Lenses & optics for imaging and machine vision
Together with the illumination system, the optic forms the first link in the imaging chain of a vision system. Selecting a suitable lens is crucial for the quality of the final image and has an impact on factors such as speed that can be achieved, measuring accuracy, error-free operation, reproducibility and reliability of the downstream analysis. You have questions about optics? Get answers to your questions with the help of our experts at STEMMER IMAGING.
How to choose the right lenses and optics for your application
Selecting the correct lens has a direct relationship to the sensor used in the camera. Parameters such as sensor size and pixel size are of major importance:
- Sensor size ↔ image circle diameter
The lens has to be able to illuminate the complete sensor area in order to avoid shading and vignetting. - Pixel size ↔ optical resolution
The lens has to be able to resolve the pixel size. The better the optical resolution of a lens, the better detailed structures can be reproduced. The optical quality of a lens is defined by the MTF (modulation transfer function) relating to resolution along with the optical distortion. - Object resolution ↔ magnification
In order to resolve the details of an object and to ensure definite edge detection, the detail should be reproduced across about 4 pixels. Thus the required magnification is dependent on the required object resolution and the respective pixel size.
Only the knowledge of all these application specific parameters permits the correct selection of the optimum lens to meet the required field of view and image quality.