Simple Pulse finding using Template Correlation

This commit is contained in:
Eric Teunis de Boone 2023-04-19 17:01:04 +02:00
parent 465b78c535
commit 04858ea01a

View file

@ -10,16 +10,40 @@ rng = np.random.default_rng()
class Waveform:
name = None
time = None
signal = None
dt = None
def __init__(signal, time=None, name=None, dt=None):
_t = None
def __init__(self,signal=None, dt=None, t=None, name=None):
self.signal = signal
self.time = time
self.name = name
if self.time is None and dt is not None:
self.time = dt * len(signal)
if t is not None:
assert len(t) == len(signal)
self._t = t
self.dt = t[1] - t[0]
elif dt is not None:
self.dt = dt
# Lazy evaluation of time
@property
def t(self):
if self._t is None:
return self.dt * np.arange(0, len(self.signal))
return self._t
@t.setter
def t(self, value):
self._t = value
@t.deleter
def t(self):
del self._t
def __len__():
return len(self.signal)
def white_noise_realisation(N_samples, noise_sigma=1, rng=rng):
return rng.normal(0, noise_sigma or 0, size=N_samples)
@ -56,7 +80,7 @@ def my_correlation(in1, template):
return corrs, (in1_long, template_long, lags)
def trace_upsampler(template_signal, trace, template_t, trace_t):
template_dt = template_t[1] - template_t[0]
template_dt = template.t[1] - template.t[0]
trace_dt = trace_t[1] - trace_t[0]
upsample_factor = trace_dt/template_dt
@ -89,56 +113,81 @@ if __name__ == "__main__":
template_length = 100 # ns
noise_sigma_factor = 1e1 # keep between 10 and 0.1
N_residuals = 50*3
antenna_dt = 2 # ns
antenna_timelength = 2048 # ns
_deltapeak = util.deltapeak(timelength=template_length, samplerate=1/template_dt, offset=10/template_dt)
template_t = util.sampled_time(1/template_dt, start=0, end=template_length)
template_signal = antenna_bp(_deltapeak[0], *bp_freq, (np.sqrt(antenna_dt/template_dt))*template_dt) # TODO: fix sqrt constant
template_peak_time = template_t[_deltapeak[1]]
#
# Create the template
#
template = Waveform(None, dt=template_dt, name='Template')
_deltapeak = util.deltapeak(timelength=template_length, samplerate=1/template.dt, offset=10/template.dt)
template.signal = antenna_bp(_deltapeak[0], *bp_freq, (np.sqrt(antenna_dt/template_dt))*template_dt) # TODO: fix sqrt constant
template.peak_sample = _deltapeak[1]
template.peak_time = template.dt * template.peak_sample
if False: # show template
if True: # show template
fig, ax = plt.subplots()
ax.set_title("Deltapeak and Bandpassed Template")
ax.set_xlabel("Time [ns]")
ax.set_ylabel("Amplitude")
ax.plot(template_t, max(template_signal)*_deltapeak[0])
ax.plot(template_t, template_signal)
ax.plot(template.t, max(template.signal)*_deltapeak[0])
ax.plot(template.t, template.signal)
fig.savefig('figures/11_template_deltapeak.pdf')
if True:
plt.close(fig)
#
# Find difference between true and templated times
#
time_residuals = np.zeros(N_residuals)
for j in range(N_residuals):
do_plots = j==0
# receive at antenna
antenna_t = util.sampled_time(1/antenna_dt, start=0, end=antenna_timelength)
antenna_samplelength = len(antenna_t)
## place the deltapeak signal at a random location
antenna_true_signal, antenna_peak_location = util.deltapeak(timelength=antenna_timelength, samplerate=1/antenna_dt, offset=[0.2, 0.8], rng=rng)
antenna_peak_time = antenna_t[antenna_peak_location]
antenna = Waveform(None, dt=antenna_dt, name='Signal')
