中口 俊哉

The fuzzy commitment scheme (FCS) is one of the most effective biometric cryptosystems (BCs) that provide secure management of cryptographic keys using biometric templates. In this scheme, error correcting codes (ECCs) are firstly employed to encode a cryptographic key into a codeword which is then secured via linking (committing) it with a biometric template of the same length. Unfortunately, the key length is constrained by the size of the adopted biometric template as well as the employed ECC(s). In this paper, we propose a secure iris template protection scheme that combines cancelable biometrics with the FCS in order to secure long cryptographic keys without sacrificing the recognition accuracy. First, we utilize cancelable biometrics to derive revocable templates of large sizes from the most reliable bits in iris codes. Then, the FCS is applied to the obtained cancelable iris templates to secure cryptographic keys of the desired length. The revocability of cryptographic keys as well as true iris templates is guaranteed due to the hybridization of both techniques. Experimental results show that the proposed hybrid system can achieve high recognition accuracy regardless of the key size.

<p>This paper aims to perform projector-based shape measurement and augmented reality (AR) in parallel for surgical navigation. Hence, it proposes a shape measurement method which projects AR image and structured light at the same time by embedding structured light into AR image. We evaluated the measurement error by changing the shape of the target object and amplitude. Besides, we evaluated the perception threshold of the embedded pattern by changing frequency and amplitude.</p>

Partial intestinal obstruction causes smooth muscle hypertrophy, enteric neuronal plasticity, motility disorders, and biomechanical remodeling. In this study we characterized the stimulus-response function of afferent fibers innervating the partially obstructed jejunum. A key question is whether changes in afferent firing arise from remodeled mechanical tissue properties or from adaptive afferent processes. Partial obstruction was created by placing a polyethylene ring for 2 wk in jejunum of seven rats. Sham obstruction was made in six rats and seven rats served as normal controls. Firing from mesenteric afferent nerve bundles was recorded during mechanical ramp, relaxation, and creep tests. Stress-strain, spike rate increase ratio (SRIR), and firing rate in single units were assessed for evaluation of interdependency of the mechanical stimulations, histomorphometry data, and afferent nerve discharge. Partial intestinal obstruction resulted in hypertrophy and jejunal stiffening proximal to the obstruction site. Low SRIR at low strains during fast distension and at high stresses during slow distension was found in the obstructed rats. Single unit analysis showed increased proportion of mechanosensitive units but absent high-threshold (HT) units during slow stimulation, decreased number of HT units during fast stimulation, and shift from HT sensitivity towards low threshold sensitivity in the obstructed jejunum. Biomechanical remodeling and altered afferent response to mechanical stimulations were found in the obstructed jejunum. Afferents from obstructed jejunum preserved their function in encoding ongoing mechanical stimulation but showed changes in their responsiveness. The findings support that mechanical factors rather than adaption are important for afferent remodeling.

Background: The relation between tongue color and gastroesophageal disease is unclear. This study was done to investigate the associations between tongue color (TC), endoscopic findings, Helicobacter. pylori infection status, and serological atrophic gastritis (SAG). Methods: The participants were 896 residents of Ishigaki Island, Okinawa, aged 28-86 years. The tongue was photographed, esophagogastroduodenoscopy was done, and serum antibody to H. pylori was measured. SAG was defined as a serum Pepsinogen (PG)Ilevel <= 70 ng/ml and a PGI/IIratio <= 3.0. TC was measured by the device-independent international commission on Illumination 1976 L*a*b* color space standards at four points: (1) edge, (2) posterior, (3) middle, and (4) apex. We also calculated the ratio of the tongue edge to the three other measured points to examine the association between the coating of the tongue and the endoscopic and laboratory findings. Results: Participants were excluded who had two or more endoscopic findings (n = 315) or who had SAG without seropositivity to H. pylori (n = 33). The remaining 548 participants were divided into three groups: SAG and seropositive to H. pylori (n = 67), seropositive to H. pylori alone (n = 56), and without SAG and seronegative for H. pylori (n = 425). We divided 425 residents into a single endoscopic finding positive group (n = 207) and a negative group, which served as a control (n = 218). The most frequent single endoscopic finding was esophageal hernia (n = 110), followed by erosive esophagitis (n = 35) and erosive gastritis (EG) (n = 45). EH was significantly associated with TC (2b*/1b*) (P < 0.05). EG was significantly associated with TC (3a*, 3b*) (P < 0.05). Seropositivity to H. pylori was significantly associated with TC (3 L*, 3 L*/1 L*) (P < 0.05, < 0.01), and seropositivity to both H. pylori and SAG was significantly associated with TC (3 L*/1 L*) (P < 0.05). Multivariate analysis extracted TC (3a*, 3b*) as an independent factor associated with a differential diagnosis of EG (Odds ratio (OR) 2.66 P = 0.008, OR 2.17 P = 0.045). Conclusions: The tongue body color of the middle area reflects acute change of gastric mucosa, such as erosive gastritis. Tongue diagnosis would be a useful, non-invasive screening tool for EG.

