CVT_MOVIE2
Animated CVT Algorithm

CVT_MOVIE2 is a MATLAB program which animates the generation of a Centroidal Voronoi Tessellation (CVT) dataset.

The program proceeds to create a series of PNG files, each containing one frame of the animation. It is possible to create an animation by using software such as Apple QuickTime.

Usage:

cvt_movie2 ( n, sample_num, frame_num, rebirths )

N

the number of points to generate; the default is N = 100.

SAMPLE_NUM

the number of sampling points: the default is SAMPLE_NUM = 100,000.

FRAME_NUM

the number of frames to create. the default is FRAME_NUM = 30.

REBIRTHS

set NONZERO if the program is to randomly "kill" one generator on each step and create a new one. the default is REBIRTHS = 1.

Animation:

You can see an MP4 animation (no "rebirths").

You can see an MOV animation (with "rebirths").

Related Data and Programs:

The MP4 format was used for the animation.

Reference:

1. Franz Aurenhammer,
   Voronoi diagrams - a study of a fundamental geometric data structure,
   ACM Computing Surveys,
   Volume 23, Number 3, pages 345-405, September 1991,
   ../../pdf/aurenhammer.pdf
2. Qiang Du, Vance Faber and Max Gunzburger,
   Centroidal Voronoi Tessellations: Applications and Algorithms,
   SIAM Review, Volume 41, 1999, pages 637-676.

Source Code:

• ch_is_digit.m is TRUE if a character represents a digit.
• cvt_movie2.m the main program for the creation of the movie.
• digit_inc.m increments a character that represents a digit.
• file_name_inc.m "increments" a file name that has numeric characters in it.
• s_len_trim.m returns the length of a string to the last nonblank.
• timestamp.m prints the current YMDHMS date as a timestamp.
• voronoi_new.m an improved version of the voronoi command, draws a Voronoi diagram of a given set of points.

Examples and Tests:

Here are the sequence of 100 PNG files created by a run of the program. Here we forced all the points to start initially in a small area near (0.25,0.50). Notice how the pattern first expands slowly, then adjusts to the constant random "rebirth" of one point every step.

• cvt_movie2_0001.png .
• cvt_movie2_0002.png .
• cvt_movie2_0003.png .
• cvt_movie2_0004.png .
• cvt_movie2_0005.png .
• cvt_movie2_0006.png .
• cvt_movie2_0007.png .
• cvt_movie2_0008.png .
• cvt_movie2_0009.png .
• cvt_movie2_0010.png .
• cvt_movie2_0011.png .
• cvt_movie2_0012.png .
• cvt_movie2_0013.png .
• cvt_movie2_0014.png .
• cvt_movie2_0015.png .
• cvt_movie2_0016.png .
• cvt_movie2_0017.png .
• cvt_movie2_0018.png .
• cvt_movie2_0019.png .
• cvt_movie2_0020.png .
• cvt_movie2_0021.png .
• cvt_movie2_0022.png .
• cvt_movie2_0023.png .
• cvt_movie2_0024.png .
• cvt_movie2_0025.png .
• cvt_movie2_0026.png .
• cvt_movie2_0027.png .
• cvt_movie2_0028.png .
• cvt_movie2_0029.png .
• cvt_movie2_0030.png .
• cvt_movie2_0031.png .
• cvt_movie2_0032.png .
• cvt_movie2_0033.png .
• cvt_movie2_0034.png .
• cvt_movie2_0035.png .
• cvt_movie2_0036.png .
• cvt_movie2_0037.png .
• cvt_movie2_0038.png .
• cvt_movie2_0039.png .
• cvt_movie2_0040.png .
• cvt_movie2_0041.png .
• cvt_movie2_0042.png .
• cvt_movie2_0043.png .
• cvt_movie2_0044.png .
• cvt_movie2_0045.png .
• cvt_movie2_0046.png .
• cvt_movie2_0047.png .
• cvt_movie2_0048.png .
• cvt_movie2_0049.png .
• cvt_movie2_0050.png .
• cvt_movie2_0051.png .
• cvt_movie2_0052.png .
• cvt_movie2_0053.png .
• cvt_movie2_0054.png .
• cvt_movie2_0055.png .
• cvt_movie2_0056.png .
• cvt_movie2_0057.png .
• cvt_movie2_0058.png .
• cvt_movie2_0059.png .
• cvt_movie2_0060.png .
• cvt_movie2_0061.png .
• cvt_movie2_0062.png .
• cvt_movie2_0063.png .
• cvt_movie2_0064.png .
• cvt_movie2_0065.png .
• cvt_movie2_0066.png .
• cvt_movie2_0067.png .
• cvt_movie2_0068.png .
• cvt_movie2_0069.png .
• cvt_movie2_0070.png .
• cvt_movie2_0071.png .
• cvt_movie2_0072.png .
• cvt_movie2_0073.png .
• cvt_movie2_0074.png .
• cvt_movie2_0075.png .
• cvt_movie2_0076.png .
• cvt_movie2_0077.png .
• cvt_movie2_0078.png .
• cvt_movie2_0079.png .
• cvt_movie2_0080.png .
• cvt_movie2_0081.png .
• cvt_movie2_0082.png .
• cvt_movie2_0083.png .
• cvt_movie2_0084.png .
• cvt_movie2_0085.png .
• cvt_movie2_0086.png .
• cvt_movie2_0087.png .
• cvt_movie2_0088.png .
• cvt_movie2_0089.png .
• cvt_movie2_0090.png .
• cvt_movie2_0091.png .
• cvt_movie2_0092.png .
• cvt_movie2_0093.png .
• cvt_movie2_0094.png .
• cvt_movie2_0095.png .
• cvt_movie2_0096.png .
• cvt_movie2_0097.png .
• cvt_movie2_0098.png .
• cvt_movie2_0099.png .
• cvt_movie2_0100.png .

You can go up one level to the MATLAB source codes.