Assignment 2 for CSE 130/DXARTS 198A

Spring Quarter, 2008

Type your answers into a plain text file. (If you want to, type them into a Microsoft Word document that uses only one font and text size and style; then save the file as plain text -- .txt). Turn in your file by uploading it to our CollectIt dropbox and submitting it as Assignment 2. The dropbox is at the UW Catalyst web site, linked from here.

Part 1

Do all exercises at the end of Chapter 2.

Part 2

(Something more creative and open-ended.)

A.

Upload an image of your choice to the INFACT file management facility on Socrates. To upload an image, from the main INFACT page, select the link "Manage Files", and then use the "Browse" button and "Upload" button to select and upload your image file.

The image should be something you wouldn't mind sharing with the rest of the class. After you have uploaded the image, answer the question: What file name did you give your image?

B.

Identify some key feature in the image that you will try to keep recognizable, such as the number of trees in front of the house, the fact that there is a person in the picture, etc. Then use PixelMath to produce a minimum-resolution version of that image in which that feature is still recognizable. Explain this minimum resolution in terms of Nyquist sampling.

C.

Create a high-contrast monochrome version of your image. The result should be an image with only black pixels and white pixels. (Work from the original high-resolution version of the image --- not the result from Part B.) Try to maximize either the clarity of the representation or the aesthetic appeal of it. Explain both what operations you performed and how you chose them.

D.

Create a re-colored version of the image by applying a PixelMath formula that alters the colors of the pixels. Try to come up with a formula that makes the resulting image visually most interesting.

Note that one convenient type of formula for such a task involves a call to calculator function "RGB". For example,

RGB(Green1(x,y), Blue1(x,y), Red1(x,y))

performs a sort of "rotation" of the color components, so that the amount of green in a pixel becomes the amount of red in the pixel, and the amount of blue becomes the amount of green, and the amount of red becomes the amount of blue.

You may also choose to work with formulas involving hue, saturation, and value of the colors.

When you are satisfied with your formula, write that down as your answer, and then describe either what you were trying to do or what you did as you created it.

 

Solutions prepared by Cam.