A111D3 DflTTSS

NATL INST OF STANDARDS & TECH R.I.C. MCE & TECHNOLOGY:

A1 11 03089752

Wegsteln, Joseph H/The LX39 latent finge QC100 .U57 NO.500-, 36, 1978 C.I NBS-PUB

THE LX39 LATENT

FINGERPRINT MATCHER

)-36

NBS Special Publication 500-36

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act of Congress March 3, 1901. The

Bureau's overall goal is to strengthen and advance the Nation's science and technology and

facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is performed by the National Measurement Laboratory, the National Engineering Laboratory,

and the Institute for Computer Sciences and Technology.

THE NATIONAL MEASUREMENT LABORATORY provides the national system of

physical and chemical and materials measurement; coordinates the system with measurement

systems of other nations and furnishes essential services leading to accurate and uniform

physical and chemical measurement throughout the Nation's scientific community, industry,

and commerce; conducts materials research leading to improved methods of measurement,

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results of its research to the utlimate user. The Laboratory consists of the following centers:

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Engineering and Process Technology^ — Building Technology — Fire Research —

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THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts

research and provides scientific and technical services to aid Federal Agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and

economy in Government operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders, and other directives; carries out this mission by managing the Federal Information Processing Standards Program, developing Federal ADP standards

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'Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, D.C. 20234. Some divisions within the center are located at Boulder, Colorado, 80303.

The National Bureau of Standards was reorganized, effective April 9, 1978.
The LX39 Latent Fingerprint Matclier

w aiANUARDS

AUG 1 6 1978

COMPUTER SCIENCE & TECHNOLOGY: "a^

/ 00

"

J.H. Wegstein and J.F. Rafferty

Institute for Computer Sciences and Technology

National Bureau of Standards

Washington, D.C. 20234

Sponsored by;

Federal Bureau of Investigation

J. Edgar Hoover Building

Washington, DC 20535

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Issued August 1978
Reports on Computer Science and Technology

The National Bureau of Standards has a special responsibility within the Federal

Government for computer science and technology activities. The programs of the NBS Institute for Computer Sciences and Technology are designed to provide ADP

standards, guidelines, and technical advisory services to improve the effectiveness of

computer utilization in the Federal sector, and to perform appropriate research and

development efforts as foundation for such activities and programs. This publication

series will report these NBS efforts to the Federal computer community as well as to interested specialists in the academic and private sectors. Those wishing to receive

notices of publications in this series should complete and return the form at the end

of this publication.

National Bureau of Standards Special Publication 500-36

Nat. Bur. Stand, (U.S.), Spec. Publ. 500-36, 18 pages (Aug. 1978) CODEN: XNBSAV

Library of Congress Catalog Card Number: 78-606167

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1978

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

Stock No. 003-003-01958-5 Price $1.10

(Add 25 percent additional for other than U.S. mailing).
The LX39 Latent Fingerprint Matcher

J.H. Wegstein and J.F. Rafferty

A procedure is described for automatically

determining if a latent scene-of-crime fingerprint matches an inked, rolled file fingerprint.

The procedure uses the x and y coordinates and

the individual directions of the minutiae (ridge

endings and bifurcations). The identity of the

latent print with a print on file is indicated

by a high score resulting from computations based

on differences in angle and coordinate values of

minutiae that are found in going from one of the

fingerprints to the other.

Key words: Automated-fingerprintidentification, pattern

recogni ti on

1. Introduction

An average rolled fingerprint impression exhibits about eighty ridge

endings and forks or bifurcations in its ridge pattern. By comparing the

data representing these minutiae, a computer can determine whether or not

two fingerprint impressions came from the same finger. Figure 1 shows

how the X and y coordinates and the direction 6 are defined for a minutia.

If the areas marked A are ridges then the minutia is a ridge ending, but

if the areas marked B are ridges the pattern is a bifurcation . Since a ridge ending in one print may appear as a bifurcation in another print

from the same finger, no distinction is made between ridge endings and

bifurcations in recording data.

