• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권11호
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• pp.4043-4064
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• 2021

Night-time image quality evaluation is an urgent requirement in visual inspection. The lighting environment of night-time results in low brightness, low contrast, loss of detailed information, and colour dissonance of image, which remains a daunting task of delicately evaluating the image quality at night. A new blind quality assessment metric is presented for realistic night-time scenario through a comprehensive consideration of contrast, texture, and colour in this article. To be specific, image blocks' color-gray-difference (CGD) histogram that represents contrast features is computed at first. Next, texture features that are measured by the mean subtracted contrast normalized (MSCN)-weighted local binary pattern (LBP) histogram are calculated. Then statistical features in Lαβ colour space are detected. Finally, the quality prediction model is conducted by the support vector regression (SVR) based on extracted contrast, texture, and colour features. Experiments conducted on NNID, CCRIQ, LIVE-CH, and CID2013 databases indicate that the proposed metric is superior to the compared BIQA metrics.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.281-282
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• 1998

Recently, there has been growing interest in the assessment of physiological parameters on brain perfusion that provide more information than pure morphologic diagnosis. Quantification of parameters that characterize cerebral micro-circulation with magnetic resonance imaging is of great relevance for clinical application. We determine the local tissue concentration by exponential relationship between the relative signal reduction S(t)/$S_0$ and local tissue concentration of contrast material $C_m(t)$ in dynamic susceptibility contrast enhanced MR imaging. And then we made relative regional blood volume map by calculating the area under the measured concentration-time curves $C_m(t)$ during first pass of paramagnetic contrast material as a preliminary step for perfusion map. These images make it possible to compare the rCBV in different brain regions in one individual at a time. We have it in contemplation to obtain arterial and brain signal time curves simultaneously to make absolute rCBV and perfusion (rCBF) map. These maps may provide the method of comparative investigations of different patients having strong variation in AIF.

• Journal of Veterinary Science
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• 제22권2호
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• pp.22.1-22.9
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• 2021

Background: Standing surgery in horses combining intravenous sedatives, analgesics and local anaesthesia is becoming more popular. Ultrasound guided (USG) peribulbar nerve block (PB) has been described in dogs and humans for facial and ocular surgery, reducing the risk of complications versus retrobulbar nerve block (RB). Objective: To describe a technique for USG PB in horse cadavers. Methods: Landmarks and PB technique were described in two equine cadaver heads (Phase 1), with computed tomography (CT) imaging confirming contrast location and spread. In Phase 2, ten equine cadaver heads were randomised to two operators naive to the USG PB, with moderate experience with ultrasonography and conventional "blind" RB. Both techniques were demonstrated once. Subsequently, operators performed five USG PB and five RB each, unassisted. Contrast location and spread were evaluated by CT. Injection site success was defined for USG PB as extraconal contrast, and for RB intraconal contrast. Results: Success was 10/10 for USG PB and 0/10 for RB (p < 0.001). Of the RB injections, eight resulted in extraconal contrast and two in the masseter muscle (p = 0.47). Conclusions: The USG PB had a high injection site success rate compared with the RB technique; however, we cannot comment on clinical effect. The USG technique was easily learnt, and no potential complications were seen. The USG PB nerve block could have a wide application for use in horses for ocular surgeries (enucleations, eyelid, corneal, cataract surgeries, and ocular analgesia) due to reduced risk of iatrogenic damage. Further clinical studies are needed.

• 약학회지
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• 제53권6호
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• pp.328-333
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• 2009

Contrast media are substances that are used to enhance the contrast of structures or fluids within the body in medical imaging. Those are commonly used to enhance the visibility of blood vessels and the gastrointestinal tract. The aim of this study is to evaluate patients who got injected iopamidol, developed as one of contrast medium regarding changes in cardiovascular system and especially, adverse drug reactions. This study were performed on randomly selected a total of 51 patients (range of 15~85 years old) who got injected contrast medium, Iopamidol at a P hospital in Gyeonggi province from September 22nd, 2008 to January 24th, 2009. Data were collected by questionnaire though person to person. We analyzed the data by SPSS (Version 12. for windows). Methods of analysis were frequency and cross analysis. In results, 19.6% (n=10) were founded for adverse drug reactions of contrast medium. 25.0% (n=4) of 10 patients who had adverse drug reactions of contrast medium had took abdomen contrast test. 2 patients of those took contrast test for chest. Also, 3.9% (n=2) patients felt vomiting and nausea after injection of contrast medium. In conclusion, 19.6% patients experienced adverse drug reaction of contrast medium. Therefore, when taking radiation test, we should make efforts to minimize adverse drug reactions to achieve suitable and effective treatment.

