Wavelet-Based Semblance Methods to Enhance the Single-Trial Detection of Event-Related Potentials for a BCI Spelling System

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The colors in the image range from blue to red indicating the similarity between the grand average of target responses <svg height="12.1162pt" id="M57" style="vertical-align:-0.04980087pt" version="1.1" viewbox="-0.0498162 -12.0664 18.1013 12.1162" width="18.1013pt" 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="M686 28C612 35 607 44 591 112C563 234 541 360 519 489L489 666L457 658L147 121C100 40 89 36 24 28L17 0H240L250 28C168 34 159 41 190 101L262 237H482C495 180 503 137 510 91C517 47 514 35 441 28L433 0H677L686 28ZM475 280H285L429 541H431L475 280Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,9.135,-5.741)"><path d="M896 675C863 652 826 634 783 634C683 634 549 687 439 687C259 687 128 601 128 473C128 383 196 329 279 329C392 329 469 405 496 541H476C440 428 385 359 286 359C224 359 169 400 169 480C169 566 257 641 382 641C475 641 622 584 731 584C796 584 862 620 907 657L896 675ZM658 553C579 484 521 424 454 277C364 81 295 16 184 16C120 16 82 44 78 79H80C87 68 100 67 108 67C136 67 153 89 153 116S131 165 104 165C69 165 43 139 43 91C43 31 110 -15 191 -15C263 -15 321 6 378 45C463 101 526 197 557 304C588 413 618 487 671 539L658 553Z"></path></g></svg> and the grand average of nontarget responses <svg height="12.1162pt" id="M58" style="vertical-align:-0.04980087pt" version="1.1" viewbox="-0.0498162 -12.0664 18.6311 12.1162" width="18.6311pt" 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="M686 28C612 35 607 44 591 112C563 234 541 360 519 489L489 666L457 658L147 121C100 40 89 36 24 28L17 0H240L250 28C168 34 159 41 190 101L262 237H482C495 180 503 137 510 91C517 47 514 35 441 28L433 0H677L686 28ZM475 280H285L429 541H431L475 280Z"></path></g><g transform="matrix(.0091,0,0,-0.0091,9.135,-5.741)"><path d="M569 131C584 203 591 291 596 391C603 524 609 615 622 658L609 669C545 642 461 523 357 312C267 129 194 14 119 14C104 14 91 21 88 36H91C96 33 101 32 107 32C134 32 149 54 149 77C149 104 128 128 97 128C65 128 38 101 38 62C38 19 71 -15 118 -15C207 -15 274 84 391 315C446 423 501 518 534 563L535 562C518 501 511 401 508 297C504 160 495 63 476 -13H496C588 65 656 224 712 363C783 536 828 621 863 640H866C866 608 894 595 913 595C937 595 956 613 956 641C956 670 935 687 904 687C875 687 853 675 830 650C782 596 735 496 692 394C649 290 605 184 570 131H569Z"></path></g></svg> based on the amplitude and phase information. (b) Normalised standard deviation of <i>D</i> over the scales (between 0 and 1).</div>

Computational Intelligence and Neuroscience

fig1

Figure 1

Figure 1: Wavelet-Based Semblance Methods to Enhance the Single-Trial Detection of Event-Related Potentials for a BCI Spelling System 