• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.9
• /
• pp.111-118
• /
• 2014

This paper presents an efficient Markov feature extraction method for detecting splicing forged images. The Markov states used in our method are composed of the difference between DCT coefficients in the adjacent blocks. Various first-order Markov state transition probabilities are extracted as features for splicing detection. In addition, we propose a feature reduction algorithm by analysing the distribution of the Markov probability. After training the extracted feature vectors using the SVM classifier, we determine whether the presence of the image splicing forgery. Experimental results verify that the proposed method shows good detection performance with a smaller number of features compared to existing methods.

• Journal of IKEEE
• /
• v.22 no.2
• /
• pp.227-232
• /
• 2018

Nowadays, image manipulation is enormously popular and easier than ever with tons of convenient images editing tools. After several simple operations, users can get visually attractive images which easily trick viewers. In this paper, we propose a fast algorithm which can detect the image splicing using the Markov features. The proposed algorithm reduces the computational complexity by removing unnecessary Markov features which are not used in the image splicing detection process. The performance of the proposed algorithm is evaluated using a famous image splicing dataset which is publicly available. The experimental results show that the proposed technique outperforms the state-of-the-art splicing detection methods.

• The Journal of the Acoustical Society of Korea
• /
• v.21 no.7
• /
• pp.641-647
• /
• 2002

In this paper, we propose the reduction method of the number of parameters in the segmental-feature HMM using trend quantization method. The proposed method shares the trend information of the polynomial trajectories by quantization. The trajectory is obtained by the sequence of feature vectors of speech signals and can be divided by trend and location information. The trend indicates the variation of consequent frame features, while the location points to the positional difference of the trajectories. Since the trend occupies the large portion of SFHMM, if the trend is shared, the number of parameters maybe decreases. To exploit the proposed system the experiments are performed on TIMIT corpus. The experimental results show that the performance of the proposed system is roughly similar to that of previous system. Therefore, the proposed system can be considered one of parameter reduction method.

• Proceedings of the Korea Society for Simulation Conference
• /
• 2005.11a
• /
• pp.33-38
• /
• 2005

지문분류는 대규모 인증시스템에 사용되는 지문 데이터 베이스를 종류별로 인덱싱 하거나 인식 시스템에 다양하게 쓰이는 매우 중요한 방법이다. 지문은 일반적으로 융선의 전체모양 등 전역적인 특징을 기반으로 분류하며, 분류방법에는 규칙기반 접근, 구문론적 접근, 구조적 접근, 통계적 접근, 신경망 기반 접근 등이 있다. 본 논문에서는 지문의 구조적인 특징을 바탕으로 관찰되는 특징의 상태가 매순간 변화하는 확률론적 정보추출 방식인 마코프 모델을 적용한 지문분류 방법을 제안한다. 지문 이미지의 전처리 과정을 거친 후 각 클래스 분류를 위해 대표 융선을 찾아 방향정보를 추출하고 이를 이용하여 5가지 클래스로 분류될 수 있도록 설계하였다. 좋은품질(Good)과 나쁜품질(Poor)의 데이터를 포함한 훈련집합을 사용하여 각 클래스별로 학습된 마코프 모델은 임의의 지문이미지 분류시 높은 분류율을 보였다. 또한 기존의 구조적 접근방법에 비하여 다양한 품질의 지문이미지의 방향성 정보를 이용한 확률론적 방법이기 때문에 예외적인 지문이미지 분류시 잘 적용될 수 있다.

