Lighting, as anyone who designs industrial process vision systems knows, is a key parameter to obtain useful images from the cameras. Taking for example the need to photograph a small object with a camera. The technical features must inevitably be connected to a LED illuminator able to give a homogeneous light, but above all suitable for the type of photo to be taken. That is because depending on the object, i.e. the type of surface, different kinds of lighting can be provided. A reflective surface needs a homogeneous light to minimise (or rather, cancel) the reflection, which prevents the camera from capturing the image correctly. A surface of a certain colour, on the other hand, needs to be illuminated by a light of a complementary colour. (for example, a red surface, illuminated by a red light). Among the various types of led illuminators, the RING LIGHTS are generally used in all those machine vision applications where it is necessary to directly illuminate the object to be controlled.
The GEST series includes three different types of RING LIGHTS.
The design assumptions sought to make the product:
Cheap and functional;
Adaptable to the vision system requirements.
Moreover, the application areas are:
- Computer Vision; - Machine Vision;
- Quality control with vision systems.
One series, three products
1) GEST 42-74-120
Among the RING LIGHTS of the GEST series, the GEST42, the GEST74 and the GEST120 were the first to be designed. The need that started the development was to have an efficient yet economical illuminator with simple construction. At just 10 mm thickness, this series manages to offer a solution in those Vision System in which space is limited but a good lighting is still required. There are three available dimensions, designed on the basis of the major market needs. As stated in the product code, they are available with external diameter of 42 mm, 74 mm o 120 mm. The real advantage of this product, however, is the LED board, which, depending on the application purposes can be white light, coloured light or even infrared light and again depending on the camera requirements, continuous or strobe use. There are only two application limits for this series:
The low protection degree (IP20), while keeping the price of the product lower than other illuminators of the same type, does not allow a wide-ranging usability, especially in those systems that use liquids or vapours for cleaning.
The potential reflection of the led light spot in some vision systems, feature that could compromise the image capturing.
2) GEST 44-76-122
The basic project of the RING LIGHTS GEST42-74-120, previously explained, evolves into the series GEST 44-76-122. In order to improve the weaknesses such as the protection degree and the light spot, the mechanical structure has been raised from 10 to 25 mm of thickness, in this way an opaline or transparent cover can be added. The product keeps its compactness, furthermore the advantage obtained thanks to the cover is the remarkable increase of the protection degree, that turns into IP65. Moreover, in the opaline version, the light becomes very uniform and prevents the annoying reflection of the led light spot.
3) GEST 76 – 100
The last news introduced among the RING LIGHTS for the GEST series is represented by the GEST100 and the GEST76. The innovative challenges coming from the last generation of vision systems have required a compact and safe illuminator as far as the protection degree is concerned and the ability of focusing the light.
Thanks to this requirement an illuminator has been designed in order to focus the light at 20°, 40° or 60° through the aid of a secondary lens. In addition, we noticed that it was necessary to make another improvement to ensure a higher protection of the illuminators against the wrong starting caused by the users. For this reason, a microprocessor has been put inside the led electronic boards that work in the strobe modality, it controls the starting time and ensures that the maximum time that the illuminator can work is respected in order to prevent its damage. Less problems mean a higher customer satisfaction. Thanks to these features, the product guarantees high performances in all the applications that require a considerable light quantity and/or those that need to illuminate a very far target.