An Adaptive Multi-Population Approach for Sphericity Error Evaluation in the Manufacture of Hemispherical Shell Resonators.

The performance of a hemispherical resonant gyroscope (HRG) is directly affected by the sphericity error of the thin-walled spherical shell of the hemispherical shell resonator (HSR). In the production process of the HSRs, high-speed, high-accuracy, and high-robustness requirements are necessary for evaluating sphericity errors. We designed a sphericity error evaluation method based on the minimum zone criterion with an adaptive number of subpopulations.

Analytical reconstructions of full-scan multiple source-translation computed tomography under large field of views.

This paper is to investigate the high-quality analytical reconstructions of multiple source-translation computed tomography (mSTCT) under an extended field of view (FOV). Under the larger FOVs, the previously proposed backprojection filtration (BPF) algorithms for mSTCT, including D-BPF and S-BPF (their differences are different derivate directions along the detector and source, respectively), make some errors and artifacts in the reconstructed images due to a backprojection weighting factor and the half-scan mode, which deviates from the intention of mSTCT imaging. In this paper, to achieve reconstruction with as little error as possible under the extremely extended FOV, we combine the full-scan mSTCT (F-mSTCT) geometry with the previous BPF algorithms to study the performance and derive a suitable redundancy-weighted function for F-mSTCT.

Single-slice rebinning reconstruction method for segmented helical computed tomography.

Recently, to easily extend the helical field-of-view (FOV), the segmented helical computed tomography (SHCT) method was proposed, as well as the corresponding generalized backprojection filtration (G-BPF) type algorithm. Similar to the geometric relationship between helical and circular CT, SHCT just becomes full-scan multiple source-translation CT (F-mSTCT) when the pitch is zero and the number of scan cycles is one. The strategy of G-BPF follows the idea of the generalized Feldkamp approximate cone-beam algorithm for helical CT, i.

Velocity feedback control method of low-frequency electromagnetic vibration exciter based on Kalman filter estimation.

The absence of an appropriate low-frequency vibration velocity detection method to establish feedback control limits the further improvement of the low-frequency vibration performance of electromagnetic vibration exciters. In this article, a low-frequency vibration velocity feedback control method based on the Kalman filter estimation is proposed for the first time to reduce the total harmonic distortion of the vibration waveform. The rationality of establishing velocity feedback control in the velocity characteristic band of the electromagnetic vibration exciter is analyzed.

Discrete fringe phase unwrapping algorithm based on Kalman motion estimation for high-speed I/Q-interferometry.

A discrete fringe phase unwrapping algorithm (DFPUA) based on Kalman motion estimation is proposed to accurately demodulate the phases of I/Q-interferometers with deeply under-sampled quadrature signals, thus to break through the limitations of the Nyquist frequency for high-speed measurement. The basic concept of DFPUA is to estimate the current displacement according to the former motion state, then confirm the actual phase integer number by comparing the estimated phase decimal with the actual phase decimal; in this way, peak acceleration/jerk instead of peak velocity becomes the factor that determines the sampling rate. Two types of DFPUA including velocity estimation and velocity-acceleration estimation are illustrated in detail.