Patent ID: 7362806

Claim:
An object activity recognition method comprising the steps of: (a) obtaining feature vectors by motion estimation for video frames; (b) determining a state, to which each frame belongs, using the obtained feature vectors; and (c) determining an activity model, which maximizes the probability between activity models and a video frame provided from a given activity model dictionary using a transition matrix for the determined state, as the recognized activity, wherein the step (c) comprises a step of finding an activity model, which maximizes probability P(O|λ) from the given activity model dictionary {λ 1 , λ 2 , . . . , λ E }, when T is a positive integer indicating the number of frames forming the video sequence, Z 1 , 2 , . . . , Z T are feature vectors of first frame, second frame, . . . , T-th frame, respectively, and if video frame O={Z 1 , 2 , . . . ,Z T } is given and E is the number of state models, and wherein the transition matrix is obtained by using an expectation-maximization (EM) algorithm based on the observation symbol probability {b j (.)} corresponding to scene j in the training process.