In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information ...In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information of the original image is a challenging problem since unknown diverse manipulations may have different characteristics and so do various formats of images.Our principle is that image processing,no matter how complex,may affect image quality,so image quality metrics can be used to distinguish tampered images.In particular,based on the alteration of image quality in modified blocks,the proposed method can locate the tampered areas.Referring to four types of effective no-reference image quality metrics,we obtain 13 features to present an image.The experimental results show that the proposed method is very promising on detecting image tampering and locating the locally tampered areas especially in realistic scenarios.展开更多
A semi-reference image quality assessment metric based on similarity measurement for synthesized virtual viewpoint image （VVI） in free-viewpoint television system （FFV） is proposed in this paper. The key point of ...A semi-reference image quality assessment metric based on similarity measurement for synthesized virtual viewpoint image （VVI） in free-viewpoint television system （FFV） is proposed in this paper. The key point of the proposed metric is taking resemblant information between VVI and its neighbor view images for quality assessment to make our metric to be extended to multi-semi-reference image quality assessment easily. The proposed metric first extracts impact factors from image features, then combines an image synthesis technique and similarity functions, in which, disparity information are taken into account for registering the resemblant regions. Experiments are divided into three phases. Phase I is to verify the validation of the proposed metric by taking impaired images and original reference into account. The experimental results show the agreement between evaluation scores and bio-characteristic of human visual system. Phase II shows the accordance with Phase I by taking neighbor view as reference. The proposed metric can be taken as a full reference one to evaluate the image quality even though the original reference is absent. Phase III is then performed to evaluate the quality of WI. Evaluation scores in the experimental results are able to evaluate the quality of VVI.展开更多
Image segmentation is an important stage in many applications such as image, video and computer processing. Generally image interpretation depends on it. The materials and methods used to demonstrate are described. Th...Image segmentation is an important stage in many applications such as image, video and computer processing. Generally image interpretation depends on it. The materials and methods used to demonstrate are described. The results are presented and analyzed. Several approaches and algorithms for image segmentation have been developed, but it is difficult to evaluate the efficiency and to make an objective comparison of different segmentation methods. This general problem has been addressed for the evaluation of a segmentation result and the results are available in the literature. In this work, we first presented some criteria of evaluation of segmentation commonly used in image processing with reviews of their models. Then multicomponent synthetic images of known composition are applied to these criteria to explore the operation and evaluate its relevance. The results show that choosing an assessment method depends on the purpose, however the criterion of Zeboudj appears powerful for the evaluation of region segmentations for properly separated classes, on the contrary the criteria of Levine-Nazif and Borsotti are adapted to the methods of classification and permit to build homogeneous regions or classes. The values of the Rosenbeger criterion are generally low and similar, so hard to make a comparison of segmentations with this criterion.展开更多
We present a method of generating high dynamic range(HDR)radiance maps from a single low dynamic range(LDR)image and its camera response function(CRF).The method first models and estimates the inverse CRF and then mul...We present a method of generating high dynamic range(HDR)radiance maps from a single low dynamic range(LDR)image and its camera response function(CRF).The method first models and estimates the inverse CRF and then multiplies the inverse CRF by a weighting function to make it smooth near the maximum and minimum pixel values,and finally conducts the smooth inverse CRF on the input LDR image to generate HDR image.In the method,the inverse CRF is estimated using one single LDR image and an empirical model of CRF,based on measured RGB distributions at color edges.Unlike most existing methods,the proposed method expands image from both high and low luminance regions.Thus,the algorithm can avoid the artifacts and detail loss in dark area which results from extending image only from bright region.Extensive experimental results show that the approach induces less contrast distortion and produces high visual quality HDR image.展开更多
Poetry is a special combination of musical and linguistic qualities—of sounds both regarded as pure sound and as mean ingful speech.Part of the pleasure of poetry lies in its relationship with music.Metrics,including...Poetry is a special combination of musical and linguistic qualities—of sounds both regarded as pure sound and as mean ingful speech.Part of the pleasure of poetry lies in its relationship with music.Metrics,including rhythm and meter,is an impor tant method for poetry to express poetic sentiment.Through the introduction of poetic language and typical examples,the writer of this paper tries to discuss the relationship between sound and meaning.展开更多
