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To improve the quality of the reconstructed image, the common used three reconstruction algorithms in digital holographic microscopy, Fresnel transform algorithm, angular spectrum algorithm, and convolution algorithm, all based on fast-Fourier-transform (FFT) are investigated and compared. By using off-axis lensless Fourier setup the digital hologram of a USAF test target is recorded and reconstructed...
To improve the limitation of applying traditional fault diagnosis method to the diagnosis of multi-concurrent vibrant faults of aeroengine, a new diagnosis approach combining the wavelet transform with fuzzy theory is proposed. A novel method based on the statistic rule is brought forward to determine the threshold of each order of wavelet space and the decomposition level adaptively, increasing the...
According to the point-spread function of off-axis Fresnel digital holographic system with pre-magnification, the wave front deformation introduced by microscope objective is obtained. Using a collimated light as reconstructing wave, the phase aberration introduced by the difference between the reconstructing wave and the reference recording wave is analyzed by using a very simple method, which is...
Power quality (PQ) is becoming prevalent and of critical importance for power industry recently. The fast expansion in use of power electronics devices led to a wide diffusion of nonlinear, time-variant loads in the power distribution network, which cause massive serious power quality problems. The quantitative detection of two distortions of voltage waveform, i.e., voltage sag and voltage swell,...
To improve the limitation of applying traditional fault diagnosis method to the diagnosis of multi-concurrent vibrant faults for aeroengine in aircraft, a novel approach combining the wavelet transform with self-organizing learning array system is proposed. The effective eigenvectors are acquired by binary discrete orthonormal wavelet transform based on multi-resolution analysis. These feature vectors...
Power quality (PQ) has attracted considerable attention from both utilities and users due to the use of many types of sensitive electronic equipment. This paper proposed a novel approach for the PQ disturbances classification based on the wavelet network. Wavelet transform is utilized to extract feature vectors for various PQ disturbances based on the multi-resolution analysis (MRA). These feature...
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