Selecting and configuring the optimal lighting set-up is one of the most crucial factors in the design of a vision system. The missing information which is caused by a wrong exposure makes further analysis much more difficult or even impossible, because missing information in the image can never be found by the analysis algorithm. The kind of light is often determined by things like: colour, texture, size, shape, reflectivity, etc.
OPTICS AND CAMERAS
Cameras have lenses that gather the light that is scattered from the surface of an object. The lens recreates this scattered light as an image on a light sensitive area behind the lens, normally a CCD or CMOS sensor. When selecting a camera for an application three factors have to be considered: the performance of the sensor, the camera, the interface technology and the image transfer.
ACQUISITION AND TRANSFER
Acquisition technology has seen major changes in the past years, in particular the introduction of new bus technologies. Traditional frame grabber technology is connected by a set of generic interfaces, such as FireWire and USB (2.0 and 3.0), along with Gigabit Ethernet.
The basis of all graphic software is the ability to acquire, transfer, manipulate and interpret the pixel data that is displayed by a camera. What happens to these images can vary from the relatively simple task to store them on a disk, to its use in a complex application with pattern recognition.
When selecting a computer for imaging application, there are many factors that should be considered to ensure that the chosen solution delivers the required performance and guarantee a long reliability; and stability of the system.
A vision system uses analogue and digital electronics, grounding techniques and requires EMC and ESD-knowledge.