翻译成英语：利用公式9和公式10求解fxy的形式。从理论上分析StO2对反射光强度的影响和组织膨胀程度对反射光强度的影响应当是彼此独立互不相关的在fxy公式中应当反映为线性叠加。从图2a和图2c中各条曲线几乎没有出现相交的情况也可以证明StO2和组织膨胀程度对预测值的影响是线性组合。按照公式11拟合生成的三维函数拟合图如图2c所示。

Translate to English: Use formulas (9) and (10) to solve for the form of f(x,y). Theoretical analysis suggests that the influence of StO2 on reflected light intensity and the influence of tissue expansion on reflected light intensity should be independent and unrelated to each other, and should be reflected as a linear superposition in the f(x,y) formula. From the curves in Figure 2(a) and Figure 2(c), it can be observed that there is almost no intersection, which also proves that the effects of StO2 and tissue expansion on the predicted values are a linear combination. The three-dimensional function fitted according to formula (11) is shown in Figure 2(c)