This paper summaries the state-of-the-art of image quality assessment (IQA) and human visual system (HVS). IQA provides an objective index or real value to measure the quality of the specified image. Since human being...
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ISBN:
(纸本)9780819482341
This paper summaries the state-of-the-art of image quality assessment (IQA) and human visual system (HVS). IQA provides an objective index or real value to measure the quality of the specified image. Since human beings are the ultimate receivers of visual information in practical applications, the most reliable IQA is to build a computational model to mimic the HVS. According to the properties and cognitive mechanism of the HVS, the available HVS-based IQA methods can be divided into two categories, i.e., bionics methods and engineering methods. This paper briefly introduces the basic theories and development histories of the above two kinds of HVS-based IQA methods. Finally, some promising research issues are pointed out in the end of the paper.
Subjectively-rated image databases have become increasingly popular in the evaluation of image quality measurement algorithms. Several groups recently have improved their metrics' performance in matching these dat...
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ISBN:
(纸本)9780819482341
Subjectively-rated image databases have become increasingly popular in the evaluation of image quality measurement algorithms. Several groups recently have improved their metrics' performance in matching these databases, using particular HVS (human visual system) properties or image statistical models. However, it is difficult to know whether these improvements are due to progress towards mimicking the perceptual properties, or are due to matching some characteristics of the databases. This paper demonstrates an inherent limitation in using such databases, showing that our very simple metric, built on the contrast masking effect, is able to perform as good as many state-of-the-art metrics. It is also argued that existent databases neither contain enough images with particularly biased distortions to test the significance of single HVS property, nor cover diverse distortion types to reflect the requirement of emerging applications.
images encoded at low bit rate may suffer from blocking artifacts, which dramatically degrade the visual quality. In this paper, we propose a postprocessingimage restoration scheme for JPEG compressed images based on...
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ISBN:
(纸本)9780819482341
images encoded at low bit rate may suffer from blocking artifacts, which dramatically degrade the visual quality. In this paper, we propose a postprocessingimage restoration scheme for JPEG compressed images based on the maximum a posteriori criterion. A degradation model, represent by additive Gaussian noise model, is proposed to simulate JPEG compression process, while the original image is modeled as a high order Markov random field (MRF) based on the fields of experts framework. Meanwhile, an enhancement algorithm is proposed to restore the high frequency (HF) components. Experiment results have demonstrated that the proposed scheme can reproduce higher-quality images in terms of both objective and subjective quality.
As the performance-indicator of the imageprocessing algorithms or systems, image quality assessment (IQA) has attracted the attention of many researchers. Aiming to the widely used compression standards, JPEG and JPE...
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ISBN:
(纸本)9780819482341
As the performance-indicator of the imageprocessing algorithms or systems, image quality assessment (IQA) has attracted the attention of many researchers. Aiming to the widely used compression standards, JPEG and JPEG2000, we propose a new no reference (NR) metric for compressed images to do IQA. This metric exploits the causes of distortion by JPEG and JPEG2000, employs the directional discrete cosine transform (DDCT) to obtain the detail and direction information of the images and incorporates with the visual perception to obtain the image quality index. Experimental results show that the proposed metric not only has outstanding performance on JPEG and JPEG2000 images, but also applicable to other types of artifacts.
New 3D video representations enable new modalities of interaction, such as haptic interaction, with 2D and 3D video for truly immersive media applications. Haptic interaction with video includes haptic structure and h...
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ISBN:
(纸本)9780819482341
New 3D video representations enable new modalities of interaction, such as haptic interaction, with 2D and 3D video for truly immersive media applications. Haptic interaction with video includes haptic structure and haptic motion for new immersive experiences. It is possible to compute haptic structure signals from 3D scene geometry or depth information. This paper introduces the concept of haptic motion, as well as new methods to compute haptic structure and motion signals for 2D video-plus-depth representation. The resulting haptic signals can be rendered using a haptic cursor attached to a 2D or 3D video display.
