>>> """
============
MRI With EEG
============

Displays a set of subplots with an MRI image, its intensity
histogram and some EEG traces.
"""
... 
... import numpy as np
... import matplotlib.pyplot as plt
... import matplotlib.cbook as cbook
... import matplotlib.cm as cm
... 
... from matplotlib.collections import LineCollection
... from matplotlib.ticker import MultipleLocator
... 
... fig = plt.figure("MRI_with_EEG")
... 
... # Load the MRI data (256x256 16 bit integers)
... with cbook.get_sample_data('s1045.ima.gz') as dfile:
...     im = np.frombuffer(dfile.read(), np.uint16).reshape((256, 256))
... 
... # Plot the MRI image
... ax0 = fig.add_subplot(2, 2, 1)
... ax0.imshow(im, cmap=cm.gray)
... ax0.axis('off')
... 
... # Plot the histogram of MRI intensity
... ax1 = fig.add_subplot(2, 2, 2)
... im = np.ravel(im)
... im = im[np.nonzero(im)]  # Ignore the background
... im = im / (2**16 - 1)  # Normalize
... ax1.hist(im, bins=100)
... ax1.xaxis.set_major_locator(MultipleLocator(0.4))
... ax1.minorticks_on()
... ax1.set_yticks([])
... ax1.set_xlabel('Intensity (a.u.)')
... ax1.set_ylabel('MRI density')
... 
... # Load the EEG data
... n_samples, n_rows = 800, 4
... with cbook.get_sample_data('eeg.dat') as eegfile:
...     data = np.fromfile(eegfile, dtype=float).reshape((n_samples, n_rows))
... t = 10 * np.arange(n_samples) / n_samples
... 
... # Plot the EEG
... ticklocs = []
... ax2 = fig.add_subplot(2, 1, 2)
... ax2.set_xlim(0, 10)
... ax2.set_xticks(np.arange(10))
... dmin = data.min()
... dmax = data.max()
... dr = (dmax - dmin) * 0.7  # Crowd them a bit.
... y0 = dmin
... y1 = (n_rows - 1) * dr + dmax
... ax2.set_ylim(y0, y1)
... 
... segs = []
... for i in range(n_rows):
...     segs.append(np.column_stack((t, data[:, i])))
...     ticklocs.append(i * dr)
... 
... offsets = np.zeros((n_rows, 2), dtype=float)
... offsets[:, 1] = ticklocs
... 
... lines = LineCollection(segs, offsets=offsets, transOffset=None)
... ax2.add_collection(lines)
... 
... # Set the yticks to use axes coordinates on the y axis
... ax2.set_yticks(ticklocs, labels=['PG3', 'PG5', 'PG7', 'PG9'])
... 
... ax2.set_xlabel('Time (s)')
... 
... 
... plt.tight_layout()
... plt.show()
...