Hierarchical Classifier - Similar Models

Similar Models

One similar model is the notion of graphical models where an input space is systematically broken down into subspaces, and those into smaller subspaces, and so on, creating a hierarchy of input spaces. This allows for predictions about behavior of inputs in various regions with statistical methods such as Bayesian networks allowing for easily computable conditional probabilities. Recently, there has been a lot of research in this area with respect to vision systems. Hierarchical classifiers are extremely similar to these models, but do not have to depend on statistical interpretation.

Another similar model is the simple neural network. Commonly, neural networks are a network of individual nodes that each tries to learn a function of input to output. The functionality of the network as a whole is dependent on the ability of the nodes to work together to yield the correct overall output. Neural networks can be trained to do lots of tasks and are often domain-specific. However, as in the case of graphical models, neural networks have shown great general-purpose behavior in computer vision even when tackling relatively general problems. Hierarchical classifiers can, in fact, be seen as a special case of neural networks where, instead of learning functions, discrete output classes are learned. Learning is then a pattern-match with an error threshold instead of an interpolation of an approximate function.

Neuroscience's perspective on the workings of the human cortex also serves as a similar model. The generally accepted view of the brain today is that the brain is a generic pattern machine that works to abstract information again and again until it relates to a broad stored concept. For instance, a familiar face is not stored as a collection of pixels, rather as a combination of very specific eyes, nose, mouth, ears, etc. In this way, when the data has been classified into those components, that collection of those components can then be classified into that face. Thus, neuroscience trends and data are very valuable to research in these areas as they are highly relevant to the inner workings of these models. This is especially true since the human brain is inherently very good at applications like facial recognition that these models strive to be good at. The brain is in a sense a benchmark of proficiency for hierarchical processing.

Read more about this topic:  Hierarchical Classifier

Famous quotes containing the words similar and/or models:

    We do not need to minimize the poverty of the ghetto or the suffering inflicted by whites on blacks in order to see that the increasingly dangerous and unpredictable conditions of middle- class life have given rise to similar strategies for survival. Indeed the attraction of black culture for disaffected whites suggests that black culture now speaks to a general condition.
    Christopher Lasch (b. 1932)

    Friends broaden our horizons. They serve as new models with whom we can identify. They allow us to be ourselves—and accept us that way. They enhance our self-esteem because they think we’re okay, because we matter to them. And because they matter to us—for various reasons, at various levels of intensity—they enrich the quality of our emotional life.
    Judith Viorst (20th century)