The appearance of a soil results from the interaction of its different constituents with incident light. Color and various other attributes of the appearance of soil are highly sensitive to the nature, proportion, particle size and morphology, and spatial association of its mineral and organic components. In fact, color has been used for more than 75 yr to obtain information about these soil pr...

The use of a mobile phone for classification and quantification of liquid samples is described. The screen of the phone is used for controlled illumination and the front side camera for imaging. No additional optical equipment is needed. It is shown that there are different regions of the captured image containing different information about the sample. One region contains light that has been s...

We introduce a novel fitting procedure that takes as input an arbitrary material, possibly anisotropic, and automatically converts it to a microfacet BRDF. Our algorithm is based on the property that the distribution of microfacets may be retrieved by solving an eigenvector problem that is built solely from backscattering samples. We show that the eigenvector associated to the largest eigenvalu...

We propose a technique to modify colors in photographic images predicting the color appearance of objects in an image under different illuminations. Using the dichromatic surface reflectance model, we estimate the illumination spectrum and the spectrum of the diffuse surface reflectance via the color histogram and subspace analyses. With this estimated spectral information, and the spectrum of ...

Subwavelength nanostructured surfaces are realized with self-assembled vertically-aligned InAs nanowires, and their functionalities as optical reflectors are investigated. In our system, polarization-resolved specular reflectance displays strong modulations as a function of incident photon energy and angle. An effective-medium model allows one to rationalize the experimental findings in the lon...

We propose a method for rapidly classifying surface reflectance directly from the output of spatiotemporal filters applied to an image sequence of rotating objects. Using image data from only a single frame, we compute histograms of image velocities and classify these as being generated by a specular or a diffusely reflecting object. Exploiting characteristics of material-specific image velocit...

[1] Synthetic olivine samples ranging in composition from forsterite to fayalite are analyzed in the midinfrared using thermal emission, specular and diffuse reflectance, and attenuated total reflectance spectroscopies to study the spectral effects of Mg‐Fe solid solution. For each method, fundamental bands gradually change in position and strength from Mg2SiO4 at larger wave numbers to Fe2SiO4...

The analysis of monomolecular layers has traditionally been a challenging spectroscopic measurement due to the relatively low signal obtained from the sample. Specular reflectance at high “grazing” angles (around 80 degrees from normal to the surface) has been recognized as one of the best spectroscopic techniques to monitor monomolecular layers on reflective surfaces due to the enhancement of ...