Assignment 5 for CSE 130/DXARTS 198A

Spring Quarter, 2008

Part 0

Try to identify a group of classmates you would like to work with on the next assignment. Most groups will contain 4 students. After logging into INFACT, look for the link to the group preferences page. Enter any preferences you may have there. This page is confidential; other students will not see your ratings. For your preferences to have an effect, enter them by 4:00 PM on Monday, April 28.

Part 1

Type your answers and past your images for this part (and Part 2) into a file. This should be a Microsoft Word document. Go ahead and include an image for each problem. Turn in your file by uploading it to our CollectIt dropbox and submitting it as Assignment 5. It's due Friday, May 2 at 5:00 PM. The dropbox is at the UW Catalyst web site, linked from here.
  1. Using the "modulator image" method described in Chapter 6, take an abstract pattern, such as stripes, a checkerboard, or a grid, and use a modulator image derived from your own face to create a modulated version. The following example uses vertical stripes as the pattern (one black line every 12 pixels, with white in between), and it uses the red component of each Mona Lisa pixel, divided by 30, as the modular image value. The formula that combines the two images is S1(x + S2(x,y), y). The Mona Lisa has a subtle but noticeable effect on the stripes. Suggestion: set up a Formula Page with separate images for your face, your face turned into a modulator image, the abstract pattern, and your resulting image.
  2. Create a synthesized image containing a pattern of circles. You can arrange the circles in any way you like. They can be colored or not, filled in or not. Their colors can mix when they overlap, or not. Be sure to understand what you are doing. Hint: Work first with a formula to draw a single circle, and practice changing the formula so that you can make it show up in the image at any location, any radius, and with its interior filled with any color or source image pixels that you choose. Then set up several formulas in the Formula Page to combine several circles.
  3. Create an image that uses two (or more) diagonal lines to divide the image image up into areas. Each area should either be a portion of some photograph or some solid color or pattern. If two of these areas are adjacent to one another, they should not be filled with the same color, pattern, or source image. For 2 points of extra credit, use 3 (or more) diagonal lines to divide up your image into areas. Again, no two adjacent areas should be filled the same way. An example with two diagonal lines is shown below.

Part 2

  1. In your teams (which will be defined by Tuesday morning), you will each contribute one (or two) invertible transformation(s) to a set that you will try to make into a transformation group. Each of you should contribute something different, so that the composition of your transformations with others will produce something new.

    Give a name to each transformation in your group, and tell what the inverse of each transformation is.

    Combine all your transformations and create one single formula page containing one window for each basic transformation. If your transformation group contains more than 16 transformations, you don't have to show them all, just 16 of them. Otherwise show all the transformations in your transformation group. Working as a team, make sure your collection of transformations satisfies the properties required for a transformation group; each of you should provide a copy of the justifications (explanation of how each transformation has an inverse, etc.) in your Word file being turned in.

    Be prepared to demo your transformations using the Formula Page.

    (Additional information, added April 30: A worked example of building a group of transformations from the contributions of two people is given in a formula page that you can access from PixelMath. The file is called "Group-of-Transformations-Constructing.pfp". In your own example, you may want to stick to self-invertible transformations, so as to reach closure quickly. Please turn in group "tables" in your Word file, much like those shown here and on the formula page's textual explanation. Note that if you limit your names of transformations to two characters, such as "J1", "C3", etc., it is easier to format the tables.)

    3. Using the method described in Chapter 9, create a stereogram. You should use your own original depth image, perhaps created with methods mentioned at the end of Chapter 8. You should also use your own carrier image, possibly a photo of your own face. Post your stereogram Formula Page, making it available to your group. Ask the members of your group to try computing and viewing your own stereogram. Ask them for suggestions for improving your stereogram. Try to incorporate those suggestions that make sense to you and seem practical. Turn in the stereogram (in a Word file for your whole homework assignment.) and the formulas you used to compute it (in the same file). Explain what you tried to do in creating the stereogram, and how your responded to your team's suggestions. Are you able to see the stereo effect in your stereogram yourself? Could your teammates see it?
Solutions are now available.