15 resultados para Face representation and recognition

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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Subspace learning is the process of finding a proper feature subspace and then projecting high-dimensional data onto the learned low-dimensional subspace. The projection operation requires many floating-point multiplications and additions, which makes the projection process computationally expensive. To tackle this problem, this paper proposes two simple-but-effective fast subspace learning and image projection methods, fast Haar transform (FHT) based principal component analysis and FHT based spectral regression discriminant analysis. The advantages of these two methods result from employing both the FHT for subspace learning and the integral vector for feature extraction. Experimental results on three face databases demonstrated their effectiveness and efficiency.

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Ultrafast temporal pattern generation and recognition with femtosecond laser technology is presented, analyzed, and experimentally implemented. Ultrafast temporal pattern generation and recognition are realized by taking advantage of two well-known techniques: the space-time conversion technique and the ultrafast pulse measurement technique. Here the temporal pattern for the designed multiple pulses, optimized with a preassumed Gaussian spectral distribution of an ultrashort pulse, is described. With the simulation of a Gaussian spectral distribution, we realize that the uniformity of the generated multiple ultrafast temporal pulses is relevant to the repeated number of modulation periods in the mask in the spectral plane. Moreover, the change of Gaussian spectral phases with the wavelengths in the modulated phase plate is considered. Experiments of ultrafast temporal pattern recognition by the frequency-resolved optical gating (FROG) characterization technique are also given. (C) 2004 Society of Photo-Optical Instrumentation Engineers.

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Analytic propagation expressions of pulsed Gaussian beam are deduced by using complex amplitude envelope representation and complex analytic signal representation. Numerical calculations are given to illustrate the differences between them. The results show that the major difference between them is that there exists singularity in the beam obtained by using complex amplitude envelope representation. It is also found that singularity presents near propagation axis in the case of broadband and locates far from propagation axis in the case of narrowband. The critical condition to determine what representation should be adopted in studying pulsed Gaussian beam is also given. (C) 2004 Elsevier B.V. All rights reserved.

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Pen-based user interface has become a hot research field in recent years. Pen gesture plays an important role in Pen-based user interfaces. But it’s difficult for UI designers to design, and for users to learn and use. In this purpose, we performed a research on user-centered design and recognition pen gestures. We performed a survey of 100 pen gestures in twelve famous pen-bases systems to find problems of pen gestures currently used. And we conducted a questionnaire to evaluate the matching degree between commands and pen gestures to discover the characteristics that a good pen gestures should have. Then cognition theories were applied to analyze the advantages of those characteristics in helping improving the learnability of pen gestures. From these, we analyzed the pen gesture recognition effect and presented some improvements on features selection in recognition algorithm of pen gestures. Finally we used a couple of psychology experiments to evaluate twelve pen gestures designed based on the research. It shows those gestures is better for user to learn and use. Research results of this paper can be used for designer as a primary principle to design pen gestures in pen-based systems.

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In this article, graphical representations of DNA primary sequences were generated. Topological indices and molecular connectivity indices were calculated and used for the comparison of similarities among eight different DNA segments. The satisfactory results were achieved by this analysis.

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In this paper, we firstly give the nature of 'hypersausages', study its structure and training of the network, then discuss the nature of it by way of experimenting with ORL face database, and finally, verify its unsurpassable advantages compared with other means.

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In this paper, we firstly give the nature of 'hypersausages', study its structure and training of the network, then discuss the nature of it by way of experimenting with ORL face database, and finally, verify its unsurpassable advantages compared with other means.

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Concept maps are an important tool to knowledge organization,representation, and sharing. Most current concept map tools do not provide full support for hand-drawn concept map creation and manipulation, largely due to the lack of methods to recognize hand-drawn concept maps. This paper proposes a structure recognition method. Our algorithm can extract node blocks and link blocks of a hand-drawn concept map by combining dynamic programming and graph partitioning and then build a concept-map structure by relating extracted nodes and links. We also introduce structure-based intelligent manipulation technique of hand-drawn concept maps. Evaluation shows that our method has high structure recognition accuracy in real time, and the intelligent manipulation technique is efficient and effective.

