## 3 Results
In Figure 6, an image reconstructed using the correction is compared with that using a conventional approach. We can see that the image from the conventional approach, shown in Figure 6a, has severe residual interference fringes even after the image reconstruction. However, in the corrected image, shown in Figure 6b, the residual fringes are removed almost completely, indicating that the proposed method is highly effective in the enhancement of a pre-reconstructed FF-OCT en face image. Figure 4: The correction factor \(\Gamma\), extracted from the intermediate images of Figure 3, calculated using Equation (13), by taking the area averages with a different window size. The result varies rapidly at the beginning, but smoothly converges to 1.51 as the window size increases. Figure 5: The intermediate images of Figure 3, but re-calculated with the correction factor of \(\Gamma\) = 1.51. The brightness levels of the re-calculated images in (**a**,**b**) become similar to each other after the correction. White scale bars: 200 μm. To confirm the usefulness of the proposed method for a post-modulation parameter adjustment, the method was applied not only to a single en face image but also to a three-dimensional (3-D) volume image, composed with a stack of 50 en face images taken at different depths. With the same Philippine coin, a series of interferograms, such as those shown in Figure 2, were first captured at over a 50 \(\upmu\)m depth with 1 \(\upmu\)m steps, and the corresponding en face images were reconstructed using the conventional method. From a single en face image of the 3-D image, showing the bottom of the coin surface, the correction factor \(\Gamma\) was calculated. Because we had already tested the convergence of \(\Gamma\) in Figure 4, we used the converged value of \(\Gamma\), i.e., 1.51. Every en face image of the original 3-D volume image was corrected using the same correction factor \(\Gamma\) and the corrected 3-D image was compared with the original image shown in Figure 7.  
Figure 6: The FF-OCT en face images, reconstructed without (**a**) and with (**b**) the proposed post-processing method. With a closer look, we can see residual fringes in (**a**), especially between the letters A and L. The residual fringes in (**a**) were almost removed in (**b**). White scale bars: 200 \(\upmu\)m.  
Figure 3.0 A three-dimensional FF-OCT image (top view) of the Philippine coin, reconstructed using a conventional method (**a**) and corrected with the proposed post-processing method (**b**). The enlarged images (**c**,**d**), corresponding to the red boxes in (**a**,**b**), respectively, show that the residual fringes are well-removed with the proposed method. White scale bars: 200 \(\upmu\)m.  
Figure 7a shows the 3-D FF-OCT image (top view) of the coin, reconstructed without applying the proposed post-processing method. As the motivation for our research, we can see some residual fringes, particularly at the red box in Figure 7a. These residual fringes removed almost completely with the proposed method as shown in Figure 7b. We can clarify this enhancement with the images in Figure 7c,d, which are enlarged images of the red boxes in Figure 7a,b, respectively. It is interesting to note that some scratches on the bottom surface of the coin, which were difficult to distinguish due to the residual fringes, became sharply visible after the correction.