Imaging through Scattering Media with a Learning Based Prior

2020 ◽  
Vol 2020 (14) ◽  
pp. 306-1-306-6
Author(s):  
Florian Schiffers ◽  
Lionel Fiske ◽  
Pablo Ruiz ◽  
Aggelos K. Katsaggelos ◽  
Oliver Cossairt
Keyword(s):  
Optimization Problem ◽  
Autonomous Driving ◽  
Scattering Media ◽  
Photon Scattering ◽  
Point Spread ◽  
Spread Function ◽  
Radiative Transport Equation ◽  
Spatio Temporal ◽  
Transient Imaging

Imaging through scattering media finds applications in diverse fields from biomedicine to autonomous driving. However, interpreting the resulting images is difficult due to blur caused by the scattering of photons within the medium. Transient information, captured with fast temporal sensors, can be used to significantly improve the quality of images acquired in scattering conditions. Photon scattering, within a highly scattering media, is well modeled by the diffusion approximation of the Radiative Transport Equation (RTE). Its solution is easily derived which can be interpreted as a Spatio-Temporal Point Spread Function (STPSF). In this paper, we first discuss the properties of the ST-PSF and subsequently use this knowledge to simulate transient imaging through highly scattering media. We then propose a framework to invert the forward model, which assumes Poisson noise, to recover a noise-free, unblurred image by solving an optimization problem.

scholarly journals Spatio-temporal point-spread function of fMRI signal in human gray matter at 7 Tesla

NeuroImage ◽  
2007 ◽  
Vol 35 (2) ◽  
pp. 539-552 ◽  
Author(s):  
Amir Shmuel ◽  
Essa Yacoub ◽  
Denis Chaimow ◽  
Nikos K. Logothetis ◽  
Kamil Ugurbil
Keyword(s):  
Gray Matter ◽  
Point Spread Function ◽  
7 Tesla ◽  
Fmri Signal ◽  
Point Spread ◽  
Spread Function ◽  
Spatio Temporal

An Approach to Measuring the Point Spread Function of the Confocal Raman Microscope

2020 ◽  
Vol 74 (10) ◽  
pp. 1230-1237
Author(s):  
Xiang Ding ◽  
Yanzhe Fu ◽  
Jiyan Zhang ◽  
Yao Hu ◽  
Shihang Fu
Keyword(s):  
Image Quality ◽  
Size Effect ◽  
Point Spread Function ◽  
Performance Indicator ◽  
Signal To Noise Ratio ◽  
Polystyrene Microspheres ◽  
Point Spread ◽  
Spread Function ◽  
Confocal Raman

The confocal Raman microscope (CRM) is a powerful tool in analytical science. Image quality is the most important performance indicator of CRM systems. The point spread function (PSF) is one of the most useful tools to evaluate the image quality of microscopic systems. A method based on a point-like object is proposed to measure the PSF of CRM, and the size effect of spherical objects is discussed. A series of phantoms are fabricated by embedding different sizes of polystyrene microspheres into polydimethylsiloxane matrix. The diameters of microspheres are from 0.2 µm to 5 µm. The phantoms are tested by measuring the PSF of a commercial CRM whose nominal lateral resolution is about 1 µm. Results of the PSF are obtained and the accuracy of resolution is used to evaluate the size effect of the microspheres. Experimental results are well consistent with theoretical analysis. The error of the PSF can be decreased by reducing the diameter of the microsphere but meanwhile the signal-to-noise ratio (S/N) will be lowered as well. The proper diameter of microspheres is proposed in consideration of the trade-off between the S/N and the measurement error of the PSF. Results indicate that the method provides a useful approach to measurement of the PSF and the resolution of the CRM.

scholarly journals Controlled-source interferometric redatuming by crosscorrelation and multidimensional deconvolution in elastic media

Geophysics ◽  
2011 ◽  
Vol 76 (4) ◽  
pp. SA63-SA76 ◽  
Author(s):  
Joost van der Neut ◽  
Jan Thorbecke ◽  
Kurang Mehta ◽  
Evert Slob ◽  
Kees Wapenaar
Keyword(s):  
Wave Propagation ◽  
Velocity Model ◽  
Seismic Sources ◽  
Elastic Media ◽  
Virtual Source ◽  
Controlled Source ◽  
Point Spread ◽  
Spread Function ◽  
Wavefield Decomposition

