A) The first thing you should do is create a character. You can do this by using a computer
tool to sketch the character or their outline. Or, you can download a character of your choice from
the Web. Save the character as a .jpeg file to keep things simple. You might also want to figure
out how to fill the character to create the desired coloration, etc.
As an example for you, I have placed the file CharlieBrown.jpg in the Matlab Files module on
Canvas. If you read in the picture using the command:
>>
CB=imread(’CharlieBrown.jpg’);
(you might have to switch to the directory with the .jpg file to make it work), the net result is that
matrix CB will hold the RGB values for the Charlie Brown picture (it is actually a 3-D array, but
don’t worry about that for now). Next, run the CB matrix through the Jpeg2pointsConverter2
script using the command:
>>
CBout = Jpeg2pointsConverter2(CB,220);
Note that 220 is the THRESHOLD value used by the Jpeg2pointsCoverter2 script. When you
choose your own character, you will have to see if the image looks OK and the number of total
points in the output matrix (CBout here) is only a few thousand. If you don’t like the resulting
image or it has too many points, try again with a different THRESHOLD value (higher THRESH-
OLD values give fewer points). You should read the help info at the top of Jpeg2pointsConverter
to see more details.
(B) For this first stage of your animation you should take your character and transform
it by each of these
required matrix transform elements
: (a) rotations, (b) shifts, (c) shears,
reflections, or rescalings, (d) transformations or alterations of your character such as a morph.
Show a before and after plot for each case, and record the transformation matrices (or morphing
rules if you use them).
(C) Make your character walk off the screen along some vector path. You can do this in
several ways, but in your write-up, be sure to explain the methods you used (for example, you can
use the homogeneous coordinates approach that was used in the moveN.m script; or, you can use
the matrix outer product approach that will be described in class).
This next part is more complicated, since it involves having your character away from the origin,
sitting somewhere in the “scene.” Then, since most of our transformations are defined around
the origin, you must (mathematically) transport your character to reference coordinates about the
origin, where you will transform it before placing it back in the scene. For your write-up of this
part, you should include your matlab code and explain the transformations that you used.
(D) For this more advanced part of your animation, I want you to write a matlab func-
tion/script that can take in a character located anywhere in a scene, transform it to reference
coordinates where you can perform transformations, then do the transformations and put the char-
acter back in the scene. You should take your character and transform it multiple times within
a
for loop
by at least two of these
matrix transform elements
: (a) rotations, (b) shears,
reflections, or rescalings, (c) other transformations/alterations or morphs of your character. Show
some plots to capture the action and include them in your write-up.