• 수산해양기술연구
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• 제39권2호
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• pp.92-98
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• 2003

소너를 이용한 어군량 조사에서 자동화가 용이하고 고기의 분포상태에 관계없이 측정이 가능한 에코적분법에 관한 정량화법의 기초 연구로서, 소너 화상의 휘도를 2 승 적분하여 어군량을 정량화하고 이 값을 다른 어군량 지표와 비교, 분석한 결과를 요약하면 다음과 같다. 1. 휘도를 이용하여 작성한 에코그램으로부터 어군과 해저를 분명하게 식별하는 것이 가능하여 화상을 이용한 어군량의 정량화에 있어서 휘도는 유용한 정보이다. 2. 소너 화상으로부터 계수법에 의하여 얻어진 어군의 수는 픽셀 휘도의 2승 적분치에 정의 상관을 나타내었으나, 어군의 계수법은 어군의 규모에 관계하지 않고 어군을 계수하기 때문에 오차가 클것으로 판단되어 정량화법으로서는 좋은 방법이라 할 수 없다. 3. 면적측정법으로 계측된 어군면적은 픽셀 휘도의 2승 적분치에 비례하고 유의한 상관을 나타내었으므로, 어군량 지표로서 유용 가능하다고 판단된다. 4. 소너 화상의 휘도를 2 승 적분하여 얻어진 어군량 정보는 고기의 분포상태에 관계없이 측정이 가능하여 어군량을 정량화하는 방법으로서 유용할 것으로 판단된다.

• 컴퓨터교육학회논문지
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• 제11권5호
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• pp.57-66
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• 2008

본 논문에서는 낮은 해상도의 영상을 높은 해상도의 영상으로 보간하는 과정에서 각각의 픽셀에 대해 최적화된 매개변수를 적용하는 새로운 적응적 3차 회선 보간 기법을 제안한다. 기존의 3차 회선 보간 기법은 보간하려는 영상에 대해 동일한 매개변수를 적용하여 각 픽셀의 고유한 특성을 적응적으로 반영하지 못하였지만, 제안한 보간 기법은 픽셀의 정보에 따라 매개변수를 최적화하여 반영함으로써 주어진 영상을 고화질 영상으로 보간한다. 여러 가지 영상을 통해 본 논문에서 제안한 보간 기법과 기존에 알려진 보간 기법들을 비교하는 실험을 하였고, 도출된 실험 결과를 객관적인 지표로 제시하여 우수함을 입증하였다.

• 비파괴검사학회지
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• 제30권3호
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• pp.181-193
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• 2010

The paper presents an alternative way to classical stereocorrelation. First, 2D image processing of random patterns is described. Sub-pixel displacements are determined using phase analysis. Then distortion evaluation is presented. The distortion is identified without any assumption on the lens model because of the use of a grid technique approach. Last, shape measurement and shape variation is caught by fringe projection. Analysis is based on two pin-hole assumptions for the video-projector and the camera. Then, fringe projection is coupled to in-plane displacement to give rise to 3D measurement set-up. Metrological characterization shows a resolution comparable to classical (stereo) correlation technique ($1/100^{th}$ pixel). Spatial resolution seems to be an advantage of the method, because of the use of temporal phase stepping (shape measurement, 1 pixel) and windowed Fourier transform (in plane displacements measurement, 9 pixels). Two examples are given. First one is the study of skin properties; second one is a study on leather fabric. In both cases, results are convincing, and have been exploited to give mechanical interpretation.

• Journal of Information Processing Systems
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• 제14권3호
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• pp.666-679
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• 2018

The discrete wavelet transform (DWT) has good multi-resolution decomposition characteristic and its low frequency component contains the basic information of an image. Based on this, a fragile watermarking using the local binary pattern (LBP) and DWT is proposed for image authentication. In this method, the LBP pattern of low frequency wavelet coefficients is adopted as a feature watermark, and it is inserted into the least significant bit (LSB) of the maximum pixel value in each block of host image. To guarantee the safety of the proposed algorithm, the logistic map is applied to encrypt the watermark. In addition, the locations of the maximum pixel values are stored in advance, which will be used to extract watermark on the receiving side. Due to the use of DWT, the watermarked image generated by the proposed scheme has high visual quality. Compared with other state-of-the-art watermarking methods, experimental results manifest that the proposed algorithm not only has lower watermark payloads, but also achieves good performance in tamper identification and localization for various attacks.

• Journal of Information Processing Systems
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• 제15권1호
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• pp.34-46
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• 2019

A method for detecting foreign substances in mould based on scatter grams was presented to protect moulds automatically during moulding production. This paper proposes a wavelet transform foreign detection method based on Monte Carlo analysis mechanism to identify foreign objects in the tube. We use the Monte Carlo method to evaluate the image, and obtain the width of the confidence interval by the deviation statistical gray histogram to divide the image type. In order to stabilize the performance of the algorithm, the high-frequency image and the low-frequency image are respectively drawn. By analyzing the position distribution of the pixel gray in the two images, the suspected foreign object region is obtained. The experiments demonstrate the effectiveness of our approach by evaluating the labeled data.

