Range from Focus

Based on the work of Eric Krotkov

And Jean Paul Martin

Problem statement

Problem statement cont.

Theory of Defocus

The Optical Transfer Function

Wave Aberation

The Object plane, the image plane and the pupil planes

The Wave aberation QQ

A different choice of reference system for wave aberation

Notation

The displacement of the detector plane is = to introduction of wave

aberation by amount

In terms of the amount of defocus

Figure 2. Cross-section of the OTF of a defocused incoherent system

Focus Quality

Focus criterion functions

Focus criterion functions cont.

Implementation

Search Strategy

Fibonacci search technique

The search Algorithm

Computing the range

Thin lens geometry

Computing the range

Algorithm

Limitations

The effect of depth of field

Focus data

Range errors