增加模块；增加主调用命令

prosail_method/modules/campbell.py

@@ -0,0 +1,53 @@
+import numpy as np
+
+def campbell(ala):
+    """
+    Campbell's leaf angle distribution function (ellipsoidal).
+    
+    Parameters:
+        ala : average leaf angle in degrees
+
+    Returns:
+        freq : relative frequency for 13 inclination bins
+        litab: bin centers (degrees)
+    """
+    tx1 = np.array([10., 20., 30., 40., 50., 60., 70., 80., 82., 84., 86., 88., 90.])
+    tx2 = np.array([0., 10., 20., 30., 40., 50., 60., 70., 80., 82., 84., 86., 88.])
+    litab = (tx1 + tx2) / 2
+    n = len(litab)
+
+    tl1 = np.radians(tx1)
+    tl2 = np.radians(tx2)
+
+    excent = np.exp(-1.6184e-5 * ala**3 + 2.1145e-3 * ala**2 - 0.12390 * ala + 3.2491)
+
+    freq = np.zeros(n)
+    for i in range(n):
+        x1 = excent / np.sqrt(1 + (excent**2) * np.tan(tl1[i])**2)
+        x2 = excent / np.sqrt(1 + (excent**2) * np.tan(tl2[i])**2)
+
+        if excent == 1:
+            freq[i] = abs(np.cos(tl1[i]) - np.cos(tl2[i]))
+        else:
+            alpha = excent / np.sqrt(abs(1 - excent**2))
+            alpha2 = alpha**2
+            x1_sq = x1**2
+            x2_sq = x2**2
+
+            if excent > 1:
+                alpx1 = np.sqrt(alpha2 + x1_sq)
+                alpx2 = np.sqrt(alpha2 + x2_sq)
+                dum1 = x1 * alpx1 + alpha2 * np.log(x1 + alpx1)
+                dum2 = x2 * alpx2 + alpha2 * np.log(x2 + alpx2)
+                freq[i] = abs(dum1 - dum2)
+            else:
+                almx1 = np.sqrt(alpha2 - x1_sq)
+                almx2 = np.sqrt(alpha2 - x2_sq)
+                dum1 = x1 * almx1 + alpha2 * np.arcsin(x1 / alpha)
+                dum2 = x2 * almx2 + alpha2 * np.arcsin(x2 / alpha)
+                freq[i] = abs(dum1 - dum2)
+
+    freq_sum = np.sum(freq)
+    freq_normalized = freq / freq_sum if freq_sum != 0 else freq
+
+    return freq_normalized, litab