Wavelets

The Wavelet tool is a widget application program that graphically demonstrates the image compression capabilities of Wavelet Transforms.

Wavelet Tool Display

A group of menus at the top of the display controlling the program options.

A 256x256 byte display of the uncompressed image.

A 256x256 byte display of the compressed image.

A visual display of the wavelet basis of both the original image and the compressed image.

A graph showing the ratio between actual values in the wavelet basis (Y) and the percentage of compression (X) that would result if the Y value was used as the threshold for compression.

An optional 256x256 byte display window that displays the difference between the compressed and uncompressed images. The difference image has been byte scaled.

Menu Options

File Menu

Select "Open" to select a new image. A list of files will appear. Click on one of the listed items to select a new image.

Options Menu

Select "4 coefficients" to compute the wavelet basis using 4 Daubechies coefficients.

Select "12 coefficients" to compute the wavelet basis using 12 Daubechies coefficients.

Select "20 coefficients" to compute the wavelet basis using 20 Daubechies coefficients.

Select "Show difference image" to create a pop-up window that shows the difference between the original an compressed images.

View Menu

Select "Colors..." to launch the XLOADCT application, which allows you to select a different color table for the animation.

About Menu

Features

Percentage Slider

Adjust the slider to change the amount of compression used. Higher percentage compression values mean smaller data sets.

You can also adjust the compression percentage by positioning the mouse pointer in the "Adjust compression" plot, holding down the left mouse button, and dragging the vertical line that appears in the plot.