Effects of aberrations on image reconstruction of data from hybrid intensity interferometers

Murray-Krezan, Jeremy; Crabtree, Peter N.

doi:10.1117/12.919189

Cited by 2 publications

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“…(17), we point out that the intensity covariance measurement provides information on the magnitude of the Fourier transform of the absorption profile of the object of interest. Thus it is possible that with a Gerchberg-Saxton type reconstruction algorithm [10][11][12][13][14], one may be able to reconstruct projection shapes of arbitrary dark objects using this signature. In addition, it is clear from our analysis in Sec.…”

Section: Discussionmentioning

confidence: 99%

“…However, it is easy to show (see the Appendix) that in both the laboratory demo and especially the stellar imaging cases the intensity variation across the speckle size due to the shadow is vanishingly small compared to the speckle variation itself. This is because the sharp shadow condition [20] is opposite to assumption (13). Therefore, the correlation measurement indeed provides the information unavailable from the intensity measurements.…”

Section: A Disk-shaped Source and Objectmentioning

confidence: 99%

“…For instance, the correlation function full width at half maximum (FWHM), which is also frequently referred to as the speckle or transverse coherence width, yields the angular size of the light source. Moreover, the intensity distribution across a spatially nonuniform source determines the shape of the intensity-correlation function (van Cittert-Zernike theorem) and can be extracted from it [10][11][12][13]. This approach has been suggested, e.g., for imaging of solar spots [14], tidal and rotational distortions, limb darkening [7,8], and other stellar phenomena.…”

Section: Introductionmentioning

confidence: 99%

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Intensity interferometry for observation of dark objects

Strekalov

Erkmen

2013

Phys. Rev. A

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We analyze an intensity interferometry measurement carried out with two point-like detectors facing a distant source (e.g., a star) that may be partially occluded by an absorptive object (e.g., a planet). Such a measurement, based on the perturbation of the observed covariance function due to the object's presence, can provide information of the object complementary to a direct optical intensity measurement. In particular, one can infer the orientation of the object's transient trajectory. We identify the key parameters that impact this perturbation and show that its magnitude is equal to the magnitude of the intensity variation caused by the same object. In astronomy applications, this value may be very small, so a differential measurement may be necessary. Finally, we discuss the signal-to-noise ratio that may be expected in this type of measurement

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Section: Discussionmentioning

confidence: 99%

Section: A Disk-shaped Source and Objectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intensity interferometry for observation of dark objects

Strekalov

Erkmen

2013

Phys. Rev. A

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Cramer–Rao bounds for intensity interferometry measurements

Holmes

Calef

Gerwe³

et al. 2013

Appl. Opt.

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The question of signal-to-noise ratio (SNR) in intensity interferometry has been revisited in recent years, as researchers have realized that various innovations can offer significant improvements in SNR. These innovations include improved signal processing. Two such innovations, the use of positivity and the use of knowledge of the general shape of the object, have been proposed. This paper investigates the potential gains offered by these two approaches using Cramer-Rao lower bounds (CRLBs). The CRLB on the variance of the positivity-constrained maximum likelihood (ML) estimate is at best 1/4 of the variance of the unconstrained estimator. This is compared to the positivity-constrained ML estimator, which delivers a best-case variance reduction of only (1-1/π)/2=34.1%. The gains offered by prior knowledge depend on the quality of such information, as might be expected from optimal weighting of such data with the measured data. Furthermore, biases are induced by the application of constraints, and these biases can eliminate some or all of the advantage of lower variances, as found when considering the total root-mean-square error. A form of CRLB for variance is presented that properly incorporates prior information.

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Effects of aberrations on image reconstruction of data from hybrid intensity interferometers

Cited by 2 publications

References 0 publications

Intensity interferometry for observation of dark objects

Intensity interferometry for observation of dark objects

Cramer–Rao bounds for intensity interferometry measurements

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