What are the differences between measurement results obtained by image analysis and laser diffraction particle size analysis?
The measurement result obtained by the laser diffraction particle size analysis is based on the scattered signals of particles captured onto detector arrays. An inverse algorithm is carried out to calculate a theoretical signal intensity distribution, which is compared to the measured one. An index called residual is used to describe the difference between the theoretical and measured signal intensity distributions. The theoretical signal intensity distribution with the smallest residual value is considered the measurement result. In contrast, the measurement result obtained by image analysis is calculated based on the captured images of real particle projections instead of algorithms.
The laser diffraction particle size analysis yields signal-equivalent diameters, which is suitable for the analysis of small micro-level particles, while image analysis provides area-equivalent diameters, measurement of oversized particles is therefore possible.