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Over the last few years I have become involved in this area using certain podiatry observational skills to help police in their enquiries, either to eliminate or implicate an individual. In particular I have used gait and posture as the tool for analysing CCTV.
Whilst I have my own, many, questions over this area and begun writing my own little framework for its use I would like to open this out a little and see if you can bring in put for me by exploring some of the follpwing questions:
1. Do you think it is possible?
2. What main markers would you use for identification?
There are other questions but these two are important to start with.
Hi Ian,
I think gait and posture may be useful identifiers when combined with other factors (type of clothing worn/height of subject).
Just an amateur observation you understand :) .
Cheers,
David
Hi there, Mr Willie Kerr at Queen Margaret University Edinburgh, is the man you should talk to, if i remember right he has done major study in this area, you should be able to get his email from the university web site.
forensic podiatry is used widely! and is an up and coming area of study!
Another name of note in this field is Dr wesley Vernon who I think is based in Sheffield but has also recently joined the team at Staffordshire University(who run the MSc in Clinical Biomechanics).
If you know of any key papers in this field could you post them up here? I'm sure I'm one of many who would enjoy reading them
I have been concerned that when studying gait for identification purposes (in CCTV analysis) there has been a narrowing of the field.
e.g. use of the degree of genu varum alone etc
To that extent I have tried to combine postural and gait parameters to develope a system of creating as many identifying markers as possible, against which to make a comparison between a known and unknown person.
Gait and CCTV Analysis sounds good. I have seen a TV. Doc. where a Forensic Podiatrist/pathologist was used by police to examine feet. (USA?), where a couple of fractures had occurred in the bones of the feet! X-Rays had been taken at the local hospital! The skeleton was identified by comparison similar to Forensic Dentist and teeth.
I had a woman fished out of the river, our forensic Dentist identified her by taking a cast of the teeth and traced a possible missing persons dentist and her dental record's! Application to feet perhaps. A sequel to this I still don't know how my hands ended up down her throat holding the dentist's Silicone mould, crafty he was but brilliant at his work for us, Mr. Jackson I think was his name?
Forensic Podiatry was done by our support 'Home Office Forensic Scientist' in my time! Damage to foot wear showing up in fingerprint powder then compared to suspects shoes,(Like car tyre and scene mark!).
One of the classics 1930's something was a thief who broke into a house and found some new shoes, he swapped them for his old ones and left them behind at the scene! The Scientist removed the uppers, caste them and the feet of the thief, (Bumps and hollows, particularly the metatarsal joints!). Perfect fit Jailed on the evidence!
Footprints rare. Thieves were so inconsiderate, they would wear shoes you know! Have been caught when they took off their shoes to walk quietly in burglary though!!! Sixteen plus identification points, better than fingerprints! Today possible traces of DNA from sweaty feet and sweaty shoes possible, perhaps???
The way a villain walkers with gait abnormalities possible I'm sure!
History Ian rather than direct application I'm afraid, hope it's useful. Stance and gait I'm sure holds prospects on the new spy in the sky! Forensic Science used to be a closed sacred territory, different today perhaps?
Regards,
Colin.
PS. Det. Supt. borrowed my books, last I saw of them, typical! I'm sure Google might help?
Having done several cases of this now I am of the view that gait alone must have an extreme unusuality about it to be suffiencient for identification. For this reaon I have tended to apply the combination of posture and gait. This allows for you to observe postural alignments and movements and combine it with information from the individuals gait.
There are hugely significant issues to be aware of.
Yes I'm afraid so we used to be always looking for the unusual all the time to raise the value of the evidence! Splayed foot for instance, never mind the Latin! Usually the Scientific Aids Officers specialized in the recovery of footprints, (Plaster casting etc.?), but normal surfaces would not give you the detail you needed for top value evidence the 'Physical Fit'? The splay also destroyed the detail in the print because he was walking scrubbing his foot to stop falling over!
Identification on camera, physical and demeanour helpful possibly crucial as we have just seen as we watch TV. (No discussion, details, please here Ian!).
A good Q.C. and there are a few of them about, (Now that one could be risky and duly noted!), can really take pleasure in having a go at the expert witness! It's not all sweetness and roses?
