ECE 563 Assignment 8

Images for this assignment may be downloaded from impro8.zip.

  1. Find the autocorrelation and selfconvolution images of an unsymmetric shape of your choice. (See example)

  2. Use grayscale images of two class members as input. Generate their Fourier transforms. Interchange the amplitude and phase terms of the two images and generate the corresponding inverse Fourier transform images.

  3. Crop out a rectangular sample from xruler.tif, showing a millimeter scale and such that the image dimensions are powers of two (e.g. 256 x 16). Determine the ruler frequency from the Fourier transform of this sample (measure the distance from the central peak (DC term) to the first strong harmonic peak). Compare the results to those determined by measuring the period (scale) directly.

  4. Rotate a small image using imrotate. Verify that the Fourier transform image rotates by the same amount by showing the rotated image and its Fourier Transform. Demonstrate with an animation.

  5. For the images of letters of the alphabet, shown below, prepare an array of images showing the cross correlation and cross convolution images of each letter with itself and the other two letters. The diagonal of this array will be autocorrelations or self convolutions.

      

  6. Filter the spurious patterns in the lincoln image.

  7. Use an angle-selective low-pass filter on the fabric image below to remove the structure of the individual strands and fibers. Note that most of the strands have frequencies in the horizontal and vertical directions, whereas the weave is oriented along the 45-degree axes.

  8. Prepare powerpoint tutorials on the following Matlab topics:

    Submit powerpoint, published MATLAB, and original MATLAB and images. Only one submission needed per group. Use Isidore messages for submission.

Maintained by John Loomis, last updated 29 March 2016