A novel Vision ray metrology technique is reported that estimates the geometric wavefront of a measurement sample using the sample-induced deflection in the vision rays. Vision ray techniques are known in the vision community to provide image formation models even when conventional camera calibration techniques fail. This work extends the use of vision rays to the area of optical metrology. In contrast to phase measuring deflectometry, this work relies on differential measurements, and hence, the absolute position and orientation between target and camera do not need to be known. This optical configuration significantly reduces the complexity of the reconstruction algorithms. The proposed vision ray metrology system does not require mathematical optimization algorithms for calibration and reconstruction – the vision rays are obtained using a simple 3D fitting of a line.
We present a tunable LED-based illuminator using custom arrays of Alvarez lenses with commercially available secondary optics. Design methods and characterization of the system performance are discussed.
Dynamic illumination can improve functionality for multiple application areas, including lighting, AR/VR, automotive, medicine, and security. Some applications require a uniform illumination pattern of continuously variable divergence or size for improved functionality. Such dynamic functionality has previously been achieved, for example, by longitudinally moving a source relative to a curved reflector, which can result poor uniformity, or through zoom configurations in which the longitudinal distances between lenses in the system are dynamically adjusted. Advances in high precision manufacturing methods such as diamond machining have facilitated the practical implementation of freeform optical components, enabling new design approaches and concepts for illumination systems. In this paper, we explore the use of arrays of transmissive pairs of freeform surfaces to enable efficient and uniform dynamic illumination in a compact package. This work builds on the Alvarez lens concept, in which a pair of transmissive XY-polynomial freeform surfaces generates variable optical power through lateral relative shifts. Design approaches and simulation results are presented.
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