Striation monitor and display system and method

A striation monitor and display system (10) is provided which includes a positional location mechanism (20) for locating a substantially cylindrically contoured object such as a bullet (14). The bullet or object (14) is inserted within a collet mechanism (48) mounted above a cup member (44) containing a compliant matrix (46). A portion of the object (14) is inserted along an axis line (24) of the rotating cup (44). A line scan camera (62) is focused on a section of the object (14) and frame speed is synchronized with the rotation of the rotating cup (44). Synchronization is accomplished by a closed feedback loop between a motor/encoder integral combination (58/60) and a processor system (72) for maintaining synchronization between images photographed by line scan camera (62) and rotational speed of motor (58).

BACKGROUND OF THE INVENTION 
Field of the Invention 
This invention pertains to systems for comparing, monitoring, and 
displaying striations with respect to at least a pair of cylindrically 
formed objects. In particular, this invention is directed to a striation 
display system whereby it may be determined whether striations on one 
cylindrically contoured object match the striations on a second 
cylindrically contoured object. More in particular, this invention relates 
to a striation monitor and display system where a determination may be 
made whether a particular gun has fired two bullets through a comparison 
of the striations formed within each of the bullets. Still further, this 
invention is directed to a striation monitor and display system where the 
object being displayed is rotated at a predetermined rotational speed 
about a vertically extending axis line and is imaged by a line scan camera 
which is focused to a particular section of the object being photographed. 
Additionally, this invention directs itself to a striation monitor and 
display system where the object being imaged is photographed at a 
predetermined image frame speed by a line scan camera which is 
synchronized to the object or bullet rotational speed. Still further, this 
invention directs itself to a striation monitor and display system whereby 
a line scan camera is triggered responsive to a set of pulses including an 
index pulse formed once at each rotation of the object being rotated and a 
predetermined number of encoder pulses which provide for a predetermined 
number of pulses per a singular rotation of the object being photographed. 
Still further, this invention directs itself to a striation monitor and 
display system where the images may be sent to a monitor such as a cathode 
ray tube or to a magnetic disc for storage of the data contained therein. 
Additionally, this invention relates to a striation monitor and display 
system where bullet fragments and cartridge cases may be linearly 
translated in opposition to a rotation in the line of sight of a line scan 
camera with resulting striation data being captured as in the case of the 
rotating cylindrical objects. 
PRIOR ART 
The matching of striations between two objects is known in the prior art. 
It has been possible to determine if an object or bullet has been fired 
from a particular gun by comparing the striations on a first bullet with 
the striations formed within a second bullet which is test fired from the 
gun. However, in the prior art of this procedure, such has required a 
manual microscopic examination of the scratches, or striations made by the 
gun on the bullets as they move through the gun barrel. 
In some prior art systems for comparing the images from bullets, there has 
been used microscopes which involve a human operator to view the 
cylindrical sides of two bullets simultaneously through the same 
eyepieces. In such prior art systems, the bullets are rotated manually in 
an attempt to find a particular rotational angle at which the bullet 
striations match. Generally, striations on bullets fired from different 
guns will not cause a match to be made. 
Even for bullets fired from the same gun, striations will only match at one 
single rotational angle of one bullet with respect to the other. In such 
prior art systems, only a small section of the bullets' surface are in 
focus under the microscopes at any one time which hinders attempts to find 
the correct rotational angle if in fact the bullets were fired from the 
same gun. Such prior art systems and methods are only statistical in 
nature rather than exact due to the fact that even when bullets are fired 
from the same gun and viewed at the correct rotational angles, they are 
not found to match exactly in every respect. 
Prior art systems and methods using manual microscope methods as previously 
described are extremely time consuming and the use of such techniques to 
match or compare large numbers of bullets possibly recovered from crime 
scenes with large numbers of guns found in the possession of potential 
suspects is generally not feasible. 
SUMMARY OF THE INVENTION 
A striation monitor and display system is provided which includes a 
mechanism for positionally locating a substantially cylindrically 
contoured object. A releasable capturing mechanism is used for releasably 
capturing the positionally located object. A rotational mechanism is 
provided for rotating the object inserted within a compliant matrix. The 
object is rotated at a predetermined rotational speed about a vertically 
extending axis line of the object. A mechanism for photographing a portion 
of the object through a plurality of images of the rotating object along a 
vertical direction at a predetermined image frame speed is included within 
the overall system. The photographing image frame speed is synchronized 
with the predetermined object rotational speed and angular orientation 
with the image of the photographed object being displayed or stored. 