antenna_true_signal, antenna_peak_sample = util.deltapeak(timelength=antenna_timelength, samplerate=1/antenna.dt, offset=[0.2, 0.8], rng=rng)
antenna.signal = antenna_true_signal
antenna.peak_sample = antenna_peak_sample
antenna.peak_time = antenna.dt * antenna.peak_sample
if not True: # flip polarisation
antenna_true_signal *= -1
if do_plots:
print(f"Antenna Peak Time: {antenna.peak_time}")
print(f"Antenna Peak Sample: {antenna.peak_sample}")
if False: # bandpass when emitting the signal
antenna.signal = antenna_bp(antenna.signal, *bp_freq, antenna.dt)
if False: # flip polarisation
antenna.signal *= -1
## Add noise
noise_amplitude = max(template_signal) * noise_sigma_factor
noise_realisation = noise_amplitude * white_noise_realisation(len(antenna_true_signal))
antenna_unfiltered_signal = antenna_true_signal + noise_realisation
antenna_signal = antenna_bp(antenna_unfiltered_signal, *bp_freq, antenna_dt)
noise_amplitude = max(template.signal) * noise_sigma_factor
noise_realisation = noise_amplitude * white_noise_realisation(len(antenna.signal))
true_time_offset = antenna_peak_time - template_peak_time
antenna_unfiltered_signal = antenna.signal + noise_realisation
antenna.signal = antenna_bp(antenna_unfiltered_signal, *bp_freq, antenna.dt)
if True: # show signals
true_time_offset = antenna.peak_time - template.peak_time
if do_plots: # show signals
fig, axs = plt.subplots(2, sharex=True)
axs[0].set_title("Antenna Waveform")
axs[-1].set_xlabel("Time [ns]")
axs[0].set_ylabel("Amplitude")
axs[0].plot(antenna_t, antenna_signal, label='bandpassed w/ noise')
axs[0].plot(antenna_t, antenna_unfiltered_signal, label='true signal w/ noise')
axs[0].plot(antenna_t, antenna_true_signal, label='true signal w/o noise')
axs[0].plot(antenna.t, antenna.signal, label='bandpassed w/ noise', alpha=0.9)
axs[0].plot(antenna.t, antenna_unfiltered_signal, label='true signal w/ noise', alpha=0.9)
axs[0].plot(antenna.t, antenna_true_signal, label='true signal w/o noise', alpha=0.9)
axs[0].legend()
axs[1].set_title("Template")
axs[1].set_ylabel("Amplitude")
axs[1].plot(template_t, template_signal, label='orig')
axs[1].plot(template_t + true_time_offset, template_signal, label='moved orig')
axs[1].plot(template.t, template.signal, label='orig')
axs[1].plot(template.t + true_time_offset, template.signal, label='true moved orig')
axs[1].legend()
fig.savefig('figures/11_antenna_signals.pdf')
@ -154,17 +203,21 @@ if __name__ == "__main__":
# restore
axs[0].set_xlim(*old_xlims)
if True: # upsampled trace
upsampled_trace, upsampled_t = trace_upsampler(template_signal, antenna_signal, template_t, antenna_t)
if False:
plt.close(fig)
if True: # Show upsampled traces
axs2 = None
if True: # upsampled trace
upsampled_trace, upsampled_t = trace_upsampler(template.signal, antenna.signal, template.t, antenna.t)
if do_plots: # Show upsampled traces
fig2, axs2 = plt.subplots(1, sharex=True)
if not hasattr(axs2, '__len__'):
axs2 = [axs2]
axs2[-1].set_xlabel("Time [ns]")
axs2[0].set_ylabel("Amplitude")
axs2[0].plot(antenna_t, antenna_signal, marker='o', label='orig')
axs2[0].plot(antenna.t, antenna.signal, marker='o', label='orig')
axs2[0].plot(upsampled_t, upsampled_trace, label='upsampled')
axs2[0].legend(loc='upper right')
@ -175,68 +228,95 @@ if __name__ == "__main__":
axs2[0].set_xlim(x0-wx, x0+wx)
fig2.savefig('figures/11_upsampled_zoom.pdf')
if True:
plt.close(fig2)
