Reduction of blocking effect in DCT-coded images based on a visual perception criterion

Coudoux, François-Xavier; Gazalet, M.; Corlay, Patrick

doi:10.1016/s0923-5965(96)00045-8

Cited by 28 publications

(18 citation statements)

References 8 publications

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“…2͒. The choice of the gradient operator is based on the following hypothesis by considering the human visual response to the blocking effect: 19 blockiness occurs at block boundaries, owing to the coarse quantization of the low detail uniform regions. When an observer looks through a uniform area in an image, the human eye expects to perceive a continuous gradual luminous variation.…”

Section: Block Edge Detectionmentioning

confidence: 99%

Picture quality measurement based on block visibility in discrete cosine transform coded video sequences

Coudoux

Gazalet

Derviaux

et al. 2001

J. Electron. Imaging

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In this paper, we present a perceptual measure that predicts the visibility of the well-known blocking effect in discrete cosine transform (DCT) coded image sequences. The main objective of this work is to use the results of the measure derived for adaptive video postprocessing, in order to significantly improve the visual quality of the video decoded sequences at the receiver. The proposed measure is based on a visual model accounting for both the spatial and temporal properties of the human visual system. The input of the visual model is the distorted sequence only. Psycho-visual experiments have been carried out to determine the eye sensitivity to blocking artifacts, by varying a number of visually significant parameters: background level, spatial, and temporal activities in the surrounding image. Results obtained for the measurement of the visibility thresholds enable us to estimate the model parameters. The visual model is finally applied to real coded video sequences. The comparison of measurement results with subjective tests shows that the proposed perceptual measure has a good correlation with subjective evaluation.

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Section: Block Edge Detectionmentioning

confidence: 99%

Picture quality measurement based on block visibility in discrete cosine transform coded video sequences

Coudoux

Gazalet

Derviaux

et al. 2001

J. Electron. Imaging

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“…A minimum mean square error filter in [3] and a perceptual filter in [8] is used to iteratively reduce the blocking effect. In [4] the blocking artifacts are modeled as 2D signals in the DCT domain and visual parameter based on HVS properties is used to reduce them. In [6] a method is proposed where the processed image is obtained by averaging the shifted and JPEG recompressed versions of the original compressed image.…”

Section: Introductionmentioning

confidence: 99%

“…The map is then used to control the blocking effect by adapting (for each pixel) the filtering strength according to the associated map. Deblocking algorithms in the transform domain and visibility map based methods proposed in [4,7,8] involve extensive computation. The proposed method is implemented in the spatial domain and yields better results than some of the deblocking methods considered state of the art, at much lower computational complexity.…”

Section: Introductionmentioning

confidence: 99%

Iterative blocking artefact reduction based on local contrast information

Saleem

Beghdadi

Chetouani

et al. 2011

2011 IEEE International Symposium on Signal Processing and Information Technology (ISSPIT)

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Block based transform coding is the most popular technique for image and video compression. However, images compressed using block based algorithms exhibit highly visible blocking artifacts. We propose an iterative algorithm to reduce these artifacts using a map computed by summation of the horizontal and vertical profiles of the gradient vector magnitude. This map is then used as an input to a recursive filter to reduce the blocking effect. The results of the proposed method have been compared to some recent and efficient deblocking algorithms. Experimental results show that the proposed method is simple and yields a subjective quality that is nearly free of blocking artifacts.

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“…In [5], the blocking artefacts are modelled as 2D signals in the DCT-coded images. By taking into account some HVS properties, a visual parameter in the vicinity of the inter-block boundary is used to remove the blocking effect.…”

Section: Introductionmentioning

confidence: 99%