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.     

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.     

Body height estimation based on dimensions of sacral and coccygeal vertebrae

This study is to evaluate whether it is possible to predict living stature from sacral and coccygeal vertebral dimensions. Individual vertebral body heights, sacral height (SH), and sacrococcygeal height (SCH) were recorded from the magnetic resonance images of 42 adult males. Sum of the heights of five sacral vertebrae (sigmaS), the first four coccygeal vertebrae (sigmaC), and the total height of the sacral and the first four coccygeal vertebrae together (sigmaSC) were also recorded. Linear regression equations for stature estimation were produced using the above mentioned variables. The regression equations were constructed and tested by using jack-knife procedure. Statistical analyses indicated that the combined variables (SH, SCH, sigmaS, sigmaC, sigmaSC) were more accurate predictors of stature than the heights of individual vertebrae. The results of the study pointed out that the equations derived from sacrococcygeal dimensions perform somewhat better than ones based on foot and head variables, but worse than those based on long-bone length. As a conclusion, the dimensions of sacral and coccygeal vertebrae could be used for stature estimation when long bones are not available.     

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.     

数字X线摄影测量活体脊柱胸段推算身高

目的建立人脊柱胸段长度推算身高的方法。方法应用数字X线摄影技术（DR）摄制514例中国四川汉族人群的胸部DR片，测其脊柱胸段长度，同时准确测量被研究者身高，对测量获得的脊柱胸段长度与身高数据分组进行线性回归分析，建立胸段长度推算身高的回归方程。结果建立了混合组、男性组、女性组、20—45岁男性组、大于45岁男性组、20～45岁女性组和大于45岁女性组7个回归方程，经显著性检验，均有统计学意义（P〈0．01），复相关系数（R）范围0．834～0．624，回归系数（b）范围0．259～0．389，回归方程估计值的标准误在3．88～4．72cm范围内。结论利用人类脊柱胸段长度推算身高的方法在法医学个人识别中具有重要价值。     

A preliminary test of Pearson's formula for estimation of height of Sri Lankans

The validity of Pearson's formula for estimation of height from the length of bones, has not been tested for Sri Lankan populations. Such a validation was attempted on 27 male cadavers using the recumbent heel to vertex height, and the physiological femoral length. The standard Pearson's formula was found to contain an error in the tested population. Based on these findings, a new formula was therefore evolved where S = 27.48 + 3.08F (as opposed to S = 81.306 + 1.88F in the standard formula). The new formula will be tested further on a larger sample, with a view to making further indicated adjustments.     

The effect of frame rate on the ability of experienced gait analysts to identify characteristics of gait from closed circuit television footage

Forensic gait analysis is increasingly being used as part of criminal investigations. A major issue is the quality of the closed circuit television (CCTV) footage used, particularly the frame rate which can vary from 25 frames per second to one frame every 4 s. To date, no study has investigated the effect of frame rate on forensic gait analysis. A single subject was fitted with an ankle foot orthosis and recorded walking at 25 frames per second. 3D motion data were also collected, providing an absolute assessment of the gait characteristics. The CCTV footage was then edited to produce a set of eight additional pieces of footage, at various frame rates. Practitioners with knowledge of forensic gait analysis were recruited and instructed to record their observations regarding the characteristics of the subject's gait from the footage. They were sequentially sent web links to the nine pieces of footage, lowest frame rate first, and a simple observation recording form, over a period of 8 months. A sample-based Pearson product-moment correlation analysis of the results demonstrated a significant positive relationship between frame rate and scores (r = 0.868, p = 0.002). The results of this study show that frame rate affects the ability of experienced practitioners to identify characteristics of gait captured on CCTV footage. Every effort should therefore be made to ensure that CCTV footage likely to be used in criminal proceedings is captured at as high a frame rate as possible.     

Estimating height and weight from size of footprints

In the mid 1800s, Topinard proposed a simple formula for estimating a person's height: maximum foot length divided by 0.15 reveals the stature of most individuals. In addition to corroborating Topinard's findings, the author has developed formulas to serve as predictive models for estimating both height and weight when only a subject's footprint dimensions are known. The formulas are presented with a discussion of the data from which they are derived.     

Classification of falling from a height

A classification of falling from a height is suggested; it involves different factors and conditions influencing the infliction of injuries: presence or absence of a preliminary acceleration and of possible obstacles in the body flight route; landing surface properties and a height of falling etc. A study and analysis of published data and author's independent observations provided a basis for the classification.     

