Facial expression recognition is increasingly gaining importance in emerging affective computing applications. In practice, achieving accurate facial expression recognition is still challenging due to environmental va...
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ISBN:
(纸本)9781509041176
Facial expression recognition is increasingly gaining importance in emerging affective computing applications. In practice, achieving accurate facial expression recognition is still challenging due to environmental variations. In this paper, we propose a color channel-wise recurrent facial feature learning. The proposed method adopts recurrent neural network to learn expression features sequentially along color channels. The proposed network preserves discriminative expression feature through a long short-term memory for the sequence of color spatial features. Comprehensive experiments have been conducted on the publically available CMU Multi-PIE dataset under illumination variations. Experimental results showed that the proposed method achieved higher recognition rates compared to the state-of-the-art methods.
The lack of a natural ordering on the sphere presents an inherent problem when defining morphological operators extended to unit sphere. We analyze here the notion of averaging over the unit sphere to obtain a local o...
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ISBN:
(纸本)9781467325332;9781467325349
The lack of a natural ordering on the sphere presents an inherent problem when defining morphological operators extended to unit sphere. We analyze here the notion of averaging over the unit sphere to obtain a local origin which can used to formulate ordering based operators. The notion of local supremum and infimum is introduced, which allows to define the dilation and erosion for images valued on the sphere. The algorithms are illustrated using polarimetric images.
We propose a low complexity method for segmentation of text regions in natural images. This algorithm is designed for mobile applications (e. g. unmanned or hand-held devices) in which computational and energy resourc...
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ISBN:
(纸本)9781424442966
We propose a low complexity method for segmentation of text regions in natural images. This algorithm is designed for mobile applications (e. g. unmanned or hand-held devices) in which computational and energy resources are limited. No prior assumption is made regarding the text size, font, language, character set or the camera angle. However, the text is assumed to be located on a piecewise homogeneous background with a contrasting color. We have deployed our method on a Nokia N800 Internet tablet as part of a system for automatic detection and translation of outdoor signs. Our experiments show that the 0.3 megapixel images taken by the phone camera can be accurately segmented within the device in a fraction of a second.
This paper presents a method of stereoscopic panoramic video generation including techniques for panorama projection, stitching and calibration for various depth planes. The methods described can be used on video sequ...
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ISBN:
(纸本)0780376633
This paper presents a method of stereoscopic panoramic video generation including techniques for panorama projection, stitching and calibration for various depth planes. The methods described can be used on video sequences captured by an arrangement of multiple pairs of cameras or multiple stereoscopic cameras mounted on a regular polygonal shaped camera rig. Algorithms can also be used in combination or separately, for generating both stereoscopic and monoscopic video and still panoramas.
A JPEG-based perceptual image coder is proposed in this work, where a block-based image quality metric is used to optimize the rate-quality (RQ) performance. Under this framework, the quality of each image block is me...
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ISBN:
(纸本)9781467325332;9781467325349
A JPEG-based perceptual image coder is proposed in this work, where a block-based image quality metric is used to optimize the rate-quality (RQ) performance. Under this framework, the quality of each image block is measured using a local quality metric while the overall image quality is evaluated by summing up all local quality metrics. A rate-quality optimization (RQO) problem is formulated in each macroblock of size 16x16 based on its associated empirical RQ curve. Then, to achieve the best perceptual image quality under a given bit budget constraint, the set of optimal quantization parameters (QPs) for image blocks is solved using the Lagrangian approach. It is demonstrated that the proposed perceptual image codec offers a significant improvement over the JPEG baseline in both subjective and objective evaluations.
The application of compressed sensing (CS) to MRI has the potential to significantly reduce scan time. However, the quality of reconstructed images will be degraded when the MR images have strong phase variations. In ...