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In recognition-based user interface, users’ satisfaction is determined not only by recognition accuracy but also by effort to correct recognition errors. In this paper, we introduce a crossmodal error correction technique, which allows users to correct errors of Chinese handwriting recognition by speech. The focus of the paper is a multimodal fusion algorithm supporting the crossmodal error correction. By fusing handwriting and speech recognition, the algorithm can correct errors in both character extraction and recognition of handwriting. The experimental result indicates that the algorithm is effective and efficient. Moreover, the evaluation also shows the correction technique can help users to correct errors in handwriting recognition more efficiently than the other two error correction techniques.

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In most contemporary optics courses, Gaussian beams are demonstrated in the form of propagation along one coordinate axis. This is referred to as the conventional representation and is in fact a special form. In this paper, we derive the general representation of a Gaussian beam propagating obliquely to the coordinate axis, by performing a coordinate rotation transformation on the conventional representation. When doing so on the beam parameters, a restrictive condition has to be taken into account. Without this condition, the expressions for the beam parameters after the rotation are not consistent with the conventional ones.

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A unified theory is advanced to describe both the lateral Goos-Hanchen (GH) effect and the transverse Imbert-Fedorov (IF) effect, through representing the vector angular spectrum of a three-dimensional light beam in terms of a two-form angular spectrum consisting of its two orthogonal polarized components. From this theory, the quantization characteristics of the GH and IF displacements are obtained, and the Artmann formula for the GH displacement is derived. It is found that the eigenstates of the GH displacement are the two orthogonal linear polarizations in this two-form representation, and the eigenstates of the IF displacement are the two orthogonal circular polarizations. The theoretical predictions are found to be in agreement with recent experimental results.

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The study of associations between two biomolecules is the key to understanding molecular function and recognition. Molecular function is often thought to be determined by underlying structures. Here, combining a single-molecule study of protein binding with an energy-landscape-inspired microscopic model, we found strong evidence that biomolecular recognition is determined by flexibilities in addition to structures. Our model is based on coarse-grained molecular dynamics on the residue level with the energy function biased toward the native binding structure ( the Go model). With our model, the underlying free-energy landscape of the binding can be explored. There are two distinct conformational states at the free-energy minimum, one with partial folding of CBD itself and significant interface binding of CBD to Cdc42, and the other with native folding of CBD itself and native interface binding of CBD to Cdc42. This shows that the binding process proceeds with a significant interface binding of CBD with Cdc42 first, without a complete folding of CBD itself, and that binding and folding are then coupled to reach the native binding state.

