Module 3.1: Data Fitting
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Module 3.1: Data Fitting Wendy Tanamai & Albert Cerussi Beckman Laser Institute University of California, Irvine
description
Module 3.1: Data Fitting. Wendy Tanamai & Albert Cerussi Beckman Laser Institute University of California, Irvine. Outline. How data is fit Data file summary Using the GUI . How Data is Fit. FDPM Data Data inputs phase and amplitude vs. modulation frequency - PowerPoint PPT Presentation
Transcript of Module 3.1: Data Fitting
Module 3.1:Data Fitting
Wendy Tanamai & Albert Cerussi
Beckman Laser InstituteUniversity of California, Irvine
NTROI DOS Workshop, 2007 Module 3.1
Outline
• How data is fit
• Data file summary
• Using the GUI
NTROI DOS Workshop, 2007 Module 3.1
How Data is Fit
• FDPM Data– Data inputs
• phase and amplitude vs. modulation frequency• sample (tissue) and reference (phantom)
– Calibration for:• FDPM amplitude (ratio)• FDPM phase (difference)
NTROI DOS Workshop, 2007 Module 3.1
Raw FDPM
0 100 200 300 400 500 600
0
2000
4000
6000
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10000
PH
AS
E (
UN
CA
L)
FREQUENCY (MHz)
0 100 200 300 400 500 600
0.000
0.005
0.010
0.015
0.020A
MP
(UN
CA
L)
POSITION (mm)
NTROI DOS Workshop, 2007 Module 3.1
How Data is Fit
• FDPM Data (continued)– Conversion to Real & Imaginary– lsqcurvefit function in MATLAB using both real
and imaginary together– Some weighted fitting options– Done for each laser diode
NTROI DOS Workshop, 2007 Module 3.1
How Data is Fit
• Broadband Data– Dark count subtraction (usually done in
acquisition)– Spectral calibration
NTROI DOS Workshop, 2007 Module 3.1
Spectral Calibration
600 700 800 900 10000
8000
16000
24000
32000
40000
48000
56000
64000
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4R
AW
RE
FLE
CT
AN
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CO
UN
TS
WAVELENGTH (nm)
BR
OA
DB
AN
D C
OR
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CT
ED
NTROI DOS Workshop, 2007 Module 3.1
Spectral Calibration
600 700 800 900 10000
8000
16000
24000
32000
40000
48000
56000
64000
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4R
AW
RE
FLE
CT
AN
CE
CO
UN
TS
WAVELENGTH (nm)
BR
OA
DB
AN
D C
OR
RE
CT
ED
NTROI DOS Workshop, 2007 Module 3.1
How Data is Fit
• Broadband Data– Power Law fit to FDPM scattering– Scattering removed from broadband
reflectance– FDPM absorption used to scale broadband
reflectance– Solve for absorption using MATLAB ‘fzero’
NTROI DOS Workshop, 2007 Module 3.1
How Data is Fit
• Physiological Fitting– Assume 4-chromophores– Non-zero least squares– Usually fit with baseline
NTROI DOS Workshop, 2007 Module 3.1
Data Files (Acquired)
• All files are ASCII• FDPM data has ‘dcswitch’ tag
– for all modulation frequencies – one for each location
• SPEC data has ‘tis’ tag– for all wavelengths– one for each location
• Cal files named phantom/standard
NTROI DOS Workshop, 2007 Module 3.1
Data Files (Processed)
• _dBSUM file has all processed results for both FDPM (only) and FDPM-Broadband for all spatial locations
• _MUA file has broadband absorption spectra and chromophore fits for all spatial locations
• _MUS file has broadband reduced scattering spectra for all spatial locations
NTROI DOS Workshop, 2007 Module 3.1
Data Files (Processed)
• _dBMU file has all FDPM values for each wavelength and all spatial locations
• _specR has the calibrated/scaled broadband reflectance spectra for all spatial locations
• _gbfi (coming soon) quality of fit data for all fits and all spatial locations
NTROI DOS Workshop, 2007 Module 3.1
Data Files (Processed)
• Other processing options– Gridimager program (Visualization)– Double differential analysis (can download)– Bound Water/Temperature analysis
