Understanding Forensic Digital Imaging (eBook)

FRONT COVER 1
UNDERSTANDING FORENSIC DIGITAL IMAGING 4
COPYRIGHT PAGE 5
DEDICATION AND ACKNOWLEDGMENTS 6
TABLE OF CONTENTS 8
FOREWORD 10
INTRODUCTION 14
CHAPTER 1 Introduction to Forensic Use of Digital Imaging 16
WHY TAKE PICTURES? 16
PHOTOGRAPHY AS A SURROGATE 19
SOME HISTORY OF FORENSIC PHOTOGRAPHY 23
FILM VERSUS DIGITAL PHOTOGRAPHY 24
QUESTIONS 26
CHAPTER 2 Dynamic Range 28
ISSUES OF PERCEPTION OF BRIGHTNESS 33
BEER'S LAW 34
DENSITY 35
SENSITOMETRY 35
GENERAL CHARACTERISTIC CURVE DESCRIPTORS 37
CHAPTER 3 Light and Lenses 50
BASICS OF LIGHT 50
THE OBJECT 55
INTRODUCTION TO LENSES 57
LENS PROPERTIES AND MEASUREMENTS 61
LENS FORMULAE 73
CHAPTER 4 Photometry 76
THE SHOWER ANALOGY 77
TIME EFFECTS 84
SPECTRAL COMPONENTS 84
SPECTRAL SENSITIVITY 85
CHAPTER 5 Setting Exposures 88
THE SHOWER ANALOGY REMINDER 88
A THOUGHT EXPERIMENT 88
TWO VIEWS OF EXPOSURE 90
SOME COMPLICATIONS 92
EXPOSURE TIME EFFECTS 93
F/STOPS 94
ADDITIONAL LIGHT 94
PROCESS DIAGRAMS 95
SETTING UP EXPOSURE PREFERENCES 99
QUESTIONS TO CONSIDER 100
CHAPTER 6 Resolution 104
BASICS OF RESOLUTION 104
RESOLUTION CAPABILITY 107
RESOLUTION CAPABILITY OF A CAMERA 110
EVALUATING YOUR CAMERA 114
LIMITATIONS 117
UNDERSAMPLING 118
PRACTICAL OPTIONS 119
NOT ALL DETAILS ARE LINE PAIRS 119
PRINTER CONSIDERATIONS 119
CHAPTER 7 Color Space 122
THE EYES HAVE IT 124
COLOR SPACE 129
THE RGB FAMILY OF COLOR SPACES 130
THE CMY COLOR SPACE 131
THE HSL AND HSV COLOR SPACES 133
CIE/Lab SPACE 136
YCC COLOR SPACE 138
CHAPTER 8 Showing Images 152
FRONT SURFACE REFLECTION 152
BASIC COLORANTS 156
THE MIDDLE GROUND 159
DYNAMIC DISPLAYS 161
COMPUTER-DRIVEN DISPLAYS 161
CHAPTER 9 Key Photographic Techniques 170
PAINTING WITH LIGHT 170
MACRO PHOTOGRAPHY 171
ALTERNATIVE LIGHT SOURCE (ALS) 171
THREE-POINT LIGHTING 172
DIRECT FLASH 172
DIFFUSED FLASH 173
BOUNCE FLASH 173
FILL FLASH 173
OFF-CAMERA FLASH 174
RING LIGHT 174
45°–90° ILLUMINATION 175
PERSPECTIVE GRID 175
INFRARED PHOTOGRAPHY 175
ZONE SYSTEM 176
COMPONENT PANORAMA 177
PUSH PROCESSING 178
BRACKETING 178
LENS TRANSLATION 178
POLARIZED LIGHT 179
CONTRAST FILTERING 179
STEREO PHOTOGRAPHY 180
THREE-DIMENSIONAL SCANNING 180
PHOTOMICROGRAPHY 181
FISH-EYE PHOTOGRAPHY 181
TELEPHOTOGRAPHY 182
EXPOSURE COMPENSATION 182
SUMMARY 182
CHAPTER 10 Image Processing Tools 184
MATHEMATICAL CONCEPTS 186
TONE SCALE ADJUSTMENTS 189
COLOR ADJUSTMENTS 196
IMAGE STRUCTURE ADJUSTMENTS 203
LOCAL VS. GLOBAL ADJUSTMENTS 211
SUMMARY 212
CHAPTER 11 Scanners 222
DRUM SCANNERS 222
FILM SCANNERS 223
SPECULA AND DIFFUSE ILLUMINATION 224
FLATBED SCANNERS 226
SCANNERS vs. DIGITAL CAMERAS 227
SAVING OUTPUTTED IMAGES 228
CHAPTER 12 Digital Circuits 234
BASIC ELECTRICITY 234
ENTERING THE BINARY WORLD 236
DATA REPRESENTATION IN DIGITAL SYSTEMS 237
ANALOG VERSUS DIGITAL SIGNALS 244
SUMMARY 255
CHAPTER 13 File Formats and Compression 256
RASTER FORMAT VERSUS VECTOR FORMAT 256
COMMON COMPRESSION TECHNIQUES 258
