An operational rate control (RC) scheme based on two-stage encoding is studied in this research, where frame-layer rate control with a constant bit rate to achieve constant video quality is examined. In the first enco...
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An operational rate control (RC) scheme based on two-stage encoding is studied in this research, where frame-layer rate control with a constant bit rate to achieve constant video quality is examined. In the first encoding stage, the R-D optimized mode decision and its associated motion estimation (RDO) as well as DCT/Q, IQ/IDCT and entropy coding are performed for all macroblocks (MBs) for a target frame using an initial quantization parameter (QP), which is the QP of its previous frame. In the second encoding stage, the residual signal from the first stage is encoded using several QP values around the initial QP. Given the target bits and distortion for the current frame, the residual signal is finally encoded using the QP determined by comparing target bits and distortion with actual bits and distortion. To reduce the additional coding complexity of the two-stage encoding, upper and lower bounds around target bits and distortion are employed to reduce the number of encoding required in the second stage. Experimental results are given to show the superior performance of two proposed rate control algorithms, where one targets at the constant bit rate while the other at constant quality.
A novel integrated multi-camera video-sensor (panoramic scene analysis - PSA) system is proposed for surveillance applications. In the proposed set-tip, an omnidirectional imaging device is used in conjunction with a ...
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A novel integrated multi-camera video-sensor (panoramic scene analysis - PSA) system is proposed for surveillance applications. In the proposed set-tip, an omnidirectional imaging device is used in conjunction with a pan tilt zoom (PTZ) camera leading to an innovative kind of sensor that is able to automatically track at a higher zoom level any moving object within the guarded area. In particular. the catadioptric sensor is calibrated and used it order to track every single moving object within its 360 degree field of view. Omnidirectional image portions are eventually rectified and pan, tilt and zoom parameters of the moving camera are automatically adjusted by the system in order to track detected object. In addition a co-operative strategy was developed for the selection of the object to be tracked by the PTZ sensor in the case of multiple targets.
Computing power at low cost, highly accurate 2D, 3D data acquisition systems, advanced methods of 2D, 3D signalprocessing, images synthesis, artificial intelligence and huge data base management utilities are the bas...
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ISBN:
(纸本)142440049X
Computing power at low cost, highly accurate 2D, 3D data acquisition systems, advanced methods of 2D, 3D signalprocessing, images synthesis, artificial intelligence and huge data base management utilities are the basic tools that can be used for development of dedicated systems that can help the work of art historians and archaeologists. In this paper we describe the application of some of these techniques in the domain of archaeology through two different applications: the reconstruction of complete archaeological sites and the reconstruction of broken objects from their fragments. Both applications are illustrated with concrete examples: the reconstruction of a necropolis in Itanos (Crete) and a Gallo-Roman sanctuary in Blicquy (Belgium) and the partial reconstruction of a fragmented stone sculpture from the church of Saints Michel-et-Gudule in Brussels (Belgium).
In this work an-image based photoplethysmography (PPG) system is developed and tested against a conventional finger-based system as commonly used in clinical practise. A PPG is essentially an optical instrument consis...
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ISBN:
(纸本)0819458082
In this work an-image based photoplethysmography (PPG) system is developed and tested against a conventional finger-based system as commonly used in clinical practise. A PPG is essentially an optical instrument consisting of a near infrared (NIR) source and detector that is capable of tracking blood flow changes in body tissue. When used with a number of wavelengths in the NIR band blood oxygenation changes as well as other blood chemical signatures can be ascertained yielding a very useful device in the clinical realm. Conventionally such a device requires direct contact with the tissue under investigation which eliminates the possibility of its use for applications like wound management where the tissue oxygenation measurement could be extremely useful. To circumnavigate this shortcoming we have developed a CMOS camera-based system, which can successfully extract the PPG signal without contact with the tissue under investigation. A comparison of our results with conventional techniques has yielded excellent results.
The best basis paradigm is a lower cost alternative to the principal component analysis (PCA) for feature extraction in pattern recognition applications. Its main idea is to build a collection of bases and search for ...
