The Diez Albums Gonnella, Julia; Weis, Friederike; Rauch, Christoph
2016, Volume:
11
eBook
The five Diez albums in Berlin are an important source for the study of Ilkhanid, Jalayirid, and Timurid art. The 21 essays of this book contribute to deepening our understanding of the development ...of Persianate art and its perception in later times.
We propose a straightforward and efficient fusion-based method for enhancing weakly illumination images that uses several mature image processing techniques. First, we employ an illumination ...estimating algorithm based on morphological closing to decompose an observed image into a reflectance image and an illumination image. We then derive two inputs that represent luminance-improved and contrast-enhanced versions of the first decomposed illumination using the sigmoid function and adaptive histogram equalization. Designing two weights based on these inputs, we produce an adjusted illumination by fusing the derived inputs with the corresponding weights in a multi-scale fashion. Through a proper weighting and fusion strategy, we blend the advantages of different techniques to produce the adjusted illumination. The final enhanced image is obtained by compensating the adjusted illumination back to the reflectance. Through this synthesis, the enhanced image represents a trade-off among detail enhancement, local contrast improvement and preserving the natural feel of the image. In the proposed fusion-based framework, images under different weak illumination conditions such as backlighting, non-uniform illumination and nighttime can be enhanced.
•A fusion-based method for enhancing various weakly illuminated images is proposed.•The proposed method requires only one input to obtain the enhanced image.•Different mature image processing techniques can be blended in our framework.•Our method has an efficient computation time for practical applications.
•An image correction method based on illumination reflection model and multi-scale theory.•The correction function is constructed on the Weber-Fechner Law.•The image fusion strategy is formulated and ...used to extract the details of the two images.•This method can improve the contrast of the image while reducing the impact of uneven illumination.
In this study, to improve the adaptability of image enhancement in images with low illumination, a colored image correction method based on nonlinear functional transformation according to the illumination-reflection model and multiscale theory is proposed. First, the original RGB image is converted to HSV color space, and the V component is used to extract the illumination component of the scene using the multiscale Gaussian function. Then, a correction function is constructed based on the Weber-Fechner law, and two images are obtained through adaptive adjustments to the image enhancement function parameters based on the distribution profiles of the illumination components. Finally, an image fusion strategy is formulated and used to extract the details from the two images. Compared with the classic algorithm, the proposed algorithm can improve the overall brightness and contrast of an image while reducing the impact of uneven illumination. The enhanced images appear clear, bright, and natural.
Balanced carrier diffusion in perovskitesThe efficient operation of solar cells based on inorganic-organic perovskites requires balanced transport of positive and negative charge carriers over long ...distances. Dong et al. used a top-seeded solution growth method to obtain millimeter-scale single crystals of the organolead trihalide perovskite CH3NH3PbI3. Under low light illumination, the electron and hole diffusion lengths exceeded 3 mm, and under full sunlight illumination, they exceeded 175 mu m.Science, this issue p. 967 Long, balanced electron and hole diffusion lengths greater than 100 nanometers in the polycrystalline organolead trihalide compound CH3NH3PbI3 are critical for highly efficient perovskite solar cells. We found that the diffusion lengths in CH3NH3PbI3 single crystals grown by a solution-growth method can exceed 175 micrometers under 1 sun (100 mW cm-2) illumination and exceed 3 millimeters under weak light for both electrons and holes. The internal quantum efficiencies approach 100% in 3-millimeter-thick single-crystal perovskite solar cells under weak light. These long diffusion lengths result from greater carrier mobility, longer lifetime, and much smaller trap densities in the single crystals than in polycrystalline thin films. The long carrier diffusion lengths enabled the use of CH3NH3PbI3 in radiation sensing and energy harvesting through the gammavoltaic effect, with an efficiency of 3.9% measured with an intense cesium-137 source.
In Illuminating Sanctity, Maria R. Grasso analyses the twelfth-century vita of Saint Amand. Her discovery and analysis of another set of preliminary drawings related to the miniature cycle ...demonstrates that a key alteration was made, isolating an important devotional image.
When one captures images in low-light conditions, the images often suffer from low visibility. Besides degrading the visual aesthetics of images, this poor quality may also significantly degenerate ...the performance of many computer vision and multimedia algorithms that are primarily designed for high-quality inputs. In this paper, we propose a simple yet effective low-light image enhancement (LIME) method. More concretely, the illumination of each pixel is first estimated individually by finding the maximum value in R, G, and B channels. Furthermore, we refine the initial illumination map by imposing a structure prior on it, as the final illumination map. Having the well-constructed illumination map, the enhancement can be achieved accordingly. Experiments on a number of challenging low-light images are present to reveal the efficacy of our LIME and show its superiority over several state-of-the-arts in terms of enhancement quality and efficiency.
