In MeVisLab, programming image processing algorithms or interactive image/3D scene manipulation is primarily done by establishing networks consisting of modules and connections between them. Modules encapsulate specific algorithms written in C++ and provide an interface in MeVisLab through fields. These fields can represent simple data, such as numbers or strings, but can also handle more complex data, such as six-dimensional voxel images. Fields of modules of the same type can be connected to form networks that represent algorithms on a higher abstraction layer.

In the following figure, a typical assembly of connected modules in a network, their panels, and viewers can be seen.

Figure 3.1. Example Network for SynchroView2D with Viewer (Panel), Automatic Panel, and Settings

The following information can be found in this chapter:

For module and network shortcuts, see Section 4.3.10, “Preferences — Shortcuts”.

3.1. Types of Modules

There are three types of modules:

Table 3.1. Module Types

Type	Color	Look	Characteristics
ML module	Blue		Page-based and demand-driven processing of voxels
Open Inventor module	Green		Visual scene graphs (3D)
Macro module	Brown		Combination of other module types, allowing implementing hierarchies and scripted interaction

If a module is invalid, it is displayed in bright red.

The number of warning and error messages printed to the debug console is displayed in the upper right corner of the module. Once the debug console is cleared, the warning and error indicators at the module are also cleared. If the module produces information messages, their number is printed in gray at this position. This enables a network or module developer to find the modules in a network that produce messages quickly.

Table 3.2. Invalid Modules

Module Appearance	Explanation
	Invalid module
	Macro containing at least one invalid module within its internal network, which could be either a regular module or another macro module

For information and examples on how to construct networks from modules, please refer to the Getting Started in which image processing pipelines, scene graphs, and macro module creation are discussed in detail.