eyetech - ankersmid technologies.pdf · a time interval, not an intensity measurement. ... from the...
TRANSCRIPT
ANKERSMID
A new technology for measuring particle size
in combination with particle shape and concentration.
COMBINED LASERTECHNOLOGY & DIA
- New laser technique for measuring particle size
and concentration
- Dynamic Image Analysis for particle characterisation
Content
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Why Particle Size Analysis?
Particle size controls many important product characteristics, such as:– Viscosity– Flow-ability– Sedimentation– Optical Properties– Impact/Compressive strength– Agglomeration
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What is the size of a particle?
Size Related Properties :V = VolumeW = WeightS = Surface AreaA = Projected AreaR = Sedimentation Rate
Conventional techniques derive particle size from a (physical) property.
Usually Particle Size is expressed as the diameter of a sphere with similar property -> equivalent sphere
D min
D max
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Equivalent Sphere
These diameters are fundamentally different for the same particle.The equivalent diameters differ for any non-spherical material.Thus, every PSA technique yields different results for non-spherical materials
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Conventional PSA Techniques
The measurement of particle properties has several drawbacks:
- Sphere is an extreme particle shape, not reflecting real particles- Significant errors for non-spherical particles- Particle size results dependent on used technique- Some Instrument response requires calibration depending on the technology used
- Particle size analysis limited to the measured property
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A Modular Particles Analyzer for measuring
� Size
� Shape
� Concentration
in all phases
EyeTech
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The EyeTech performs high resolution particle size &
shape analysis and calculates concentration.
The EyeTech combines two methods of analysis:
Laser channel: particle size measurement & concentration
Video channel: shape characterization by acquiring
images of moving particles and analyzing them with
Image Analysis software
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EyeTech Measurement PrincipleSingle Instrument – Dual Measurement Channels
Range lens A: 0.1-300 µm
Range lens B: 10-3600 µm
LASER CHANNEL
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EyeTech Measurement Principle
The rotating laser beam scans single particles within its focus.
The diameter of the particle is directly correlated to the duration of the obscuration.
The principle measurement is a time interval, not an intensity measurement.
The time domain is independent of particles’optical or physical properties
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EyeTech Measurement Principle
From the duration of the obscuration (t) and the knownrotation velocity of the laser beam (v) the particle diameter(D) can be calculated:
D = v . t
In relation to the high speed of the rotating laser, the particles are stationary. So, particle movement does noteffect particle size measurement.
No requirement for pre-knowledge of:- Refractive index - Temperature- Viscosity variation - Electrical conductivity
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EyeTech Pulse Analysis;Off-Center rejections
Pulse Profile
Off-Center
Pulse Transition
Derivative Profile
Pulse Transition
On-Center
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EyeTech Pulse Analysis; Derivative Pulse Signal
Minimum width and maximum amplitude indicate on-center interactions.
Amplitude
For accepted particlecrossings, the anglebetween the particleboundaries and the laser beam approaches90°.
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EyeTech Pulse Analysis; Out-of-Focus rejections
Pulse Profile
Derivative Pulse
Focused Laser Beam
Derivative Pulses too wide;
Out-Of-Focus pulses are
rejected
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EyeTech Pulse Analysis Concept; Transparent Particles
Opaque Particles Translucent Particles Transparent Particles
Pulse Profile
Particle Size Measurement is independent of particle’s transparency
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Concentration Measurement
Only legal pulses are collected in an optical volume
(defined by the thickness of the laserspot, the focus
depth of the lens and radius of circular movement of
the laser) giving the possibility to calculate
CONCENTRATION
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-No pre-knowledge of sample necessary Refractive/Absorption Index, etc.
