Hoosain M EbrahimDepartment of Medical IllustrationUniversity of Limpopo, Medunsa Campus

PATTERN RECOGNITION OF WEAR, CLASS AND IDENTIFYINGCHARACTERISTICS IN FOOTWEAR

IMPRESSION EVIDENCE

PATTERN RECOGNITION OF WEAR, CLASS AND IDENTIFYINGCHARACTERISTICS IN FOOTWEAR

IMPRESSION EVIDENCE

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IMPRESSION EVIDENCE

Objects or materials which have retained the characteristics of other

objects or materials which have been impressed against them

Footwear impressions can beas having

been made by a specific shoepositively identified

PHOTOGRAPHY OFFOOTWEAR IMPRESSIONS

••

General crime-scene photographsExamination quality photographs

Camera

(Impression)

Light source

-45o

-30o

-15o

OBLIQUE LIGHT PHOTOGRAPH OFTHREE-DIMENSIONAL IMPRESSIONS

Camera

Light is reflected off dust particles and into camera

(Impression)

Light source

OBLIQUE LIGHT PHOTOGRAPH OF TWO-DIMENSIONAL IMPRESSION

Light source3rd position

Light source2nd position

Light source1st position0o

70o

90o

180o190o

270o

290o

LIGHTING

WEAR OF THE SHOE

••

Position of wearDegree of wear

Wear - The erosion of the outsoledue to frictional and abrasive forces that occur between the outsole and the ground

INFLUENCES ON THEWEAR OF SHOE OUTSOLES

•

••

Foot type and functionOccupationHabits

••••

Body typeShoe styleShoe materialsWalking surfaces

Wear pattern

Refers to the wear on the entire shoe or a portion of the shoe

Wear pattern

Anatomical wear pattern

Wear characteristics alone are not accepted as a means of

positive identification

CLASS AND IDENTIFYINGCHARACTERISTICS

•• Pattern recognition•

Knowledge

Assessment

CLASS CHARACTERISTICS••••

SizePattern designContour of imprintShape

COMBINED CLASSCHARACTERISTICS

••

SizeDesign

IDENTIFYINGCHARACTERISTICS

Result when something is randomlyadded to or taken away from a shoe

outsole that either causes or contributesto making that shoe outsole unique

Pattern Recognition Techniquesused as searching criteria

RECOGNITION OFMANUFACTURING

METHODS

Pantograph

Templates

Two hand-engraved moulds using same templatesand pantograph but resulting in different “gross designs”

HAND ENGRAVED MOULD-MAKING

Preliminary classificationFeature classification

Types

Shoe impressions

Partial Complete

Shoe sole collection systems assist in determining the classification of full shoe

impressions

Different pattern designs and possible small differences

within patterns

Pattern designs

Features

RecordedImpressions(filed)

FOOTWEAR IMPRESSIONS

A valuable form of physical evidence

Provide an important link between the criminal and the crime scene

Development of footwear collection

Known criminals Shoe Stores

ESTABLISHMENT OF A DATABASE

•••

Link crime scenesPossible suspectBrand name of shoe

FEATURE CLASSIFICATION••••••

Pattern on edgeToe areaHeel areaCirclesShapes within shapesPatterns surrounding motifs, letters, numbers

VampLogo

Outsole

Tongue Heel collar

Heel back strap

Heel stabilizerHeel quarter

Multi-density midsole

Brand Nameor Logo Area

Border

Arch area

Medial side

Lateral side

PATTERN DESIGNS•

••

••

A hollow circular area inside a circular shapeNumerals inside a circular shapeUnusual shaped studs on the edgeof the soleMotif engraved in the border of the soleETC

FEATURE CLASSIFICATIONCATEGORIES

•••••

•

The edge areaCircular areas surrounded by a valleyCertain featuresPatterns on soleA pattern/shape inside another pattern/shapeThe toe/back of heel area

MAIN GROUPS OFTHE PATTERNS

Digit (first) Pattern01234567

MeshStudWave

Zig-ZagBar

ComplicatedCrepe and plain

Continuous border

PATTERN TYPES IN THE MAIN GROUPS

Digit (second) Shape01

CircularTriangular

Wave or Zig-Zag

Bar patternContinuous border

= Width of line/broken/continuoushigh/low

= width of line/broken/continuous= continuous border of the shoe sole

First Digit ShapePatternSecond Digit

ContinuousBorder

Triangular7 1

Thus 71 means that there are triangular studsin a continuous border

DEFINITIONPattern recognition is the identificationof normal structure and appearance on

an image and those variations of appearances which may indicate a

disordered state

PHYSICAL PATTERNSIN IDENTIFICATION

Identification based on structural features is the recognition

of a physical pattern

PHYSICAL PATTERNSIN IDENTIFICATION

•••

Physical matchingComparison of markingsGeneral shape or form comparison

Database of:•••

Shoeprints at scene of crimeShoes of suspectsShoes on the market

NEURAL NETWORKSIN FORENSIC SCIENCE