Youngseop Kim

Efficient image retrieval using advanced SURF and DCD on mobile platform

As the amount of digital image continues to grow in usage, users are experiencing increased difficulty in finding specific images in the image collection. This paper proposes a novel image searching scheme that extracts the image feature using combination of ASURF (Advanced Speed-Up Robust Feature) and DCD (Dominant Color Descriptor). The system for mobile image searches runs in real-time on iPhone, and can be easily used to find a natural color image. To evaluate the proposed scheme, we assessed the performance of simulation in term of average precision and F-score on two image database, which is commonly used in the field of image retrieval. The experimental results revealed that the proposed algorithm exhibited a significant improvement of over 14.4 % in retrieval effectiveness, compared to open source OpenSURF. The main contribution of this paper is that the proposed approach achieves high accuracy and stability by using ASURF and DCD in searching for natural image on mobile platform.

JPEG's JPSearch Standard: Harmonizing Image Management and Search

Triggered by the rise of social networks, community-based image sharing platforms are emerging at an increasing rate. Currently, almost every repository offers a different interaction interface and metadata description format. Unfortunately, this prevents unified and efficient access to these repositories. Consequently, data exchange between systems is often cumbersome. In this context, ISO/IEC JTC1 SC29 WG1 (more commonly known as JPEG) initiated the JPSearch framework standardization, which aims to foster the interaction with and among image repositories. The standard focuses on three main cornerstones supporting repository synchronization, search and access, and image collection creation and maintenance. This article discusses the main concepts, parts, and achievements of the JPSearch framework and demonstrates its use through a set of substantial case studies.

Robust audio watermarking in wavelet domain using pseudorandom sequences

In this paper, we proposed digital watermarking algorithms for high quality audio to improve robustness of embedded watermark by adding spread spectrum. The watermark is embedded in each audio frame by adding a perceptually-shaped pseudo-random sequence. The proposed method realized digital audio watermarking technique that audience cannot perceive as a noise by inserting the watermark with using the psychoacoustic model.

Emotional Recognition from Facial Expression Analysis Using Bezier Curve Fitting

Extracting and understanding of emotion is of high importance for the interaction among human and machine communication systems. The most expressive way to display the humans emotion is through facial expression analysis. This paper presents and implements an automatic extraction and recognition method of facial expression and emotion from still image. To evaluate the performance of the proposed algorithm, we assess the ratio of success with emotionally expressive facial image database. Experimental results shows average 66% of success to analyze and recognize the facial expression and emotion. The obtained result indicates the good performance and enough to applicable to mobile environments.

Single reference super-resolution using inter-subband correlation of directional edge

We propose an efficient single reference superresolution system based on the discrete wavelet transform. We assume that the low-resolution image to be enhanced is the low-frequency subband of the high-resolution image to be reconstructed. We design a support vector machine synthesizing the high-frequency subband based on the inter-subband correlation of the directional edges. Experimental results of sample images show that the proposed system offers improvements in terms of both measured distortion and subjective appearance.

Low-Complexity Motion Estimation for H.264/AVC Through Perceptual Video Coding

This paper presents a low-complexity algorithm for an H.264/AVC encoder. The proposed motion estimation scheme determines the best coding mode for a given macroblock (MB) by finding motion-blurred MBs; identifying, before motion estimation, an early selection of MBs; and hence saving processing time for these MBs. It has been observed that human vision is more sensitive to the movement of well-structured objects than to the movement of randomly structured objects. This study analyzed permissible perceptual distortions and assigned a larger inter-mode value to the regions that are perceptually less sensitive to human vision. Simulation results illustrate that the algorithm can reduce the computational complexity of motion estimation by up to 47.16% while maintaining high compression efficiency.

Dielectric, pyroelectric properties, and morphotropic phase boundary in la-doped (1 - x)pb(mg1/3ta2/3)-xpbtio3 solid solution ceramics

Abstract Dielectric and pyroelectric properties of relaxor ferroelectric in the (1 - x)(Pbl-3y/2Lay)(Mg1/3Ta2/3)-xPbTiO3 (PMT-PT) solid solution series have been investigated. The dielectric constant and loss of ceramic samples were determined. The pyroelectric coefficient and spontaneous polarization were measured by the static Byer-Roundy method as a function of temperature for various compositions in the La-doped PMT-PT system. The position of the morphotropic phase boundary in PMT-PT appeared not to be affected by La2O3 addition. Lanthanum-doping resulted in a reduction of grain size and shifting of the Tc by about 25°C/mole% downward in the PMT-PT system. Dielectric constants and pyroelectric coefficients for La-doped PMT-PT are much larger compared to the undoped PMT-PT system. Further additions of La2O3 could be used to shift the Tc downward without significantly changing the dielectric behavior. In the present study no clear morphotropic phase boundary (MPB) has been identified. A two-phase region...

Dielectric, piezoelectric and pyroelectric properties of Pb(Mg1/3Ta2/3)O3-PbTiO3-BaTiO3 system

Abstract Dielectric, piezoelectric and pyroelectric response of selected compositions from this solid solution system have been investigated as a function of PT and BT content for compositions near the morphotropic phase boundary (PMT-PT). The dielectric constant and loss of poled samples were determined. Pyroelectric coefficient, electromechanical coupling factor and piezoelectric d33 constant were observed on various compositions. The transition temperature and peak temperature of the ceramics decreased gradually with the addition of BT. The addition of BT to the PMT-PT system results in slightly reduced dielectric constant. Further addition of BT could be used to shift the Tc downward without significantly changing the electrical behavior.

Dielectric, piezoelectric and pyroelectric properties in the (1–x)Pb(Mg0.7Zn0.3)1/3Nb2/3O3-xPbTiO3 system

Abstract Dielectric, piezoelectric and pyroelectric properties of relaxor ferroelectric in the (1–x)Pb(Mg0.7Zn0.3)1/3Nb2,3O3–xPbTiO3 (PMZN-PT) solid solution series have been investigated. The diel...

Efficient Compression Algorithm for H.264/AVC Intra-prediction Using an Activity Map

H.264/AVC, the international video coding standard developed by ITU-T VCEG and ISO/IEC MPEG, is known to be more efficient than other standards. Higher compression is provided with the parameter block mode of H.264/AVC, but due to its low compression efficiency, researchers tend to ignore the algorithms intra-prediction coding capability. This study examined this overlooked aspect to determine its impact on compression efficiency and identify potential adverse effects. This paper proposes a novel algorithm to boost efficiency using an activity map for the pixel unit of respective prediction block in conjunction with specific thresholds. Experimental results reveal that compared to the existing H.264/AVC algorithm, the proposed algorithm shows a significant improvement of over 0.35% in the compression efficiency without any increase in overall encoding time and PSNR complexity.