def test_set_head():
acq = ismrmrd.Acquisition()
head = ismrmrd.AcquisitionHeader()
nsamples, nchannels, ntrajdims = 128, 8, 3
head.number_of_samples = nsamples
head.active_channels = nchannels
head.trajectory_dimensions = ntrajdims
acq.setHead(head)
eq_(acq.data.shape, (nchannels, nsamples))
eq_(acq.traj.shape, (nsamples, ntrajdims))
def test_header():
head = ismrmrd.AcquisitionHeader()
eq_(ctypes.sizeof(head), 340)
noiselevel = 0.05
K = np.zeros((nX, nY, ncoils, nreps), dtype=np.complex64)
for rep in range(nreps):
for coil in range(ncoils):
noise = noiselevel * (np.random.randn(nX, nY) +
1j * np.random.randn(nX, nY))
K[:, :, coil, rep] = np.fft.fftshift(
np.fft.fft2(np.fft.fftshift(C[:, :, coil] * rho + noise)))
rep0 = np.sqrt(np.sum(np.abs(K)**2, 2))
plt.imshow(rep0[:, :, 0])
for rep in range(nreps):
for line in range(nY):
# Generate header
head = ismrmrd.AcquisitionHeader()
counter = ismrmrd.EncodingCounters()
head.version = 1
head.number_of_samples = nX
head.center_sample = nX / 2
head.active_channels = ncoils
head.read_dir = [1., 0., 0.]
head.phase_dir = [0., 1., 0.]
head.slice_dir = [0., 0., 1.]
head.scan_counter = rep * nY + line
counter.kspace_encode_step_1 = line
counter.repetition = rep
head.idx = counter
# Note: the correct API for setting Acquisition flags looks like this:
# acq.setFlag(ismrmrd.FlagBit(ismrmrd.ACQ_FIRST_IN_ENCODE_STEP1))
# but using this API would require using only ugly "acq.setXXX" methods