• Journal of the Korean Data and Information Science Society
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• 제19권2호
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• pp.475-485
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• 2008

One of main issues in watermarking is to resolve the strength of watermark for solving the problem of trade-off between fidelity and robustness of watermarking. In the previous research, the strength of watermark has been resolved fixed value generally without considering local image characteristics such as image brightness, contrast, and edge. This paper proposes a new model to predict the strength of watermark considering local image characteristics such as image brightness, contrast, and edge for digital wavelet transform(DWT)-based image watermarking. For the study, psychological experiment was fulfilled to measure the human image perception and regression analysis showed the proposed model was statistically significant at the level of ${\alpha}\;=\;0.01$. Also the model is practically validated on fidelity and robustness of watermarking.

• 대한의용생체공학회:의공학회지
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• 제18권2호
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• pp.113-120
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• 1997

This paper presents an optimal design for the SPECT reconstruction filter, based on a physical limit of SPECT lesion detection capability. To increase the performance of the filter on lesion detectability, the filter design was focused on increasing the local SyW ratio of a threshold lesion, that was determined by minimum detectable lesion size (MDU) from SPECT lesion detectabllity contrast-detail curve. The proposed filter showed flexible window characteristics of resolution recovery and noise smoothing for MDLSs in the resolution-limited and photon-limited regions, respectively, compennting for the relative impact of the main limitation factors on threshold detectability. The simulated results showed good adaptability of the proposed filter to the changes in physical parameters of photon counts, object contrast, and detector system resolution.

• The Korean Journal of Pain
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• 제29권4호
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• pp.255-261
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• 2016

Background: Thoracic epidural anesthesia is frequently used to maintain intraoperative and postoperative analgesia. Frequently, 3 ml of local anesthetic is used as a test dose, or for intermittent epidural injection. We assessed the extent of the spread of 3 ml of contrast medium in the thoracic epidural space and attempted to identify any correlating factors affecting the epidurography. Methods: A total of 70 patients were enrolled in the study, and thoracic epidural catheterizations were performed under fluoroscopic guidance. Using 3 ml of contrast medium, epidurography was evaluated to confirm the number of spinal segments covered by the contrast medium. Correlation analysis was performed between patient characteristics (sex, age, body mass index, weight, height, and location of catheter tip) and the extent of the contrast spread. Results: The mean number of vertebral segments evaluated by contrast medium was $7.9{\pm}2.2$ using 3 ml of contrast medium. The contrast spread in the cranial direction showed more extensive distribution than that in the caudal direction, with statistical significance (P < 0.01). Patient height demonstrated a negative correlation with the extent of distribution of contrast medium (r = -0.311, P < 0.05). Conclusions: Thoracic epidurography using 3 ml of contrast medium results in coverage of a mean of $7.9{\pm}2.2$ spinal segments, with more extensive cranial spread, and patient height showed a weak negative correlation with the distribution of contrast medium.

• IEIE Transactions on Smart Processing and Computing
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• 제5권1호
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• pp.49-54
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• 2016

Regarding global and local factors of a set of features, a given single image or multiple images is a common approach in image processing. This paper introduces an application of an adaptive version of non-local filter whose original version searches non-local similarity for removing noise. Since most images involve texture partner in both foreground and background, extraction of signified regions with texture is a challenging task. Aiming to the detection of visual attention regions for images with texture, we present the contrast analysis of image patches located in a whole image but not nearby with assistance of the adaptive filter for estimation of non-local divergence. The method allows extraction of signified regions with texture of images of wild life. Experimental results for a benchmark demonstrate the ability of the proposed method to deal with the mentioned challenge.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1156-1159
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• 2008

Local dimming driving has advantages in reducing power consumption and improving contrast ratio(CR). In an LED backlight unit(BLU), many small LED blocks are implemented in 2-dimmensional space, and luminance of the blocks is controlled by a local dimming algorithm. However, such a BLU can induce various recognizable artifacts. A new novel algorithm is proposed for exact block luminance calculation to correct local dimming artifacts. Also we discuss modified low-gray-level dimming to achieve much aggressive power saving in a local dimming BLU system.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(4)
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• pp.251-254
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• 2002

Currently many devices reproduce electronic images in a variety of ways. However, the colors that are reproduced are different from the original color due to the differences in the gamut between devices. In this paper, a gamut mapping method utilizing a simultaneous mapping function and a lightness rescaling is proposed. This method enhance the local-color characteristics and lightness contrast. The experimental result shows that the overall contrast and the colorfulness were increased.