Tongue diagnosis is a noninvasive diagnosis and is traditionally one of the most important tools for physicians who practice Kampo (traditional Japanese) medicine. However, it is a subjective process, and its results can depend on the experience of the physician performing it. Previous studies have reported how to measure and evaluate the shape and color of the tongue objectively. Therefore, this study focused on the glossy component in order to quantify tongue moisture in tongue diagnosis. We hypothesized that moisture appears as a gloss in captured images and measured the amount of water on the tongue surface in 13 subjects. The results showed a high correlation between the degree of gloss and the amount of water on the tongue surface and suggested that the moisture on the tongue can be estimated by the degree of gloss in a captured image. Because the moisture level on the tongue changes during the course of taking photos, it became clear that we had to wait at least 3 minutes between photos. Based on these results, we established the tongue image analyzing system (TIAS), which can consistently record the gloss and color of the tongue surface simultaneously.

Osteoarthritis of the knee joint (KOA) is an important problem to be solved in aged society. Objective assessment of disease progression is mandatory for establishing adequate treatment system. Radiographic examination is a standard method but it is too rough to detect subtle changes occur in limited period. Contrary to this, magnetic resonance imaging (MRI) is expected to work as biomarker as it appears to be keen enough to capture subtle changes. Several MRI-based assessment systems have been developed to assess the status of KOA but they are too complicated and time consuming. Originally developed system, the Irregularity Index System (I-I System) is one of those but the simplest method because it is composed of only one item; i.e., the contour of the femoral condyle. Cross-sectional study revealed good correlation between irregularity of the contour and clinical severity but longitudinal changes are yet to be solved. In this paper longitudinal change of irregularity was determined using publicly available MRI data base concerning KOA. As a result, I-I System could detect changes over average of 14 months and it related to deterioration of clinical knee score.

In traditional Japanese medicine (Kampo medicine), tongue color is important in discerning a patient's constitution and medical conditions. However, tongue color diagnosis is susceptible to the subjective factors of the observer. To investigate factors involved in tongue color diagnosis, both color discrimination and tongue color diagnosis were researched in 68 Kampo medical practitioners. Color discrimination was studied by the Farnsworth-Munsell 100 Hue test, and tongue color diagnosis was studied by 84 tongue images. We found that overall color discrimination worsened with aging. However, the color discrimination related to tongue color regions was maintained in subjects with 10 or more years of Kampo experience. On the other hand, tongue color diagnosis significantly differed between subjects with <10 years of experience and >= 10 years of experience. Practitioners with >= 10 years of experience could maintain a consistent diagnosis of tongue color regardless of their age.

漢方医学では舌の色や形状を観察する舌診が患者の体質や病状を知る重要な手掛かりになると考えている。我が国において，舌診に関する書籍が複数発行されているが，記載内容が不統一で臨床的な舌診所見の標準的な記載方法はまだ確立してない。舌診の研究および学生への漢方教育において標準的な舌診臨床所見は必要である。そこで舌診の日本の文献（計12文献）を用いて，色調や形態の記載について比較検討した。その結果を用いて舌診に習熟した多施設の漢方専門医のコンセンサスを得た上で，舌診臨床診断記載の作成に至った。作成にあたり，実際臨床において短時間で観察し得る舌所見を捉える事と初学者でも理解し易いよう，微細な所見の違いよりも確実に捉えやすい舌診所見に重点を置いた所見記載とした。

