• Proceedings of the Korean Information Science Society Conference
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• 2000.10b
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• pp.470-472
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• 2000

본 논문에서는 영상 정보뿐만 아니라 오디오 정보를 함께 사용한 비디오 세그멘테이션에 대해 연구하였다. 대용량의 정보를 가지고 있는 비디오에 대하여 장면 경계 검출(Scene Break Detection)을 할 경우, 카메라 팬이나 장면 내에 여려 가지 다른 샷(Shot)으로 인하여 영상 정보만으로는 효과적인 검출이 어렵다. 이러한 문제를 해결하기 위해 비디오 내의 오디오 정보도 함께 사용함으로써 문제를 개선했다. 뉴스, 광고, 스포츠 등 다양한 3개 분야의 TV 프로그램으로 구성된 약 4,000개 영상 프레임과 약 30,000개의 오디오 프레임으로 구성된 비디오 데이터베이스에 대하여 실험한 결과, 영상 정보만 사용한 경우보다 우수한 성능을 확인하였다. 영상 정보 특징값으로는 칼라 히스토그램과 DC계수를 사용했고, 오디오 특징값으로는 SR(Silence ratio), VSTD(Volume standard deviation), NPR(Non pitch ratio)을 사용했다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.947-950
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• 2014

CCTV와 차량용 블랙박스 등의 영상기반 감시장비들로 사회안전망이 구축되고 있다. 하지만 디지털 영상 획득 센서는 실세계의 다이나믹 레인지를 온전히 감지하지 못한다는 한계점을 가지고 있는데 이로 인해 역광과 같은 특정 조명 조건하에서는 발생하는 움직임들을 감지하지 못하는 문제가 있다. 이러한 문제점을 해결하기 위해 종래에는 HDR 이미지를 사용하는데, 움직임이 많은 영상에 적용하기 어렵다. 별도의 WDR 이미지 센서를 사용할 수도 있으나 가격이 비싸고 영상처리가 복잡하다는 단점이 있다. 따라서, 본 논문에서는 프레임을 목표 다이내믹 레인지별로 그룹핑하고 프레임 그룹별로 노출시간을 달리하는 다중노출 방식을 제안한다. 이 방식에 따르면 어떤 조명 조건 상황에서도 물체의 변화를 모두 검출할 수 있으며 기존 이미지 센서와 영상 감지 시스템을 그대로 사용하기에 저비용으로 구현이 가능하다는 장점이 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.381-382
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• 2007

대분분의 장면전환 검출방법은 복호화에 의한 연산량이 많고, 동영상의 매 프레임을 비교함으로 시간이 많이 소요되는 순차검색 방법이다. 이러한 문제를 해결하기 위해 압축 영역에서 시간적으로 표본화 하는 비 순차검색 방법들을 제안하였다. 비 순차검색방법은 동영상을 표본화 하는 검객간격이 중요한데 본 논문에서는 전체 동영상의 비교회수를 최소화하는 최적화된 검색간격을 구하고, 구한 검색간격을 사용하여 비 순차검색알고리즘을 제안한다. 제안한 알고리즘의 성능을 분석하기 위해 기존의 방법과 비교하여 성능의 우수성을 실험을 통해 분석하였다.

• The Journal of the Korea Contents Association
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• v.13 no.6
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• pp.20-29
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• 2013

The compression of video data is intended for real-time transmission of band-limited channels. Compressed video bit-streams are very sensitive to transmission error. If we lose packets or receive them with errors during transmission, not only the current frame will be corrupted, but also the error will propagate to succeeding frames due to the spatio-temporal predictive coding structure of sequences. Error detection and concealment is a good approach to reduce the bad influence on the reconstructed visual quality. To increase concealment efficiency, we need to get some more accurate error detection algorithm. In this paper, We hide specific data into the motion vector difference of each macro-block, which is obtained from the procedure of inter prediction mode in H.264/AVC. Then, the location of errors can be detected easily by checking transmitted specific data in decoder. We verified that the proposed algorithm generates good performances in PSNR and subjective visual quality through the computer simulation by H.324M mobile simulation tool.

