A frequently used technique for obtaining these data is ‘Machine Vision’. A Machine Vision set-up consists of one or more cameras and one or more lamps. The cameras are used to create images (photos). By editing the obtained images, measurements and checks can be carried out. The strength lies in the image analysis software and the lighting used. The software determines what happens to the image. For example, it determines whether a product has been produced as desired by comparing this image with an example. The lighting is important because the object to be inspected must always stand out clearly, without being influenced by ambient lighting. Think of sunlight that illuminates the object at a certain point in time.
Vision technique is very powerful, because instead of a local measurement, such as a laser sensor or physical probe, you can take several measurements at the same time with a single photo. In addition, Vision technique is also used for reading barcodes (Tracking and Tracing). A disadvantage of a Vision solution is that it requires a lot of specific knowledge and the solution is often more expensive than separate sensor technology.
There are two groups of cameras: smart cameras (smart cams) and industrial cameras. As the name indicates, the difference lies in the intelligence of the software. The smart cams have a processor and memory on board on which the image processing software is located. The software is programmed externally (on a PC) and downloaded to the camera. Because the software is located on the camera, you no longer need an external PC. Often a smart cam has digital outputs available for example for a good/fault signal and a bus output for transmitting the measurement results. A disadvantage of this system is that the purchase price of a smart cam is often high.
An industrial camera is the version without on-board image processing software. The camera does not process the images itself, but passes them on. An external PC must then process the images. Because the software runs on a PC, it is often independent of the brand of the camera. The vision library present in the software is often more extensive than that present on a smart cam. It is also possible to connect multiple cameras to the PC. The disadvantage of this system is that a separate PC is needed. An advantage is that the average industrial camera is cheaper than a smart cam.