• The Korean Journal of Applied Statistics
• /
• v.21 no.6
• /
• pp.959-967
• /
• 2008

The purpose of this paper is to suggest a discrete feature vector, robust in various levels of noisy environment and inexpensive in computation, for detection of speech segments and is to show such properties of the feature with real speech data. The suggested feature is one dimensional vector which represents slope of short term energies and is discretized into three values to reduce computational burden of computations in HMM. In experiments with speech data, the method with the suggested feature vector showed good performance even in noisy environments.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2013.11a
• /
• pp.1354-1357
• /
• 2013

최근 다양한 센서들이 일상생활에 활용되어, 일정한 환경에서 사람의 행동을 분류하고 인식하기 위한 연구들이 활발하게 진행되고 있다. 본 연구에서는 2개의 진동센서 값과 1개의 적외선 센서 값을 은닉 마코프 모델에 적용하여 침대 위에 있는 사람의 3가지 행동유형-눕기, 뒤척임, 일어나기-을 분류하고자 한다. 3개 센서 값의 특징들을 기초로 은닉 마코프 모델에 학습시키고, 특징집합과 학습 데이터량을 변화시키면서 사람의 행동유형에 대한 인식 실험을 수행하였다. 특징 개수 혼합에 따른 인식률의 차이는 거의 없는 것으로 나타났으나, 학습 데이터량을 증가시켜 가면서 수행한 실험에서는 인식률이 평균 78.127%로 향상되는 성과를 거두었다.

• Communications for Statistical Applications and Methods
• /
• v.15 no.2
• /
• pp.293-302
• /
• 2008

In this paper we propose a new feature, average power, for speech segments extraction with hidden Markov models, which is based on mel frequencies of speech signals. The average power is compared with the mel frequency cepstral coefficients, MFCC, and the power coefficient. To compare performances of three types of features, speech data are collected for words with explosives which are generally known hard to be detected. Experiments show that the average power is more accurate and efficient than MFCC and the power coefficient for speech segments extraction in environments with various levels of noise.

• KIPS Transactions on Software and Data Engineering
• /
• v.2 no.10
• /
• pp.723-730
• /
• 2013

This paper presents the design of an arm gesture recognition system using Kinect sensor. A variety of methods have been proposed for gesture recognition, ranging from the use of Dynamic Time Warping(DTW) to Hidden Markov Models(HMM). Our system learns a unique HMM corresponding to each arm gesture from a set of sequential skeleton data. Whenever the same gesture is performed, the trajectory of each joint captured by Kinect sensor may much differ from the previous, depending on the length and/or the orientation of the subject's arm. In order to obtain the robust performance independent of these conditions, the proposed system executes the feature transformation, in which the feature vectors of joint positions are transformed into those of angles between joints. To improve the computational efficiency for learning and using HMMs, our system also performs the k-means clustering to get one-dimensional integer sequences as inputs for discrete HMMs from high-dimensional real-number observation vectors. The dimension reduction and discretization can help our system use HMMs efficiently to recognize gestures in real-time environments. Finally, we demonstrate the recognition performance of our system through some experiments using two different datasets.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.52 no.8
• /
• pp.97-105
• /
• 2015

Content-adaptive steganography methods embed secret messages in hard-to-model regions of covers such as complicated texture or noisy area. Content-adaptive steganalysis methods often need high dimensional features to capture more subtle relationships of local dependencies among adjacent pixels. However, these methods require many computational complexity and depend on the location of hidden message and the exploited distortion metrics. In this paper, we propose an improved steganalysis method for content-adaptive steganography to enhance detection rate with small number features. We first show that the features form the difference between DCT coefficients are useful for analyzing the content-adaptive steganography methods, and present feature extraction mehtod using first-order Markov probability for the the difference between DCT coefficients. The extracted features are used as input of ensemble classifier. Experimental results show that the proposed method outperforms previous schemes in terms of detection rates and accuracy in spite of a small number features in various content-adaptive stego images.

• Journal of Biomedical Engineering Research
• /
• v.25 no.3
• /
• pp.217-225
• /
• 2004

In this paper, a new automatic classification method for the normal EEC and schizophrenia EEC using hidden Markov model(HMM) is proposed. We used the feature parameters which are the variance for statistical stationary interval of the EEC and power spectrum ratio of the alpha, beta, and theta wave. The results were shown that high classification accuracy of 90.9％ in the case of normal person, and 90.5％ in the case of schizophrenia patient. It seems that proposed classification system is more efficient than the system using complicate signal processing process. Hence, the proposed method can be used at analysis and classification for complicated biosignal such as EEC and is expected to give considerable assistance to clinical diagnosis.