MEPCA spoke to Richard de Courcy, Product Specialist, KEYENCE UK Vision and Measurement, about the role lighting plays in today’s machine vision systems and why, he believes, it remains critical despite advances in the capability of the systems analysing machine vision imagery.
MEPCA: Keyence’s vision systems have won Innovators Awards every year since 2015, including gold last year – what’s so innovative about your systems?
Richard de Courcy: For us, machine vision is not only about having a toolset capable of meeting the requirements of the application; it is about creating the environment to make the inspection as simple and stable as possible. Our vision systems are controller-based, linking the capture to the illumination, giving us greater capability to create the best inspection conditions.
M: Why is lighting so important in machine vision applications?
Richard: A professional photographer will use a studio so they can control the lighting to get the image they want. Machine vision is no different in this aspect; the key to getting a great image is to find the right lighting. If we can be successful in our lighting for an application, the features we are looking for are enhanced, and our inspection is made easy.
M: So, inadequate lighting can cause issues for vision tasks; what are some of the common examples?
Richard: All machine vision tools work off contrast, we want to illuminate or darken features to the background, so they are more identifiable. Problematic features could be something like foreign contaminants, oil stains or other scuff marks, even distinguishing between parts of similar colour. Defects such as these can be hard to define with inadequate lighting.
M: The properties of the target being scanned can also present lighting challenges; what are these?
Richard: On shiny or glossy surfaces, glare can present a challenge to inspection. Changes in depth can also be difficult to define, especially if the part is all one colour. The same principles apply to engraved parts.
M: How does Keyence’s lighting solutions overcome these challenges?
Richard: Keyence’s advanced lighting range are all designed to address these issues. Using Pattern Projection Lighting, we create high contrast in areas where there is a depth change. Multi-spectrum is used to again find high contrast in areas where the colour change is subtle. Whilst Lumitrax uses the direction of light to remove glare and highlight any hidden surface features.
M: As machine vision software advances, it is becoming better equipped in categorising these challenging defects. Therefore, is creating the best conditions for inspection still a necessity, and if so, why?
Richard: Every customer wants to have the most reliable solution for their inspection, and we want our equipment to provide stable operation at any site. As is common knowledge, a simpler solution is a more robust one.
Having the best image reduces the complexity of programming required for an effective inspection. It also reduces the time required to run the image enhancements and tools to make the solution stable.
When we can present a feature or highlight a defect clearly, it means the tools used to categorise this are easy to set up by nature, and we can have greater control over their tolerances and individual parameters.
The more we rely on the algorithms within the vision system to define good and bad parts, the less control we have over these parameters. This means that an inspection with good lighting will be far easier to troubleshoot and maintain. It is clear the best approach is to avoid challenges through effective lighting.
M: This approach is reflected in your systems which have won several awards for innovation. What does that look like in practice?
Richard: For us, machine vision is not only about having a toolset capable of meeting the requirements of the application; it is about creating the environment to make the inspection as simple and stable as possible. Our vision systems are controller-based, linking the capture to the illumination, giving us greater capability to create the best inspection conditions.
For free demos: www.keyence.co.uk/landing/vision/demo
General link: www.keyence.co.uk/vision/mepca
