Teghan Lucas - Academia.edu (original) (raw)

Papers by Teghan Lucas

Journal of Anthropology, 2016

Forensic science international, Jan 25, 2015

In the forensic sciences it is inferred that human individuals are unique and thus can be reliabl... more In the forensic sciences it is inferred that human individuals are unique and thus can be reliably identified. The concept of individual uniqueness is claimed to be unprovable because another individual of same characteristics may exist if population size were infinite. It is proposed to replace "unique" with "singular" defined as a situation when only one individual in a specific population has a particular set of characteristics. The likelihood that in a population there will be no duplicate individual with exactly the same set of characteristics can be calculated from datasets of relevant characteristics. To explore singularity, the ANSUR database which contains anthropometric measurements of 3982 individuals was used. Eight facial metric traits were used to search for duplicates. With the addition of each trait, the chances of finding a duplicate were reduced until singularity was achieved. Singularity was consistently achieved at a combination of the maximum...

Forensic Science International, 2015

In the forensic sciences it is inferred that human individuals are unique and thus can be reliabl... more In the forensic sciences it is inferred that human individuals are unique and thus can be reliably identified. The concept of individual uniqueness is claimed to be unprovable because another individual of same characteristics may exist if population size were infinite. It is proposed to replace "unique" with "singular" defined as a situation when only one individual in a specific population has a particular set of characteristics. The likelihood that in a population there will be no duplicate individual with exactly the same set of characteristics can be calculated from datasets of relevant characteristics. To explore singularity, the ANSUR database which contains anthropometric measurements of 3982 individuals was used. Eight facial metric traits were used to search for duplicates. With the addition of each trait, the chances of finding a duplicate were reduced until singularity was achieved. Singularity was consistently achieved at a combination of the maximum of seven traits. The larger the traits in dimension, the faster singularity was achieved. By exploring how singularity is achieved in subsamples of 200, 500, etc. it has been determined that about one trait needs to be added when the size of the target population increases by 1000 individuals. With the combination of four facial dimensions, it is possible to achieve a probability of finding a duplicate of the order of 10(-7), while, the combination of 8 traits reduces probability to the order of 10(-14), that is less than one in a trillion.

International Journal of Legal Medicine, 2015

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

Anthropologischer Anzeiger, 2014

Closed circuit television (CCTV) systems are being widely used in crime surveillance. The images ... more Closed circuit television (CCTV) systems are being widely used in crime surveillance. The images produced are of poor quality often face details are not visible, however expert witnesses in the field of biological anthropology use morphological descriptions of body shapes in an attempt to identify persons of interest. These methods can be applied to individual images when other cues such as gait, are not present. Criminals commonly disguise their faces, but body shape characteristics can be used to distinguish a person of interest from others. Garments may distort the body shape appearance, thus this study was undertaken to investigate the effects of garments on the description of body shape from CCTV images. Twelve adult males representing a wide body shape range of Sheldonian somatotypes were photographed in identical garments comprising of tight fitting black shirt, horizontally striped shirt, padded leather jacket and in naked torso. These photographs were assessed by 51 males and females aged 18-50 years, with varying levels of education, and different experience in use of CCTV images for identification of people, to identify the 12 participants. The effect of assessors was not significant. They correctly distinguished 88.6 % of individuals wearing the same wear, but could not match the same individuals wearing different wear above the random expectations. However, they matched somatotypes above random expectation. Type of clothing produced little bias in somatotype matching; ectomorphic component of individuals wearing black shirts and padded jackets was overestimated and underestimated, respectively. In conclusion, type of the wear had little effect in the description of individuals from CCTV images using the body shapes.

Forensic Science International, 2014

Person identification from images is an important task in many security applications and forensic... more Person identification from images is an important task in many security applications and forensic investigations. The essence of the problem comes down to measuring key observable anatomical features which can help describing similarities or differences between two or more individuals. In this paper, we examine how different types of garments affect the placement of body markers that enable precise anatomical human description. We focus in particular on landmark positioning errors on the upper limb. Closed-form formulae are provided to compute the maximum likelihood estimate of upper limb length from an image. Subject stature is then predicted from the limb length through a regression model and used as identification criterion. Following initial laboratory experiments, the technique is demonstrated to be invariant to posture and applicable to uninformed subjects in unconstrained environments. Seven technical errors of measurement and statistical tests are quantified empirically from statures obtained by three assessors. Results show that thicker garments produce higher inaccuracies in landmark localisation but errors decrease as placement is repeated, as expected. Overall, comparison to truth reveals that on average statures are predicted with accuracy in excess of 96% for the worst assessor.

American Journal of Human Biology, 2014

Objectives: The obesity epidemic is impacting both developed and undeveloped countries worldwide.... more Objectives: The obesity epidemic is impacting both developed and undeveloped countries worldwide. It has only been recently that wide scale public campaigning has focused on prevention rather than intervention. Individual variations in food metabolism and energy expenditure may be responsible for much of the adiposity present amongst individuals. This article studies individual variation in relationship between lean trunk size and adiposity.

