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BARTLETT,

Section: TRIANGLE (HAMMING,)
Updated: HANNING,
Index

NAME

bartlett, hamming, hanning, rectangle, triangle,parseWindowName - circularly symmetric windowfunctions for filters and parsing of window function name

SYNTAX

#include <xite/ideal.h>

double bartlett (double n, int size);
double hamming (double n, int size);
double hanning (double n, int size);
double rectangle (double n, int size);
double triangle (double n, int size);
window_type parseWindowName(char *name);

DESCRIPTION

The bartlett,hamming,hanning(von Hann),rectangle(box, boxcar) and trianglefunctions returnfunction values for the various windows, at a certaindistance n.sizeis the diameter of the windowfunction.

Window functions are typically used to multiply with a filterin the spatial domain.

These functions should only be called when
0 <= n < size

Outside this interval, the functions should be consideredequal to zero.

rectangleis given by
w(n)=1.0

bartlettis given by
2n/(size-1), n<=(size-1)/2
w(n)=
2-2n/(size-1), n>(size-1)/2

triangleis given by
2(n+1)/(size+1), n<=(size-1)/2
w(n)=
2-2(n+1)/(size+1), n>(size-1)/2

triangleis almost the same as bartlett,but triangledoes not include zeros at the end-points.

hammingis given by
w(n)=0.54-0.46*cos(2 Pi n/(size-1))

hanningis given by
w(n)=0.5-0.5*cos(2 Pi (n+1)/(size+1))

hanningis sometimes defined slightly different. Thisversion does not include zeros at the end-points.

parseWindowNamereturns a symbolic integer value for variousforms of window name.Legal forms of nameare

Full name  Short name  Number
-----------------------------
rectangle      r         RECTANGLE
bartlett       b         BARTLETT
triangle       t         TRIANGLE
hamming        hm        HAMMING
hanning        hn        HANNING

RETURN VALUE

Function value.

AUTHOR

Trond Muri Sřrensen, Svein Bře

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