An image sequence stabilization system that removes translational jitter while preserving intentional camera pan is presented. The video sequence is processed to acquire global camera translations from frame to frame ...
详细信息
ISBN:
(纸本)0819439886
An image sequence stabilization system that removes translational jitter while preserving intentional camera pan is presented. The video sequence is processed to acquire global camera translations from frame to frame (global interframe motion vectors) by motion estimation. The resulting motion vectors an accumulated to construct an absolute frame position vs. frame number signal. This signal is low-pass filtered to remove high frequency components caused by jitter, and retain low frequency parts representing the intentional camera pan. Correction vectors for image frames are obtained by subtracting the absolute frame position from the low-pass filtered value, and stabilization is achieved by the corresponding translation of image frames.
In this paper, a level set approach has been developed for segmentation of retinal vasculature. There have been a few studies for segmenting of blood vessels in the retinal images based on the level set method in the ...
详细信息
ISBN:
(纸本)9781467373869
In this paper, a level set approach has been developed for segmentation of retinal vasculature. There have been a few studies for segmenting of blood vessels in the retinal images based on the level set method in the literature. Because of the structure of blood vessels, it is difficult to develop such an approach. However, recently many level set methods have been developed to overcome such problems. In this study, an approach based on an augmented Lagrangian method that produces faster and more accurate results for the segmentation of blood vessels has been proposed. The accuracy of the presented method was also supported by a visual result.
In most IFS based image coding schemes, the domain blocks codebook searched is independent from the input image, identical for all range blocks of the same size, and non optimized. In order to get a good match between...
详细信息
ISBN:
(纸本)0819421030
In most IFS based image coding schemes, the domain blocks codebook searched is independent from the input image, identical for all range blocks of the same size, and non optimized. In order to get a good match between range and domain blocks, a huge codebook is used, which is both inefficient in terms of computational complexity and output bit rate. We propose to design an optimal reduced codebook for the whole image thanks to a geometrical analysis of the basic scheme. We then compare this method with a 'local' codebook method, which leads us to some conclusions about the differences between IFS and vectorial quantization (VQ) based coding schemes.
In this paper, we reveal that many conventional features used in computational image quality assessment (IQA) methods can hardly characterize perceived distortions on various image characteristics and distortion types...
详细信息
ISBN:
(纸本)9781467373142
In this paper, we reveal that many conventional features used in computational image quality assessment (IQA) methods can hardly characterize perceived distortions on various image characteristics and distortion types, thus resulting in relatively low prediction performance of visual quality scores. To solve this problem, we propose a new IQA method, called Structural Contrast-Quality Index (SC-QI) which is based on structural contrast index (SCI) as a very effective feature. SCI can adaptively quantify perceived distortions depending on various image characteristics and distortions types. In addition to SCI, some other perceptually important features that reflect effects of contrast sensitivity function and chrominance component variation are also combined into the proposed SC-QI. Our comprehensive experiments on three large IQA datasets verify that the proposed SC-QI outperforms the state-of-the-art ones while accompanying lower computational complexity.
Today's rapidly developing visual prosthesis systems can provide visual perception in the form of little light spots called as "phosphenes". Major imageprocessing studies in this area generally use only...
详细信息
A variable bit-rate HDTV coding algorithm based on motion-adaptive DCT is investigated for ATM environments in B-ISDN. Adaptive 2-layered coding, an ATM cell matrix for error correction, and a block interleave for err...
详细信息
ISBN:
(纸本)0819407429
A variable bit-rate HDTV coding algorithm based on motion-adaptive DCT is investigated for ATM environments in B-ISDN. Adaptive 2-layered coding, an ATM cell matrix for error correction, and a block interleave for error concealment are proposed to keep picture quality high by compensating for ATM cell loss. A new VLC and a congestion control scheme that restricts peak-rate and average-rate are also proposed for traffic control. The proposed algorithm is shown to reduce the coding bit-rate for HDTV conference applications in ATM environments to 10 - 30 Mb/s.
image completion has been widely used to repair damaged regions of a given digital image in a visually plausible way. However, it is difficult to infer appropriate information, meanwhile keep globally coherent just fr...
详细信息
ISBN:
(纸本)9781479961399
image completion has been widely used to repair damaged regions of a given digital image in a visually plausible way. However, it is difficult to infer appropriate information, meanwhile keep globally coherent just from the origin image when its critical parts are missing. To address this problem, we propose a novel layer-divided image completion scheme, which contains two major steps. First, we extract foregrounds of both target image and source image, and then we apply a guided Poisson surface reconstruction technique to complete the target foreground according to parameters obtained from optimal-matching calculation. Second, to fill the remaining damaged part, a related exemplar-based image completion algorithm is further devised. Several experiments and comparisons show the effectiveness and robustness of our proposed algorithm.
Secret image sharing is a popular image hiding scheme that typically uses (3, 3, n) multi-secret sharing to hide the colors of a secret image. The use of (3, 3, n) multi-secret sharing, however, can lead to informatio...
详细信息
ISBN:
(纸本)9781479961399
Secret image sharing is a popular image hiding scheme that typically uses (3, 3, n) multi-secret sharing to hide the colors of a secret image. The use of (3, 3, n) multi-secret sharing, however, can lead to information loss. In this paper, we study this loss of information from an image perspective, and show that one-third of the color values of the secret image can be leaked when the sum of any two selected share numbers is equal to the considered prime number in the secret sharing. Furthermore, we show that if the selected share numbers do not satisfy this condition (for example, when the value of each of the selected share number is less than the half of the value of the prime number), then the colors of the secret image are not leaked. In this case, a noise-like image is reconstructed from the knowledge of less than three shares.
image retrieval is a two steps process: 1) indexing, in which a set or a vector of features summarizing the properties of each image in the database, is computed and stored;and 2) retrieval, in which the features of t...
详细信息
ISBN:
(纸本)0819450235
image retrieval is a two steps process: 1) indexing, in which a set or a vector of features summarizing the properties of each image in the database, is computed and stored;and 2) retrieval, in which the features of the query image are extracted and compared with the others in the database. The database images are then ranked in order of their similarity. We introduce an innovative image retrieval strategy, the Dynamic Spatial Chromatic Histogram, which makes it possible to take into account spatial information in a flexible way without greatly adding to computation costs. Our preliminary results on a database of about 3000 images show that the proposed indexing and retrieval strategy is a powerful approach.
In this paper, we introduce an unequal error protection technique for foveation-based error resilience over highly error-prone mobile networks. For point-to-point visualcommunications, visual quality can be significa...
详细信息
ISBN:
(纸本)0780362985
In this paper, we introduce an unequal error protection technique for foveation-based error resilience over highly error-prone mobile networks. For point-to-point visualcommunications, visual quality can be significantly increased by using foveation-based error resilience where each frame is divided into foveated and background layers according to the gaze direction of the human eye, and two bitstreams are generated. In an effort to increase the source throughput of foveated layer, we employ unequal delay-constrained ARQ and RCPC (rate compatible punctured convolutional) codes in H.223 Annex C. In the simulation, the visual quality is increased in the range of 0.3 dB to 1 dB over channel SNR 5 dB to 15 dB.
暂无评论