3results about How to "Suppress aliasing" patented technology

The present application relates to acoustic equipment technology, and discloses a micro loudspeaker, which comprises a loudspeaker assembly and a sound absorption assembly.The loudspeaker assembly comprises a diaphragm and a paper tube, and the paper tube is provided with a second ball groove at the end thereof.The sound absorption assembly comprises a fixed cavity and an induction unit, and the induction unit is used for increasing the sound absorption coefficient at low frequency and suppressing the sound absorption coefficient at high frequency.At low frequency, the current of the induction coil is increased, the magnetic field intensity of the induction coil is increased, the viscosity of the magneto-rheological fluid is increased, and the sound absorption coefficient is increased.At high frequency, the current of the induction coil is reduced, the magnetic field intensity of the induction coil is reduced, the viscosity of the magneto-rheological fluid is reduced, the sound absorption coefficient is reduced, and the sound absorption requirement of the target frequency band is accurately matched.The present application further discloses a loudspeaker assembly which is composed of one or more micro loudspeakers.

The invention discloses a cryoablation needle target area frosting state identification method based on image processing, and relates to the technical field of cryoablation needles. Constructing a target area original image sequence under the unified space-time coordinate system; outputting corresponding degradation stage information; obtaining a high-fidelity target region clear image sequence; aggregating the signal subspace features through a channel gating mechanism to obtain a signal enhancement feature image set; generating a target area multi-scale semantic feature tensor; outputting an initial frosting probability distribution diagram of the target area; performing form constraint segmentation optimization to obtain a frosted area mask with a consistent form; and a time sequence stable frosting area mask sequence is obtained, a frosting state dynamic evolution model is constructed, and early warning information is displayed in real time. According to the method, the problem of feature submerging caused by mixed noise is effectively inhibited, and the recognizable degree and stability of bottom layer structure information of a target area are remarkably improved in a low-temperature imaging environment.

This invention relates to the field of optical interferometry, specifically to a method for measuring the interferometric surface shape of a binary diffraction grating by separating the upper and lower surfaces. This method addresses the problem that traditional Fizeau interferometry cannot achieve independent measurement of each surface when measuring periodic diffraction structures due to fringe aliasing, phase jumps, and signal mixing. The method is based on acquiring a phase-shifted interferogram sequence using a standard Fizeau interferometer. After suppressing diffraction noise and reconstructing clear fringes using a three-dimensional Fourier transform and spatial low-pass filtering, a phase-shifting algorithm is used to extract the continuous phase. To separate the upper and lower surfaces, the zero-frequency component in the time domain is further extracted to obtain a reflectivity distribution map, and a segmentation mask is automatically generated based on its step intensity characteristics, ultimately achieving independent phase separation and surface shape reconstruction for each surface. This invention requires no changes to the interferometer hardware, effectively overcomes the difficulties of fringe aliasing and phase unpacking, achieves high-precision and stable measurement of binary diffraction gratings, and possesses strong noise resistance and good engineering applicability.