• Journal of KIISE:Software and Applications
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• v.29 no.4
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• pp.235-247
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• 2002

For an efficient indexing and retrieval of digital video data, research on video caption extraction and recognition is required. This paper proposes methods for extracting artificial captions from video data and enhancing their image quality for an accurate Hangul and English character recognition. In the proposed methods, we first find locations of beginning and ending frames of the same caption contents and combine those multiple frames in each group by logical operation to remove background noises. During this process an evaluation is performed for detecting the integrated results with different caption images. After the multiple video frames are integrated, four different image enhancement techniques are applied to the image: resolution enhancement, contrast enhancement, stroke-based binarization, and morphological smoothing operations. By applying these operations to the video frames we can even improve the image quality of phonemes with complex strokes. Finding the beginning and ending locations of the frames with the same caption contents can be effectively used for the digital video indexing and browsing. We have tested the proposed methods with the video caption images containing both Hangul and English characters from cinema, and obtained the improved results of the character recognition.

• Journal of KIISE:Software and Applications
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• v.31 no.9
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• pp.1142-1149
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• 2004

Motion Estimation(ME) has been developed to reduce temporal redundancy in digital video signals and increase data compression ratio. ME is an Important part of video encoding systems, since it can significantly affect the output quality of encoded sequences. However, ME requires high computational complexity, it is difficult to apply to real time video transmission. for this reason, motion estimation algorithms with low computational complexity are viable solutions. In this paper, we present an efficient method with low computational complexity based on spatial and temporal correlations of motion vectors. The proposed method uses temporally and spatially correlated motion information, the motion vector of the block with the same coordinate in the reference frame and the motion vectors of neighboring blocks around the current block in the current frame, to decide the search pattern and the location of search starting point adaptively. Experiments show that the image quality improvement of the proposed method over MVFAST (Motion Vector Field Adaptive Search Technique) and PMVFAST (Predictive Motion Vector Field Adaptive Search Technique) is 0.01～0.3(dB) better and the speedup improvement is about 1.12～l.33 times faster which resulted from lower computational complexity.

• The Journal of the Korea Contents Association
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• v.10 no.8
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• pp.95-103
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• 2010

Raw files record luminance values corresponds to each pixel of a digital camera sensor. In digital imaging, controlling exposure to capture the first highlight stop is important on linear-distribution of raw file characteristic. This study sought to verify the efficiency of ETTR method and found the optimum over-exposure amount to maintain the first highlight stop to be the largest number of levels. This was achieved by over-exposing a scene with a raw file and converting it to under-exposure in a raw file converting software. Our paper verified the efficiency of ETTR by controlling the exposure range and ISOs. Throughout the results, if exposure increases gradually 6 steps, dynamic range is also increased. And it shows that the optimized exposure value is around + $1\frac{2}{3}$ stop over compared to the normal exposure with the high ISOs simultaneously. We compared visual noise value at $1\frac{2}{3}$ stop to the normal exposure visual noise. Based on the normal exposure's visual noise, we can confirm that visual noise decrement is increased by increasing ISOs. In this experimental result, we confirm that overexposure about + $1\frac{2}{3}$ stop is the optimum value to make the widest dynamic range and lower visual noise in high ISOs. Based on the study results, we can provide the effective ETTR information to consumers and manufacturers. This method will contribute to the optimum image performance in maximizing dynamic range and minimizing noise in a digital imaging.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.7
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• pp.319-326
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• 2016

Given the attributes of mobile apps that shorten the time to make purchase decisions while enabling easy purchase cancellations, usability can be regarded to be a highly prioritized quality attribute among the diverse quality attributes that must be provided by mobile apps. With that backdrop, mobile app developers have been making great effort to minimize usability hampering elements that degrade the merchantability of apps in many ways. Most elements that hamper the convenience in use of mobile apps stem from those potential errors that occur when GUIs are designed. In our previous study, we have proposed a technique to analyze the usability of mobile apps using user behavior logs. We proposes a technique to detect usability hampering elements lying dormant in mobile apps' GUI models by expressing user behavior logs with finite state models, combining user behavior models extracted from multiple users, and comparing the combined user behavior model with the expected behavior model on which the designer's intention is reflected. In addition, to reduce the burden of the repeated test operations that have been conducted by existing developers to detect usability errors, the present paper also proposes a mobile usability error detection automation tool that enables automatic application of the proposed technique. The utility of the proposed technique and tool is being discussed through comparison between the GUI issue reports presented by actual open source app developers and the symptoms detected by the proposed technique.

