Sodobna forenzična fotografija

fotografiranje krvnih sledi in sledi obuval

Mitja Ličar (Author), Bojan Dobovšek (Mentor), Katja Drobnič (Co-mentor)

Abstract

V teoretičnem delu avtor predstavi osnove fotografije. Opredeli osnovne parametre za pravilno eksponiranje fotografije, pojem globinske ostrine, predstavi objektive ter del nameni svetlobi, kontrastu vira svetlobe in svetlobnih odbojev. V nadaljevanju specificira fotografijo v forenzični vlogi. Opredeli situacijski posnetek, posnetek relativne bližine in bližnji posnetek. Osredini se na teorijo fotografiranja krvnih sledov. Predstavi problematične površine nahajanja krvnih sledi, uporabo kemijskih reagentov ter za te namene uporabo bliskavice pri fotografiranju. Prav tako se dotakne teorije fotografiranja sledi obuval ter opredeli reliefne in ploske sledi obuval. Na koncu teoretičnega dela se dotakne še digitalnega rokovanja s fotografijami v smislu digitalne postprodukcije. V empiričnem delu se osredini na fotografiranje reliefnih sledi obuval. Pri dveh sledeh istega obuvala z različno debelino podlage in globino ugreza obuvala pri isti strukturi podlage preizkuša, kako kot svetlobe vpliva na prepoznavo karakteristik obuvala na fotografiji. Reagiranje svetlobe na sled preizkuša iz treh različnih položajev po krožnici okrog sledi obuvala iz treh različnih kotov naklona – 25-, 50- in 75-stopinjskega kota vpadne svetlobe. Ob koncu tega dela analizira ugotovitve in poda statistične podatke izraženosti kontrolnih točk glede na globino sledi, položaj in kot svetlobe. Ugotavlja, da sta za fotografiranje profilnih sledi obuval, najbolj ugodna kota vpadne svetlobe, 25 in 50 stopinj. V empiričnem delu opravi tudi poskus fotografiranja krvnih sledi na bombažni tkanini. Za preizkus vzame 5 različnih barv iste tkanine, na katere odtisne krvavo sled obuvala, ki je kontaminirano s svinjsko krvjo. V nadaljevanju sledi fotografira s tremi različnimi tipi svetlobe - LED lučjo, forenzičnim svetlobnim virom pri 415 nm ter forenzičnim svetlobnim virom pri 415 nm z uporabo rumenega filtra na objektivu fotoaparata. Ugotavlja, da se pri eksperimentu najbolj obnese forenzični vir svetlobe pri 415nm z rumenim filtrom na objektivu, saj daje izboljšane rezultate pri rdeči, bordo rdeči in oranžni podlagi.

Keywords

kriminalistika;kriminalistično preiskovanje;forenzika;forenzične preiskave;forenzična fotografija;krvne sledi;sledi obuval;diplomske naloge;

Data

Language:	Slovenian
Year of publishing:	2015
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FVV - Faculty of Criminal Justice
Publisher:	M. Ličar]
UDC:	343.98(043.2)
COBISS:	3076074
Views:	1767
Downloads:	157
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	MODERN FORENSIC PHOTOGRAPHY : PHOTOGRAPHING BLOOD AND SHOE TRACES
Secondary abstract:	In the theoreticalpart of the thesis the author presents the basis of photography. He defines thebasic parameters for a correct photography exposure, the notion of in-depth focus, he introduces thelenses and devotes part of the thesis to light,to the contrast of the light source and light reflections.Further on he specifies the role of photography in forensics. He introduces the internal instructions for photographing a site of criminal offense in line with theinstructions of the Slovenian Police and defines a situationalsite-specific shot, a relative-proximity shot, and a close-up shot. He focuses on the theory of photography of blood stains. He presents problematic surfaces stained with blood, the usage of chemical reagentsas well as the usage of a flash light for the purpose of such photography. He also touches the theory of photography in relation to photographic capturing of footprints, classifying them into profiled and flat footprints. At the end of the theoretical part of the thesis he tackles digital manipulation of photographs in the sense of digital postproduction. In the empirical part of the thesis he focuses on capturing profiled footprints. With two different imprints of the very same footwearat a different thickness of the walked surface and the depth of the impression of the footwear at the very same structure of the surface he tests how the light’s angle impacts the identification of the photographed footwear’s characteristics. He tests the reaction of light to the footprint from three different positions on the circle around the footprint, at three different angles: a 25-, 50-and a 75 degree angle of the incoming light source. At the end of this part he analyses his findings and gives the so acquired statistical data concerning the pronounceability of control points in correlation to the depth of the footprints, the position and the angle of the light source. 25 and 50 degree angles from which the light is emitted turn out to be the most efficient ones. In the empiric part of his thesis he carries out an experimentof photographing blood stains on cotton fabrics. In his experiment he uses 5 different colours of the same fabric, on which he imprints a blood trace of a footprint, contaminated with pig blood.Then he photographs the footprints at three different types of illumination- LED light, a forensic light source at 415 nm, and a forensic light source at 415 nm with a yellow filter over the camera lens. He analyses his findings in the conclusion of the thesis and gives his opinion.
Secondary keywords:	photography;forensic photography;footwear footprints;profiled footwear imprint;blood traces;forensic light sources;415 nm;
URN:	URN:SI:UM:
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Mariboru, Fak. za varnostne vede, Ljubljana
Pages:	67 str.
ID:	9115838