A portion of a fingerprint along with a plot of the corresponding

minutiae are shown in Figure 2. The minutiae data are read automatically

from the rolled impressions on fingerprint cards and in addition, the

reader also produces ridge direction data at equally spaced grid-points

over the entire print. In a fully automated identification system, this

ridge-direction data is utilized in finding the core or "center" of a print as well as the angle through which the print should be rotated.!

This registration information is used to translate and rotate the

minutia data into a standard position. The ridge-direction data in the

neighborhood of each minutia is also used to make slight corrections to

the angle 6 of that minutia. Those registered minutiae within a certain

distance of the center are then sorted into a descending order on y and

this data may then be placed in a file or used to search against minutia

data in a previously established file.

While the high speed M40 and M41 matchers can compare data and

identify rolled fingerprints, a different technique is used for

1
identifying latent fingerprints found at the scene of a crime. Latent

prints often produce only a portion of a fingerprint with correspondingly fewer minutiae than can be read from rolled fingerprints. Some

typical latent fingerprints along with their mates from fingerprint

cards are shown in Figure 3.

Because of their poor quality, latent fingerprint minutiae are read by a fingerprint expert using a semi -automated reader.3 The semiautomati cal ly read minutiae data from latent prints are then compared

with the automatically read data from rolled prints by a special matcher

that is slower and more elaborate than the high-speed rolled print

matchers. It is often impossible to tell which of the ten fingers produced a latent print. Consequently, the search process is further delayed because the latent search print data must be compared with the

data from several of the rolled prints on each file card.

The previously reported M40 matcher can be characterized as a two-stage matcher whose software version requires about 20ms to match

a pair of prints and whose hardwired version matches a pair of prints in

less than a millisecond. On the other hand, the LX39 latent print

matcher described here is a seven stage matcher requiring about 100ms

to match a pair of prints in its software version. This matcher includes a number of parameters that limit its time requirements at a slight risk of missing a match.

2. Selecting Minutiae - Stage I

Figure 4 shows a latent search print and its mating file print

along with a ten-times enlarged plot of its manually-read minutiae —X

superimposed on a portion of the machine-read minutiae —<j from the

inked file print. Note that there are the usual false and missing

minutiae.

In stage I, a box of parameter-determined size is centered on each

of the search minutia and the enclosed file minutiae are tabulated in an array, JT, as shown in Table I. The angle of each of these tabulated

file minutia must not differ from the angle of the corresponding search

minutia by more than a parameter-determined limit (angles are measured

in degrees and distance is measured in units of one-tenth millimeter).

2
Search

Mi n. Fi le Mi nuti ae

I LM LI JTI JT2 JT3 JT4 JT5 JT6

1 3 3 8 12 15 0 0 0

2 6 1 5 6 7 9 11 16

3 2 4 13 14 0 0 0 0

4 4 6 n 17 18 19 0 0

5 6 7 9 11 16 17 18 19

6 4 2 13 26 27 29 0 0

7 4 5 26 27 29 31 0 0

8 6 8 24 26 27 30 32 33

9 0 10 0 0 0 0 0 0

10 6 0 26 27 30 32 33 34

Table 1.

For example, the box around search minutia 2 in Figure 4 encloses file

minutiae 5,6,7,9,11,16 as indicated above. A parameter limits the number

of file minutiae entered in the JT table to the first six found in the

box and ignores 18 and 20o Column LM indicates the number of entries

in each rowo Column LI orders the rows in ascending order according to

column LM. That is, the first value, LI=3, indicates that for 1=3,

LM3=2 is the lowest value in column LM (zero excluded). The next

value, LI = 1 indicates that LM-]=3 is next lowest, and so on.

3. Trial Pair Selections - Stage II

The matcher next seeks pairs of search minutiae that coincide with

pairs of file minutiae. The method of computing the score for a pairfit is shown in Figure 5. DG,DH,DI, and DJ must each be less than an appropriate parameter. Then a large score, MS, indicates that the two

pairs of minutiae fit each other well.

