Sample Sample Pattern Area training Module


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Sample on-line training from FBIS

Sample Sample Pattern Area training Module

  1. 1. fingerprint Capture and Pattern Area Determination<br />Small sample of Module 3<br /> Forensic Biometric Identification Solutions LLC.<br />
  2. 2. Common fingerprint termsused in this training program<br /><ul><li>Bifurcation, is the forking or dividing of one ridge into two or more ridges.
  3. 3. Divergence, is the spreading apart of two ridges that have been running parallel or nearly parallel.
  4. 4. Fingerprint patterns fall into 3 major pattern groups loops, arches and whorls. Each grouping has the same general characteristics.
  5. 5. Patternareais the part of the finger impression used in the interpretation and classification of a finger.
  6. 6. Type lines may be defined as the two innermost ridges that surround or tend to surround the pattern area.
  7. 7. Focal points are found within most pattern area’s usually a delta and core.
  8. 8. The delta first obstruction at the point of divergence of the type lines in front of or nearest the center of the divergence.
  9. 9. Core approximate center of the patter area.
  10. 10. Tracings are used to break down whorl patterns into smaller sub-groupings.
  11. 11. Automated fingerprint identifications systems( AFIS) are fingerprint search systems designed to search, store and retrieve fingerprint cards.
  12. 12. Line of Flow imaginary linebetween the delta and core in loop and whorl patterns. Line of flow is used to determine sufficient recurve in patterns.
  13. 13. horizontal plane is the ridge directly below an up thrusting or angular ridge in a tented arch pattern, the baseline ridge enters the pattern may rise slightly and exits on the opposite side from which it entered.</li></li></ul><li>Permanent & Unique to an Individual<br />Fingerprints have been used as a means of identifications for more than 2000 years. In <br />1890 the first textbook published on fingerprints by Sir Francis Galton argued no two <br />fingerprints are the same, and that fingerprints remain unchanged over time. Today, the <br />American Institute of Applied Science states “ The basis of fingerprint identification is the <br />premise that the configurations formed by the raised ridges of the palmar surface of the <br />hands are unique and do not undergo any natural changes, except growth, from fetal life <br />until decomposition”. The permanence and uniqueness of fingerprint ridge detail is an <br />accepted fact in the scientific community as often demonstrated in terminology used by <br />scientists; a chemist for example will often use the term &quot;fingerprint region&quot; to describe an <br />area of a chemical that can be used to identify it. In addition to the scientific principles of <br />the permanence and uniqueness of fingerprint ridge detail, it was found that based on the <br />variations in the patterns formed by the ridges, the fingerprints could be grouped into a small <br />number of pattern types. This ability to classify fingerprint pattern type has allowed <br />fingerprints to replace previous Identification systems , today fingerprints account for more <br />positive Identifications of individuals worldwide daily, than any other human identification <br />procedure. <br />
  14. 14. Utilizing fingerprints<br />Classification systems were developed to utilize the distinctive ridges that appear on the <br />inside of the end joints of the fingers and thumbs. Fingerprints fall into three major pattern <br />Groupings (loop, arch, whorl). Each pattern group has the same general characteristics or <br />family resemblance. The three major pattern types may be further divided into subgroups by <br />means of smaller differences existing between the patterns, in the same major group. The <br />arch group includes the plain arch and the tented arch the loop group includes the radial and <br />ulnar loops. The whorl group includes four types of whorl, the plain whorl, central pocket <br />Loop whorl , double loop whorl, and accidental whorl. This ability to categorize each finger <br />allowed agencies to store the fingerprint cards in small easy to mange bins of fingerprint cards <br />allowing quick and accurate access to the fingerprint database. The Henry classification <br />utilized both the major pattern grouping and the pattern subgroups in it’s classification <br />formula which allowed agencies to store, search and retrieve fingerprint records quickly and <br />accurately. The systems could be used by small agencies with hundreds of fingerprint cards <br />as well as large state agencies housing millions of fingerprint records. In the early 90’s <br />automated fingerprint identification system began to replace the manual fingerprint systems. <br />The automated systems allowed classification rules to be relaxed utilizing computer <br />technology to store, search and retrieve fingerprint records based more on minutiae detail <br />than pattern type. <br />
