Purpose To investigate the effects of distortion and inhomogeneity correction on brain morphometry with 3T MRI. Materials and Methods The subjects were 16 normal male volunteer (29.4 ± 4.0, 24-38 years old). MRI data were obtained using a 3T scanner (Signa HDx3.0T, GE Healthcare) at the University of Tokyo Hospital. 3D fast spoiled-gradient recalled acquisition in the steady state (3D-FSPGR) wa...

In this study, we evaluated the image distortion of three magnetic resonance imaging (MRI) systems with magnetic field strengths of 0.4 T, 1.5 T and 3 T, during stereotactic irradiation of the brain. A quality assurance phantom for MRI image distortion in radiosurgery was used for these measurements of image distortion. Images were obtained from a 0.4-T MRI (APERTO Eterna, HITACHI), a 1.5-T MRI...

The results of the study features formation and processing signals autodyne short-range radar systems (SRR) with frequency modulation (FM) involving non-linearity characteristic are presented. numerical simulation nonlinear influence on shape spectrum signal is implemented basis mathematical model generator. We have established that even a small this causes significant distortion signal. A meth...

One drawback of OFDM systems is the high peak-to-average power ratio, which imposes strong requirements on the linearity of power amplifiers (PAs). Such linearity requirements translate into high back-off that results in low power efficiency. In order to improve power efficiency, a PA nonlinearity cancellation (PANC) technique is introduced which reduces the nonlinear distortion effects on the ...

This paper presents a fully differential power amplifier (PA) with high efficiency and linearity. To improve the linearity, an optimum gate bias is applied for the cancellation of the nonlinear harmonics. The amplifier delivers a 6 dB of power gain. The signal noise distortion and total harmonic distortion of 55.68 dB and 0.144% has been shown. The compensation characteristics of the circuit ha...

The ability of high performance Radar and Broadband Systems to detect weak targets in presence of strong interferers or clutter is given by their Spurious Free Dynamic Range (SFDR). Although the Signal-toNoise-Ratio (SNR) necessary for detection may be improved by well-known system processing gains, the dynamic range is ultimately limited by distortion terms caused by nonlinear behaviour of rec...

Previous work on camera calibration, and particularly work on self-calibration, has assumed that the camera is well modeled by an ideal, relatively simple, parametric model. Real camera systems, however, diverge signiicantly from a simple pinhole perspective imaging model. Therefore, parametric calibration models are typically extended to include parameters which model distortions from perspect...

There is a rapid development of the performance of state-of-the-art analog to digital converters (ADC). Resolution and sampling rate are increasing continuously. Sampling rates in the high intermediate frequency (IF) range with sufficient dynamic range for communication applications were introduced about the turn of the millennium. Post-correction methods enable fast ADCs with modest linearity,...