Criminalistic Research of Materials and Means of Audio- and Video-Recording

CRIMINALISTIC LABORATORY «LOGOS»

APPLICATION: criminalistic research of materials and means of audio- and video-recording.

COMPONENTS:

– hardware-software unit for the analysis of magnetic records («ПАКАМС-КМ1»);

– the soft-hardware system for the research analysis of speech signals «Phonograph»;

– techniques of criminalistic research of materials and means of audio- and video- recording.

THE DIAGRAM OF INTERACTION OF «ПАКАМС–КМ1» AND TEN HARDWARE-SOFTWARE UNITS «PHONOGRAPH»

1 ПАКАМС–КМ1 The network Phonograph

1 HARDWARE-SOFTWARE UNIT FOR THE ANALYSIS OF MAGNETIC RECORDS («ПАКАМС-КМ1»)

APPLICATION: realisation of criminalistic researches of means and conditions of magnetic recording based of the analysis of magnetic recording data materials.

The unit allows carry out expert criminalistic research of magnetic records with the objective of: – classification of means of magnetic recording; – identification of means of magnetic recording; – diagnostics of means of magnetic recording; – detection of tags of magnetic recording mounting; – restoration of the partially destroyed information of magnetic recording.

BASIC TECHNICAL CHARACTERISTICS

1. Operating aperture of the magneto-optical chips - not larger than 10×13 mm. 2. Relative error at residual magnetiszation measurement - not more than 3% on the top limit of the measurement range. 3. Residual magnetization measurement range - 30−300 Vb/m. 4. Maximum space allowing - not more than 1,0 micron. 5. Absolute error at the linear sizes measurement - not more than 12 microns at the aperture up to 12,7 mm; 1 micron at the aperture up to 0,5 mm. 6. Absolute error at the angular sizes measurement - not more than 0,2 grades. 7. Maximum electric power consumed by the unit - not more than 500 VA. 8. Overall dimensions of the unit - not more than: − 1600 mm at length; − 650 mm at width; − 600 mm at height. 9. Mass of the unit - not more than 140 kg. 10. Meantime to failures - not less than 3000 hours. 11. Operation time in state of maintenance - not less than 8 hours.

2 THE DIAGRAM OF THE UNIT «ПАКАМС–КМ1»

Videomonitor Printer IBM PC Pentium II

Image input adapter Videomonitor Power supply and Sound input adapter commutation CCD camera block Tape-stretching device handling adapter Microscope

Magneto-optikal block

Visualizing device Tape-pressing Inductor Heater mechanism

Tape-stretching device

Reproduction Magnetic tape Headphones channel expenditure counter

Audiocoil Software Videocassette Image processing. Compact-cassette Linear and angular sizes measurement. Support of input of videosignals and sound. Tape-stretching device handling. Microcassette Evaluation of reliability and registration of expertise. The database of standard metrics of equipment of magnetic record. Changeable items

3 COMPONENTS OF THE UNIT «ПАКАМС–КМ1»

Рiс.1. General view of the unit «ПАКАМС–КМ1»

1. A magneto-optical block (МОB) - is intended to transform of magnetic records into visible image with the help of Bi- contained ferro-granat crystal.

Fig.2. General view of a magneto-optical block

Technical characteristics: − the operating aperture of the magneto-optical crystals - not larger than 10 ×13 mm; − magneto-optical crystals space allowing - not more than 1,0 micron; − the MOB smooth scanning is perpendicular to the magnetic tape driving within the limits ±7 mm; − scanning step – 24 ±5 microns (on circular scale); − manual and automatic pressing of the magnetic tape to the magneto-optical crystals; − the number of changeable cassettes: а) magneto-optical crystals cassette - 5 pieces; 4 б) cassette for pressing - 2 pieces; − the characteristics of the MOB operating fields:

Fig. 3. General view of the magneto-optical crystals The size of the magneto-optical crystals Objective expansion operating field on the display (in micron) 20 Х 550 × 410 10 Х 810 × 1126 3,2 Х 3360 × 2550 2. The tape-stretching device (TSD) - is intended for multifunctional movement of a magnetic tape.

