Due: 4:00 p.m., Monday, 3 September 2007
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Summary: In this assignment, you will use the basic pixel-manipulation techniques you learned in the lab on raster graphics to create simple color mosaics from source images.
Purposes: To get you comfortable working with the basic pixel operations in the GIMP. To help you think about colors.
Expected Time: One hour.
Collaboration: I would prefer that you work in groups of
size three. However, you may work alone, in a group of size two, or a
group of size four. You may discuss this assignment and possible
solutions with anyone you wish. If you discuss this assignment with
people other than group members, make sure to include a citation
I consulted this person, who helped me do
Submitting: Email me your answer. More details below. Each group need submit only one answer.
Warning: So that this assignment is a learning experience for everyone, I may spend class time publicly critiquing your work.
You now know a few simple techniques for dealing with images
and the pixels in those images. In particular, you can load
an image with
image.load, create a new image with
image.new, get the value of a pixel at a particular
image.get-pixel, set the value of a pixel at
a particular location with
image.set-pixel!, and determine
the width and height of an image with
What can you do with this simple suite of procedures? One potentially interesting activity is to build new, simple, images from existing images. For example, you can take a small selection of pixels from one image and use those to build a new image. Such created art is a form of algorithmic art, art created by algorithm, rather than by hand.
Assume that we've defined
image-file as the name of a file
that contains an image. For example, we might have written
(define image-file "/home/rebelsky/glimmer/samples/emily-stalkernet.jpg")
a. Write a series of commands that builds and shows a new 4x4 image, each of
whose pixels is taken from the image stored in
Which pixels should you choose? It is up to you. One natural technique
is to divide the original image into sixteen portions, and take the middle
pixel in each quadrant.
b. Pick at least three images and generate mosaic images from them. Identify one that you find particularly appealing.
I will primarily look to see if you've tried something creative in
choosing the pixels. I will also consider whether the algorithm you've
come up with does anything interesting with
(whatever those are).
Please submit this work via email. The email should be titled CSC151.02 Assignment 03 and should contain your answers to all parts of this assignment. Please send your Scheme work as the body of an email message. Attach one source image and the corresponding result image.
Monday, 3 September 2007 [Samuel A. Rebelsky]
Saturday, 8 September 2007 [Samuel A. Rebelsky]
mosaicafter hearing the term from a pair of students [AM and CM] .
I usually create these pages
on the fly, which means that I rarely
proofread them and they may contain bad grammar and incorrect details.
It also means that I tend to update them regularly (see the history for
more details). Feel free to contact me with any suggestions for changes.
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