The encoding of the fingerprint papillary pattern

 

(57) Abstract:

The use of the invention for pre-treatment fingerprint fingerprint allows to increase the accuracy of their coding in the description. On papillary pattern distinguish papillary lines in all characteristic points, determine the direction of bending and curvature corresponding papillary lines, conduct of each characteristic point vector, tangent to the generatrix this point papillary lines, alternately select one of the characteristic points for the center of rotation of the scanning lines, which rotate, starting from the vector around the selected center of rotation, determine the angular coordinates of the scan line from its initial position for each encountered in the scanning characteristic point, and the angle from the initial position of the scan line to drawn through the observed point of the vector, define a metric distance and the number of Diablo papillary lines of the pattern between the selected center of rotation of the scanning lines and the observed characteristic point. The technical result is achieved by identifying large-scale characteristics (average distance between the papillary lines near cancerstick papillary pattern. 2 C. p. F.-ly, 12 ill.

The invention relates to raspoznavaniya images, namely the issues of pre-processing of graphic images, mainly of fingerprints and palm of hands by encoding, and can be used in forensics to identify prints papillary patterns.

There is a method to encode fingerprint papillary pattern of a finger, described in the international application 87/01224 System for recognition and search fingerprint" class G 06 K 9/00, published 26.02.87 priority of the United States from 16.08.85.

This method consists in the fact that the imprint of papillary pattern of finger pick the center of rotation of the scanning line, which is placed in the center of the print, radial scan pattern on its distinctive points, determining the geometrical features of the pattern in the vicinity of these points, by assigning a predetermined code to each of the characteristic points of the pattern depending on the type of characteristic points, i.e., encode start, end, merging, branching and other features of papillary lines. Then relative to the initial scanning lines passing through the center of the print, determine the angular coordinates of the scan line, the time between the center of rotation of the scanning lines and the characteristic points of the pattern. As a result of such coding are given numeric code, with some degree of certainty describing papillary pattern of the finger. The result of identification by the full imprint of papillary pattern of the finger is to issue a recommendation list.

For identification of partial fingerprint study the features of the distribution of characteristic points on it, the direction and contours of the papillary lines. Based on this information incomplete imprint restore to full (determine the estimated location of the center of the print in its fingerprint understanding), then encode in accordance with the above method and compare with your prints.

The disadvantage of this method is the low accuracy of coding even more complete and incomplete prints papillary patterns. This disadvantage is due to the fact that in this way the center of rotation of the scanning line placed in the center of the print, which passes through the initial scan line. As the center of the print is not the point, and a certain area, in this case it is impossible to determine the position of the point selected for the center of rotation of the scanning line, which may cause their distortion will occur when encoding and identification in the case of restoring the center of the pattern in incomplete imprint.

It should also be noted that the encoding of the print relative to the center of the pattern reduces the possibility of using this method, and it is not possible to encode and process the identification by fingerprints papillary pattern palms, because they cannot distinguish the center of the pattern, which should be adopted for the center of the scan.

The closest to the technical nature of the proposed method is a coding method of imprint papillary pattern. This method consists in the fact that the pattern allocate all characteristic points, determine the direction of the curve and the curvature of the papillary lines forming a data point, select the center of rotation of the scanning lines, for which accept any of the n feature points of the pattern, determine the initial position of the scanning lines, which take a vector drawn tangent to papillary line through a center of rotation of the scanning lines, radial scan pattern on its distinctive points, determine the angular position coordinates of characteristic points of the pattern relative to the starting position of the scan line, the angle from the initial position of the scanning lines to each of the (n-1) vectors carrying the Diablo line between the center of rotation of the scanning lines and the characteristic points of the pattern, then all operations is repeated (n-1) times, when the center of rotation of the scanning lines alternately each of the remaining (n-1) characteristic points of the pattern.