Regards,
Colin.
PS. Sherlock Holmes rides again! The writer really did know what he was talking about even if traditionally the Force usually used to talk him down even in my time!
The forensic analysis of soils and sediment taken from the cast of a footprint.
Bull PA, Parker A, Morgan RM. Forensic Sci Int. 2006 Aug 16
Quote:
The routine production of a cast of a shoe-print taken in soil provides information other than shoe size and gait. Material adhering to the surface of the cast represents the preservation of the moment of footprint impression. The analysis of the interface between the cast and soil is therefore a potentially lucrative source of information for forensic reconstruction. These principles are demonstrated with reference to a murder case which took place in the English Midlands. The cast of a footprint provided evidence of a two-way transfer of material between the sole of a boot and the soil of a recently ploughed field. Lumps of soil, which had dried on a boot, were deposited on the field as the footprints were made. Pollen analysis of these lumps of soil indicated that the perpetrator of the imprint had been standing recently in a nearby stream. Fibre analysis together with physical and chemical characteristics of the soil suggested a provenance for contamination of this mud prior to deposition of the footprint. Carbon/nitrogen ratios of the water taken from the cast showed that distilled water had been used thus excluding the possibility of contamination of the boot-soil interface. It was possible to reconstruct three phases of previous activity of the wearer of the boot prior to leaving the footprint in the field after the murder had taken place. This analysis shows the power of integrating different independent techniques in the analysis of hitherto unrecognised forensic materials.
Ian,
I am interested in evaluating a suspect, you can assess the gait pattern, when subjects wear different clothing,long coats, run, carry a bag, rucksack etc...
The perceived angle of viewing and parallax error is particularly great.
As an aside, much work has been done on the ear as identification tool!!
Apparently very individual!
The ear, or at least a particular part of the ear, was a key in identifying the possibility of whether an individual was one of Sadam Husseins sons or not. Apparently it is exceedingly difficult to alter it, even with plastic surgery.
From your opening are you saying you are actually doing an analysis?
Forensic podiatry a small, but potentially useful specialty using clinical podiatric knowledge for the purpose of person identification. The practice of forensic podiatry began in the early 1970s in Canada and the UK, although supportive research commenced later in the 1990s. Techniques of forensic podiatry include identification from podiatry records, the human footprint, footwear, and the analysis of gait forms captured on Closed Circuit Television Cameras. The most valuable techniques relate to the comparison of the foot impressions inside shoes. Tools to describe, measure and compare foot impressions with footwear wear marks have been developed through research with potential for further development. The role of forensic podiatrists is of particular value when dealing with variable factors relating to the functioning and the shod foot. Case studies demonstrate the approach of podiatrists, in footwear identification, when comparing exemplar with questioned foot impressions. Forensic podiatry practice should be approached cautiously and it is essential for podiatrists undertaking this type of work to understand the context within which the process of person identification takes place.
Analysis of footprints can reveal very important clues which can be used as forensic evidence in crime scene investigation. Apart from giving idea about the bare foot morphology and individualistic characteristics, the footprints are also indicative of the body size of the person. The present study is an attempt to establish the correlation between footprints and body weight of individuals. The sample for the present study consists of 50 male subjects ranging in age from 18 to 30 years. The subjects belonging to Gujjar caste were randomly taken from a village near Chandigarh city in North India. Three kinds of bilateral footprints were taken from each subject. First, the footprints with the subject's normal weight were taken, the footprints were taken when the subject holds 5kg weight in his hands, then the footprints were taken when the subject holds 20kg weight in his hands. In this way, the present study analyses 300 bilateral footprints obtained from 50 individuals. Nine measurements were taken on each footprint using precise and defined landmarks. The measurements of these three kinds of footprints were compared with each other and t-test was employed to see the significant variation. Some of the measurements of the footprints were altered significantly when the subject was subjected to 20kg weight. However, there is no significant change when the subject holds 5kg weight in his hands. Body weight was also estimated using regression method from the measurements of these three kinds of footprints. The utility of the study in offences like sexual assault, homicide, theft, burglary, mugging, stealing, shoplifting, dacoity, etc. has been discussed.