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Since 1970s, igneous reservoirs such as Shang741, Bin674 and Luol51 have been found in Jiyang depression, which are enrichment and heavy-producing. Showing good prospect of exploration and development, igneous reservoirs have been the main part of increasing reserves and production in Shengli oilfield. As fracture igneous reservoir being an extraordinary complex concealed reservoir and showing heavy heterogeneity in spatial distribution, the study of recognition, prediction, formation mechanism and the law of distribution of fracture is essential to develop the reservoir. Guided by multiple discipline theory such as sedimentology, geophysics, mineralogy, petroleum geology, structural geology and reservoir engineering, a set of theories and methods of recognition and prediction of fractured igneous rock reservoir are formed in this paper. Rock data, three-dimensional seismic data, log data, borehole log data, testing data and production data are combined in these methods by the means of computer. Based on the research of igneous rock petrography and reservoir formation mechanism, emphasized on the assessment and forecast of igneous rock reservoir, aimed at establishing a nonhomogeneity quantification model of fractured igneous rock reservoir, the creativity on the fracture recognition, prediction and formation mechanism are achieved. The research result is applied to Jiyang depression, suggestion of exploration and development for fractured igneous rock reservoir is supplied and some great achievement and favourable economic effect are achieved. The main achievements are gained as follows: 1. The main facies models of igneous rock reservoir in JiYang depression are summarized. Based on data and techniques of seism, well log and logging,started from the research of single well rock facies, proceeded by seismic and log facies research, from point to line and line to face, the regional igneous facies models are established. And hypabyssal intrusion allgovite facies model, explosion volcaniclastic rock facies model and overfall basaltic rocks facies model are the main facies models of igneous rock reservoir in JiYang depression. 2. Four nonhomogenous reservoir models of igneous reservoirs are established, which is the base of fracture prediction and recognition. According to characteristics of igneous petrology and spatial types of reservoir, igneous reservoirs of Jiyang depression are divided into four categories: fractured irruptive rock reservoir, fracture-pore thermocontact metamorphic rock and irruptive rock compound reservoir, pore volcanic debris cone reservoir and fracture-pore overfall basaltic rock reservoir. The spatial distribution of each model's reservoir has its features. And reservoirs can be divided into primary ones and secondary ones, whose mechanism of formation and laws of distribution are studied in this paper. 3. Eight geologic factors which dominate igneous reservoirs are presented. The eight geologic factors which dominates igneous reservoirs are igneous facies, epigenetic tectonics deformation, fracture motion, intensity of intrusive effect and adjoining-rock characters, thermo-contact metamorphic rock facies, specific volcano-tectonic position, magmatic cyclicity and epigenetic diagenetic evolution. The interaction of the eight factors forms the four types nonhomogenous reservoir models of igneous reservoirs in Jiyang depression. And igneous facies and fracture motion are the most important and primary factors. 4. Identification patterns of seismic, well log and logging facies of igneous rocks are established. Igneous rocks of Jiyang depression show typical reflecting features on seismic profile. Tabular reflection seismic facies, arc reflection seismic facies and hummocky or mushroom reflection seismic facies are the three main facies. Logging response features of basic basalt and diabase are shown as typical "three low and two high", which means low natural gamma value, low interval transit-time, low neutron porosity, high resistivity and high density. Volcaniclastic rocks show "two high and three low"-high neutron porosity, high interval transit-time, low density, low-resistance and low natural gamma value. Thermo-contact metamorphic rocks surrounding to diabase show "four high and two low" on log data, which is high natural gamma value, high self-potential anomaly, high neutron porosity, high interval transit-time and low density and low-resistance. Based on seismic, well log and logging data, spatial shape of Shang 741 igneous rock is described. 5. The methods of fracture prediction and recognition for fractured igneous reservoir are summarized. Adopting FMI image log and nuclear magnetic resonance log to quantitative analysis of fractured igneous reservoir and according to formation mechanism and shape of fracture, various fractures are recognized, such as high-angle fracture, low-angle fracture, vertical fracture, reticulated fracture, induced fracture, infilling fracture and corrosion vug. Shang 741 intrusive rock reservoir can be divided into pore-vug compound type, pore fracture type, micro-pore and micro-fracture type. Physical properties parameters of the reservoir are computed and single-well fracture model and reservoir parameters model are established. 6. Various comprehensive methods of fracture prediction and recognition for fractured igneous reservoir are put forward. Adopting three-element (igneous facies, fracture motion and rock bending) geologic comprehensive reservoir evaluation technique and deep-shallow unconventional laterolog constrained inversion technique, lateral prediction of fractured reservoir such as Shang 741 is taken and nonhomogeneity quantification models of reservoirs are established.

