write_external_field_map.py
0bdc8a6b65demaster

write_external_field_map.py
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			import math

			import numpy as np

			from pypulseq.Sequence.sequence import Sequence
			from pypulseq.calc_duration import calc_duration
			from pypulseq.make_adc import make_adc
			from pypulseq.make_sinc_pulse import make_sinc_pulse
			from pypulseq.make_trap_pulse import make_trapezoid

			seq = Sequence()
			fov = 220e-3
			Nx, Ny = 256, 256

			blip_amp = 0.2

			rf, gz, _ = make_sinc_pulse(flip_angle=20 * math.pi / 180, duration=4e-3, slice_thickness=5e-3, apodization=0.5,
			time_bw_product=4)

			delta_k = 1 / fov
			gx = make_trapezoid(channel='x', flat_area=Nx * delta_k, flat_time=6.4e-3)
			adc = make_adc(num_samples=Nx, duration=gx.flat_time, delay=gx.rise_time)
			gx_pre = make_trapezoid(channel='x', area=-gx.area / 2, duration=2e-3)
			gz_reph = make_trapezoid(channel='z', area=-gz.area / 2, duration=2e-3)
			phase_areas = (np.arange(Ny) - Ny / 2) * delta_k

			delay_TE = 10e-3 - calc_duration(gx_pre) - calc_duration(rf) / 2 - calc_duration(gx) / 2
			delay_TR = 40e-3 - calc_duration(gx_pre) - calc_duration(rf) - calc_duration(gx) - delay_TE

			g1 = make_trapezoid()
			# TODO Bug in Matlab