From Image to Measurement: How Optics, Illumination and Edge Detection Determine Measurement Accuracy

Optical measurement systems can provide fast, repeatable dimensional measurements, but reliable results depend on much more than the stated accuracy of the measuring system. The quality of the image presented with the measurement software plays a fundamental role in determining where a feature begins, ends, and ultimately how it is measured.

This presentation examines the relationship between optics, illumination, image quality, edge detection and dimensional measurement. Using practical manufacturing examples, it will demonstrate how reflective surfaces, low-contrast features, complex geometries, burrs and inappropriate illumination can affect the apparent position of an edge and influence measurement repeatability.

The session will explore strategies for optimizing illumination and contrast, selecting appropriate magnification and optical configurations, and reducing operator-dependent variation. Attendees will gain a practical understanding of how the entire optical imaging chain—from the component and illumination through the optics, camera and image-processing software—contributes to a reliable measurement result.

Attendees will learn how to:

• Understand the relationship between optical image quality and dimensional measurement results.
• Recognize how illumination, contrast, magnification and surface characteristics can affect edge detection.
• Apply practical techniques to improve measurement repeatability and reduce operator-to-operator variation.

About the presenter
Colin Robinson is a senior metrology manager at Vision Engineering, Inc., based in the Kennesaw, Georgia area. With more than forty years of experience in precision metrology, he has held technical, applications, sales, and management roles supporting coordinate measuring machines, video measuring systems, and related non-contact inspection technologies.

In his current capacity, he provides technical support, customer training, product demonstrations, calibration and service-related activities, and field assistance for Vision Engineering’s metrology systems. His work includes support for video measuring machines and related software platforms, along with process automation and documentation.

Robinson completed studies at the University of Nottingham from 1981 to 1985, earning the United States equivalent of a Bachelor of Science degree in computer aided engineering, with a focus on metrology and computer sciences.