| 1 | #!/usr/bin/python
|
|---|
| 2 | #
|
|---|
| 3 | # Dominik Neise, Werner Lustermann
|
|---|
| 4 | # TU Dortmund, ETH Zurich
|
|---|
| 5 | #
|
|---|
| 6 | import numpy as np
|
|---|
| 7 | import matplotlib.pyplot as plt
|
|---|
| 8 |
|
|---|
| 9 | class SignalGenerator(object):
|
|---|
| 10 | """ Signal Generator
|
|---|
| 11 | generates signals for testing several helper classes like:
|
|---|
| 12 | * fir filters
|
|---|
| 13 | * signal extractors
|
|---|
| 14 | """
|
|---|
| 15 |
|
|---|
| 16 | def __init__(self, option_str = 'len 100 noise 3', name = 'SignalGenerator'):
|
|---|
| 17 | """ initialize the generator
|
|---|
| 18 | sets default signal to generate
|
|---|
| 19 | """
|
|---|
| 20 | self.option_str = option_str.lower()
|
|---|
| 21 | self.options = make_options_from_str(option_str)
|
|---|
| 22 | self.parse_options()
|
|---|
| 23 | self.name = name
|
|---|
| 24 |
|
|---|
| 25 | def parse_options(self):
|
|---|
| 26 | o = self.options #shortcut
|
|---|
| 27 | if 'len' in o:
|
|---|
| 28 | self.npoints = int(o['len'][0])
|
|---|
| 29 | else:
|
|---|
| 30 | self.npoints = 100
|
|---|
| 31 | if 'noise' in o:
|
|---|
| 32 | self.sigma = float(o['noise'][0])
|
|---|
| 33 | else:
|
|---|
| 34 | self.sigma = 1
|
|---|
| 35 | if 'bsl' in o:
|
|---|
| 36 | self.bsl = float(o['bsl'][0])
|
|---|
| 37 | else:
|
|---|
| 38 | self.bsl = -0.5
|
|---|
| 39 |
|
|---|
| 40 | if 'step' in o:
|
|---|
| 41 | self.step_height = float(o['step'][0])
|
|---|
| 42 | self.step_start = int(o['step'][1])
|
|---|
| 43 | self.step_stop = int(o['step'][2])
|
|---|
| 44 |
|
|---|
| 45 | if 'triangle' in o:
|
|---|
| 46 | self.pulses = []
|
|---|
| 47 | # append 1st pulse to list of pulses
|
|---|
| 48 | self.pulses.append( ( float(o['triangle'][0]) , float(o['triangle'][1]), int(o['triangle'][2]), int(o['triangle'][3]) ) )
|
|---|
| 49 | number_of_pulses_after_1st = (len(o['triangle'])-4)/2
|
|---|
| 50 | for i in range(number_of_pulses_after_1st):
|
|---|
| 51 | self.pulses.append( ( float(o['triangle'][2*i+4]) , float(o['triangle'][2*i+5]), int(o['triangle'][2]), int(o['triangle'][3]) ) )
|
|---|
| 52 |
|
|---|
| 53 | if 'spike' in o:
|
|---|
| 54 | self.spikes = []
|
|---|
| 55 | for i in range(len(o['spike'])/2):
|
|---|
| 56 | self.spikes.append( ( int(o['spike'][2*i]), float(o['spike'][2*i+1]) ) )
|
|---|
| 57 |
|
|---|
| 58 | def __call__(self, option_str = ''):
|
|---|
| 59 | if option_str:
|
|---|
| 60 | self.option_str = option_str.lower()
|
|---|
| 61 | self.options = make_options_from_str(self.option_str)
|
|---|
| 62 | self.parse_options()
|
|---|
| 63 |
|
|---|
| 64 | signal = np.zeros(self.npoints)
|
|---|
| 65 | signal += self.bsl
|
|---|
| 66 | signal += np.random.randn(self.npoints) * self.sigma
|
|---|
