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| 2. |
- Dam, J. S, et al.
(författare)
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Fiber-optic probe for noninvasive real-time determination of tissue optical properties at multiple wavelengths
- 2001
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Ingår i: Applied Optics. - 2155-3165. ; 40:7, s. 1155-1164
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Tidskriftsartikel (refereegranskat)abstract
- We present a compact, fast, and versatile fiber-optic probe system for real-time determination of tissue optical properties from spatially resolved continuous-wave diffuse reflectance measurements. The system collects one set of reflectance data from six source-detector distances at four arbitrary wavelengths with a maximum overall sampling rate of 100 Hz. Multivariate calibration techniques based on two-dimensional polynomial fitting are employed to extract and display the absorption and reduced scattering coefficients in real-time mode. The four wavelengths of the current configuration are 660, 785, 805, and 974 nm, respectively. Cross-validation tests on a 6 x 7 calibration matrix of Intralipid-dye phantoms showed that the mean prediction error at, e.g., 785 nm was 2.8% for the absorption coefficient and 1.3% for the reduced scattering coefficient. The errors are relative to the range of the optical properties of the phantoms at 785 nm, which were 0-0.3/cm for the absorption coefficient and 6-16/cm for the reduced scattering coefficient. Finally, we also present and discuss results from preliminary skin tissue measurements. (C) 2001 Optical Society of America
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| 3. |
- Dam, J. S, et al.
(författare)
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Fiber optic system for in vivo real-time determination of tissue optical properties from steady-state diffuse reflectance measurements
- 2000
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Ingår i: PHOTON MIGRATION, DIFFUSE SPECTROSCOPY AND OPTICAL COHERENCE TOMOGRAPHY: IMAGING AND FUNCTIONAL ASSESSMENT. - : SPIE. - 0277-786X .- 1996-756X. - 0819438162 ; 1:31, s. 103-109
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Konferensbidrag (refereegranskat)abstract
- We present a versatile and compact fiber optic probe for real-time determination of the absorption and the reduced scattering coefficients from spatially resolved continuous wave diffuse reflectance measurements. The probe collects the diffuse reflectance at six distances in the range 0.6 - 7.8 mm at four arbitrary wavelengths, which were 660, 785, 805, and 974 nm in these experiments. The maximum sampling rate for one cycle of measurements including all four wavelengths is about 100 Hz. The absorption and the reduced scattering coefficients are extracted real-time from the probe measurements using multivariate calibration methods based on multiple polynomial regression and Newton-Raphson algorithms. The system was calibrated on a 6x7 matrix of Intralipid/ink phantoms with optical properties within typical biological ranges, e.g. at 785 nm, the ranges of the absorption and the reduced scattering coefficients, were 0 - 0.3 /cm and 6 - 16 /cm, respectively. Cross-validation tests shoved that the mean prediction error, relative to the ranges of absorption and the reduced scattering coefficients were 2.8 \% and 1.3 \%, respectively.
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| 4. |
- Fabricius, C, et al.
(författare)
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The spectro point spread function for GAIA
- 2002
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Ingår i: Astrophysics and Space Science. - 0004-640X. ; 280:1-2, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- We discuss the point spread function for the Spectro instrument based on realistic effects of the time delayed integration, transverse image motion and pixelization, but assuming rather small wave front errors. Stars brighter than 10 mag, which will saturate the CCD, may be observed photometrically using the image wings, but the central wavelengths will be slightly shifted towards the red.
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