Following the order indicated by column LI in Table 1, search

minutia IA=3 is first placed on file minutia JA=13. The matcher then

tries to place search minutia IB=1, being the next item in column LI, on file minutia JB=8 or 12 or 15. Failing this, it will try to put

minutia IB=4 on JB=11. After a very few of these failures, as determined by a parameter, the matcher will return and place search minutia

IA=3 on file minutia JA=14 followed by placing 18=1 on 8, 12, and 15

where the first fit occurs. The fits are recorded in Table 2. This

procedure continues, but the table length is limited by the trial

terminating parameters.

3
M MIA MJA MIB MJB

1 3 14 1 15

2 3 14 4 19

3 6 26 8 27

4 7 26 10 33

5 7 27 8 30

6 7 27 10 32

7 2 7 5 9

oooo 1

1 nu

9 8 27 10 33

Table 2.

Search minutia MIA=3 sitting on file minutia MJA=14 agrees with search

minutia MIB=1 sitting on file minutia MJB=15 as can be seen in Figure 4.

3 on 14 also would agree with 4 on 19. Table 2 indicates that 8 might

sit on 24, 27, or 30 and this inconsistency is resolved by further

computation.

4. Pair Ordering - Stage III

All of the pairs in Table 2 are arranged in descending order ac- cording to the number of times, NJJ, that a pair occurs. Duplicates

are eliminated. Each pair now appears as NIA-NJA along with its NJJ in

Table 3.

NQ

N

1

NIA NJA NJJ JS M^l 2 3 4 5 6 7 8 9 10 11 12 13 14

• 3 14 2 291 -1 -1 16 -1 19 26 -1 22 -1 -1 -1 -1 -1 -1

2 • 8 27 2 297 -1 -1 13 -1 28 -1 11 19 -1 -1 -1 -1 -1 -1 3 • 10 33 2 374 16 13 -1 -1 23 14 18 18 -1 -1 -1 -1 -1 -1 4 7 27 2 0 -1 -1 -1 -1 -1 -1 -1 -1 15 20 -1 -1 -1 -1

5 • 1 15 290 19 28 23 -1 -1 -1 21 25 0 0 0 0 0 0

6 4 19 229 26 -1 14 -1 -1 -1 -1 16 0 0 0 0 0 0

7 6 26 -1 11 18 -1 21 -1 -1 -1 0 0 0 0 0 0

8 • 7 26 22 19 18 -1 25 16 -1 -1 0 0 0 0 0 0

9 8 30 -1 -1 15 0 0 0 0 -1 -1 0 0 0 0

10 10 32 -1 -1 20 0 0 0 0 -1 -1 0 0 0 0

11 2 7 -1 -1 -1 0 0 0 0 0 0 0 0 0 0

12 5 9 -1 -1 -1 0 0 0 0 0 0 0 0 0 0

13 8 24 -1 -1 -1 0 0 0 0 0 0 0 0 0 0

14 10 30 -1 -1 -1 0 0 0 0 0 0 0 0 0 0

Table 3.

4
The number of entries in Table 3 is limited by parameter to 30 thereby

setting a limit on the computation time required.

In these tables, the correct mating minutiae are marked with dots

to follow their behavior in the course of the matching process. It has

been found in experimental searches that the true mating minutiae tend

to float or rise to the top of Table 3. In actual practice the NJJ

values are usually higher than those in the example shown here.

5. Verification of Pairs - Stage IV

Each of the first six pairs of minutiae in Table 3 that has a NJJ>1 is compared with the rest of the entries in the table using the

procedure described in Figure 5. The resulting MS score is entered as NQ^ ^ and NQ^ ^

in the array shown in Table 3. No computation is

allowed if the NIA's or NJA's are the same. The -I's indicate that the

computation failed to produce a match or that no computation is allowed.

Zeros indicate that no computation was made.

