mlAnalyzeArrayEtendue

 Analyze the etendue across a sensor array

 ISA = mlAnalyzeArrayEtendue(ISA,[method = 'centered'],[nAngles = 5])

   Calculate the etendue across the sensor surface given the current
   microlens properties. The calculation can be performed assuming the
   microlens is 

     optimal:  at the optimal position
     centered: at the pixel center
     nomicrolens:  absent.

   These conditions are established by the method argument.  The case of
   no microlens is also called 'vignetting' as it refers to only the loss
   of light due to the combination of the imaging (taking) lens and the
   tunnel of the pixel.

   We compute optical efficiency of the microlens by calculating the ratio
   of the etendue with and without the microlens present (see below).

   The nAngles specifies the number of chief ray angles that are used to
   estimate the function across the array.  This number is typically small
   (default = 5) because the etendue function is very smooth and can be
   estimated from just a couple of values.

 Example:
   ISA = vcGetObject('ISA');
   ISA = mlAnalyzeArrayEtendue(ISA,'optimal');
   optimalE = sensorGet(ISA,'sensorEtendue');

   ISA = mlAnalyzeArrayEtendue(ISA,'nomicrolens');
   nomlE = sensorGet(ISA,'sensorEtendue');
   mesh(optimalE ./ nomlE);
 
   tic, ISA = mlAnalyzeArrayEtendue(ISA,'centered',5); toc;  plotSensorEtendue(ISA)

   ISA = mlAnalyzeArrayEtendue(ISA,'centered',5);
   plotSensorEtendue(ISA);

 Copyright ImagEval Consultants, LLC, 2003.