基于逻辑的方法是用来监控所有 所观察到的行为的逻辑一致 解释，因此必须考虑所有可能的和一致的计划或目标。Kautz设计了一个正式的规划识别理论。他描述了规划识别的过程，逻辑过程的界限。所有的行动和计划被统称为目标，和识别的知识是由一组一阶语句调用的事件层次结构在一阶逻辑编码来表示，它定义了抽象、分解和事件类型之间的功能关系。
Logic-based approaches are used to monitor all the logically consistent explanations of the observed actions, thus making it compulsory to consider all possible and consistent plans or goals. Kautz devised a formal theory of plan recognition. He described the process of plan recognition as a logical process of circumscription. All actions performed and plans drawn are uniformly referred to as goals, and a recognizer’s knowledge is represented by a set of first-order statements called event hierarchy encoded in first-order logic, which defines abstraction, decomposition and functional relationships between types of events.
Kautz’s proposed an algorithm for plan recognition which has an exponential time complexity in worst case, and is measured in the size of input hierarchy. Lesh and Etzioni advanced further in this process of plan recognition and devised methods in scaling up goal recognition to scale up his work computationally. Apart from the Kautz’s approach where the plan library is explicitly represented, Lesh and Etzioni’s approach allows automatic plan-library construction from domain primitives. They introduced compact representations and efficient algorithms for goal recognition on large plan libraries.
Inconsistent plans and goals are repeatedly observed and implemented when new actions arrive. Besides, they also provide methods for adapting a goal recognizer to handle individual idiosyncratic behaviour given a sample of an individual’s recent behaviour. The main problem of logic-based approach is that it is unable and not feasible to represent uncertainty. There is no mechanism for preferring one consistent approach to another and incapable of deciding whether one particular plan is more likely than another, as long as both of them can be consistent enough to explain the actions observed. There is also a lack of learning ability associated with logic based methods.
Another approach to this logical activity is to model a stream of images and then organizing it to evaluate the current situation and observe the supplied input to form the desired output. This type of process can be used in fields like medical, sports, etc.