Identification of Sex Depending on Radiological Examination of Foot and Patella.
Abdel Moneim WM, Abdel Hady RH, Abdel Maaboud RM, Fathy HM, Hamed AM Am J Forensic Med Pathol. 2008 Jun;29(2):136-140
Quote:
Forensic anthropology involves the building of an antemortem profile of an individual from skeletal remains. This includes sex, race determination, and age and stature estimation. Because most bones that are conventionally used for sex determination are often recovered either in a fragmented or incomplete state, it has become necessary to use denser bones that are often recovered intact, eg, the patella, calcaneus, and talus. The present work was performed to investigate the possibility of estimation of sex from some radiologic measurements among a known cross-section of Egyptian population. In this study lateral and anteroposterior radiographs of the right foot and knee were made on 160 living unfractured and nonpathologic individuals comprising 80 males and 80 females aged 25 to 65 years referred to the Radiology Department of Assiut University Hospital. Two measurements on right patella (maximum height and maximum width) and 2 measurements of metatarsal bones (length and midshaft diameter), were used to determine sex by univariate and multivariate discriminant analysis. Eighty radiographs of foot and patella of individuals not used in the original sample were randomly selected to test the accuracy of this method. The study revealed that significant sex differences were demonstrated based on these measurements taken on metatarsal bones more than on patella. One function associating 2 parameters (length and midshaft) of the third metatarsal bone obtained the highest value of correct sex determination with rate of 100% accuracy. The multivariate function associating length of the first, third, and fifth metatarsal bones and midshaft of first, second, and fifth metatarsal gave 100% accuracy. Test of multivariate function on the independent sample revealed a correct classification of 87.5%.
Identification of an individual is the mainstay in forensic investigations. The dimensions of the foot have been used for the determination of sex, age, and stature of an individual. The present study examines the relationship between stature and foot dimensions among Gujjars, a North Indian endogamous group. Stature, foot length and foot breadth of 200 subjects comprising 100 males and 100 females were measured. Statistical analyses indicated that the bilateral variation was insignificant for all the measurements except foot breadth in males (p<0.01). Sex differences were found to be highly significant for all the measurements (p<0.01). Linear and multiple regression equations for stature estimation were calculated using the aforementioned variables and multiplication factors were computed. The correlation coefficients between stature and foot dimensions were found to be positive and statistically highly significant. The highest correlation coefficient between stature and foot length in males and foot breadth in females indicates that the foot length provides the highest reliability and accuracy in estimating stature of an unknown male and foot breadth in a female. Prediction of stature was found to be most accurate by multiple regression analysis.
Sex determination by discriminant analysis of calcaneal measurements on the lateral digital radiography
Zhang ZH, Chen XG, Li WK, Yang SQ, Deng ZH, Yu JQ, Yang ZG, Huang L. Fa Yi Xue Za Zhi. 2008 Apr;24(2):122-5.
Quote:
OBJECTIVE: Five measurements of the calcaneus taken on digital radiography (DR) of adults of Han Population of Sichuan Province were selected to determine sex by multivariate discriminant analysis.
METHODS: Lateral radiographs of calcaneus taken from 393 subjects were collected. The samples were randomly divided into the experimental group (148 males and 186 females) and the examined group (26 males and 33 females). Five measurements were taken from the radiography. The analysis of variance (AVON) was carried out to determine if there was significant difference between the male and female. The discriminant functions were drawn by Fisher discriminant analysis. The effects of all obtained functions were evaluated with the examined samples.
RESULTS: There was statistically significant difference in the five measurements between the males and the females (P<0.05). Six groups of discriminant functions were obtained with an accuracy ranged from 78.4% to 88.9%. When applied on the examined samples, the sex discriminant accuracy varied from 79.7% to 86.4%.
CONCLUSION: These five measurements acquired from the lateral radiographs of calcaneus could be used for sex assessment during forensic identification of individuals.
The Post Tribune are reporting: If the shoe fits... Crown Point podiatrist fighting crime
Quote:
Podiatrist Michael Nirenberg is putting his foot down when it comes to crime.
