• 한국멀티미디어학회논문지
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• 제24권11호
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• pp.1472-1480
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• 2021

Image stacking technique is one of the key techniques for complex surface reconstruction. The process includes sample collection, image processing, algorithm editing, surface reconstruction, and finally reaching reliable conclusions. Since this experiment is based on laser scanning confocal microscope to collect the original contour information of the sample, it is necessary to briefly introduce the relevant principle and operation method of laser scanning confocal microscope. After that, the original image is collected and processed, and the data is expanded by interpolation method. Meanwhile, several methods of surface reconstruction are listed. After comparing the advantages and disadvantages of each method, one-dimensional interpolation and volume rendering are finally used to reconstruct the 3D model. The experimental results show that the final 3d surface modeling is more consistent with the appearance information of the original samples. At the same time, the algorithm is simple and easy to understand, strong operability, and can meet the requirements of surface reconstruction of different types of samples.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2010년도 추계학술발표대회
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• pp.1118-1121
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• 2010

With the advent of cell phone digital cameras, and sophisticated photo editing software, digital images can be easily manipulated and altered. Although good forgeries may leave no visual clues of having been tampered with, they may, nevertheless, alter the underlying statistics of an image. Most digital camera equipped in cell phones employ a single image sensor in conjunction with a color filter array (CFA), and then interpolates the missing color samples to obtain a three channel color image. This interpolation introduces specific correlations which are likely to be destroyed when tampering with an image. We quantify the specific correlations introduced by CFA interpolation, and describe how these correlations, or lack thereof, can be automatically detected in any portion of an image. We show the efficacy of this approach in revealing traces of digital tampering in lossless and lossy compressed color images interpolated with several different CFA algorithms in test cell phones.

• 정보보호학회논문지
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• 제33권4호
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• pp.671-685
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• 2023

인공지능이 이미지 편집 기술에 적용되어 조작 흔적이 거의 없는 고품질 이미지를 생성할 수 있게 되었다. 그러나 이러한 기술들은 거짓 정보 유포, 증거 인멸, 사실 부인 등의 범죄 행위에 악용될 수 있기 때문에 이에 대응하기 위한 방안이 필요하다. 본 연구에서는 이미지 조작을 탐지하기 위해 이미지 파일 분석과 모바일 포렌식 아티팩트 분석을 수행한다. 이미지 파일 분석은 조작된 이미지의 메타데이터를 파싱하여 Reference DB와 비교분석을 통해 조작여부를 탐지하는 방법이다. Reference DB는 이미지의 메타데이터에 남는 조작 관련 아티팩트를 수집하는 데이터베이스로서, 이미지 조작을 탐지하는 기준이 된다. 모바일 포렌식 아티팩트 분석은 이미지 편집 도구와관련된 패키지를 추출하고 분석하여 이미지 조작을 탐지하도록 한다. 본 연구에서 제안하는 방법론은 기존의 그래픽적 특징기반 분석의 한계를 보완하고, 이미지 처리 기법과 조합하여 오탐을 줄일 수 있도록 한다. 연구 결과는 이러한 방법론이 디지털 포렌식 조사 및 분석에 유의미하게 활용될 수 있음을 보여준다. 또한, 조작된 이미지 데이터셋과 함께 이미지 메타데이터 파싱 코드와 Reference DB를 제공하여 관련 연구에 기여하고자 한다.

• 한국컴퓨터그래픽스학회논문지
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• 제20권3호
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• pp.1-8
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• 2014

스마트폰의 전면 및 후면 카메라를 이용하여 동시에 획득한 전경 이미지와 배경 이미지에서, 전경 이미지의 일부분인 전경 물체를 추출하여 배경 이미지에 합성하는 방법을 제시한다. 최근의 고사양 스마트폰은 대개 두 개의 카메라를 가지고 있고, 사진을 촬영하는 과정에서 미리보기 화면을 제공한다. 전면 카메라로부터 전경 이미지를 획득하는 과정에서 미리보기 화면의 비디오에 대한 옵티컬 플로우를 이용하여 전경 물체를 추출한다. 추출된 전경 물체와 배경 화면을 단순히 합성한 후, 전경 물체와 배경화면의 경계에서 가중치 경계 블렌딩을 이용하여 시각적으로 부드러운 경계를 갖는 합성을 수행한다. 화소 수준의 조밀한 옵티컬 플로우의 계산은 고사양의 스마트폰에서도 상당히 느리기 때문에, 전경 물체 추출을 위한 마스크의 계산을 저해상도에서 수행하여 계산시간을 크게 절약할 수 있다. 실험적 결과에 의하면 제안하는 방법은 더 적은 계산 시간을 사용하며, 널리 사용되는 Poisson 이미지 합성 방법에 비하여 시각적으로 더 우수한 결과를 얻을 수 있다. 제안하는 방법은 Poisson 이미지 합성 방법에서 자주 관찰되는 색 번짐 결점을 가중치 경계 블렌딩을 이용하여 제한적인 수준에서 극복할 수 있다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권12호
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• pp.4326-4344
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• 2021

The SinGAN is one of generative adversarial networks that can be trained on a single nature image. It has poor ability to learn more global features from nature image, and losses much local detail information when it generates arbitrary size image sample. To solve the problem, a non-linear function is firstly proposed to control downsampling ratio that is ratio between the size of current image and the size of next downsampled image, to increase the ratio with increase of the number of downsampling. This makes the low-resolution images obtained by downsampling have higher proportion in all downsampled images. The low-resolution images usually contain much global information. Therefore, it can help the model to learn more global feature information from downsampled images. Secondly, the attention mechanism is introduced to the generative network to increase the weight of effective image information. This can make the network learn more local details. Besides, in order to make the output image more natural, the TVLoss function is introduced to the loss function of SinGAN, to reduce the difference between adjacent pixels and smear phenomenon for the output image. A large number of experimental results show that our proposed model has better performance than other methods in generating random samples with fixed size and arbitrary size, image harmonization and editing.