From the NQ array it may be seen that pair 3 on 14 produces an MS score of 16 when tested with pair 10 on 33. A score of 19 occurs with

pair 1 on 15 and so on. It can be seen from Table 3 that the true

mating minutiae tend to produce the most scores along the appropriate

rows of the NQ array.

6. The IS Score

The LX39 matcher computes two scores, IS and RS. Either or preferably both of these scores can be used in a latent print search. The

IS score is obtained by examining each of the first six rows in the NQ

array except for those rows where NJJ^l . Each row is scanned from left

to right. Whenever a positive number is encountered, all of the other

positive numbers in that column are added together. The total of these

sums, JS, is the score for that row. For example, in row one, 16 produces a sum of 13 + 23 + 14 + 18 + 18 = 86; 19 produces a sum of 97;

26 produces 30; and 22 produces 78. Then JS = 86 + 97 + 30 + 78 = 291.

The JS scores for the different rows are shown in Table 3. The highest

of these JS scores, IS = 374 is one of the final scores for the fingerprint match.

7. Relocation of Search Print Center Point - Stage V

The pairs of mating minutiae named by the matrix row that produced

the IS score are used to locate a new center point for the search

minutiae data. In Table 3, the third row names pairs 1, 2, 5, 6, 7, 8.

To develop the formulas for this procedure it must be noted that

prior to being placed in file, the file data were registered so that the core or center point of the finger print was at a standard location

cXjCy. Therefore this point can be located relative to any file
1

minutia F with datum XF,YF,eF. In Figure 6, the point cx,cy can be

located relative to F using angle and distance R where cj) = GF - AF.

If a search minutia S is supposed to lie on the file minutia F then a search print center xc,yc can be located relative to S using

its datum, XS,YS,0S along with R and ^ as shown in Figure 6. Accordingly, each of the mating minutiae pairs named for getting IS is used to

compute a point xc,yc. The resulting xc,yc points are in a small

cluster and the center of this cluster (xx,yy), is taken as the new

| center point for the search minutiae. The angle, N, through which the

search minutiae must be rotated is the mean value of A6 where

AS = 6F - 0S corresponding to each of the mating pairs of minutiae

that were selected earlier.

8. Re-registration of Search Minutiae - Stage VI

The set of all search minutiae which had been centered at the

standard location cx,cy are translated so that the point xx,yy is now at cXjCy and at the same time, the set is rotated through the angle N.

9. The RS Score - Stage VII

Once again considering the search minutiae to be superimposed on

the file minutiae, a small parameter-determined box is centered on each

search minutia. Any file minutia falling in this box with an angle that

differs by only a small amount, determined by a parameter, from the

search minutia angle is paired with the search minutia for determining

the final matching score: RS. In the example used earlier, six mating

pairs of minutiae emerge as shown in Figure 7.

M Search File

1 1 15

2 2 16

3 3 14

4 7 26

5 8 27

6 10 33

Table 4.

Note that one pair, 2 on 16, had not been used in previous stages of the

matching process. The minutiae data of each of these pairs is used to

compute a score, FRS, where:

FRS = constant - | XS - XF| - |YS - YF| - |0S - 0F|

The final score, RS, equals the summation of these FRS scores.

6
10. Testing the Matcher

In order to test the performance of the LX39 matcher, 50 latent

fingerprints including the four shown in Figures 3 and 4 were read

with a semi -automated reader by latent fingerprint experts. These

prints were then searched against a file of fifty fingerprint cards

where each card was known to contain a print corresponding to one of

the latent prints. (For convenience, a search print was given the same identification number as the file card containing its mating print.)

