gabor

type Filter struct {

	// is this filter active?
	On bool

	// how much relative weight does this filter have when combined with other filters
	Wt float32

	// overall gain multiplier applied after filtering -- only relevant if not using renormalization (otherwize it just gets renormed away)
	Gain float32 `default:"2"`

	// size of the overall filter -- number of pixels wide and tall for a square matrix used to encode the filter -- filter is centered within this square -- typically an even number, min effective size ~6
	Size int

	// wavelength of the sine waves -- number of pixels over which a full period of the wave takes place -- typically same as Size (computation adds a 2 PI factor to translate into pixels instead of radians)
	WvLen float32

	// how far apart to space the centers of the gabor filters -- 1 = every pixel, 2 = every other pixel, etc -- high-res should be 1 or 2, lower res can be increments therefrom
	Spacing int

	// gaussian sigma for the length dimension (elongated axis perpendicular to the sine waves) -- as a normalized proportion of filter Size
	SigLen float32 `default:"0.3"`

	// gaussian sigma for the width dimension (in the direction of the sine waves) -- as a normalized proportion of filter size
	SigWd float32 `default:"0.15,0.2"`

	// phase offset for the sine wave, in degrees -- 0 = asymmetric sine wave, 90 = symmetric cosine wave
	Phase float32 `default:"0,90"`

	// cut off the filter (to zero) outside a circle of diameter = Size -- makes the filter more radially symmetric
	CircleEdge bool `default:"true"`

	// number of different angles of overall gabor filter orientation to use -- first angle is always horizontal
	NAngles int `default:"4"`
}