Illumination

All design of optical measurement systems involves illumination design. The optimal illumination depends on the measurement task. Characteristics in the object can be enhanced or suppressed with lighting, in order to simplify the measurement and analysis task. This applies as much to spectroscopy as to machine vision.

All illumination design starts with a rigid analysis of the measurement task. Which physical parameters are measured: colours, texture, geometry, concentration, temperature, material type, thickness, speed, scattering? Which spectral region or wavelength of the lighting is best suited? Should the light be transmitted through the object or reflect on its surface? Should the light be diffuse or collimated? Or modulated? What is worst case and how do we handle it? Are there constraints and requirements such as geometry, price, overall size, interfering light sources, harsh environments, hygiene, lifetime, power consumption, eye safety, design and so on? What detection method is used? Preliminary illumination solutions are tested and refined with the rest of the measurement system.

Application examples:

• Light Emitting Diodes (LED) design for cheep, long lasting and low effect consumption lighting systems
• Structured light for 3-D measurements
• Lasers are used in 3-D scanning systems
• Colour measurements
• Lighting for optimal imgaging quality in machine vision systems