Whether it’s for identification, traceability, regulatory compliance, user information or branding, many of today’s products must display markings such as text, logos, symbols and numbers. These markings are typically applied to the surface of product components during the manufacturing and assembly process, and product makers must ensure that they are free of defects, meet quality and brand standards, and comply with trade regulations. Quality and color issues must be identified so they can be quickly addressed and corrected before products go to market.
One of the biggest challenges in this process comes from the limitations of the various technologies used for inspection. Typical machine-vision inspection systems can assess text completeness and accuracy, but they cannot measure accurate color or fine-grain detail. Spectrometers provide highly accurate color measurement, but only for one spot at a time; they also cannot recognize or assess characters or symbols. As a result, manufacturers may have to use two or more different inspection systems, increasing cost and production time.
“Manufacturers typically use multiple methods to inspect markings,” said Hubert Kostal of Radiant Vision Systems. “Device makers may use machine-vision cameras for text inspection and area measurement. Plus, some combination of spectrometers and human inspectors for color measurements. This creates a lot of inefficiency.”
Radiant’s solution is its new Area Color Inspection System (ACIS), which enables users to quickly measure markings such as pattern, text, symbols and color with near-spectrometer accuracy at production speeds. ACIS combines the best of machine vision and spectrometers in a single tool.
The system integrates Radiant’s ProMetric I-series Imaging Colorimeter and lens mounted to a proprietary LED-based dome illumination configuration within a metal assembly frame. The unit can be used in a lab or on a production line to capture accurate images of DUTs. Completing the solution is ACIS software, which combines high-resolution imaging colorimetry capabilities with sophisticated image analysis for accurate quality and color measurement.
ACIS helps manufacturers to ensure characters are legible and correctly formed, verify compliance with requirements for CE and other regulatory markings, ensure brand color and quality standards, perform product text validation, and support part traceability (for example, by confirming serial numbers). The data ACIS captures as it detects small variations in markings can also be analyzed to identify trends and support process control.
“Radiant’s high-resolution imaging colorimetry is a huge advantage,” said Kostal. “Leveraging the visual acuity and context of imaging colorimetry, ACIS provides inspection of text and symbol formation, size, and positioning, while simultaneously taking quantitative color measurements (e.g., CIE L*a*b*) with accuracy and repeatability.”