Additionally, a removable translating mechanism may be used to convert the 
rotational motion or displacement of the motor into linear translational 
motion of objects past a line scan camera for photographing 
non-cylindrical objects such as bullet fragments and cartridge cases.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIGS. 1-3, there is shown striation monitor and display 
system 10 for displaying and monitoring striations 12 formed within a 
substantially cylindrical contoured object 14 generally having a central 
axis 16 as is shown in FIG. 1. In general, striations 12 of one 
cylindrically contoured object or bullet 14 are to be compared with 
striations of a second bullet fired from the same gun to determine whether 
the striations 12 provide a match between the striations in order to 
determine if the gun used for firing both bullets is the same gun. 
Referring to FIG. 1, a used bullet 14 generally is misshapen at its end 
and contains shards 18 which makes the cylindrically contoured object or 
bullet 14 difficult to mount, as will be seen in following paragraphs. 
Thus, in overall concept, striation monitor and display system 10 is used 
to compare striations 12 between one cylindrically contoured object or 
bullet 14 and a second bullet or cylindrically contoured object 14 to 
determine whether a match of striations 12 can be found. In the event that 
there is a match or comparison equivalency, it can be determined that the 
same gun fired the bullets 14 being compared. Through use of system 10, 
the time in displaying and comparing striations 12 between a pair of 
bullets 14 is optimized and provides increased accuracies in the 
determination of the comparison of the striations 12. 
System 10 includes positional location mechanism 20 shown in FIG. 2 for 
positioning, and capturing mechanism 42 for maintaining cylindrically 
contoured object or bullet 14 in a relatively stationary positional 
location while allowing bullet 14 to be rotated about vertical axes 24 
during the monitoring and display of striations 12. Object or bullet 
placement fixture 22 is used in combination with stationary table 26 and 
is mounted in fixed position thereto. Object or bullet placement fixture 
22 includes fixture lower base member 28 secured to stationary table 26. 
Fixture lower base member 28 may be secured to stationary table 26 through 
bolts, or other threaded securement or even in the alternative may be 
releasably secured thereto, not important to the inventive concept with 
the exception that object or bullet placement fixture 22 be maintained in 
a fixed position with respect to stationary table 26 during particular 
positional placement of bullet or cylindrically contoured object 14 at the 
beginning of the procedure leading to the overall striation comparison. 
Fixture upper base member 30 is vertically displaceable in a reversible 
manner with respect to fixture lower base member 28. As is seen in FIG. 2, 
fixture upper base member 30 may slide on a pair of vertically directed 
fixture rods 34 within bearings 36. Fixture upper base member 30 is biased 
away from fixture lower base member 28 by springs 32 surrounding 
vertically directed fixture rods 34. In this manner, fixture upper base 
member 30 may be moved vertically downward in vertical direction 24 and 
upon insert and capturing of cylindrically contoured object or bullet 14, 
may then be released and displaced vertically away from fixture lower base 
member 28 through spring biasing force. 
Object or bullet placement fixture 22 further includes an optional stop 
mechanism 38 to terminate the downward displacement of fixture upper base 
member 30 with respect to fixture lower base member 28. In this manner a 
particular minimum displacement may be provided between fixture upper base 
member 30 and fixture lower base member 28 during placement of 
cylindrically contoured object or bullet 14. Optional stop mechanism 38 
may be a bolt member which is threadedly secured as shown in FIG. 2, to 
fixture upper base member 30 and provides for a stop bolt lower section 40 
extending below fixture upper base member 30. By threaded rotation of stop 
mechanism or bolt 38, lower bolt section 40 may be elongated or contracted 
with respect to a lower surface of fixture upper base member 30, thereby 
determining a minimum distance between upper and lower base members 30 and 
28. 
