TITLE:
A Simple Model for On-Sensor Phase-Detection Autofocusing Algorithm
AUTHORS:
Przemysław Śliwiński, Paweł Wachel
KEYWORDS:
Phase Detection Autofocus; On-Sensor Circuit; Formal Model; Cross-Correlation; Stochastic Approximation
JOURNAL NAME:
Journal of Computer and Communications,
Vol.1 No.6,
November
26,
2013
ABSTRACT: A simple model of the phase-detection
autofocus device based on the partially masked sensor pixels is described. The
cross-correlation function of the half-images registered by the masked pixels
is proposed as a focus function. It is shown that—in such setting—focusing is equivalent to searching of the cross-correlation function
maximum. Application of stochastic approximation algorithms to unimodal and
non-unimodal focus functions is shortly discussed.