He has embarked on a journey to help law enforcement narrow down suspects in crimes and does it by looking at shoes.
It all started in 1989 when Nirenberg published a paper on forensic podiatry and won the Distinguished Podiatric Medical Writing Award.
In 2003, the American Society of Forensic Podiatrists was started, and Nirenberg was put on the ASFP Board of Directors. He is also on the subcommittee of the International Association for Identification.
What he does is study the wear patterns in a shoe or shoes left at a crime scene. Everyone has something unique in the way he or she walks. The imprints left in shoes tell a lot about the person who was wearing them.
Nirenberg compares the shoe to the suspect and infers characteristics about him or her.
"It's really exciting to prove if someone is innocent or guilty," he said. "To put someone away or let them go free is a great feeling."
Nirenberg started examining shoes with a dental mirror. While using a high-resolution fiber-optic camera for treating arthritis in ankles, he had an epiphany. The small, durable camera would be ideal for scoping out the inside of a shoe.
Nirenberg's idea has really paid off. The camera helps him look at the whole shoe more thoroughly than a mirror and allows him to videotape the session or take pictures for a jury to view later.
"Studying forensic podiatry allows me to look at feet, footprints and shoes differently than most podiatrists," Nirenberg said. "I am a better problem-solver (for patients) because of it."
Nirenberg said he is one of about 10 forensic podiatrists in the world. He has helped on a murder case in Kentucky and is working on one in Indiana.
Nirenberg has lectured to local and state law enforcement officials, Homeland Security and other podiatrists in Indiana. He will lecture locally in August.
Nirenberg also used his forensic podiatry skills to help save a man's life by discovering that his foot pain was due to a tumor in his neck.
"I wouldn't have been able to discover the real problem if it hadn't been for forensic podiatry," he said. "It has made me a better doctor."
The measurements of feet and footprints are especially important in forensic identification, as they have been used to predict the body height and weight of victims or suspects. It can be observed that the subjects of forensic-oriented studies are generally young adults. That is to say, researchers rarely take into consideration the body's proportional changes with age. Hence, the aim of this study is to generate equations which take age and sex into consideration, when stature and body weight are estimated from foot and footprints dimensions. With this aim in mind, we measured the stature, body weight, foot length and breadth, heel breadth, footprint length and breadth, and footprint heel breadth of 516 volunteers (253 males and 263 females) aged between 17.6 and 82.9 years using standard measurement techniques. The sample population was divided randomly into two groups. Group 1, the study group, consisted of 80% of the sample (n = 406); the remaining 20% were assigned to the cross-validation group or Group 2 (n = 110). In the first stage of the study, we produced equations for estimating stature and weight using a stepwise regression technique. Then, their reliability was tested on Group 2 members. Statistical analyses showed that the ratios of foot dimensions to stature and body weight change considerably with age and sex. Consequently, the regression equations which include these variables yielded more reliable results. Our results indicated that age and sex should be taken into consideration when predicting human body height and weight for forensic purposes.
As the most common type of evidence at crime scenes, footwear marks are found more often than fingerprints, and yet left largely unused due to lack of efficient and reliable tools. While the central task is stated simply - retrieve the closest matches among a database of known outsole prints - the difficulty is the poor quality of the marks and a very large and increasing number of outsole patterns. Since grouping the database into clusters can dramatically speed-up retrieval, we propose clustering based on recurring outsole patterns. The clustered database is used to retrieve similar prints for a given crime scene mark. Geometric shapes like line segments, circles and ellipses are proposed as features for crime scene marks. Then these features are structurally represented in the form of an attributed relational graph (ARG). Robust ARG matching is achieved with the introduced footwear print distance (FPD), a similarity measure for footwear prints. Sensitivity analysis of FPD is performed to show its robustness. The proposed system is invariant to scale, translation, rotation and insensitive to noise and degradations of the prints. Experiments show that the approach outperforms other state-of-the-art footwear print retrieval systems.
Press Release: Footwear forensics
CSI needs to tread carefully
Quote:
A new computer algorithm can analyze the footwear marks left at a crime scene according to clusters of footwear types, makes and tread patterns even if the imprint recorded by crime scene investigators is distorted or only a partial print.
