## 3 Results and Discussion  
### Comparison Between OCT and bOCT Images  
Figure 4a-f show the OCT images obtained for a male subject, with the vertical axis representing the depth and the horizontal axis representing the lateral direction. Here, Figure 4a-c show the images obtained for a male subject aged 20 or above, while Figure 4d-f show the images obtained for a male subject aged 30 or older. Image pairs (a) and (d), (b) and (e), and (c) and (f) are, respectively, those obtained before heating, immediately after heating, and five minutes after finishing heating. The bright areas correspond to higher reflectivity, while the dark regions correspond to regions with lower reflectivity. For both age groups, the laminar organization of the skin can be seen. Moreover, for the group of participants in their 20s, the laminar organization of the skin can be observed along with the blood vessels in the dermis layer under all three conditions. On the other hand, for the 30 and over age group, the laminar organization can be distinguished; however, it can be seen that the blood vessels are barely distinguishable. Moreover, in both age groups, it can be concluded that when changing the environment, it is difficult to distinguish the structural differences from the OCT images themselves. From the OCT images shown in Figure 4, the bOCT images were calculated using Equation (2), and the calculated results are shown in Figure 5.  
Figure 5a-c show bOCT images obtained from a male subject in his 20s, while Figure 5d-f show bOCT images obtained from a male subject in his 30s or older. Image pairs (a) and (d), (b) and (e), and (c) and (f) are, respectively, those obtained before heating, immediately after heating, and five minutes after finishing heating. In all of the bOCT images obtained for both age groups (20s and 30s), red regions indicate stronger temporal variability, while blue regions indicate weaker temporal variability. For a male in their 20s, comparing the images before heating (a) and five minutes after heating (c), a large difference can be seen both in the surface and in the deeper regions. On the other hand, between (a) and (b), i.e., before and immediately after heating, some variation near the surface can be seen in comparison to the deeper region. In contrast, for a male in his 30s or over, comparing the image before heating (d) with the images immediately after (e) and five minutes after heating (f), a considerable change can be seen both near the surface and in  
the deeper regions. However, close to the surface, there is almost no observable difference between immediately after heating (e) and five minutes after heating (f), although a fairly small difference can be seen in the deeper regions between these two images. Similarly, Figure 6a-c were obtained from a female subject in her 20s, while Figure 6d-f were obtained from a female subject in her 30s or older. Image pairs (a) and (d), (b) and (e), and (c) and (f) are, respectively, those obtained before heating, immediately after heating, and five minutes after finishing heating. In the bOCT images obtained for both age groups (20s and 30s), the red regions show stronger temporal variability, while the blue regions show weaker temporal variability. For the female in her 20s, comparing (a) and (b), i.e., before and immediately after heating, increased variability can be seen closer to the surface in comparison to the deeper regions. On the other hand, before heating (a) and five minutes after heating (c), the temporal variability decreased near the surface and increased in the deeper region. In contrast, for the female aged 30 or older, comparing the image before heating (d) with the image immediately after heating (e), there is a large decrease in the  
Figure 4: OCT structural images obtained from male subjects aged in their 20s (**above**) and in their 30s (**below**) under different conditions: before heating (**a,d**), immediately after heating (**b,e**), and after 5 min of rest following heating (**c,f**).