All operations of this method to encode fingerprint papillary pattern allows you to encode a picture of papillary pattern not only your finger, and the palm of your hand, then gives the opportunity to identify complete and incomplete prints papillary patterns of the fingers and the Palmar surfaces of the hands. It is connected with the exception of the ambiguity of the choice of the center of rotation of the scanning lines and the initial position of the scan line, the position of which is uniquely determined by the selected at this stage as the center of rotation of the characteristic point and the position vector drawn tangent to papillary line through a center of rotation. This method takes into account some geometrical features of papillary pattern, such as the direction of bending and curvature of papillary lines, forming a characteristic point of the pattern. This method eliminates the incomplete recovery of the print to the full, because the coding in this way is made by the characteristic points of the pattern without reference to the center of the patterns. This is due to the low information content of the known method that takes into account when encoding is not all geometric features of the structure of papillary pattern, and does not take into account the topological structure of the pattern. In addition, the use of the results of the coding of papillary pattern in this way to compare these patterns is possible only for prints, the images of which are made in the same scale, because otherwise the comparison will be making little reliable.

The purpose of the invention to improve the accuracy of coding of prints papillary patterns, including executed in arbitrary scales.

This is achieved by the fact that in the known method for encoding print papillary pattern, namely, that on the pattern allocate all characteristic points, determine the direction of the curve and the curvature of the papillary lines forming a data point, select the center of rotation of the scanning lines, for which accept any of the n feature points of the pattern, determine the initial position of the scanning lines, which take a vector drawn tangent to papillary line through a center of rotation of the scanning lines, the EC pattern relative to the starting position of the scan line, the angle from the initial position of the scanning lines to each of the (n-1) vectors, held tangentially to the papillary lines through (n-1) characteristic points of the pattern metric distances and the number of Diablo line between the center of rotation of the scanning lines and the characteristic points of the pattern, then all operations is repeated (n-1) times, when the center of rotation of the scanning lines alternately each of the remaining (n-1) characteristic points of the pattern, according to the invention additionally for each characteristic point of the pattern define a large-scale feature, reflecting the average distance between the papillary lines near the characteristic point, the converted metric distances, taking into account the large-scale characteristics of the points, the topological characteristics of the pattern, reflecting the direction of papillary lines forming the (n-1) characteristic point, relative to the direction of papillary lines, forming the center of rotation of the scanning lines, the location of each of the (n-1) specific points relative to the papillary lines, forming the center of rotation of the scanning lines, all types of n feature points and topological displacement of the characteristic points relative to the center of rotation of the scanning lines.

In the method according to p. I arithmetic mean value of the large-scale characteristics of all n characteristic points of the pattern, imprint oriented relative to a rectangular coordinate system, the x-axis which is directed along the base of the pattern, and the y-axis through the middle of the base of the pattern, determine the position coordinates of each characteristic point in this coordinate system and angles from the x-axis to each of the vectors held by the tangent to the papillary lines through arranged on specific points.

In the method according to p. 2 encode the internal features of "Delta" and "center" of the structure of papillary pattern, the number and position of these features in the pattern determines the type of papillary pattern, determine the position coordinates of the "deltas" and "centers" in the rectangular coordinate system, and features "center" determine the angle from x-axis to the vector pointing in the direction of continuation of the legs of the loop and perpendicular to the tangent line at the point most abrupt bending of the inner loop-like papillary lines, forming the characteristic "center", and define a metric distance and converted to metric distances, taking into account the General large-scale characterization of the pattern, determine the number Diablo lines between features of "Delta" and "center" of the pattern.

Perform all opengrok papillary pattern of finger and palm, allowing further with high reliability and minimal complexity to identify the person by encoded using the proposed method prints.

This advantage is due to the fact that the definition of large-scale characteristics of the points of the pattern and the overall large-scale characteristics of the entire papillary pattern, allows you to encode, and then compare with high accuracy papillary patterns, made in different scales (e.g., photographs).

This method takes into account the geometrical features and topological structure of papillary pattern that can uniquely and thoroughly describe any papillary pattern that leads to a significant reduction of recommendation list, resulting identificazione search, i.e. to reduce the complexity of personal identity.

