The method Integrate calculates the definite integral of a signal represented by an equidistant series of values which are stored in the vector. The parameters BoundLow and BoundHigh specify the boundaries of the integration and may be fractional within a valid range of 1.0 and NrOfElem. The integration method has to specified by the parameter Method and provides the following approximations:
imSimple 
calculates the sum of the reference points within the boundaries 
imTrapezoidal 
uses the linear trapezoidal method to estimate the integral 
imSimpson 
uses a parabolic interpolation to estimate the integral 
Please note that all parts of the signal outside the array of reference points (which are, by definition, all vector elements between the boundaries) are linearly interpolated (irrespective of the type of integration).
For mathematical details on Simpson's rule please see the following literature:
 Press et al., Numerical Recipes in Fortran 77, 1997, p. 126128
 G. Boole, A Treatise on the Calculus of Finite Differences, 1860, p. 38