The minutiae data from eight fingers of each card (little fingers

excluded) were read by a fully automatic minutiae reader.^

Because it was originally impossible to tell which of the ten

fingers produced the latent prints, each latent print was compared

with all eight fingerprints from each card in the file. That is, the

LX39 matcher compared each search print with 400 file prints. For each

search print, the highest and second highest RS scores were determined

along with their appropriate card and finger identifications. The

highest and next highest IS scores with their card and finger identifications were also determined. When each search print was being compared

with the eight prints of a given file card, the sum of the eight RS

scores, RST, was also computed and the sum of the IS scores, 1ST, was also computed. For each file search, the highest RST score with its

card identification and the highest 1ST score with its card identification were then determined. The resulting card numbers and scores are tabulated on page 15, In this table, the matcher has produced six file

card numbers for each search print. The search print is considered to

be identified if any of these six numbers agrees with the number of the

search print.

11. Experimental Results

The "hits" are marked by dots on page 15 and the 42 "identified"

latents are marked with an X. Latent print number 12 (finger 9) shown

in Figure 4 failed to achieve any of the highest RS scores, but it did

get the highest IS score (374) as well as the highest 1ST score (488).

Latents 23 and 54 shown in Figure 3 were identified (see page 15).

Latent 20 failed to be identified in spite of the fact that matching

minutiae from its true file mate were at the top of the NQ array during

stage III of that comparison.

In this test there were five cases where the right card was hit by

the wrong finger. In three of these cases the right finger was also

hit by an even higher score as is shown in Table 5.

7
Latent File

Case Finger Type Finger Type Score

1 4-3 U 4-4 U TC— I/IIO nC — TOO lb-l4lo, K5- 1 33

L.? CL- C W 99-1. IaI

o Jo-o U Jo-O U JO J u ?R-4 U

4

~i r\ o I.I "70 O 1.1 DC— TC— ocn Kb- lb/, Ib-obO

70-9 l»f / U ^1 w 7 n - Q Ul / U w PC= Ko— 1 CM

1

Uj

R8-8 IaI RS=?'^1 TS=1'^88

88-8 W 88-6 W RS=168, IS=1458

Table 5

In another experiment with the same prints where the minutiae data were read with a different semi -automated reader, there were seven of

these cases of correct cards hit with wrong fingers. In these cases

the contributing minutiae were examined on the fingerprints and were

indeed found to match each other. This suggests that there is a tendancy for two or more fingers from the same person to have similar

minutiae patterns. It would be interesting to compare minutiae

patterns from the right hand with reflected patterns from the left

hand where the ridge patterns are already known to often be similar.

This experiment also suggests that latent examiners seeking to verify

a hit should compare the latent print with other prints from the same

card when a file print that was "hit" by a search fails to agree with

the latent print.

12. Conclusion

The LX39 fingerprint matcher appears to be capable of making

latent fingerprint identifications in a practical latent search system.

The software version of the matcher requires about 100 ms to compare

a pair of prints, and consequently a large file might require a hardware version of this matcher. The small number of prints tested

here are not sufficient to predict the performance on a large file or

to indicate how many retrieved cards for each search print must be

examined by an expert to confirm identification.

The authors are indebted to R.M, Stock of the FBI for advice

and assistance and to I.R. Futrell and J.E. Ridgely of the FBI for

reading the latent print data. The work was financially supported

by the FBI. The authors also appreciate the assistance of Masatada

5eto of the National Police Bureau of Japan who was a guest worker at

NBS for a year.

8
13. References

1. Wegstein, J.H., Manual and Automated Fingerprint Registration , National Bureau of Standards Technical Note 730, U.S. Government

Printing Office, Washington, D.C, 1972

2. Wegstein, J.H., The M40 Fingerprint Matcher , National Bureau of

Standards Technical Note 878, U.S. Government Printing Office,

Washington, D.C, 1972

3. Moore, R.T., and Park, J.R., "The Graphic Pen, an Economical

Semiautomatic Fingerprint Reader," Proceedings of the 1977

Carnahan Conference on Crime Countermeasures , University of

Kentucky, Lexington, Kentucky, 1977, p. 59-62.

4. Stock, R.M., "Automatic Fingerprint Reading," Proceedings of the

1972 Carnahan Conference on Electronic Crime Countermeasures,

University of Kentucky, Lexington, Kentucky, 1972, p. 16-28.

