first try

phase-encoding-simple.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+# -*- coding: UTF-8 -*-
+from scipy.optimize import differential_evolution
+import numpy as np
+voxel_num = 5
+phase_range = np.pi
+phase_init = 0.0
+
+total_periods = 50
+rf_samples_per_period = 10
+
+voxel_amplitudes = np.random.rand(voxel_num)
+test_amplitudes = np.zeros(voxel_num)
+test_amplitudes = voxel_amplitudes
+voxel_phases = np.linspace(0,phase_range, voxel_num)
+if len(voxel_amplitudes) != len(voxel_phases):
+    print("ERROR! Size of amplitude and phase arrays do not match!")
+    raise
+
+omega = 2*np.pi
+period = 2*np.pi/omega
+time_steps = np.linspace(0, period*total_periods, rf_samples_per_period*total_periods)
+
+def rf_signal(time):
+    signal = 0.0
+    for i in range(voxel_num):
+        signal += voxel_amplitudes[i]*np.sin(
+            omega*time + voxel_phases[i] + phase_init
+            )
+    return signal
+
+def assumed_signal(time, amplitudes):
+    signal = 0.0
+    for i in range(voxel_num):
+        signal += amplitudes[i]*np.sin(
+            omega*time + voxel_phases[i] + phase_init
+            )
+    return signal
+
+def fitness(amplitudes):
+    diff = rf_signal(time_steps) - assumed_signal(time_steps, amplitudes)
+    return np.sqrt(np.mean(np.square(diff)))
+
+#print(voxel_phases)
+print (voxel_amplitudes)
+# import matplotlib.pyplot as plt
+# plt.plot(time_steps, rf_signal(time_steps))
+# plt.show()
+#print(fitness(test_amplitudes))
+
+bounds = []
+minmax = (0,1)
+for i in range(voxel_num):
+    bounds.append(minmax)
+result = differential_evolution(fitness, bounds, polish=True)
+print(result.x, result.fun)
+print("Diff")
+print((voxel_amplitudes-result.x))
+print("percent")
+print((voxel_amplitudes-result.x)*100)