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A Volumetric Approach to Point Cloud Compression-Part I: Attribute Compression

IEEE TRANSACTIONS ON IMAGE PROCESSING 2020年 29卷 2203-2216页

作者： Chou, Philip A. Koroteev, Maxim Krivokuca, Maja Google Inc Seattle WA 98103 USA Imatrex Inc Moscow 121205 Russia INRIA Ctr Rech Rennes Bretagne Atlantique F-35042 Rennes France

Compression of point clouds has so far been confined to coding the positions of a discrete set of points in space and the attributes of those discrete points. We introduce an alternative approach based on volumetric functions that are functions defined not just on a finite set of points but throughout space. As in regression analysis, volumetric functions are continuous functions that are able to interpolate values on a finite set of points as linear combinations of continuous basis functions. Using a B-spline wavelet basis, we are able to code volumetric functions representing both geometry and attributes. Geometry compression is addressed in Part II of this paper, while attribute compression is addressed in Part I. Attributes are represented by a volumetric function whose coefficients can be regarded as a critically sampled orthonormal transform that generalizes the recent successful Region-Adaptive Hierarchical (or Haar) Transform to higher orders. Experimental results show that attribute compression using higher order volumetric functions is an improvement over the first-order functions used in the emerging MPEG point cloud compression standard.

关键词： Three-dimensional displays Image coding Geometry Transforms Octrees Splines (mathematics) Hilbert space Bezier volumes B-splines wavelets point cloud compression color coding attribute coding multiresolution representations graph signal processing counting measure

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color CONCEPT RETRIEVAL BY FREE color NAMING - IDENTIFICATION OF UP TO 30 colorS WITHOUT TRAINING

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DISPLAYS 1995年第2期16卷 69-77页

作者： DEREFELDT, G SWARTLING, T National Defence Research Establishment Department of Human Sciences FOA 53 PO Box 1165 S-581 11 Linköping Sweden

Recent neuroscientific findings concerning the relationship between the perceptive, cognitive and linguistic aspects of colour suggest that colour concept retrieval would be enhanced by free colour naming or by the use of natural associations between colour concepts and colour words. To test this hypothesis, we had subjects give their own free associations to a set of 35 colours presented on a display. The results suggest that subjects with normal colour vision are able to identify absolutely 30 colours or more without training if colours are well separated, basic colours are used and colour concepts and colour words are naturally associated.

关键词： FREE color NAMING color COGNITION CATEGORICAL color PERCEPTION BASIC colorS color coding VISUAL DISPLAYS NCS CIELUV

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Ultra-Large color Difference and Small Subtense

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color RESEARCH AND APPLICATION 2010年第1期35卷 4-17页

作者： Carter, Robert Huertas, Rafael Univ Granada Fac Ciencias Dept Opt E-18071 Granada Spain

color difference calculations are usually applied to match or tolerance of small differences between large (>2 degrees) visual fields. In contrast, we examine here the application of ultra-large color differences to enhance conspicuousness and discriminability of small (1 degrees subtense or smaller) visual targets, e.g., in visual information displays. We show that CIEDE2000, and color difference metrics based on the OSA Uniform color Space and CIECAM02 are superior to CIELAB and CIELUV. Considering gray scale only, we show that Whittle's JND metric of achromatic contrast is as good as L* for this purpose, while also modeling contrast polarity and "crispening." Furthermore, using this JND metric, we replicate Highnote's finding that elongation of small targets affects their apparent contrast. We discuss the perceived fading of color differences when targets become smaller, and suggest practical methods to mitigate the adverse effect on color conspicuousness and discriminability. (C) 2009 Wiley Periodicals, Inc. Cot Res Appl, 35, 4-17, 2010;Published online 17 November 2009 in Wiley InterScience (***). DOI 10.1002/col.20557

关键词： color difference color coding conspicuousness discriminability visual search aspect ratio contrast

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ULTRAVIOLET AS A COMPONENT OF FLOWER REFLECTIONS, AND THE color-PERCEPTION OF HYMENOPTERA

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VISION RESEARCH 1994年第11期34卷 1489-1508页

作者： CHITTKA, L SHMIDA, A TROJE, N MENZEL, R HEBREW UNIV JERUSALEM DEPT EVOLUT ECOLIL-91904 JERUSALEMISRAEL INST BIOL 1 D-79104 FREIBERGGERMANY

Based on the measurements of 1063 flower reflection spectra, we show that flower colours fall into distinct dusters in the colour space of a bee. It is demonstrated that this clustering is caused by a limited variability in the floral spectral reflectance curves. There are as few as 10 distinct types of such curves, five of which constitute 85% of all measurements. UV reflections are less frequent and always lower in intensity than reflections in other parts of the spectrum. A further cluster of colour loci is formed in the centre of the colour space. It contains the colour loci of green leaves, several other background materials and only very few flowers. We propose a system to classify the reflection functions of flowers, and a set of colour names for bee colours.

