signal processing - Finding local maximum between two peak or points using MATLAB -

signal processing - Finding local maximum between two peak or points using MATLAB -

i have intensity points marked pinkish in above plot, , these stored in variable , given as

intensity_info =[ 35.9349 46.4465 46.4790 45.7496 44.7496 43.4790 42.5430 41.4351 40.1829 37.4114 33.2724 29.5447 26.8373 24.8171 24.2724 24.2487 23.5228 23.5228 24.2048 23.7057 22.5228 22.0000 21.5210 20.7294 20.5430 20.2504 20.2943 21.0219 22.0000 23.1096 25.2961 29.3364 33.4351 37.4991 40.8904 43.2706 44.9798 47.4553 48.9324 48.6855 48.5210 47.9781 47.2285 45.5342 34.2310 ];

i have info of point a, b , c calculated :

[maxtab, mintab] = peakdet(intensity_info, 1); % maxtab has , b info , % mintab has c info

peakdet.m matlab code can found here: (http://www.billauer.co.il/peakdet.html). want calculate point d (where there sight increment in intensity value i.e. if come downwards point intensity decreases @ point d there slight increment in intensity). seen graph below point c can lie in left of point d , in case if come downwards point b intensity decrease , @ d there slight increment in intensity. intensity values below graph below given as:

intensity_info =[29.3424 39.4847 43.7934 47.4333 49.9123 51.4772 52.1189 51.6601 48.8904 45.0000 40.9561 36.5868 32.5904 31.0439 29.9982 27.9579 26.6965 26.7312 28.5631 29.3912 29.7496 29.7715 29.7294 30.2706 30.1847 29.7715 29.2943 29.5667 31.0877 33.5228 36.7496 39.7496 42.5009 45.7934 49.1847 52.2048 53.9123 54.7276 54.9781 55.0000 54.9781 54.7276 53.9342 51.4246 38.2512];

and point ,b , c calculated in same manner above.

how can calculate point d in these cases?

i'm not matlab literate, if 'tabs' subtables, perhaps can manipulate them create other subtables... (i repeat, illiterate)

left_of_graph = part of graph c right_of_graph = part of graph c b left_delta = fraction of difference between a's y-value , c's y-value right_delta = fraction of difference between c's y-value , b's y-value [left_maxtab,left_mintab] = peakdet(left_of_graph,left_delta) [right_maxtab,right_mintab] = peakdet(right_of_graph,right_delta)

i do have experience peak analysis, help, not answer, problem. can find peaks want, doesn't mean info worth squinting at. noise , imperfect resolution real. happy hunting!

ps might scan points higher both neighbors in whole band. gauranteed miss none of 'true' maxima, give more 'false' maxima can count (although info looks pretty smooth!).

matlab signal-processing