Diffusion Limited Aggregate Models

Diffusion Limited Aggregate Models

Author: Audrey Karperien, Charles Sturt University (akarpe at sbcglobal.net) and Wayne Rasband

History: 2005/11/14: First version
2006/02/15: makes stacks showing incremental growth, as requested by Tarek Hamida, University of Alberta; adds the option to make binary images

Requires: Java 1.3 or later

Limitations: Very slow with large models

Source: DLA_Generator.java

Installation: Download DLA_Generator.java to the plugins folder, or subfolder, and compile and run it using Plugins/Compile and Run.

Description: This plugin draws diffusion limited aggregate (fractal growth) models in single or multiple steps, as shown below. The plugin has 9 options:

Number of Particles:
The user types in a number for the number of particles that are allowed to attach to the model. The default is 2000. Future releases will include an option to specify the number of points dropped or the number of points allowed to attach.
Particle Size:
Specifies the size in pixels of each particle that is allowed to "diffuse" and stick to the model. The default is 1, and is always corrected to be no less than 1. Currently, particles are always centred on the point to which they stick; future releases will give the option to stick to the edge of a particle.
Image Size:
The user can set a desired image size, but if this is too small for the number of particles selected, the image size is adjusted to accomodate them all.
Particle Shape:
The particle shape can be set to round, triangular, or square.
Square DLA:
Particles are released from either a square or a round outer boundary, as selected by the user.
Fill Particles:
Particles are outlined if this option is left unselected, or filled if it is selected.
Watch Model Grow:
The user can select this option to see growth on the screen, or unselect it to wait until all of the points are calculated. To stop growth, press escape.
Binary Image:
The image can be generated using random colours or black and white.
Stacks:
The user can choose to make stacks or one final image. Typing 1 or less for this option generates single images, and greater than 1 generates stacks that can be scrolled through to see incremental growth. Final images or stacks of diffusion limited growth can be analyzed for the fractal dimension (see FracLac for ImageJ; these are best generated as binary). In addition, diffusion limited growth as a process can be viewed by writing the stack to an avi (see the avi writer plugin, for instance).

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Author:	Audrey Karperien, Charles Sturt University (akarpe at sbcglobal.net) and Wayne Rasband
History:	2005/11/14: First version 2006/02/15: makes stacks showing incremental growth, as requested by Tarek Hamida, University of Alberta; adds the option to make binary images
Requires:	Java 1.3 or later
Limitations:	Very slow with large models
Source:	DLA_Generator.java
Installation:	Download DLA_Generator.java to the plugins folder, or subfolder, and compile and run it using Plugins/Compile and Run.
Description:	This plugin draws diffusion limited aggregate (fractal growth) models in single or multiple steps, as shown below. The plugin has 9 options: Number of Particles: The user types in a number for the number of particles that are allowed to attach to the model. The default is 2000. Future releases will include an option to specify the number of points dropped or the number of points allowed to attach. Particle Size: Specifies the size in pixels of each particle that is allowed to "diffuse" and stick to the model. The default is 1, and is always corrected to be no less than 1. Currently, particles are always centred on the point to which they stick; future releases will give the option to stick to the edge of a particle. Image Size: The user can set a desired image size, but if this is too small for the number of particles selected, the image size is adjusted to accomodate them all. Particle Shape: The particle shape can be set to round, triangular, or square. Square DLA: Particles are released from either a square or a round outer boundary, as selected by the user. Fill Particles: Particles are outlined if this option is left unselected, or filled if it is selected. Watch Model Grow: The user can select this option to see growth on the screen, or unselect it to wait until all of the points are calculated. To stop growth, press escape. Binary Image: The image can be generated using random colours or black and white. Stacks: The user can choose to make stacks or one final image. Typing 1 or less for this option generates single images, and greater than 1 generates stacks that can be scrolled through to see incremental growth. Final images or stacks of diffusion limited growth can be analyzed for the fractal dimension (see FracLac for ImageJ; these are best generated as binary). In addition, diffusion limited growth as a process can be viewed by writing the stack to an avi (see the avi writer plugin, for instance).