The reliability of particle images is tightly linked to the rate at which samples traverse the imaging field

When particles move too quickly, they may pass through the focal plane of the imaging system too rapidly to be captured with sufficient clarity

generating low-resolution artifacts that obscure particle boundaries

On the other hand, insufficient flow allows particles to aggregate or sink under gravitational and hydrostatic forces

resulting in spatial heterogeneity and inaccurate quantification of particle density

Each extreme—too fast or too slow—undermines the integrity of morphological and numerical outputs

The ideal flow velocity depends on key particle characteristics such as diameter, mass density, and geometry

as well as the characteristics of the imaging system itself, such as exposure time, frame rate, and depth of field

For instance, smaller particles require slower flow rates to allow the camera to resolve fine details

whereas bulkier or heavier particles can sustain faster flows without losing image fidelity

Additionally, systems with high frame rates and short exposure times can accommodate faster flows while maintaining image sharpness

entry-level instruments typically demand slower delivery rates to avoid motion artifacts and focus loss

The velocity of sample flow directly modulates the fluid-mediated forces acting between particles

At higher velocities, shear forces can align elongated particles or separate aggregates that might otherwise be detected as single entities

Failure to adjust for fluid-induced particle behavior can result in erroneous detection and classification

In contrast, overly stagnant conditions may promote particle-particle interactions such as aggregation or sedimentation

resulting in undercounting and biased statistical representation of the sample

Calibration and validation procedures are essential to determine the ideal flow rate for each specific application

Scientists routinely test standardized particles with defined dimensions and densities to evaluate flow-dependent imaging performance

These tests help establish the operational window where particle trajectories remain stable, images are in focus, and statistical sampling is representative of the true population

Manufacturer guidelines offer baseline values but rarely account for sample-specific complexities

Field samples rarely match idealized standards, demanding iterative optimization of flow parameters

Real-time feedback from metrics including noise levels, 粒子形状測定 edge sharpness, and trajectory stability supports on-the-fly flow modulation

Flow rate management is a fundamental experimental variable, not just a machine setting, for credible particle analysis

Ignoring flow dynamics can corrupt data irreversibly, no matter how advanced the camera or algorithm

Any lab depending on particle imaging must rigorously standardize and archive flow parameters to ensure reproducibility and accuracy