The Importance of Machine Vision Illumination
Over the years, machine vision cameras have come a long way. Initially, engineers aimed to create cameras that matched the capabilities of the human eye and operated under similar conditions. However, as machine vision applications grew, so did the demand for cameras. In some aspects, cameras have surpassed the abilities of the human eye. Yet, to achieve this, manufacturers need to provide appropriate lighting for machine vision.
Finding Suitable Lighting for Machine Vision
To achieve the required precision and speed, machine vision cameras need proper illumination. This entails not only correct lighting and temperature but also stable and consistent illumination. Depending on the application, various types of lighting can be employed. The primary objective is to ensure proper brightness contrast in every capture.
- Direct front lighting: This type of lighting can partially illuminate surfaces but may cause overexposure. Total reflection causes many surfaces to darken only partially.
- Diffused overhead lighting: This lighting evenly illuminates the surface. It does not provide much contrast, but it is useful when analyzing light and shadow components.
- Dark-field illumination: This type brightens the side edges and often highlights scratches, dust particles, and other defects on the surface.
- Backlighting: Backlighting only provides the outline for machine vision inspection. It cannot collect any surface information, but it is highly suitable for measurement applications.
Why is proper lighting important
Many factors can have a negative impact on lighting solutions. The lifespan of the lamp, temperature, position, and stability of the power supply are some direct factors that may affect the performance of machine vision cameras. Some issues that are not caused by light include changes in ambient light and synchronization between lighting and cameras.
In order to provide reliable and reproducible results, the camera, lighting, and processing systems must work together with the highest efficiency. Depending on the application scenario, it may be necessary to place the lamp at a distance from the component to avoid interfering with the process. Improving this lighting does not always mean increasing intensity. Sometimes wider light than brighter light is needed. At other times, a more focused beam of light is needed.
Build the best lighting solution for your visual applications
Most suppliers provide a wealth of advice on proper lighting for your process. Please remember that lighting choices are usually very suitable for your application and environment. In addition to the factors already discussed, you will also choose between halogen, xenon, and LED technologies, each with its own advantages and disadvantages.