Since metabolic syndrome is a cause of lifestyle-related diseases, and its early diagnosis and an evaluation of visceral fat are important, this study proposes a new method of estimating the amount of fat. The goal of this study is to estimate visceral fat from estimation of subcutaneous fat and total fat. The subcutaneous fat is estimated from the elasticity of the lumbar area, and the total fat is estimated from body information such as the abdominal vertical and lateral width, and body weight. Finally, the estimated subcutaneous fat is subtracted from the estimated total fat to calculate the visceral fat. Measurement tests conducted to verify the constructed visceral fat estimation model showed good results, with a correlation of 0.96 between the visceral fat area estimated by the proposed method and the actual measured area. The reproducibility of the estimation model was also verified by the cross validation method. © 2013 ISAROB.

In this paper, we propose using earth mover's distance (EMD) to obtain the appropriate similarity between each histogram for segmentation of abnormal liver regions with mapping of the distances by multidimensional scaling. Conventionally, the similarity between each histogram is calculated by integrating the difference between each bin of the histograms. However, this similarity is unsuitable for appropriate comparison of the histograms because the number of bins for calculating the local histograms of computed tomography images varies. We used EMD to resolve this problem regarding the difference in bin numbers, and the obtained distances are used for mapping the local histograms by multidimensional scaling to low-dimensional space. In the low-dimensional space, the abnormal liver region was well segmented by support vector machine in the test datasets. © 2013 ISAROB.

This paper aims to develop a virtual auscultation training system by employing simulated patient. Currently in order to train and examine auscultation skills, mannequin-based training system is used widely. It has, however, several problems such as lack of nervousness, high cost and not smooth procedure in examination. To overcome these problems, the virtual auscultation simulator is proposed, which is composed of a virtual stethoscope, a position tracker and a processor. To investigate the efficacy, subjective evaluation experiment was performed. From the result, the proposed system is significantly superior for reproducing the sense of nervousness to the mannequin-type simulator, and its efficacy was shown totally. © 2013 American Scientific Publishers.

In this paper, the relative influences of misalignment such as cross-talk, vertical shift, and motion blur on visual fatigue by using a binocular stereoscopic display has been verified. Experiments were conducted for two cases: a still image and a motion image. They were evaluated by using the simulator sickness questionnaire (SSQ). By changing the disparity angle, cross-talk, and vertical shift in the still-image experiment, it was found that the SSQ score of each parameter increased as the amount of each factor increased. With a two-sample t-test between the presence and absence of each factor, a significant difference was found for the case of a more than 36-arcmin disparity, more than 20% cross-talk, and more than 10% vertical shift. In the motion-image experiment, in which motion speed and the misalignment were varied, it was found that movement of the disparity angle caused much more visual fatigue in comparison with the misalignment factors, which were cross-talk and vertical shift. In contrast, motion images in addition to the cross-talk and/or vertical shift had a slight but unnoticeable relationship to an increase in visual fatigue. Therefore, it was concluded that vertical shift dominated the evaluation for still images, and the movement itself dominated the evaluation for motion images. The results suggest that it is necessary to evaluate visual fatigue according to the representing case, still or motion images, of a 3-D stereoscopic display.

We propose a VR-based injection training system using Simulated Patient (SP) with an original haptic needle which can represent a haptic expression. SP is trained to realistically portray a real patient. In order to increase a realistic sensation and effect of training, it is important to train with real human. Therefore we propose a new training system which fuse SP and virtual training system. In the proposed system, trainee can virtually puncture the SP using the haptic needle. In addition, the haptic needle can represent a haptic expression of needle insertion of the virtual anatomical model. We developed the haptic needle which can represent a reaction force of puncturing. A reaction force of needle insertion is generated by clipping needle by using computer-controlled electromagnet and permanent magnet, and then a friction force is accrued. By using the proposed system, trainee can feel virtual puncture as well as operating for real patient.

