Algorithm 1 Multi-focus image fusion algorithm.

1: Input $I_N$: Source images from fluorescence microscopies.

2: Output $F$, All-in-focus image.

3://Obtain guided filtered focus map of source images

4://Obtain output $F$ by selecting the pixels $\left(i,j\right)$ from the set of source images, which depends on the calculated weight of the guidance image $I_{gni}$ for the respective pixels.

5: for $i=1: p$

6:    for $j=1:q$

7:      $I_{arm}\left(k\right)=argsort\left(I_{gni}\left(i,j\right)\right)$

8:    //Arrange the calculated weights of the guidance image with respect to the source images.

9:        for $k=1:N/$/where $N$ is the number of source images to be fused

10:          $F\left(i,j\right)+=I_{arm}\left(k\right)·I_k\left(i,j\right)$

11:      //Obtain output $F$ by sequentially multiplying the source with the maximum weight.

12:        end for

13:    end for

14:  end for