Mixed effects modelling for glass category estimation from glass refractive indices

520 Glass fragments were taken from 105 glass items. Each item was either a container, a window, or glass from an automobile. Each of these three classes of use are defined as glass categories. Refractive indexes were measured both before, and after a programme of re-annealing. Because the refractive index of each fragment could not in itself be observed before and after re-annealing, a model based approach was used to estimate the change in refractive index for each glass category. It was found that less complex estimation methods would be equivalent to the full model, and were subsequently used. The change in refractive index was then used to calculate a measure of the evidential value for each item belonging to each glass category. The distributions of refractive index change were considered for each glass category, and it was found that, possibly due to small samples, members of the normal family would not adequately model the refractive index changes within two of the use types considered here. Two alternative approaches to modelling the change in refractive index were used, one employed more established kernel density estimates, the other a newer approach called log-concave estimation. Either method when applied to the change in refractive index was found to give good estimates of glass category, however, on all performance metrics kernel density estimates were found to be slightly better than log-concave estimates, although the estimates from log-concave estimation prossessed properties which had some qualitative appeal not encapsulated in the selected measures of performance. These results and implications of these two methods of estimating probability densities for glass refractive indexes are discussed.     

Preliminary report on a new method of human age estimation from single adult teeth.

A total of 317 upper and lower third molars were randomly divided into working and control samples and used to estimate chronological age employing a method which combined multiple regression analysis of data from Gustafson's and Maples's scoring system, direct morphological measurements obtained with a Kontron image analysis system and logarithmic data transformation. The standard errors of estimate were 2.4-6.8 years in the working sample and 1.9-7.5 years when the derived formulae were tested on the control sample, respectively. Compared to previous studies, this method provides a smaller standard error of estimate from a single molar tooth. The method is presently being tested on other tooth categories, like premolars, canines and other types of molars.     

The effects of skeletal preparation techniques on DNA from human and non-human bone

The forensic pathologist increasingly relies on the forensic anthropologist to be the consulting expert in human identification. Likewise, if identification is not possible from visual inspection of skeletal remains, the forensic biologist may be called upon to conduct DNA analysis. The possibility of downstream DNA testing needs to be considered when skeletal preparation techniques are employed to deflesh human remains, as they have the potential to strongly impact genetic analyses and subsequent identification. In this study, three cleaning techniques, boiling bone in water, in bleach, and in powdered detergent/sodium carbonate, were tested for their effect on nuclear and mtDNA recovery from a variety of human and non-human bones. A statistically significant reduction in DNA yields occurred in non-human bones cleaned with bleach, and DNA degradation was apparent electrophoretically. The human bones also showed much lower yields from bleach cleaning, while the detergent/carbonate method allowed the largest segments of DNA to be amplified, indicating it may have a less degradative effect on bone DNA than either of the other cleaning processes.     

利用人体标本进行死亡时间推断的研究现状

死亡时间(PMI)推断具有重要的法医学意义,但尚无可以应用在实践领域的PMI推断方法。本文从PMI推断的实践应用角度出发,从脏器、骨骼、骨骼肌、牙齿、牙龈以及大体观、毛发、皮肤和血液等角度,对利用人体标本进行死亡时间推断的研究现状进行了综述。希望对我国开展人体标本的PMI推断实践研究提供借鉴。     

A new method of age estimation based on the changes in human non-collagenous proteins from dentin

The new method exploits the characteristic of staphylococcal protease V8, which specifically splits peptide bonds where l-glutamic or l-aspartic acid participate. Those peptide bonds where d-aspartic acid is present remain unsplit because of the stereospecifity of enzymes. In accordance with expectations, fewer peptide bonds are split by this protease at more advanced ages and larger peptide fragments are thus formed due to the higher content of d-amino acid residues in the proteins of older people. The samples of acid-extracted non-collagenous proteins from dentin were separated using high performance liquid chromatography after enzymatic hydrolysis. A peak with a retention time of 45.3 min was chosen and his enlarging area showed a linear correlation with increasing age. Although the linear correlation with age was proved, the scattering of values decreases the usefulness of the proposed method for age estimation.     

