Documents disponibles écrits par cet auteur

Plane-based external camera calibration with accuracy measured by relative deflection angle / Chunhui Cui in Signal processing. Image communication, Vol. 25 N° 3 (02 ex.) (Mars 2010) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 25 N° 3 (02 ex.) (Mars 2010) . - pp. 224–234 Titre : Plane-based external camera calibration with accuracy measured by relative deflection angle Type de document : texte imprimé Auteurs : Chunhui Cui, Auteur ; King Ngi Ngan, Auteur Année de publication : 2010 Article en page(s) : pp. 224–234 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Camera  calibration  Homography  Accuracy  evaluation Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : In this paper, we present an efficient external calibration technique for a typical multi-camera system. The technique is very handy in practice using a simple planar pattern. Based on homography, three different pair-wise estimation algorithms are proposed to recover the rigid rotation and translation between neighboring cameras. By registering the accurate and reliable partial calibrated structures, the complete calibration of a multi-camera system can be accomplished. In order to evaluate and compare the calibration results for different camera setups, a novel accuracy metric is introduced based on the deflection angles of projection rays. Experimental results using both simulated and real data are presented to verify the validity and performance of the proposed method. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596509001350 [article] Plane-based external camera calibration with accuracy measured by relative deflection angle [texte imprimé] / Chunhui Cui, Auteur ; King Ngi Ngan, Auteur . - 2010 . - pp. 224–234. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 25 N° 3 (02 ex.) (Mars 2010) . - pp. 224–234 Mots-clés : Camera  calibration  Homography  Accuracy  evaluation Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : In this paper, we present an efficient external calibration technique for a typical multi-camera system. The technique is very handy in practice using a simple planar pattern. Based on homography, three different pair-wise estimation algorithms are proposed to recover the rigid rotation and translation between neighboring cameras. By registering the accurate and reliable partial calibrated structures, the complete calibration of a multi-camera system can be accomplished. In order to evaluate and compare the calibration results for different camera setups, a novel accuracy metric is introduced based on the deflection angles of projection rays. Experimental results using both simulated and real data are presented to verify the validity and performance of the proposed method. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science/article/pii/S0923596509001350

Platform-independent MB-based AVS video standard implementation / Xin Jin in Signal processing. Image communication, Vol. 24 N° 4 (Avril 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 4 (Avril 2009) . - pp. 312-323 Titre : Platform-independent MB-based AVS video standard implementation Type de document : texte imprimé Auteurs : Xin Jin, Auteur ; Songnan Li, Auteur ; King Ngi Ngan, Auteur Article en page(s) : pp. 312-323 Note générale : Electronique Langues : Anglais (eng) Mots-clés : AVS  video  standard  MB-based  architecture  Frame-based  architecture  Embedded  video  codec  implementation  Video  coding Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : AVS1-P2 is the newest video standard of Audio Video coding Standard (AVS) workgroup of China, which provides close performance to H.264/AVC main profile with lower complexity. In this paper, a platform-independent software package with macroblock-based (MB-based) architecture is proposed to facilitate AVS video standard implementation on embedded system. Compared with the frame-based architecture, which is commonly utilized for PC platform oriented video applications, the MB-based decoder performs all of the decoding processes, except the high-level syntax parsing, in a set of MB-based buffers with adequate size for saving the information of the current MB and the neighboring reference MBs to minimize the on-chip memory and to save the time consumed in on-chip/off-chip data transfer. By modifying the data flow and decoding hierarchy, simulating the data transfer between the on-chip memory and the off-chip memory, and modularizing the buffer definition and management for low-level decoding kernels, the MB-based system architecture provides over 80% reduction in on-chip memory compared to the frame-based architecture when decoding 720p sequences. The storage complexity is also analyzed by referencing the performance evaluation of the MB-based decoder. The MB-based decoder implementation provides an efficient reference to facilitate development of AVS applications on embedded system. The complexity analysis provides rough storage complexity requirements for AVS video standard implementation and optimization. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] Platform-independent MB-based AVS video standard implementation [texte imprimé] / Xin Jin, Auteur ; Songnan Li, Auteur ; King Ngi Ngan, Auteur . - pp. 312-323. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 4 (Avril 2009) . - pp. 312-323 Mots-clés : AVS  video  standard  MB-based  architecture  Frame-based  architecture  Embedded  video  codec  implementation  Video  coding Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : AVS1-P2 is the newest video standard of Audio Video coding Standard (AVS) workgroup of China, which provides close performance to H.264/AVC main profile with lower complexity. In this paper, a platform-independent software package with macroblock-based (MB-based) architecture is proposed to facilitate AVS video standard implementation on embedded system. Compared with the frame-based architecture, which is commonly utilized for PC platform oriented video applications, the MB-based decoder performs all of the decoding processes, except the high-level syntax parsing, in a set of MB-based buffers with adequate size for saving the information of the current MB and the neighboring reference MBs to minimize the on-chip memory and to save the time consumed in on-chip/off-chip data transfer. By modifying the data flow and decoding hierarchy, simulating the data transfer between the on-chip memory and the off-chip memory, and modularizing the buffer definition and management for low-level decoding kernels, the MB-based system architecture provides over 80% reduction in on-chip memory compared to the frame-based architecture when decoding 720p sequences. The storage complexity is also analyzed by referencing the performance evaluation of the MB-based decoder. The MB-based decoder implementation provides an efficient reference to facilitate development of AVS applications on embedded system. The complexity analysis provides rough storage complexity requirements for AVS video standard implementation and optimization. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]