Fig. 4. General view of the microscope, MOB, CCD camera and TSD with the changeable item

5 Basic technical characteristics: − standard sizes of the magnetic tapes: 12,7 mm; 6,3 mm; 3,8 mm; − types of winding devices of phonogram carriers used: compact cassettes, microcassettes, audiocoil according to IEC 94-7 (1986) and ГОСТ 24863-87; − the used type of devices of winding of media videophonograme: the cassette VHS according to IEC 774 (1983) and ГОСТ 28356-90;

Fig. 5. Changeable items for various types of magnetic carriers - basic TSD states are supported by a program and are set by the TSD handling adapter from the PC keyboard; - the following number of speeds is realized (in cm/sec): 19,05; 9,53; 4,76; 2,38; 1,19. The tuning of the speed nominal is provided within the limits of ±5% with a discrepancy of 1%; - step movement of the magnetic tape with the step size about 2,5 mm. Period between steps - not more than 2,5 sec.; - the speed of accelerated winding of the magnetic tape - not less than 5 m/sec; - in case of breakaway or jamming of the magnetic tape TSD stops automatically and the TSD is blocked until the stopping reason are eliminated; - automatic movement of the magnetic tape to the distance equal to the length of the segment between the magnetic head and magneto-optical crystal. Time of improvement - not more than 25 sec.; - automatic movement of the magnetic tape up to a given mark in a mode of accelerated wind. The error of repeated positioning of the mark - not more than 2 m, at carrier’s length - 500 m; - superposed magnetization of the magneto-optical crystal by the inductor’s magnetic field with the normal induction component Нn with the accuracy ±1 %; - the indicator of the magnetic tape expenditure counter shows the current value of the magnetic tape expenditure in centimetres and the reproduction time in minutes; - the marks are installed according to current observations of the counter of the magnetic tape expenditure. The TSD handling program allows to make up to 100 marks simultaneously. 6 3. Power supply and commutations block. 4. Commutator of peripherals КВУ-54. Functions: - commutation of 16 sound linear stereo inputs and outputs. Any input can be connected to any output; - signal source commutation for listening on a head telephone. Any of 16 linear stereoinput can be chosen for listening on any telephone of headphones irrespective of other telephone, which can also be connected to any of 16 stereoinputs (dichotonic mode). The stereoinput being chosen, the mode for each telephone can be defined: the left channel, right channel of the selected stereoinput or mоnо; - conversion of a stereoinput into a monoinput. Switching between a stereooutput and monooutput for each of 16 sound outputs is possible; - commutation of one out of four videoinput with one videooutput; - connecting/disconnecting of 16 external customers to/ from the voltage 220В; - all operational modes of the commutator are handled from a personal computer on a consequent link channel of the RS-232 standard.

Fig. 6. General view of the power Fig. 7. General view of the commutator КВУ–54 supply and commutation block 5. The amplifiers of reproduction channels - are intended for input of a signal from two channels of the magnetic induction head or from any 6 channels 21-channel magnetic resistant head according to the recording format. 6. Analog-to-digitial beep converter. 7. Commutator. 8. Magnetic tape expenditure counter. 9. Image input adapter. 10. Tape-stretching device handling adapter. 11. Microscope «JENAPOL» 30-G0060a. 12. CCD camera «MINTRON» MTV-1802 CB. 13. Laser printer HP Laser Jet 6P. 14. Headphones AKG K-100.

7 15. Software «CADR» (version 1.6) with the extension unit «EXPERT». The universal software processing of the images «CADR» is intended for processing gray scale images with formats from 16×16 up to 512×256 points with measuring accuracy of 8 bits on a point (256 levels of brightness) on computers of the IBM PC/AТ class and allows to realize:

- the output of black-and-white or pseudo-colours (in rainbow) images and also in tabular form of three-dimensional contours; - the output of the graphs of any cuts, level allocation histograms; - editing of frames with the help of an inbuilt graphics editor; - filtering both with the help of created НЧ, ВЧ, and median filters and with the help of filters programmed by the user with the help of the inbuilt graphical editor of filters; - correction of nonuniformity of light exposure; - processing by functions of levels conversion assigned by the user with the help of the in-built graphics editor or with a table; - threshold processing, amplification, negative, noise production, mirror reflection, binary operation, etc.; - operations over two frames or frame and constant: summation, subtraction, calculation of arithmetic average, etc.; - Fourier processing: calculation of spectrums in absolute and logarithmic scales, calculation of the autocorrelated function and cross correlations of two frames; - storage of images on a disk, both as a bit image and in various formats: PCX, BMP, GIF, IMA, etc., at reading the format is recognized automatically; - printing of images and other information.

