• 한국정보전자통신기술학회논문지
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• 제10권2호
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• pp.147-153
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• 2017

텍스쳐를 효과적으로 표현하는 것은 컴퓨터 비전 분야에서 매우 중요한 과정이다. 효과적인 텍스쳐 표현을 통해 텍스쳐 분류나 텍스쳐 분할 등의 처리 성능을 향상시킬 수 있다. 가버 필터는 텍스쳐 표현을 위해 오랫동안 사용된 다해상도 스케일 기반의 방법이다. 가버 필터는 텍스쳐 분류나 분할에 높은 성능을 제공한다. 그러나 처리 과정의 연산량으로 인해 처리 시간이 매우 많이 소요되어 실제 응용에서는 사용하기 어려운 문제가 있다. 본 논문에서는 가버 필터와 유사하게 다해상도 스케일 기반으로 텍스쳐를 표현할 수 있는 새로운 특징 표현 방법을 제안한다. 제안한 방법은 주파수 공간에서 방향과 스케일을 기반으로 다해상도 스케일 기반으로 텍스쳐를 표현한다. 2가지 실험 영상 집합에 대해 분류 실험을 수행하여 제안한 특징의 유용성을 확인하였다. 가버 필터와 유사한 분류 성능을 제공하면서 처리 속도는 가버 필터의 5%이하로 줄일 수 있는 것을 확인하였다.

• Imaging Science in Dentistry
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• 제53권2호
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• pp.109-115
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• 2023

Purpose: The aim of this study was to evaluate changes in the trabecular bone through texture analysis and compare the texture analysis characteristics of different areas in patients with medication-related osteonecrosis of the jaw (MRONJ). Materials and Methods: Cone-beam computed tomographic images of 16 patients diagnosed with MRONJ were used. In sagittal images, 3 regions were chosen: active osteonecrosis(AO); intermediate tissue (IT), which presented a zone of apparently healthy tissue adjacent to the AO area; and healthy bone tissue (HT) (control area). Texture analysis was performed evaluating 7 parameters: secondary angular momentum, contrast, correlation, sum of squares, inverse moment of difference, sum of entropies, and entropy. Data were analyzed using the Kruskal-Wallis test with a significance level of 5%. Results: Comparing the areas of AO, IT, and HT, significant differences (P<0.05) were observed. The IT and AO area images showed higher values for parameters such as contrast, entropy, and secondary angular momentum than the HT area, indicating greater disorder in these tissues. Conclusion: Through texture analysis, changes in the bone pattern could be observed in areas of osteonecrosis. The texture analysis demonstrated that areas visually identified and classified as IT still had necrotic tissue, thereby increasing the accuracy of delimiting the real extension of MRONJ.

• 대한원격탐사학회지
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• 제23권2호
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• pp.103-111
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• 2007

지금까지 위성영상 정보 처리 분야에서는 분광정보를 이용한 영상분석과 시각적 해석 및 자동 분류에 대한 연구가 주로 수행되었으나, 최근에는 영상자료에서 시각적으로 나타나지 않는 특성이나 공간정보의 추출을 위한 여러 시도가 이루어지고 있다. 본 연구에서는 영상정보의 특성 추출기법인 텍스처 영상 생성기법과 웨이브릿 변환을 연계하여 웨이브릿 기반 텍스처 융합 영상에 대한 연구를 수행하였다. 또한 이러한 영상이 분류 정확도에 어떻게 기여하는 가를 분석하기 위한 적용 사례로 도심지 공간분석과 칼데라 주변지역의 지질학적 구조분석을 수행하였다 영상 분석 시 공간정보 활용을 위한 텍스처 영상 생성기법과 웨이브릿 기반 텍스처 융합 영상 생성기법을 사용하면 원본영상만을 사용하였을 때보다 높은 분류정확도를 보였다. 고해상도 영상을 사용한 도심지의 경우 원본영상에 텍스처영상과 웨이브릿 기반 텍스처 융합 영상을 모두 활용한 경우의 분류정확도가 가장 높은 값을 보였다. 이는 상세화소의 변화가 매우 중요한 도심지의 특성상, 세밀한 공간정보가 최대로 활용되었기 때문으로 해석되어진다. 또한 중 저해상도 영상을 사용한 지질학적 구조분석의 경우 원본영상에 텍스처 영상만을 활용한 경우가 가장 높은 분류정확도를 보였다. 이는 칼데라를 중심으로 한 비교적 크기가 큰 지질학적 구조 분석 시 고도변화와 지열분포 등의 정보가 적당히 단순화 될 필요가 있었기 때문인 것으로 해석된다. 따라서 이러한 기법들을 실제 연구에 적용하기 위해서는 연구의 목적과 위성영상의 해상도 등의 정보를 모두 고려하여 적절한 기법을 잘 적용하는 것이 중요하다.

