Reflection imaging

The goal of URT is to obtain reflectivity images from back-scattered measurements. This consists in a Fourier synthesis problem, and the first task is to correctly cover the frequency space of the "object" r. Let for simplicity the dimension of the physical space be 2. 

Gloss, or surface luster, is the property of a surface to reflect light specularly. It is associated with such phenomena as shininess, highlight, and reflected images. The gloss of paper is usually quantified with a spectrophotometer which measures light at a variety of angles of incidence and reflection. 

The TSM can be modified for reflected light confocal microscopy (TSRLM). In that case, one Nipkow disk above the objective serves both for the illuminating beams and the reflected image-forming rays. 

The general brightness of a surface is chiefly dependent upon the total reflectivity T, while specular reflectivity S controls the character of the reflected image. In assessing the subjective brightness of a surface the eye tends to be influenced more by the S/Tratio or image clarity than by the total reflectivity. 

As an alternative, changes in relative intensity of the laser lines may be directly recorded using for example, reflection images or a transmission detector, and y may be adjusted accordingly. In our experience, this works significantly less reliable. 

Reflection contrast Reflection-imaging microscopy Field ion microscopy Quantification in gap between light and em microscopies Useful for imaging highly reflective particles such as silver grains in autoradiographs Atomic structure of crystals Immunoelectron Localization of cellular antigens... 

Further processing is also usually performed to transform the reflectance image cube to its logic (UR) form, which is effectively the sample absorbance . This results in chemical images in which brightness linearly maps to the analyte concentration, and is generally more useful for comparative as well as quantitative purposes. Note that for NIR measurements of undiluted solids the use of more rigorous functions such as those described by Kubelka and Munk are usually not required. ... 

A Mobius band is an example of a nonorientable space. This means, in theory, it is not possible to distinguish an object on the surface from irs reflected image. The surface is considered nonorientable if it has a path that reverses the orientation of creatures living on the surface, as described in the previous paragraph. On the other hand, if a space preserves the handedness of an asymmetric structure, regardless of how the structure is moved about, the space is called orientable. ... 

Oscillation photography can be used in tandem with area detectors, but detector resolution limits the size of the unit cell from which data can be collected. Large unit cells, such as those of virus capsids, mean small reciprocal unit cells and large numbers of closely spaced reflections. Image plates are commonly used in such cases because of their greater spatial resolution. 

Weiss (2001) describes how a reflectance image may be obtained from an image sequence taken with a stationary camera. Obviously, if the camera is stationary and no moving objects... 

Hurlbert and Poggio (1987, 1988) have shown that color constancy may be learnt from examples. Owing to computational constraints, they worked on individual lines of simulated color Mondrians. The color Mondrians were created by artificially illuminating a reflectance image of a color Mondrian with illumination gradients. In their model, the measurement made by the sensor / is proportional to the product of the illumination intensity L and the surface reflectance R. 

Figure 8.9 Performance of best evolved individual on three different fitness cases. The images in the first row show the reflectance images. The images in the second row show the virtual illuminant. The images in the third row show the input images presented to the individual. The images in the fourth row show the illuminant that was estimated by the evolved individual. In the last row, the estimated reflectance is shown. (Reproduced from Ebner M. 2006 Evolving color constancy. Special issue on evolutionary computer vision and image understanding of pattern recognition letters, Elsevier, 27(11), 1220-1229, by permission from Elsevier.)...

Near-infrared reflectance imaging is a popular technique for spatially monitoring chemical species in agricultural materials.102-115 The technique has been used to investigate maize kernels,116 sugar content in the flesh of melons117 and soluble solids in kiwifruit.118... 

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