# determine correlations with arguments
lag_dt = upsampled_t[1] - upsampled_t[0]
corrs, (out1_signal, out2_template, lags) = my_correlation(upsampled_trace, template_signal)
corrs, (out1_signal, out2_template, lags) = my_correlation(upsampled_trace, template.signal)
else: # downsampled template
raise NotImplementedError
corrs, (out1_signal, out2_signal, lags) = my_downsampling_correlation(template_signal, antenna_signal, template_t, antenna_t)
corrs, (out1_signal, out2_template, lags) = my_downsampling_correlation(template.signal, antenna.signal, template.t, antenna.t)
lag_dt = upsampled_t[1] - upsampled_t[0]
# Determine best correlation time
idx = np.argmax(abs(corrs))
best_sample_lag = lags[idx]
best_time_lag = best_sample_lag * lag_dt
if axs2:
time_residuals[j] = best_time_lag - true_time_offset
if do_plots and axs2:
axs2[-1].axvline(best_time_lag, color='r', alpha=0.5, linewidth=2)
# Show the final signals correlated
if True:
fig, axs = plt.subplots(3, sharex=True)
if do_plots:
fig, axs = plt.subplots(2, sharex=True)
ylabel_kwargs = dict(
rotation=0,
#rotation=0,
ha='right',
va='center'
)
axs[-1].set_xlabel("Time [ns]")
offset_list = [
[best_time_lag, dict(label=template.name, color='orange')],
[true_time_offset, dict(label='True offset', color='green')],
]
# Signal
i=0
axs[i].set_ylabel("Signal\nAmplitude", **ylabel_kwargs)
axs[i].plot(antenna_t, antenna_signal)
axs[i].set_ylabel("Amplitude", **ylabel_kwargs)
axs[i].plot(antenna.t, antenna.signal, label=antenna.name)
# Template
i=1
axs[i].set_ylabel("Template\nAmplitude", **ylabel_kwargs)
for offset in [0, best_time_lag]:
axs[i].axvline(offset + len(template_signal) * (template_t[1] - template_t[0]), color='g')
axs[i].axvline(offset, color='g')
axs[i].plot(offset + template_t, template_signal)
# Put template on an twinned axis (magnitudes are different)
ax2 = axs[i].twinx()
for i, offset_args in enumerate(offset_list):
this_kwargs = offset_args[1]
offset = offset_args[0]
ax2.axvline(offset + len(template.signal) * (template.t[1] - template.t[0]), color=this_kwargs['color'], alpha=0.7)
ax2.axvline(offset, color=this_kwargs['color'], alpha=0.7)
ax2.plot(offset + template.t, template.signal, **this_kwargs)
# Correlation
i=2
i=1
axs[i].set_ylabel("Correlation", **ylabel_kwargs)
axs[i].plot(lags * lag_dt, corrs)
axs[i].axvline(best_time_lag, color='r', ls='--')
for i, offset_args in enumerate(offset_list):
this_kwargs = offset_args[1]
offset = offset_args[0]
axs[i].axvline(offset, ls='--', **this_kwargs)
if True: # zoom
wx = len(template_signal) * (template_t[1] - template_t[0])/2
wx = len(template.signal) * (template.t[1] - template.t[0])/2
t0 = best_time_lag
for t in [t0-wx, t0+wx]:
axs[2].axvline(t, color='g')
old_xlims = axs[0].get_xlim()
axs[i].set_xlim( x0-wx, x0+3*wx)
fig.savefig('figures/11_corrs_zoom.pdf')
# restore
axs[i].set_xlim(*old_xlims)
fig.tight_layout()
fig.legend()
fig.savefig('figures/11_corrs.pdf')
#
time_residual = best_time_lag - true_time_offset
if False:
plt.close(fig)
print(time_residual, template_dt, antenna_dt)
# Make a plot of the time residuals
fig, ax = plt.subplots()
ax.set_title("Template Correlation Lag finding")
ax.set_xlabel("Time Residual [ns]")
ax.set_ylabel("#")
ax.hist(time_residuals, bins='sqrt', density=False)
ax.legend(title=f"template dt: {template.dt: .1e}ns\nantenna dt: {antenna.dt: .1e}ns")
fig.savefig("figures/11_time_residual_hist.pdf")
plt.show()