• Journal of Digital Contents Society
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• v.15 no.4
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• pp.449-455
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• 2014

Detection of moving objects is a fundamental task in most of the computer vision applications, such as video surveillance, activity recognition and human motion analysis. This is a difficult task due to many challenges in realistic scenarios which include irregular motion in background, illumination changes, objects cast shadows, changes in scene geometry and noise, etc. In this paper, we propose an foreground extraction algorithm based on codebook, a database of information about background pixel obtained from input image sequence. Initially, we suppose a first frame as a background image and calculate difference between next input image and it to detect moving objects. The resulting difference image may contain noises as well as pure moving objects. Second, we investigate a codebook with color and brightness of a foreground pixel in the difference image. If it is matched, it is decided as a fault detected pixel and deleted from foreground. Finally, a background image is updated to process next input frame iteratively. Some pixels are estimated by input image if they are detected as background pixels. The others are duplicated from the previous background image. We apply out algorithm to PETS2009 data and compare the results with those of GMM and standard codebook algorithms.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7A
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• pp.733-742
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• 2008

In 3GPP LTE downlink system, initial cell search is essential for mobile station to connect to base station. In order to obtain information of the base station, the mobile station detects frame timing, frequency offset, and cell identification using primary synchronization channel(PSC) and secondary synchronization channel(SSC), which are defined in downlink OFDMA specification. In this paper, we analyze various detection algorithms in practical environment of inter-cell-interference, frequency offset, and multi-path fading channel and propose the optimal algorithm. Simulation results show that partial correlation method (for PSC acquisition) and interference cancellation method (for SSC detection) are the most superior algorithms among the applicable algorithms. Employ these two algorithms for receiver design, initial cell search is performed with 99% probability within 70ms in the channel environment considered.

• Journal of the Korea Computer Industry Society
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• v.8 no.2
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• pp.103-106
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• 2007

In order to construct a Video Database, shot change detection should be made first. But, because these processes are not automated perfectly, we need a lot of time and efforts now. And, there are many shot change detection algorithms, which can't always insure the perfect result because of the editing effects such as cut, wipe, and dissolves used in film production. Therefore, in order to receive the exact shot change, It needs the verification and correction by manual processing at any cost. Spatiotemporal slice is a simple image condensing method for the content changes of video. The editing effects are expressed on the Spatiotemporal slice in the visually noticed form of vertical line, diagonal line, curved line and gradual color changes, etc. Accordingly the parts doubted as a shot change can be easily detected by the change of the Spatiotemporal slice without replaying the video. The system proposed in this study makes it possible to delete the false detected key frames, and create the undetected key frames on the Spatiotemporal slice.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.37-42
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• 2006

This paper proposes a adaptive video watermarking algorithm according to bitrate and motion vector size in MPEG2 system. The watermark strength in the I-frames is adapted for quantization step size and the strength in the P-B-frames is adapted for quantization step size and motion vector of macroblock to make the watermark more robust against the accompanying degradation due to aggressively compression. A realtime watermark extraction is done directly in the DCT domain during MPEG decoding without full decoding of MPEG video. The experimental simulations show that the video quality results almost invisible difference between the watermarked frames and the original frames and the watermark is resistant to frame dropping, MPEG compression, GoP conversion and low pass filter attacks.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.91-97
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• 2012

This paper first proposes the speech recognition algorithm by detection of the speech and noise sections at each frame, then proposes the reduction algorithm of environmental noise by multi-band filter which removes the background noises at each frame according to detection of the speech and noise sections. The proposed algorithm reduces the background noises using filter bank sub-band domain after extracting the features from the speech data. In this experiment, experimental results of the proposed noise reduction algorithm by the multi-band filter demonstrate using the speech and noise data, at each frame. Based on measuring the spectral distortion, experiments confirm that the proposed algorithm is effective for the speech by corrupted the noise.

• Journal of the Korea Computer Industry Society
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• v.3 no.7
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• pp.901-914
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• 2002

In this paper, We propose an efficient automatic caption detection and location method, caption recognition using FE-MCBP(Feature Extraction based Multichained BackPropagation) neural network for content based retrieval of video. Frames are selected at fixed time interval from video and key frames are selected by gray scale histogram method. for each key frames, segmentation is performed and caption lines are detected using line scan method. lastly each characters are separated. This research improves speed and efficiency by color segmentation using local maximum analysis method before line scanning. Caption detection is a first stage of multimedia database organization and detected captions are used as input of text recognition system. Recognized captions can be searched by content based retrieval method.