Statistically Optimized Near-Field Acoustic Holography Using Prolate Spheroidal Wave Functions

<div>(a) The amplitude of the normal velocity on the thin plate at 1000 Hz. (b) Sound pressures on the hologram surface <svg height="11.927pt" id="M261" style="vertical-align:-3.291101pt" version="1.1" viewbox="-0.0498162 -8.6359 10.918 11.927" width="10.918pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M485 501C480 550 475 615 475 650H42V622C119 616 127 606 127 525V126C127 44 119 34 41 28V0H311V28C220 34 212 43 212 126V584C212 612 216 615 244 615H318C382 615 404 608 420 587C435 568 445 541 455 497L485 501Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,5.486,3.132)"><path d="M509 90L493 118C465 91 427 70 418 70S409 77 415 103L469 327C494 429 466 451 436 451C412 451 387 444 356 427C307 400 222 342 160 264H158L246 667C253 701 252 710 243 710C228 710 169 680 87 673L83 644H117C155 644 160 640 149 588L24 -4L32 -12C57 -4 86 4 108 9L143 187C198 275 324 386 375 386C394 386 399 367 385 311L331 87C315 22 322 -12 351 -12C387 -12 452 24 509 90Z"></path></g></svg> with SNR = 30 dB at 1000 Hz. The dots represent the sampling measurements. (c) Benchmark sound pressures on three reconstruction surfaces <span class="nowrap"><svg height="11.8174pt" id="M262" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -8.6359 10.5526 11.8174" width="10.5526pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M485 501C480 550 475 615 475 650H42V622C119 616 127 606 127 525V126C127 44 119 34 41 28V0H311V28C220 34 212 43 212 126V584C212 612 216 615 244 615H318C382 615 404 608 420 587C435 568 445 541 455 497L485 501Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,5.486,3.132)"><path d="M389 0V32C297 38 291 46 291 118V635C234 613 175 595 109 583V556L161 554C203 552 207 547 207 497V118C207 46 201 38 110 32V0H389Z"></path></g></svg>,</span> <span class="nowrap"><svg height="11.8174pt" id="M263" style="vertical-align:-3.1815pt" version="1.1" viewbox="-0.0498162 -8.6359 10.5526 11.8174" width="10.5526pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M485 501C480 550 475 615 475 650H42V622C119 616 127 606 127 525V126C127 44 119 34 41 28V0H311V28C220 34 212 43 212 126V584C212 612 216 615 244 615H318C382 615 404 608 420 587C435 568 445 541 455 497L485 501Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,5.486,3.132)"><path d="M414 144C384 79 371 75 317 75H135L276 221C367 316 408 376 408 465C408 570 327 635 237 635C179 635 131 609 100 575L42 494L67 471C94 510 138 565 205 565C277 565 321 517 321 435C321 348 258 270 195 195C146 137 88 81 33 26V0H411C423 44 433 88 446 135L414 144Z"></path></g></svg>,</span> and <span class="nowrap"><svg height="11.927pt" id="M264" style="vertical-align:-3.291101pt" version="1.1" viewbox="-0.0498162 -8.6359 10.5526 11.927" width="10.5526pt" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><g transform="matrix(.013,0,0,-0.013,0,0)"><path d="M485 501C480 550 475 615 475 650H42V622C119 616 127 606 127 525V126C127 44 119 34 41 28V0H311V28C220 34 212 43 212 126V584C212 612 216 615 244 615H318C382 615 404 608 420 587C435 568 445 541 455 497L485 501Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,5.486,3.132)"><path d="M290 377C321 398 342 415 358 430C378 450 389 473 389 502C389 578 329 635 238 635H237C184 635 137 610 109 578L64 515L88 493C112 529 154 573 208 573S303 542 303 482C303 409 233 370 141 341L149 308C165 313 190 319 215 319C272 319 341 283 341 193C342 98 292 43 222 43C163 43 122 72 96 94C88 101 79 100 70 94C61 87 47 73 46 60C44 47 48 37 62 23C76 10 118 -12 165 -12C238 -12 430 62 430 223C430 297 379 359 290 375V377Z"></path></g></svg>.</span></div>

Shock and Vibration

fig9

Figure 9

Figure 9: Statistically Optimized Near-Field Acoustic Holography Using Prolate Spheroidal Wave Functions 