Maximum Likelihood Estimation of Wave Front Slopes using a Hartmann-type Sensor.

Abstract

Current methods for estimating the wave front slope at the pupil of a telescope equipped with a Hartmann-type wave front sensor (H-WFS) are based on a simple centroid calculation of the intensity distributions (spots) recorded in each subaperture of the H-WFS. The centroid method does not include any knowledge concerning correlation properties of the slopes over the subapertures or the amount of light collected by the telescope and diverted to the H-WFS for wave front reconstruction purposes. This thesis devises a maximum likelihood (ML) estimation of the spot centroids by incorporating statistical knowledge of the spot shifts. The light level in each subaperture and the relative spot size is also employed by the shift estimator. The shift estimator is found to be unbiased and is upper bounded by the mean squared error performance exhibited by the classical centroid technique.

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Document Details

Document Type
Technical Report
Publication Date
Dec 01, 1995
Accession Number
ADA305562

Entities

People

  • Scott A. Sallberg

Organizations

  • Air Force Institute of Technology

Tags

Communities of Interest

  • Materials and Manufacturing Processes
  • Sensors

DTIC Thesaurus Topics

  • Adaptive Optics
  • Atmospheric Motion
  • Detection
  • Detectors
  • Distortion
  • Estimators
  • Focal Planes
  • Geometry
  • Maximum Likelihood Estimation
  • Optical Detection
  • Probability
  • Probability Density Functions
  • Random Variables
  • Shape
  • Statistics
  • Stochastic Processes
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Atmospheric Science / Meteorology, specifically Wind Wave Turbulence.
  • Computer Vision.
  • Statistical inference.

Technology Areas

  • Space
  • Space - Space Objects