Direct inverse reinforcement learning with density ratio estimation

    公开(公告)号:US10896383B2

    公开(公告)日:2021-01-19

    申请号:US15425924

    申请日:2017-02-06

    Abstract: A method of inverse reinforcement learning for estimating reward and value functions of behaviors of a subject includes: acquiring data representing changes in state variables that define the behaviors of the subject; applying a modified Bellman equation given by Eq. (1) to the acquired data: r ⁡ ( x ) + γ ⁢ ⁢ V ⁡ ( y ) - V ⁡ ( x ) = ⁢ ln ⁢ ⁢ π ⁡ ( y | x ) b ⁡ ( y | x ) , ⁢ ( 1 ) = ⁢ ln ⁢ ⁢ π ⁡ ( x , y ) b ⁡ ( x , y ) - ln ⁢ ⁢ π ⁡ ( x ) b ⁡ ( x ) ,                                                ⁢ ( 2 ) where r(x) and V(x) denote a reward function and a value function, respectively, at state x, and γ represents a discount factor, and b(y|x) and π(y|x) denote state transition probabilities before and after learning, respectively; estimating a logarithm of the density ratio π(x)/b(x) in Eq. (2); estimating r(x) and V(x) in Eq. (2) from the result of estimating a log of the density ratio π(x,y)/b(x,y); and outputting the estimated r(x) and V(x).

    2D discrete fourier transform with simultaneous edge artifact removal for real-time applications

    公开(公告)号:US10121233B2

    公开(公告)日:2018-11-06

    申请号:US15746407

    申请日:2016-07-20

    Abstract: A method for performing 2-dimensional discrete Fourier transform of a subject image data to be performed in one or more digital processors includes performing 1-dimensional fast Fourier transform on each row of the subject image data and 1-dimensional fast Fourier transform on each column of the subject image, and performing a simplified fast Fourier transform processing on the extracted boundary image without performing column-by-column 1-dimensional fast Fourier transform by: performing 1-dimensional fast Fourier transform only on a first column vector in the extracted boundary image data, using scaled column vectors to derive fast Fourier transform of remaining columns of the extracted boundary image data, and performing 1-dimensional fast Fourier transform on each row of the extracted boundary image data. Then, fast Fourier transform of a periodic component of the subject image data with edge-artifacts removed and fast Fourier transform of a smooth component of the subject image data are derived from results of steps (b) and (c).

Patent Agency Ranking