• Journal of KIISE:Software and Applications
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• v.31 no.3
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• pp.332-342
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• 2004

With the explosive growth of information in our real life, information filtering is quickly becoming a popular technique for reducing information overload. Information filtering technique is divided into two categories: content-based filtering and collaborative filtering (or social filtering). Content-based filtering selects the information based on contents; while collaborative filtering combines the opinions of other persons to make a prediction for the target user. In this paper, we describe a new filtering approach that seamlessly combines content-based filtering and collaborative filtering to take advantages from both of them, where a technique using user profiles efficiently on the collaborative filtering framework is introduced to predict a user's preference. The proposed approach is experimentally evaluated and compared to conventional filtering. Our experiments showed that the proposed approach not only achieved significant improvement in prediction quality, but also dealt with new users well.

• The Journal of the Korea Contents Association
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• v.7 no.8
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• pp.134-141
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• 2007

In 3D animation rendering process, Although we can render the output as a movie file format, most productions use image sequences in their rendering pipelines. This Image Sequence rendering process is extremely important step in final compositing in movie industries. Although there are various type of making image rendering processes, TGA format Is one of most widely used bitmap file formats using in industries. People may ask TGA format is most suitable for in any case. As we know 3D softwares have their own image formats. so we need to testify on this. In this paper, we are going to focus on Alias' 3D package software called MAYA which we will analyze of compressing image sequence, Image quality, supporting Alpha channels in compositing, and Z-depth information. The purpose of this paper is providing to 3D Pipeline as a guideline about effective image sequence format.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.203-213
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• 2014

In this study, we proposed a new model with ISOIA (Insect Search by Observation based on Insect Appearance) method based on observation by insect appearance to improve user satisfaction, and compared it with the ISBC and ISOBC methods. In order to test these three insect search systems with AHP method, we derived three evaluation criteria for user satisfaction and three sub-evaluation criteria by evaluation criterion. In the ecological environment, non-experts need insect search systems to identify insect species and to get u-Learning contents related to the insects. To assist the public the non-experts, ISBC (Insect Search by Biological Classification) method based on biological classification to search insects and ISOBC (Insect Search by Observation based on Biological Classification) method based on the inference that identifies the observed insect through observation according to biological classification have been provided. In the test results, we found the order of priorities was ISOIA, ISOBC, and ISBC. It shows that the ISOIA system proposed in this study is superior in usage and quality compared with the previous insect search systems.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.131-136
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• 2005

In 3D animation rendering process, Although we can render the output as a movie file format, most productions use image sequences in their rendering pipelines. This Image Sequence rendering process is extremely important step in final compositing in movie industries. Although there are various type of making image rendering processes, TGA format is one of most widely used bitmap file formats using in industries. People may ask TGA format is most suitable for in any case. As we know 3D softwares have their own image formats. so we need to testify on this. In this paper, we are going to focus on Alias' 3D package software called MAYA which we will analyze of compressing image sequence, Image quality, supporting Alpha channels in compositing, and Z-depth Information. The purpose of this paper is providing to 3D Pipeline as a guideline about effective image sequence format.

• Journal of KIISE:Software and Applications
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• v.32 no.10
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• pp.974-983
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• 2005

In genetic algorithms with lotus-based encoding, static gene reordering is to locate the highly related genes closely together. It helps the genetic algorithms to create and preserve the schema of high-quality effectively. In this paper, we propose a static reordering framework for linear locus-based encoding. It differs from existing reorderings in that it is independent of problem-specific knowledge. It makes a complete graph where weights represent the interelationship between each pair of genes. And, it transforms the graph into a unweighted sparse graph by choosing the edges having relatively high weight. It finds a gene reordering by graph search method. Through the wide experiments about several problems, the method proposed in this paper shows significant performance improvement as compared with the genetic algorithm that does not rearrange genes.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.33-40
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• 2008

The application of OCR moves from traditional formatted documents to the web document and natural scene images. It is usual that the new applications use not only standard fonts of Myungjo and Godic but also various fonts. The conventional databases which have mainly been constructed with standard fonts have limitations in applying to the new applications. In this paper, we generate 243 image samples for each of 2350 Hangul character classes which differs in font size, quality, and resolution. Additionally each sample was varied according to binarization threshold and rotational transformation. Through this process 2187 samples were generated for each character class. Totally 5,139,450 samples constitutes the printed Hangul character database called the PHD08. In addition, we present the characteristics and recognition performance by an commercial OCR software.