Striation monitoring display system 10 further includes capturing mechanism 
42 for securely capturing bullet 14 during the monitoring and display of 
striations 12. Capturing mechanism 42 includes cup member 44 having a 
central axis coincident with vertical axis or vertical direction 24 
passing through the central portion of bullet 14. Cup member 44 has 
contained therein matrix 46 formed of a compliant matrix for insert of 
cylindrically contoured object or bullet 14. In this manner, bullet 14 may 
be inserted into matrix 46 in a secure manner to allow object or bullet 14 
to be rotated during the monitoring procedure. Beeswax has been 
successfully used as the compliant matrix 46 within cup member 44, 
however, other compliant matrices may be used for placement and securement 
of object 14 with the only criteria being that the composition of matrix 
46 is of such a nature as to allow insertion and securement of bullet 14 
therein during rotation about vertical axis 24. 
Object placement fixture 22 of positional location mechanism 20 further 
includes collet 48 mounted to one end of fixture upper base member 30 as 
is shown in FIG. 2. Collet member 48 holds object or bullet 14 in a lower 
section thereof for insert into matrix 46 within cup member 44. Cup member 
44 is rotated about vertical axis line 24 and insert of bullet 14 must be 
substantially coincident with respect to the center line of the rotation 
of cup member 44 in order to eliminate wobble or other eccentrical 
displacements of object 14 when secured within matrix 46. Where any wobble 
or eccentric movement is evidenced as object 14 rotates, such will clearly 
cause displacement of the area being scanned and photographed and thus 
negate any meaningful comparisons between one bullet's striations 12 and 
the striations formed in a reference object or bullet 14. 
Collet member or mechanism 48 is commonly referred to as a non-moving 
collet member which includes a spring-loaded collet section having finger 
holds 50 and an internally located collet spring 52. Bullet or object 14 
may be inserted into collet member or mechanism 48 in a force contact mode 
whereby collet fingers 54 grasp the upper end of object 14. When collet 48 
has been lowered into matrix 46 and the lower end of object 14 has been 
inserted into matrix 46, finger holds 50 are grasped and moved in a 
vertical direction to release object 14 from securement with collet 
mechanism 48. Once this has been completed, bullet or object 14 is secured 
within matrix 46 and may be rotated in unison with cup member 44. 
In order to rotate the secured object 14 at a predetermined rotational 
speed about vertical axis line 24, there is provided cup shaft 56 
extending through an opening in stationary table 26. Cup shaft 56 is 
coupled to motor 58 having attached encoder 60. Motor 58 and encoder 60 
are commercially available from KOLLMORGEN MOTION TECHNOLOGIES GROUP, 
having a place of business in Radford, Va. and the motor/encoder 
combination is from the Platinum Series U9D. The function and operation of 
the encoder 60 which is integral with motor 58 will be described in 
following paragraphs. As will be described, motor/encoder 58/60 are in 
closed loop coupling with the remaining portions of striation monitor and 
display system 10 to provide motor control as to rotational speed of 
object or bullet 14 when mounted in matrix 46 during the overall 
monitoring and display procedure. 
System 10 further includes a mechanism for photographing a plurality of 
images of the rotating object 14 along a vertical direction 24 at a 
predetermined image frame speed. In order to accomplish this photographing 
of a plurality of images, line scan camera 62 with associated camera lens 
64 is aligned with object 14 encased in matrix 46. Alignment of line scan 
camera 62 is accomplished through an adjustment mechanism in vertical 
direction 24, and/or longitudinal direction 66 and/or lateral direction 68 
through any one of a number of mechanisms, one of which being a screw 
table which may have mounted on it the line scan camera 62 and be 
threadedly moved in directions 24, 66 or 68 as is necessary to align lens 
64 with a particular section of object 14. Line scan camera 62 is a 
commercially available line scan camera and is manufactured by DALSA INC. 
of Waterloo, Ontario, Canada, having a Model No. CLC41024N and CLC42048-A. 
Such line scan cameras are well known in the art and provide for the 
photographing of a vertical line image. 
The particular line scan camera 62 being used has associated with it 1024 
or 2048 pixels. Line scan camera 62 being mounted on the adjustable table 
mechanism allows for vertical, lateral and longitudinal displacement as 
has been described. Displacement in vertical direction 24 is important 
since the vertical displacement of the camera allows for capturing images 
in a particular vertical section of object or bullet 14. Longitudinal 
displacement in longitudinal direction 66 may be used for focusing line 
scan camera 62 at a particular section being photographed during rotation. 
