Lab: DFT of Simple Images

[Exercises] [Workspace]

Purpose: The purpose this experiments is demostrate some DFT of Simple Images.

Activities:

  1. Sinusoidal

    1. Create a sinusoidal image with the Sinusoid operator. Normalize it with the Normalize operator. Extract its FFT seting Unity scaling and Log (Magnitude + 1) using FFT and Magnitudes operators, normalize this result. Inset the two results normalized and display using Inset and Display Image operators.

      1. Glyphs:Input/Output:Generate Data:Sinusoid

        • Parameters:

                    Width:  128
                    Height: 128
                    Num. along Width : 8
                    Num. along Height: 8

      2. Glyphs:Data Manip:Data Conversion:Normalize
      3. Glyphs:Arithmetic:Linear Transforms:FFT

        • Parameters:

                    Scaling Options: Unity scaling

      4. Glyphs:Arithmetic:Complex Operators:Magnitudes
      5. Glyphs:Data Manip:Size & Region Operators:Inset

        • Parameters:

                    Width Coordinate: 129

      6. Glyphs:Visualization:Non-Interactive Display:Display Image

  2. Rectangle

    1. Use the Constant and the Pad operators to create a square object Then proceed as in the previous item to take its FFT and diplay the original and FFT together. You can duplicate several glyphs simultaneously.

      1. Glyphs:Input/Output:Generate Data:Constant

        • Parameters:

                    Width : 8
                    Height: 8
                    Real Constant level: 1

      2. Glyphs:Data Manip:Size & Region Operators:Pad

        • Parameters:

                    Padded Width : 128
                    Padded Height: 128
                    Width  Offset: (128-8)/2
                    Height Offset: (128-8)/2

  3. Gaussian

    1. Use the 2D Gaussian operator and generate gaussian function. Then repeat the same procedure to display its DFT and original images.

      1. Glyphs:Input/Output:Generate Data:2D Gaussian

        • Parameters:

                    Width : 128
                    Height: 128
                    Peak Location (X): 64
                    Peak Location (Y): 64
                    Variance along Width : 4 * 4
                    Variance along Height: 4 * 4

  4. Impulses

    1. Use the Impulse operator:

      1. Glyphs:Input/Output:Generate Data:Impulse

        • Parameters:

                    Width : 128     Num. along Width : 128/8
                    Height: 128     Num. along Height: 128/8
                    Width Spacing : 8
                    Height Spacing: 8


Khoros Workspace
Execute the visual program c5s4dft-simple-images.wk



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