• 제어로봇시스템학회논문지
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• 제9권10호
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• pp.844-851
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• 2003

We introduces a development result of semi-automatic karyotyping system using image processing method to improve a long time working of the manual method and 5% error of traditional automatic karyotying system for analyzing karyotying. The karyotyping procedures have many routine tasks such as searching metaphases, taking pictures, developing, editing, etc. There are several automatic karyotyping systems in order to reduce the task in advanced countries. However, they are very expensive, applicable to only human chromosome, and have too many functions to use easily. This paper takes aim at high quality image resolution and development of interface that can adjust brightness and contrast of image on-line. The system can be applied to animal and plants as well as human's chromosome. The system developed in this paper is applied to pig and human. The effectiveness of the system is proved by hospitals in Korea.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2014년도 추계학술발표대회
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• pp.520-522
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• 2014

Due to the availability of easy-to-use and powerful image editing tools, the authentication of digital images cannot be taken for granted and it gives rise to non-intrusive forgery detection problem because all imaging devices do not embed watermark. Forgery detection plays an important role in this case. In this paper, an effective framework for passive-blind method for copy-move image forgery detection is proposed, based on Gabor filter which is robust to illumination, rotation invariant, robust to scale. For the detection, the suspicious image is selected and Gabor wavelet is applied from whole scale space and whole direction space. We will extract the mean and the standard deviation as the texture features and feature vectors. Finally, a distance is calculated between two textures feature vectors to determine the forgery, and the decision will be made based on that result.

• 한국멀티미디어학회논문지
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• 제21권7호
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• pp.764-771
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• 2018

In this paper, we propose a high-quality image acquisition algorithm using only a single image, which the high-quality image is normally referred as HDR ones. In order to acquire the HDR image, conventional methods need many images having different exposure values at the same scene and should delicately adjust the color values for a bit-expansion or an exposure fusion. Thus, they require considerable calculations and complex structures. Therefore, the proposed algorithm suggests a completely new approach using one image for the high-quality image acquisition by applying statistical difference and histogram manipulation, or histogram specification, techniques. The techniques could control the pixel's statistical distribution of the input image into the desired one through the local and the global modifications, respectively. As the result, the quality of the proposed algorithm is better than those of conventional methods implemented in commercial image editing softwares.

• Imaging Science in Dentistry
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• 제33권3호
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• pp.151-159
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• 2003

Purpose: The purpose of this study is to evaluate the effectiveness and usefulness of newly developed personal computer-based software to eliminate the linear artifacts by the metal restorations. Materials and Methods: A 3D CT image was conventionally reconstructed using ADVANTAGE WINDOWS 2.0 3D Analysis software (GE Medical System, Milwaukee, USA) and eliminated the linear artifacts manually. Next, a 3D CT image was reconstructed using V-works 4.0/sup TM/(Cybermed Inc., Seoul, Korea) and the linear artifacts eliminated manually in the axial images by a skillful operator using a personal computer. A 3D CT image was reconstructed using V-works 4.0/sup TM/(Cybermed Inc., Seoul, Korea) and the linear artifacts were removed using a simplified algorithm program to eliminate the linear artifacts automatically in the axial images using a personal computer, abbreviating the manual editing procedure. Finally, the automatically edited reconstructed 3D images were compared to the manually edited images. Results and Conclusion: We effectively eliminated the linear artifacts automatically by this algorithm, not by the manual editing procedures, in some degree. But programs based on more complicated and accurate algorithms may lead to a nearly flawless elimination of these linear artifacts automatically.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.137-143
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• 2005

Desktop PC에 IEEE1394(firewire) 장착의 대중화로 인하여 Non-Linear 비디오 편집이 대중화되고 있으며, DVD-RW의 가격인하로 인해 DVD라는 저장매체는 현 시대를 대표하는 영상저장매체로서 자리 잡고 있다. 그러나 일반인들이 DVD를 Authoring 하는데 있어 고화질 영상의 DVD를 제작하는 Process에 대한 연구 자료가 없는 실정이다. 따라서 본 논문에서는 일반적으로 많이 쓰이고 있는 Desktop PC의 대표적인 영상편집 소프트웨어인 Avid Xpress DV와 Adobe Premiere Pro를 이용하여 영상을 캡처(Capture) 받고, Adobe Encore를 이용한 Authoring으로 영상의 디지털화 과정에서 일어나는 화질 및 Export Data를 비교분석하여 Desktop PC에서의 고화질을 유지할 수 있는 DVD Authoring Process를 제안하고자 한다.