Diverse plumages have evolved among birds through complex morphological modifications. We investigate how the interplay of light with surface and subsurface feather morphology determines the direction of light propagation, an understudied aspect of avian visual signalling. We hypothesize that milli-scale modifications of feathers produce anisotropic reflectance, the direction of which may be pr...

Decreased leaf moisture content, typically measured as equivalent water thickness (EWT), is an early signal of tree stress caused by drought, disease, or pest insects. We investigated the use of two terrestrial laser scanners (TLSs) employing different wavelengths for improving the understanding how EWT can be retrieved in a laboratory setting. Two wavelengths were examined for normalizing the ...

1 The reflectance of light from the surface of an object is modelled by a new technique, using components extracted from a set of 64 images taken in an illumination dome, Techniques of photometric stereo are used to determine albedo and surface normals at each pixel. The ratio of actual to diffuse reflectance is modelled to find the specular angle and an angular distribution of intensity based ...

0167-8655/$ see front matter 2008 Elsevier B.V. A doi:10.1016/j.patrec.2008.04.007 * Corresponding author. Tel.: +44 131 451 3423; fa E-mail address: [email protected] (A.M. Wall We present a method to recover the reflectance of objects and the parameters of multiple lights using a 3D image acquired by a depth sensor and a stereo intensity pair. Experimental evaluation shows the ability to r...

We present a framework that captures and synthesizes high resolution facial geometry and performance. In order to capture highly detailed surface structures, a theory of fast normal recovery using spherical gradient illumination patterns is presented to estimate surface normal maps of an object from either its diffuse or specular reflectance, simultaneously from any viewpoints. We show that the...

The reflectance spectra of the human skin in visible and near-infrared (NIR) spectral region have been calculated using the Monte Carlo technique, and the specular and internal reflection on the medium surface is taken into account. Skin is represented as a complex inhomogeneous multi-layered highly scattering and absorbing medium. The model takes into account variations in spatial distribution...

We constructed an automated reflectometry system for accurate measurement of coherent reflectance curves of turbid samples and analyzed the presence of coherent and diffuse reflection near the specular reflection angle. An existing method has been validated to determine the complex refractive indices of turbid samples on the basis of nonlinear regression of the coherent reflectance curves by Fr...

A new reflectometer-spectrophotometer has been designed and constructed using state-of-the-art technology to enhance optical properties of materials measurements over the ultraviolet, visible, and near-infrared (UV-Vis-NIR) wavelength range (200 nm to 2500 nm). The instrument, Spectral Tri-function Automated Reference Reflectometer (STARR), is capable of measuring specular and diffuse reflectan...

The thermodynamics of the rapid vaporization of a liquid on a solid surface heated by an excimer laser pulse is studied experimentally. The transient temperature field is measured by monitoring the photothermal reflectance of an embedded thin film in nanosecond time resolution. The transient reflectivity is calibrated by considering a temperature gradient across the sample based on the static m...