This paper presents a new version of the exact discrete Radon [1] transform denoted as Mojette transform. Whereas the Mojette transform backprojects a single bin into a grey value pixel at each iteration, the proposed...
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In this paper, we propose a color segmentation algorithm based on contrast information and adaptive thresholds. Given a color image, instead of the commonly used achromatic difference and chromatic difference, we use ...
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In this paper, we propose a color segmentation algorithm based on contrast information and adaptive thresholds. Given a color image, instead of the commonly used achromatic difference and chromatic difference, we use achromatic contrast and chromatic contrast to represent the significance of boundary. To fit for human's visual perception, adaptive thresholds are applied to suppress perceptually faint boundaries. A complete segmentation scheme is proposed and the simulation results demonstrate the superiority of this approach in providing reasonable and reliable color segmentation.
Wireless imaging is enabling visual communication "anytime anywhere" to become a reality. A key technical challenge is how to achieve best perceived image quality given the limited screen size and display bi...
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Wireless imaging is enabling visual communication "anytime anywhere" to become a reality. A key technical challenge is how to achieve best perceived image quality given the limited screen size and display bit depth of the mobile devices. In this paper, we give an overview of the current capabilities of various mobile devices, highlight some of the technical issues, and present potential solutions. In addition, we present a review of some of the software products on the market and look ahead to the trend towards more capable devices.
An improved Zernike moment using a region-based shape descriptor is presented. The improved Zernike moment not only has rotation invariance, but also has scale invariance that the unimproved Zernike moment does not ha...
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An autonomous segmentation process is one of the most difficult tasks of a visual system. Among the main aspects that can affect the results of this process is the presence of noise. In this paper, it is showed how a ...
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Blocking artifacts are the inherent and inevitable phenomena, at low bit rates in the current block-based video coding schemes. This paper proposes a deblocking technique to reduce blocking artifacts and improve visua...
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ISBN:
(纸本)0780374886
Blocking artifacts are the inherent and inevitable phenomena, at low bit rates in the current block-based video coding schemes. This paper proposes a deblocking technique to reduce blocking artifacts and improve visual quality. Different from the post-processing technique adopted in MPEG-4, the proposed technique is directly applied to the reference image for effective motion prediction instead of just for display purpose. In other words, the deblocking filter is introduced into the motion compensation loop in the video coding. Because of the negative effects of deblocking filter such as blurring the details of image, not every block boundary needs to be filtered. The boundaries between two blocks have to be determined whether they should be filtered or not. Therefore, we also propose a decision-making criterion based on the available motion information (vector and mode) in this paper. Experimental results show that the proposed deblocking method can improve image quality both in subjective and objective aspects. It also outperforms the post-processing technique in MPEG-4.
Due to bad storage and repeated projection. movies suffer from many degradations such as blotches, sparkle. noise or missing data in different parts. This paper examines these old movie problems and suggests the use o...
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ISBN:
(纸本)9775031729
Due to bad storage and repeated projection. movies suffer from many degradations such as blotches, sparkle. noise or missing data in different parts. This paper examines these old movie problems and suggests the use of some image restoration techniques in conjunction with the motion estimation techniques widely used in video coding to restore these pictures. The three-step method of block matching is used for motion estimation. An algorithm based on motion estimation and applying the concepts of the temporal 3D median filter is used for the restoration. The results of this method show visual improvement and high reduction of the blotches. sparkles. and missing data. Using other image enhancement techniques further improvement can be obtained.
For almost a decade, Content-Based Information Retrieval has been an active research area, yet two fundamental problems remain largely unsolved: how best to learn users' query concepts, and how to measure perceptu...
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ISBN:
(纸本)0780374029
For almost a decade, Content-Based Information Retrieval has been an active research area, yet two fundamental problems remain largely unsolved: how best to learn users' query concepts, and how to measure perceptual similarity. To learn subjective query concepts, most systems use relevance feedback techniques. However, these traditional techniques often require a large number of training instances to converge to a concept, and a typical online user may be too impatient to provide much feedback. Thus traditional relevance feedback techniques are ineffective. To measure perceptual similarity, most researchers employ the Minkowski metric or the L-norm distance function. Our extensive data-mining experiments on visual data show that, unfortunately, the Minkowski-type metric is ineffective in modeling perceptual similarity. In this paper, we report the progress we have made recently in developing more effective methods for learning and measuring perceptual similarity, and our future research plans.
In this paper, an effective content-based visualimage retrieval system is presented. This system consists of two main components: visual content extraction and indexing, and query engine. Each image in the image data...
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ISBN:
(纸本)0769517277
In this paper, an effective content-based visualimage retrieval system is presented. This system consists of two main components: visual content extraction and indexing, and query engine. Each image in the image database is represented by its visual features: color and spatial information. The system uses a color label histogram with only thirteen bins to extract the color information from an image in the image database. A unique unsupervised segmentation algorithm combined with the wavelet technique generates the spatial feature of an image automatically The resulting feature vectors are relatively low in dimensions compared to those in other systems. The query engine employs a color filter and a spatial filter to dramatically reduce the search range. As a result, queue processing is speeded tip, The experimental results demonstrate that our system is capable of retrieving images that belong to the same category.
作者：
Xing, JNASA
Ames Res Ctr Moffett Field CA 94035 USA
The perception of a visual stimulus is affected by the presence of other stimuli in its surround region. The perceived central contrast can be suppressed or enhanced by the surrounds. Our previous sychophysical result...
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ISBN:
(纸本)0819444022
The perception of a visual stimulus is affected by the presence of other stimuli in its surround region. The perceived central contrast can be suppressed or enhanced by the surrounds. Our previous sychophysical results showed that both surround suppression and enhancement existed in the foveal vision while only suppression existed in the peripheral vision. Moreover, the suppression in the periphery was much stronger than that in the fovea. In this report, we built an imageprocessing model for the vision system with lateral connections embedded. We first adjusted model parameters to make the model have the same performance as human subjects had in contrast perception experiments in fovea. and periphery respectively. With those parameters, we then analyzed the functions of lateral connections in image perception. We found that: 1) With foveal parameters, lateral interactions served the purpose of gain control and image regularization. The contrast response in the fovea was modulated by the global image through lateral connections. 2) With peripheral parameters, lateral interactions resulted in image boundary segmentation. The response to a uniform image region was suppressed while the response to the boundary regions remained. The results suggest that a visualimage be encoded differently by foveal and peripheral vision. The possible impacts of this feature on image compression were discussed.
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