# Quantitative Study of the Maceral Groups of Laminae Based on Support Vector Machine
## 4 Results and Discussion
### Image Classification Result and Statistical Analysis  
Figure 6 shows the image classification result and the area percentage of each category in each lamina. The classification results can solve the challenge of quantifying macroals. Importantly, this addresses the problem that microscopic observers cannot accurately describe macroals in source rocks to other geologists.  
Since mineral matter is not a macroal group and the AOM quantification criteria are controversial [40], we excluded them from the subsequent analysis. From Figure 6, it is clear that the concentrations of mineral matter and AOM are the highest. The concentrations of pyrite, alginite, sporinite, vitrinite, and inertinite in the lamina account for 1.80%, 0.39%, 0.36%, 0.59%, and 0.78% respectively (Figure 7a). However, there is a large variation in their contents in different laminae due to paleoenvironment changes [41; 42]. To explore the distribution, we divided the lamina into four parts according to the differences in the brightness values [43], i.e., we labeled clayey laminae as dark laminae (dk1 and dk2), and silty laminae as bright laminae (b1 and b2).  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Categories** & **Pyrite** & **AOM** & **MM** & **Alginite** & **Sporinite** & **Vitrinite** & **Inertinite** \\ \hline Pyrite & 45 & 0 & 4 & 0 & 0 & 0 & 1 \\ AOM & 0 & 47 & 1 & 0 & 1 & 1 & 0 \\ MM & 1 & 0 & 49 & 0 & 0 & 0 & 0 \\ Alginite & 0 & 2 & 5 & 43 & 0 & 0 & 0 \\ Sporinite & 0 & 13 & 1 & 1 & 35 & 0 & 0 \\ Vitrinite & 0 & 0 & 5 & 0 & 0 & 40 & 5 \\ Inertinite & 13 & 0 & 5 & 0 & 0 & 1 & 31 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Confusion matrix for classification result.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Evaluation Metrics** & **Pyrite** & **AOM** & **MM** & **Alginite** & **Sporinite** & **Vitrinite** & **Inertinite** & **Overall** \\ \hline Precision & 76.27\% & 75.81\% & 70.00\% & 97.73\% & 97.22\% & 95.24\% & 83.78\% & 85.15\% \\ Recall & 90.00\% & 94.00\% & 98.00\% & 86.00\% & 70.00\% & 80.00\% & 62.00\% & 82.86\% \\ F1 & 82.57\% & 83.93\% & 81.67\% & 91.49\% & 81.39\% & 86.96\% & 71.26\% & 82.75\% \\ Overall accuracy & \multicolumn{3}{c}{82.86\%} & Kappa, K & \multicolumn{3}{c}{0.80} \\ \hline \hline \end{tabular}
\end{table}
Table 2: Accuracy evaluation of the classification result.  
In the b1 and b2 laminae (Figure 7b,d), the proportions of pyrite account for the largest area because of the extensive distribution of framboidal pyrites and the discovery of biogenic (pyrite-filled) remains in bright laminae. In the dk1 and dk2 (Figure 7c,e), vitrinite and sporinite cover the largest percentage of area. Overall, the alginite and inertinite are more equally distributed.  
There are significant differences in the area ratio of the thin laminae. To further analyze the classification distribution of the results, we divided them into 30 thin laminae by pixels (Figure 6). Pyrite occupies the highest proportion in the 16 th thin lamina, accounting for 3.68%, followed by 3 rd and 2 nd. Alginite has the highest distribution in the 28 th thin lamina, namely 1.33%, followed by 2 nd and 26 th, with a notable variation between the 25 th and 29 th thin laminae. Sporinite occupies the highest proportion in the 24 th thin  
Figure 6: Image classification result and the area percentage content of each classification.  
Figure 7: The area statistical analysis of image classification result. (**a**) Overall area proportion; (**b**) area proportion of b1; (**c**) area proportion of dk1; (**d**) area proportion of b2; and (**e**) area proportion of dk2.  
lamina, accounting for 1.07%, followed by 20 th and 23 rd. Vitrinite concentrates in the 29 th, 7 th, and 20 th thin laminae, with the highest value being 3.86% in the 29 th thin lamina. Inertinite focuses on the 4 th, 29 th, and 19 th thin laminae, with the highest value being 2.11% in the 4 th thin lamina. With this method, even tiny differences in the thin laminae can be expressed.