HAL-series ring light units combine bright, indirectly incident diffuse light with compact dimensions. The ring light units are equipped with one light source, producing very even, homogeneous light emissions intended for additive colour mixing (RGB type). Use ring light units to produce diffuse dark field lighting with the optionally available shading sleeve. 24V PWM signals control the ring light units and there is no need to use PWM signals to transfer power.
Our ring light units are mainly used to illuminate objects with highly reflective surfaces where shading and reflections must be avoided.
The STV highlight: one RGB type with RGB LEDs and additive colour mixing – ideal for image processing! Create almost any lighting colour using just a single ring light unit. Create an enhanced white compared with conventional, white LEDs!
Image processing with black and white cameras
When selecting suitable lighting, the wavelength spectrum is very important. In a real black-and-white image different colors may have the same brightness values, so that there is no longer sufficient contrast difference and further processing becomes difficult or even impossible. Here it is worthwhile to try different colors of light in order to achieve a sufficient contrast. These are our RGB ring lights best suited. They simplify the commissioning of an image processing system on site or even make it possible for the customer to do so. It is no problem to change the color if the surrounding has changed. Thanks to our PWM modules with Web interface and Modbus-TCP, an RGB ring light can be operated completely independently or, alternatively, controlled by any image processing software.
Image processing with color cameras
White light is ideally composed of a multitude of spectral colors. Depending on the nature of the illuminated object, light of different wavelengths is absorbed, reflected or transmitted differently. For example, if a body illuminated with white light shows a high absorption for yellow light, in the remaining reflected light this proportion is lower than before. In this case this body appears blue (complementary color to yellow). If an object is illuminated with its “own color”, it will appear bright in the picture, if it is illuminated with the complementary color, it will appear dark.
In color image processing, it is expedient to work with white light. For this purpose, a suitable light source is of crucial importance. Although white LEDs appear to be halfway white to the observer’s eye, they actually have a limited spectral range of sufficient intensity. For a white LED, the luminescence wavelength conversion is used. RGB ring lights are also better in the color image processing.