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ISBN:
(纸本)9781479928934
The application of compressed sensing (CS) to MRI has the potential to significantly reduce scan time. However, the quality of reconstructed images will be degraded when the MR images have strong phase variations. In the present paper, we propose a new CS method that is easy to implement and robust to phase variations on MR images. When the signal trajectory in k-space is symmetrical with respect to its origin, the k-space signal corresponding to the real and imaginary parts of the complex image can be synthesized independently by restricting the k-space signal to an even function or an odd function. The proposed method involves random but symmetrical k-space acquisition and independent reconstruction of the real and imaginary parts of images using the real-valued constraint. Several numerical experiments demonstrate that the proposed CS method provides a better quality of images compared to the other methods.
Conventional 2-D discrete cosine transform (DCT) and 2-D discrete wavelet transform (DWT) have not been taken image orientation information into account. At the same time, to remove the speckle noise in ultrasound ima...
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ISBN:
(纸本)9781424421787
Conventional 2-D discrete cosine transform (DCT) and 2-D discrete wavelet transform (DWT) have not been taken image orientation information into account. At the same time, to remove the speckle noise in ultrasound image is also a hard nut to crack. Based on above two issues, aiming at the sectorial ultrasound image, the paper proposes directional DCT-DWT hybrid transform. The proposed rays' or arts' DCT and DWT can be adopted for an image after the coordinate transform for the pixels of the image. Since the radiate wave directions are considered, the algorithm based proposed 2-D hybrid transform can inhibit the speckle noise of the ultrasound images. The experiment result verifies the proposed algorithm to be valid.
We consider the problem of sampling signals which are not bandlimited, but still have a finite number of degrees of freedom per unit of time, such as, for example, piecewise polynomials. We demonstrate that by using a...
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ISBN:
(纸本)0780370414
We consider the problem of sampling signals which are not bandlimited, but still have a finite number of degrees of freedom per unit of time, such as, for example, piecewise polynomials. We demonstrate that by using an adequate sampling kernel and a sampling rate greater or equal to the number of degrees of freedom per unit of time, one can uniquely reconstruct such signals. This proves a sampling theorem for a wide class of signals beyond bandlimited signals. applications of this sampling theorem can be found in signalprocessing, communication systems and biological systems.
In multi-channel images (e.g. color images with R, G, B channel, and multi-spectral images), there exist higher-order correlations among the channels. We develop a new MRF-MAP (Markov random field - maximum a posterio...
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ISBN:
(纸本)9781424407286
In multi-channel images (e.g. color images with R, G, B channel, and multi-spectral images), there exist higher-order correlations among the channels. We develop a new MRF-MAP (Markov random field - maximum a posteriori) framework that can be used for various multi-channel imageprocessing. Main features of the proposed framework is that the higher-order correlation between the channels is considered, whereas it is not well addressed in the conventional works[4, 8]. Given a channel image, the prior probability of another channel is computed based on the MRF modeling that the channel correlation is described as piecewise linear relationship. An optimization algorithm for the MAP estimation is also developed. The effectiveness of the proposed priors is demonstrated with a simple application, i.e., image denoising.
With advances in image display technology, recapturing good-quality images from the high-fidelity artificial scenery on a LCD screen becomes possible. Such image recapturing posts a security threat, which allows the f...
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ISBN:
(纸本)9781424442966
With advances in image display technology, recapturing good-quality images from the high-fidelity artificial scenery on a LCD screen becomes possible. Such image recapturing posts a security threat, which allows the forgery images to bypass the current forensic systems. In this paper, we first recapture some good-quality photos on different LCD screens by properly setting up the recapturing environment and tuning the controllable settings. In a perceptional study, we find that such finely recaptured images can hardly be identified by human eyes. To prevent the image recapturing attack, we propose a set of statistical features, which capture the common anomalies introduced in the camera recapturing process on LCD screens. With a probabilistic support vector machine classifier, comparison results show that our proposed features work very well, which outperform the conventional image forensic features in identification of the finely recaptured images.
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