Holographic Sound Field Inspection System

An Industrial Acoustic Intelligent Inspection Solution—
From Macroscopic Panoramic Perception to Microscopic Holographic Insight

I. Industry Challenges and System Positioning

In the field of industrial equipment operation and maintenance and fault diagnosis, engineers have long faced a dual challenge spanning “macroscopic panoramic perception” and “microscopic holographic insight”:

• Macroscopic layer: the need to rapidly lock onto anomalous sources in large-scale equipment or complex scenarios; yet strong background noise within large spaces (80–90 dB) and multi-source coupling make abnormal-noise signals extremely easy to submerge;

• Microscopic layer: the need to precisely localize the specific excitation point of core components; yet constrained by the physical diffraction limit, conventional techniques remain stuck at “meter-level blur” in localization accuracy, making root-cause diagnosis difficult to achieve.

The GroupCore Acoustic Holographic Sound Field Inspection System was created precisely to resolve this dual predicament, fusing two core technologies—the holographic sound field inspection instrument and NAH2048 large-array near-field acoustic holography—to build a complete technical closed loop from “macroscopic panoramic perception” to “microscopic holographic insight.”

II. Macroscopic Panoramic Perception: Holographic Sound Field Inspection Instrument

2.1 Core Technical Principles

Spherical microphone array, enabling native blind-zone-free coverage

Adopting a distinctive spherical microphone array design and abandoning the conventional motorized pan-tilt rotation scheme, it achieves one-shot native coverage of hemispherical space (360°×180°), physically realizing blind-zone-free sound field acquisition over the entire spherical space. This fundamentally resolves the pain points of conventional acoustic imaging cameras—a limited viewing angle (< 90°), a small coverage area, and numerous viewing blind zones.

AI multi-source Blind Source Separation (BSS), precisely extracting anomalous signals amid strong noise

Integrating full-chain AI multi-source blind source separation technology, it requires no prior information and extracts the original source signals solely from the observed mixed signals. Amid the 80–90 dB strong background noise of industrial sites, it precisely separates out all types of interfering signals, bringing weak anomalous signals “to the surface” and transforming “chaos” into “clarity.”

2.2 Cross-Industry Application Value

A single deployment enables panoramic mapping of global acoustic hotspots, with work efficiency rising dramatically:

III. Microscopic Holographic Insight: NAH2048 Large-Array Near-field Acoustic Holography

3.1 Core Technical Principles

Near-field Acoustic Holography (NAH)—breaking through the diffraction limit

Conventional far-field measurement can capture only “propagating waves” that travel to the far field, and its resolution is limited by wavelength; NAH, by contrast, performs dense-array measurement in the near field of the sound source, capturing not only propagating waves but also the evanescent waves that carry fine vibration information about the source. Evanescent waves exist only in the near field and decay rapidly with distance, yet they carry the source’s sub-wavelength fine-structure information. By capturing this “vanishing” wave, NAH breaks through the Rayleigh diffraction limit, achieving reconstruction resolution that is not constrained by wavelength and carrying localization accuracy across a revolutionary leap from “meter-level blur” to a “centimeter-level fine origin.”

NAH2048—ultra-large planar array with synchronous acquisition

Equipped with an ultra-large planar microphone array of 2048 high-density acquisition channels, its “wrapping” coverage achieves millisecond-level synchronous, full-area acquisition over the surface of the component under test. A single trigger completes full-field data acquisition, reducing the hours required by conventional point-by-point scanning to just a few seconds. The captured hologram-plane sound pressure data, containing evanescent-wave information, is reconstructed into a complete three-dimensional sound field through an inverse mathematical transform, ultimately outputting a high-resolution 3D sound field contour map.

3.2 Cross-Industry Application Value

Specializing in low-frequency source tracing and precision measurement of complex structures:

IV. Combining Both Strengths: Building a Closed Holographic Sound Field Intelligent Inspection Loop

The two core technologies complement each other, building a complete technical path from problem discovery to root-cause localization:

Fusing the two builds a 100% digital, visualized closed holographic sound field intelligent inspection loop—from full-domain acoustic scanning to precise quantitative analysis—providing a complete technical path from problem discovery to root-cause localization for equipment condition monitoring and fault diagnosis in the power, oil & gas, petrochemical, machinery manufacturing, and other industries.