LMS Sound Camera and Sound Source Localization Fast & Versatile Sound Source Localization

Transcription

1 LMS Sound Camera and Sound Source Localization Fast & Versatile Sound Source Localization Realize innovation.

2 Sound Source Localization What is it about?? Sounds like it s coming from the engine Sound Source Localization Technique to localize and visualize sound at the source With a one-shot measurement using an array of microphones Accelerates troubleshooting and confirms that you work on the right problem Typical applications: Acoustic transparency Locating noise phenomena Comparing variants of components Quantification and ranking of source contributions Page 2

3 Introducing LMS Sound Camera The Digital Microphone Array for Sound Source Localization Industrial fast & easy to use robust design Performant over wide frequency range in far and nearfield Versatile modular design any operating condition for lab and field Insight on Test.Lab with more channels & improved performance Page 3

4 LMS Sound Camera Fast & Versatile Sound Source Localization solution using digital microphone array with integrated electronics Accelerated Troubleshooting with dedicated standalone software LMS Sound Camera Digital Array Software LMS Sound Camera Digital Array Modular microphone array with integrated electronics Center part : 45 mics Short arms: 81 mics Long arms:117 mics Engineering Insight with LMS Test.Lab & LMS SCADAS front-end LMS Test.Lab software data Easy setup. Short time to first result: <5mins Real-time results & reprocessing of recordings In the field testing & comparison of results Report & share results as video & pictures Additional processing using LMS Test.Lab Support of 4 additional sensors on LMS Sound Camera Parallel acquisition with LMS SCADAS using Test.Lab Access to Advanced analysis like: inah, Deconvolution, combustion analysis, Enhanced Productivity using Batch Processing Page 4

5 LMS Sound Camera Digital Array Versatile and Robust All-round array Can be extended with short arms to increase array diameter All-round array optimized for farfield and nearfield Wide angle lens allows viewing entire object at close distance Industrial & Robust Digital microphone array (MEMS) with all electronics integrated Connects directly to PC with a single cable. No frontend required. Robust but light industrial design Wide frequency range 50-20kHz Adapts to many applications Can be extended with long arms to increase array diameter Large diameter offers excellent spatial resolution in low frequency Suited for far-field measurements and quantification applications Page 5

6 LMS Sound Camera Digital Array Modular array with 3 different sizes Center Short Arms Long arms Typical Usage Trouble-shooting, handheld All-round array Advanced, outdoor Typical distance nearfield <0.5m nearfield & far field <1m nearfield & far field (~0.3 to >2m) Typical freq. range 1000*-20kHz 400*-20kHz 200*-10kHz Diameter & mics 30cm with 45 mics 60cm with 81 mics 150cm with 117 mics Dynamic range** 14 db 16 db 12 db Page 6 * With beamforming/nearfield focusing. Can be improved with inah ** Simulated results. Experimental results typically 1-2dB lower.

7 Introducing: Sound Source propagation techniques Page 8

8 Beamforming Basic Principle in time domain S(t) d 1 d 2 P 1 (t) impact Propagation of source signal: ( ) = + d 3 P 2 (t) Back-propagation of measured signals: Back propagated mic signals P 3 (t) ( ) = + + = S 1 (t) + + = S 2 (t) d 13 d 23 d 11 d 21 d 31 P 1 (t) P 2 (t) + + = d 33 P 3 (t) Page 9

9 Beamforming Strength and weakness Beamforming Overview 60cm Measurement distance Distance between speakers 27 cm Poor spatail resolution in low frrequencies 1/3 oct. 500 Hz 1/3 oct Hz Good spatail resolution in high frrequencies 1/3 oct Hz Page 10

10 LMS Sound Camera Digital Array software Dedicated standalone software Easy reporting of results Results can be stored as picture and video Annotated with key data and user comments. raw data can be also be shared for further analysis. Real-time source localization Changes in interesting frequency ranges, averaging and display settings are applied immediately. Allows locating sources quickly. Single sheet application. Analysis and Comparison Reference display and extended display scales For quick side-by-side comparison of results and absolute levels. Allows comparing different product variants and operational conditions. Page 11

11 LMS Sound Camera Digital Array software Designed for movement FARFIELD picture NEARFIELD picture NEARFIELD picture different angle Moving operator Moving from the farfield into the nearfield Real-time nearfield focusing gives best spatial resolution Move around object to locate in space Moving object Assess transient, impulsive operational conditions Analyze recording at high frame rate For balanced and refined source results apply short-time exponentional averaging 25 frames per second high precision Page 12

12 LMS Sound Camera on LMS Test.Lab Measure more data channels tacho Direct connection LMS Sound Camera connects directly to LMS Test.Lab Use 4 additional AC/ICP sensors on LMS Sound Camera Correlate source locations with other analysis results CAN Multi-front-end mode For more channels, parallel acquisition with LMS SCADAS Mobile/ Recorder Combine with advanced tacho, digital sensors, Synchronization from digital irig-b output on SCADAS Mobile. Page 13

13 LMS Sound Camera on LMS Test.Lab Increase engineering insight Improved spatial resolution For source separation and increased spatial resolution in low frequency with inah or Deconvolution Quantify source strength by accurately estimate sound power contribution of sources Leveraging LMS Test.Lab platform Test complex scenarios like engine run-ups, tracked on rotational speed Correlate sound source locations to analyses like orders, sound quality metrics. Improved Productivity Side-by-Side comparison of holograms & contribution spectra Batch processing for systematic test approaches and high demand Fast calculations optimized on graphical card Page 14

14 Improved processing Nearfield Acoustic Holography Used by Beamforming Used by nearfield holography Page 15

15 Improved processing Beamforming Focalization i-nah Beamforming (50cm) Focalization (10cm) inah (10cm) 500Hz 1/3 octave x2 1250Hz 1/3 octave x2 x? High Definition Acoustic Camera 3-in-1 solution Beamforming Focalization inah One measurement in near-field 4000Hz 1/3 octave Page 16

16 Decomposition engine noise using Cyclic Wienerfilter approach Understand contribution combustion noise & other mechanical noises from the engine Target setting & assessment during development cycle Alternative coherence method in time engine noise = domain for cyclic impulsive events combustion noise + residue Page 17

17 Improved processing Rotating Sources Fixed geometry Rotating geometry Page copyright LMS International

18 Improved processing Deconvolution Process In first instance a monopole distribution, in the source plane, is assumed to be as indicated by the beamforming. Step 1: beamforming With each iteration a new source distribution is computed to reduce the Delta between the computed pressure distribution at measurement plane and the measured one. Forward Propagation Delta Step 3 (Iterated): New Source distribution Delta Forward Propagation Page 19 Step 2: Error calculation

19 Improved processing: Deconvolution Example Beamforming Map Between 1kHz and 2kHz Using Far-Field Deconvolution it is possible to improve the localization and increase the dynamic range from 8dB to 20dB Page 20

20 Improved productivity Batch processing Process frequency/rpm ranges for different Loading conditions Configurations All at the same time. Page 21

21 Improved productivity Compare different results Page 22

22 Thank you for your attention!