Statistics of a vector/scalar field
STAT = statf(F) returns a structure containing some statistics for the
scalar field F.
[STATX,STATY] = statf(F) returns two structures, each containing the
statistics for the X,Y components of the 2-components vector field F.
[STATX,STATY,STATZ] = statf(F) returns 3 structures, each containing
the statistics for the X,Y,Z components of the 3-comp. vector field F.
F is a structure (or structure array) of fields as obtained by loadvec
(vector field) or vec2scal (scalar field).
If F is a single field, the statistics are spatial averages. If F is
an array of fields, the statistics combine spatial and ensemble averages.
The output structure STAT (or STATX, STATY, STATZ) contains the
mean, std, rms: mean, standard deviation and rms.
min, max: minimum and maximum
nfields: number of fields used in the computation
n: number of nonzero elements.
zeros: number of zero elements.
mom: non-centered moments, <s^n>
momabs: non-centered absolute moments, <|s^n|>
cmom: centered moments, <(s-<s>)^n>
cmomabs: centered absolute moments, <|s-<s>|^n>
skewness: normalized 3rd order non-centered moment. (*)
flatness: normalized 4th order non-centered moment. (*)
skewnessc: normalized 3rd order centered moment. (*)
flatnessc: normalized 4th order centered moment. (*)
history: remind for which field statf has been called.
In these definitions, the brackets <> denote both spatial and possibly
... = statf(F,MAXORDER) specifies the maximum order for the moments.
MAXORDER=6 is used by default (although its convergence may not be
guaranteed). The 4 quantities (*) are computed only if MAXORDER>2.
If the fields contain 0 (zero) values, they are considered as
erroneous and are not included into the computations.
v = loadvec('*.VC7');
statrot = statf(vec2scal(filterf(v,1),'rot'));
loadvec, vec2scal, histf, corrf, vsf, specf.
Published output in the Help browser
2005-2021 PIVMat Toolbox 4.20