Key considerations when selecting lens for machine vision system

All of the machine vision systems have a common goal, that is to capture and analysis of optical data, so that you can check the size and characteristics and make corresponding decision. Although the machine vision systems induce tremendous accuracy and improve productivity considerably. But they rely heavily on the image quality that they are fed. This is because these systems do not analyze the subject itself, but rather the images it captures. In the whole machine vision system, the machine vision lens is an important imaging component. So select the right lenses is of crucial importance.

One most important factor we should consider is the sensor of camera when choosing the lens used in a machine vision application. The correct lens should support sensor size and pixel size of camera. Right lenses produce images that perfectly match the object captured, including all details and brightness variations.

FOV is another important factor we should consider. In order to know what FOV is best for you, it’s best to think about the object you want to capture firstly. Normally speaking, the bigger the object you are capturing, the larger the field of view you will need.
If this is an inspection application, consideration will have to be given to whether you are looking at the entire object or just the part you are inspecting. Using below formula we can work out the Primary Magnification (PMAG) of the system.

The distance between the subject and the front end of the lens is referred to as the working distance. It can be highly important to get right in many machine vision applications, especially when a vision system is to be installed in harsh conditions or limited space. For example, in harsh conditions such as extreme temperatures, dust and dirt, a lens with long working distance will be better for protecting the system. This of course means that you need to consider the field of view with respect to magnification to outline the object as clearly as possible.
For further information and expert assistance in selecting the lens for your machine vision application please contact lily-li@jylens.com.