关键词： color coding color VISION FLOWER colorS HYMENOPTERA SIGNALS SPECTRAL REFLECTANCE ULTRAVIOLET

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Finding and Counting Tree-Like Subgraphs Using MapReduce

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IEEE TRANSACTIONS ON MULTI-SCALE COMPUTING SYSTEMS 2018年第3期4卷 217-230页

作者： Zhao, Zhao Chen, Langshi Avram, Mihai Li, Meng Wang, Guanying Butt, Ali Khan, Maleq Marathe, Madhav Qiu, Judy Vullikanti, Anil Virginia Tech Biocomplex Inst Network Dynam & Simulat Sci Lab Blacksburg VA 24061 USA Virginia Tech Dept Comp Sci Blacksburg VA 24061 USA Indiana Univ Dept Comp Sci Bloomington IN 47405 USA Google Inc Mountain View CA 94043 USA Texas A&M Univ Kingsville Dept Elect Engn & Comp Sci Kingsville TX 78363 USA Indiana Univ Intelligent Syst Engn Dept Bloomington IN 47405 USA

Several variants of the subgraph isomorphism problem, e.g., finding, counting, and estimating frequencies of subgraphs in networks arise in a number of real world applications, such as web analysis, disease diffusion prediction, and social network analysis. These problems are computationally challenging in having to scale to very large networks with millions of vertices. In this paper, we present SAHAD, a MapReduce algorithm for detecting and counting trees of bounded size using the elegant color coding technique developed by N. Alon et al. SAHAD is a randomized algorithm, and we show rigorous bounds on the approximation quality and the performance of it. SAHAD scales to very large networks comprising of 10(7) - 10(8) vertices and 10(8) - 10(9) edges and tree-like (acyclic) templates with up to 12 vertices. Further, we extend our results by implementing SAHAD in the Harp framework, which is more of a high performance computing environment. The new implementation gives 100x improvement in performance over the standard Hadoop implementation and achieves better performance than state-of-the-art MPI solutions on larger graphs.

关键词： Subgraph isomorphism color coding approximation algorithm MapReduce Hadoop harp

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Spectral response properties of higher visual neurons in Drosophila melanogaster

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JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY 2020年第2期206卷 217-232页

作者： Yonekura, Taro Yamauchi, Junji Morimoto, Takako Seki, Yoichi Tokyo Univ Pharm & Life Sci Sch Life Sci Lab Mol Neurosci & Neurol 1432-1 Horinouchi Hachioji Tokyo 1920392 Japan

The fruit fly Drosophila melanogaster can process chromatic information for true color vision and spectral preference. Spectral information is initially detected by a few distinct photoreceptor channels with different spectral sensitivities and is processed through the visual circuit. The neuroanatomical bases of the circuit are emerging. However, only little information is available in chromatic response properties of higher visual neurons from this important model organism. We used in vivo whole-cell patch-clamp recordings in response to monochromatic light stimuli ranging from 300 to 650 nm with 25-nm steps. We characterized the chromatic response of 33 higher visual neurons, including their general response type and their wavelength tuning. color-opponent-type responses that had been typically observed in primates and bees were not identified. Instead, the majority of neurons showed excitatory responses to broadband wavelengths. The UV (300-375 nm) and middle wavelength (425-575 nm) ranges could be separated at the population level owing to neurons that preferentially responded to a specific wavelength range. Our results provide a first mapping of chromatic information processing in higher visual neurons of D. melanogaster that is a suitable model for exploring how color-opponent neural mechanisms are implemented in the visual circuits.

关键词： color vision Optic lobe color opponency color coding Insect brain

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MORPHOLOGICAL CLASSIFICATION OF BIPOLAR CELLS OF THE PRIMATE RETINA

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EUROPEAN JOURNAL OF NEUROSCIENCE 1991年第11期3卷 1069-1088页

作者： BOYCOTT, BB WASSLE, H MAX PLANCK INST HIRNFORSCH DEUTSCHORDENSTR 46 W-6000 FRANKFURT 71 GERMANY UNITED MED & DENT SCH DIV ANAT & CELL BIOL LONDON SE1 9RT ENGLAND