Various researchers have shown that accurate redatuming of controlled seismic sources to downhole receiver locations can be achieved without requiring a velocity model. By placing receivers in a horizontal or deviated well and turning them into virtual sources, accurate images can be obtained even below a complex near-subsurface. Examples include controlled-source interferometry and the virtual-source method, both based on crosscorrelated signals at two downhole receiver locations, stacked over source locations at the surface. Because the required redatuming operators are taken directly from the data, even multiple scattered waveforms can be focused at the virtual-source location, and accurate redatuming can be achieved. To reach such precision in a solid earth, representations for elastic wave propagation that require multicomponent sources and receivers must be implemented. Wavefield decomposition prior to crosscorrelation allows us to enforce virtual sources to radiate only downward or only upward. Virtual-source focusing and undesired multiples from the overburden can be diagnosed with the interferometric point-spread function (PSF), which can be obtained directly from the data if an array of subsurface receivers is deployed. The quality of retrieved responses can be improved by filtering with the inverse of the PSF, a methodology referred to as multidimensional deconvolution.

scholarly journals Development of a beam propagation method to simulate the point spread function degradation in scattering media

2019 ◽  
Vol 44 (20) ◽  
pp. 4989 ◽  
Author(s):  
Xiaojun Cheng ◽  
Yunzhe Li ◽  
Jerome Mertz ◽  
Sava Sakadžić ◽  
Anna Devor ◽  
...  
Keyword(s):  
Point Spread Function ◽  
Beam Propagation Method ◽  
Beam Propagation ◽  
Scattering Media ◽  
Point Spread ◽  
Spread Function

Calibrating an area-detector diffractometer: integral response

1990 ◽  
Vol 428 (1874) ◽  
pp. 181-214 ◽  
Keyword(s):  
Differential Absorption ◽  
Fast System ◽  
Imaging Geometry ◽  
Area Detector ◽  
Point Spread ◽  
Spread Function ◽  
Satisfactory Method ◽  
Integral Response ◽  
Imaging Detectors

The quality of diffraction data measured with electronic area-detectors is improved by correcting for non-uniformities in the response of the detector. Many detectors are actually much more uniform than they appear because much of the perceived non-uniformity is an artefact of the distortions in their imaging geometry and of the methods of illumination during calibration. Indeed, every known correction reduces the perceived non-uniformity. Our inability to illuminate the detector uniformly with radiation of the same wavelength as is used during data-collection is a particular worry because of differential absorption. The tails of the point-spread function also perturb the apparent response, particularly near to the edges of the imaging area. These problems are difficult to compensate, so there is no completely satisfactory method of determining the true response of real detectors. However, this does not prevent us from making calibrations of usable accuracy. Although this paper applies to all types of area-detector, the discussion is centred mainly on the ENRAF-NONIUS fast system, which is a commercially available television diffractometer, calibrated using software written by the present author. Calibrating the response of imaging detectors is a general problem, and many of the techniques expounded here are of wide applicability.

scholarly journals TIME DEPENDENCE OF THE POINT SPREAD FUNCTION OF A FOUR-WAVE CONVERTER IN A WAVEGUIDE WITH THERMAL NONLINEARITY

2017 ◽  
Vol 20 (10) ◽  
pp. 130-139
Author(s):  
E.V. Vorobieva ◽  
V.V. Ivakhnik ◽  
M.V. Luneva
Keyword(s):  
Time Dependence ◽  
Point Spread Function ◽  
Wave Interaction ◽  
Single Mode ◽  
Initial State ◽  
Thermal Nonlinearity ◽  
Point Spread ◽  
Spread Function ◽  
Wave Converter

The time dependence of a quality of wave-front reversal has been analyzed at four-wave interaction in a waveguide with thermal nonlinearity. The influence of waveguide parameters and mode structure of pumping waves on time dependence character has been investigated. It has been shown, that increases of number of single-mode pumping waves lead to decreases of difference in point spread function width in steady state and initial state.

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