| 67 | if 'step' in self.options:
|
|---|
| 68 | signal[self.step_start:self.step_stop] += self.step_height
|
|---|
| 69 | if 'triangle' in self.options:
|
|---|
| 70 | for pulse in self.pulses:
|
|---|
| 71 | pos = pulse[0]
|
|---|
| 72 | height = pulse[1]
|
|---|
| 73 | rise = pulse[2]
|
|---|
| 74 | fall = pulse[3]
|
|---|
| 75 | start = pos - rise
|
|---|
| 76 | stop = pos + fall
|
|---|
| 77 | signal[start:pos] += np.linspace(0., height, rise)
|
|---|
| 78 | signal[pos:stop] += np.linspace(height, 0. , fall)
|
|---|
| 79 | if 'spike' in self.options:
|
|---|
| 80 | for spike in self.spikes:
|
|---|
| 81 | signal[spike[0]] += spike[1]
|
|---|
| 82 | return signal
|
|---|
| 83 |
|
|---|
| 84 | def __str__(self):
|
|---|
| 85 | s = self.name + '\n'
|
|---|
| 86 | s += 'possible options and parameters\n'
|
|---|
| 87 | s += ' * len: number of samples (100)\n'
|
|---|
| 88 | s += ' * noise: sigma (1)\n'
|
|---|
| 89 | s += ' * bsl: level (-0.5)\n'
|
|---|
| 90 | s += ' * step: height, start, end\n'
|
|---|
| 91 | s += ' * triangle: pos height risingedge, fallingedge [pos height ...]\n'
|
|---|
| 92 | s += ' * spike: pos height [pos height ...]\n'
|
|---|
| 93 |
|
|---|
| 94 | s += 'current options are:\n'
|
|---|
| 95 | for key in self.options.keys():
|
|---|
| 96 | s += key + ':' + str(self.options[key]) + '\n'
|
|---|
| 97 | return s
|
|---|
| 98 |
|
|---|
| 99 |
|
|---|
| 100 | # Helper function to parse signalname and create a dictionary
|
|---|
| 101 | # dictionary layout :
|
|---|
| 102 | # key : string
|
|---|
| 103 | # value : [list of parameters]
|
|---|
| 104 | def make_options_from_str(signalname):
|
|---|
| 105 | options = {}
|
|---|
| 106 | for word in (signalname.lower()).split():
|
|---|
| 107 | if word.isalpha():
|
|---|
| 108 | current_key = word
|
|---|
| 109 | options[current_key] = []
|
|---|
| 110 | # if word.isdigit():
|
|---|
| 111 | else:
|
|---|
| 112 | options[current_key].append(word)
|
|---|
| 113 | # else:
|
|---|
| 114 | # print '-nothing'
|
|---|
| 115 | return options
|
|---|
| 116 |
|
|---|
| 117 | def plotter(signal, text):
|
|---|
| 118 | x=range(len(signal))
|
|---|
| 119 | ax = plt.plot(x, signal, 'b.', label='signal')
|
|---|
| 120 | plt.title('test of SignalGenerator with option string:\n' + text)
|
|---|
| 121 | plt.xlabel('sample')
|
|---|
| 122 | plt.legend()
|
|---|
| 123 | plt.grid(True)
|
|---|
| 124 | plt.show()
|
|---|
| 125 |
|
|---|
| 126 | if __name__ == '__main__':
|
|---|
| 127 | """ test the class """
|
|---|
| 128 | myGenerator = SignalGenerator('len 400 noise 0.3 bsl -2.5 triangle 50 10.2 10 100 65 10 150 20 180 10 250 10 spike 100 50. 20 50 21 49')
|
|---|
| 129 | sig = myGenerator()
|
|---|
| 130 | print myGenerator
|
|---|
| 131 | plotter(sig, myGenerator.option_str) |
|---|