The extension unit «EXPERT» functions in the following five modes: - TSD handling and images input mode; - image seaming mode; - mode of definition of distances and angles which do not exceed the size of a frame; - mode of definition of distances and angles exceeding the size of a frame; - sound input mode. With the help of menu the user can select a way of the output and colouring of images, graphs, contours and tables, modes of input, processing and printing. Due to the multiwindows interface it is possible to output simultaneously a great number of various information on the screen. In the process of program operation the context-dependent help is available. The program is completely written on the assembler what causes its high speed.

16. Technical description and maintenance instruction.

8 HARDWARE-SOFTWARE COMPLEX FOR THE ANALYSIS OF SPEECH SIGNALS «PHONOGRAPH»

APPLICATION: criminalistic researches of speech signals.

Technical characteristics:

1. Format of sound files - WAV. 2. The monomode of a format Windоws PCM of 16 bits for reproduction with any sampling rate is accepted (limitations accepted are determined by a sound card installed in PC). 3. For record it is possible to select sampling rate from a number: 8, 11, 16, 22, and 44 кHz. 4. Amount of marks- 512, the number of levels of marks - 4, text part - the mark identifier should not exceed 16 tags. 5. Modes of repetitions: - length of a fragment is determined by duration of a site, selected on phonogram; - the amount of repetitions is installed manually (2-5 times), at cycling of a fragment the amount of repetitions is installed - 99. 6. Range of reproduction speed change - ±50 % with the step 5 % from nominal, noted in header line of the sound file. 7. Amount of points at calculation the Fourier of conversion - 1024. If the fragment is shorter than 1024 counting, addition of a fragment by zero counting is executed. 8. Amount of filter bars - 128. The level in a bar is regulated with a discrepancy 6 dB. 9. Amount of points for a variation of the function of a non-linear amplification - 2. 10. Accuracy of time interval measurement - 0,01 seconds. 11. Accuracy of amplitude measurement: by the scale of oscillogram - 1 dB, by the scale of spectrum - 0,1 dB. 12. Accuracy of frequency definition Fd /1024 (by the scale of spectrum) or Fd/256 (on shears of spectrogram), where Fd is the sampling rate. 13. Accuracy of definition of main tone frequency period - 1/ Fd. 14. Dynamic range of the Fourier conversion - 80 dB. 15. Minimum duration of a speech fragment for execution of the integrated analysis by the «Dialect» technique - 11 sec. of pure, in speech without pauses. 16. Minimum duration of a speech fragment for execution of the triads on the «Dialect» technique - 8-10 triads (triad is a combination of sounds: consonant – vowel – consonant).

9 THE DIAGRAM OF THE UNIT «PHONOGRAPH»

Videomonitor Printer

Personal computer

Sound card

Headphones Balancing unit Commutator of peripherals

Compact-cassette Software recorder

Microcassette Input (output) of a phonogram in (out of) PC. recorder Realization of functions of the digital tape unit. Filtering and companding of a phonogram in real time. The classical analysis of the characteristics of speech signals Coil tape recorder The automated identification analysis of a voice on a "Dialect" technique with obtaining of probable solution about coincidence of voices "one’s own" or noncoincidence - "somebody else's". Videorecorder Installation of number of a copy of a phonogram by the frequency of 50 Hz. Automatic definition of telephone number on voice- Videomonitor frequency sendings, fixed on a phonogram

Amplifier

Acoustic system

10 COMPONENTS OF THE UNIT «PHONOGRAPH»

Fig. 8. General view of the unit «Phonograph»

1. The personal computer (type Pentium II). 2. Sound card of the type Gravis Ultra Sound P&P. 3. Balancing unit - is intended for the coordination of an input of a sound card with an output of reproduction devices.

