Adjusting or balancing the intensity of the illumination so that it best meets the requirements of the application is a fundamental of vision lighting control. As the intensity of an LED illumination is directly linked to the electric current, illumination controllers with current control are also suitable for brightness control.
Dynamic intensity control
This technique can be used to dynamically adjust the LED brightness to suit changing ambient illumination levels or brightness changes of the target. If the brightness level of an LED illumination drops over time, alighting controller can be used to automatically compensate, so that the captured images maintain the same brightness and contrast. Another potential application might involve adjusting a lighting set-up when used with identical components, but with different surface finishes. The different surfaces will reflect varying amounts of light which will require the lighting to be altered dynamically.
Multi camera lighting control
There may be situations where multiple cameras are used in a single inspection. For example, a product may go through 3 different checks, with each requiring a different illumination set-up. These will need to be controlled so that the lights are sequenced with each camera exposure. A lighting controller is used to ensure that only the correct light is active at any one time, and that the different illumination arrangements will not adversely interact.
Decision based lighting control
At a more basic level, a single camera inspection set-up can perform a range of different inspections. In this scenario, different lighting set-ups can be toggled on/off, either by an operator or via a programmable lighting controller. Such a system can react to different objects or components and use different lighting, depending on what features need to be imaged. This approach can reduce costs by allowing a single inspection system to analyse a range of different objects with different illuminations dependent on the product being inspected.