PyOCT 2.0.6

OCT imaging reconstruction on spectral-domain optical coherence tomography

PyOCT: Imaging Reconstruction for Spectral-Domain Optical Coherence Tomography

PyOCT is developed to conduct normal spectral-domain optical coherence tomography (SD-OCT) imaging reconstruction with main steps as:

1. Reading Data
2. Background Subtraction
3. Spectral Resampling
4. Comutational Aberration Correction (Alpha-correction)
5. Camera Dispersion Correction (Beta-correction with camera calibration factors)
6. Inverse Fourier Transform
7. Obtain OCT Image

The algorithms was developed initially in Prof. Steven G. Adie research lab at Cornell University using MATLAB. The reconstruction speed has been improved with matrix-operation. Compared with MATLAB, Python language have a much better performance in loading data from binary files tested only in our lab computer. Currently, PyOCT only supports python 3.0+.

Quick start

PyOCT can be install using pip:

$pip install PyOCT

If you want to run the latest version of the code, you can install from git:

$python -m pip install -U git+git://github.com/NeversayEverLin/PyOCT.git

After successful installaiton, you can test program under python environment:

$from PyOCT import VolumeReconstruction
$VolumeReconstruction.Run_test() 

To run the OCT imaging reconstruction, you can construct class OCTImagingProcessing() from PyOCTRecon module:

$from PyOCT import PyOCTRecon 
$OCTImage = PyOCTRecon.OCTImagingProcessing()  

Class OCTImagingProcessing require at least 3 positional arguments. All input parameters are:

• root_dir: required, root directory path where OCT raw data located, ENDING WITHOUT /; e.g., root_dir = 'D:/cuda_practice/OCT_Recon/OCTdata'.
• SampleData: optional, sample data, most of time won't need.
• Settings: optional, Settings, most time won't need.
• sampleID: required, sample data file name. ENDING WITHOUT _raw.bin; e.g., sampleID = 'OCT_100mV_2'.
• bkgndID: required, background data file name, ending with _raw.bin; e.g., bkgndID = 'bkgnd_512_0_raw.bin'.
• Sample_sub_path: optional, default as None; sub-directory where OCT raw data located. ENDING WITHOUT /.
• Bkgnd_sub_path: optional, default as None; sub-directory where OCT bkgnd data located. ENDING WITHOUT /.
• saveOption: optional, bool, default as False.
• saveFolder: optional, name for folder to save data; default as None, which will save data in root directory.
• RorC: optional,"real" or "complex", tell to save data or show data in complex format or single precison (float32) format.
• verbose: optional, bool, default as True. If True, the data processing will show processing information during each step.
• frames: optional, int, number of frames to read and process, defaults as 1.
• alpha2, alpha3: optional, parameters for computational dispersion correction.
• depths: optional, nuumpy.linspace() created array, depths to be processed, default as: np.linspace(1024,2047,1024), indicating procesing 1024th z-pixel to 2048-pixel.
• gamma: optional, power factor to do plotting, default as 0.4.
• wavelength: optional, nominal central wavelength of OCT laser source in unit of nm, default as 1300.
• XYConversion: optional, 2 elements numpy array, calibration factor for galvo-scanning voltage to scanning field of view in x and y axis at unit of um/V, default as [660,660].
• camera_matrix: optional, camera dispersion correction factor, numpy array as [c0,c1,c2,c3]; default as np.asarray([1.169980E3,1.310930E-1,-3.823410E-6,-7.178150E-10]) for 1300nm system.
• start_frame: which frame to start reading and being processed. default is 1, indicating starting from first frame.
• OptimizingDC: [Required Further Developement] optional, bool, optimizing dispersion correction to search optimized alpha2 and alpha3. default as False.
• singlePrecision: only workable when RorC = 'real', Default as True, data will be converted into numpy.float32 single precision data type.
• ReconstructionMethods: 'cao' or 'nocao', default as 'NoCAO'. using bkgnd data as real time background estimation from signal dataset ("CAO") or directly from bkgnd file ("NoCAO")

Another class in PyOCT is Batch_OCTProcessing(), which using data processing provided by class OCTImagingProcessing() with additional inputs as:

• Ascans: number of Ascans.
• Frames: number of frames.
• ChunkSize: number of frames at each sub-segmentation dataset.

Batch_OCTProcessing() should be used when dataset is too large to be directly processed by whole volume which might exhaust your RAM/CPU. It will automatically segmented dataset into sub-segmentation dataset to be processed. The processed volume data and settings could be accessed by Batch_OCTProcessing.data or Batch_OCTProcessing.OCTData and Batch_OCTProcessing.Settings. You can still access to basic OCTImagingProcessing methods by accessing to methods like Batch_OCTProcessing.OCTRe.ShowXZ().

Class OCTImagingProcessing also provides several accesses/members to imaging processing data:

• self.root_dir: root directory of data set
• self.sampleID: sample ID
• self.bkgndID: background ID
• self.Settings: parameters of settings of reconstruction
• self.OCTData: single precision OCT intensity data
• self.data: complex OCT reconstruction data, only accessible when datatype is not "real".
• self.InterferencePattern: interference fringes of OCT imaging
• self.DepthProfile: depth profile (along z-axis) of reconstructed image
• self.ShowXZ(OCTData): member function to show cross-section.

Example dataset could be download under the request to email address: [e-mail]

License

PyOCT is licensed under the terms of the MIT License (see the file LICENSE).# PyOCT