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[ACM Press SIGGRAPH Asia 2018 Posters - Tokyo, Japan (2018.12.04-2018.12.07)] SIGGRAPH Asia 2018 Posters on - SA '18 - Spectral rendering of fluorescence using importance sampling
摘要： Spectral rendering is necessary for rendering a scene with fluorescence, because fluorescence is a strongly wavelength dependent phenomenon. We propose a method for rendering fluorescence under global illumination environment efficiently by using importance sampling of wavelength considering both spectra of fluorescent materials and light sources.
关键词： global illumination,spectral rendering,importance sampling,Fluorescence
更新于2025-09-09 09:28:46
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The Post-Illumination Pupil Response (PIPR)
摘要： The post-illumination pupil response (PIPR) has been quantified using four metrics, but the spectral sensitivity of only one is known; here we determine the other three. To optimize the human PIPR measurement, we determine the protocol producing the largest PIPR, the duration of the PIPR, and the metric(s) with the lowest coefficient of variation. METHODS. The consensual pupil light reflex (PLR) was measured with a Maxwellian view pupillometer. Experiment 1: Spectral sensitivity of four PIPR metrics (plateau, 6 seconds, area under curve early and late recovery) was determined from a criterion PIPR to a 1-second pulse and fitted with vitamin A1 nomogram (kmax ? 482 nm). Experiment 2: The PLR was measured as a function of three stimulus durations (1 second, 10 seconds, 30 seconds), five irradiances spanning low to high melanopsin excitation levels (retinal irradiance: 9.8–14.8 log quanta.cm(cid:2)2.s(cid:2)1), and two wavelengths, one with high (465 nm) and one with low (637 nm) melanopsin excitation. Intra- and interindividual coefficients of variation (CV) were calculated. RESULTS. The melanopsin (opn4) photopigment nomogram adequately describes the spectral sensitivity of all four PIPR metrics. The PIPR amplitude was largest with 1-second short-wavelength pulses (?12.8 log quanta.cm(cid:2)2.s(cid:2)1). The plateau and 6-second PIPR showed the least intra- and interindividual CV ((cid:3)0.2). The maximum duration of the sustained PIPR was 83.0 6 48.0 seconds (mean 6 SD) for 1-second pulses and 180.1 6 106.2 seconds for 30-second pulses (465 nm; 14.8 log quanta.cm(cid:2)2.s(cid:2)1). CONCLUSIONS. All current PIPR metrics provide a direct measure of the intrinsic melanopsin photoresponse. To measure progressive changes in melanopsin function in disease, we recommend that the PIPR be measured using short-duration pulses (e.g., (cid:3)1 second) with high melanopsin excitation and analyzed with plateau and/or 6-second metrics. Our PIPR interstimulus intervals between duration data provide a baseline for the selection of consecutive pupil testing sequences.
关键词： pupil light reflex,intrinsically photosensitive retinal ganglion cells (ipRGCs),melanopsin,post-illumination pupil response
更新于2025-09-09 09:28:46
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Nanotechnology in Water and Wastewater Treatment || Photocatalytic Decolorization of Two Remazol Dyes Using TiO2 Impregnated Pumice Composite as Catalyst
摘要： This study, as a first attempt, aimed to evaluate photocatalytic decolorization of of two remazol dyes (blue and red) using TiO2 impregnated pumice composite catalyst. The SEM-EDX analysis showed that TiO2 nanoparticules were mostly impregnated on the pores of pumice with a ratio of 1.60% Ti. A 97.8% and 97.6% of color removal was achieved for RB and RR at pH 3, respectively, whereas those color removal percentages decreased to 57.4% and 53.9%, respectively, at pH 11 after 2 hours illumination. The color removal efficiencies of 97.8%, 82.7%, and 75.3% for RB dye and of 97.6%, 85.3%, and 84.0% for RR dye were observed after first, second, and third cycles reuse of the synthesized catalyst. Toxicity of photocatalytic treated samples of both dyes decreased below 50% after 90 and 120 minutes irradiation when they were diluted at 75%. This result indicate there is an urgent need to prolong the irradiation time and/or for increasing catalyst dose to completely remove toxicity in the undiluted samples.