As the appearance of a 3D surface texture is strongly dependent on the illumination direction, 3D surface-texture classification methods need to employ multiple training images captured under a ...variety of illumination conditions for each class. Texture images under different illumination conditions and directions still present a challenge for texture-image retrieval and classification. This paper proposes an efficient method for illumination-insensitive texture discrimination based on illumination compensation and enhancement. Features extracted from an illumination-compensated or -enhanced texture are insensitive to illumination variation; this can improve the performance for texture classification. The proposed scheme learns the average illumination-effect matrix for image representation under changing illumination so as to compensate or enhance images and to eliminate the effect of different and uneven illuminations while retaining the intrinsic properties of the surfaces. The advantage of our method is that the assumption of a single-point light source is not required, so it circumvents and overcomes the limitations of the Lambertian model and is also suitable for outdoor settings. We use a wide range of textures in the PhoTex database in our experiments to evaluate the performance of the proposed method. Experimental results demonstrate the effectiveness of our proposed methods.
The Word Illuminated Ben Azzouna, Nourane; Blair, Sheila S; Déroche, François ...
01/2023
eBook
Open access
Diplomatic gifts, war prizes, or library treasures of royal and princely libraries—handwritten Qurʾans have also been endowed to mosques, tombs, and other religious complexes to perpetuate and ...transmit their baraka (divine blessing). Artistic, historic, and religious contexts and materiality of Qurʾans are investigated, from use of costly materials such as gold and parchment to development of special scripts, intricate illuminated designs, and meticulously tooled bindings. This edited collection resulted from a 2016 symposium at the Smithsonian’s Arthur M. Sacker Gallery in conjunction with the exhibition The Art of the Qurʾan: Treasures from the Museum of Turkish and Islamic Arts.
High purity semi-insulating (HPSI) 4H-silicon carbide (SiC) was used to fabricate lateral and vertical photoconductive semiconductor switches (PCSSs). The lateral PCSSs were illuminated from the ...frontside (fPCSS) or the backside (bPCSS). The side-illuminated vertical PCSS (vPCSS) was designed to increase the light-matter interaction volume. A 532-nm pulsed laser with adjustable energy was utilized to excite the PCSSs. The turn-on time was found to be highly dependent on the optical illumination energy, and the full-width at half-maximum of the PCSSs output waveforms was related to the peak output voltage. The output electrical pulse from the vPCSS exhibited a shorter turn-on time and a larger pulsewidth than the two types of lateral PCSSs. The vPCSS outperformed the fPCSS and bPCSS in terms of minimum <inline-formula> <tex-math notation="LaTeX">\mathrm{\scriptscriptstyle ON} </tex-math></inline-formula>-state resistance and output pulse amplitude under the same optical illumination energy. The vPCSS, which utilizes a large effective contact area to collect photogenerated carriers, also had higher photon absorption efficiency by arranging the optical path at a right angle to the carrier transport. The vPCSS exhibited a minimum <inline-formula> <tex-math notation="LaTeX">\mathrm{\scriptscriptstyle ON} </tex-math></inline-formula>-state resistance of 0.34 <inline-formula> <tex-math notation="LaTeX">\Omega </tex-math></inline-formula> at optical illumination energy of 8 mJ.
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•Ease synthesis of mesoporous WO3–TiO2 nanocomposites were performed.•XRD and Raman spectra confirmed that monoclinic and triclinic of WO3 was detected.•The prepared photocatalysts ...were evaluated for photodegradation of imazapyr.•It could be completely degraded of imazapyr within 120min under UV light.•Under visible light, 0.5%WO3–TiO2 is the optimum with 46% photocatalytic efficiency.
Herein, we report the ease synthesis of mesoporous WO3–TiO2 nanocomposites at different WO3 contents (0–5wt%) together with their photocatalytic performance for the degradation of the imazapyr herbicide under visible light and UV illumination. XRD and Raman spectra indicated that the highly crystalline anatase TiO2 phase and monoclinic and triclinic of WO3 were formed. The mesoporous TiO2 exhibits large pore volumes of 0.267cm3g−1 and high surface areas of 180m2g−1 but they become reduced to 0.221cm3g−1 and 113m2g−1, respectively upon WO3 incorporation, with tunable mesopore diameter in the range of 5–6.5nm. TEM images show WO3–TiO2 nanocomposites are quite uniform with 10–15nm of TiO2 and 5–10nm of WO3 sizes. Under UV illumination, the overall photocatalytic efficiency of the 3% WO3–TiO2 nanocomposite is 3.5 and 6.6 times higher than that of mesoporous TiO2 and commercial UV-100 photocatalyst, respectively. The 3% WO3–TiO2 nanocomposite is considered to be the optimum photocatalyst which is able to degrade completely (100% conversion) of imazapyr herbicide along 120min with high photonic efficiency ∼8%. While under visible light illumination, the 0.5% WO3–TiO2 nanocomposite is the optimum photocatalyst which achieves 46% photocatalytic efficiency.
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