title: Phase Correction-Adaptive Line Enhancement for Noise Reduction of Low-Field NMR.
abstract: The amplitude of low-field nuclear magnetic resonance (NMR) is weak, and the echo is buried in the noise. The reduction of noise is critical to accurately extract echo amplitude. Phase correction-adaptive line enhancement (PC-ALE) is proposed to noise suppression based on the principle of ALE and NMR spin-echo characteristics. The echo amplitude is calculated after two-stage processes; phase shift from time-delay and filter tap would be compensated effectively in frequency domain. Simulation and experiments show that PC-ALE has prominent performance on noise suppression, envelope recovery, as well as the correction of the phase shift. The amplitude from the method of sample average nearby the middle of the echo is more accurate than the maximum peak when the PC-ALE is applied to noise suppression of spin-echo.
authors.affiliation: Key Laboratory of Shale Gas Exploration, Ministry of Land and Resources, Chongqing Institute of Geology and Mineral Resources, 177-9 Yangtze River 2 Road, Yuzhong, Chongqing, 400042 China ; Chongqing Shale Gas Research Centre of State Key Laboratory of Petroleum Resource and Prospecting, Chongqing, 400042 China.
authors.forename: Qingming
authors.initials: Q
authors.lastname: Xie
authors.forename: Lizhi
authors.initials: L
authors.lastname: Xiao
authors.forename: Lijun
authors.initials: L
authors.lastname: Cheng
authors.forename: Junfeng
authors.initials: J
authors.lastname: Liu
authors.forename: Hongying
authors.initials: H
authors.lastname: Li
authors.forename: Feng
authors.initials: F
authors.lastname: Deng