Particle Inspection

Dust detected below smart device glass.

Particle inspection is a subset of cosmetic surface inspection in which foreign materials appear on or within transparent components like clear plastic, film, or glass. These particles may cause material to be unsuitable for a subsequent process in manufacturing, or dangerous for application or consumption. Automated visual inspection systems in these applications must be specially-calibrated to detect and distinguish between particles and their locations. Understanding whether a particle is on the top or bottom of a surface, or embedded within the surface, allows adjustment of operational processes to determine if an inspected material can move on to the next phase of production, if cleaning is required, or if the material must be rejected as scrap.

Radiant’s automated visual inspection solutions employ extremely high-resolution, high-dynamic-range CCD sensors to image transparent materials under unpredictable lighting conditions. Minute contrast variations within an imaged area allow these cameras to assess the presence and location of particles and apply defined tolerances to determine the acceptable severity of a particle or number of particle within the material.

Unmatched Camera Resolution and Dynamic Range

Leveraging extremely high resolution (up to 29MP) and dynamic range (up to 73.4 dB) CCD sensors, Radiant’s ProMetric® Imaging Photometer or Colorimeter captures unmatched image clarity for detecting the smallest particles on or within any substrate. Dynamic range increases the number of grayscale values captured in each image, ensuring that subtle contrast variations are identifiable for fine-detail inspection. The high resolution of Radiant cameras ensures that pixel-sized particles and image noise are clearly discernable. Image noise is further reduced by interline cooled CCDs in Radiant’s ProMetric cameras, which ensures the clarity of images acquired while maintaining inspection speed. Utilizing these technical advantages, Radiant inspection systems can detect defects that may go unnoticed by human inspectors, including tiny, light-colored debris on glass or metal surfaces.

Radiant automated visual inspection software detects particles on this metallic surface that appear invisible to the human eye.

Particles in Consumer Electronics Components

Product quality expectations in consumer electronics are arguably the highest in any industry. Customers demand perfection in their devices and newly-released technologies are routinely reviewed in excruciating detail. A subtle scratch on a laptop surface, or miniscule dust particles behind the glass of a smartphone camera lens, are sufficient cause for product returns and – if widespread – may lead to recalls, costing manufacturers excessive time and money.
Integrating cosmetic surface inspection and particle inspection into quality control operations during production and at final assembly is imperative for safeguarding the consumer electronics manufacturer’s ROI. From a single camera/software combination, Radiant machine vision solutions employ the complete library of machine vision tools in the TrueTest™ Software platform, performing particle, surface, and assembly inspection routines at once for total quality control.

Dust below a smartphone camera lens is detected using specialized lighting to reduce glare from specular glass and increase particle contrast.


Particles in Pharmaceutical and Cosmetic Fluids

Particles detected in parenteral fluid.

Because they are applied to the human body, fluids used for cosmetic and medical purposes must be free from foreign particles in order to safeguard consumer health and wellness. With so much at risk, industries are well-regulated, requiring manufacturers to perform human inspection of fluids to ensure products are contaminant-free and safe for use. However, undissolved particles and other particulate matter that may be unintentionally present in a solution can be difficult for the human eye alone to detect, especially when specular glass and fluids may cause reflections and obscure the particles from view.
Using photometry-based imaging technology to simulate human visual perception, Radiant photometers and colorimeters are capable of performing visual inspections to the caliber of human inspectors. Beyond this, a Radiant particle inspection system is integrated with the highest-resolution imaging hardware (up to 29MP) and a variety of lighting geometries to enable the system to detect and classify particles behind glass and within fluids, regardless of shape or color, which may go unnoticed by the human eye. In regulated industries where manufacturers are obligated to perform human inspection, an automated visual inspection system can be used to augment human inspectors or verify human inspection to ensure that particles are not missed during the initial review. A Radiant inspection system may also relieve the burden of manual inspection, and ultimately speed up the inspection process, performing instant particle detection as well as surface inspection tests for container cracks, bubbles, or other defects.