Fig. 9. Exterior view of the device of the coordination

4. Software "Phonograph" - is intended for: − input-output of a phonogram in out of) the personal computer; − definition of a content of conversations with the simultaneous implementation of functions of the digital tape recorder and operation in any text editor in the Windows environment; − filtering and compandering of phonograms in real time;

11 − realisation of the phonogram analysis on fitness for identification researches; − measurements of temporary, amplitude and spectral characteristics of voice and speech of a person, as well as other signals fixed on phonogram; − executions of a statistical analysis; − the automated Identification analysis by the «Dialect» technique and obtaining of an evaluation of comparability of voices of various speakers; − determination of the number of the phonogram copy on frequency of 50 Hz; − definitions of possible mounting phonogram on spectrums of noise of a pause. The reproduction is carried out in sequential and cyclic modes, that increase the quality of perception and synchronic documenting. For compensation of phonogram distоrtions, connected with changes of reproduction speed and improving of articulation the smooth change of speed of reproduction is ensured. The lowering of a level of noise and rise of articulation is ensured by the possibility of filtering and non-linear amplification of reproduced phonograms. The complex allows to realize the spectral analysis of fragments of the phonogram: calculation of an average amplitude spectrum, average enveloping of an amplitude spectrum, average narrow-band amplitude spectrum. The identification researches on the «Dialect» technique will be carried out by integrated tags (501 tags: spectral, correlation and voice-frequency statistical tags) and by the tags of a research of triads of sounds (144 tags: statistical researches of duration of vowels and consonants, frequency of main tone and frequency of formants). 5. Headphones. 6. Commutator of peripherals КВУ-54 (see page 5). 7. Tape unit bobbin. 8. Compact-cassete tape recorder. 9. Microcassete tape recorder. 10. Videotape recorder with the screen monitor. 11. Amplifier with the acoustic system. 12. Technical description and maintenance instruction.

12 STRUCTURE OF RESEARCH TECHNIQUES

Dictionary Definition of a content of Automated analysis of terms conversations. Filtering and ("Dialect" technique, lowering of noise level 771 tags) phonogram. Scientific - theoretical fundamentals Evaluation phonogram on Classical analysis of research fitness for realization of identification of researches of a voice and speech. Instrumental analysis Techniques of research Identification and unidentification researches Linguistic analysis Technical of voice and speech of speech means ( 136 tags)

Identification researches of 245 sources General equipment of magnetic of literature description of speech recording ( 66 tags) Psycho-linguistic Appendix characteristics (help Diagnostic researches of materials) equipment of magnetic recording Prosodic ( 57 tags) characteristic

Search of mounting traces Phonetic ( 41 tags) characteristics

Classificational research of Lexical equipment of magnetic characteristics recording ( 9 tags) Morphological characteristics

Syntactical characteristics

Stylistic characteristics

Analysis at the microtext level

13 STRUCTURE, PURPOSE AND EXAMPLES OF PRACTICAL APPLICATION OF THE RESEARCH TECHNIQUES

1. Definition of the content of conversations, filtering and lowering of noise level of the phonograms - definition with the maximal-possible accuracy of a content of talks fixed on a phonogram, and also rise an articulation of speech both lowering of noise and interference level.

Fig. 10. Definition of content of a conversation with the help of programs «Phonograph» and «Microsoft Word»

Fig. 11. Filtering phonogram with use of a filter 14 Fig. 12. Non-linear amplification of phonograms with the use of a compander

2. Evaluation of phonograms on fitness for realisation of Identification researches of voice and speech - definition of parameters of phonograms and speech permitting to evaluate fitness researched material, for realisation of Identification researches of a speech signal.

Fig. 13. Measurement of the ratio a signal/ noise in frequency bands

15 Fig. 14. Measurement of an integrated evaluation of the ratio signal/ noise

3. Identification and unidentification researches of voice and speech. Identification research of voice and speech of a person – definition of an individual identity of the person according to his voice and speech fixed on an experimental sample and researched phonogram.

Unidentification research of voice and speech of a person - research of text and personal characteristics of voice and speech fixed on the researched phonogram.

Instrumental analysis by classical methods of researches. Prosodic, spectral, amplitude, temporary and other characteristics of speech signals refer to classical methods of research.