9
X

Fiqure 1. Definition of Minutia Data

10

Figure 4, (Above), Latent search fingerprint with its mating file

print (x2). (Below), a portion of file minutiae —0 read automatically

with superimposed latent minutiae — read manually on a semi-automated

reader (xlO).

12
DG=|DT-DU|

DH=|DS-DFl

DI=lDU-DA| DJ=|DT-DA|

DZ=Lesser of DI and DJ

DW=Greater of DI and DJ

Score: MS=Constant-DH-DZ-DW

Figure 5. Matching Pairs of Minutiae

CX,Cy DXF = CX - XF

Figure 6. Locating a New Search Minutiae Center

13
c/,cx

Final Minutiae

Pai ri ng

14
Search / St

Card RS

2nd

Card RS

/ St

fdrd l?sr

/ 3t

Card IS

2 nd

Card IS

I St

Card 4.0

1

X 1 I 25D 78 181 M6 706 I* M32M MO 770 1 • M672

X M 78 150 M • 1 33 M6 MB 3 M» 1 M 1 8 78 936 90 188M

X 6 6? I I 8 60 1 1 7 1 2 M77 6* 6M2 22 500 27 930

X 8 8 • 1 6 1 25 1 M3 M6 588 8* 1 350 MO 6 1 0 M6 2 178

X 12 73 1 09 1 5 96 22 3M2 1 2 • 3 7 M 1 5 2 32 12» M88

X I M 1 M • 3 i 8 2M 237 1 M* 893 1 M» 1 528 6M 1 1 M2 1 M» 288M

X «B 63 1 90 90 1 89 62 927 90 I55M 1 5 •! 172 90 3 138

X 17 I 7 • 229 90 22 1 90 1 0M9 21 22MM 7 A \

I O C-7 n\J 21 3298

1 9 1 M 92 M6 87 M3 2 10 1 M 2 10 M 6 \ 6 2 M6 326

20 8 1 3 1 P« 1 1 5 83 M25 15 M36 8 M08 1 5 78M

X 21 2 1 • 2M3 93 1 78 8P 80M 2 1* 297 2 M 2 1 n 7 2 2 !• M550

X 22 M6 I 39 7 1 1 29 M6 57 7 M6 58M 2 2* M 8 M M6 1228

X 23 23 • I 36 83 1 35 90 5M5 2 3* MOO 9 0 2 8 8 90 1000

X 2M 6M 153 2M • 1 36 22 M60 6M 5 10 3 8 M 5 8 88 1108

X 25 25 • M56 1 9 1 99 25* 796 25«762M 1 M 25*7936

27 M3 1 68 83 1 65 M3 780 62 968 7 A <4 15 1608

?R 1 2 239 93 232 93 835 93 I 27M 1 7 9 8 8 M2 2078

X 30 57 20M 1 5 193 1 5 706 30» 1832 flO J Ao 30» 1 96M

32 27 1 92 76 1 76 M3 6 1 M 17 6 10 5 7 5 8 6 83 lOMM

X 3M 1 80 3M • 1 65 25 M80 71 15M6 M 3 ft 7 fi 7 1 2 1 MM

X 38 38 • 208 38 • 1 M3 3 8« 5M8 38« 1 538 o u ft Q M 38# 1 998

X '^o Mij • 303 M2 225 M2 1063 MO'l 950 Q n O J u 22 2M00

X '^2 63 22 1 M2 • 20M M2» 1 1 M7 M2# 1 982 7 » 11 AO oT nu M2»7000

X 's M3 • 31 M 79 1 7M M3» 7M7 M3« 1 870 1 u 1 " ft O ft M3»2800

X '^'^ MM • 1 80 M? 169 M6 523 MM# 1 398 7 M MM»1 770

M6 365 M2 227 62 86 1 M6# I 720 A 7 kODDC, ft M6#2 1 96

I 5 1 1 5 5M • 90 5M» 225 5M» 838 7 R 1 7 n 5M» 93M

55 63 155 1 ? I M8 MO 658 63 1356 1 Q 7 tt 7 63 1562

X57 57 • 1 6M 88 1 M7 M6 638 57* 1530 c5 O Q c; 7 90 20M8

X 60 88 I 79 60 • 156 88 68M 62 682 U. ft A ft 7 88 2M9M

X 62 62 * 1 85 90 1 M6 629 83M 62»2578 V U 11//' 62#M078

X 63 63 • 1 7? 2 3 1 2M 88 35M 63» 1 0M6 83 536 63» 1 0M6

X ^'^ 6M • 1 62 9M 1 M8 27 M78 M2 1336 69 1 1 26 69 18M0

X 69 69 • 2M5 3M 175 3M 586 69» 1060 1 M 75M 69» 1 M2M

