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Diffuse reflection of laser radiation by a biological tissue always gives rise to the formation of a biospeckle pattern. The biospeckle pattern depends on the surface irregularities and carries significant information about the surface roughness. Biospeckle imaging has been extensively applied to medicine, biology and agriculture for evaluating different types of biological tissues, since it is safe, simple and non-destructive optical method. In consequence of the texture properties of biospeckle pattern, various texture analysis methods have been presented in literature for extracting the information involved in biospeckle patterns. In this work, first, an experimental setup to simultaneously capture multiple biospeckle patterns from many cross-section areas of bovine articular cartilage tissue surface is investigated. Next, a new model based on local contrast measurement is proposed on the captured biospeckle patterns for final and proper estimation of the average roughness of the various cross-section areas of articular cartilage surface. The proposed model computes the local contrast for pairs of pixels at different neighborhood separation distances in order to obtain three contrast features. The obtained results showed that the contrast features can efficiently differentiate between the average roughness of the different cross-section areas of articular cartilage surface with 0.02 μm accuracy. [ABSTRACT FROM AUTHOR]

Optical parameters of biological tissues play an important role in tissue characterization, including the absorption and scattering coefficients and the anisotropy factor. These parameters are high wavelength dependent and give functional information of the tissue such as total haemoglobin content, tissue oxygenation and water fraction. However, estimating the optical properties of any tissue requires measurements of diffuse reflectance, diffuse transmittance and collimated transmittance. Experimentally, these measurements can be obtained either by integrating spheres techniques or with methods that based on distant detectors array. In this work, total diffuse reflectance and transmittance of native and dry chicken breast skin were measured in vitro via a single integrating sphere optical setup at 660 and 808 nm laser irradiation. Then, a combination between Kubellka-Munk model and Bouguer-Beer-Lambert law was used to estimate the three optical parameters from the collected data. The calculated optical parameters were then introduced to the diffusion equation to compute the optical fluence rate distribution at the boundary of the sample using the finite element method. The Monte-Carlo simulation method was implemented for validation showing absolute error of 0.002 and 0.009 at 660, 808 nm respectively for normal skin, 0.0013, and 0.0078 in dry skin. [ABSTRACT FROM AUTHOR]