A three‐camera close range photogrammetric system for robust and precise measurement of bedsores has been designed and constructed. MEDPHOS (MEDical PHOtogrammetric System) consists of three synchronised cameras with convergent optical axes. A light projector is fixed in the centre of the rig that holds the cameras. A special dot pattern is projected onto the surface to be measured, to compensate for the lack of natural texture on the wound surface. The proposed algorithm consists of the following steps: the cameras and projector are calibrated so that all interior and exterior parameters are known; tailored image segmentation procedures are developed and applied for the detection of the projected pattern dots from the uneven background of the images using morphologic operators; and watershed transformation is used to tackle the problem of overlapping pattern dots. To reduce the effects of non‐uniform illumination and specular reflection of light due to humidity (often the case with wounds), a homomorphic transformation is developed and applied to the images. After segmentation of the images, a connected‐component labelling procedure is used to establish the points for matching. The centroids of these components were precisely calculated. Intensity‐based image matching has been tested without yielding satisfactory results due to the significant deviation from the Lambertian reflection assumption used for solving the correspondence problem. This problem is reliably solved by developing a new algorithm based on geometric constraints that allow feature‐based matching and do not need approximate values of the location of the targets in the images. This robust three‐focal constraint is found to be very effective for matching provided the necessary conditions for the system configuration are met. Auxiliary photometric constraints together with the calibrated projector (which is treated like an active camera) also serve as additional sources of information for reducing the number of remaining ambiguities and checking the consistency of the results. Almost all of the required biometric information can be obtained rapidly, robustly and easily using MEDPHOS. Experimental results showed the effectiveness of the proposed technique.

No abstract

No abstract

With the help of temperature dependence, Raman scattering anharmonic effect of various modes of layered semiconductor InSe over temperature range of 20–650 K has been studied. It was found that with an increase in temperature, anharmonicity will increase. Two and three phonons coupling with optical phonon, are used to describe temperature-induced anharmonicity in the linewidth of Raman modes. It was found that the temperature variation of the phonon parameter can be accounted for well by the cubic term in anharmonic model. To describe line-center shift of Raman modes, a model not considering independently cubic and quartic anharmonicity was used. A similar study has been done for InSe doped with different concentration of GaS dopant. The result of temperature study of InSe doped with GaS revealed that in this case anharmonicity increases with an increase in dopant and an increase in temperature.

A comparative study of antiresonance effects in InSe and InSe doped with GaS, using the resonant Raman spectroscopy is presented. The nonpolar optical phonon of 1 1g A symmetry in InSe exhibits a pronounced decrease in the Raman cross-section at excitation energy 2.585 eV. In InSe doped with GaS samples, it is found that the anti-resonance behavior decreases as doping contents are increased. To account these observations, a model is applied to explain and interpret the Raman intensity evolution versus incident photon energy. The agreement between theory and experiment is good.