关键词： TiO2 impregnated pumice composite,Remazol dyes,Photocatalytic decolorization,Toxicity,UV-A illumination
更新于2025-09-09 09:28:46
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[IEEE 2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - Bangalore (2018.7.10-2018.7.12)] 2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT) - A Novel Approach for Internet of Things Based Intelligent Lighting
摘要： Lighting contributes a sizeable share to energy wastage globally and so development of Internet of Things based smart lighting system is on the rise. The prevalent ambient smart lighting systems see limited use since they have not been developed with a generic perspective to be installed everywhere. This has not yet been possible because there are a lot of variable and static parameters involved in the functioning of the smart lighting system. Moreover there is a trade-off between user comfort and energy savings which the current systems have not realised. In this paper a new algorithm is proposed which considers the factor of user comfort which enables the resulting system to understand the user’s requirements. There are also various parameters such as Light Re?ectance Value, weather, average natural light etc. which affect illumination. In this paper a new smart lighting system is proposed which works intelligently by considering these parameters.
关键词： Internet of Things,Illumination Factors,User Comfort,Smart Lighting System
更新于2025-09-09 09:28:46
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Cancellation of Bessel beam side lobes for high-contrast light sheet microscopy
摘要： An ideal illumination for light sheet fluorescence microscopy entails both a localized and a propagation invariant optical field. Bessel beams and Airy beams satisfy these conditions, but their non-diffracting feature comes at the cost of the presence of high-energy side lobes that notably degrade the imaging contrast and induce photobleaching. Here, we demonstrate the use of a light droplet illumination whose side lobes are suppressed by interfering Bessel beams of specific k-vectors. Our droplet illumination readily achieves more than 50% extinction of the light distributed across the Bessel side lobes, providing a more efficient energy localization without loss in transverse resolution. In a standard light sheet fluorescence microscope, we demonstrate a two-fold contrast enhancement imaging micron-scale fluorescent beads. Results pave the way to new opportunities for rapid and deep in vivo observations of large-scale biological systems.
关键词： light sheet microscopy,Bessel beams,fluorescence imaging,droplet illumination,Airy beams
更新于2025-09-04 15:30:14
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Endoscopic image enhancement with noise suppression
摘要： Stereoscopic endoscopes have been used increasingly in minimally invasive surgery to visualise the organ surface and manipulate various surgical tools. However, insuf?cient and irregular light sources become major challenges for endoscopic surgery. Not only do these conditions hinder image processing algorithms, sometimes surgical tools are barely visible when operating within low-light regions. In addition, low-light regions have low signal-to-noise ratio and metrication artefacts due to quantisation errors. As a result, present image enhancement methods usually suffer from heavy noise ampli?cation in low-light regions. In this Letter, the authors propose an effective method for endoscopic image enhancement by identifying different illumination regions and designing the enhancement design criteria for desired image quality. Compared with existing image enhancement methods, the proposed method is able to enhance the low-light region while preventing noise ampli?cation during image enhancement process. The proposed method is tested with 200 images acquired by endoscopic surgeries. Computed results show that the proposed algorithm can outperform state-of-the-art algorithms for image enhancement, in terms of naturalness image quality evaluator and illumination index.
关键词： image quality,endoscopic image enhancement,noise suppression,minimally invasive surgery,illumination regions
更新于2025-09-04 15:30:14
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Recent Advances in 3D Structured Illumination Microscopy
摘要： In structured illumination microscopy (SIM) the sample under investigation is illuminated using a structured illumination (SI) pattern. This SI pattern encodes high spatial frequencies of fine features within the sample, which usually are not transferred by the conventional three-dimensional (3D) optical transfer function (OTF) of the imaging system and fills the missing cone of frequencies in the OTF for better discrimination of the out-of- focus light. Thereby, SIM provides super-resolution (SR) performance beyond the diffraction limit and optical- sectioning (OS) capability with the use of data post-processing approaches. 3D structured patterns that include lateral and axial variations in the illumination have attracted more attention recently as they provide OS and SR enhancement in three dimensions. In this paper, we review recent implementations in generating a 3D SI pattern with tunable modulation frequency (independently of both the objective lens and the wavelength used) using a Fresnel biprism or a Wollaston prism. From the raw SIM images, final SIM images with simultaneous OS and SR are retrieved without artifacts due to coherent noise.