Lateral displacement in direction 68 may be used in finding a position 
where light impingement on the outer surfaces of object 14 optimizes the 
images being photographed by line scan camera 62. In fact, displacement in 
lateral direction 68 may be provided out of line with the apex of the 
curvature of the object 14 with respect to line scan camera 62 in order to 
enhance the shadowing and striations 12 being photographed. 
In order to synchronize the rotational speed of object 14 and image frame 
speed of line scan camera 62, synchronizing circuitry is provided in 
combination with processor 72 as is shown in FIG. 4. The object of 
synchronizing circuit 70 is to provide a closed feedback loop to motor and 
encoder combination 58, 60 and maintain a predetermined relation between 
positional points on object 14 and the images being photographed by line 
scan camera 62. Line scan camera 62 only captures one line at a time and 
does not contain memory. The external synchronizing system 70 essentially 
communicates with line scan camera 62 and triggers signals to take each of 
the lines which are going to form the overall image at the proper time. 
In order for synchronization to be accomplished as shown in FIG. 4, encoder 
60 provides index pulse 74 on encoder input line 76 to specify a 
particular position on the rotational surface of bullet 14 as being a zero 
or initial position. Index pulse 74 is generated once per revolution of 
object or bullet 14. The index pulse 74 is used as the initial or zero 
point to start a particular count. Index pulse 74 is input to trigger and 
counter/timer circuit 78 as well as motor controller circuit 80 to be 
further described in following paragraphs. 
Encoder 60 further provides for a series of encoder pulses 82 on encoder 
second input line 84 which are similarly input to trigger and 
counter/timer circuit 78 as well as motor controller 80. Encoder pulses 82 
are provided on second input line 84 in a predetermined number per a 
single rotation of bullet or object 14. In the subject system 10 being 
used 1200 encoder pulses 82 per single rotation are provided however, such 
may be increased, as for example, to 4800 encoder pulses 82 per rotation. 
Both index pulses 74 and encoder pulses 82 are inserted into trigger and 
counter/timer circuit 78 which is an I/O card manufactured by COMPUTER 
BOARDS, INC. of Mansfield, Mass., having a Model No. C10-D1024. The I/O 
card or trigger and counter/timer circuit 78 is commercially available and 
essentially provides for a count of encoder pulses 82 subsequent to the 
input of a particular index pulse 74. Encoder pulses 82 are counted and 
subsequent to counting up a preset number of encoder pulses 82, such 
generates a trigger signal on line 86. The signal passed on trigger and 
counter/timer output line 86 is input to frame grabber 88. Frame grabber 
88 is a commercially available circuit manufactured by BITFLOW INC. of 
Woburn, Mass. and has a Model Designation No. Dataraptor PC1. The trigger 
signal passed from trigger and counter/timer circuit 78 on output line 86 
provides for the actuation of the frame grabber's frame capture mechanism. 
the frame's maximum length may not span the entire circumference of object 
14 and thus multiple frames must be tiled when the entire circumference is 
to be scanned. This is accomplished by computing the number of encoder 
pulses spanned by a current frame and adjusting the offset of a subsequent 
frame by that number of encoder pulses. The process is then iterated until 
the entire circumference has been tiled with successive portions of the 
image. 
Frame grabber 88 upon reception of a signal on line 86 passes a signal on 
frame grabber output line 90 to line scan camera 62 for actuation thereof. 
The line images taken by line scan camera 62 are then passed to frame 
grabber 88 on line 92 as is shown. In essence, and as has been described, 
encoder pulses 82 inserted on line 84 are used to count a predetermined 
distance in rotation of object 14 from the occurrence of an index pulse 74 
to provide successive frames of bullet or object 14. 
In operation, I/O card or trigger and counter/timer circuit 78 is preset by 
a program in memory 94 which is inserted into block 78 on line 96. The 
preset number from memory 94 is used to count encoder pulses 82 which 
provides for a counting of each pulse 82 on line 84 and subsequent to 
counting down in block 78 to a zero position, the desired number of 
encoder pulses 82 provides for the rotation of motor 58 from the zero 
position. When I/O card 78 reaches zero, the signal is triggered on line 
86 serving as the input to frame grabber 88. This signal is used to begin 
capturing a particular frame by line scan camera 62 as has been described. 