Objective image quality measure, which is a fundamental and challenging job in image processing, evaluates the image quality consistently with human perception automatically. On the assumption that any image distortio...Objective image quality measure, which is a fundamental and challenging job in image processing, evaluates the image quality consistently with human perception automatically. On the assumption that any image distortion could be modeled as the difference between the directional projection-based maps of reference and distortion images, we propose a new objective quality assessment method based on directional projection for full reference model. Experimental results show that the proposed metrics are well consistent with the subjective quality score.展开更多
Recent developments in 3D graphics technology have led to extensive processes on 3D meshes(e.g.,compression,simplification,transmission and watermarking),these processes unavoidably cause the visual perceptual degrada...Recent developments in 3D graphics technology have led to extensive processes on 3D meshes(e.g.,compression,simplification,transmission and watermarking),these processes unavoidably cause the visual perceptual degradation of the 3D objects.The existing mesh visual quality evaluation metrics either require topology constrain or fail to reflect the perceived visual quality.Meanwhile,for the 3D objects that are observed on 2D screens by the users,it is reasonable to apply image metric to assess the distortion caused by mesh simplification.We attempt to explore the efficiency of image metric for assessing the visual fidelity of the simplified 3D model in this paper.For this purpose,several latest and most effective image metrics,2D snapshots,number and pooling algorithms are involved in our study,and finally tested on the IEETA simplification database.The statistical data allow the researcher to select the optimal parameter for this image-based mesh visual quality assessment and provide a new perspective for the design and performance assessment of mesh simplification algorithms.展开更多
Constant levels of perceptual quality of streaming video is what ideall usersexpect. In most cases, however, they receive time-varying levels of quality of video. In thispaper, the author proposes a new control method...Constant levels of perceptual quality of streaming video is what ideall usersexpect. In most cases, however, they receive time-varying levels of quality of video. In thispaper, the author proposes a new control method of perceptual quality in variable bit rate videoencoding for streaming video. The image quality calculation based on the perception of human visualsystems is presented . Quantization properties of DCT coefficients are analyzed to controleffectively. Quantization scale factors are ascertained based on the visual mask effect. AProportional Integral Difference (PID) controller is used to control the image quality. Experimentalresults show that this method improves the perceptual quality uniformity of encoded video.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.60971095 and No.61172109)Artificial Intelligence Key Laboratory of Sichuan Province(Grant No.2012RZJ01)the Fundamental Research Funds for the Central Universities(Grant No.DUT13RC201)
文摘In this paper,a new approach is proposed to determine whether the content of an image is authentic or modified with a focus on detecting complex image tampering.Detecting image tampering without any prior information of the original image is a challenging problem since unknown diverse manipulations may have different characteristics and so do various formats of images.Our principle is that image processing,no matter how complex,may affect image quality,so image quality metrics can be used to distinguish tampered images.In particular,based on the alteration of image quality in modified blocks,the proposed method can locate the tampered areas.Referring to four types of effective no-reference image quality metrics,we obtain 13 features to present an image.The experimental results show that the proposed method is very promising on detecting image tampering and locating the locally tampered areas especially in realistic scenarios.
基金Supported by the National Natural Science Foundation of China (No. 60672073,60872094)the Program for New Century Excellent Talents in University (NCET-06-0537)the Natural Science Foundation of Ningbo (No. 2007A610037).
文摘A semi-reference image quality assessment metric based on similarity measurement for synthesized virtual viewpoint image （VVI） in free-viewpoint television system （FFV） is proposed in this paper. The key point of the proposed metric is taking resemblant information between VVI and its neighbor view images for quality assessment to make our metric to be extended to multi-semi-reference image quality assessment easily. The proposed metric first extracts impact factors from image features, then combines an image synthesis technique and similarity functions, in which, disparity information are taken into account for registering the resemblant regions. Experiments are divided into three phases. Phase I is to verify the validation of the proposed metric by taking impaired images and original reference into account. The experimental results show the agreement between evaluation scores and bio-characteristic of human visual system. Phase II shows the accordance with Phase I by taking neighbor view as reference. The proposed metric can be taken as a full reference one to evaluate the image quality even though the original reference is absent. Phase III is then performed to evaluate the quality of WI. Evaluation scores in the experimental results are able to evaluate the quality of VVI.
