Constrained least squares filtering in high resolution PET and SPECT imaging

1990 ◽  
Vol 37 (2) ◽  
pp. 647-651 ◽  
Author(s):  
G.D. Hutchins ◽  
W.L. Rogers ◽  
P. Chiao ◽  
R.R. Raylman ◽  
B.W. Murphy
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Spect Imaging ◽  
Constrained Least Squares

Iterative least-squares migration for high-resolution angle gathers

2020 ◽  
Author(s):  
Lian Duan ◽  
Alejandro Valenciano ◽  
Nizar Chemingui
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Least Squares Migration

Constrained least-squares

1978 ◽  
Vol 3 (1) ◽  
pp. 43-47 ◽  
Author(s):  
S.A. Coons
Keyword(s):  
Least Squares ◽  
Constrained Least Squares

Least‐squares inversion of in‐situ sonic Q measurements: Stability and resolution

Geophysics ◽  
2004 ◽  
Vol 69 (2) ◽  
pp. 378-385 ◽  
Author(s):  
Aristotelis Dasios ◽  
Clive McCann ◽  
Timothy Astin
Keyword(s):  
High Resolution ◽  
Least Squares ◽  
Instantaneous Frequency ◽  
Spectral Ratio ◽  
Full Waveform ◽  
Multiple Measurements ◽  
Sandstone Reservoir ◽  
Gas Bearing

We minimize the effect of noise and increase both the reliability and the resolution of attenuation estimates obtained from multireceiver full‐waveform sonics. Multiple measurements of effective attenuation were generated from full‐waveform sonic data recorded by an eight‐receiver sonic tool in a gas‐bearing sandstone reservoir using two independent techniques: the logarithmic spectral ratio (LSR) and the instantaneous frequency (IF) method. After rejecting unstable estimates [receiver separation <2 ft (0.61 m)], least‐squares inversion was used to combine the multiple estimates into high‐resolution attenuation logs. The procedure was applied to raw attenuation data obtained with both the LSR and IF methods, and the resulting logs showed that the attenuation estimates obtained for the maximum receiver separation of 3.5 ft (1.07 m) provide a smoothed approximation of the high‐resolution measurements. The approximation is better for the IF method, with the normalized crosscorrelation factor between the low‐ and high‐resolution logs being 0.90 for the IF method and 0.88 for the LSR method.

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