- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Can Color and Motion Information Be Used to Disentangle the Influence of Multiple Light Sources on Gloss Perception?
摘要： Previous results suggest that the glossiness of a surface is systematically underestimated when adjacent highlights from different light sources overlap to such an extent that they appear as a single, expanded highlight. Here we investigated how the availability of color- and motion-induced information, which may help to unravel such merged highlights, affects gloss constancy. We used images of computer-generated scenes where a complex 3D object made of glossy material was illuminated by three point light sources, which had varying distances to each other. The point lights were either all achromatic or they differed clearly in their color and the test object was either presented statically or rotating. The subjects had to adjust the smoothness of a match object illuminated by a single achromatic point light so that it appeared to have the same glossiness as the test object. The results show that color information contributes to gloss constancy in this situation: If it was available, the perceived glossiness remained almost invariant with changes in the degree of overlap between the highlights. This suggests that highlights of different color are processed separately. Motion information had no such effect but only led to a general increase in perceived glossiness.
关键词： color,gloss perception,motion,surfaces/materials,gloss constancy,light
更新于2025-09-11 14:15:04
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The Cambridge History of Science || Greek Optics
摘要： Although it can be fairly said that, as a science in the modern sense, Greek optics had its wellsprings in ray theory, three caveats are in order. First, the goal of Greek optics was to explain vision, not the physics of light, so the classical ray represented a path for sight, not light. On that account, second, Greek optics must be evaluated within the broader context of concurrent epistemological thought. Finally, the dearth of contemporaneous sources makes it difficult to trace the development of Greek optics with any confidence. These caveats in mind, we shall begin with an overview of the evolution of ray theory from its presumed beginnings around 400 bce to its culmination in the later second century ce. Next, we shall discuss various models of visual perception formulated over roughly the same period, taking into account underlying physical, physiological, and psychological issues. We shall then narrow our focus upon mathematical optics. The resulting account will reflect the tripartite analytic structure that evolved over the period between Euclid (ca. 300 bce) and Ptolemy (ca. 160 ce). Accordingly, we shall examine the development of optics proper first (involving unimpeded visual radiation), then of catoptrics (involving fully broken or reflected visual radiation), and, last, of dioptrics (involving partially broken or refracted visual radiation).
关键词： Ptolemy,ray theory,mathematical optics,Greek optics,Euclid,visual perception
更新于2025-09-10 09:29:36
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Fabric Structures in Architecture || Lighting and the visual environment in architectural fabric structures
摘要： Human activities are closely linked to light; we cannot live without it. Daylight affects every part of our lives, and it makes life possible on earth. Light allows us to see, to know where we are and what lies around us. Light models the physical world to enhance visual perception and to help us negotiate around the natural and artificially made environment. Daylight is the source of energy that drives the growth and activity of all living organisms, and it is also essential to sustaining life by maintaining our biological rhythms and hormonal distribution.
关键词： Visual Environment,Architectural Fabric Structures,Lighting,Daylight,Visual Perception
更新于2025-09-10 09:29:36
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Simulation of visual perception and learning with a retinal prosthesis
摘要： The nature of artificial vision with a retinal prosthesis, and the degree to which the brain can adapt to the unnatural input from such a device, are poorly understood. Therefore, the development of current and future devices may be aided by theory and simulations that help to infer and understand what prosthesis patients see. A biologically-informed, extensible computational framework is presented here to predict visual perception and the potential effect of learning with a subretinal prosthesis. The framework relies on optimal linear reconstruction of the stimulus from retinal responses to infer the visual information available to the patient. A simulation of the physiological optics of the eye and light responses of the major retinal neurons was used to calculate the optimal linear transformation for reconstructing natural images from retinal activity. The result was then used to reconstruct the visual stimulus during the artificial activation expected from a subretinal prosthesis in a degenerated retina, as a proxy for inferred visual perception. Several simple observations reveal the potential utility of such a simulation framework. The inferred perception obtained with prosthesis activation was substantially degraded compared to the inferred perception obtained with normal retinal responses, as expected given the limited resolution and lack of cell type specificity of the prosthesis. Consistent with clinical findings and the importance of cell type specificity, reconstruction using only ON cells, and not OFF cells, was substantially more accurate. Finally, when reconstruction was re-optimized for prosthesis stimulation, simulating the greatest potential for learning by the patient, the accuracy of inferred perception was much closer to that of healthy vision. The reconstruction approach thus provides a more complete method for exploring the potential for treating blindness with retinal prostheses than has been available previously. It may also be useful for interpreting patient data in clinical trials, and for improving prosthesis design.
