Sprout & Grow Holder – Rear View Three Rivers Tech Conf - 3-4 Aug 2010
Optical Image X-Ray Image Sprout & Grow Holder – Front View Three Rivers Tech Conf - 3-4 Aug 2010
Optical Image X-Ray Image Sprout & Grow Holder – Rear View Three Rivers Tech Conf - 3-4 Aug 2010
Conclusions • X-ray imaging of roots quite possible • Use Styrofoam beads, not standard growing media • Scale of imaging important • Subtle initial growth or large developed network Three Rivers Tech Conf - 3-4 Aug 2010
Overall conclusions • Digital radiography is powerful tool for nontraditional applications • Communication of needs, tradeoffs necessary • Content revealed v. inspection rate Three Rivers Tech Conf - 3-4 Aug 2010
Thank you Three Rivers Tech Conf - 3-4 Aug 2010