Pathologic features of fatal falls from height

Deaths due to falls from height are common in urban settings. At the time the body is found, it is often unclear whether the mode of death is accident, suicide, or homicide. To assess the injury pattern in fatal falls from height with special regard to criteria that might be helpful in discrimination between accident, suicide, and homicide, respectively, we reviewed 68 medicolegal autopsy cases (22 females, 46 males, age range 13-89 years) of fatal falls from height regarding demographic data, findings at the death scene, results of the postmortem examination, psychiatric history, and toxicologic findings. Among the 68 cases, there were 34 suicides, 23 accidents, and 11 unclarified cases, in 3 of which homicide was suspected. In general, suicides were from greater heights than accidents (mean height 22.7 m for suicides and 10.8 m for accidents, respectively; 79% of suicides from more than 16 m). Strikingly, severe head injuries predominantly occurred in falls from heights below 10 m (84%) and above 25 m (90%), whereas in the group of falls from 10 to 25 m, these lesions were seen less frequently (28%). Neck injuries like muscle bleeds and fractures of the hyoid bone were found in 33% of falls from more than 10 m and did not occur from less than 10 m. Our data stress that the evaluation of pathologic features alone is not sufficient to assess the mode of death in fatal falls from height. Instead, postmortem findings have to be considered within the framework of the subject's social, medical, and psychiatric history in conjunction with findings at the death scene and toxicology results to obtain the clearest possible picture of the circumstances of death.     

Racemization of aspartic acid from human dentin in the estimation of chronological age

The estimation of chronological age in cadavers, human remains and in living human beings by various methods is discussed. These methods, which are based on the age dependent non-enzymatic changes of l-form amino acids to d-form amino acids, mainly aspartic acid, are among the most reliable and accurate methods to date. Most of these methods use gas chromatography (GC). In this review, results of aspartic acid racemization in dentin at different targets are discussed. In addition, pre-considerations and guidelines are given for the selection of dentin from teeth. A pilot project was run to evaluate the efficiency of high performance liquid chromatography (HPLC) coupled with fluorescence detection. New buffer conditions were found to obtain stable derivatives of aspartic acid enantiomers for the estimation of racemization.     

Mandibular ramus height as an indicator of human infant age

There were two goals to be achieved from the analysis of 53 skeletonized infants from the Southwest Collection at the National Museum of Natural History. The first objective was to determine whether this infant sample could be aged based on a mandibular measurement. The second was to determine which dimension of the mandible, if any, most accurately predicts infant age within a six-month range. Seven osteometric measurements were applied to each mandible. Statistical analysis determined that the individuals in the Smithsonian's Southwest Collection that were under two-years-old could be accurately aged to within six months. Out of these seven measurements the most accurate age-at-death estimates were generated based on the maximum height of the mandibular ramus. This finding can potentially aid investigators in determining the age-at-death of infants.     

Age estimation from the human os coxa: a test on a documented Italian collection*

Current standards for age at death estimation from the pelvis are based on Americans of European and African ancestry. Our limited understanding of population variability hampers our efforts to apply these techniques to the various skeletal populations around the world, especially in global forensic contexts. However, documented skeletal samples are rare, limiting our ability to test our techniques. This study tested the Suchey-Brooks pubic symphysis aging method and the auricular surface method originally developed by Lovejoy et al. on a large sample (n = 404) of known sex and age from the Sassari Collection, housed at the Museum of Anthropology at the University of Bologna, Italy. The results indicate that for both methods, bias and inaccuracy increased with age and actual age tended to be underestimated over the age of 40. The auricular surface method performed slightly better, exhibiting slightly lower levels of bias and inaccuracy, especially for males.     

Study on the effects of heat on blood and on the post-mortem estimation of carboxyhaemoglobin and methaemoglobin

Blood samples of different carboxyhaemoglobin (CoHb) content (0%, 50%, 100%) were analysed, after short exposure to heat, for determination of the change of CoHb and methaemoglobin (MetHb) during the succeeding 14 days. Untreated blood showed an initial increase of MetHb after heating followed by a decrease during this period. There was no formation of CoHb in the untreated blood. When CoHb was already present in the blood the amount of MetHb was smaller in amount and was formed at a slower rate. In these samples the concentration of CoHb slowly decreased.     

Variability of the pattern of aging on the human skeleton: evidence from bone indicators and implications on age at death estimation

Age at death assessment of adult skeletons is one of the most difficult problems in forensic and physical anthropology. Two fundamental sources of error are described: the complex variability in the process of skeletal aging and methodological bias. Taking into account these limits, we developed a new scoring system for the auricular surface of the ilium and the pubic symphysis. In order to address a large variability, we examine reference samples from Europe, North America, Africa, and Asia. Data were processed using Bayesian prediction in order to classify specimens in age range categories. Results show that combining indicators do not perform better than the auricular surface used as a single indicator. Morphological changes with aging are variable between Asian, African, and European populations, confirming the necessity to use population-specific standards. Bayesian prediction produces reliable classification and is applicable for subjects over 50 years old, a real methodological improvement.