关键词： vision,neuroengineering,sensory processing,Retina,perception,neural code,learning,prosthesis,neural interfaces
更新于2025-09-10 09:29:36
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Detection of bodies in maritime rescue operations using unmanned aerial vehicles with multispectral cameras
摘要： In this study, we use unmanned aerial vehicles equipped with multispectral cameras to search for bodies in maritime rescue operations. A series of flights were performed in open‐water scenarios in the northwest of Spain, using a certified aquatic rescue dummy in dangerous areas and real people when the weather conditions allowed it. The multispectral images were aligned and used to train a convolutional neural network for body detection. An exhaustive evaluation was performed to assess the best combination of spectral channels for this task. Three approaches based on a MobileNet topology were evaluated, using (a) the full image, (b) a sliding window, and (c) a precise localization method. The first method classifies an input image as containing a body or not, the second uses a sliding window to yield a class for each subimage, and the third uses transposed convolutions returning a binary output in which the body pixels are marked. In all cases, the MobileNet architecture was modified by adding custom layers and preprocessing the input to align the multispectral camera channels. Evaluation shows that the proposed methods yield reliable results, obtaining the best classification performance when combining green, red‐edge, and near‐infrared channels. We conclude that the precise localization approach is the most suitable method, obtaining a similar accuracy as the sliding window but achieving a spatial localization close to 1 m. The presented system is about to be implemented for real maritime rescue operations carried out by Babcock Mission Critical Services Spain.
关键词： environmental monitoring,aerial robotics,learning,emergency response,perception
更新于2025-09-10 09:29:36
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[IEEE 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Trebic, Czech Republic (2018.9.18-2018.9.20)] 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Public Lighting, Public Health
摘要： Impact of artificial light at night on sleep and health of humans and other living species is discussed among scientists. This paper analyses the properties of several commercially available light sources with regards to their effects on wildlife, human sleep, and health. A novel, environmentally considerate LED light source is introduced. Further, integration of this light source into the pilot biodynamic street lighting system is described. Based on the season and time of day, a control system changes the spectral composition of the light in lighting without compromising on safety, psychological needs or energy savings.
关键词： advanced control system,spectral power distribution,light at night,LED,biodynamic lighting,non-image forming light perception,Circadian rhythm
更新于2025-09-10 09:29:36
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[ACM Press the 11th International Symposium - Växjö, Sweden (2018.08.13-2018.08.15)] Proceedings of the 11th International Symposium on Visual Information Communication and Interaction - VINCI '18 - Contrast Enhancement Based on Viewing Distance
摘要： In this paper, we propose an image-space contrast enhancement method for color-encoded visualization. The contrast of an image is enhanced through a perceptually-guided approach that interfaces with the user with a single and intuitive parameter of the virtual viewing distance. To this end, we analyze a multiscale contrast model of the input image and test the visibility of bandpass images of all scales at a virtual viewing distance. By adapting weights of bandpass images with a threshold model of spatial vision, this image-based method enhances contrast to compensate for contrast loss caused by viewing the image at a certain distance. Relevant features in the color image can be further emphasized by the user using overcompensation. The method is efficient and can be integrated into any visualization tool as it is a generic image-based post-processing technique. Using highly diverse datasets, we show the usefulness of perception compensation across a wide range of typical visualizations.
