A Pinning Actor-Critic Structure-Based Algorithm for Sizing Complex-Shaped Depth Profiles in MFL Inspection with High Degree of Freedom

Algorithm 1

PACS.

(i)	Initialize actor network , critic network , target network and , replay buffer
(ii)	For episode = 1, M do
(iii)	Initialize pinning subdefects , interpolate to have the full depth profile
(iv)	Get initial observation state from reference signal and depth of sub-defects
(v)	For t = 1, T do
(vi)	Generate an action from the output of actor network and exploration noise process
(vii)	Execute action , obtain new depth of pinning sub-defects
(viii)	Interpolate to get the full depth profile within the ROI, calculate reward and new state
(ix)	Store in
(x)	If capacity of replay buffer is full then
(xi)	Randomly sample piece of data from
(xii)	Update the critic network and actor network with (5) and (3)
(xiii)	Update the target networks:
(xiv)
(xv)	end if
(xvi)	If error between each reference subdefect and reconstructed subdefect is less than , then
(xvii)	break
(xviii)	end if
(xix)	end for
(xx)	end for