The claimed method meets the criterion of "novelty", as characterized by the presence of the above symptoms, distinguishing it from the prototype.

The applicant is aware that the international application N 87/01224 System for recognition and search fingerprint" class. G 06 K 9/00, publ. 26.02.87 priority of the United States from 16.08.85, to the d, reflecting the type of point (branching, merging, start, end, etc).

The applicant is also known to encode papillary patterns using position coordinates of characteristic points in a rectangular coordinate system, relative to which it is oriented papillary pattern (see Lebedev, C. I. Ershov B. I., "Automated system for processing fingerprint "Point-1", the magazine "Expert practice", 1980, No. 16, pp. 55-57).

However, the applicant is not known technical solutions, of which explicitly follows the technical result achieved in the proposed method, using well-known and distinctive features of the prototype of essential features, therefore, the applicant believes that the proposed solution meets the criterion of "inventive step".

In Fig. 1 presents an incomplete query fingerprint papillary pattern of the finger of Fig. 2, 3, 4, 5 table templates to determine the topological characteristics of papillary pattern of Fig. 6 full query fingerprint papillary pattern, Fig. 7, 8, 9, 10, 11, 12 types of papillary patterns.

The encoding of the fingerprint papillary pattern is as follows. On the pattern allocate all characteristic points for Kazemi near each characteristic point. Through each characteristic point of the pattern of conduct vector directed along the tangent to the papillary lines forming this point.

Determine the geometric features of the pattern in the vicinity of each of the n points of the pattern, namely the relative position of the data vectors and papillary lines forming the characteristic point, determine the direction of the bend (i) papillary lines, and then determine the curvature (k) of these papillary lines.

Next in this pattern one of the characteristic points is chosen at the center of rotation of the scanning lines. For the initial position of the scanning lines (starting scan line) are vector drawn tangent to papillary line through a center of rotation of the scanning lines.

Then radial scan pattern, turning the initial scan line around the center of rotation up until this line will not reach the following specific points. Detect the angular position coordinate characteristic points relative to the initial scanning lines, that is, the angle (),describing the current position of the scan line, which is measured from the initial scan line to scan line passing through the mentioned characteristic is entrusted through a named point. Define a metric distance (r) between the center of rotation and the said point, the distance (R) taking into account the large-scale characteristics of both points. Determine the number (d) papillary (Diablo) lines between the center of rotation of the scanning lines and the characteristic point and determine the topological characteristic (P) of the mutual position of these points, reflecting direction (agree or counter) papillary lines forming these points, the position of characteristic points relative to the papillary lines, forming the center of rotation of the scanning lines, the types of these points, topological displacement of the characteristic points relative to the center of rotation of the scanning line.

Obtained values of the characteristics of the pattern is fixed. Then, the scan line is turned to the next characteristic point and all operations on the coding again. After the scan line passing through the characteristic points of the pattern will return to its initial position, the center of rotation consistently take every other characteristic points of the pattern and repeat all of the above operations of the encoding method.

If the print papillary pattern of finger display base pattern, which coincides with Mesut relative to a rectangular coordinate system, the x-axis which is directed along the base of the pattern, and the y-axis through the center of the base pattern. Determine for each characteristic point of the pattern coordinates x and y and the angle as the angle from the x-axis to each of the vectors held by the tangent to the papillary line through arranged on specific points. At the same time determine the overall scale characteristic m of the entire pattern, which is the arithmetic mean value of the large-scale characteristics of all characteristic points of the pattern. With this characteristics determine the values of the coordinates xIand yIall characteristic points of the pattern in the coordinate system relative to which it is oriented papillary pattern:

xIx/M; yIy/M; where M (m1+ m2+ mn)/n

n the number of characteristic points in the pattern

If the full imprint of papillary pattern show internal features of the structure of papillary pattern ("Delta" and "centers") in addition encode these features. Under the feature "Delta", encoded by the letter "D" means the place of separation of the three streams of papillary papillary lines of the pattern. Under the feature "center" encoded by letter, understand the place that the most abrupt bending of papillary lines "centers" determine the type of papillary pattern, the coordinates x and y, xIand yIthe provisions of the "deltas" of the "centres" of the pattern, placed in a rectangular coordinate system and define the metric distances and converted to metric distances and the number of Diablo lines between the "deltas" and "centers" of the pattern.