关键词： Fresnel biprism,Wollaston prism,structured illumination design,super-resolution,tunable frequency,three-dimensional microscopy
更新于2025-09-04 15:30:14
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Perception of light source distance from shading patterns
摘要： Varying the distance of a light source from an object alters both the intensity and spatial distribution of surface shading patterns. We tested whether observers can use such cues to infer light source distance. Participants viewed stereoscopic renderings of rough objects with diffuse and glossy surfaces, which were illuminated by a point source at a range of distances. In one task, they adjusted the position of a small probe dot in three dimensions to report the apparent location of the light in the scene. In a second task, they adjusted the shading on one object (by moving an invisible light source) until it appeared to be illuminated from the same distance as another object. Participants’ responses increased linearly with the true light source distance, suggesting that they have clear intuitions about how light source distance affects shading patterns for a variety of different surfaces. However, there were also systematic errors: Subjects overestimated light source distance in the probe adjustment task, and in both experiments, roughness and glossiness affected responses. We find the pattern of results is predicted surprisingly well by a simplistic model based only on the area of the image that exceeds a certain intensity threshold. Thus, although subjects can report light source distance, they may rely on simple—sometimes erroneous—heuristics to do so.
关键词： lighting,reflectance,gloss,roughness,light source,illumination,material perception
更新于2025-09-04 15:30:14
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Characterization of neurite dystrophy after trauma by high speed structured illumination microscopy and lattice light sheet microscopy
摘要： Background: Unbiased screening studies have repeatedly identified actin-related proteins as one of the families of proteins most influenced by neurotrauma. Nevertheless, the status quo model of cytoskeletal reorganization after neurotrauma excludes actin and incorporates only changes in microtubules and intermediate filaments. Actin is excluded in part because it is difficult to image with conventional techniques. However, recent innovations in fluorescent microscopy provide an opportunity to image the actin cytoskeleton at super-resolution resolution in living cells. This study applied these innovations to an in vitro model of neurotrauma. New method: New methods are introduced for traumatizing neurons before imaging them with high speed structured illumination microscopy or lattice light sheet microscopy. Also, methods for analyzing structured illumination microscopy images to quantify post-traumatic neurite dystrophy are presented. Results: Human induced pluripotent stem cell-derived neurons exhibited actin organization typical of immature neurons. Neurite dystrophy increased after trauma but was not influenced by jasplakinolide treatment. The F-actin content of dystrophies varied greatly from one dystrophy to another. Comparison with existing methods: In contrast to fixation dependent methods, these methods capture the evolution of the actin cytoskeleton over time in a living cell. In contrast to prior methods based on counting dystrophies, this quantification scheme parameterizes the severity of a given dystrophy as it evolves from a local swelling to an almost-perfect spheroid that threatens to transect the neurite. Conclusions: These methods can be used to investigate genetic factors and therapeutic interventions that modulate the course of neurite dystrophy after trauma.
关键词： Traumatic brain injury,Dystrophy,Structured illumination microscopy,Human induced pluripotent stem cell derived neurons,Lattice light sheet microscopy
更新于2025-09-04 15:30:14
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Single Sample Face Recognition under Varying Illumination via QRCP Decomposition
摘要： In this paper, we present a novel high-frequency facial feature and a high-frequency based sparse representation classification to tackle single sample face recognition (SSFR) under varying illumination. Firstly, we propose the assumption that QRCP bases can represent intrinsic face surface features with different frequencies, and their corresponding energy coefficients describe illumination intensities. Based on this assumption, we take QRCP bases with corresponding weighting coefficients (i.e. the major components of energy coefficients) to develop the high-frequency facial feature of the face image, which is named as QRCP-face. The normalized QRCP-face (NQRCP-face) is constructed to further constraint illumination effects by normalizing the weighting coefficients of QRCP-face. Moreover, we propose the adaptive QRCP-face (AQRCP-face) that assigns a special parameter to NQRCP-face via the illumination level estimated by the weighting coefficients. Secondly, we consider that the differences of pixel images cannot model the intra-class variations of generic faces with illumination variations, and the specific identification information of the generic face is redundant for the current SSFR with generic learning. To tackle above two issues, we develop a general high-frequency based sparse representation (GHSP) model. Two practical approaches separated high-frequency based sparse representation (SHSP) and unified high-frequency based sparse representation (UHSP) are developed. Finally, the performances of the proposed methods are verified on the Extended Yale B, CMU PIE, AR, LFW and our self-built Driver face databases. The experimental results indicate that the proposed methods outperform previous approaches for SSFR under varying illumination.
关键词： high-frequency based sparse representation,Illumination variation,QRCP-face,high-frequency facial feature
更新于2025-09-04 15:30:14