  15. 15. Fingerprint Patterns<br />All fingerprint images can be categorized into one of these three(3) main pattern groupings. These pattern groupings are defined by their unique general characteristics. The patterns groupings can be further divided into sub-groups by means of smaller differences existing between the patterns in the same pattern group.<br />In this course we will look at the main pattern grouping as well as the sub groups associated with them. There are a number of rules and definitions used in determining pattern and pattern area, which we will go over in the next few slides. <br />Loops<br />Arches<br />Whorls<br />Simple way to remember the major pattern groups LAW<br />
  16. 16. Determining Major Pattern Grouping<br />In order to determine the pattern grouping for a fingerprint, <br />there are a number of guidelines followed in all classification <br />systems, these guidelines insure uniformity in fingerprint <br />pattern determination. The fingerprint pattern today is used as <br />a filter in automated fingerprint systems and a correct pattern <br />can impact the results of a latent or ten print search, The 1st. <br />area of interest in determining pattern type is the pattern area. <br />Pattern area is where you will find all the information required <br />to accurately determine the correct fingerprint pattern. The <br />pattern area contains the focal points used in determining <br />the fingerprint pattern. The pattern area is present in all <br />patterns, but in most arch patterns it is impossible to define. <br />The fingerprint pattern area in loops, whorls and some arch <br />patterns will contain the delta(s), core and ridges used in the <br />pattern determination process.<br />Automated Fingerprint <br />Identification Systems <br />when searching latent <br />Images normally are <br />60-70 % accurate. Using<br />pattern to limit the number<br />of suspects increases the<br />likelihood of identifying a<br />latent with a suspect in the <br />database.<br />
  17. 17. The Pattern Area is defined by the Typelines.<br />The typelines are the two (2) innermost ridges that run parallel, diverge and surround or tend to surround an area of ridge detail. The enclosed area of ridge detail is defined as the pattern area.<br />Red lines highlight type lines that define the pattern area. Pattern area is that part of a loop or whorl in which appear the core(s), delta(s), and ridge(s) with which we are concerned in fingerprint pattern determination and classification.<br />
  18. 18. Type lines are not always continuous ridges<br />Type lines are not may not always two <br />continuous ridges, in fact most typelines <br />are not continuous ridges. The causes of the <br />breaks could be natural, damage to the <br />finger or just a poorly captured fingerprint <br />images. Most typelines will have slight ridge <br />breaks, bifurcating ridges or the ridge will <br />end abruptly. When there is a definite break <br />in a type line, the ridge immediately outside <br />of the break is considered the continuation <br />of the ridge. If the type line bifurcates, take <br />the ridge that tends toward the middle of the <br />pattern area as the continuation of the <br />type line.<br />
  19. 19. Determining Pattern Area<br />Small break due to the way<br /> Prints were captured ignore<br />The break<br />The small breaks in the ridge due to poor <br />image quality, worn ridges etc. are not <br />considered definite ridge endings and you <br />continue following the ridge after the slight <br />break. As we stated earlier the pattern area <br />contains the cores, deltas, and ridges which <br />are required for accurate fingerprint patter <br />determination.<br />The break in this type line is caused by a <br />temporary scar and is not considered a break<br />In the type line.<br />
  20. 20. Angled Ridges <br />Angled ridges cannot be used as type lines. The angled ridge is formed by two(2) ridges, one abutting up against the other ridge. The definition for a type line the two (2) innermost ridges that run parallel, diverge and surround or tend to surround an area of ridge detail. Since an angle is formed by formed by two separate and distinct ridges it does not meet the definition for a type line.. <br />Type lines are these 2 innermost<br />Ridges that run parallel and diverge<br />2 ridges meeting forming an angle<br />Cannot be used as a type line.<br />
  21. 21. Type lines Bifurcating Ridges<br />Bifurcation 1 ridge<br />into 2 ridges<br />In the example to the right we see B a bifurcation<br />one(1) ridge splitting into two (2) ridges. The <br />bifurcation does not run parallel to the type line <br />A, so it can’t be used as a type line. We move <br />outward to ridge which does run parallel to A, this <br />meets the criteria for a type line and is in fact the <br />Type line in this pattern. <br />C<br />B<br />A<br />Type lines, ridges run <br />Parallel then diverge<br />
