著者

山本 敦 赤尾 佳則 東川 佳靖

出版者

日本法科学技術学会

雑誌

日本法科学技術学会誌 (ISSN:18801323)

巻号頁・発行日

vol.20, no.2, pp.113-123, 2015 (Released:2015-07-17)

参考文献数

23

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When printed materials are used to commit crimes, such as threatening letters, font identification is used to estimate the equipment that was used in their production. To identify the font of printed materials, comparison testing with a print reference sample is required. As retrieving the target print sample from a huge volume of samples requires significant time and effort, a method for automatically searching the font is required. In this paper, we propose a similarity measure using SIFT features, which are invariant local features to the zoom and rotation of the character, and a method of retrieving fonts using the similarity measure. Retrieval experiments were performed using 102 font types with 2,230 types of characters for each. The proposed method is effective for retrieving fonts, even when the character size of the query image and the database is different. Furthermore, we propose a method of retrieving fonts at high speed through dimension reduction using principal component analysis. We show that through the proposed speeding up method, the retrieval time can be reduced to one-quarter of the previous speed without lowering retrieval performance.

著者

鈴木 雄亮 金子 毅

出版者

日本法科学技術学会

雑誌

日本法科学技術学会誌 (ISSN:18801323)

巻号頁・発行日

vol.14, no.2, pp.99-105, 2009 (Released:2009-08-25)

参考文献数

10

被引用文献数

1 1

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In this study, the stability of methamphetamine, bromovalerylurea, acetaminophen and salicylic acid in formalin solution was investigated during 90 days. The stability of these drugs was examined in 4 types of formalin solution (10% and 20% concentration pH adjusted formalin (pH7.4) and each concentration pH unadjusted formalin solution) and at 2 temperature conditions (room temperature and cold storage).   Methamphetamine was very stable at cold storage in each formalin solution. In contrast, more than 80% of methamphetamine was converted into its N-methyl derivative, dimethylamphetamine in pH adjusted formalin at room temperature at 90 days. Bromovalerylurea was stable only when in pH unadjusted formalin at cold storage. Under the other conditions, bromovalerylurea was decomposed and observed a compound assumed to be the bromovalerylurea-formaldehyde reaction product by LC/MS. The concentration of acetaminophen was decreased gradually under all conditions and a compound assumed to be the acetaminophen-formaldehyde reaction product was detected by LC/MS and GC/MS. When salicylic acid was stored under all conditions, concentrations of salicylic acid did not change.   Thus, it appears that the stability of drugs varies individually in the presence of formalin and under different conditions (formalin concentration, pH and storage temperature). So, forensic scientists must note when attempting to determine the drugs in the formalin-fixed biological specimens.

著者

森好 浩行 三好 美紀 日野 大樹 中山 英樹 森川 俊雄 中木 真一 糸原 幸次

出版者

日本法科学技術学会

雑誌

日本法科学技術学会誌 (ISSN:18801323)

巻号頁・発行日

vol.12, no.1, pp.27-34, 2007 (Released:2007-06-27)

参考文献数

17

被引用文献数

8 8 1

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Images of the ear are highly valuable for facial photographic identification because the ear has a lot of morphological features, such as the helix, ear lobe, antihelix, scapha, antitragus, tragus, and so on. However, the morphology of ear components changes so easily depending on the camera angle that it is usually difficult to identify people based on images of their ears from surveillance cameras and mug shots.   In this study, the correlation between the morphology of ear components and camera angles was investigated in order to identify people based on ear images taken from different camera angles. The samples were ear images of 56 persons taken at 27 different camera angles for each person. The morphologies of the ear components were compared among the angles and among the subjects. This revealed the morphological changes in the helix, ear lobe, antihelix, and tragus according to the camera angle.   It was found that the morphology was consistent between ear images taken at different camera angles if the compared images satisfied two conditions: the scapha must be clearly observed, and the external acoustic meatus must not be visible. If these conditions are met, it is possible to identify a person by images of his or her ear regardless of the camera angles.