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Light reflection and scattering. a Reflection and scattering phenomena at a point. b Reflection is classified into two components; diffuse and specular reflection. c Scattering is also classified into two components; single and multiple scattering. d Interreflections and multiple-scattering phenomena are similarly based on multi-bounce collisions
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An observed image is composed of multiple components based on optical phenomena, such as light reflection and scattering. Decomposing the observed image into individual components is an important process for various computer vision tasks. No general approach to combine them exists although many decomposition methods exist. This paper proposes a gen...
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... observed intensity at a point is a mixture of various optical components. Figure 1a illustrates light reflection and scattering phenomena at the point. Light reflection is often classified into two components; diffuse and specular reflection. ...
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... 1a illustrates light reflection and scattering phenomena at the point. Light reflection is often classified into two components; diffuse and specular reflection. Diffuse reflection arises because of a micro- facet structure on object surface. On the other hand, specular reflection arises at an interface between the air and the object surface (Fig. ...
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... scattering is also classified into two components; single and multiple scattering, according to researches in computer vision [42,50] and physics [51,52]. Single scattering is caused by one-bounce collision with a par- ticle, or particle aggregation, inside an object, which is often seen in optically thin media (Fig. 1c). A well-known nature of single scattering is that an intensity of single scattering exponentially decays along its light path. On the other hand, multiple scattering is a phenomenon of multi- bounce collisions, which is often seen in optically thick media (Fig. ...
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... aggregation, inside an object, which is often seen in optically thin media (Fig. 1c). A well-known nature of single scattering is that an intensity of single scattering exponentially decays along its light path. On the other hand, multiple scattering is a phenomenon of multi- bounce collisions, which is often seen in optically thick media (Fig. ...
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... observed images into the above four optical components; diffuse and specular reflection, and single and multiple scattering. Interreflections are not explicitly modeled in this imple- mentation. Since interreflections and multiple-scattering phenomena are similarly based on multi-bounce collisions with surfaces and inside particles, respectively (Fig. 1d), both of the components are included in the multiple- scattering ...
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... results. Each of the decomposition results is evaluated in peak signal-to-noise ratio (PSNR) between the others. The comparison resulted in 42.1 dB in PSNR on average with the standard deviation of 1.36 dB. The average (and the standard deviation) of PSNRs for diffuse and specular reflection, and single and multiple-scattering components are 42.1(1.58), 42.0(1.42), 42.2(1.15), and 42.0(1.24) dB, respectively. Consequently, it shows that the repeatability of the decomposition by the proposed approach is quite ...
Citations
... In light transport analysis, we can use other optical cues along with polarization. Previous works have already shown promising results by combining polarization with other cues such as color [37], high-frequency pattern [38], and Time-of-Flight [33]. Our method contributes to these previous and future methods to enable a comprehensive analysis of light transport, including higher-order multiple bounce reflection. ...
Polarization is well known for its ability to decompose diffuse and specular reflections. However, the existing decomposition methods only focus on direct reflection and overlook multiple reflections, especially specular inter-reflection. In this paper, we propose a novel decomposition method for handling specular inter-reflection of metal objects by using a unique polarimetric feature: the rotation direction of linear polarization. This rotation direction serves as a discriminative factor between direct and inter-reflection on specular surfaces. To decompose the reflectance components, we actively rotate the linear polarization of incident light and analyze the rotation direction of the reflected light. We evaluate our method using both synthetic and real data, demonstrating its effectiveness in decomposing specular inter-reflections of metal objects. Furthermore, we demonstrate that our method can be combined with other decomposition methods for a detailed analysis of light transport. As a practical application, we show its effectiveness in improving the accuracy of 3D measurement against strong specular inter-reflection.
... In essence, the whitening of unearthed jades is an optical phenomenon that it is dependent on components of light we observe, such as the reflection and scattering of light (Takatani et al., 2018). Specular reflection is very common for jades that have no corrosion, for example the area of jades showing a greasy luster or bright luster depends on angles of observer. ...
... Specular reflection is very common for jades that have no corrosion, for example the area of jades showing a greasy luster or bright luster depends on angles of observer. For the whitening jade, secondary white can be observed in all directions, which is likely to be associated with the depolarization caused by the diffuse reflection and multiple scattering of incident light on rough surfaces (Trost et al., 2013;Takatani et al., 2018). In the third stage, a lot of scattering factors are produced in the surface layer of eroded jades, such as innumerable etched micro-reflecting surfaces, etched micro-cracks and fine secondary minerals (Berner et al., 1980;Zhang et al., 1990;Velbel, 2011), which not only enhance the diffuse reflection on jades' surfaces (Nayar et al., 1991), but also provoke the multiple scattering of incident light between mineral grains in the etched layer. ...
Available online xxxx Liangzhu Culture in the lower reaches of the Yangtze River is world-famous for a large number of exquisite jade artifacts, but the provenance of nephrite materials has been a considerable controversy over the past several decades. Our research briefly summarizes evolutionary stages of unearthed nephrite artifacts, discusses a number of jades' secondary changes in the burial stage and then attempts to compare typical characteristics of Liangzhu jades with those of some nephrites within East Asia. The results show that although the weathering has obliterated some original information of Liangzhu jades, their residual information is still highly consistent with many aspects of Xiaomeiling nephrite, such as the mineral compositions, crystal morphology, textures of rocks and chemical compositions. These coincidences not only support that Xiaomeiling nephrite is one significant prove-nance of nephrites used by Liangzhu ancestors, but also reveal the hierarchical assignment system of Liangzhu Culture where Yuhang settlements dominate the allocation of jade resources. The distinct difference between different jade workshops in processing materials demonstrates convincingly that Liangzhu ancestors have been able to effectively identify some jade materials and a division of labor in the processing of jade artifacts has arisen, all of which support that Liangzhu Culture is a highly developed native civilization.
... When a wave is incident on a different position of a crest, there are three different deviations of reflected waves: specular reflection, inter-reflection, and scattering. 26 An EM wave that falls in a trough between the crests results in a specular reflection. Inter-reflection arises if an EM wave is repeatedly reflected on the surfaces of crests. ...
A ferrofluid layer separates into numerous subscale crests, which is referred to as Rosensweig instability, whose shape and size depend on the field condition and the composition of the ferrofluid. A ferrofluid consisting of nanoscale magnetite particles is also used as an electromagnetic (EM) wave absorption and reflection material. For this study, oil-based and mixture ferrofluid layers that split into various shapes of crests in the presence of an external magnetic field are used to form a protruding structure to reflect and scatter the EM wave and decrease EM radiation energy. For an identical field strength, a mixture ferrofluid layer splits into more crests than an oil-based ferrofluid. A mixture crest shows a less uniform size and shape than the oil-based one. A high-power green laser light is used as a visual EM wave emitting to a crest, which has varying tip angles, and to demonstrate the reflection and scattering. The reflection loss increases as the field strength is increased to create a crest of a smaller tip angle. The reflection loss of an EM wave is significantly affected by the transmitting position on a crest and the shape of a crest. Inter-reflection arises if an EM wave is repeatedly reflected on the surfaces of crests, which contributes to a significant reflection loss. An EM wave incident at an angle of 45° on a crest resulting in a larger area of the inter-reflection zone without specular reflection in a trough gives the most significant reflection loss.
