Videometer lab 3 multispectral imaging for rapid non destructive surface analysis
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© analytikLtd analytik Ltd VideometerLab 3 Multi-Spectral Imaging Rapid Non-destructive Surface Analysis Adrian Waltho, Analytik Ltd (Cambridge, UK) [email protected] www.analytik.co.uk/multispectral-imaging Light reflectance surface mapping for accurate measurement of colour, texture, shape, size and chemical composition
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VideometerLab 3 is a vision-based lab analyser designed for fast and accurate determination of surface colour, texture, shape, size and chemical composition. The easy-to-use system integrates illumination, camera, and computer technology with advanced digital image analysis and statistics. VideometerLab 3 provides a rapid assessment of uniform and non-homogeneous samples by combining information on all of the above parameters automatically in just a few seconds, requiring no sample preparation and leaving the sample intact. Using strobed LED technology VideometerLab 3 combines measurements at up to 20 different wavelengths into a single high-resolution multispectral image. Every pixel in the image is a spectrum and the system can include wavelengths outside the range detected by traditional RGB technology. Why use VideometerLab 3? Currently, the non-destructive investigation of materials with non-uniform colour and texture can be difficult, tedious and expensive. Conventional techniques such as NIR spectroscopy only measure a single point or average over a fixed area and do not give an objective overall assessment of visual quality. Hyperspectral imaging is a powerful analysis technique but is financially restrictive with current technology and can suffer from poor signal to noise ratios. Studies have shown that VideometerLab 3 is as accurate as a test panel with significantly higher repeatability, removing subjective judgement. Specific areas of special interest such as shape, size or texture can be studied automatically. The choice of illumination wavelength ensures each application can be optimised and using LEDs in the UV or NIR adds information not visible to the human eye. As an example, most objects are white or transparent in the NIR region, which allows for the separation of the colour and surface properties of the object. Key product features: • NIST-traceable calibration for absolute accuracy • Integrating sphere provides very homogeneous and diffuse illumination • Multispectral analysis in less than 6 seconds • Up to 19 spectral bands in the range 375nm to 970nm • Fluorescence option available • Black and white high resolution CCD camera (2056x2056 pixels) • Improved signal-to-noise ratio by individual and automated adjustments of light intensity in each wavelength band • Improved colour determination compared to traditional RGB technology • Increased stability due to strobed LED source technology
Transcript of Videometer lab 3 multispectral imaging for rapid non destructive surface analysis
© analytikLtd
analytikLtd
VideometerLab 3 Multi-Spectral Imaging
Rapid Non-destructive Surface Analysis
Adrian Waltho, Analytik Ltd (Cambridge, UK)
www.analytik.co.uk/multispectral-imaging
Light reflectance surface mapping for accurate measurement of colour, texture,
shape, size and chemical composition
© analytikLtd
• Nuanced, human-like analysis of heterogeneous samples
• Objective, accurate, repeatable measurements
• Non-destructive analysis allows further sample assay work
• No sample preparation is required
• Rapid data acquisition and analysis allows high throughput screening
Why use Multispectral Imaging?
• Hybrid between spectroscopy and imaging
• Allows rapid, accurate and reproducible analysis of spectral AND spatial features including shape, colour, texture, size, surface chemistry and chemical composition
• The flexibility of the VideometerLab software unlocks many different application possibilities with the same hardware
• Advanced signal processing and statistical analysis algorithms allow fast, objective, repeatable, non-destructive analysis of any heterogeneous surface
Multispectral Imaging with VideometerLab 3
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What makes the VideometerLab unique? • The VideometerLab 3 provides 90% of the
performance of a hyperspectral imaging system at a fraction of the cost
• VideometerLab’s patented LED illumination system ensures high signal to noise ratio across the UV-Vis-VNIR spectrum (375nm-970nm at spaced intervals)
• Hyperspectral systems use a broadband illumination source, with a fixed intensity at each wavelength. The detector sensitivity can’t be changed, forcing a compromise that doesn’t use the optimum sensitivity at any wavelength and results in poor signal to noise
• LED illumination allows precise control of lighting conditions at each chosen LED wavelength allowing tuneable optimised illumination for any given sample surface
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• CIELab colour quantification and sRGB simulation under specified lighting conditions
• Contaminant detection and identification
• Concentration distribution heterogeneity of pharmaceutical API in tablets
• Corrosion quantification and grading of machinery parts
• Agar plate colony counting of multiple species simultaneously
• Forensic analysis of fingerprints, bloodstains, inks, powder residues and questioned documents
• Grain hydration and viability scoring
Multispectral Imaging Application Examples
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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
Many images obtained at many different wavelengths
Ultraviolet Near-Infrared
IR Red Yellow Green Blue UV
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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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VideometerLab 3 Schematic Overview
