论闭路电视监控系统信息资料在侦查中的运用

近年来,随着我国经济的飞速发展以及人民群众防范意识的不断提高,闭路电视监控系统越来越普及,并得到了广泛运用。为了使闭路电视监控系统信息资料能够更好地运用到侦查破案中去,文章从闭路电视监控系统信息资料概述、信息资料在侦查破案中的运用、如何提高信息资料的使用效率以及使用中应注意的问题四个方面进行了论述,并提出了运用闭路电视监控系统信息资料的新理念、新方法。     

CCTV监控系统、犯罪预防与虚拟侦查

侦查工作的信息化是虚拟侦查得以展开的必要条件,在信息的采集和使用领域,CCTV监控系统对于虚拟侦查具有不可低估的重要作用。通过制定规范的CCTV监控程序,建立有效的内部和外部监督制约机制,能够确保CCTV监控系统得到合法、有效地运用,并且避免公民的隐私权遭到不应有的侵犯。     

Crime-Reduction Effects of Open-street CCTV: Conditionality Considerations

This study addresses the conditional nature of the effectiveness of open-street CCTV (closed circuit television) by examining the differences in the effects (1) between daytime and nighttime crime, (2) between weekday and weekend crime, (3) across specific-crime offenses, and (4) depending on CCTV site characteristics, including location type (e.g. downtown, business district, school/university, or residential area) and the site’s base rate of crime. This study used HLM (hierarchical linear modeling) with 84 repeated measures across 34 camera locations in Cincinnati, Ohio, while also accounting for overlapping camera areas. Overall, the findings provided minimal evidence of the effectiveness of CCTV in reducing crime, though some types of crime were reduced in residential areas especially, and effectiveness was clearly interdependent with an area’s base rate of crime. Finally, WDQ analyses showed that diffusion of benefits occurred much more often than displacement in cases where there was a crime reduction, post-CCTV.     

The impact of CCTV on fundamental rights and crime prevention strategies: The case of the Catalan Control Commission of Video surveillance Devices

Many authors have written about issues related to privacy, legitimacy and efficiency in relation to CCTV systems in public space as a crime prevention strategy. Some have approached them separately; others have tried to come up with more comprehensive approaches. Few, however, have dealt with how such concerns have been put into practice by those who have to decide on the uptake of CCTV. This article considers some reflections on efficacy, legitimacy and privacy in relation to CCTV, as an introduction to the case of how the members of the Control Commission of Video surveillance Devices in Catalonia took these issues into consideration and interpreted the Law when deciding whether to approve a petition submitted by the City Council to install three cameras in Barcelona’s public space in 2003. It concludes by drawing some conclusions from the process, as a way to highlight the complexity of the policy process around surveillance in open, public spaces.     

The necessity of the implementation of Privacy by Design in sectors where data protection concerns arise

This article examines the extent to which Privacy by Design can safeguard privacy and personal data within a rapidly evolving society. This paper will first briefly explain the theoretical concept and the general principles of Privacy by Design, as laid down in the General Data Protection Regulation. Then, by indicating specific examples of the implementation of the Privacy by Design approach, it will be demonstrated why the implementation of Privacy by Design is a necessity in a number of sectors where specific data protection concerns arise (biometrics, e-health and video-surveillance) and how it can be implemented.     

民族村寨旅游开发的CCTV模式——以西双版纳"中缅第一寨"勐景来为例

民族旅游的开发是近年来旅游学术界和实践中争论较多的问题,主要围绕民族文化的保护与开发而展开。村寨旅游是民族旅游开发中一种主要的形式,本文在比较几种民族村寨开发模式的基础上,以“中缅第一寨”———勐景来的成功开发实践为案例分析,提出一种以保护开发为前提、公司起主导作用、有鲜明特色主题、村民普遍受益的多赢发展模式,即CCTV模式。     

Quantifying and Ranking Quality for Acquired Recordings on Digital Video Recorders

As the closed-circuit television (CCTV) security industry transitioned from analog media to digital video recorders (DVRs) with digital storage, the law enforcement community struggled with the means with which to collect the recordings. New guidelines needed to be established to determine the collection method which would be efficient as well as provide the best quality evidence from live DVRs. A test design was developed to measure, quantify, and rank the quality of acquisition methods used on live systems from DVRs typically used in digital CCTV systems. The purpose was to determine guidelines for acquiring the best quality video for investigative purposes. A test pattern which provided multiple quantifiable metrics for comparison between the methods of acquisition was used. The methods of acquisition included direct data download of the proprietary file and open file format as well as recording the video playback from the DVR via the available display monitor connections including the composite video, Video Graphics Array (VGA), and high-definition multimedia interface (HDMI). While some acquisition methods may provide the best quality evidence, other methods of acquisition are not to be discounted depending on the situation and need for efficiency. As an investigator that needs to retrieve video evidence from live digital CCTV systems, the proprietary file format, overall, provides the best quality evidence. However, depending on the circumstance and as recording technology continues to evolve, options other than the proprietary file format may provide quality that is equal to or greater than the proprietary file format.     

Efficient height measurement method of surveillance camera image

As surveillance cameras are increasingly installed, their films are often submitted as evidence of crime, but very scant detailed information such as features and clothes is obtained due to the limited camera performance. Height, however, is relatively not significantly influenced by the camera performance. This paper studied the height measurement method using images from a CCTV. The information on the height was obtained via photogrammetry, including the reference points in the photographed area and the calculation of the relationship between a 3D space and a 2D image through linear and nonlinear calibration. Using this correlation, this paper suggested the height measurement method, which projects a 3D virtual ruler onto the image. This method has been proven to offer more stable values within the range of data convergence than those of other existing methods.     

Comparison of the Performance of Two Methods for Height Estimation

Abstract: In the case study, two methods of performing body height measurements in images are compared based on projective geometry and 3D modeling of the crime scene. Accuracy and stability of height estimations are tested using reconstruction images of test persons of known height. Given unchanged camera settings, predictions of both methods are accurate. However, as the camera had been moved in the case, new vanishing points and camera matches had to be created for the reconstruction images. 3D modeling still yielded accurate and stable estimations. Projective geometry produced incorrect predictions for test persons and unstable intervals for questioned persons. The latter is probably caused by the straight lines in the field of view being hard to discern. With the quality of material presented, which is representative for our case practice, using vanishing points may thus yield unstable results. The results underline the importance of performing validation experiments in casework.     

Measurement Uncertainty When Estimating the Velocity of an Allegedly Speeding Vehicle from Images

Abstract: Sometimes the question arises whether it is possible to estimate the velocity of a speeding car recorded by closed circuit television cameras. By estimating the travelled distance of the car between two images and the time elapsed, estimation of the velocity is rather straightforward. However, to quantify the corresponding measurement uncertainty, the data analysis becomes more involved. The article describes two approaches as to how to derive the measurement uncertainty. In the first method, distance and timing are estimated separately, and the two uncertainties are combined to derive the measurement uncertainty for the velocity. For this, a frequentist and a Bayesian approach are described. In the second method, the measurement uncertainty for the speed is derived directly using validation recordings of a car driving by at known speed. The choice which method to use depends mainly on the length of the path that the car has travelled.