关键词： Contrast,visualization,perception
更新于2025-09-10 09:29:36
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Scan, dwell, decide: Strategies for detecting abnormalities in diabetic retinopathy
摘要： Diabetic retinopathy (DR) is a disease which is widely diagnosed using (colour fundus) images. Efficiency and accuracy are critical in diagnosing DR as lack of timely intervention can lead to irreversible visual impairment. In this paper, we examine strategies for scrutinizing images which affect diagnostic performance of medical practitioners via an eye-tracking study. A total of 56 subjects with 0 to 18 years of experience participated in the study. Every subject was asked to detect DR from 40 images. The findings indicate that practitioners use mainly two types of strategies characterized by either higher dwell duration or longer track length. The main findings of the study are that higher dwell-based strategy led to higher average accuracy (> 85%) in diagnosis, irrespective of the expertise of practitioner; whereas, the average obtained accuracy with a long-track length-based strategy was dependent on the expertise of the practitioner. In the second part of the paper, we use the experimental findings to recommend a scanning strategy for fast and accurate diagnosis of DR that can be potentially used by image readers. This is derived by combining the eye-tracking gaze maps of medical experts in a novel manner based on a set of rules. This strategy requires scrutiny of images in a manner which is consistent with spatial preferences found in human perception in general and in the domain of fundus images in particular. The Levenshtein distance-based assessment of gaze patterns also establish the effectiveness of the derived scanning pattern and is thus recommended for image readers.
关键词： eye-tracking,visual perception,diagnostic strategies,Diabetic retinopathy,medical imaging
更新于2025-09-10 09:29:36
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Blind Image Quality Assessment with Semantic Information
摘要： No-reference (NR) image quality assessment (IQA) aims to evaluate the quality of an image without reference image, which is greatly desired in the automatic visual signal processing system. Distortions degrade the visual contents and affect the semantics acquisition during the process of human perception. Although the existing methods evaluate the quality of images based on the structure, texture, or statistical characteristics, and deliver high quality prediction accuracy, they do not take the spatial semantics into account. From the perspective of human perception, distortions decrease the structural semantics that represent the structural information, and disturb the spatial semantics that describe the contents of images. Therefore, we attempt to measure the image quality by its degradation of semantics in an image. To extract the semantics of an image, a semantic network is proposed. The network contains convolutional neural networks (CNN) and Long Short-Term Memory (LSTM) that correspond to structural semantics and spatial semantics, respectively. CNN can be regarded as a coarse imitation of human visual mechanism to obtain the structural information, and LSTM can express the contents of an image. Then, by measuring the degradations of different semantics on images, a novel NR IQA is introduced. The proposed approach is evaluated on the databases of LIVE, CSIQ, TID2013, and LIVE multiply distorted database as well as LIVE in the wild image quality challenge database, and the results show superior performance to other state-of-the-art NR IQA methods. Furthermore, we explore the generalization capability of the proposed approach, and the experimental results indicate the proposed approach has a high robustness.
关键词： spatial semantics,No-reference image quality assessment,structural semantics,human perception,semantic network
更新于2025-09-09 09:28:46
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[IEEE 2018 IEEE International Symposium on Haptic, Audio and Visual Environments and Games (HAVE) - Dalian, China (2018.9.20-2018.9.21)] 2018 IEEE International Symposium on Haptic, Audio and Visual Environments and Games (HAVE) - No-Reference Quality Assessment for Stereoscopic 3D Images Based on Binocular Visual Perception
摘要： In this paper, we propose a blind/no-reference 3D image quality assessment scheme that utilizes binocular visual characteristics. The design of this scheme is motivated by studies on the perception of distorted stereoscopic images. Specifically, after the log-Gabor filter processing, the local amplitude, local phase and visual saliency are extracted from a stereopair and concatenated to form feature vectors. In addition, the binocular energy responses are also obtained as quality-predictive features. Experimental results show that the proposed scheme achieves superiority over other compared methods in terms of consistent alignment with human subjective judgments for stereoscopic images.
关键词： binocular visual perception,3D image quality assessment,no-reference
更新于2025-09-09 09:28:46