基于亮度感知权重的夜间图像去雾技术

目的对夜间雾天环境下成像设备获取的图像进行去雾和图像增强处理,以便给公安机关的图像侦查工作提供直观的侦查信息。方法首先基于夜间大气散射物理模型,采用通道差引导的低通滤波器估计环境照度;其次使用亮通道和暗通道先验分别估算图像中光源区和非光源区的环境透射率,然后采用一种亮度感知权重的方式将二者融合得出最终的混合环境透射率;最后对夜间大气模型公式进行求解获得去雾图像。在此基础上使用CLAHE和SoG算法对图像视觉效果进行增强。结果经过对大量实际案例和计算机合成的夜间雾天图像进行处理,实验结果表明本文采用的去雾与图像增强技术在客观评价方面:偏色检测因子降低65%、平均梯度提高233%、信息熵提高7%,相较于其他主流方法均占显著优势;在主观评价方面:本文方法能同时提升图像颜色动态范围、矫正图像偏色、增强图像暗部细节。结论基于亮度感知权重的夜间去雾与图像增强技术能够有效增强夜间雾天图像的暗部细节、提高图像对比度和解决图像偏色问题,能为公安机关的图像侦查工作提供更直观有效的信息。     

一起非正常死亡案件中行车记录仪视频检验及启示

随着行车记录仪功能的不断丰富及智能化程度的提升,其工作模式变得越来越多样化。行车记录仪录制的行车视频直观地记录了车辆行驶途中发生的道路交通事故,为案件侦查提供证据和线索。本文通过总结一起非正常死亡案件中行车记录仪视频的检验过程,回顾利用影像技术、电子物证技术以及开展现场实验等技术方法进行综合检验,最终查明行车记录仪的工作模式,认定在案发时段行车记录仪没有录制声音,为明确案件性质提供了重要线索。作者在此案件中所使用的检验方法也为行车记录仪视频的检验工作提供了参考。     

Classification algorithm using halftone features of counterfeit bills and CNN

With recent advancements in image processing and printing technology, home printers have improved in performance and grown more widespread. As such, they have been increasingly used in counterfeiting and forgery. Most counterfeit bills in Korea have been created using home scanners and printers. The identification of printer model is thus necessary to rapidly track down criminals and solve crimes. Household printers can be largely divided into inkjet and laser printers. These two types of printers print halftone textures instead of continuous images. This study proposed a technique of printer classification based on halftone textures that can be observed in printed documents. Since halftone textures are expressed as periodic lattices, the images were transformed via FFT, which is highly effective at expressing periodicity. ResNet, known for its superior gradient flow, was used for training. The experiment was conducted on 12 color laser jets and 2 inkjets. Scans of bills printed by each printer were used, and halftone texture analysis was performed on these images for printer model classification. Each image was cropped into several parts; one of the cropped parts was analyzed. The analysis showed that laser printers could be 100% distinguished from inkjet printers. An accuracy of 98.44% was achieved in make classification. When 50 cropped images were used instead of a single image, the technique achieved 100% accuracy in model classification. The proposed technique is non-destructive; it offers high accessibility and efficiency as it can be performed using a scanner alone, without requiring additional optical equipment.     

Human height estimation from highly distorted surveillance image

Video surveillance camera (VSC) is an important source of information during investigations especially if used as a tool for the extraction of verified and reliable forensic measurements. In this study, some aspects of human height extraction from VSC video frames are analyzed with the aim of identifying and mitigating error sources that can strongly affect the measurement. More specifically, those introduced by lens distortion are present in wide-field-of-view lens such as VSCs. A weak model, which is not able to properly describe and correct the lens distortion, could introduce systematic errors. This study focuses on the aspect of camera calibration to verify human height extraction by Amped FIVE software, which is adopted by the Forensic science laboratories of Carabinieri Force (RaCIS), Italy. A stable and reliable approach of camera calibration is needed since investigators have to deal with different cameras while inspecting the crime scene. The performance of the software in correcting distorted images is compared with a technique of single view self-calibration. Both approaches were applied to several frames acquired by a fish-eye camera and then measuring the height of five different people. Moreover, two actual cases, both characterized by common low-resolution and distorted images, were also analyzed. The height of four known persons was measured and used as reference value for validation. Results show no significant difference between the two calibration approaches working with fish-eye camera in test field, while evidence of differences was found in the measurement on the actual cases.     