COMMON STANDARD IMAGE/GRAPHIC FILE FORMATS 263
CHAPTER 14 Sensor Chips 272
CAPTURING THE LIGHT 272
BAYER ARRAY 275
CCD AND CMOS CHIPS 277
COMPARISONS 278
OTHER APPROACHES 280
A NEW DESIGN 282
CHAPTER 15 Storage and Media 284
REMOVABLE MEDIA 285
CDs AND DVDs 291
NONREMOVABLE MEDIA 298
CHAPTER 16 Computing Images 310
SENSOR CHIP DATA 311
DEMOSAIC 312
NOISE REDUCTION 313
LOGARITHMIC TONE SCALE 314
ENHANCE IMAGE STRUCTURE 315
WHITE BALANCE 316
FORMATTING THE FILE 317
EXPORT THE IMAGE FILE 318
SUMMARY 318
CHAPTER 17 Establishing Quality Requirements 326
PERFORMANCE MEASUREMENTS 326
AN EXAMPLE OF DETERMINING REQUIREMENTS 327
COMPARING FILM AND DIGITAL SYSTEMS 329
RESOLUTION IN DIGITAL CAMERAS 329
RESOLUTION IN FILM SYSTEMS 332
DYNAMIC RANGE 336
SUMMARY 339
CHAPTER 18 SWGIT 342
PRIMARY AND ORIGINAL IMAGES 342
IMAGE FILE AND IMAGE CONTENT 343
THE MYTH OF PERFECTION 344
TYPE I AND TYPE II IMAGES 346
IMAGE PROCESSING TASKS 346
IMAGE ENHANCEMENT 348
STANDARD OPERATING PROCEDURES 348
AUTHENTICATION, INTEGRITY, AND ARCHIVING 349
IMAGE QUALITY 351
VIDEO IMAGING 352
CHAPTER 19 Digital Images and the Investigative Process 354
STANDARD OPERATING PROCEDURES 355
AUTHENTICATION ISSUES 357
VALIDITY AND RELIABILITY OF SCIENCE EMPLOYED 357
PROPER APPLICATION AND INTERPRETATION 358
THE CONCLUSION DRAWN IS PROPER 358
CHAIN OF CUSTODY 359
CHAPTER 20 Getting Digital Images Admitted as Evidence at Trial 362
RULE 104. PRELIMINARY QUESTIONS 364
RULE 403. EXCLUSION OF RELEVANT EVIDENCE ON GROUNDS OF PREJUDICE, CONFUSION, OR WASTE OF TIME 365
RULE 702. TESTIMONY BY EXPERTS 365
DAUBERT AND FRYE 366
RULE 703. BASES OF OPINION TESTIMONY BY EXPERTS 368
RULE 704. OPINION ON ULTIMATE ISSUE 368
RULE 705. DISCLOSURE OF FACTS OR DATA UNDERLYING EXPERT OPINION 369
RULE 901. REQUIREMENT OF AUTHENTICATION OR IDENTIFICATION 370
EVIDENCE 370
REFERENCES AND RESOURCES 381
APPENDIX: Federal Rules of Evidence 2006 384
RULE 104. PRELIMINARY QUESTIONS 384
RULE 401. DEFINITION OF "RELEVANT EVIDENCE" 384
RULE 402. RELEVANT EVIDENCE GENERALLY ADMISSIBLE IRRELEVANT EVIDENCE INADMISSIBLE
RULE 403. EXCLUSION OF RELEVANT EVIDENCE ON GROUNDS OF PREJUDICE, CONFUSION, OR WASTE OF TIME 385
RULE 701. OPINION TESTIMONY BY LAY WITNESSES 385
RULE 702. TESTIMONY BY EXPERTS 385
RULE 703. BASES OF OPINION TESTIMONY BY EXPERTS 385
RULE 704. OPINION ON ULTIMATE ISSUE 386
RULE 705. DISCLOSURE OF FACTS OR DATA UNDERLYING EXPERT OPINION 386
RULE 706. COURT APPOINTED EXPERTS 386
RULE 901. REQUIREMENT OF AUTHENTICATION OR IDENTIFICATION 387
RULE 902. SELF-AUTHENTICATION 388
RULE 903. SUBSCRIBING WITNESS' TESTIMONY UNNECESSARY 391
RULE 1001. DEFINITIONS 391
RULE 1002. REQUIREMENT OF ORIGINAL 391
RULE 1003. ADMISSIBILITY OF DUPLICATES 392
RULE 1007. TESTIMONY OR WRITTEN ADMISSION OF PARTY 392
REFERENCES AND RESOURCES 393
REFERENCE LIST 395
INDEX 398
A 398
B 398
C 398
D 399
E 399
F 399
G 400
H 400
I 400
J 400
K 400
L 400
M 400
N 401
O 401
P 401
Q 402
R 402
S 402
T 402
U 402
V 403
W 403
X 403
Y 403
Z 403