高ダイナミックレンジ（High Dynamic Range, HDR）画像は，通常の画像よりもはるかに広い輝度範囲を記録した画像で，通常の画像よりも高精細な画像処理が可能であり，デジタル画像処理の中間処理やコンピュータグラフィックスで広く用いられるようになった．しかし，一般的に使用されているディスプレイの再現階調は狭く，HDR画像を直接表示することはできない．HDR画像を通常のディスプレイに表示するには，階調を圧縮するトーンマッピングと呼ばれる処理が必要である．これに対して，我々は観察者の注視情報に応じて画像の見えを明瞭にするトーンマッピング手法を提案してきた．さらに，画素値の高い領域注視時のパラメータ推定を改善した．しかし，これらの手法は従来の手法との比較評価が行われていない．そこで，本論文では，注視情報を用いたトーンマッピング手法の有効性を検証するため，画像の好ましさの観点から，注視情報を用いたトーンマッピング手法と従来手法の比較実験を行った．<br>

従来のICG観察システムでは，蛍光をモニタで観察するため，蛍光部位と観察部位の位置関係把握が困難であり，またシステムが高価であることから広く普及するに至らなかった．そこで本研究では，市販のUSBカメラとレーザープロジェクタを用いて蛍光を取得，投影し，より低価格で直感的な観察システムを構築する．本システムは乳がんのセンチネルリンパ節同定，皮膚がん，リンパ浮腫など，体表の比較的浅い部分の病変部を主な観察対象とする．本システムでは赤外LEDを用いてICGを励起させ，励起画像と非励起画像の差分をとることで蛍光部位を抽出する．取得画像は空間コード化法を用いて歪み補正を行い，レーザープロジェクタで対象部位に投影する．投影距離200mmにおける平均投影誤差は0.5mm以内であった．ファントム実験の結果，最大深さ12mmのICG蛍光を観察可能であった．また動物実験によって，本システムの臨床における実現可能性が示唆された．

Proving the security of cancelable biometrics and other template protection techniques is a key prerequisite for the widespread deployment of biometric technologies. BioEncoding is a cancelable biometrics scheme that has been proposed recently to protect biometric templates represented as binary strings like iris codes. Unlike other template protection schemes, BioEncoding does not require user-specific keys or tokens. Moreover, it satisfies the requirements of untraceable biometrics without sacrificing the matching accuracy. However, the security of BioEncoding against smart attacks, such as correlation and optimization-based attacks, has to be proved before recommending it for practical deployment. In this paper, the security of BioEncopding, in terms of both non-invertibility and privacy protection, is analyzed. First, resistance of protected templates generated using BioEncoding against brute-force search attacks is revisited rigorously. Then, vulnerabilities of BioEncoding with respect to correlation attacks and optimization based attacks are identified and explained. Furthermore, an important modification to the BioEncoding algorithm is proposed to enhance its security against correlation attacks. The effect of integrating this modification into BioEncoding is validated and its impact on the matching accuracy is investigated empirically using CASIA-IrisV3-Interval dataset. Experimental results confirm the efficacy of the proposed modification and show that it has no negative impact on the matching accuracy.

Purpose Kampo medicine (Japanese traditional herbal medicine) contains concepts useful for preventive medicine. For example, "Mibyou" (disease-oriented state) aims to prevent illness by early recognition. Kampo diagnosis is based on subjective examinations, such as tongue inspection, by trained specialist physicians. An objective metric of the tongue color spectrum was developed as a surrogate for subjective visual inspection. Methods Tongue images were acquired with a hyperspectral imaging system, and the uncoated tongue region was segmented automatically. The spectral information of the uncoated tongue area was analyzed by principal component analysis (PCA). The component vector most representative of each clinical symptom was found by rotating the vector on a plane spanned by two arbitrary principal component vectors. Results The system was tested in human volunteers. Forty-four hyperspectral images were acquired from 30 healthy male subjects for initial testing. The Oketsu (blood stagnation) score was determined by an experienced clinician in Kampo medicine from 27 of 30 subjects. The correlation between respective principal components and Oketsu score was 0.67 at maximum, and increased to 0.73 by linear combination, while it was -0.75 by vector rotation. Significant correlations for many disorders were demonstrated, and vector rotation showed better correlation than linear combination. Conclusions A PCA-based algorithm was developed to objectively evaluate patients using color images of the tongue surface. Testing showed that this method was a feasible surrogate for expert visual tongue analysis. This tool should help non-trained people identify "Mibyou" health status for individuals. The algorithm is free of empirical criteria, and it may be it applicable to many hyperspectral image types.