bval_extract.py

def save_diffusion_vec(dcm_files, out_bvecs, out_bvals):
    bvals = []
    bvecs = []
    for dcm_file in dcm_files:
        dcm_dat = dicom.read_file(dcm_file)
        csa = nibabel.nicom.csareader.get_csa_header(dcm_dat)
        bval = nibabel.nicom.csareader.get_b_value(csa)
        bvec = nibabel.nicom.csareader.get_g_vector(csa)
        bvals.append(bval)
        bvecs.append(bvec)
    bvals = np.array(bvals)    
    bvecs = np.array(bvecs)
    np.savetxt(out_bvecs, bvecs.T, delimiter=" ", fmt='%.4g')
    np.savetxt(out_bvals, bvals.reshape(-1,1).T, delimiter=" ", fmt='%.4g')