  22. 22. Type lines<br />The rule for a type line is it must run parallel, a type lines can be very short. Care must be exercised when locating the type line. <br />Two forks of a bifurcation cannot be used as <br />type lines. The exception to this rule is when the <br />forks run parallel after bifurcating and then <br />diverge. In such a case the two forks become <br />the two innermost ridges required by the <br />definition. <br />
  23. 23. Now That You have determined Pattern Area<br />Once the pattern area has been determined, <br />you can locate theca points of that pattern:<br />Delta<br />Core<br />Ridge detail<br />First we’ll look at defining and determining <br />the delta of the fingerprint pattern. <br />
  24. 24. The delta is the first ridge or part of a ridge at or in front of and nearest the<br /> center of the point of divergence of the fingerprint type lines.<br />Area’s where the delta formations are usually found. The first obstruction of any <br />nature at the point of divergence of the type lines in front of or nearest the center of<br /> the divergence. <br />
  25. 25. Delta<br />The delta may be:<br />● A bifurcation<br />● An abrupt ending ridge<br />● A dot<br />● A short ridge<br />● A meeting of two ridges<br />● A point on the first recurving ridge located nearest to the center and in front of the divergence of the type lines.<br />
  26. 26. Core<br />Cores, as the name implies, the core is usually the <br />approximate center of the pattern area. In loop <br />patterns the rule used to determine the core is the <br />sufficient recurve rule. Simply stated there has to <br />be a recurving ridge with a sufficient recurve. A <br />sufficient recurving ridge in a looping pattern is one <br />free of appendages that abut on the outside of the <br />ridge at 90 degree angle between the shoulders of <br />the looping ridge. Since a majority of the patterns <br />are looping ridge types of patterns we will look at <br />determining the core in these patterns 1st. <br />
  27. 27. Sufficient Recurve<br />In order to determine core placement in a <br />looping fingerprint pattern, you first need <br />To determine if the pattern has a sufficient <br />recurve. Sufficient recurve is defined as <br />the innermost recurving ridge that enters <br />the pattern area, recurves and exits or <br />tends to exit on the same side as the <br />ridge entered. The ridge must be free of <br />Any ridge appendages abutting at right<br />angles on the outside of the recurve <br />between the shoulders of the looping <br />ridge.<br />
  28. 28. Shoulder<br />The shoulders on looping ridges are considered the point at which the ridges begin to <br />curve or turn inward.<br />Shoulder<br />Shoulder<br />Ridge area that must be free of any<br />ridge appendages abutting at right<br />angles on the outside of the<br />Recurve.<br />
  29. 29. Sufficient Recurve<br />What do you do if the innermost<br />looping ridge is spoiled ? <br />This does meet the requirement <br />And is a sufficient recurve.<br />You move to the next recurve and determine <br />if it has a good recurve. This process <br />is followed until you get a good recurve<br /> or you are out of the pattern area.<br />Spoils the recurve look for <br />a sufficient recurve in the next<br />innermost looping ridge.<br />
  30. 30. Innermost sufficient recurve<br />Core<br />Core<br />Innermost sufficient<br /> recurve<br />Examples of the innermost recurving <br />ridges being spoiled and dropping back to <br />the next recurving ridge until you get a <br />recurving ridge that is not spoiled. Once <br />you have that you can determine the core <br />placement.<br />Innermost sufficient <br />recurve<br />Core<br />Innermost sufficient <br />recurve<br />
  31. 31. Ridge Counting<br />The ridge count is the number of ridges intervening between the delta and the core. The ridge count is usually <br />determined utilizing a red line found on the reticule of the fingerprint glass. The line is lined up between the delta <br />and core is used count to insure accuracy. Ridges that touch or cross the line become your ridge count, in the event <br />there is a bifurcation of a ridge exactly at the point where the imaginary line would be drawn, two ridges are <br />counted. Fragments and dots are counted as ridges only if they appear to be as thick and heavy as the other ridges <br />In the immediate pattern. The delta and core are not counted. Ridge counting was used extensively in the Henry <br />classification formula with the advent of automated fingerprint identification systems (AFIS) ridge counting is <br />seldom used though a ridge count across a looping ridge is a required element of a loop pattern. <br />Core<br />Delta<br />Ridge Count of 3<br />Ridge 3<br />Ridge 2<br />Ridge 1<br />
  32. 32. Quiz Correctly Identify<br />Type lines<br />Delta<br />Core<br />
  33. 33. Core<br />Core<br />Delta<br />Delta<br />Quiz Correctly Identify<br />Type lines<br />Delta<br />Core<br />Core<br />Core<br />Delta<br />Delta<br />