A structured light system simplifies three-dimensional reconstruction by illuminating a specially designed pattern to the target object, thereby generating a distinct texture on it for imaging and further processing. ...
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A structured light system simplifies three-dimensional reconstruction by illuminating a specially designed pattern to the target object, thereby generating a distinct texture on it for imaging and further processing. Success of the system hinges upon what features are to be coded in the projected pattern, extracted in the captured image, and matched between the projector's display panel and the camera's image plane. The codes have to be such that they are largely preserved in the image data upon illumination from the projector, reflection from the target object, and projective distortion in the imaging process. The features also need to be reliably extracted in the image domain. In this article, a two-dimensional pseudorandom pattern consisting of rhombic color elements is proposed, and the grid points between the pattern elements are chosen as the feature points. We describe how a type classification of the grid points plus the pseudorandomness of the projected pattern can equip each grid point with a unique label that is preserved in the captured image. We also present a grid point detector that extracts the grid points without the need of segmenting the pattern elements, and that localizes the grid points in subpixel accuracy. Extensive experiments are presented to illustrate that, with the proposed pattern feature definition and feature detector, more features points in higher accuracy can be reconstructed in comparison with the existing pseudorandomly encoded structured light systems. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3615649]
Palmprint has been widely studied as its high accuracy and low cost. Most of the previous studies are based on two dimensional (2D) image of the palmprint. However, 2D image can be easily forged, which will threaten t...
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ISBN:
(纸本)9781424427932
Palmprint has been widely studied as its high accuracy and low cost. Most of the previous studies are based on two dimensional (2D) image of the palmprint. However, 2D image can be easily forged, which will threaten the security of palmprint authentication system. Furthermore, 2D image can be easily affected by noise, such as scrabbling and dirty in the palm. To overcome these shortcomings, we develop a three dimensional (3D) palmprint identification system. The structured-light imaging technology is adopted to collect the 3D palmprint data, from which the stable Mean Curvature Image (MCI) is extracted. Then the Competitive coding (CompCode) technique is used to code the 3D palmprint pattern according the MCI. By using score level fusion of MCI and its CompCode, promising recognition performance is achieved on our established 3D palmprint database.
Steganography is a method of hiding data within a cover media so that other individuals fail to realize their existence. In this paper, a new approach for steganography in Arabic texts is proposed. The main idea is th...
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ISBN:
(纸本)9781424438075
Steganography is a method of hiding data within a cover media so that other individuals fail to realize their existence. In this paper, a new approach for steganography in Arabic texts is proposed. The main idea is that each Arabic word may have some characters which can be extended by 'Kashida'. The ranks 'locations' of such characters and the inserted Kashida, construct a coding method to represent a block of secret bits. Different scenarios have been proposed based on the maximum number of Kashida possible to be inserted per word. The approach was compared to some existing Arabic text steganography approaches in terms of capacity and security. It is shown that this proposed approach outperforms the others with interesting promising results.
By expanding communication, in some cases there is a need for hidden communication. Steganography is one of the methods used for hidden exchange of information. Steganography is a method to hide the information under ...
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ISBN:
(纸本)9781402087400
By expanding communication, in some cases there is a need for hidden communication. Steganography is one of the methods used for hidden exchange of information. Steganography is a method to hide the information under a cover media such as image or sound. In this paper a new method for Steganography in Persian and Arabic texts is presented. Here we use the special form of "La" word for hiding the data. This word is created by connecting "Lam" and "Alef" characters. For hiding bit 0 we use the normal form of word "La" ("(sic)") by inserting Arabic extension character between "Lam" and "Alef" characters. But for hiding bit I we use the special form of word "La" ("gamma") which has a unique code in Unicode standard texts. Its code is FEFB in Unicode hex notation. This method is not limited to electronic documents (E-documents) and also can be used on printed documents. This approach can be categorized under feature coding methods.
Based on feature coding mechanism, the association between the markup content and the solid model of design is researched and a method to markup 3D models visually is implemented. The members of a design group can vie...
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Based on feature coding mechanism, the association between the markup content and the solid model of design is researched and a method to markup 3D models visually is implemented. The members of a design group can view 3D models, make markups on the interesting aspects of the design and examine the markup content of other members. The approach can help to exchange the engineering information within the cooperative design group.
The dynamic and consistent information association among vtrious application activities in the full life cycle of a product is a key to the assurance of the cooperation among different application domains. In order to...
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The dynamic and consistent information association among vtrious application activities in the full life cycle of a product is a key to the assurance of the cooperation among different application domains. In order to establish and maintain the association, a design-process-based product association model was proposed. This model takes advantage of the generic naming mechanism, the private protocol for history-based form feature modeling, on which the Data Association Protocol is built. Hence the model can provide the way of constructing and maintaining the information linkage among different product developing stages naturally and dynamically while keeping the privacy of the feature coding. A case study illustrates the utilities of the model in the data linking between design model and process planning model.
Apparent motion (AM) was studied using the missing-fundamental square-wave grating, displaced discretely over time. At inter-stimulus (ISIs) greater than about 40 msec, AM was seen in the direction of displacement of ...
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Apparent motion (AM) was studied using the missing-fundamental square-wave grating, displaced discretely over time. At inter-stimulus (ISIs) greater than about 40 msec, AM was seen in the direction of displacement of the visible features of the pattern, while at shorter ISIs AM was seen in the reversed direction, following the displacement of the third harmonic spatial frequency component. This confirms (a) that the "long-range", feature-based process can bridge much greater time-gaps than the "short-range" motion sensors and (b) that the missing-fundamental pattern is a particularly useful tool for teasing the two processes apart.
This paper examines the psychological reality of feature representations. Given the non-cognitive linguistic and the low-level phonetic approaches, it is a priori an open question whether the psycholinguistic represen...
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This paper examines the psychological reality of feature representations. Given the non-cognitive linguistic and the low-level phonetic approaches, it is a priori an open question whether the psycholinguistic representation borrows from both, from either or from neither of these. As a test case, a point of divergence between phoneticians and linguists has been selected for scrutiny. While the former consider [f] and [v] to be labiodental fricatives, the latter regard them as underlying bilabials or simply labials. To determine if [f] and [v] behave psycholinguistically like bilabial or labiodental segments, the interactions between the fricatives at issue and the other phonemes are analyzed in two large corpora of slips of the tongue in English and German. The results indicate that [f] and [v] are indistinguisable from bilabials, that is, they are as likely to substitute for other bilabials and as unlikely to replace non-bilabials in the way that [p], [m] or [w] do. Three hypotheses are put forward in an attempt to come to grips with this finding. According to the bilabialness-only and the labialness-only hypotheses there is no node for labiodentalness in the processing network. The rival account starts from the assumption that features are represented as vectors in a space coordinate system. In this concept, there is a vector for bilabialness as well as one for labiodentalness. It is claimed that these vectors are closer to each other than their actual phonetic distance would imply. There is less empirical support for the vector hypothesis than for the bilabialness-only one. It is concluded that phonetic and psycholinguistic feature representations need not match.
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