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ISBN:
(纸本)0819456454
The best basis paradigm is a lower cost alternative to the principal component analysis (PCA) for feature extraction in pattern recognition applications. Its main idea is to build a collection of bases and search for the best one in terms of e.g. best class separation. Recently, fast best basis search algorithms have been generalized for anisotropic wavelet packet bases. Anisotropy is preferable for 2-D objects since it helps capturing local image features in a better way. In this contribution, the best anisotropic basis search framework is applied to the problem of recognition of characters captured from gray-scale pictures of car license plates. The goals are to simplify the classifier and to avoid a preliminary binarization stage by extracting features directly from the gray-scale images. The collection of bases is formed by anisotropic wavelet packets. The search algorithm seeks for a basis providing the lowest-dimensional data representation preserving the inter-class separability for given training data set, measured as Euclidean distance between class centroids. The relationship between the feature extractor and classifier complexity is clarified by training neural networks for different local bases. The proposed methodology shows its superiority to PCA as it yields equal and even lower classification error rate with considerably reduced computational costs.
We describe in this paper the building of a vision sensor able to provide video capture and the associated global motion between two consecutive frames. Our objective is to propose embedded solutions for mobile applic...
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ISBN:
(纸本)354029032X
We describe in this paper the building of a vision sensor able to provide video capture and the associated global motion between two consecutive frames. Our objective is to propose embedded solutions for mobile applications. The global motion considered here is the one typically produced by handheld devices movement, which is required for our purpose of video stabilization. We extract this global motion from local motion measures at the periphery of the image acquisition area. Thanks to this peculiar and "task-oriented" configuration, the resulting system architecture can take advantage of CMOS focal plane processing capabilities without sacrificing the sensor fill factor. Our approach is currently implemented in a CMOS 0.13 mu m technology.
This paper reports the rate-distortion performance comparison of JPEG2000 with H.264/AVC Fidelity Range Extensions (FRExt) High Profile I-frame coding for high definition (HD) video sequences. This work can be conside...
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This paper reports the rate-distortion performance comparison of JPEG2000 with H.264/AVC Fidelity Range Extensions (FRExt) High Profile I-frame coding for high definition (HD) video sequences. This work can be considered as an extension of a similar earlier study involving H.264/AVC Main Profile [1]. Coding simulations are performed on a set of 720p and 1080p HD video sequences, which have been commonly used for H.264/AVC standardization work. As expected, our experimental results show that H.264/AVC FRExt I-frame coding offers consistent R-D performance gains (around 0.2 to 1 dB in peak signal-to-noise ratio) over JPEG2000 color image coding. However, similar to [1, 2], we have not considered scalability, computational complexity as well as other JPEG2000 features in this study.
Knowledge aided signalprocessing calls for the use of existing information such as digitized image maps to further suppress clutter in a typical radar detection operation. In the context of space based radar (SBR) ap...
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Projection pursuit (PP) is an interesting concept, which has been found in many applications. It uses a so-called projection index (PI) as a criterion to seek directions that may lead to interesting findings for data ...
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ISBN:
(纸本)0819457914
Projection pursuit (PP) is an interesting concept, which has been found in many applications. It uses a so-called projection index (PI) as a criterion to seek directions that may lead to interesting findings for data analysts. Unlike the principal components analysis (PCA), which uses variance as a measure to find directions that maximizes data variances, the PI used by the PP finds interesting directions that can be characterized by statistics higher than variance. As a result, the PCA is generally considered as a special case of PP with the PI particularly specified by the variance. Recently, a PP-based approach was developed by Ifarraguerri and Chang for multispectral/hyperspectral image analysis. This paper revisits their approach and investigates its application in endmember generation where endmembers can be extracted from a sequence of projections generated by PP.
H.264 video coding standard achieves significant improvement on coding efficiency due to its variable-block-size motion estimation (ME). However, it also leads to much higher computational complexity. This paper prese...
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ISBN:
(纸本)0780392434
H.264 video coding standard achieves significant improvement on coding efficiency due to its variable-block-size motion estimation (ME). However, it also leads to much higher computational complexity. This paper presents a novel fast predictive mode decision algorithm to accelerate the ME process for H.264 encoder. Firstly, an early-termination mechanism is introduced to determine the stationary and motion-followed macroblocks (several surrounding blocks have identical motion vectors (MVs)) with adaptive threshold. Secondly, in order to predict the M-Vs of up-layer blocks, we apply a fast predictive MV search on the 4x4 blocks in non-determined macroblocks which are not early-determined in step 1. Finally, with these predictive MVs, a bottom-up merging method is performed to finish mode decision procedure. Experimental results show that our proposed algorithm can reduce the encoding computational complexity to about 70% of JM8.5 encoder, with negligible average PSNR drop and small bitrate increase.
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