• Title/Summary/Keyword: image assessment

Search Result 1,134, Processing Time 0.034 seconds

Quality Analysis of SAR Image

  • Lee, Young-Ran;Kwak, Sung-Hee;Shin, Dong-Seok;Park, Won-Kyu
    • Proceedings of the KSRS Conference
    • /
    • 2003.11a
    • /
    • pp.628-630
    • /
    • 2003
  • Synthetic Aperture Radar(SAR) is an active microwave instrument that performs high-resolution observation under almost all weather condition. Research and algorithms have been proposed to process radar signal and to increase the quality of SAR products. In fact, many complicated steps are involved in order to generate a SAR image product. The purpose of this paper is to derive quality assessment procedures and define important test parameters in each procedure inside a SAR processor. Thus those test parameter values indicate the quality of SAR image products and verify the processor's performance. Moreover, required procedures to correct and handle errors which are indicated during the assessment are also presented.

  • PDF

New Finger-vein Recognition Method Based on Image Quality Assessment

  • Nguyen, Dat Tien;Park, Young Ho;Shin, Kwang Yong;Park, Kang Ryoung
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.7 no.2
    • /
    • pp.347-365
    • /
    • 2013
  • The performance of finger-vein recognition methods is limited by camera optical defocusing, the light-scattering effect of skin, and individual variations in the skin depth, density, and thickness of vascular patterns. Consequently, all of these factors may affect the image quality, but few studies have conducted quality assessments of finger-vein images. Therefore, we developed a new finger-vein recognition method based on image quality assessment. This research is novel compared with previous methods in four respects. First, the vertical cross-sectional profiles are extracted to detect the approximate positions of vein regions in a given finger-vein image. Second, the accurate positions of the vein regions are detected by checking the depth of the vein's profile using various depth thresholds. Third, the quality of the finger-vein image is measured by using the number of detected vein points in relation to the depth thresholds, which allows individual variations of vein density to be considered for quality assessment. Fourth, by assessing the quality of input finger-vein images, inferior-quality images are not used for recognition, thereby enhancing the accuracy of finger-vein recognition. Experiments confirmed that the performance of finger-vein recognition systems that incorporated the proposed quality assessment method was superior to that of previous methods.

Accurate quantitative assessment of grouting efficiency in fractured rocks by evaluating the aperture sizes of fractures (절리암반내 그라우팅 성과에 대한 정량적인 판단기법 개발)

  • 김중열;김유성;김형수;백건하;김기석
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2002.03a
    • /
    • pp.695-702
    • /
    • 2002
  • Groundwater flow is primarily influenced by the presence of fractures, functioning as conduits. To block the flow, grouting operation is commonly used. Thereby the fractures are then expected to be sealed, which will add to enhance the shear strength in rock. This far, regarding the assessment of grouting efficiency, however, there's been a considerable uncertainty That is, several geophysical methods of high resolution such as tomography, S-wave logging have produced a significant amount of measurable response caused by grouting, but they can inevitably be used only for the qualitative assessment. Thus, this paper deals with an accurate quantitative assessment about the grouting result. In this, a new strategy is introduced, based mainly on evaluating the opening of fractures. For fracture-opening investigation purposes, borehole Televiewer has already proven to be an excellent logging technique that produces both amplitude image and traveltime image. As well known, the traveltime image can be converted to a high precision 3D caliper log with max. 288 arms, which allows to observe the opening of fractures. To evaluate the fracture opening from the traveltime image, an algorithm of practical use was developed, in which image correction due to the borehole deviation, feature discrimination of wall roughness from fractures, automatic evaluation procedure etc. were considered. Field examples are shown to confirm the efficiency of the suggested method.

  • PDF

Objective Image Quality Measurement Model : Focus on Dynamic Range, Noise, Resolution, Color Reproduction, and Preference (객관적인 화질 평가 방법에 관한 연구 : 동적 폭, 노이즈, 해상도, 색재현성, 선호도)

  • Park, Hyung-Ju;Har, Dong-Hwan
    • The Journal of the Korea Contents Association
    • /
    • v.12 no.8
    • /
    • pp.87-95
    • /
    • 2012
  • We propose that a subjective image quality assessment based on objective image quality factors in order to evaluate objectively preference of consumers. In other words, we define objective image quality factors which are easy to accept by manufacturers and they are composed of subjective image quality assessment questionnaires. Also, portrait image is selected by stimulus in order to persue easiness of evaluation for the general subjects. Throughout a subjective image quality assessment model, we evaluate recognition of image quality by consumers and analyze the effectiveness of correlation in terms of the final image quality preference. Analyzing the relationship between image quality factors, we can figure out the preferable image quality and confirm the positive effects on consumers' recognition of image quality. In the results, there are strong relationship between preference and color reproduction, dynamic range, noise, and resolution respectively. especially, the characteristic of portrait, there is high correlation between color reproduction and preference.

An Image Quality Assessment Scheme based on HVS using Gabor Function

  • Eom Minyoung;Choe Yoonsik
    • Proceedings of the IEEK Conference
    • /
    • summer
    • /
    • pp.128-132
    • /
    • 2004
  • In this paper, we propose a new image quality assessment scheme considering the human visual perception characteristics. A subjective quality assessment is obtained by the response of the receptive field in the primary visual cortex and a human's eye can't focus on all of the visual range in a moment. Take advantage of two facts above, we apply Gabor wavelet transform, which is well fit the receptive field in the cortex, to divided constant sized subblocks. Then a local distortion of the subblocks and a global distortion for the entire image are calculated in order. The proposed method has been evaluated using video test sequences provided by the Video Quality Experts Group (VQEG). The experimental results show that good correlation with human perception is obtained using the proposed metric, which is what we called GPSNR.