In addition, features "center" determine the angle () from the x-axis to the vector pointing in the direction of continuation of the legs of the loop and perpendicular to the tangent line at the point most abrupt bending of the inner loop-like papillary lines, forming the characteristic "center".

After that are the reference for the identification of the search.

The encoding of the fingerprint papillary pattern is as follows.

Received from the scene imprint papillary pattern codeable to received information about this pattern can then be used for identification search.

Assume that the scene is received incomplete, fragmentary fingerprint papillary pattern of the finger (Fig. 1).

At this fingerprint pattern allocate all characteristic points.

For each characteristic point of the pattern definition the number of papillary lines spend vector, directed along the tangent to the papillary lines forming this point, and drawing a line perpendicular to the vector. It should be noted that if the characteristic point of the pattern, such as, for example, point 1, formed by the merger of the two papillary lines or branching one line into two, the vector through this point spend tangent to the common part of these two papillary lines to their branching or after their merger. Perpendicular line extended in both directions from the characteristic point 1, crosses the papillary lines located near the characteristic point 1. Measure the length (l1) cut the line, bounded on both sides with some of papillary lines, and count the number meghreblian intervals (l1) on this interval. Define the major characteristics of m1this characteristic point 1, as the ratio of l1/b1.

Point l:

m1l1/b116 mm/line,

where l180 mm, b15 meghreblian periods.

Then choose the following characteristic point 2 of the pattern and, after construction similar to the construction for point 1, determine the large-scale characteristic point 2:

l2Laut large-scale characteristics of m3, m4.mnfor all other characteristic points of the pattern.

Then the relative position vector drawn tangent to papillary lines in the position of the characteristic point 1, and papillary lines, forming a given point 1, determine the direction of the bend i1line. If the vector is to the right of the papillary lines, the direction of bending i this line encode the sign " + " if the left is negative, if the vector is directed along a papillary line "0".

In this case, point 1 vector is to the left of the papillary lines, then i1"-".

For point 2, the vector is located to the right of the papillary lines, then i2"+".

Similarly, determine the direction of bending all the rest of papillary lines forming the characteristic points 3,4,n pattern (i3, i4.in).

Next, determine the curvature k3,k4.knpapillary lines in the vicinity of the characteristic points 1,2,n. (The curvature k of a line is determined as a value inversely proportional to the radius R of curvature, measured from the center of curvature to the line). For the characteristic point 1 R1100 mm, and the curvature k10,01 1/mm, for a point 2 R260 mm, the curvature k20,017 1/mm, and so the Finance. For the initial position of the scanning lines (starting scan line) are vector drawn tangent to papillary lines, through the button on her point 1, in the direction of increasing the number of papillary lines. Scan line, starting from its initial position, rotate around the center of rotation, for example, clockwise, up until this line will not reach the second characteristic point 2. Through this point 2 spend the vector directed along the tangent to the papillary lines in the direction of increasing the number of papillary lines.

Then define:

angle1275aboutdescribing the current position of the scan line and measured clockwise from the starting scan line to scan line passing through point 2;

angle12205aboutmeasured clockwise from the starting scan line to the vector drawn at a tangent through the point 2;

metric distance (r1240 mm), measured between the center of rotation of the scanning line and point 2;

the transformed metric distance R1240/(16 + 14) of 1.33, which is determined by the formula:

R12r12/(m1+ m2), where m1, m2mA interval from the center of rotation of this line to point 2;

topological characteristics (Peqreflecting the mutual position of the center of rotation of the scanning lines, the characteristic point of the pattern and papillary lines forming these points.

