Start typing and press Enter to search

This website does not support Internet Explorer. For a correct visualization we recommend to use Microsoft Edge or Google Chrome.


Sensofar Focus Variation

The Focus Variation optical technology has been developed for measuring the shape of large, rough surfaces. It is based on Sensofar’s extensive expertise in the field of combined Confocal and Interferometric 3D measurements, and is specifically designed to complement Confocal measurements at low magnification.


Focus Variation principle

The Focus Variation technology takes advantage of the limited depth of focus in brightfield images, where only a certain z-range of the sample is in focus. This value changes depending on the numerical aperture of the objective or the light source wavelength. The Z value is calculated measuring the high frequency components (sharpness or tiny details) of the image, resulting in the optimal focus position.

Background AiFV


The optical scheme based on our patented microdisplay technology shows the light passing through different optical elements from the light source (LEDs) up to the camera. In that case, the microdisplay works like a mirror (100% reflectivity). This optical scheme is like a standard video microscope. Bright field images can be captured in every plane by performing a vertical scan.

S neox Ai Focus Variation Configuration


Overcoming the limits of Focus Variation

On non-textured surfaces, the focus operator does not provide enough signal to recognize the best focus position. This is typically the case on optically smooth surfaces, providing noisy 3D results. Sensofar systems have been improved with the use of active illumination to get more reliable focus location even on optically smooth surfaces where the focus operator does not provide enough signal, because of poor contrast. Now, the microdisplay projects an artificial texture (chess board pattern).
Read our paper about Active Illumination Focus Variation

Ai Focus Variation Algorithm
Banner Webinar AiFV
Insert AiFV


Highlights of the technology include high slope surfaces (up to 86°), high speed (up to 3mm/s) and large vertical range measurements.

  Measures slopes up to 86º on scattering surfaces 

  Active illumination allows measurement on smooth surfaces 

  Fast acquisition, 200 planes in 3 seconds 

  Multiple light sources


Ai Focus Variation systems


Get answers to your questions!
Connect with an expert

Just write us an email or search for
a direct contact near you.


Get answers to your questions!
Connect with an expert

Just write us an email or search for
a direct contact near you.