Recently, medical modalities such as low dose CT, MRI and tomosynthesis have focused on generating noise-free images by using fewer measurements. However acquiring or using less data to reconstruct an image increases ...
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ISBN:
(纸本)9781479948741
Recently, medical modalities such as low dose CT, MRI and tomosynthesis have focused on generating noise-free images by using fewer measurements. However acquiring or using less data to reconstruct an image increases the noise level in the image. Thus, image denoising has been one of the most active research areas due to the noise existence in most medical imaging modalities. Due to its virtue of edge preserving, Total Variation (TV) has been actively used in medical imaging. Non-Local Means has recently been proposed as a filtering to suppress the Gaussian noise and preserve fine details in the image. In this study, the total variation (TV) minimization, is combined with Non-Local Means (NLM) filtering to increase the noise reduction. visual and numerical results show that an important improvement in image denoising has been achieved in the sense of Structure Similarity (SSIM) and RMSE. The optimum NLM filtering parameters selection has also been studied to increase the performance the proposed method.
Content based image retrieval has gained considerable attention in nowadays as a very useful tool in a plethora of applications. Web has become the most important application, because over 70% of it is devoted to imag...
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ISBN:
(纸本)0819450235
Content based image retrieval has gained considerable attention in nowadays as a very useful tool in a plethora of applications. Web has become the most important application, because over 70% of it is devoted to images, and looking for a specific image is a really daunting task. The vast majority of these images are JPEG compressed. An extensive study of eighteen similarity measures used for image retrieval has been conducted and the corresponding results are reported in the present communication. The energy histograms of the low frequency DCT coefficients have been used as the feature space for similarity testing. Query-by-image-example was used in all tests.
This paper describes an attack on semi-fragile image authentication schemes proposed in papers In this attack, the adversary manipulates an authentic image and queries a verifier with the corrupted image. According to...
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ISBN:
(纸本)0819450235
This paper describes an attack on semi-fragile image authentication schemes proposed in papers In this attack, the adversary manipulates an authentic image and queries a verifier with the corrupted image. According to the answers from the verifier, the adversary can disclose the secret relationship graphs used to produce a signature. With the disclosed relationship graphs, the adversary can impersonate an innocent person to forge authentic images easily. A countermeasure to this attack is to change scheme parameters with the relationship edges so that the relationship graphs reconstructed by the attacker are different from the original one. Sequentially, the attacker is hard to forge an authentic image without correct relationship graphs.
In this paper, the problem of DCT information recovery in the transmission of coded visual data over packet networks is addressed. The loss of a packet conveying coded block data leads to the unsuccessful reconstructi...
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In this paper, the problem of DCT information recovery in the transmission of coded visual data over packet networks is addressed. The loss of a packet conveying coded block data leads to the unsuccessful reconstruction of the relevant area, with consequent degradation of the received image quality. The proposed method allows recovery of a subset of the missing DCT coefficients sufficient to achieve good reconstruction quality of the lost block, based on the available surrounding information. To this purpose, a neural predictor was carefully designed and suitably trained with an appropriate set of synthetic and natural patterns. An extensive testing phase, performed on a large set of images with different frequency characteristics, revealed that the method provides very good reconstruction capabilities.
In this paper a novel approach to the problem of edge preserving noise reduction in color images is proposed and evaluated. The new algorithm is based on the combined forward and backward anisotropic diffusion with in...
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ISBN:
(纸本)0819450235
In this paper a novel approach to the problem of edge preserving noise reduction in color images is proposed and evaluated. The new algorithm is based on the combined forward and backward anisotropic diffusion with incorporated time dependent cooling process. This method is able to efficiently remove image noise, while preserving and even enhancing image edges. The proposed algorithm can be used as a first step of different techniques, which are based on color. shape-and spatial location information.
Human faces are always the focus of visual attention since faces can provide plenty of information. Although some visual attention models incorporating face cues work better in scenes containing faces, no visual atten...
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ISBN:
(纸本)9781467373142
Human faces are always the focus of visual attention since faces can provide plenty of information. Although some visual attention models incorporating face cues work better in scenes containing faces, no visual attention model is particularly designed for faces. On faces, many high-level factors will influence visual attention distribution. In practice, there are many visual communication systems in which faces occupy the scenes, such as video calls. Specific visual attention model designed for face images will be of great value in these circumstances. In this paper, we conduct research on visual attention analysis and modelling on human faces. To facilitate this research, we collect 120 face images and perform eye-tracking experiments with these images. Eye-movement data shows that detailed visual attention allocation exists on faces. Using face detection and facial landmark localization, we find that some facial features are highly effective for visual attention prediction. The performance of many visual attention models can be improved by incorporating those facial features.
By dynamically distributing the channel capacity among video programs according to their respective scene complexities, joint coding has been shown to be more efficient than independent coding for compression of multi...
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ISBN:
(纸本)0819424358
By dynamically distributing the channel capacity among video programs according to their respective scene complexities, joint coding has been shown to be more efficient than independent coding for compression of multiple video programs [3]. This paper examines the bit allocation issue for joint coding of multiple video programs and provides a bit allocation strategy that results in uniform picture quality among programs as well as within a program.
With the ease of distribution of digital images, there is a growing concern for copyright control and authentication. While there are many existing watermarking and data hiding methods for natural images, almost none ...
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ISBN:
(纸本)0819437034
With the ease of distribution of digital images, there is a growing concern for copyright control and authentication. While there are many existing watermarking and data hiding methods for natural images, almost none can be applied to halftone images. In this paper, we proposed a novel data hiding method, Modified Data Hiding Ordered Dithering (MDHED) for halftone images. MDHED is an effective method to hide a relative amount of data while yielding halftone images with good visual quality Besides, the amount of hidden data is easy to control and the security depends on the key not the system itself.
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.
This paper proposes a new image steganography method of hiding multiple secret images (2 bit binary image) in a single cover image (24 bit cover image). According to the proposed method, one of the secret images is em...
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ISBN:
(纸本)9781479980819
This paper proposes a new image steganography method of hiding multiple secret images (2 bit binary image) in a single cover image (24 bit cover image). According to the proposed method, one of the secret images is embedded in a randomized nature in one of the primary color matrix of the color cover image using the least significant bit substitution technique. The other secret images are encrypted using the first secret image. From the stego-image, the first secret image embedded randomly in the cover image is extracted and then this extracted image is used to decode the remaining secret images. The focus is to secure the transmitted information even if the channel is revealed, to recognize the authenticity of the extracted images and increase the hiding capacity in a single 24-bit image maintaining the visual quality of the stego-image. Results reveal that the proposed method has low error, comparatively fast computational speed and satisfactory visual quality of the stego-image.
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