A two-pass rate control algorithm for H.264/AVC high definition video coding / Dongdong Zhang in Signal processing. Image communication, Vol. 24 N° 5 (Mai 2009) 

Public ISBD [article]  in Signal processing. Image communication > Vol. 24 N° 5 (Mai 2009) . - pp. 357-367 Titre : A two-pass rate control algorithm for H.264/AVC high definition video coding Type de document : texte imprimé Auteurs : Dongdong Zhang, Auteur ; King Ngi Ngan, Auteur ; Zhenzhong Chen, Auteur Article en page(s) : pp. 357-367 Note générale : Electronique Langues : Anglais (eng) Mots-clés : Two-pass  Rate  control  Constant  quality  High  definition  video  coding Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : In this paper, we propose a novel two-pass rate control algorithm to achieve constant quality for H.264/AVC high definition video coding. With the first-pass collected rate and distortion information and the built model of scene complexity, the encoder can determine the expected distortion which could be achieved in the second-pass encoding under the target bit rate. According to the built linear distortion-quantizer (D-Q) model, before encoding one frame, the quantization parameter can be solved to realize constant quality encoding. After encoding one frame, the model parameters will be updated with linear regression method to ensure the prediction accuracy of the quantization parameter of next encoded frame with the same coding type. In order to obtain the expected distortion of each frame under the target bit rate, a GOP-level bit allocation scheme is also designed to adjust the target bit rate of each GOP based on the scene complexity of the GOP in the second-pass encoding. In addition, the effect of scene change on the updating of D-Q model is considered. The model will be re-initialized at the scene change to minimize modeling error. The experimental results show that compared with the latest two-pass rate control algorithm, our proposed algorithm can significantly improve the bit control accuracy at comparable coding performance in terms of constant quality and average PSNR. On average, the improvement of bit control accuracy achieved about 90%. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...] [article] A two-pass rate control algorithm for H.264/AVC high definition video coding [texte imprimé] / Dongdong Zhang, Auteur ; King Ngi Ngan, Auteur ; Zhenzhong Chen, Auteur . - pp. 357-367. Electronique Langues : Anglais (eng) in Signal processing. Image communication > Vol. 24 N° 5 (Mai 2009) . - pp. 357-367 Mots-clés : Two-pass  Rate  control  Constant  quality  High  definition  video  coding Index. décimale : 621.382 Dispositifs électroniques utilisant les effets des corps solides. Dispositifs semi-conducteurs Résumé : In this paper, we propose a novel two-pass rate control algorithm to achieve constant quality for H.264/AVC high definition video coding. With the first-pass collected rate and distortion information and the built model of scene complexity, the encoder can determine the expected distortion which could be achieved in the second-pass encoding under the target bit rate. According to the built linear distortion-quantizer (D-Q) model, before encoding one frame, the quantization parameter can be solved to realize constant quality encoding. After encoding one frame, the model parameters will be updated with linear regression method to ensure the prediction accuracy of the quantization parameter of next encoded frame with the same coding type. In order to obtain the expected distortion of each frame under the target bit rate, a GOP-level bit allocation scheme is also designed to adjust the target bit rate of each GOP based on the scene complexity of the GOP in the second-pass encoding. In addition, the effect of scene change on the updating of D-Q model is considered. The model will be re-initialized at the scene change to minimize modeling error. The experimental results show that compared with the latest two-pass rate control algorithm, our proposed algorithm can significantly improve the bit control accuracy at comparable coding performance in terms of constant quality and average PSNR. On average, the improvement of bit control accuracy achieved about 90%. DEWEY : 361.382 ISSN : 0923-5965 En ligne : http://www.sciencedirect.com/science?_ob=PublicationURL&_tockey=%23TOC%235640%23 [...]