Generating a Scanning Sequence File with Python

Speos provides you with an Python script file to help you understand how to create and generate the *.OPTScanSequence / *.txt file to be used in the LiDAR Speos definition.

To generate the *.OPTScanSequence / *.txt:

Prerequisites: Make sure your regional settings use a "." as decimal separator and not a ",".
Prerequisites: Download the speos_Firing_Sequence_File_Examples.zip file.
  1. Open the LiDAR_scanning_sequence_generator.py python script file.
    Note: From the Line 156, you will define the parameters to set as indicated by the comments. However the line numbering can vary according to the modifications you apply.
  2. From Line 162, define the PulseShape (Rectangular, Triangular, Gaussian, Dirac) and PulseWidth corresponding to the default width of pulses in seconds. 
    #setup default pulse shape
scan_sequence_data_model.EPulseShape = OptisCore.Enum_PulseShape(OptisCore.PulseShapeGaussian)
scan_sequence_data_model.PulseWidth = 0.001
  3. From Line 166, if you want to apply an unique wavelength, define the default monochromatic spectrum in nm. 
    # add a monochromatic spectrum
spectrum_Monochromatic = OptisCore.DSpectrumMonochromatic.Make()
spectrum_Monochromatic.Ptr().Wavelength = 950.0
scan_sequence_data_model.SpectrumList.Push_back(OptisCore.SharedPtr_Cast_DISpectrum_From_DSpectrumMonochromatic(spectrum_Monochromatic))
  4. From Line 171, ff you want to apply a spectrum with multiple wavelengths, define the sampled spectrum in nm. 
    # add a sampled spectrum
spectrum_Sampled = OptisCore.DSpectrumSampled.Make()

# Define the number of wavelength of the spectrum
numberOfWavelengths = 11
spectrum_Sampled.Ptr().Wavelengths.Resize(numberOfWavelengths)
spectrum_Sampled.Ptr().Values.Resize(numberOfWavelengths)

# Define the value of each wavelength
for i in range(numberOfWavelengths):
w = 945.0 + i * 10.0 / (numberOfWavelengths - 1)
spectrum_Sampled.Ptr().Wavelengths.Set(i, w)
spectrum_Sampled.Ptr().Values.Set(i, 25.0 - (w - 950.0) ** 2)
		
scan_sequence_data_model.SpectrumList.Push_back(OptisCore.SharedPtr_Cast_DISpectrum_From_DSpectrumSampled(spectrum_Sampled))
  5. From Line 184, define the intensity distribution of the beams. 
    # add an intensity distribution
numberOfPhiAngles = 5
numberOfThetaAngles = 13
intensity = OptisCore.DDistribution2Double.Make()
intensity.Ptr().Distribution.Allocate(numberOfPhiAngles, numberOfThetaAngles)

for p in range(numberOfPhiAngles):
intensity.Ptr().Distribution.m_X.Set(p, p * 360.0 / (numberOfPhiAngles - 1))

pos = OptisCore.Extent_uint_2()

for t in range(numberOfThetaAngles):
theta = 90.0 * t / (numberOfThetaAngles - 1)
intensity.Ptr().Distribution.m_Y.Set(t, theta)
pos.Set(1, t)

for p in range(numberOfPhiAngles):
pos.Set(0, p)
intensity.Ptr().Distribution.m_Value.Set(pos, math.cos(math.radians(theta))) # lambertian (no need to normalize)

scan_sequence_data_model.SampledIntensityList.Push_back(intensity)
  6. From Line 206, add as many beams as you want: 
    # add few beams:
scanParameters1 = OptisCore.DScanParam()
scanParameters1.Position.Init(0.1, 0.2, 0.3) # mm

# Choose between Rectangular and Elliptic
# Or for a Point shape, do not add the parameters ESurfaceShape, SizeX, SizeY
scanParameters1.ESurfaceShape = OptisCore.Enum_LidarEmissionSurfaceShape(OptisCore.LidarEmissionSurfaceShapeRectangular)
scanParameters1.SizeX = 3.0 # mm
scanParameters1.SizeY = 2.0 # mm

scanParameters1.ShootingTime = 0.001 # s

scanParameters1.PulseEnergy = 0.05 # J

# Choose between Triangular, Rectangular, Gaussian, Dirac
# Or use ShapeUndefined to use the PulseShape defined in Step 3
scanParameters1.EPulseShape = OptisCore.Enum_PulseShape(OptisCore.PulseShapeTriangular)

# If you want to use the PulseWidth defined in Step 3, do not add the parameter line for PulseWidth 
scanParameters1.PulseWidth = 0.00002 # s

# If you do not want to apply an angle, do not add the corresponding parameter line
scanParameters1.RotationAngle = 0.0132 # azimuth angle in degrees
scanParameters1.TiltAngle = 0.0276 # elevation angle degrees
scanParameters1.PsiAngle = 0.234 # degrees

# Choose between Gaussian and Sampled
# Or reomove the parameter line to use the Intensity defined in the Source - Intensity section's parameters from the LiDAR sensor definition
scanParameters1.EIntensityType = OptisCore.Enum_LidarIntensityType(OptisCore.LidarIntensityTypeSampled)

# If you selected Sampled as EIntensityType, add the following parameter line IntensityIndex and define its index
scanParameters1.IntensityIndex = 0

#If you selected Gaussian as EIntensityType, add the following parameter lines
scanParameters1.GaussianXWidth = 0.5 # FWHM in degrees
scanParameters1.GaussianYHeight = 0.5 # FWHM in degrees
scanParameters1.GaussianTotalAngle = 10.0 # degrees

scanParameters1.SpectrumIndex = 1

scan_sequence_data_model.ScanParamList.Push_back(scanParameters1)

    For each beam you add, define its parameters using the following template:

    scanParametersN = OptisCore.DScanParam()
scanParametersN.PARAMETER_TO_DEFINE
scanParametersN.PARAMETER_TO_DEFINE
...
...
scan_sequence_data_model.ScanParamList.Push_back(scanParametersN)
  7. From Line 249, define the *OPTScanSequence file name. 
    # serialization file
currentdirectory = os.path.dirname(os.path.realpath(__file__))
sequence_file_name = OptisCore.String(os.path.join(currentdirectory, "sampleFile.OPTScanSequence"))
sequence_filepath = OptisCore.Path(sequence_file_name)
  8. Close the Python script file and run it.
A *.OPTScanSequence file has been generated and is ready to be used in a LiDAR sensor definition.