• 정보저장시스템학회논문집
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• 제5권1호
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• pp.36-40
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• 2009

We describe the experimental realization of image system using wavefront coding in 3-Mega pixel mobile phone camera. We designed aspheric lens to extend the depth of field (DOF) using wavefront coding. In addition, through the aspheric lens and lens barrel manufacturing, we obtained a raw image from a camera module. In our method, the acquired images are restored in the spatial frequency domain using the proposed filter and the spatial frequency response (SFR) is calculated. The proposed filters are composed of image denoising filter using low band pass filter in frequency domain and restoration filter for image restoration. Finally, we achieve an enhanced image by super-resolution image processing. Visual examples are given to demonstrate the performance of the proposed filter.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권3호
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• pp.1224-1242
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• 2018

Aiming at motion analysis and compensation, it is essential to conduct motion detection with images. However, motion detection and tracking from low-altitude images obtained from an unmanned aerial system may pose many challenges due to degraded image quality caused by platform motion, image instability and illumination fluctuation. This research tackles these challenges by proposing a modified joint transform correlation algorithm which includes two preprocessing strategies. In spatial domain, a modified fuzzy edge detection method is proposed for preprocessing the input images. In frequency domain, to eliminate the disturbance of self-correlation items, the cross-correlation items are extracted from joint power spectrum output plane. The effectiveness and accuracy of the algorithm has been tested and evaluated by both simulation and real datasets in this research. The simulation experiments show that the proposed approach can derive satisfactory peaks of cross-correlation and achieve detection accuracy of displacement vectors with no more than 0.03pixel for image pairs with displacement smaller than 20pixels, when addition of image motion blurring in the range of 0~10pixel and 0.002variance of additive Gaussian noise. Moreover,this paper proposes quantitative analysis approach using tri-image pairs from real datasets and the experimental results show that detection accuracy can be achieved with sub-pixel level even if the sampling frequency can only attain 50 frames per second.

• 대한디지털의료영상학회논문지
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• 제9권1호
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• pp.7-15
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• 2007

고정식 초점형 격자가 적용된 비정질 실리콘 평판형 검출기에서 초점-격자간 중심변위와 두부 팬텀의 검출기내 위치 변위가 영상 특성에 미치는 영향을 조사하여, 디지털 의료영상 장비의 올바른 사용 방법을 제안하고자 한다. 고정식 초점형 격자를 적용한 비정질 실리콘 평판형 검출기에서 두부 팬텀을 사용하여 초점-격자간 중심 변위와 두부 팬텀의 위치 변위에 따라 영상을 획득 하였다. 획득된 영상을 NIH(Image J) 영상 분석 프로그램을 이용하여 동일 영역에서의 픽셀값(Pixel value), 히스토그램(Histogram), 도면형상(plot profile), 표면도(Surface plot)등을 분석하고, 표준 촬영 영상과 비교 하였다. 초점-격자간 측 방향 중심 변위와 초점-격자와 두부 팬텀의 이중 변위는 수평, 대각선으로 증가할수록 픽셀의 평균값과 표준편차값이 비례적으로 감소하였다. 또한 높은 픽셀값의 빈도수가 상당히 감소하여 영상의 대조도를 저하시켰고, 변위가 증가할수록 영상 왜곡현상도 증가하였다. 다음으로 두부 팬텀 위치 변위의 픽셀 평균값은 큰 변화가 없었으나 수평, 대각선으로 증가할수록 높은 픽셀값의 빈도수가 감소하는 양상을 보여 영상의 대조도가 저하 되었다. 디지털 검출기의 넓은 관용도와 후처리 능력은 영상의 화소 잡음이 증가하여도 방사선사들이 인지하지 못할 수 있다. 따라서 방사선사는 격자가 장착된 디지털 검출기에서 화소 잡음을 증가시키는 촬영 요인들을 정확히 인지하여 검사에 임해야 할 것이다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2019년도 춘계학술발표대회
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• pp.401-403
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• 2019

In this paper, we propose a generative adversarial networks (GAN) based text-to-image generating method. In many natural language processing tasks, which word expressions are determined by their term frequency -inverse document frequency scores. Word2Vec is a type of neural network model that, in the case of an unlabeled corpus, produces a vector that expresses semantics for words in the corpus and an image is generated by GAN training according to the obtained vector. Thanks to the understanding of the word we can generate higher and more realistic images. Our GAN structure is based on deep convolution neural networks and pixel recurrent neural networks. Comparing the generated image with the real image, we get about 88% similarity on the Oxford-102 flowers dataset.

• Journal of information and communication convergence engineering
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• 제13권4호
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• pp.264-269
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• 2015

The chest X-ray image cannot be focused in the same manner that optical lenses are and the resultant image generally tends to be slightly blurred. Therefore, the methods to improve the quality of chest X-ray image have been studied. In this paper, the inherent noises of the input images are suppressed by adding the Laplacian image to the original. First, the chest X-ray image using an Gaussian high pass filter and an optimal high frequency emphasis filter has shown improvements in the edges and contrast of flat areas. Second, using fuzzy logic_histogram equalization, each pixel of the chest X-ray image shows the normal distribution of intensities that are not overexposed. As a result, the proposed method has shown the enhanced edge and contrast of the images with the noise canceling effect.