From Particle Formation...
... To Particle Characterisation

Particle Shape

Particle Shape Analysis

Our range of Occhio instruments provide particle shape analysis starting from 200 nanometers and ranging up to centimetres for laboratory, at-line and on-line solutions.

A particle’s shape, as well as its size, can significantly affect the physical characteristics and process handling of many particulate materials, as well the properties of the product itself, especially for active pharmaceuticals. Studying and understanding the morphology of particles can lead to increases in manufacturing efficiency as well as improvements in product performance.

Image analysis can inspect many thousands of particles to ensure that the results are statistically significant for the sample, even for fibres and touching particles – the type of materials that other methods can find difficult to fully analyse.  

Shape analysis is performed by dispersing the particles and viewing them with a high quality light source, optics and camera. Software then analyses the images to determine various properties.

Size and Morphometric Measurements


Inner Diameter - (also known as Sieve Diameter) maximum inscribed disc within a particle, computed with a true Euclidean Distance Transform. The fast and accurate algorithm developed is exclusive to Occhio, providing for computing real size distributions.
Area Diameter - diameter of the equivalent area circle.
Mean Diameter - mean of all radii joining the centre of mass and the outline's pixels (also mean particle diameter).
Area and Volume - computed on the particle projected area.


Inertia Elongation - computed from one minus the ratio between inertial ellipse axes.
Feret Bounding Box - bounding box parallel to the Inertia Ellipsoid.
Width and Length - computed directly on this Feret Bounding Box.
Max Distance - maximum distance found within the particle.
Convexity - defined as one minus the ratio between convex area and particle area. The convex area is built with a virtual rubber band fitted on each particle.
Reactivity - (also known as Circularity) defined as the ratio between the equivalent area circle perimeter divided by the actual particle perimeter.
Shape factor - computed with the formula SF=P2/A where P is the Perimeter and A the Area.


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particle shape

particle shape analysis

particle shape factor

Find out more about our range of particle shape analyzers: