Acoustic camera is an imaging device used to locate sound sources and to characterize them. It consists of a group of microphones — also called microphone array — that are simultaneously acquired to form a representation of the location of the sound sources.

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General principles
Acoustic camera generally consists of a microphone array and an optical camera. The microphones are acquired simultaneously or with known relative time delays to be able to use the phase difference between the signals. As the sound propagate in the medium (air) at a finite known speed, a sound source is perceived by the microphones at different time instants and at different sound intensities that depend on both the sound source location and the microphone location. One popular method to obtain an acoustic image from the measurement of the microphone is to use beamforming: By delaying each microphone signal relatively and adding them, the signal coming from a specific direction  is amplified while signals coming from other directions are canceled. The power of this resulting signal is then calculated and reported on a power map at a pixel corresponding to the direction. The process is iterated at each direction where the power needs to be computed.

Applications
There are many applications of the acoustic camera, with most focusing on noise reduction. The camera is frequently applied to improve the noise emission of vehicles (such as cars, airplanes]) and trains, structures — such as wind turbines.

Acoustic cameras are not only used to measure the exterior emission of products but also to improve the comfort inside cabins of cars,train or airplanes. Spherical acoustic camera are preferred in this type of application because the three-dimensional placement of the microphone allow to localize sound sources in every directions.

Troubleshooting of faults that occur in machines and mechanical parts can be accomplished with an acoustic camera. To find where the problem lies, the sound mapping of a properly functional machine can be compared to one of a dysfunctional machine.

A similar setup of the acoustic camera can be used to study the noise inside passenger carts during train operation. Alternatively, the camera can be set up outside, in an area near the train tracks, to observe the train as it goes by. This can give another perspective of the noise that might be heard inside the train. Additionally, an outside setup can be used to examine the squealing of train wheels caused by a curve in the tracks.

Acoustic camera used for Great Wall Motor Engine noise reduction design,we found that 500Hz noise is from engine body,1000Hz noise from belt pulley,2500Hz noise from pipe system.

more applictions please see Acoustic camera solutions or contact: info@teclab.cn

advanced Acoustic camera  64 spiral system technical specification:
Product Model：AACS-64spiral;
Aperture  (Duty Ratio)：2m（6%）; Number of models switching: 2;
Number of Microphones (specification)：64（1/2 inch measurement level）;
Sources’ Separation Lower Frequency Limit：200Hz/400Hz;
No Virtual Image Upper Frequency Limit：3000Hz/12kHz;
Measurement Frequency Range：：2Hz-18kHz;
Positioning Accuracy (1kHz &1m)：1°、1cm;
Spatial  Resolution (1kHz &1m)：2°、2cm;
Sound to Light Offset(1kHz)：0.3°;
Sound Imaging Pixels: 418k;
Frame Rate: 4-25 fps;
Dynamic Range of Microphone: 120/140dB,160/180dB;
Dynamic Rang of Array：10~140dB,50~160dB;
Gain of Array (SNR addition):22dB(±35°);
Signal  Enhancement：36dB;
Viewing Angle(FOV)：±28º~±35 º﹠±27º;
Operating Temperature, Allowed Humidity：-40℃～+65℃：<99%;
Electromagnetic Compatibility (EMC)：10-10MHz, 200v, Military Level;
Detection Range：0.5m～200m;
Normal Operating Voltage/Total Current：±5v/(+260mA,-150mA);
Total Power Consumption (Allowed Voltage)：4w（2.5V～6V）;
Time of a ±6v Battery Continuous supplying：≥10 hours;
Weight & Size of Array Body, Before and After Packaging：35kg & 109cm×109cm×27cm;
Size of Array Body Packing Box：15kg，102cm×102cm×24cm.