In this paper, we present a new no-reference quality assessment metric for color images by using biologically inspired features (BIFs) and machine learning. In this metric, we first adopt a biologically inspired model...
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ISBN:
(纸本)9780819482341
In this paper, we present a new no-reference quality assessment metric for color images by using biologically inspired features (BIFs) and machine learning. In this metric, we first adopt a biologically inspired model to mimic the visual cortex and represent a color image based on BIFs which unifies color units, intensity units and C1 units. Then, in order to reduce the complexity and benefit the classification, the high dimensional features are projected to a low dimensional representation with manifold learning. Finally, a multiclass classification process is performed on this new low dimensional representation of the image and the quality assessment is based on the learned classification result in order to respect the one of the human observers. Instead of computing a final note, our method classifies the quality according to the quality scale recommended by the ITU. The preliminary results show that the developed metric can achieve good quality evaluation performance.
This paper presents an edge-preserving fourth order partial differential equation (PDE) for image restoration derived from a new surface-based energy functional. The corresponding fourth order PDE can preserve edges a...
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ISBN:
(纸本)9780819482341
This paper presents an edge-preserving fourth order partial differential equation (PDE) for image restoration derived from a new surface-based energy functional. The corresponding fourth order PDE can preserve edges and avoid the staircase effect. The proposed model contains a function of gradient norm as an edge detector, which controls the diffusion speed according to the local structure of the image and preserves more details. Denoising results are given and we have also compared our method with some related PDE models.
It is known that the 2-D DCT basis is complete and orthogonal in a rectangular region. In this paper, we introduce the way to generate the complete and orthogonal 2-D DCT basis in a trapezoid region or a triangular re...
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ISBN:
(纸本)9780819482341
It is known that the 2-D DCT basis is complete and orthogonal in a rectangular region. In this paper, we introduce the way to generate the complete and orthogonal 2-D DCT basis in a trapezoid region or a triangular region without using the complicated Gram-Schmidt method. Moreover, since a polygon can be decomposed several triangular regions, the proposed method is also suitable for the polygonal region. Our algorithm can much generalize the JPEG algorithm. Instead of dividing an image into 8 by 8 blocks, we can divide an image into trapezoid or triangular regions and then transform and code each of them. In addition to the DCT basis, our method can also be used for generating the 2-D complete and orthogonal DFT basis, KLT basis, Legendre basis, Hadamard (Walsh) basis, and polynomial basis in the trapezoid and triangular regions.
In this paper we present a complete framework for scene categorization that builds upon and extends several recent ideas including spatial pyramid representation and a variety of base local descriptors which have diff...
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ISBN:
(纸本)9780819482341
In this paper we present a complete framework for scene categorization that builds upon and extends several recent ideas including spatial pyramid representation and a variety of base local descriptors which have different discriminative power and invariance from task to task. Furthermore, we propose two strategies: sum-max and max-max, used to effectively combine diverse source of data in a unified setting way. Our approach shows significantly improved performance on a large, challenging data set of fifteen natural scene categories. Owing to combination of complementary information cues, our approach is expected to equally applicable to a range of tasks.
Current image representation schemes have limited capability of representing 2D singularities (e. g., edges in an image). Wavelet transform has better performance in representing 1D singularities than Fourier transfor...
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ISBN:
(纸本)9780819482341
Current image representation schemes have limited capability of representing 2D singularities (e. g., edges in an image). Wavelet transform has better performance in representing 1D singularities than Fourier transform. Recently invented ridgelet and curvelet transform achieve better performance in resolving 2D singularities than wavelet transform. To further improve the capability of representing 2D singularities, this paper proposes a new transform called ripplet transform Type II (ripplet-II). The new transform is able to capture 2D singularities along a family of curves in images. In fact, ridgelet transform is a special case of ripplet-II transform with degree 1. Ripplet-II transform can be used for feature extraction due to its efficiency in representing edges and textures. Experiments in texture classification and image retrieval demonstrate that the ripplet-II transform based scheme outperforms wavelet and ridgelet transform based approaches.
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