The Active Illumination Focus Variation (AiFV) is an optical surface measurement technique that reconstructs surface topography by vertically scanning the sample and acquiring images at different focus positions. The surface height is determined by analyzing the local sharpness of surface features, where the position of maximum focus corresponds to the surface height.
AiFV introduces a controlled synthetic illumination pattern within the optical path. This pattern modulates the reflected signal and enhances local contrast, particularly on smooth, low-texture, or highly reflective surfaces.
HOW DOES AiFV WORK?
The measuring principle of Focus Variation is based on:
Principle of Focus Variation: Image sharpness depends on the focal distance. The sample appears blurred when above or below the focal plane, and sharp only at the correct z-position.
Axial scanning: The system acquires a stack of images at different focal depths as it scans through the z-axis.
Focus evaluation: A focus operator measures the local contrast around each pixel; maximum contrast indicates the best focus position and is used to calculate height.
3D reconstruction: Focal regions from all images are combined to build a detailed 3D topographic model of the surface.
Artificial texture projection: AiFV introduces a controlled pattern onto the surface, ensuring sufficient contrast even on smooth or reflective samples.
Enhanced measurement capability: By adding this artificial texture, AiFV extends focus variation to surfaces with insufficient natural texture, enabling accurate and reliable 3D measurements.
APPLICATIONS
Ai Focus Variation is applied in fields such as precision manufacturing to inspect finely machined parts; in the medical and dental industries to analyze implants and prosthetics with irregular shapes; and in electronics manufacturing.
