Elimination of single-beam substitution error in diffuse reflectance measurements using an integrating sphere

Diffuse reflectance spectra (DRS) of biological samples are commonly measured using an integrating sphere (IS), in which spectrally broad illumination light is multiply scattered and homogenized. The measurement begins by placing a highly reflective white standard against the IS sample opening and collecting the reflected light at the signal output port to account for illumination field. After replacing the white standard with test sample of interest, DRS of the latter is determined as the ratio of the two values at each involved wavelength. However, because test samples are invariably less reflective than the white standard, such a substitution modifies the illumination field inside the IS. This leads to underestimation of the sample’s reflectivity and distortion of measured DRS, which is known as single-beam substitution error (SBSE). Barring the use of much more complex dual-beam experimental setups, involving dedicated IS, literature states that only approximate corrections of SBSE are possible, e.g., by using look-up tables generated with calibrated low-reflectivity standards. We present a practical way to eliminate the SBSE using IS equipped with an additional “reference” output port. Two additional measurements performed at this port (of the white standard and sample, respectively) namely enable an accurate compensation for above described alteration of the illumination field. In addition, we analyze the dependency of SBSE on sample reflectivity and illustrate its impact on measurements of DRS in human skin with a typical IS.

[1]  Efthimios Kaxiras,et al.  Melanin absorption spectroscopy: new method for noninvasive skin investigation and melanoma detection. , 2008, Journal of biomedical optics.

[2]  F. Clarke,et al.  Correction Methods for Integrating Sphere Measurement of Hemispherical Reflectance , 1987 .

[3]  S. Pollak,et al.  Spectrophotometric evaluation of the colour of intra- and subcutaneous bruises , 2000, International Journal of Legal Medicine.

[4]  I. Yaroslavsky,et al.  Optical properties of selected native and coagulated human brain tissues in vitro in the visible and near infrared spectral range. , 2002, Physics in medicine and biology.

[5]  Anthony J. Durkin,et al.  Chromophore concentrations, absorption and scattering properties of human skin in-vivo. , 2009, Optics express.

[6]  Dmitry Yudovsky,et al.  Retrieving skin properties from in vivo spectral reflectance measurements , 2011, Journal of biophotonics.

[7]  S R Arridge,et al.  Recent advances in diffuse optical imaging , 2005, Physics in medicine and biology.

[8]  A. P. Ivanov,et al.  Role of epidermis in the optics and thermal physics of human skin , 2009 .

[9]  A. N. Bashkatov,et al.  Optical properties of human skin, subcutaneous and mucous tissues in the wavelength range from 400 to 2000 nm , 2005 .

[10]  N. Langlois,et al.  The practical application of reflectance spectrophotometry for the demonstration of haemoglobin and its degradation in bruises , 2004, Journal of Clinical Pathology.

[11]  R. Doornbos,et al.  The determination of in vivo human tissue optical properties and absolute chromophore concentrations using spatially resolved steady-state diffuse reflectance spectroscopy. , 1999, Physics in medicine and biology.

[12]  Tom Lister,et al.  Spectrophotometers for the clinical assessment of port-wine stain skin lesions: a review , 2010, Lasers in Medical Science.

[13]  Valery V. Tuchin,et al.  Optical properties of melanin in the skin and skinlike phantoms , 2000, European Conference on Biomedical Optics.

[14]  Werner Gellermann,et al.  Dermal carotenoid measurements via pressure mediated reflection spectroscopy , 2012, Journal of biophotonics.

[15]  L. O. Svaasand,et al.  A novel approach to age determination of traumatic injuries by reflectance spectroscopy , 2006, Lasers in surgery and medicine.

[16]  InSeok Seo,et al.  Interpreting diffuse reflectance for in vivo skin reactions in terms of chromophores , 2009, Journal of biophotonics.

[17]  Wiley Interscience,et al.  Methemoglobin formation during laser induced photothermolysis of vascular skin lesions , 2004, Lasers in surgery and medicine.

[18]  N. Kollias,et al.  In vivo measurement of skin erythema and pigmentation: new means of implementation of diffuse reflectance spectroscopy with a commercial instrument , 2008, The British journal of dermatology.

[19]  R J Ott,et al.  Spectrophotometric assessment of pigmented skin lesions: methods and feature selection for evaluation of diagnostic performance. , 2000, Physics in medicine and biology.

[20]  Sheng-Hao Tseng,et al.  Noninvasive evaluation of collagen and hemoglobin contents and scattering property of in vivo keloid scars and normal skin using diffuse reflectance spectroscopy: pilot study. , 2012, Journal of biomedical optics.

[21]  Guillermo Aguilar,et al.  Determination of human skin optical properties from spectrophotometric measurements based on optimization by genetic algorithms. , 2005, Journal of biomedical optics.

[22]  Ingemar Fredriksson,et al.  Accuracy of vessel diameter estimated from a vessel packaging compensation in diffuse reflectance spectroscopy , 2011, European Conference on Biomedical Optics.

[23]  Elena Salomatina,et al.  Optical properties of normal and cancerous human skin in the visible and near-infrared spectral range. , 2006, Journal of biomedical optics.

[24]  A. Roos,et al.  Evaluation of correction factors for transmittance measurements in single-beam integrating spheres. , 1994, Applied optics.

[25]  Narasimhan Rajaram,et al.  Experimental validation of the effects of microvasculature pigment packaging on in vivo diffuse reflectance spectroscopy , 2010, Lasers in surgery and medicine.