Memory 94 also inputs to frame grabber 88 the particular number of lines 
per frame and a line rate which is the number of lines for capturing per 
unit of time, such as per second. Input to frame grabber 88 is made on 
line 98 from memory 94. Once frame grabber 88 has been triggered from line 
86 to begin a frame, pulses are sent over line 90 to line scan camera 62 
and for each pulse sent over line 90, line scan camera 62 will capture the 
vertical line that it has been viewing and output that line back to frame 
grabber 88 on line 92. 
Frame grabber 88 maintains this procedure for assembly of all lines into a 
frame of continuous lines until a maximum number of lines in the frame has 
been reached which is preset in program memory 94. At the time that the 
maximum number of lines has been reached, the frame is terminated. Program 
memory 94 then directs data to memory line 100 and a signal I/O output 
line 102 for insert into CRT 104 or disc 106 or alternatively to some 
other peripheral device for display, monitoring or storage. 
Velocity of motor rotation is read back to motor controller card 80 on line 
108 from memory 94 for maintenance of a particular rotational speed of 
motor 58. Motor controller card 80 is commercially available from 
TECHNOLOGY 80, INC. of Minneapolis, Minn. and has a Model Designation 
TE5638. Motor controller card 80 calculates the current velocity of motor 
58 by signals received on lines 76 and 84 and based upon that input, 
generates a DC control voltage over line 108 to motor 58 to update the 
velocity. In this manner there is provided a closed loop control and the 
motor controller card or circuit 80 maintains a near constant rotational 
velocity of the motor output 58. 
It is to be understood that the fragment of bullet or object 14 being 
imaged by line scan camera 62 may need external light impinging on the 
vertical line of data being captured by line scan camera 62. Light may be 
provided by an external light source (not shown) and through use of fiber 
optic cable with a focusing lens at the output would provide focused light 
on a desired vertical section of the object or bullet 14 being imaged. 
Through use of a fiber optic cable, there would be an optimization of 
space required near the object 14 since the light source would be remote 
from the light impinging on object 14 in the desired sectional area. 
In some embodiments of system 10, a selectable image start function and 
even a motor controller may be coupled directly to line scan camera 62 for 
frame synchronization. Such options and embodiments for initiating a frame 
on the occurrence of a particular event such as a desired rotational 
position of motor 58 are well known in the art and may be employed in 
overall striation monitor and display system 10 as herein described. 
System 10 thus provides a method of displaying and monitoring striations 12 
formed within a generally cylindrically contoured object or bullet 14 and 
initially includes the step of positionally locating object 14. The step 
of positionally locating object 14 includes the step of releasably 
securing object 14 within collet member 48 having a collet axis line 24 
coincident with a rotational axis line of object 14 during the procedure. 
Once object 14 is positionally located, collet 48 is moved in vertical 
direction 24 to provide for capturing the positionally located object 14 
within a releasable medium such as compliant matrix 46 contained within 
cup member 44. Object 14 is inserted within matrix 46 in order that 
striations 12 at the upper or back end portion of object 14 are visible. 
Subsequent to capturing of the positionally located object 14, the object 
14 is rotated about vertically extending axis line 24 at a predetermined 
rotational speed. The step of rotating object 14 includes the step of 
actuating motor 58 having a shaft 56 coupled to cup 44 with the motor 
having a predetermined rotational speed for responsively rotating object 
14 secured within compliant matrix 46. 
The step of rotating object 14 about axis line 24 is followed by the step 
of photographing a plurality of vertical line images of object 14 at a 
predetermined frame speed by line scan camera 62. The photographing of 
vertical section line images includes the step of aligning line scan 
camera 62 with object 14 where line scan camera 62 is focused to a section 
of object 14 being photographed. 