Footwear marks are found at crime scenes much more commonly than fingerprints, writes a team from the University at Buffalo, New York, in a forthcoming issue of the International Journal of Granular Computing, Rough Sets and Intelligent Systems. They point out that while footprints are common they are often left unused by forensic scientists because marks may be distorted, only a partial print may be left and because of the vast number of shoe shapes and sizes. However, matching a footprint at a crime scene can quickly narrow the number of suspects and can tie different crime scenes to the same perpetrator even if other evidence is lacking.
The team, Yi Tang, Harish Kasiviswanathan and Sargur Srihari, has developed a way to group recurring patterns in a database of footwear marks to that the clustered data can be searched and compared to suspect prints much more quickly than by other techniques whether manual or computer-based. The team explains that geometric shapes including line segments, circles and ellipses can be the focus and allow the footwear to be quickly identified using an "attributed relational graph" or ARG. The attributes for every shape are defined in a way to provide scaling, rotation and translation invariance, the researchers explain. The team adds that the introduction of a measure of how different two marks might be, which they refer to as the footwear print distance (FPD) allows them to home in on a particular boot or shoe even if the recorded print is noisy or degraded perhaps by perpetrator retracing their steps or other marks present at the scene.
The researchers have successfully tested their approach against the currently used footwear print retrieval systems used in forensic science. "In experimental runs our system has significantly higher accuracy than state-of-the-art footwear print retrieval systems," Tang says.
Estimation of sex of footprints can help in establishing the biological profile of potential suspects. This research attempts to study the sex differences in the ridge density in four different areas of a footprint. The study sample comprises footprints from both feet of 106 adult subjects from India that were analysed using standardized techniques. A total of 212 footprints were studied in detail. The four areas analysed in the study included the upper portion of the medial border of the great toe (F1), the ball of the great toe (F2), the ball of the 5th toe below the triradius point (F3) and the central prominent part of the heel (F4). Male–female differences in footprint ridge density were statistically analysed for each designated area and compared between right and left sides. The mean footprint ridge density was significantly higher among females than males in all designated areas (p < 0.05) in both feet. No right-left differences were apparent in the analysed areas. Variations in footprint ridge density between different areas in right and left feet were evident among males and females. This study observes that sex differences exist in footprint ridge density among humans. Maximum sex differences were observed for ridge density in medial ball area, followed by great toe, lateral ball and minimum sex differences were observed in the heel region. It is observed that sex can be estimated from footprint ridge density with reasonable accuracy. The sexing potential of total footprint ridge density was 82.6% from the right and 83.6% from the left footprints respectively.
Forensic podiatrist Dr Paul Bennett faced lengthy cross-examination from defence lawyer Michael Bosscherover the method he used to determine the Globe sneakers uncovered belonged to Daniel.
The identification of individuals by observational gait analysis using closed circuit television footage
Ivan Birch, Louis Raymond, Anastasia Christou, Milan Angelo Fernando, Nigel Harrison, Flo Paul Science & Justice in press
Quote:
This study investigated the ability of individuals with experience in gait analysis to identify people by observing features of gait recorded by closed circuit television cameras (CCTV). Seven experienced analysts each viewed five samples of footage. Each sample showed a “target walker” and five “suspect walkers.” The task of the experienced analysts was to determine which, if any, of the “suspect walkers” was the “target walker.” All of the participant “walkers” wore identical loose fitting clothing to mask anatomical and body contour features, and balaclavas to obscure facial features. The overall results showed that the experienced analysts made a correct decision in 124 of 175 cases (71%), significantly better than would have been expected to have occurred by chance (p < 0.05). A significant variation in correct decisions (p < 0.05) was shown to occur between the various angles from which the footage was recorded, footage recorded in the saggital plane showing the highest number of correct decisions. Significantly more correct decisions (p < 0.05) were also shown to occur when the footage of the “target walker” and that of the “suspect walker” were taken from the same angle. The results suggest that individuals with experience in gait analysis perform well in the comparative identification of suspects from CCTV footage, and therefore do have a role to play as expert witnesses in this field.
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