We introduce in the present paper a fast 3D fractal encoding method based on tree compression and achieving good compression ratio at very low bit rate. The algorithm is also open to transposition on the space of wave...
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ISBN:
(纸本)0819421030
We introduce in the present paper a fast 3D fractal encoding method based on tree compression and achieving good compression ratio at very low bit rate. The algorithm is also open to transposition on the space of wavelet coefficients.
In this paper we describe some of the research issues and challenges in image-based location awareness and navigation. We will describe two systems being developed at Purdue University as test beds for our ideas. The ...
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ISBN:
(纸本)0819452114
In this paper we describe some of the research issues and challenges in image-based location awareness and navigation. We will describe two systems being developed at Purdue University as test beds for our ideas. The main system architecture combines imageprocessing, mobility, wireless communication, and location awareness. We will describe two fundamental scenarios for using images to aid in mobile navigation problems. The first provides the ability to use a locally acquired image to determine the identity of an object, for example a building, as one roams in an area. The second problem is the use of images in a database to aid in vehicle navigation. The solution to these problems use location information, such as GPS signals, to compare and search location-annotated images in a database. We believe location information can improve the accuracy in image database search.
We describe ongoing work at JPL in two fields: autonomous navigation for terrestrial vehicles, and prioritized progressive transmission for deep space communications. While such applications may seem rather disparate,...
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ISBN:
(纸本)076951183X;0769511848
We describe ongoing work at JPL in two fields: autonomous navigation for terrestrial vehicles, and prioritized progressive transmission for deep space communications. While such applications may seem rather disparate, the), have in common the need for autonomous reasoning about visual information. We first review a number of techniques currently, under development that make use of data from color and infrared cameras, multispectral sensors, and laser rangefinder for estimating properties of the terrain cover in outdoor vegetated terrain. We then discuss how onboard visual analysis mechanisms for Mars rovers can be used for prioritizing the data to be transmitted to Earth, in order to maximize the science return of a mission.
With desktop imaging devices becoming ubiquitous, effectively managing the images in large collections has become a challenge. The requirements for a modem imaging system now demand not only efficient storage (low bit...
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ISBN:
(纸本)0819439886
With desktop imaging devices becoming ubiquitous, effectively managing the images in large collections has become a challenge. The requirements for a modem imaging system now demand not only efficient storage (low bit rate coding), but also easy manipulation, indexing and retrieval of images. In this paper, we introduce a new method for colour image coding based on a visual appearance model of local colour image patterns. The visual appearance of small image patterns is characterised by their spatial pattern, colour direction and local energy strength. To encode the local visual appearance, an approach based on vector quantisation (VQ) is introduced. A separate VQ is designed for the spatial pattern and colour direction respectively. It is shown that the method not only achieves good image coding results in terms of rate distortion criterion, it also enables content-based retrieval to be performed in the compressed domain easily and conveniently.
In this paper we assess the independence of the optimization of source and channel coding parameters. We propose a method to separate the source and channel coding optimization as much as possible while maintaining th...
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ISBN:
(纸本)0819437034
In this paper we assess the independence of the optimization of source and channel coding parameters. We propose a method to separate the source and channel coding optimization as much as possible while maintaining the possibility of joint optimization. We theoretically derive key parameters that must be passed through an interface between source and channel coding. This separation greatly reduces the complexity of the optimization problem and enhances the flexibility.
The anisotropic wavelet packet transform is an extension of the conventional wavelet (packet) transform where the basis can have different scales in different dimensions. As there are certain kinds of images with diff...
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ISBN:
(纸本)0819450235
The anisotropic wavelet packet transform is an extension of the conventional wavelet (packet) transform where the basis can have different scales in different dimensions. As there are certain kinds of images with different behaviour in horizontal and vertical direction, anisotropic wavelet packet bases can be adapted more precisely to these images. Zero-tree image compression has already proved its efficiency on conventional wavelet transformed data as well as for wavelet packets. In this work, zero-tree methods are extended to work with anisotropic wavelet packets and coding results are shown for several types of images.
In this paper, we present a novel local-based algorithm for stereo matching using Gabor-Feature-image and Confidence-Mask. Various local-based schemes have been proposed in recent years, most of them mainly use color ...
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ISBN:
(纸本)9781479902880
In this paper, we present a novel local-based algorithm for stereo matching using Gabor-Feature-image and Confidence-Mask. Various local-based schemes have been proposed in recent years, most of them mainly use color difference as evaluation criterion when constructing the initial cost volume, however, color channel is highly sensitive to noise, illumination changes, etc. Therefore, we develop a new cost function based on Gabor-Feature-image for obtaining a more accurate matching cost volume. Furthermore, in order to eliminate the matching ambiguities brought by the winner-takes-all method, an effective disparity refinement strategy using Confidence-Mask is implemented to select and refine the less reliable pixels. The proposed algorithm ranks 23th out of over 150 (global-based and local-based) methods on Middlebury data sets, both quantitative and qualitative evaluation show that it is comparable to state-of-the-art local-based stereo matching algorithms.
Low bit rate image coding is essential for many visual communication applications. However, it yields visually annoying artifacts that highly degrade the perceptual quality of image data. In this paper we propose a no...
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ISBN:
(纸本)0819437034
Low bit rate image coding is essential for many visual communication applications. However, it yields visually annoying artifacts that highly degrade the perceptual quality of image data. In this paper we propose a novel method for reducing the blocking artifact that occurs when using DCT image coding at low bit rates. The blocking artifact has varied visibility in different region, that is, it is more visible in a smooth region than detailed region such as textures and edges. Hence, the proposed method is based on image segmentation and then thresholding the coefficients of different regions with adaptive thresholds. The proposed method gives consistent improvement over the previous methods for deblocking in term of peak signal-to-noise ratio (PSNR), edge variance (EV), and visual quality.
Pre-processing algorithms improve on the performance of a video compression system by removing spurious noise and insignificant features from the original images. This increases compression efficiency and attenuates c...
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ISBN:
(纸本)0819439886
Pre-processing algorithms improve on the performance of a video compression system by removing spurious noise and insignificant features from the original images. This increases compression efficiency and attenuates coding artifacts. Unfortunately, determining the appropriate amount of pre-filtering is a difficult problem, as it depends on both the content of an image as well as the target bit-rate of compression algorithm. In this paper, we explore a pre-processing technique that is loosely coupled to the quantization decisions of a rate control mechanism. This technique results in a pre-processing system that operates directly on the Displaced Frame Difference (DFD) and is applicable to any standard-compatible compression system. Results explore the effect of several standard filters on the DFD. An adaptive technique is then considered.
We introduce techniques that improve the error resilience of JPEG2000 against packet losses. The presented methods operate on JPEG2000 codestreams and consider the properties of different codestream segments. Experime...
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ISBN:
(纸本)0819444111
We introduce techniques that improve the error resilience of JPEG2000 against packet losses. The presented methods operate on JPEG2000 codestreams and consider the properties of different codestream segments. Experiments indicate that error resilience of JPEG2000 codestreams against packet losses can be improved significantly using these techniques. The performance of the proposed methods compares favorably with existing algorithms.
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