• Narrowband illumination provided by 19 LEDs between 375-970nm
• Integrating sphere diffuses light onto sample
• 5Mp CCD camera captures reflectance data at each LED wavelength
• Optional emission filter wheel for fluorescence macro-imaging
• Optional bright-field or dark-field lighting for translucency or diffuse scattering imaging
CCD Camera
LEDs
Integrating sphere
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VideometerLab 3 Schematic Overview
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Sizing ring sRGB Watch sRGB
Perceptual Simulation • Here are standard-RGB (sRGB) images of a machine sizing ring and watch
strap as they appear in a normal photograph
• sRGB is the standard computer displays and printers use to render images
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Perceptual Simulation • Human visual perception is well characterised
and understood
• Each sRGB pixel tri-value is calculated using the known %age reflectance values at wavelength bands within the visual range to render the image
• With 19 narrow-band reflectance values for each pixel, we have more detailed data than just 3 broad RGB values
• We can calculate the appearance of an object under any lighting condition
• Noon daylight
• Fluorescent light
• Tungsten bulbs
• We can also view the ‘appearance’ at just one wavelength in greyscale, where black = 0% reflectance, white = max reflectance
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NIR 940nm Violet 405nm
Cyan 505nm
Yellow 570nm
Deep Red 780nm
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NIR 940nm
Data Mining Images
• We can quickly gather more data on Regions of Interest (ROIs)
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NIR 940nm
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NIR 940nm
False-colour Image Enhancement
Each pixel’s grey-scale value represents %age reflectance black = 0% reflectance white = max (22.17% reflectance)
We can enhance contrast to our eyes using the ‘Jet’ false-colour scheme Blue = 0% reflectance Red = max (22.17% reflectance)
Jet NIR 940nm
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Jet MNF Band 3
Image Data Statistical Transformation
Jet PCA Band 3
• Statistical data manipulation algorithms transform image data-cube to highlight spatial-spectral trends
• Mathematics born from satellite imaging and remote sensing field
• 19 Wavelength bands 19 Transformation bands
Minimum Noise Fraction (MNF) Principal Components Analysis (PCA)
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MNF Band 3 PCA Band 3
MNF Band 4 PCA Band 4
MNF Band 5 PCA Band 5
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Trained Image Data Transformation • Guided statistical transformations allow us to compare ROIs directly by
training the transformation algorithm on known data sets • Paint two known conditions to highlight training sets • All other pixels scored on their similarity to training set pixels • Pixel’s entire spectral identity incorporated into weighting parameters • nCDA – normalised Canonical Discrimination Analysis
Jet NIR 940nm
Paint ROIs
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Trained Image Data Transformation
Jet NIR 940nm Jet nCDA transform
Blue = 0% 940nm reflectance Red = max 22.17% 940nm reflectance
Blue = pixels most like ROI 1 Red = pixels most like ROI 2
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Trained Image Data Transformation • Guided nCDA transformations allow us to compare ROIs in
separate images • Sample comparisons • Time lapse studies • Quantifiable, objective and reproducible data for rapid
analysis in research projects
Jet NIR 940nm Jet NIR 940nm
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Jet nCDA transform Jet nCDA transform
Trained Image Data Transformation
Blue = most like watch strap pixels Red = most like sizing ring ROI 2 pixels
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Trained Image Data Transformation
• The trained discrimination algorithm has highlighted an area of blue-scoring pixels on the sizing ring (circled)
• This tells us something about a common chemical identity between the watch strap material and a defined region of the sizing ring surface
Multispectral Image Data Analysis • A variety of image processing
tools and multivariate statistical transforms are available in VideometerLab’s analysis software
• Analysis routines and models can be saved and applied to new samples
• Multiple routines can be run on the same image data to quantify separate parameters
• Routines can be batch-run to aid in high-throughput data acquisition
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• Hardware options
• Emission Filter wheel (4 x 25mm Ø) for fluorescence macro-imaging
• Dark- or Bright-field backlighting for scattering or translucency analysis
• Vibratory feeder for automatic presentation of granular samples
• Software options
• Image Processing Toolbox for filtering and segmentation of image data in individual spectral bands
• Multispectral Imaging Toolbox for multi-variate image analysis and modelling
• Blob Toolbox for object separation, analysis and data output reporting
Hardware and Software Options
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• Hardware warranty and Software support for one year included with purchase
• Software Support Hotline service for simple protocol development helps guide you through image analysis steps (more complicated protocol development is available as a paid service)
• Software updates released on a regular basis (daily build available)
• On site repair response in 3 days
Post Sales Support
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• Nuanced, human-like analysis of heterogeneous samples
• Sophisticated data analysis tools for the novice and power user
• Objective, repeatable data collection with easy export
• Rapid, non-destructive testing with no sample preparation
VL3 Multispectral Imaging
Multispectral imaging at Analytik.co.uk
VL3 Datasheet PDF