- Single Particle SizingDetection of minor fractions
-Applicable to a large variety of samplestransparent, translucent, opaque, airborne, liquidborne
-Possibility of time dependent measurements Crystal growth, dissolution properties
-Concentration measurementsize and concentration at same time � kinetic analysis
Application Advantages
Direct laser measurement
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EyeTech Measurement Principle
Single Instrument – Dual Measurement Channels
DYNAMIC IMAGE ANALYSIS CHANNEL
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Reasons for DynamicImage Analysis
• Seeing is believing, See your particles.
• Better characterization of your materials.
• Detection and quantification of shape influences.
• Validation technique for the laser Channel or other particle size equipment.
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EyeTech Video Channel
• Video Channel collects digital images used for:– Visualization during laser measurement– Dynamic Shape Analysis– Grabbing Images and Recording Movie
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Dynamic Image Analysisthe way it is done
� Real time images of particles in motion are collected
420 µm
18 µm
Image Conversion
� Images are converted into a grid containing a collection of picture elements (pixels). Each individual pixel has a value for brightness (grey level):
0 = Dark; 255 = White.
� All images are analyzed according to a pre-defined set of Image Analysis characteristics.
� Measurement is finished when the measurement end condition is met (#of particles/images, confidence level,time)
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Dynamic Image Analysis
• For each individual particle, size and shape parameters are determined.
• The EyeTech Image Analysis software automates set-up and measurement.
• EyeTech software includes many IA procedures such as:– Pre-processing procedures– Image Filters– Region of Interest– Out-of-focus Rejection– Morphology Operations– Grouping according to size/shape– (Re-)processing of stored images and movies
– Lens Calibration
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Dynamic Image Analysis
• Pre-ProcessingImage quality can be improved using automatic pre-processing procedures, e.g.: Contrast Enhancement:
Contrast Enhancement increases the number of gray levels
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Image Analysis TermsBasic Image Analysis terms:
Macro Size Descriptors
Ferret Diameters
Determination of distributions of:- Minimum Ferret- Maximum Ferret- Average Ferret
Average Ferret diameter:
F1 + F2 + F3 + F4 … F36 36
For a sphere size = diameter
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Image Analysis TermsBasic Image Analysis terms:
Macro Size Descriptors
�Perimeter
�Equivalent Diameter
This parameter gives the diameter of a circle of
equal area to the object.
�Specific Length
This parameter gives the average length along a
sinus-like object (fiber) and is given by the
formula:
π
AreaDiameterEquivalent *2=
)Area*16-Perimeter² (Perimeter*¼ +=ngthSpecificLe
Spe c ific Le ng th S pe c ific Le n g th
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Shape Analysis TermsBasic Image Analysis terms:
Macro Shape Descriptors
[ min Ferret diam.]
Aspect Ratio = --------------------------
[ max Ferret diam.]
[Area * 4 π]Shape Factor = ------------------(Circularity) [Perimeter]2
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DSA ParametersComparing Shape Factor to Aspect Ratio
Shape Factor Aspect Ratio
1 1
<0,1 1
0,785 0,707
0,604 0,577
0,436 0,250
0,160 0,100
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Image Analysis TermsShape Descriptors
Additional Parameters:• Over 40• User defined• ÌSO-parameters• Elongation• Curl-index• Modification Ratio• Compactness• Roughness• Wadell’s Sphericity• Solidity• Convexity• Average Concavity• Fractal Dimensions
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• No difference in particle size distributions fordifferent materials
• With Dynamic Image Analysis, the differenceis evident
Quantifying equivalent diameters
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Quantifying shape differences
• The difference in the shape factor and maximum Ferret diameter are obvious!
Max. Ferret Diameter:
Shape Factor:
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Application Advantages
Particle classification using strategic shape filters Selection of particles of interest by their shape in a large matrix
Dynamic Shape Analysis
Accurate determination of agglomeratesSpecific shape of agglomerates are used to select them
Visualization and characterization of foreign particlesSelection of foreign particles by their shape
More accurate characterisation of non-sphericalRods, fibers, Aggregation, Foreign Particles