文摘Image segmentation is an important stage in many applications such as image, video and computer processing. Generally image interpretation depends on it. The materials and methods used to demonstrate are described. The results are presented and analyzed. Several approaches and algorithms for image segmentation have been developed, but it is difficult to evaluate the efficiency and to make an objective comparison of different segmentation methods. This general problem has been addressed for the evaluation of a segmentation result and the results are available in the literature. In this work, we first presented some criteria of evaluation of segmentation commonly used in image processing with reviews of their models. Then multicomponent synthetic images of known composition are applied to these criteria to explore the operation and evaluate its relevance. The results show that choosing an assessment method depends on the purpose, however the criterion of Zeboudj appears powerful for the evaluation of region segmentations for properly separated classes, on the contrary the criteria of Levine-Nazif and Borsotti are adapted to the methods of classification and permit to build homogeneous regions or classes. The values of the Rosenbeger criterion are generally low and similar, so hard to make a comparison of segmentations with this criterion.
基金supported by the National Natural Science Foundation of China (61401072)
文摘We present a method of generating high dynamic range(HDR)radiance maps from a single low dynamic range(LDR)image and its camera response function(CRF).The method first models and estimates the inverse CRF and then multiplies the inverse CRF by a weighting function to make it smooth near the maximum and minimum pixel values,and finally conducts the smooth inverse CRF on the input LDR image to generate HDR image.In the method,the inverse CRF is estimated using one single LDR image and an empirical model of CRF,based on measured RGB distributions at color edges.Unlike most existing methods,the proposed method expands image from both high and low luminance regions.Thus,the algorithm can avoid the artifacts and detail loss in dark area which results from extending image only from bright region.Extensive experimental results show that the approach induces less contrast distortion and produces high visual quality HDR image.
文摘Poetry is a special combination of musical and linguistic qualities—of sounds both regarded as pure sound and as mean ingful speech.Part of the pleasure of poetry lies in its relationship with music.Metrics,including rhythm and meter,is an impor tant method for poetry to express poetic sentiment.Through the introduction of poetic language and typical examples,the writer of this paper tries to discuss the relationship between sound and meaning.
文摘Objective image quality measure, which is a fundamental and challenging job in image processing, evaluates the image quality consistently with human perception automatically. On the assumption that any image distortion could be modeled as the difference between the directional projection-based maps of reference and distortion images, we propose a new objective quality assessment method based on directional projection for full reference model. Experimental results show that the proposed metrics are well consistent with the subjective quality score.
文摘Recent developments in 3D graphics technology have led to extensive processes on 3D meshes(e.g.,compression,simplification,transmission and watermarking),these processes unavoidably cause the visual perceptual degradation of the 3D objects.The existing mesh visual quality evaluation metrics either require topology constrain or fail to reflect the perceived visual quality.Meanwhile,for the 3D objects that are observed on 2D screens by the users,it is reasonable to apply image metric to assess the distortion caused by mesh simplification.We attempt to explore the efficiency of image metric for assessing the visual fidelity of the simplified 3D model in this paper.For this purpose,several latest and most effective image metrics,2D snapshots,number and pooling algorithms are involved in our study,and finally tested on the IEETA simplification database.The statistical data allow the researcher to select the optimal parameter for this image-based mesh visual quality assessment and provide a new perspective for the design and performance assessment of mesh simplification algorithms.
文摘Constant levels of perceptual quality of streaming video is what ideall usersexpect. In most cases, however, they receive time-varying levels of quality of video. In thispaper, the author proposes a new control method of perceptual quality in variable bit rate videoencoding for streaming video. The image quality calculation based on the perception of human visualsystems is presented . Quantization properties of DCT coefficients are analyzed to controleffectively. Quantization scale factors are ascertained based on the visual mask effect. AProportional Integral Difference (PID) controller is used to control the image quality. Experimentalresults show that this method improves the perceptual quality uniformity of encoded video.
