An innovative method for human height estimation combining video images and 3D laser scanning

Digitalization has increased the number of video surveillance systems that sometimes capture crime images. Traditional methods of human height estimation use projective geometry. However, sometimes they cannot be used because the video camera surveillance system is not available or has been moved and there are no reference lines on the frame. Scientific studies have developed a new method for human height estimation using 3D laser scanning. This model necessarily requires a series of approximations, which increase the final measurement error. To overcome this problem, in the present study, images of a subject are projected directly on the 3D model, estimating the height of the subject. This article describes the methodological approach adopted through the analysis of a real case study in a controlled environment executed by Carabinieri Forensic Investigation Department (Italy). The aim is to obtain a human anthropometric measure derived from frames extracted from the videos associated with the digital survey of the framed area obtained with 3D laser scanning and point cloud analysis. The result is the height estimation of five subjects filmed by a camera obtained through the combination of 2D images extracted by a DVR/surveillance systems with 3D laser scanning. Results show that most estimated measurements are less than the real measurement of the subject; it also depends on the posture of the subject while walking. Furthermore, results shows the differences between the real height and the estimated height with a statistical approach.     

Single‐Image Rectification Technique in Forensic Science

Many researchers have been working in Spain to document the communal graves of those assassinated during the Spanish Civil War. This article shows the results obtained with two low‐cost photogrammetric techniques for the basic documentation of forensic studies. These low‐cost techniques are based on single‐image rectification and the correction of the original photo displacement due to the projection and perspective distortions introduced by the lens of the camera. The capability of image rectification is tested in an excavation in the village of Loma de Montija (Burgos, Spain). The results of both techniques are compared with the more accurate data obtained from a laser scanner system RIEGL LMS‐Z390i to evaluate the error in the lengths. The first technique uses a camera situated on a triangle‐shaped pole at a height of 5 m and the second positions the camera over the grave using a linearly actuated device. The first technique shows measurement errors less than 6%, whereas the second shows greater errors (between 8% and 14%) owing to the positioning of the carbon‐fiber cross on an uneven surface.     

Tattoos and Human Identification: Investigation into the Use of X‐Ray and Infrared Radiation in the Visualization of Tattoos

Any person with a tattoo known to their family or friends could potentially be identified from the presence of such personal identifying markers. Problems in identification utilizing tattoos may arise when these markers are removed or defaced in some way. This paper uses infrared wavelengths at 760, 850, and 950 nm to improve the visualization of laser‐removed or covered up tattoos and also to establish whether the ink pigments used can be observed on radiographs from any metal that may be present. The results obtained indicate that some older inks have a high enough metallic content to allow them to be viewed on a radiograph, while infrared light can demonstrate latent ink still present in the skin after laser removal and can also be utilized to distinguish an original tattoo through a secondary “cover‐up” tattoo. Infrared photography and radiography have been shown to improve tattoo visualization in a forensic context.     

Fluorescence spectra and images of latent fingerprints excited with a tunable laser in the ultraviolet region

Fluorescence spectra of sebum-rich latent fingerprints were studied with a tunable laser for non-destructive fingerprint detection without chemical treatment. The tunable laser consists of a nanosecond pulsed Nd-YAG laser and an optical parametric oscillator (OPO) crystal. The fluorescence spectra and images were measured at various excitation wavelengths in the ultraviolet region by the time-resolved fluorescence method. We have previously reported that a typical fluorescence spectrum of fingerprints consists of two peaks located at c. 330 and 440 nm. In order to determine the wavelength of optimal excitation, excitation spectra were measured at wavelengths ranging from 220 to 310 nm. The fluorescence intensity of the 330 nm peak became maximal with excitation at 280 nm. The images of latent fingerprints on white papers were also measured and the clearest image was obtained with excitation at 280 nm. The influence of continuous irradiation on the fluorescence of fingerprints was measured at the optimal excitation wavelengths. The 330 nm peak was strong at first and decreased with continuous irradiation, whereas the 440 nm peak, which was weak at first, increased gradually.     

