XWPL(1)

NAME
xwpl - X-Window Wavelet Packet Laboratory

SYNOPSIS
xwpl [-toolkitoption ...]

DESCRIPTION
The xwpl program provides an X11 interface to the libawa.a library of M. Victor Wickerhauser. The program can read one-dimensional files, zoom in on portions of the input signal. The user can choose among a number of quadrature mirror filters (QMFs) to do a wavelet-packet transform. There is a graphical representation of the signal in the time-frequency space using Phase's Heisenberg box representation.

CONTROLS
The open button paps up the File Browser to select an input file. See OPENING A FILE below for details. The quit button exits xwpl. The info button displays the copyright notice. Press it again to make the notice disappear.

QMF LIST
The QMF list allows the user to choose a QMF family for the transforms. The waveform of the mother wavelet for the selected filter is displayed in the QMF plot widget.

WIDTHS LIST
The widths list allows the user to select a window size for the current window.

BASIS TYPE LIST
The basis type list allows the user to select the kind of basis desired. At the moment, the following are available: best-basis (basis of minimum entropy), best level (basis from the level in the wavelet packet expansion with minimum entropy) and wavelet basis.

FUNCTION PANES
There are 4 function panes in the xwpl window. The mouse buttons behave as in a text widget in each of these panes: the first mouse button starts the selection, and the third mouse button extends the selection.

  Window Pane
All the wavelet packet transforms apply to a window of the input signal. This window is displayed inside the window pane. Selecting a smaller portion of the window will zoom to the selection.

  Original Pane
The original signal pane shows the entire input signal. The currently active window is highlighted. Selecting a portion of the signal will change the currently active window to the nearest window of width a power of two.

  Coefficients Pane
The coefficient pane show the amplitude of the wavelet packet coefficients, sorted in decreasing order of magnitude. The steeper the fall, the more efficiently the wavelet packet selected approximates the input signal.

  Reconstruction Pane
The reconstruction pane show the signal reconstructed from the coefficients selected in the coefficient pane. The selection is automatically adjusted to an heuristically computed threshold, but can be changed by the user. To restore the default selection, simply click on the QMF list again.

FILE FORMAT
The input files to xwpl are ASCII text files of floating-point numbers separated by newlines or other whitespace. This representation is inefficient, but lends itself easily to manipulation using the standard Unix utilities such as awk(1).

OPENING A FILE
The File Browser allows an X11 user to select a file by typing the path or by browsing in directory listings and selecting entries with the mouse.

It is inspired by the Macintosh(tm) SFGetFile dialog box. All the usual key bindings can be used in the text widget, except for Return and Control-M, which are equivalent to pressing the OK button.

Each filename is preceded by an icon that describes the type of the file.

The File Browser is in total control until is pops down. No other controls will be active.

XWPL SUBWIDGET RESOURCES
The subwidgets of Xwpl can be customized. Here are the reources that can be used:

  Function Plot widget (class Funplot)

foreground (class Foreground)
    The color with which to draw the function itself and the title. Default is red.

axis (class Axis)
    The color with which to draw the horizontal axis (if visible). Default is black.

selection (class Selection)
    The color with which to highlight a selection. Default is pink.

pad (class Pad)
    The number of pixels with which to "pad' the function plot. Default is 5.

penWidth (class PenWidth)
    The width of the strokes to use when plotting the function. Default is 3.

titleFont (class TitleFont)
    The font to use for the function title. Default is the fixed font.

XWPL SUBWIDGET ACTIONS

OPTIONS
All the standard X Toolkit options are supported.

WIDGET HIERARCHY
The hierarchy of the xwpl application:

Xwpl  xwpl
	Form  topBox
		Command  open
		Command  quit
		Command  info
		List  qmfList
		List  widthList
		List  basisList
		Funplot  qmfBox
		Phase   phase
		Funplot  window
		Funplot  original
		Funplot  cost
		Funplot  reconstruct
	TopLevelShell infoPopup
		Text  infoText

The hierarchy of the File Browser:

TopLevelShell  fileBrowserShell
	Browser  file
	Scrollbar  fileListScrollbar
	Ilist  fileList
	Command  ok
	Command  cancel
	Text  text

ENVIRONMENT
No environment variables are used yet.

LIMITATIONS
Too many to mention.

BUGS
If you find a bug, please send a bug report to majid@math.yale.edu.

AUTHOR
Copyright (C) 1993 Fazal Majid

Copyright (c) 1989-1993 Yale University, Fast Mathematical Algorithms & Hardware Inc. Fazal Majid, R.R. Coifman, Y. Meyer, M.V. Wickerhauser