Photographing of the plurality of vertical line images for display on a 
monitor or cathode ray tube 104 or for storage on disc 106 requires the 
step of synchronizing predetermined frame speeds of line scan camera 62 
with the rotational speed of object 14. The step of synchronizing includes 
the step of encoding an index pulse 74 from encoder 60 integral with motor 
58. Additionally, the synchronizing step further includes the encoding of 
a constant predetermined number of encoder pulses 82 for each rotation of 
object 14. The index pulses 74 and encoder pulses 82 are input to a 
trigger and counter/timer circuit 78 for triggering of a signal on line 86 
to frame grabber or frame capture circuit 88 for actuation of line scan 
camera 62 at a predetermined positional location of object 14 as such is 
rotated. 
In some cases, bullets may break into pieces and only fragments of the 
bullet may be recovered after the bullet has impinged a target. In such 
cases, the bullets are somewhat shattered and are non-cylindrical in 
contour. Such object fragments cannot be held in collet 48 and obviously 
cannot be properly rotated in the line of sight of line scan camera 62. In 
order to accommodate non-cylindrically contoured objects 14, an embodiment 
to overall striation monitor and display system 10 is provided as shown in 
FIG. 5. The basic concept is similar to that shown in FIGS. 1-4 however, 
in the embodiment shown in FIG. 5 there is provided linear translation 
mechanism 110 which cooperates with motor 58 and encoder 62 to drive a 
captured object in a linear direction as shown by linear direction arrows 
112. 
As was the case in system 10 shown in FIGS. 1-4, the combined motor 
58/encoder 62 is coupled to processor 72 through lines 76, 84 and 108 for 
providing necessary pulses to processor 72. Output of processor 72 is 
provided on line 102 for immediate display on cathode ray tube 104 or for 
storage on disc 106. 
The difference between the embodiment shown in FIG. 5 and that provided in 
FIGS. 1-4 is generally directed to linear translation mechanism 110. 
Linear translation mechanism 110 includes rack member 114 which is 
slidingly displaced on rack rods 116 in reversible direction 112. Rack 
rods 116 include rack stop members 118 formed at opposing ends of rack 
rods 116 as shown. 
Rack member 114 includes a plurality of rack gear teeth 120 formed on rack 
member 114 which meshingly engage motor gear teeth 122 formed on motor 
gear 124 which is secured to a shaft of motor 58. In this manner, rotative 
actuation of the shaft of motor 58 causes a responsive rotative 
displacement of motor gear 124 and the meshingly engaged motor gear teeth 
122 and rack gear teeth 120 causes linear displacement of rack member 114 
in reversible linear direction 112 as shown. 
Attached to rack member 114 is object holding receptacle 126 which is 
fixedly secured to rack member 114 and responsively is driven in linear 
direction 112 as rack member 114 is displaced. 
Object holding receptacle 126 includes fragment cup or receiving member 128 
within which matrix 46 as previously described may be contained and 
whereby the object fragment may be releasably captured therein. Object 
holding receptacle 126 may also include cartridge receiving member 130 for 
insert of a used cartridge. 
As rack member 114 is displaced by motor 58, object holding receptacle 126 
is linearly translated in direction 112 and passes through the line of 
sight of line scan camera 62. 
In this embodiment shown in FIG. 5, synchronization is obviously directed 
to the synchronization of the linear translation speed of the objects 
being held in fragment cup or receiving member 128 and cartridge receiving 
member 130 with respect to the frame speed of line scan camera 62. The 
trigger and counter/timer 78, frame grabber 88, motor controller 80 and 
memory 94 as shown in FIG. 4 act in substantially the same manner for the 
embodiment of FIG. 5 in overall concept. Object holding receptacle 126 is 
mounted on rack member 114 and holds the objects to be photographed at 
approximately the correct height and correct nominal distance from camera 
62 and associated lens 64. For rack scanning operations, the motion 
profile of motor 58 is a linear translation instead of a continuous 
rotation as was described for FIGS. 1-4. However, accommodation of the 
linear translation is made through motor controller 80 and memory 94 of 
processor 72. 
Although this invention has been described in connection with specific 
forms and embodiments thereof, it will be appreciated that various 
modifications other than those discussed above may be resorted to without 
departing from the spirit or scope of the invention. For example, 
equivalent elements may be substituted for those specifically shown and 
described, certain features may be used independently of other features, 
and in certain cases, particular locations of elements may be reversed or 
interposed, all without departing from the spirit or scope of the 
invention as defined in the appended claims.