Customers of today’s consumer electronics devices expect a flawless product out of the box. Scratched, dented, smudged, and otherwise imperfect products result in costly returns and may damage your brand’s reputation and future business. Quality control activities to prevent and detect surface defects rely largely on human inspectors. Humans can apply their acute visual perception and immediate judgment during production to ensure defective products are not shipped to consumers. However, the faster the production rate, more complex the product, or more obscure the defect, the more difficult it is for humans to keep up with throughput demands while adhering to the need for absolute quality.

Radiant ProMetric® Imaging Photometers are engineered to measure and detect subtle variations in light uniformity across illuminated components. Our solutions combine the speed and consistency of automation with the discernment of human vision. Using advanced photometric measurement capabilities, Radiant imagers are ideally suited for detecting anomalous features on surfaces and grading these defects based on their location, scope, and severity. You will experience all of the benefits of automated cosmetic inspection, including objective analysis and quantifiable results, and get the data you need for error tracking to improve production and operations. An extensive set of machine vision and photometric evaluation tools are also available for production-level monitoring and pass/fail test sequencing using Radiant’s TrueTest Automated Visual Inspection Software.

Scratches, Dings, and Dents

The Advantage of Photometry-Based Imaging

The performance of a machine vision inspection system depends on the quality of images it can acquire. High-quality images enable the system to “see” defects in greater detail and apply meaningful evaluations. The resolution of a standard machine vision camera sensor typically ranges from one to five megapixels. Radiant solutions leverage the superior resolution and dynamic range of our ProMetric Imaging Photometers.

Unmatched Camera Resolution and Dynamic Range

Our Advanced Vision systems capture unmatched image clarity. Their high dynamic range can detect hairline variations on part surfaces caused by reflections of light (like shadows that indicate a scratch), while high resolution image sensors can image and classify defects with extreme precision. Radiant cameras detect defects unnoticed by human inspectors, including light scratches on glass and foreign particles.

A Radiant imaging solution offers superior dynamic range for surface inspection, even when compared to higher-resolution systems. In the examples below, two cameras are used to image a scratched aluminum surface (dark images on left), and contrast differences are analyzed to identify surface scratches (graphs below).

The first image was captured using a Radiant ProMetric Y29 (29-megapixel) imaging system. The corresponding graph shows four large peaks where four scratches are identified. The bottom image was captured using a third-party 71-megapixel CMOS vision system. Even to the human eye, this image exhibits fewer contrast differences. In the corresponding graph, only three large peaks are registered, indicating that the 71MP sensor does not have sufficient dynamic range to identify the first scratch (indicated by the left-most of the four peaks in the Radiant analysis graph).


Comparison of Radiant versus Other Imaging Solutions


Radiant ProMetric® Y29 (29-megapixel imaging system)

Third-party 71-megapixel imaging system

Unknown Defects in Unknown Locations

Radiant offers complete camera systems that use advanced imaging technology and sophisticated algorithms to locate and characterize randomly-occurring cosmetic defects on device surfaces, including unknown defects in unknown or unpredictable locations on a part. By taking a wide area image of a device, our systems can perform uniformity checks to detect hairline scratches, subtle dents, or even fingerprints on device surfaces. The systems can classify the severity of each defect against acceptable tolerances and apply pass/fail values, just as a human would use their judgment to determine a reasonable margin of error.

Unlike human inspectors, however, Radiant solutions can apply numeric values to each defect and quantify these by size, shape, location, frequency, and rate of occurrence, building trend analysis data that allow you to fine-tune processes, improve product quality, and increase production efficiency. Built on the Radiant TrueTest Software platform, these systems can simultaneously perform other inspections, including part orientation, assembly verification, fit and finish analysis, and label legibility, eliminating the need for a separate machine vision system on the line.


Dent detected on tablet back.

A dent’s length and width can be measured to determine whether a device passes or fails.

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