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## Lab: Wavelets: Frequency Analysis

[Exercises] [Workspace]

Purpose: The purpose of this lab is to visualize and interpret the 2D magnitude spectra of a wavelet analysis performed on an image.

Activities:

1. Read the image $DIP/data/gull.kdf, display it, take a one-level forward wavelet transform, determine its spectrum, and display the results. Use the operators User defined, Display Image , FFT, and Wavelet Transform. Use the file $DIP/data/daub2hd.ascii as the "Highpass Filter Coefficient" file, and $DIP/data/daub2ld.ascii as the "Lowpass Filter Coefficient" file.

   1. Glyphs:Input/Output:Data Files:User defined
   2. Glyphs:Wavelet:Linear Transforms:Wavelet Transform
   3. Glyphs:Arithmetic:Linear Transforms:FFT
   4. Glyphs:Visualization:Non-Interactive Display:Display Image

2. Extract the four quadrants of the wavelet transform, find the spectrum of each individually, and display the results. Use the operators Extract, FFT, and Display Image.

   1. Glyphs:Data Manip:Size & Region Operators:Extract
   2. Glyphs:Arithmetic:Linear Transforms:FFT
   3. Glyphs:Visualization:Non-Interactive Display:Display Image
   4. Interpret the resultant spectra.

Exercises

1. Perform the same experiment, but with different images.

Khoros Workspace
Execute the visual program c8s3W-freq-decomposition.wk