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Materials Science in Additive Manufacturing                             Super-resolution method for L-PBF





































            Figure 4. The residual channel with the efficient channel attention network branch


              Where  I  R   12424   is the input LR image (Y channel),   can achieve high-performance and low-complexity CA
                     LR
            output  R 64 24 24  is the output features of the RCEN,   weight allocation. It exhibits better  performance  than


                 1
            Conv   represents the CNN layer of 3×3 kernel,   attention mechanisms such as Convolutional Block

                33
                                                               Attention Module (CBAM)  and Squeeze-and-Excitation
                                                                                     41
            RG   represents the total of N RG connected in series.  Networks (SENet).  ECA-Net implements a local cross-

                                                                              42
               N
              Each RG module can be described as:              channel interaction strategy without dimensionality
                                                               reduction and an adaptive method for determining coverage
            Out RG   X RG   Conv  RCEB  X        (IV)    of local cross-channel interaction. By introducing it into the
                                    M
                                        RG
                            33

                                                               RCEB network, the network can focus more on the high-
              Where, X  and Out  are inputs and outputs of the RG,   frequency information of the melt pool based on the melting
                              RG
                      RG
            respectively, and RCEB  (•) represents the total of M RCEB   features in the current LR image, thereby improving the
                              M
            connected in series.                               network performance. The ECA-Net is shown in Figure 4
                                                               and can be described by the following equations: 39
              Each RCEB module can be described as:                           1   H  W  xi j

                              (
                                                                         c
                                                                c

            Out RCEB =  X RCEB  ECA Conv 33× +  ( Relu (Conv 33×  ( X RCEB ))))  z  GAP x     HW i1   c  ,  (VI)
                                                                                     j1
                                                                     C Dz
                                                       (V)     s   1  k  c                             (VII)

                                                                c
              Where X RCEB  and Out RCEB  are inputs and outputs of the
                                                                ∼
            RCEB, respectively, Relu (•) is the activation function, and   X = s xi  c                  (VIII)
                                                                 c
                                                                    c
            ECA (•) represents the ECA-Net according to Equations   Where H, W, and C represent the length, width, and
            VI–VIII.
                                                               number of channels of the input feature map, respectively;
              The attention mechanism is common in SR networks,   x  represents the c-th channel of the feature map; GAP (•)
                                                                c
            which invest more network resources into the ROI through   represents the global average pooling; C1D  (•) represents
                                                                                                 K
            fast computation. The channel attention (CA) was used in   the 1-D Conv layer and k is its kernel size which is 3 in this
                                                                                                           
            RCAN.  However,  it only  considers  the  interdependence   study;  σ  (•)  represents  the  sigmoid  function;  and  X
                                                                                                            c
            between feature channels to allocate channel weights.   represents the final output of the ECA-Net. To prevent the
            Therefore, the ECA-Net was used to replace it. ECA-Net    network  from  being  inundated  by a  large  amount of
                                                         39
            Volume 3 Issue 4 (2024)                         6                              doi: 10.36922/msam.5585
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