• KIISE Transactions on Computing Practices
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• v.20 no.10
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• pp.549-554
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• 2014

Handwritten character recognition data is usually imbalanced because it is collected from the natural language sentences written by different writers. The imbalanced data can cause seriously negative effect on the performance of most of machine learning algorithms. But this problem is typically ignored in handwritten character recognition, because it is considered that most of difficulties in handwritten character recognition is caused by the high variance in data set and similar shapes between characters. We propose the oversampling-based ensemble learning methods to solve imbalanced data problem in handwritten character recognition and to improve the recognition accuracy. Also we show that proposed method achieved improvements in recognition accuracy of minor classes as well as overall recognition accuracy empirically.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.316-321
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• 2017

We analyze the online Hangul handwriting recognition problem (HHR) and present solutions based on recurrent neural networks. The solutions are organized according to the three kinds of sequence labeling problem - sequence classifications, segment classification, and temporal classification, with additional consideration of the structural constitution of Hangul characters. We present a stacked gated recurrent unit (GRU) based model as the natural HHR solution in the sequence classification level. The proposed model shows 86.2% accuracy for recognizing 2350 Hangul characters and 98.2% accuracy for recognizing the six types of Hangul characters. We show that the type recognizing model successfully follows the type change as strokes are sequentially written. These results show the potential for RNN models to learn high-level structural information from sequential data.

• Korean Journal of Cognitive Science
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• v.11 no.2
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• pp.69-78
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• 2000

Originally the Interactive Activation Model(IAM) was developed to explain World Superiority Effect(WSE) in the English words. It is known that there is a similar phenomena in Korean characters. In other words people perceive a grapheme better when it is presented as a component of a character than when it is presented alone. We modified the original IAM to explain the Character Superiority Effect(CSE) for Korean characters. However it is also reported that the degree of CSE for Korean characters varies depending on the type of the character. Especially a component between components was reported to be hard to perceive even though it is in a context. It was supposed that this special phenomenon exists for CSE of Korean characters because Korean character is a two-dimensional composition of components(graphemes). And we could explain this phenomenon by introducing weights for the input stimulus which are calculated by taking into account the two-dimensional shape of the character.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.859-861
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• 2015

생산 기술이 발전함에 따라 제품의 생산량이 증가하고 컴퓨터 비전을 통한 제품의 양/불 판단 기술의 필요성이 증가하고 있다. 제품의 양/불 판단은 그 정확도가 중요하며, 동시에 빠른 검사를 위한 신속성이 요구된다. 기존 연구들에서 다양한 금속성 제품에 대한 양/불 판단과 각인된 글자에 대한 양/불 판단을 수행하는 연구가 지속되어 왔으나 자동차 에어백 부품 중 하나인 Upper Housing의 양/불을 판단하는 알고리즘은 부재하다. 본 논문에서는 Upper Housing에 대해 각인 문자의 양/불을 판정하는 알고리즘을 제안한다. 먼저 영상에서 기준점이 되는 원을 찾는 것부터 시작하여, 기준점을 기반으로 특정 각도로 회전시켜 미리 수집한 글자 이미지와의 템플릿 매칭을 통해 글자가 제대로 각인 되었는지를 판단한다. 실험에서는 에어백 부품에 대한 검사 장치에서 촬영한 동영상에 대하여 제안한 알고리즘을 적용하였고, 그 결과 높은 정확도로 글자를 검출할 수 있음을 확인하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.549-551
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• 2006

Vehicle License Plate Recognition System reads information from vehicles license plate using image detection devices. Of many applications provided by Vehicle License Plate Recognition System, some, such as speed enforcing system, can be problematic when the system incorrectly scans letters or numbers from a vehicle's license plate. Using Cautious Classifier avoids such problems by discarding the scanned information when the confidence level is doubted to be low. This study develops the License Plate Recognition System using Cautious Classifier and investigates effectiveness of applying the Weighted Instance Method to improve the performance of Cautious Classifier.

• Journal of the Korea Society of Computer and Information
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• v.15 no.6
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• pp.29-35
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• 2010

While diversification of the use of video in the prevalence of cheap video equipment, augmented reality can print additional real-world images and video image. Although many recent advent augmented reality techniques, currently attempting to correct the character recognition is performed. In this paper characters marked with a visual marker recognition, and the color to match the marker color of the characters finds. And, it was shown on the screen by the character recognition. In this paper, by applying the phoneme pattern segmentation algorithm by the horizontal projection, we propose to segment the phoneme to match the six types of Hangul representation. Throughout the experiment sample of phoneme segmentation using augmented reality showed proceeding result at each step, and the experimental results was found to be that detection rate was above 90%.

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.25-30
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• 2000

Hangul is regarded as one of the difficult character set due to the large number of classes and the shape similarity among different characters. Most of the conventional researches attempted to recognize the 2,350 characters which are popularly used, but this approach has a problem or low recognition performance while it provides a generality. On the contrary, recognition of a small character set appearing in specific fields like postal address or bank checks is more practical approach. This paper describes a research for recognizing the handwritten Hangul characters appearing in monetary fields. The modular neural network is adopted for the classification and three kinds of feature are tested. The experiment performed using standard Hangul database PE92 showed the correct recognition rate 91.56%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.625-628
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• 2001

In this paper, it is shown that the car number plate are recognized more efficiently by using Fuzzy-ARTM AP. We use the location information of characters in the car number plate area and the color intensity difference between the character region and the background region int the tar number plate area. For segmented plate region, the car plate region is extracted by deciding the X-axis region composed by horizontal histogram and the Y-axis region composed by the variance histogram of vertical histogram. Our method then directly recognizes the extracted character region by using Fuzzy-ARTMAP neural network.

• Journal of Korea Society of Industrial Information Systems
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• v.6 no.2
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• pp.16-22
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• 2001

In this paper we mose a new scheme for recognition of deformed letters by extracting feature vectors based on Gibbs distributions which are well suited for representing the spatial continuity. The extracted feature vectors are comprised of 2-D conditional moments which are invariant under translation, rotation, and scale of an image. The Algorithm for pattern recognition of deformed letters contains two parts: the extraction of feature vector and the recognition process. (i) We extract feature vector which consists of an improved 2-D conditional moments on the basis of estimated conditional Gibbs distribution for an image. (ii) In the recognition phase, the minimization of the discrimination cost function for a deformed letters determines the corresponding template pattern. In order to evaluate the performance of the proposed scheme, recognition experiments with a generated document was conducted. on Workstation. Experiment results reveal that the proposed scheme has high recognition rate over 96%.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.1000-1003
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• 2020

본 논문은 기계학습 기반 온라인 한글 필기 인식 시스템의 첫 구현 결과를 담고 있다. 한글의 글자는 최소한 하나의 모음을 포함하고 있으며, 이 모음은 대개 직선으로 필기한다는 사전 지식을 활용하여 인식에 적용하고자 한다. 이를 위해 사용자가 온라인으로 필기하면 획 데이터를 획득하여 중성에 해당하는 모음을 찾는 알고리즘을 개발하였다. 제안한 알고리즘에서는, 우선 필기한 글자를 포함하는 사각형 R과 각 획을 둘러싸는 사각형 SR을 생성한 후, 직선을 판별하고, 이 직선들이 모음을 구성하는 후보군을 찾는 과정으로 구성되어 있다. 아직 초기 연구이므로, 다양한 경우에 대한 분석이나 실험 결과는 없지만, 이를 활용하여 온라인 필기 인식 모델에 적용하여 인식 성능을 높이기 위한 추후 연구의 기반으로 활용하고자 한다.