X 70 7D • 157 70 • 103 28 350 70» 850 1 2 M 1 M 70* 938

X7I 7 1 • 203 2M 1 88 27 633 7 !• 1 756 1 2 1178 7 1» 2728

X 73 73» 220 28 20M 28 9 1 8 7 3» 1 8 38 28 1 M22 28 3316

X 76 5M 1 28 MO 1 2M 76# 590 90 69M 27 5 1 0 76» 1 1 1 6

X77 85 1 6 1 5M 1 1 6 M6 M57 85 8MM 77« 73M 22 I03M

X78 78 • 1 8 1 38 168 M6 582 1 2 898 6 656 MO 158M

79 85 228 9M 1 8M 27 555 85 16M2 7 1 1110 85 1956

80 57 1 05 5M 99 22 38 3 M3 M 1 6 8 278 M 3 5 1 M X 83 7n 209 62 187 M6 737 70 16 16 83# 1 57M 83« 23M8

X 69 1 2M 93 1 2 1 79 298 38 33M 8 3 1 2 8M» 8M2

X 85 85 • ?3 1 1 2 I 5M 85» 720 85# 1 3 38 MO 798 85»20M2

X ^8 88 • 290 88 • 168 88» 777 88# 1 588 88» 1 M58 88» 3906

X 90 90 » 232 6 197 90« 978 9 0* 1 796 M6 13 10 90«3992

X ''I M 123 9 1 # 122 69 323 9 1# 1 OMO 90 606 9 !• 1 078

X *?3 93* 2M5 M2 220 M6 10 18 93« 1 528 88 1282 93»3030

X 94 9M # 202 93 1 6M 93 800 9M»2962 93 1 M38 93 3680

15
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBS SP 500-36

2. Gov't Accession

No.

3. Recipient's Accession No.

4. TITLE AND SUBTITLE

The LX39 Latent Fingerprint Matcher

5. Publication Date August 1978

6. Performing Organization Code

7. AUTHOR(S)

J.H. Wegstein and J.F. Rafferty

8, Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

1 1. (.contract / Ijrant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Federal Bureau of Investigation

J. Edgar Hoover Bldg.

Washington, D.C. 20535

13. Type of Report & Period Covered

T1 rti'OY*! 1 1 UC 1 1 m111 14. Sponsoring Agency Code FBI

15. SUPPLEMENTARY NOTES

Library of Congress Catalog Card Number 78-606167

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

A procedure is described for automatically determining if a latent scene-of-crime

fingerprint matches an inked, rolled file fingerprint. The procedure uses the x and

y coordinates and the individual directions of the minutiae (ridge endings and

bifurcations). The identity of the latent print with a print on file is indicated

by a high score resulting from computations based on differences in angle and coordinate values of minutiae that are found in going from one of the fingerprints to the

other.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons)

Automated-fingerprint-identification, pattern recognition

18. AVAILABILITY [Xl Unlimited

1 1 For Official Distribution. Do Not Release to NTIS

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1 1 Order From National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

21. NO. OF PAGES

18

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

22. Price $1.10

USCOMM-DC 29042-P74

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