Multispectral Imaging of Grains and Seeds with VideometerLab 3

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VideometerLab 3 Multi-Spectral Imaging System

MSI for Grain and Seed Analysis

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Traditional colour imaging uses three broad bands of colour:

Red, Green and Blue

Normal Colour Imaging

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Normal Colour Imaging

• RGB photographs have limited spectral resolution

• Chlorophyll a and b give almost the same RGB signal and are not spectrally separated

Chloro-a High Low High

Chloro-b High Low High

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Multispectral Imaging

Chloro-a High Low Low High

Chloro-b Med High Med Low

• Using just 4 wavelength bands with tightly defined ranges, Chlorophyll a and b can easily be distinguished

• VideometerLab 3 uses 19 wavelength bands

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Multispectral Imaging

• Many images obtained at selective wavelength bands

• Each image pixel contains spectral data points

• Spectral signature reveals chemo-specific information

• See spatial location of surface chemical variation

Ultraviolet Near-Infrared

Infra-Red Red Yellow Green Blue Ultra-Violet

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VideometerLab 3 Schematic

• Narrowband illumination provided by 19 LEDs between 375nm-970nm (UV-Vis-VNIR)

• Integrating sphere diffuses light onto sample

• 2056x2056 CCD camera captures reflectance at each LED wavelength for each pixel

• Emission filter wheel for longpass/bandpass filtering

• Bright-field or dark-field lighting for translucency or diffuse scatter imaging

Camera

LEDs

Integrating sphere

Emission filter wheel

Sample

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VideometerLab 3 Schematic

• Precise lighting control for optimal illumination of each sample across whole spectrum

• Diffuse light on sample ensures even lighting from all directions

• Broadband camera spectrally and spatially calibrated (NIST)

• Emission filters enable multispectral reflectance and fluorescence imaging abilities

• Powerful, user-friendly image analysis and quantification software for data and modelling

Camera

LEDs

Integrating sphere

Emission filter wheel

Sample

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VideometerLab 3 Schematic

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MSI Analysis Process

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• The VideometerLab identifies the spectral signature of these sesame seeds

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MSI Analysis Process

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• The VideometerLab identifies the spectral signature of these sesame seeds

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MSI Analysis Process

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• It will then identify that there is something not matching the ‘sesame seed’ spectral signature in this mix

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MSI Analysis Process

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• It will then identify that there is something not matching the ‘sesame seed’ spectral signature in this mix

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MSI Analysis Process

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• Magnification of the previous image

1mm

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• A false colour image to aid visual assessment of chitting is simply four clicks of the mouse

Chitting

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• The dark spots on the right image are the beginning of the germination

Chitting

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• They can also be counted and analysed quantitively very easily. The image on the left has highlighted only areas of chitting

Chitting

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• Alternatively, the ratio of germinating to non-germinating seeds could be measured automatically

Chitting

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• The same types of analysis can be applied to rootlets

Rootlets

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• Acrospire modeling compares the length of the acrospire with the length of the seed, and in contrast to other methods only requires boiling the seed in water for ten minutes

Acrospire Length

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• Methods of estimating the ratio of embryo to husk in grist are time consuming

Grist \ Draff

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• The Videometer can tell between embryo and husk with almost perfect clarity in less than ten seconds

Grist \ Draff

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• The Videometer can quantify the important information clearly and precisely

Grist \ Draff

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Husk Area (mm2) Embryo Area (mm2) Ratio

3068 230 13.3

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• By masking out all non-data from an image, the Videometer can distinguish long, thin Durum from short, fat Mascot grains

Variety - Geometric

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• The table to the right shows some of the data which the Videometer uses to classify this mixed sample

Variety - Geometric

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• Alternatively, the Videometer can use spectral data to distinguish between UV-absorbent Optic (left) and UV-reflectent Concerto (right)

Variety - Spectral

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• The ‘redder’ a grain, the more likely it is to be Optic and the ‘bluer’ the more likely Concerto. The background has been arbitrarily coloured red

Variety - Spectral

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• This can also be quantified. In a real setting, you would use both spatial and spectral data to get the most accurate discrimination possible

Variety - Spectral

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Really… % Similarity Optic

% Similarity Concerto

Optic

97.25

2.75

Concerto

1.25

98.75

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• By teaching the Videometer the difference between a skinned and intact grain, it can instantly replace a labour-intensive application by quantifying the percentage of skinned grains

Skinning

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• Some details from the last slide

Skinning

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• Some of these grains have strange black tips, highlighted in the image on the right

Anomaly Analysis

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• Detail of the previous slide

Anomaly Analysis

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• This slide shows a quantification of the differences in the ultra-blue band between ‘normal grain’ and ‘black tip’

Anomaly Analysis

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• This graph is the full spectrum for the ‘normal grain’ (the two blue lines) and the ‘black tip’ (the red line), clearly showing the difference

Anomaly Analysis

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• This slide demonstrates how a false-colour image of fusarium-infected grains can help an operator determine the extent of the infection

Fusarium

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• A more systematic model has been developed by Videometer (in collaboration with the Carlsberg Research Institute) showing an impressive R2 value of 0.85 versus real-time PCR

Fusarium

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• Though the Videometer is a surface technique, it can quantify levels of hydration in grain with a small amount of sample preparation. Light blue areas are not hydrated

Hydration

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The Videometer is an excellent tool for many grain and seed applications, and can be used throughout the quality control and R&D cycle – from raw material intake to final product QC and lab analysis

Videometer can perform other roles too. If a feasibility study such as those shown here interest you, my contact details are on the next slide

Conclusions

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Contact

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analytikLtd

Adrian Waltho – Sales Specialist

Tel: +44 (0)870 991 4044 Fax: +44 (0)870 135 2488 Email: adrian.waltho@analytik.co.uk

Barn B, 2 Cygnus Business Park, Middle Watch, Swavesey, Cambridgeshire, CB24 4AA

www.analytik.co.uk