16 Fig. 15. Automated search of comparable sounds

Fig. 16. Automatic segmentation of voice-frequency sites of speech

17 Fig. 17. Research of an average spectrum and spectrogram of speech

Fig. 18. Calculation of values of frequency of basic tone

18 Fig. 19. Calculation of statistics on frequency of basic tone

Fig. 20. Formant analysis of speech

19 Fig. 21. Statistical calculation of values of formants

The automated instrumental analysis by the "Dialect" technique

Fig. 22. Acceptance of the probable solution about coincidence of voices "one’s own" or incongruity - "somebody else's" accordingly the results of comparison of the analysis of speech implementations with the duration 10-100 sec.

20 Fig. 23. Automated creation of a data bank of comparable triads of sounds (consonant- vowel- consonant)

Fig. 24. Acceptance of probable solution about coincidence of voices "one’s own" or incongruity - "somebody else's" by the results of a research of triads of sounds 4. The identification researches of equipment of a magnetic record - definition of an individual identity of a recording means by comparing of identifying objects reflections, as which appear researched phonogram and phonogram - experimental sample.

21 Fig. 25. Identification of the tape recorder by the method of measurement of geometrical sizes of a format of stereophonic record of phonogram and statistical comparison to standard values

Fig. 26. Identification of the videotape recorder by a method of measurement of the geometrical sizes of a format VHS of the videorecord and statistical comparison to standard values

Fig. 27. Identification of the videotape recorder by the method of a research of mutual layouts of magnetic tracks in a control channel 22 5. Diagnostic researches of an equipment of magnetic record - definition of availability index of product of an equipment and recording carrier, and also evaluation of record realisation conditions on tags of the researched object.

Fig. 28. A non-standart angle of installation of the head of record in relation to the edge of magnetic tape

Fig. 29. Non-contact of a magnetic tape to the head of record

Fig. 30. Non-standart installation of the head of Fig. 31. Hidden (non format) record: record. Restoring of the previous A, C – format tracks; recording with the use of multichannel B – non format track magneto-resistant head: 1,2 – residuals of the previous records; 3 – new record

23 6. Search of mounting tags - definition of availability (absence) of editions (synthesis), copying of the source phonogram on the tags of researched objects (carrier with recorded on it phonogram and recording means).

Search of traces of phonograms mounting, executed by stopping of the tape recorder (Fig. 32-37).

Fig. 32. Magnetic impulse remained from Fig. 33. Magnetic impulse remained from switching the recording head on switching the recording head off

Fig. 34. Magnetic impulse remained from Fig. 35. Magnetic impulse remained from switching the erasing head off Switching the erasing head off (when (in case of the inductive head) the head is a permanent magnet)

Fig. 36. Magnetic impulses remained from Fig. 37. Magnetic impulses remained from switching the recording head on-off switching the recording head in "stop" mode on-off "pause" mode

24 Search of traces of videotape recordings mounting of VHS format, executed by stopping of the videotape recorder (Fig. 38-43).

Fig. 38. Non-recurring synchro-impulses Fig. 39. The same enlarged of the control track

Fig. 40. Overlap of the sound tracks: Fig. 41. The same enlarged 1 - old record; 2 - new record

Fig. 42. Magnetic impulse remained from Fig.43. Video track of a synchronization switching the erasing head off breakdown: 1 - old record; 2 - new record

Fig. 44. Definition of the original/ copy by the method of the research of a spectral component 50 Hz 25 7. Classificational researches of magnetic recording equipment - definition of group belonging of the recording equipment and carrier by the tags of the researched object (carrier with the phonogram recorded on it). One of examples of classificational research of the equipment of magnetic record is the definition of the class of the equipment of record by the type of the used erasing head (see Fig. 34, 35).

Additional information on operation of hardware-software complexes can be received by the addresses:

Відділ досліджень матеріалів та засобів звуко– і відеозапису Державний науково–дослідний експертно–криміналістичний центр МВС України 252024, м. Київ, вул. Богомольця, 10 Тел./факс.: 510–89–94

Радіотехнічний факультет Національного технічного університету України, кафедра радіотехнічних приладів і систем, Галузева науково-дослідна лабораторія методів і засобів спеціального призначення 252056, м. Київ, пр-т Перемоги, 37 (2103) Тел./факс.: 274-89-84, E-mail Leviy @ lmmfr.kiev.ua

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Криминалистический комплекс "ЛОГОС" находится только на вооружении Министерства Внутренних Дел Украины.