At its core, a machine vision system has one task and that is to “collect and process optical information so measurements, observations or decisions can be made.” All of this happens without human intervention, other than at the beginning of the process when the specifications are input. The benefit of a machine vision system is that it takes humans out of the equation and typically makes the process move more swiftly and smoothly.
Because a machine vision device lacks the ability to make decisions on whether the information being input and the items being put out, it won’t perform at high quality if the individual inputting the information is putting in poor or incomplete specifications. One of the major components to make the final product of stellar quality is to have the correct optics and machine vision lenses to perform the task.
Machine Vision
When a manufacturer is evaluating the requirements of a machine vision system he will have to settle on a lens class for it. There are three options in lenses and they are:
- Endocentric – this produces images with the same perspective as the human eye
- Hypercentric – this lens inverts the perspective and allows for a view of the entire surface of a 3D item
- Telecentric – helps to eliminate perspective errors
A machine vision system on a factory floor has a specific task to perform. The task, which includes all of the moving parts from information input to final product development needs to be carefully planned because the final product is only as good as the information specifications input.
Processes that involve precise measurements or to read bar codes are typically suited to endocentric lenses. If you’re manufacturing a product that, for example, has to verify both internal and external diameters of a product and keep perspective regardless of where these products are on a conveyor belt, a telecentric lens is best suited to that because its magnification doesn’t vary regardless of the distance of the object.
If you have an object that has exterior markings that need to be precise – such as on a syringe – you would want to utilize a hypercentric lens because that allows for a view of the entire line of markings in one view rather than multiple ones.
Spending the money on telecentric or hypercentric lenses will likely pay for themselves in the long run because of their efficiency and effectiveness in making the machine vision process run smoothly