Accurate Image‐Based Estimates of Focus Error in the Human Eye and in a Smartphone Camera

Estimation of focus error is a key consideration in the design of any advanced image‐capture system. Today's contrast‐based auto‐focus algorithms in digital cameras perform more slowly and less accurately than the human eye. New methods for estimating focus error can close this gap. By making use of optical imperfections, like chromatic aberration, these new methods could significantly improve the performance of digital auto‐focusing techniques.

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