• 한국전기전자재료학회논문지
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• 제16권10호
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• pp.938-945
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• 2003

We fabricated Ni-substrate for YBCO coated conductors and evaluated the effects of pressing and annealing temperature and time on texture. Ni substrate was fabricated by powder metallurgy technique and compacts were prepared by applying uniaxial or isostatic pressure. The texture of substrate made by applying cold isostatic pressure (CIP) was stronger than that by uniaxial pressure which we attribute to the fact that the CIP method provided higher density and more uniform density distribution. It was observed that the substrate annealed at 400 C showed both retained texture and recrystallized texture. On the other hand, the texture of substrate significantly improved at annealing temperature above 500 C, forming strong 4-fold symmetry, [111] II ND texture, and FWHM of 9∼10 . It is to be noted that the degree of texture was almost independent of annealing temperature (500∼1000 C) and annealing time(1∼54 min, at 1000 C). EBSD and AFM analysis indicated that 99% of grain boundaries was low angle grain boundary and RMS was approximately 3 nm, respectively. Development of strong cube texture and high fraction of low angle grain boundary of Ni-substrate made by powder metallurgy technique in our study is considered to be suitable for the application of YBCO coated conductors.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.14-16
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• 2004

Although there have been wide range of studies to characterize forest stands based upon spectral information of satellite image, it was not fully understood the texture information of forest stand using high resolution data. The objective of this study is to evaluate several texture measures for characterizing forest stand structure, such as species composition, diameter at breast height(DBH), stand density, and age. High resolution IKONOS satellite imagery data were acquired in August 200 lover the forested area near Ulsan, Korea. Primary forest types were plantation pine, mixed forest, and natural deciduous forest of stand age ranging from 10 to 50 years old. Several GLCM-based texture measures were compared with forest stand characteristics. In overall, a texture measure (contrast) calculated using red band were better to differentiate species and age group than other texture measures and near infrared bands.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1996년도 Proceedings International Workshop on New Video Media Technology
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• pp.23-28
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• 1996

Model-based coding is one of several approaches to very low bit rate image coding and it can be used in many applications such as image creation and virtual reality. However, its analysis and synthesis processes remain difficult, especially in the sense that the resulting synthesized image reveals some degradation in detailed facial components such as furrows around eyes and mouth. To solve the problem, a large number of methods have been proposed and the texture update method is one of them. In this paper, we investigate texture synthesis for model-based coding. In the update process of the proposed texture synthesis algorithm, texture information is stored in a memory and the decoder reuses it. With this method, the transmission bit rate for texture data can be reduced compared with the conventional method updating texture periodically.

