Finding two minimum Values in a graph?

Hi, I am trying to find two points on the graph, I've searched around but could not find anything specific relating to what I am searching, I am trying to find two X values on the graph of both signals at both points when they're at the lowest in respect to yaxis, I have been trying to generate a code for one, this is what I got so far. Thanks in advance..

indexmin = find(min(laserC) == laserC);
xmin = T(indexmin)
ymin = laserC(indexmin)
indexmax = find(max(laserC) == laserC);
xmax = T(indexmax)
ymax = laserC(indexmax)

output:

xmin =
   27.2940
   27.3860
ymin =
    1.0195
    1.0195

But I would like also know how to determine the other xmin value which would be around 30ish.

Answer 1

[Star Strider]

Use the Signal Processing Toolbox findpeaks function with the negative of laserC’:

[pks,pkt] = findpeaks(-laserC, T);
pks = -pks;                                             % Correct Amplitudes

The times ‘pkt’ do not need to be corrected.

See the documentation on findpeaks for all the details.