The effect of household corrosive substances on latent fingermark development in the context of deliberate corrosive substance attacks

Corrosive substance attacks (CSA) are a prevalent issue in the UK with 525 offenses involving a corrosive substance reported to the police in the year ending March 2022. Easy availability, low cost, and concealability in public are common reasons for choosing a corrosive substance as a weapon. The Metropolitan Police revealed that 68% of 1849 CSA cases resulted in no suspect identified or evidential difficulties. There is limited research into the effect of corrosive substances on latent fingermarks. This study aimed to determine the potential for fingermarks to be recovered from surfaces exposed to a household corrosive substance within the context of a deliberate CSA. Natural and sebaceous-loaded fingermarks were exposed to Domestos bleach, Harpic limescale remover (hydrochloric acid-based) and lemon juice. Harpic limescale remover had the most detrimental effect, with only 7.1% of fingermarks (n = 378) exposed being identifiable (defined as sufficient clear ridge detail for identification) after enhancement, followed by bleach with only 10.3% of fingermarks (n = 378) identifiable. Lemon juice had the least detrimental effect on fingermarks, with 40.5% fingermarks (n = 378) identifiable compared to 53.4% for the controls (not exposed to any substance; n = 378). Throughout the study, fewer natural fingermarks were identifiable after exposure to corrosive substances compared to sebaceous fingermarks which was as expected. Overall, this study demonstrated that there is potential to recover latent fingermarks, depending on their composition, following exposure to a household corrosive substance. This area warrants further research to establish best practice to maximize the potential to recover identifiable fingermarks.     

撕脱骨折与永存骨骺、籽骨、副骨的影像学鉴别

目的探讨撕脱性骨折与永存性骨骺、籽骨、副骨的影像学鉴别办法。方法回顾性分析了14个要求重新鉴定是否存在骨折的案例,观察撕脱性骨折的直接、间接征象,并结合其发生机制与永存性骨骺、籽骨及副骨的固有形态、特点等进行对照。结果所选案例中有2例永存性骨骺、3例籽骨、3例副骨均具有骨块边缘钝圆、骨皮质连续、局部软组织未见肿胀以及伤后该骨的连续摄片无明显变化等共同特征。结论正确掌握撕脱性骨折、生理性小骨骺、籽骨及解剖变异的副骨的特点,并综合运用影像学资料是鉴别撕脱性骨折的基本要素。     

监狱公众形象建设研究

为弘扬社会主义法治精神,践行行刑正义、人权、文明、法治的现代司法理念,重塑中国监狱全新形象,加强和改进监狱公众形象建设,分析和研究监狱公众形象的基本特征,认识监狱公众形象建设的战略意义,探索监狱公众形象建设的有效途径成为当务之急,也是培育中国先进监狱文化的应有之义.     

关于刑案现场数码影像资料采集与存储新方式的研讨

在全面推广使用数码摄影技术的今天,对于刑事案件现场勘查中所摄的能够证明一定犯罪事实成立的案件现场数码原版照片资料,采用何种方式保存更具有永久性,防止被加工与修改的可能？按照怎样的工作流程进行,从搜集与保全证据的角度上看,其程序更具有合法性、可操作性呢？对此学术讨论一直没有一个定论。刑事案件现场影像资料应面对证人采集与多介质临场存储。     

迟滞与觉醒——论当代女工形象的性别书写

当代女工形象的性别书写大致可以分为压抑期、萌芽期、生长期三个阶段,人物形象的特征及作家写作立场的变化反映了不同历史时期、不同的人对女工乃至现代化进程中的人的认知与想象.当代女工形象的性别书写对于工人形象的丰富和深化,以及女性文学的发展都具有重要意义.     

The overweight female body in Malaysian slimming advertisements: problem and solution

This study analyses image and text to investigate the way slimming advertising exploits women’s fear of being overweight to the extent that they feel obliged to do something about their own bodies. We show how Malaysian slimming advertisements construct certain types of female body which reinforce cultural stereotypes, namely the overweight body that exceeds culturally acceptable limits of desirable body size, and the desirable and attainable slim body with no excess fat. Three sample advertisements were selected from a Malaysian English newspaper and analysed using Jewitt and Oyama’s framework to identify the way images and text are used to give specific meanings relating to the female body. The images were examined in terms of representational, interactional and compositional meanings, and the analysis provides evidence of how the extremely overweight female body is pathologised, making it the focus of critical scrutiny. The advertisements use body images to illustrate the problem of being very overweight and the desirability of being slim, and the consumption of slimming services as a quick and easy solution to the problem.