Journal of Anthropology, 2016

Forensic science international, Jan 25, 2015

In the forensic sciences it is inferred that human individuals are unique and thus can be reliabl... more In the forensic sciences it is inferred that human individuals are unique and thus can be reliably identified. The concept of individual uniqueness is claimed to be unprovable because another individual of same characteristics may exist if population size were infinite. It is proposed to replace "unique" with "singular" defined as a situation when only one individual in a specific population has a particular set of characteristics. The likelihood that in a population there will be no duplicate individual with exactly the same set of characteristics can be calculated from datasets of relevant characteristics. To explore singularity, the ANSUR database which contains anthropometric measurements of 3982 individuals was used. Eight facial metric traits were used to search for duplicates. With the addition of each trait, the chances of finding a duplicate were reduced until singularity was achieved. Singularity was consistently achieved at a combination of the maximum...

Forensic Science International, 2015

In the forensic sciences it is inferred that human individuals are unique and thus can be reliabl... more In the forensic sciences it is inferred that human individuals are unique and thus can be reliably identified. The concept of individual uniqueness is claimed to be unprovable because another individual of same characteristics may exist if population size were infinite. It is proposed to replace "unique" with "singular" defined as a situation when only one individual in a specific population has a particular set of characteristics. The likelihood that in a population there will be no duplicate individual with exactly the same set of characteristics can be calculated from datasets of relevant characteristics. To explore singularity, the ANSUR database which contains anthropometric measurements of 3982 individuals was used. Eight facial metric traits were used to search for duplicates. With the addition of each trait, the chances of finding a duplicate were reduced until singularity was achieved. Singularity was consistently achieved at a combination of the maximum of seven traits. The larger the traits in dimension, the faster singularity was achieved. By exploring how singularity is achieved in subsamples of 200, 500, etc. it has been determined that about one trait needs to be added when the size of the target population increases by 1000 individuals. With the combination of four facial dimensions, it is possible to achieve a probability of finding a duplicate of the order of 10(-7), while, the combination of 8 traits reduces probability to the order of 10(-14), that is less than one in a trillion.

International Journal of Legal Medicine, 2015

Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Ber... more Your article is protected by copyright and all rights are held exclusively by Springer-Verlag Berlin Heidelberg. This e-offprint is for personal use only and shall not be selfarchived in electronic repositories. If you wish to self-archive your article, please use the accepted manuscript version for posting on your own website. You may further deposit the accepted manuscript version in any repository, provided it is only made publicly available 12 months after official publication or later and provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be accompanied by the following text: "The final publication is available at link.springer.com".

Anthropologischer Anzeiger, 2014

Closed circuit television (CCTV) systems are being widely used in crime surveillance. The images ... more Closed circuit television (CCTV) systems are being widely used in crime surveillance. The images produced are of poor quality often face details are not visible, however expert witnesses in the field of biological anthropology use morphological descriptions of body shapes in an attempt to identify persons of interest. These methods can be applied to individual images when other cues such as gait, are not present. Criminals commonly disguise their faces, but body shape characteristics can be used to distinguish a person of interest from others. Garments may distort the body shape appearance, thus this study was undertaken to investigate the effects of garments on the description of body shape from CCTV images. Twelve adult males representing a wide body shape range of Sheldonian somatotypes were photographed in identical garments comprising of tight fitting black shirt, horizontally striped shirt, padded leather jacket and in naked torso. These photographs were assessed by 51 males and females aged 18-50 years, with varying levels of education, and different experience in use of CCTV images for identification of people, to identify the 12 participants. The effect of assessors was not significant. They correctly distinguished 88.6 % of individuals wearing the same wear, but could not match the same individuals wearing different wear above the random expectations. However, they matched somatotypes above random expectation. Type of clothing produced little bias in somatotype matching; ectomorphic component of individuals wearing black shirts and padded jackets was overestimated and underestimated, respectively. In conclusion, type of the wear had little effect in the description of individuals from CCTV images using the body shapes.

Forensic Science International, 2014

Person identification from images is an important task in many security applications and forensic... more Person identification from images is an important task in many security applications and forensic investigations. The essence of the problem comes down to measuring key observable anatomical features which can help describing similarities or differences between two or more individuals. In this paper, we examine how different types of garments affect the placement of body markers that enable precise anatomical human description. We focus in particular on landmark positioning errors on the upper limb. Closed-form formulae are provided to compute the maximum likelihood estimate of upper limb length from an image. Subject stature is then predicted from the limb length through a regression model and used as identification criterion. Following initial laboratory experiments, the technique is demonstrated to be invariant to posture and applicable to uninformed subjects in unconstrained environments. Seven technical errors of measurement and statistical tests are quantified empirically from statures obtained by three assessors. Results show that thicker garments produce higher inaccuracies in landmark localisation but errors decrease as placement is repeated, as expected. Overall, comparison to truth reveals that on average statures are predicted with accuracy in excess of 96% for the worst assessor.

American Journal of Human Biology, 2014

Objectives: The obesity epidemic is impacting both developed and undeveloped countries worldwide.... more Objectives: The obesity epidemic is impacting both developed and undeveloped countries worldwide. It has only been recently that wide scale public campaigning has focused on prevention rather than intervention. Individual variations in food metabolism and energy expenditure may be responsible for much of the adiposity present amongst individuals. This article studies individual variation in relationship between lean trunk size and adiposity.