text: HH = 'HH'
  VV = 'VV'
  VV_VH = 'VV+VH'
  HH_HV = 'HH+HV'
  DUAL_HH = ''
  DUAL_VV = ''
  DUAL_HV = ''
  DUAL_VH = ''
  HH_3SCAN = ''
  HH_4SCAN = ''
  HH_5SCAN = ''
  QUAD = 'quadrature'
  HH_VV = 'HH+VV'
  HH_HV_VH_VV = 'HH+HV+VH+VV'
  FULL = 'full'
  UNKNOWN = 'UNKNOWN'