Recovery via SfM photogrammetry of latent footprint impressions in carpet

Authors: Larsen, H.J., Budka, M. and Bennett, M.R.

Journal: Journal of Forensic Sciences

Volume: 66

Issue: 4

Pages: 1495-1505

eISSN: 1556-4029

ISSN: 0022-1198

DOI: 10.1111/1556-4029.14718

Abstract:

Impression evidence retained in carpet is usually recovered, if at all, in two dimensions via a vertical photograph. Here, we show that recovery is also possible via SfM photogrammetry and this gives good quality results that allow digital measurements both in the x-y plane and by depth (z-axis). This study focuses on recovery from polypropylene carpets which are widespread due to their resistance to wear and low cost. We show how traces can be recovered using both SfM photogrammetry and conventional photography with illumination provided via a crime scene light source. Experiments show that traces are retained for considerable time periods if left undisturbed, in excess of four weeks, but are quickly lost in under 8 hours by subsequent footfall. A simple simulation shows how the movement of an individual can be determined from carpet traces and the value of 3D recovery is illustrated via a set of experiments conducted with barefoot traces. We draw attention to the fact that 3D models allow a more statistical-based approach to be taken to match bare footprints at crime scenes. SfM photogrammetry is shown to provide a useful compliment to existing techniques and therefore worthy of further experimentation and potentially operational use.

http://eprints.bournemouth.ac.uk/35420/

Source: Scopus

Recovery via SfM photogrammetry of latent footprint impressions in carpet.

Authors: Larsen, H.J., Budka, M. and Bennett, M.R.

Journal: J Forensic Sci

Volume: 66

Issue: 4

Pages: 1495-1505

eISSN: 1556-4029

DOI: 10.1111/1556-4029.14718

Abstract:

Impression evidence retained in carpet is usually recovered, if at all, in two dimensions via a vertical photograph. Here, we show that recovery is also possible via SfM photogrammetry and this gives good quality results that allow digital measurements both in the x-y plane and by depth (z-axis). This study focuses on recovery from polypropylene carpets which are widespread due to their resistance to wear and low cost. We show how traces can be recovered using both SfM photogrammetry and conventional photography with illumination provided via a crime scene light source. Experiments show that traces are retained for considerable time periods if left undisturbed, in excess of four weeks, but are quickly lost in under 8 hours by subsequent footfall. A simple simulation shows how the movement of an individual can be determined from carpet traces and the value of 3D recovery is illustrated via a set of experiments conducted with barefoot traces. We draw attention to the fact that 3D models allow a more statistical-based approach to be taken to match bare footprints at crime scenes. SfM photogrammetry is shown to provide a useful compliment to existing techniques and therefore worthy of further experimentation and potentially operational use.

http://eprints.bournemouth.ac.uk/35420/

Source: PubMed

Recovery via SfM photogrammetry of latent footprint impressions in carpet

Authors: Larsen, H.J., Budka, M. and Bennett, M.R.

Journal: JOURNAL OF FORENSIC SCIENCES

Volume: 66

Issue: 4

Pages: 1495-1505

eISSN: 1556-4029

ISSN: 0022-1198

DOI: 10.1111/1556-4029.14718

http://eprints.bournemouth.ac.uk/35420/

Source: Web of Science (Lite)

Recovery via SfM photogrammetry of latent footprint impressions in carpet.

Authors: Larsen, H.J., Budka, M. and Bennett, M.R.

Journal: Journal of forensic sciences

Volume: 66

Issue: 4

Pages: 1495-1505

eISSN: 1556-4029

ISSN: 0022-1198

DOI: 10.1111/1556-4029.14718

Abstract:

Impression evidence retained in carpet is usually recovered, if at all, in two dimensions via a vertical photograph. Here, we show that recovery is also possible via SfM photogrammetry and this gives good quality results that allow digital measurements both in the x-y plane and by depth (z-axis). This study focuses on recovery from polypropylene carpets which are widespread due to their resistance to wear and low cost. We show how traces can be recovered using both SfM photogrammetry and conventional photography with illumination provided via a crime scene light source. Experiments show that traces are retained for considerable time periods if left undisturbed, in excess of four weeks, but are quickly lost in under 8 hours by subsequent footfall. A simple simulation shows how the movement of an individual can be determined from carpet traces and the value of 3D recovery is illustrated via a set of experiments conducted with barefoot traces. We draw attention to the fact that 3D models allow a more statistical-based approach to be taken to match bare footprints at crime scenes. SfM photogrammetry is shown to provide a useful compliment to existing techniques and therefore worthy of further experimentation and potentially operational use.

http://eprints.bournemouth.ac.uk/35420/

Source: Europe PubMed Central

Recovery via SfM photogrammetry of latent footprint impressions in carpet.

Authors: Larsen, H.J., Budka, M. and Bennett, M.R.

Journal: Journal of Forensic Sciences

Volume: 66

Issue: 4

Pages: 1495-1505

ISSN: 0022-1198

Abstract:

Impression evidence retained in carpet is usually recovered, if at all, in two dimensions via a vertical photograph. Here, we show that recovery is also possible via SfM photogrammetry and this gives good quality results that allow digital measurements both in the x-y plane and by depth (z-axis). This study focuses on recovery from polypropylene carpets which are widespread due to their resistance to wear and low cost. We show how traces can be recovered using both SfM photogrammetry and conventional photography with illumination provided via a crime scene light source. Experiments show that traces are retained for considerable time periods if left undisturbed, in excess of four weeks, but are quickly lost in under 8 hours by subsequent footfall. A simple simulation shows how the movement of an individual can be determined from carpet traces and the value of 3D recovery is illustrated via a set of experiments conducted with barefoot traces. We draw attention to the fact that 3D models allow a more statistical-based approach to be taken to match bare footprints at crime scenes. SfM photogrammetry is shown to provide a useful compliment to existing techniques and therefore worthy of further experimentation and potentially operational use.

http://eprints.bournemouth.ac.uk/35420/

Source: BURO EPrints