论村民自治中罢免程序的规范问题

《村委会组织法》规定了村民享有罢免权,但是该法对于村民行使罢免权的具程序规定较为粗疏和抽象,造成了村民在现实中行使罢免权时受到重重阻力。完善罢免程序宜降低罢免决议通过的门槛,简化罢免理由;构建罢免程序中的回避制度,确保程序公正;明确罢免程序的具体步骤和时间限制;建立健全对于阻挠罢免权行使的行为的惩罚机制,将对村民行使罢免权的保护落到实处。     

紫外激光技术显现潜在指印的研究

目的研究显现潜在指印的新技术。方法用自主研发的266nm短波紫外线输出的ND：YAG激光器作为激发光源激发渗透性客体表面的潜在指印,使指印发出荧光。结果能有效显现出亮纹线暗背景的潜在指印发光图像。结论利用该紫外激光技术可以显现纸张等渗透性客体表面的潜在指印。     

激光雕刻法伪造印章印文的检验技巧

激光雕刻技术是当代激光技术、电脑技术、精密数控技术、电子技术等的结合,是光、机、电一体化的一种刻印技术,大大提高了印章刻制的丁艺水平和制作速度,已被社会广泛应用.同时,用激光雕刻法伪造印章印文的案件也不断出现,且达到真假难辨的程度,对此类案件的鉴定是文检人员面临的一个难题,需要不断地总结和更新检验方法.     

Stability and Specificity of Counterfeit Protection System Code

In this study, the stability and specificity of a counterfeit protection system (CPS) code were determined. This research involved an analysis of a counterfeit protection system code unit over time using the pattern location measurement method. We collected 379 sample sheets from 196 printers or photocopiers, covering 14 original brands, including 129 models. There was an interval of at least two months between the collections of samples from each machine. Four types of characteristics were established: CPS pattern unit, distance of the CPS unit, position of dots, size and shape of the dot. Except for the partial changes in the Xerox brand, no other brand exhibited changes over time. This implies that the CPS characteristics are stable. Meanwhile, no correlation was noted between the combinations of the characteristic systems in the collected samples, which implied strong specificity.     

Determination of the Sequence of Intersecting Lines Between Toners and Seals by Laser Fluorescence Microscope

Fluorescence microscope is considered to be one of the most effective ways to examine the sequence of intersecting seal and toner lines of questioned documents. In reality, however, the toner (mainly divided into compact and noncompact toners) and seal of a questioned document have such a complex morphology and sequence of crossing lines that current methods cannot meet the requirement of practical document identification. In view of the challenges of document examination, a laser fluorescence microscope and method are developed in this study. The developed microscope provides additional functionality to traditional fluorescence microscopes of transmitted light modality, laser excitation, selectable excitation wavelength, and selectable fluorescence filters. The results obtained from the method of comparisons between transmitted light and fluorescence modalities were positive under most conditions, particularly for noncompact toner examination for which a 100% accuracy rate and 90% detection rate were achieved in blind testing.     

Application of 3D Laser Scanner to Forensic Engineering

In the case of building collapses and overturned structures, a three‐dimensional (3D) collapse or overturn model is required to reconstruct the accident. As construction sites become increasingly complex and large, 3D laser scanning is sometimes the best tool to accurately document and store the site conditions. This case report presents one case of a structure collapse and one case of an overturned crane reconstructed by a 3D laser scanner. In the case of structural collapse of a prefabricated shoring system, a 3D model reconstructed all the members successfully, a task that is nearly impossible using a scale such as a tape measure. The reconstructed prefabricated shoring system was verified through a structural analysis through comparison with the construction drawings to investigate faults in construction. In the case of the overturned crane, the jib angle and other major dimensions were successfully acquired through 3D laser scanning and used to estimate the working radius. As a result, the propriety of the working radius with the given lifting load was successfully determined.