Bipolar cells were studied in Golgi-Colonnier-stained whole mounts of macaque monkey retinae. A piece of retina, at 6-7 mm eccentricity, was particularly well stained for the analysis of the different bipolar cell types. Many midget bipolar cells were encountered and the dichotomy into flat and invaginating midget bipolars was confirmed. Six types of diffuse cone bipolar cell are distinguished. They differ in their dendritic branching pattern, in the number of cones contacted-usually between five and ten-and in the shape and branching level of their axons. The size, shape and stratification of the axons were found to be the most reliable distinguishing features for classifying diffuse cone bipolar cells. The stratification of the axons in the inner plexiform layer (IPL), whether closer to the amacrine or ganglion cells, was used to name diffuse cone bipolar cells in the order DB1 to DB6. Blue cone and rod bipolar cells were confirmed as distinct types. Axon terminals of diffuse cone bipolars were found to tile their sublamina of the IPL in a territorial manner. From this the density of each type could be estimated, and it is shown that a single cone is likely to be in contact with as many as 15 individual diffuse bipolar cells, as well as two midget bipolars. The diffuse bipolar cells observed contact all the cone pedicles in their dendritic fields. It is, therefore, unlikely that they carry a chromatic signal into the inner retina. The presence of many midget bipolar cells, which make contact with one cone pedicle only, suggests that midget bipolars provide chromatic input to ganglion cells in peripheral retina as well as in the fovea. The data show that the P- and M-cell pathways of the primate visual system are, to a significant extent, already anatomically discrete at the photoreceptor synapse.

关键词： BIPOLAR CELLS GOLGI STAINING CONE SELECTIVITY color coding RHESUS MONKEY

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color DISPLAY IN ULTRASONOGRAPHY

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ULTRASOUND IN MEDICINE AND BIOLOGY 1983年第4期9卷 331-345页

作者： PIZER, SM ZIMMERMAN, JB UNIV N CAROLINA DEPT RADIOLCHAPEL HILLNC 27514

color display is useful in medical ultrasonography to increase sensitivity to contrast, to improve quantitative comparability between image regions, and to allow multiparameter display. In its first section this paper expands upon these objectives, sets forth the concepts of color definition, and discusses the criteria that should be used to select a pseudocolor display scale. The second section surveys the published work applying color display in ultrasonography, and the final section presents some of our recent results on (1) producing continuous pseudocolor scales with a natural order and with the property that equal changes in driving signal produce equally perceptible changes along the pseudocolor scale; and (2) applying these scales to ultrasound images.

关键词： color color coding Ultrasonics Grey scale

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EYE-MOVEMENT BEHAVIOR VIEWING color-CODED AND MONOCHROME AVIONIC DISPLAYS

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ERGONOMICS 1994年第11期37卷 1871-1884页

作者： HUGHES, PK CREED, DJ DEF SCI & TECHNOL ORG AERONAUT & MARITIME RES LAB506 LORIMER STFISHERMENS BENDMELBOURNEVIC 3207AUSTRALIA

This paper reports on two experiments in which subjects' eye movement behaviour was monitored while they searched for target information in colour coded and monochrome horizontal situation indicator (HSI) displays. The first experiment required subjects to locate and report alphanumeric information associated with the active waypoint on the displayed flightpath. Initial fixations in the display were more accurately directed to the target information when it was redundantly colour coded compared with when it was coded by shape and relative positional codes. Fewer fixations and a shorter time were required to locate the colour coded target and verbally report the relevant information. The time advantage of colour coded displays compared with monochrome displays was greatest for visually cluttered displays. In the second study there was no advantage of a coloured display when the task was to count all the displayed waypoint symbols on the flight path. The lack of any benefit for colour coding was a result of waypoint symbols having strong positional predictability due to their relationship to the displayed flightpath in both the colour and monochrome displays. The implication from these results is that colour coded information confers an advantage over a spatial code for targets at unknown spatial location but less benefit when target location can be predicted by other visual cues.

关键词： color coding EYE MOVEMENT VISUAL DISPLAY AVIATION

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CARTscans: A tool for visualizing complex models

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JOURNAL OF COMPUTATIONAL AND GRAPHICAL STATISTICS 2004年第4期13卷 807-825页

作者： Nason, M Emerson, S LeBlanc, M NIAID Biostat Res Branch Bethesda MD 20892 USA Univ Washington Dept Biostat Seattle WA 98195 USA

We present CARTscans, a graphical tool that displays predicted values across. a four-dimensional subspace. We show how these plots are useful for understanding the structure and relationships between variables in a wide variety of models. including (but not limited to) regression trees, ensembles of trees, and linear regressions with varving degrees of interactions. In addition, the common visualization framework allows diverse complex models to be visually compared in a way that illuminates the similarities and differences in the underlying methods, facilitates the choice of a particular model structure, and provided a useful check for implausible predictions of future observations in regions With little or no data.

关键词： bagging boosting classification and regression trees color coding graphics linear regression random forests visualization

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