7 results about "Acoustic holography" patented technology

The invention discloses an elevator noise source detection and identification method and device. The method comprises the following steps that acoustic signals of the car top, the car top shaft space, the car bottom and the car bottom shaft space are collected, and vibration signals generated by a traction machine, a guide rail and a car in the elevator running process are collected; estimating time delay between acoustic signals through a generalized cross-correlation algorithm, establishing a nonlinear equation set about a sound source position, and solving to obtain a sound source estimation position; obtaining a sound source position through a beam forming algorithm in combination with the sound source estimation position so as to determine a noise source area; if the position of the sound source points to the interior of the car frame or the interior of the traction machine, the complex sound pressure of an area adjacent to the position of the sound source is measured, and sound field visualization is achieved through near-field acoustical holography so as to locate a noise source area; and judging whether the noise source is an impact sound source or a wind noise source on the same time axis according to the acoustic signal and vibration signal peak conditions of the noise source region. According to the technical scheme, the elevator noise detection efficiency is improved.

The application discloses a high-security double-encryption information communication method based on reconfigurable acoustic holography. The correct information image and the pseudo information image are mixed and then input into a dynamic acoustic holographic neural network to output ciphertext information and an electronic key; a reconfigurable acoustic holographic phase plate carrying the ciphertext information is prepared; based on distance position information, partitioned electrically encoded ultrasonic transducers and the reconfigurable acoustic holographic phase plate are placed; an electrically encoded sequence is input into the transducer; the correct information image is decoded and reconstructed and then visualized on a sound field reconstruction visualization plane; and the reconfigurable acoustic holographic phase plate can be restored for the next encryption information communication. The method can mix the correct information into multiple groups of pseudo information to improve information security, and can encode the electronic key in multiple dimensions to further improve information decoding difficulty, and has a read-once-burn-after feature, so that secondary information leakage can be fundamentally prevented; the method is simple in equipment and difficult in information decryption, and is suitable for high-throughput transmission of text information.

The application discloses a kind of based on the acoustic holography technology's microparticle composite material sound auxiliary manufacturing device and method.Acoustic control module and mixed liquid container lifting mechanism are fixed in water tank inner bottom surface, mixed liquid container lifting mechanism is equipped with mixed liquid container, for accommodating mixed liquid containing microparticle, acoustic control module is set in the lower side of mixed liquid container, for projecting ultrasonic wave to mixed liquid container, to control the spatial arrangement of microparticle in mixed liquid;Layer-by-layer solidification platform lifting mechanism is set to one side of water tank, layer-by-layer solidification platform is installed on layer-by-layer solidification platform lifting mechanism, layer-by-layer solidification platform is set opposite to mixed liquid container, solidification light source is set to mixed liquid container, for the light curing of mixed liquid in mixed liquid container.The application effectively combines acoustic holography technology and 3D printing technology, can arrange microparticle in precursor liquid in the process of material layer-by-layer solidification, and manufacture composite material with arbitrary three-dimensional structured microparticle arrangement.

The invention relates to the technical field of sound power measurement, and discloses a device and a method for testing the sound power of a radial transducer of a circular tube, the device for testing the sound power of the radial transducer of the circular tube comprises a measuring device, an ADC module and a digital processing module, and the measuring device and the ADC module form a signal acquisition module; according to the device disclosed by the invention, a measurement environment with a controllable acoustic boundary is formed by constructing a closed acoustic cavity and combining a sound absorption material and degassing water, echo reflection is effectively inhibited, and the device does not need to depend on facilities such as a large-scale anechoic pool, can be used in a limited space such as a common laboratory or a detection site, and is high in practicability; the transducer positioning mechanism can realize precise positioning and fixing of the circular tube transducer, so that the consistency of a measurement reference is ensured, and the measurement precision is improved; the array type sensors are symmetrically arranged, and the distance can be dynamically adjusted according to the working frequency of the transducer to be detected, so that the spatial sampling requirement of near-field acoustical holography is met, and sound pressure signals can be accurately acquired.

The invention discloses an acoustic metamaterial optimization deployment method based on sound field diagnosis and machine learning. The method comprises the following steps: S1, acquiring and preprocessing multi-source sound field data; s2, three-dimensional sound field feature extraction and reconstruction; s3, sound field state diagnosis and classification; s4, meta-material deployment scheme optimization based on transfer learning: based on the sound field spatial features and the sound field state labels, domain adaptation is performed on strategy library data and current sound field features by using a joint distribution adaptation method, and meta-material layout schemes adapted to the sound field state labels are generated through an optimization algorithm; and S5, performing dynamic deployment and feedback optimization. By deploying the sensor array and fusing the near-field acoustical holography / beam forming technology, three-dimensional space distribution (amplitude and phase) of a sound field can be reconstructed, deep features including spatial textures are extracted, the limitation of traditional single-point or simple array measurement is broken through, and the measurement accuracy is improved. And a comprehensive and accurate physical field state information basis is provided for subsequent intelligent decision making.

The invention discloses a near-field acoustical holography optimization method based on a compressed sensing equivalent source. The near-field acoustical holography optimization method comprises the following steps of 1) performing equivalent processing on a space sound field; step 2), selecting the position and size of a holographic measurement surface in a potential sound source near field, performing equidistant grid division on the holographic surface, and determining a sampling strategy; 3) selecting a certain number of measurement points on the holographic measurement surface in a random manner, constructing a near-field acoustic holographic model based on the compressed sensing equivalent source, and solving an initial sparse solution of the source intensity of the equivalent source by using L1 regularization according to the sound pressure at the measurement points randomly selected in the holographic surface; according to the method, the sparsity of an equivalent source intensity solution can be further improved, the influence of a pseudo source is effectively restrained, the convergence speed of iterative calculation can be increased, and the calculation efficiency is improved.

The application discloses a statistical optimal near-field acoustic holography method based on non-uniform sampling, relates to the technical field of near-field acoustic holography, and overcomes the problems of large error, high cost and low precision of the existing statistical optimal near-field acoustic holography method based on uniform sampling. The method comprises the following steps: step one, non-uniform sampling of a holographic surface; step two, non-uniform sampling in the wave number domain based on the sampling in the step one; and step three, selection of a regularization parameter by means of the L curve method based on the sampling in the step two, so as to realize the statistical optimal near-field acoustic holography method based on non-uniform sampling. The distribution of sampling points of the holographic surface and the wave number domain is set by means of the non-uniform sampling mode, compared with the case of uniform sampling, the method can improve the reconstruction precision, reduce the cost and time of measurement, effectively reduce the number of measurement points and the matrix dimension while ensuring the reconstruction precision, and the sampling method is simple and easy to set, and therefore, the method is more suitable for practical engineering applications.