This section presents a series of figures and extended legends that illustrate the principle data structures used represent connected edge strings and stereo matches. These are the data structures that result from canny edge processing and linking and are used by the current stereo algorithm. They could also result from other edge processes and edge based stereo algorithms.
Other data structures may exist transiently in the processing stages that compute linked edges and locate stereo matches. There existence however can not be assumed outside the particular processing stage.
Even these approved data structures may not exist by default. But once in existence they can be utilised by other processing modules than the one used to create them.
In the light of experience and to allow the system to be flexible to the requirements of the user, the basic representation of Tina primitives has been kept as simple and uniform as possible. Extendibility and generality is achieved by using a property list for the storage of additional information specific to each different application. The property lists field is always defined in other Tina structures as
struct list *props;
Property lists are used throughout the Tina system (they are described in the chapter of the programmers guide on list processing).
Extra information that describes the relationships between primitives (such as edge strings or order along the image rasters) is kept outside the primitives themselves. This approach further enhances the modularity of the representations though at the cost of an increas in complexity. The most important forms of generic data structure used to combine data throughout the Tina system are lists, doubly directed lists, and strings (see the programmers guide).