Six machine vision lighting design considerations

Machine vision lighting is an aspect that is sometimes overlooked, but having an understanding of how it will look and what the visual settings and limitations are will be crucial to making the automated imaging system a success.
By AIA September 4, 2017

Image courtesy: Bob Vavra, CFE MediaMachine vision lighting is a critical component of a successful automated imaging system. Without proper lighting, your machine vision system will not function as intended and may provide skewed or inaccurate results. Every machine vision application needs its own lighting solution. Many processes could be illuminated a few different ways and every lighting technique has its pros and cons.

Integrating a machine vision lighting system is a complicated undertaking and there are several application-specific considerations to take into account before implementing anything. The best way to start is to know what lighting design factors to consider for your application. These six machine vision lighting solutions, in particular, are useful for any application.

1. Determine the exact feature of interest

Determine in advance exactly what a proper machine vision and lighting system will produce. For example, in inspection applications, determine what a properly illuminated part will look like, and which areas are most important for inspection, and therefore most important for lighting.

2. Analyze part access and presentation

Will the part be clear or obstructed? Will it be moving or stationary? You need to understand how the part is presented to be able to accommodate for this in lighting design. Part presentation will have a significant impact on the resulting lighting system.

3. Analyze surface characteristics

Texture, reflectivity, contrast and surface shape all have an impact on lighting and must be taken into consideration. A curved surface, for example, will have different lighting requirements than a flat surface.

4. Understand available lighting options

What type of lighting equipment will you use: rings, domes, bars, spots and/or controllers? Will you use bright field, diffuse, dark field or back lighting? Users need to understand all available options to choose the best one for a particular application.

5. Understand lighting limitations

Many applications have inherent limitations for enhancing illumination. Contrast enhancement, for example, could be limited by light direction and wavelength. Take into consideration the pre-existing limitations in your application.

6. Factor environmental issues

Machine vision lighting does not take place in a vacuum—environmental factors will always be an issue. Ambient light, for example, can have a dramatic effect on lighting systems, creating inconsistent lighting environments.

The six considerations above are a broad overview of all the things you need to consider before implementing a machine vision lighting solution. Machine vision lighting is an integral component of any machine vision system, but integration and design can be a challenge because of the number of variables users need to consider.

This article originally appeared on the AIA website. The AIA is a part of the Association for Advancing Automation (A3). A3 is a CFE Media content partner. Edited by Chris Vavra, production editor, Control Engineeringcvavra@cfemedia.com.

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