  • PDF

The Effects of General Country Attributes and General Service Product Attributes on Chinese Consumers' Pre-Assessment and Usage Intention for International Internet Shopping Mall Services According to Their Using Experiences (서비스이용경험에 따른 일반국가속성과 서비스상품속성이 중국소비자의 해외 인터넷쇼핑몰서비스 사전평가와 이용의도에 미치는 영향)

  • Chang, Young-Il;Kim, Kyoung-Hwan;Jung, You-Soo
    • Journal of Information Technology Services
    • /
    • v.11 no.2
    • /
    • pp.49-68
    • /
    • 2012
  • The purpose of this study is to analyse the country image, the pre-assessment, and the usage intention about overseas internet shopping mall service in china and how these factors are related to one another according to internet shopping mall using experience. And this study divided the country image for internet shopping mall service into two components : general country attribute and general service product attribute. In this study it is found that the country image of international internet shopping service is directly related to the pre-assessment, and the pre-assessment is related to usage intention especially in case that chinese consumer has a lot of internet shopping mall using experience. In the other case, the general country attributes affect the general service product attributes but the general service product attributes don't have any relationship with the pre-assessment. For a successful international internet shopping mall service business in China, marketer should recognize that it is important to formulate the policy extending the internet shopping mall experience as well as using the country image.

No-reference Image Blur Assessment Based on Multi-scale Spatial Local Features

  • Sun, Chenchen;Cui, Ziguan;Gan, Zongliang;Liu, Feng
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.14 no.10
    • /
    • pp.4060-4079
    • /
    • 2020
  • Blur is an important type of image distortion. How to evaluate the quality of blurred image accurately and efficiently is a research hotspot in the field of image processing in recent years. Inspired by the multi-scale perceptual characteristics of the human visual system (HVS), this paper presents a no-reference image blur/sharpness assessment method based on multi-scale local features in the spatial domain. First, considering various content has different sensitivity to blur distortion, the image is divided into smooth, edge, and texture regions in blocks. Then, the Gaussian scale space of the image is constructed, and the categorized contrast features between the original image and the Gaussian scale space images are calculated to express the blur degree of different image contents. To simulate the impact of viewing distance on blur distortion, the distribution characteristics of local maximum gradient of multi-resolution images were also calculated in the spatial domain. Finally, the image blur assessment model is obtained by fusing all features and learning the mapping from features to quality scores by support vector regression (SVR). Performance of the proposed method is evaluated on four synthetically blurred databases and one real blurred database. The experimental results demonstrate that our method can produce quality scores more consistent with subjective evaluations than other methods, especially for real burred images.

Assessment of speckle image through particle size and image sharpness

  • Qian, Boxing;Liang, Jin;Gong, Chunyuan
    • Smart Structures and Systems
    • /
    • v.24 no.5
    • /
    • pp.659-668
    • /
    • 2019
  • In digital image correlation, speckle image is closely related to the measurement accuracy. A practical global evaluation criterion for speckle image is presented. Firstly, based on the essential factors of the texture image, both the average particle size and image sharpness are used for the assessment of speckle image. The former is calculated by a simplified auto-covariance function and Gaussian fitting, and the latter by focusing function. Secondly, the computation of the average particle size and image sharpness is verified by numerical simulation. The influence of these two evaluation parameters on mean deviation and standard deviation is discussed. Then, a physical model from speckle projection to image acquisition is established. The two evaluation parameters can be mapped to the physical devices, which demonstrate that the proposed evaluation method is reasonable. Finally, the engineering application of the evaluation method is pointed out.

An Image Cytometric MTT Assay as an Alternative Assessment Method of Nanoparticle Cytotoxicity

  • Lee, Song Hee;Park, Jonghoon;Kwon, Dongwook;Yoon, Tae Hyun
    • Bulletin of the Korean Chemical Society
    • /
    • v.35 no.7
    • /
    • pp.1933-1938
    • /
    • 2014
  • Despite increasing importance of in vitro cell-based assays for the assessment of nanoparticles (NPs) cytotoxicity, their suitability for the assessment of NPs toxicity is still in doubt. Here, limitations of widely used cell viability assay protocol (i.e., MTT asssay) for the cytotoxicity assessment of P25 $TiO_2$ NPs were carefully examined and an alternative toxicity assessment method to overcome these limitations was proposed, where the artifacts caused by extracellularly formed formazan and light scattered by agglomerated NPs were minimized by measuring only the intracellular formazan via image cytometric methods.

Land Cover Classification and Accuracy Assessment Using Aerial Videography and Landsat-TM Satellite Image -A Case Study of Taean Seashore National Park- (항공비디오와 Landsat-TM 자료를 이용한 지피의 분류와 평가 - 태안 해안국립공원을 사례로 -)

  • 서동조;박종화;조용현
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.27 no.4
    • /
    • pp.131-136
    • /
    • 1999
  • Aerial videography techniques have been used to inventory conditions associated with grassland, forests, and agricultural crop production. Most recently, aerial videography has been used to verity satellite image classifications as part of the natural ecosystem survey. The objectives of this study were: (1) to use aerial video images of the study area, one part of Taean Seashore National Park, for the accuracy assessment, and (2) to determine the suitability of aerial videography as an accuracy assessment, of the land cover classification with Landsat-TM data. Video images were collected twice, summer and winter seasons, and divided into two kinds of images, wide angle and narrow angle images. Accuracy assessment methods include the calculation of the error matrix, the overall accuracy and kappa coefficient of agreement. This study indicates that aerial videography is an effective tool for accuracy assessment of the satellite image classifications of which features are relatively large and continuous. And it would be possible to overcome the limits of the present natural ecosystem survey method.

  • PDF