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A number of functional neuroimaging studies with skilled readers consistently showed activation to visual words in the left mid-fusiform cortex in occipitotemporal sulcus (LMFC-OTS). Neuropsychological studies also showed that lesions at left ventral occipitotemporal areas result in impairment in visual word processing. Based on these empirical observations and some theoretical speculations, a few researchers postulated that the LMFC-OTS is responsible for instant parallel and holistic extraction of the abstract representation of letter strings, and labeled this piece of cortex as “visual word form area” (VWFA). Nonetheless, functional neuroimaging studies alone is basically a correlative rather than causal approach, and lesions in the previous studies were typically not constrained within LMFC-OTS but also involving other brain regions beyond this area. Given these limitations, it remains unanswered for three fundamental questions: is LMFC-OTS necessary for visual word processing? is this functionally selective for visual word processing while unnecessary for processing of non-visual word stimuli? what are its function properties in visual word processing? This thesis aimed to address these questions through a series of neuropsychological, anatomical and functional MRI experiments in four patients with different degrees of impairments in the left fusiform gyrus. Necessity: Detailed analysis of anatomical brain images revealed that the four patients had differential foci of brain infarction. Specifically, the LMFC-OTS was damaged in one patient, while it remained intact in the other three. Neuropsychological experiments showed that the patient with lesions in the LMFC-OTS had severe impairments in reading aloud and recognizing Chinese characters, i.e., pure alexia. The patient with intact LMFC-OTS but information from the left visual field (LVF) was blocked due to lesions in the splenium of corpus callosum, showed impairment in Chinese characters recognition when the stimuli were presented in the LVF but not in the RVF, i.e. left hemialexia. In contrast, the other two patients with intact LMFC-OTS had normal function in processing Chinese characters. The fMRI experiments demonstrated that there was no significant activation to Chinese characters in the LMFC-OTS of the pure alexic patient and of the patient with left hemialexia when the stimuli were presented in the LVF. On the other hand, this patient, when Chinese characters were presented in right visual field, and the other two with intact LMFC-OTS had activation in the LMFC-OTS. These results together point to the necessity of the LMFC-OTS for Chinese character processing. Selectivity: We tested selectivity of the LMFC-OTS for visual word processing through systematically examining the patients’ ability for processing visual vs. auditory words, and word vs. non-word visual stimuli, such as faces, objects and colors. Results showed that the pure alexic patients could normally process auditory words (expression, understanding and repetition of orally presented words) and non-word visual stimuli (faces, objects, colors and numbers). Although the patient showed some impairments in naming faces, objects and colors, his performance scores were only slightly lower or not significantly different relative to those of the patients with intact LMFC-OTS. These data provide compelling evidence that the LMFC-OTS is not requisite for processing non-visual word stimuli, thus has selectivity for visual word processing. Functional properties: With tasks involving multiple levels and aspects of word processing, including Chinese character reading, phonological judgment, semantic judgment, identity judgment of abstract visual word representation, lexical decision, perceptual judgment of visual word appearance, and dictation, copying, voluntary writing, etc., we attempted to reveal the most critical dysfunction caused by damage in the LMFC-OTS, thus to clarify the most essential function of this region. Results showed that in addition to dysfunctions in Chinese character reading, phonological and semantic judgment, the patient with lesions at LMFC-OTS failed to judge correctly whether two characters (including compound and simple characters) with different surface features (e.g., different fonts, printed vs. handwritten vs. calligraphy styles, simplified characters vs. traditional characters, different orientations of strokes or whole characters) had the same abstract representation. The patient initially showed severe impairments in processing both simple characters and compound characters. He could only copy a compound character in a stroke-by-stroke manner, but not by character-by-character or even by radical-by-radical manners. During the recovery process, namely five months later, the patient could complete the abstract representation tasks of simple characters, but showed no improvement for compound characters. However, he then could copy compound characters in a radical-by-radical manner. Furthermore, it seems that the recovery of copying paralleled to that of judgment of abstract representation. These observations indicate that lesions of the LMFC-OTS in the pure alexic patients caused several damage in the ability of extracting the abstract representation from lower level units to higher level units, and the patient had especial difficulty to extract the abstract representation of whole character from its secondary units (e.g., radicals or single characters) and this ability was resistant to recover from impairment. Therefore, the LMFC-OTS appears to be responsible for the multilevel (particularly higher levels) abstract representations of visual word form. Successful extraction seems independent on access to phonological and semantic information, given the alexic patient showed severe impairments in reading aloud and semantic processing on simple characters while maintenance of intact judgment on their abstract representation. However, it is also possible that the interaction between the abstract representation and its related information e.g. phonological and semantic information was damaged as well in this patient. Taken together, we conclude that: 1) the LMFC-OTS is necessary for Chinese character processing, 2) it is selective for Chinese character processing, and 3) its critical function is to extract multiple levels of abstract representation of visual word and possibly to transmit it to phonological and semantic systems.

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Two major questions in this study are the development of children's representative drawing and the influence of semantic representation and image representation on it. Children aged from 3 and a half to 7 participated the experiments. Two-dimension and three-dimension displays were used in four experiments. The results show that: The development of children's representational drawing can be divided into stages. They become maturer in selecting the strategies of the representational drawing, which are different in nature across different ages. There is a development from feature processing to integrative processing in children's drawing. At the feature processing stage, the typological features are represented easily. No matter global or partial. They tend to use unconnected parts to represent, which is called the strategy of distributed representation, those displays without prominent features. In integrative processing stage, the features of two-dimension display are integrated according to its gestalt. And the features of three-dimension display are integrated by its prototypical view across the main axis of the display. Cubic representations were found in some of the children's drawings, but none of them can do it from a perspective view before 7 years old. The semantic processing of the display, both global and partial meaning, can influence the development of the representational drawing. The structural features of the display influence the development of drawing representation. Semantic principles and structural features influence the representational drawings together. For three-dimension display, the semantic face and structural face coexist and work together. Children's ability to draw the display according to the right perspective rather than the prototypical view increase along with them growing up.