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Quantization (image processing)

About: Quantization (image processing) is a research topic. Over the lifetime, 7977 publications have been published within this topic receiving 126632 citations.


Papers
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Journal ArticleDOI
01 Nov 2006
TL;DR: The method for suppressing noise caused by memory reduction such as quantization when a specific pattern is applied such as a dithering image is discussed.
Abstract: The authors have developed a feedforward driving technique with frame memory reduction as a LCD overdrive. Adapting an image compression technique for reduction of stored a frame image data, has resulted in the construction a frame memory with fewer DRAM. In this report we discuss the method for suppressing noise caused by memory reduction such as quantization when a specific pattern is applied such as a dithering image.

32 citations

Patent
Kimoto Takahiro1
17 Jan 2002
TL;DR: In this paper, a code volume control section refers to an input image and a reference image stored in a frame memory and thereby sets a quantization step for each block so that the volume of coded data generated for a frame will be a preset volume.
Abstract: A code volume control section refers to an input image and a reference image stored in a frame memory and thereby sets a quantization step for each block so that the volume of coded data generated for a frame will be a preset volume. A data loss probability estimation section estimates a data loss probability (the probability that data loss will occur to a target block due to transmission error) based on a code volume predicted value of the target block obtained by the code volume control section and the code volume from the latest synchronization code pattern to a block just before the target block. A degradation estimation calculation section calculates an estimate of degradation of the target block caused by errors based on image degradation power and the data loss probability. A mode selection section selects an optimum encoding mode for the target block based on the degradation estimate of the target block and an estimate of frame coding distortion. Forced refresh (intra-frame encoding of a block) is carried out properly and effectively, thereby image degradation is reduced without deteriorating coding efficiency.

31 citations

Proceedings ArticleDOI
29 Nov 2011
TL;DR: A forensic algorithm to discriminate between original and forged regions in JPEG images, under the hypothesis that the tampered image presents a non-aligned double JPEG compression (NA-JPEG).
Abstract: In this paper, we present a forensic algorithm to discriminate between original and forged regions in JPEG images, under the hypothesis that the tampered image presents a non-aligned double JPEG compression (NA-JPEG). Unlike previous approaches, the proposed algorithm does not need to manually select a suspect region to test the presence or the absence of NA-JPEG artifacts. Based on a new statistical model, the probability for each 8 × 8 DCT block to be forged is automatically derived. Experimental results, considering different forensic scenarios, demonstrate the validity of the proposed approach.

31 citations

Journal ArticleDOI
TL;DR: The generalized Gaussian distribution is employed first to model the DCT coefficients of image data from MPEG-4 fine-granularity scalability (FGS) frame and a rate-distortion (R-D) model is proposed to approximate the actual distortion-rate function.
Abstract: In this paper, the generalized Gaussian distribution is employed first to model the DCT coefficients of image data from MPEG-4 fine-granularity scalability (FGS) frame. Then, according to the quantization theory, the distortion-rate function of the generalized Gaussian model is analyzed and it is concluded that the derivative of the distortion-rate function first decreases, and then increases up to the boundary of 6.02 as the bit rate increases. For actual FGS coding, the derivative of actual distortion-rate function usually decreases as the rate increases, and then begins to increase slowly at a comparatively high bit rate. Finally, based on above observations, a rate-distortion (R-D) model is proposed to approximate the actual distortion-rate function. Experiments show that the proposed R-D model is accurate and flexible.

31 citations

Book ChapterDOI
28 Aug 2012
TL;DR: A method that automatically and efficiently discriminates single- and double-compressed regions based on the JPEG ghost principle is proposed and experiments show that the detection results are highly competitive with state-of-the-art methods.
Abstract: We present a method for automating the detection of the so-called JPEG ghost s. JPEG ghost s can be used for discriminating single- and double JPEG compression, which is a common cue for image manipulation detection. The JPEG ghost scheme is particularly well-suited for non-technical experts, but the manual search for such ghost s can be both tedious and error-prone. In this paper, we propose a method that automatically and efficiently discriminates single- and double-compressed regions based on the JPEG ghost principle. Experiments show that the detection results are highly competitive with state-of-the-art methods, for both, aligned and shifted JPEG grids in double-JPEG compression.

31 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20228
2021354
2020283
2019294
2018259
2017295