• Investigative Magnetic Resonance Imaging
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• 제25권2호
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• pp.93-100
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• 2021

Purpose: (1) To evaluate the trabecular pattern at the femoral attachment of the posterior cruciate ligament (PCL) in patients with a PCL injury; (2) to analyze bone microarchitecture by applying gray level co-occurrence matrix (GLCM)-based texture analysis; and (3) to determine if there is a significant relationship between bone microarchitecture and posterior instability. Materials and Methods: The study included 96 patients with PCL tears. Trabecular patterns were evaluated on T2-weighted MRI qualitatively, and were evaluated by GLCM texture analysis quantitatively. The grades of posterior drawer test (PDT) and the degrees of posterior displacement on stress radiographs were recorded. The 96 patients were classified into two groups: acute and chronic injury. And 27 patients with no PCL injury were enrolled for control. Pearson's correlation coefficient and one-way ANOVA with Bonferroni test were conducted for statistical analyses. This protocol was approved by the Institutional Review Board. Results: A thick and anisotropic trabecular bone pattern was apparent in normal or acute injury (n = 57/61;93.4%), but was not prominent in chronic injury and posterior instability (n = 31/35;88.6%). Grades of PDT and degrees of posterior displacement on stress radiograph were not correlated with texture parameters. However, the texture analysis parameters of chronic injury were significantly different from those of acute injury and control groups (P < 0.05). Conclusion: The trabecular pattern and texture analysis parameters are useful in predicting posterior instability in patients with PCL injury. Evaluation of the bone microarchitecture resulting from altered biomechanics could advance the understanding of PCL function and improve the detection of PCL injury.

• Korean Journal of Radiology
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• 제22권11호
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• pp.1797-1808
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• 2021

Objective: To determine whether volumetric CT texture analysis (CTTA) using fully automatic tumor segmentation can help predict recurrence-free survival (RFS) in patients with intrahepatic mass-forming cholangiocarcinomas (IMCCs) after surgical resection. Materials and Methods: This retrospective study analyzed the preoperative CT scans of 89 patients with IMCCs (64 male; 25 female; mean age, 62.1 years; range, 38-78 years) who underwent surgical resection between January 2005 and December 2016. Volumetric CTTA of IMCCs was performed in late arterial phase images using both fully automatic and semi-automatic liver tumor segmentation techniques. The time spent on segmentation and texture analysis was compared, and the first-order and second-order texture parameters and shape features were extracted. The reliability of CTTA parameters between the techniques was evaluated using intraclass correlation coefficients (ICCs). Intra- and interobserver reproducibility of volumetric CTTAs were also obtained using ICCs. Cox proportional hazard regression were used to predict RFS using CTTA parameters and clinicopathological parameters. Results: The time spent on fully automatic tumor segmentation and CTTA was significantly shorter than that for semi-automatic segmentation: mean ± standard deviation of 1 minutes 37 seconds ± 50 seconds vs. 10 minutes 48 seconds ± 13 minutes 44 seconds (p < 0.001). ICCs of the texture features between the two techniques ranged from 0.215 to 0.980. ICCs for the intraobserver and interobserver reproducibility using fully automatic segmentation were 0.601-0.997 and 0.177-0.984, respectively. Multivariable analysis identified lower first-order mean (hazard ratio [HR], 0.982; p = 0.010), larger pathologic tumor size (HR, 1.171; p < 0.001), and positive lymph node involvement (HR, 2.193; p = 0.014) as significant parameters for shorter RFS using fully automatic segmentation. Conclusion: Volumetric CTTA parameters obtained using fully automatic segmentation could be utilized as prognostic markers in patients with IMCC, with comparable reproducibility in significantly less time compared with semi-automatic segmentation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
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• pp.313-319
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• 1999

The development of deformation texture in FCC polycystalline metals during rolling was simulated by the finite element analysis using a large-deformation, elaatic-plastic, rate-dependent polycrystalline model of crystal plasticity. Different plastic anisotropy due to different orientation of each crystal makes inhomogeneous deformation. Assuming plane strain compression condition, the simulation with a high rate sensitivity resulted in main component change from Dillamore at low rate sensitivity to Brass component.

• 대한가정학회지
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• 제23권3호
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• pp.49-53
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• 1985

The typical texture profile analysis of acorn flour gel was investigated with Instron univ. testing machine by two experimental designs, 3$\times$3 latin square and $3^{3}$factorial experiment. As the result, it was revealed that Latin square is a useful method to reduce the number of experiments, in the case of a negligible interaction.