The spatial relationship of DCT coefficients between a block and its sub-blocks

Jiang, Jianmin; Feng, Guocan

doi:10.1109/78.995072

Cited by 109 publications

(7 citation statements)

References 15 publications

(28 reference statements)

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“…Then, obtain the down-sampled version of the DCT Iluminance frame via replacing each 2x2 sub-block with half of its DC coefficients [13]. The fast inter-transformation between block DCT and sub-block DCT is four times faster than the conventional method which accomplishes the same task via inverse DCT (IDCT) [14].…”

Section: A Key Frame Extraction Stagementioning

confidence: 99%

Content Based Video Retrival System for Mexican Culture Heritage Based on Object Matching and Local-Global Descriptors

Cedillo-Hernández

García-Ugalde

Cedillo-Hernandez

et al. 2014

2014 International Conference on Mechatronics, Electronics and Automotive Engineering

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Multimedia data and networking technologies have had a highly growing during the last decade; with these changes users have changed from text to contentbased video retrieval systems due to its better performance. We propose a fast content-based video retrieval system which involves the combination of a local descriptor obtained from the speededup robust feature algorithm together with an effective and fast object matching operation. To save computational time, compressed video data are partially decoded in order to get discrete cosine transform coefficients of key frames, which are used to obtain sub-block coefficients and a down-sampling version of frames. The preliminary results are ranking using an efficient color descriptor based on color correlogram and dominant color descriptors. To measure the performance of the proposed technique the precision and recall metrics are used. The experimental results show the accuracy of the proposed method applied to a database of Mexican Culture Heritage videos. Keywords-content based video retrieval; speeded up robust features;color descriptorsI.

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Section: A Key Frame Extraction Stagementioning

confidence: 99%

Content Based Video Retrival System for Mexican Culture Heritage Based on Object Matching and Local-Global Descriptors

Cedillo-Hernández

García-Ugalde

Cedillo-Hernandez

et al. 2014

2014 International Conference on Mechatronics, Electronics and Automotive Engineering

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“…These processes are highly time consuming operations. In [ 14 , 15 ], inter-transformation of DCT coefficients is proposed, in which the relationship between DCT coefficients of different block sizes is established.…”

Section: Proposed Video Processing-based Smoke Detection Schemementioning

confidence: 99%

“…According to [ 14 ], this DCT inter-transformation is four times faster than the traditional IDCT-DCT operation. In the proposed smoke detection scheme, firstly the DCT inter-transformation is applied to each frame to get S/2 × S/2 DCT blocks directly from S × S DCT blocks, where S = 8 because an IP camera is used.…”

Section: Proposed Video Processing-based Smoke Detection Schemementioning

confidence: 99%

“…The proposed algorithm detects the presence of smoke using several smoke features, such as color, motion and spreading characteristics, which are extracted directly from DCT coefficients to avoid the decoding process. To increase the resolution of video frames without significantly increasing the computational cost, fast inter-transformation of DCT coefficients proposed in [ 14 ] and [ 15 ] are used. The computer simulation results show the efficiency and high smoke detection rates of the proposed algorithm.…”

Section: Introductionmentioning

confidence: 99%

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An Early Fire Detection Algorithm Using IP Cameras

Millan-Garcia

Sánchez-Pérez

Nakano-Miyatake

et al. 2012

Sensors

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The presence of smoke is the first symptom of fire; therefore to achieve early fire detection, accurate and quick estimation of the presence of smoke is very important. In this paper we propose an algorithm to detect the presence of smoke using video sequences captured by Internet Protocol (IP) cameras, in which important features of smoke, such as color, motion and growth properties are employed. For an efficient smoke detection in the IP camera platform, a detection algorithm must operate directly in the Discrete Cosine Transform (DCT) domain to reduce computational cost, avoiding a complete decoding process required for algorithms that operate in spatial domain. In the proposed algorithm the DCT Inter-transformation technique is used to increase the detection accuracy without inverse DCT operation. In the proposed scheme, firstly the candidate smoke regions are estimated using motion and color smoke properties; next using morphological operations the noise is reduced. Finally the growth properties of the candidate smoke regions are furthermore analyzed through time using the connected component labeling technique. Evaluation results show that a feasible smoke detection method with false negative and false positive error rates approximately equal to 4% and 2%, respectively, is obtained.

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“…In this section we describe our watermarking scheme in detail, which is block-based and shares same features with the JEPG standard for still image compression. The quantized DC and the AC coefficients denote the average luminance and the different frequency band of a block which could reflect its texture respectively (Jianmin, 2002). A new approach to select the appropriate smooth blocks is given as follows:…”

Section: Proposed Watermarking Techniquementioning

confidence: 99%

Smooth Blocks-Based Blind Watermarking Algorithm in Compressed DCT Domain

Qi¹,

Zhou²,

Lü³

2006

Proceedings of the International Conference on Security and Cryptography

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A novel blind watermarking scheme based on smooth blocks in compressed DCT domain is proposed. The smooth blocks are detected by a criterion which uses a relation between the quantized DC coefficients and the variance of AC coefficients in the block and deduced from the Weber's Law. In the approach, the watermark is embedded by modifying the average value of some low-frequency DCT coefficients in selected blocks, and recovered by the sign of the mean value of corresponding coefficients in detected blocks and there is no need for original image. The experimental results demonstrate that almost no perceptible distortion is found in the watermarked images, and the watermark is robust to some image processing operations such as scaling, noise, filtering and JPEG compression.

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The spatial relationship of DCT coefficients between a block and its sub-blocks

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Cited by 109 publications

References 15 publications

Content Based Video Retrival System for Mexican Culture Heritage Based on Object Matching and Local-Global Descriptors

Content Based Video Retrival System for Mexican Culture Heritage Based on Object Matching and Local-Global Descriptors

An Early Fire Detection Algorithm Using IP Cameras

Smooth Blocks-Based Blind Watermarking Algorithm in Compressed DCT Domain

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