#
vcm

## F2Quiver

The call for this function is:-

## vcm.F2Quiver(clip[ , int frad = 32][,int test = 0][, int morph = 0][, float gamma = 0.05], int fspec = [spec1][,......] ] )

clip: RGB or YUV or Gray constant format input. Green or Y component only processed.
frad: radius of filter in space domain. It can vary from 16 to 1/4 of smaller frame dimension in steps of 4. Note that large frad increases time of processing.
morph: set to one for homomorphic process.This mode during test improves display. For regular processing refer literature for need and filtering.
test: set to 1 for test mode
gamma: from 0.0001 to 5.0. used if test is set to 1.
fspec: [ array of 1 to 12 integer sets, each set has 5 values(symmetry, type, freq1, freq2, degree). At least one set must be specified.
:: symmetry: 1. circular, 2 Horizontal, 3.vertical, 4. Fan line through origin, 5. points in the spectrum. Note that in spectrum opposite quadrants are symetrical, so defining in one automatically defines in the opposite quadrant. Depending on similarity, the parameter definition changes.
:: Type: 1 low cut (or high pass) 2. Hicut (or low freq pass) 3.band pass 4. band stop 5. notch. For point symmetry only notch is designed.
:: freq1: freq of cut or notch, or low freq of pass or stop, or angle1 in degrees (0 to 89, 91 to 179)of fan. X freq coordinate of point. Freq values are positive in range 0 to 255, NYQUIST being 512.
:: freq2: higher freq of band or angle 2 of fan spread. Angle 2 should be more than angle1.(angle2 and angle1 both must be either between 1 to 89 degrees or 91 to 179 degree range.) Some value must be specified even if not applicable. freq2 value of 2 to 255, or for point Y freq coord of -255 to 255
:: degree: degree of sharpness of filter. 1 to 24. If set to 1 , gaussian, otherwise butterworth filters are designed.

This function does a 2D transform of each frame, applies designed filter and inverse transforms for output. Upto 12 Butterworth or Gauss 2D filters can be specified. These are cascaded and applied. To enable determining frequencies and symmetries test facility is provided. In test mode the frequency spectrum and designed filters are displayed. In the 2d frequency spectrum, one may notice symmetries of image elements and noise. Homomorphic filtering is an option. The filter radius frad specifiess filter radius in image (spatial) domain. Required padding to eliminate wrap aound effect is done.

This transforms data into frequency domain. The freq domain filter functions require FFTw3f 32 bit dll or for 64 bit FFTw3f 64 bit dll, of fftw.org being available in path.