從點分布不均的二維區域中提取曲線/曲面

Question

我有代表兩條曲線的填充區域的數據。 見圖像。 我需要處理表面曲線（或多或少像正弦信號），但我看不到僅提取最大點和最小點的方法。 重要的是要知道這些點不是均勻分布或等效分布的，並且沒有計算出的采樣頻率。

這是我用來表示圖像的數據示例（我的矩陣更大）。

Example = reshape([0.016536 0.036051 0.055566 0.075081 0.094596 0.114111 0.127121 0.134927 0.140131 0.153141 0.153141 0.160947 0.167451 0.172655 0.172655 0.179160 0.180461 0.185665 0.185665 0.188060 0.193797 0.198675 0.198675 0.198675 0.198675 0.198675 0.205180 0.211685 0.212986 0.212986 0.218190 0.218190 0.218190 0.219491 0.219491 0.231200 0.231200 0.232501 0.232501 0.237705 0.237705 0.237705 0.237705 0.237705 0.239331 0.247463 0.250715 0.250715 0.252341 0.252341 0.257220 0.257220 0.257220 0.257220 0.257220 0.257220 0.257220 0.270230 0.270230 0.270230 0.270230 0.270230 0.276735 0.276735 0.276735 0.276735 0.276735 0.276735 0.278361 0.286493 0.289745 0.289745 0.296250 0.296250 0.296250 0.296250 0.296250 0.296250 0.296250 0.306007 0.309260 0.309260 0.312512 0.315765 0.315765 0.315765 0.315765 0.315765 0.328775 0.330401 0.332027 0.332027 0.335280 0.335280 0.348290 0.348290 0.349591 0.366178 0.367805 0.387320 0.403582 0.408461 0.425049 0.427976 0.442612 0.445864 0.447491 0.465379 0.465379 0.465379 0.483268 0.484894 0.496603 0.504409 0.510914 0.510914 0.517419 0.517419 0.523924 0.523924 0.523924 0.523924 0.523924 0.530429 0.530429 0.530429 0.536934 0.536934 0.536934 0.543439 0.543439 0.543439 0.543439 0.543439 0.543439 0.549944 0.549944 0.549944 0.549944 0.549944 0.556449 0.556449 0.556449 0.558075 0.562954 0.562954 0.562954 0.562954 0.562954 0.562954 0.569459 0.569459 0.569459 0.569459 0.575964 0.575964 0.575964 0.575964 0.575964 0.582469 0.582469 0.582469 0.582469 0.582469 0.582469 0.588974 0.588974 0.588974 0.588974 0.588974 0.595479 0.595479 0.595479 0.595479 0.601984 0.601984 0.601984 0.601984 0.601984 0.601984 0.608489 0.608489 0.608489 0.608489 0.614994 0.614994 0.614994 0.616620 0.621499 0.621499 0.621499 0.621499 0.621499 0.628004 0.628004 0.628004 0.629630 0.634509 0.634509 0.641014 0.641014 0.641014 0.641014 0.641014 0.641014 0.647519 0.647519 0.654024 0.654024 0.654024 0.660529 0.660529 0.660529 0.660529 0.667034 0.667034 0.673539 0.673539 0.675165 0.680044 0.680044 0.686549 0.686549 0.688175 0.693053 0.699558 0.699558 0.699558 0.706063 0.712568 0.719073 0.719073 0.720700 0.732083 0.735336 0.740215 0.751598 0.753225 0.771113 0.790628 0.810143 0.829658 0.849173 0.868688 0.888203 -0.053191 -0.053191 -0.053191 -0.053191 -0.053191 -0.046647 -0.033559 0.044970 0.195483 0.290372 0.035154 0.457245 0.182395 0.624118 0.018794 0.300188 0.457245 0.705918 0.133315 0.810811 0.015522 0.957864 0.604486 0.470333 0.352540 0.234747 0.781175 0.005706 1.085473 0.143131 0.483421 0.365628 0.260923 0.873446 0.637860 1.020033 -0.007382 1.179707 0.119572 0.745183 0.627390 0.509597 0.391804 0.274012 0.879336 0.005706 1.137825 1.020033 1.271978 0.094050 0.902240 0.784447 0.666654 0.548861 0.431069 0.313276 0.221659 1.281794 1.164002 1.046209 0.103866 0.005706 0.797535 0.679742 0.561949 0.444157 0.326364 0.208571 0.938232 1.203266 1.085473 0.054786 0.918600 0.784447 0.666654 0.548861 0.431069 0.313276 0.221659 1.006944 0.094050 0.005706 0.830255 0.719007 0.601214 0.483421 0.365628 0.247835 0.012250 0.133315 0.575038 0.457245 0.352540 0.260923 0.005706 0.300188 0.143131 0.015522 0.130043 0.025338 0.005706 0.094050 0.021411 0.172579 0.005706 0.077690 0.211843 0.234747 0.116954 0.012250 0.015522 0.143131 -0.155278 -0.328041 -0.485098 -0.596346 -0.131719 -0.720683 -0.249512 -0.367305 -0.838476 -0.956269 -1.067518 -0.485098 -0.602890 -1.191854 -0.131719 -0.720683 -1.309647 -0.249512 -0.367305 -0.838476 -0.956269 -1.074062 -1.427440 -0.485098 -0.602890 -1.191854 -1.545233 -1.656481 -0.131719 -0.720683 -1.309647 -1.741554 -0.249512 -0.367305 -0.838476 -0.956269 -1.074062 -1.427440 -0.485098 -0.602890 -1.191854 -1.545233 -0.131719 -0.720683 -1.309647 -1.663026 -1.780818 -0.249512 -0.367305 -0.838476 -0.956269 -1.074062 -1.427440 -0.485098 -0.602890 -1.191854 -1.545233 -1.761186 -0.131719 -0.720683 -1.309647 -1.672842 -0.249512 -0.367305 -0.838476 -0.956269 -1.074062 -1.427440 -0.485098 -0.602890 -1.191854 -1.532145 -0.131719 -0.720683 -1.427440 -1.329279 -0.249512 -0.367305 -0.838476 -0.956269 -1.074062 -0.485098 -0.602890 -1.309647 -1.211486 -0.131719 -0.720683 -0.249512 -0.367305 -0.838476 -0.956269 -1.074062 -1.191854 -0.485098 -0.602890 -0.131719 -0.720683 -1.054429 -0.249512 -0.367305 -0.838476 -0.949725 -0.485098 -0.602890 -0.131719 -0.818844 -0.740315 -0.249512 -0.367305 -0.485098 -0.720683 -0.622523 -0.131719 -0.249512 -0.367305 -0.583258 -0.504730 -0.131719 -0.249512 -0.485098 -0.386937 -0.131719 -0.357489 -0.269144 -0.249512 -0.151351 -0.125175 -0.085911 -0.059735 -0.053191 -0.053191 -0.033559 -0.033559 ],[245    2]);

對於我可以使用的 function 或方法的任何提示，我將不勝感激。 我嘗試了一些功能，如 mesh 或 findpeaks 但沒有用。

Answer 1

您可以嘗試使用movmax function。信號處理專家可能有更好的方法，但這是我的嘗試：

% First compute the moving maximum of the absolute value
movMaxAbs = movmax(abs(Example(:,2)),10);
% To correct the sign, we need something like this
signCorrection = sign(smoothdata(Example(:,2)));
plot(Example(:,1), Example(:,2), Example(:,1), movMaxAbs .* signCorrection);