To help identify the topological characteristics (Peq) in Fig. 2, 3, 4, 5 shows a table of all possible variants of mutual arrangement of the two characteristic points and papillary lines forming these points (table templates). The table is based on empirically obtained data, which are systematized on the main characteristics characteristics (Peq). It should also be noted that the data in x and the other main and marked with "o", and in the tables papillary line, forming the main point is always directed from left to right.

The basic characteristics of the topological characteristics are.

The direction of papillary lines, forming the characteristic point q, referred to as a peripheral point, relative to the direction of papillary lines, forming a characteristic point e, is chosen as the center of rotation of the scanning lines and hereinafter called the principal point.

Believe that papillary line forming any characteristic point, always their papillary lines, forming a peripheral and the main point of the pattern code " + " sign and counter sign "-".

For point 1 (the main point) and 2 (peripheral) direction of papillary lines counter, therefore, this case encode the sign "-" (see Fig. 1).

In the tables of Fig. 2 and 3 shows the patterns of location of papillary lines agree with the direction code ( " + " ), and Fig. 4 and 5 in the opposite direction (code," -").

The peripheral location of point q relative to the papillary lines, forming the main point is.

Through the principal point in the direction of increasing the number of papillary lines conduct the vector directed along the tangent to the papillary lines, forming a given point, and a line perpendicular to a given vector (these builds have already been conducted in the determination of the large-scale characteristics of the point).

If papillary line, forming a main point, and the peripheral point located on one side from the above-mentioned perpendicular line, the location of the papillary lines and the peripheral points encode the letter "a" if they are on different sides of this line, then the letter "b" in case the location of the peripheral point on a strictly perpendicular the point 1 is located at one side of a perpendicular line, that such a disposition code of "a".

In the tables of Fig. 2 and 4 show such patterns of peripheral location of the point relative to the papillary lines forming the main point, which have a code "a", and Fig. 3, 5 with code "b".

Primary and peripheral points of the pattern. Point which is the beginning or the end of papillary lines, is coded "1", and the point formed by merging or branching papillary lines, is encoded by the numeral "2".

Based on the foregoing, the main point of 1 is assigned a code of "2", the peripheral point 2, the code "1", therefore the code for the pair of points 1 and 2 will be "21".

Just for this part of the characteristics of R can be four variants encoding: "11", "12", "21" and "22", where the first two-digit code is a figure indicating the type of base point, the second digit indicates the type of the peripheral points;

In the tables of Fig. 2, 3, 4, 5 are templates already systematized in columns: the first column of Fig. 2, 3, 4, 5 are templates for which the code of the main and peripheral pixels is equal to "11", the second column code "12" third code "21", and the fourth code "22".

Topological offset peripheral point pattern relative activities what's in tables 2, 3, 4, 5 rows, each of which is assigned a corresponding code: 0, +1, +2, +3, -1, -2, -3,

In line with the code "0" (zero line), shows the basic positions of the points and papillary lines for which line-by-line transformation of the mutual position of two points by moving the peripheral points with papillary lines of her form, relative to the main point and the associated papillary lines. There are cases when it is impossible to find the base (middle) position of the two points. Then this is the place in the zero line remains free.

In the rows with IDs +1, +2, +3 presents the cases, when a peripheral point is shifted upwards relative to the main point, that is gradually moving away from her so that between these points appear separating them from each other papillary lines.

On the tables (Fig. 2, 3, 4, 5) above the zero line is shown only rows with IDs from +1 to +3, but the tables indicate that further topological displacement of two points having codes +4, +5, etc. will only go by the number of dividing lines, the number of which is incremented in each subsequent row.

Similarly structured templates rows of the main points.

Let us consider separately the principle of design templates that are located in the fourth columns of tables Fig. 2, 4 and with codes +A22, -A22. Moreover, we note that in the area of education specific points in the branching papillary lines are formed like two branches, called hereinafter the upper sleeve and the lower sleeve, depending on their position in the template.

code+A22+. For this case, the null string is free. In the first top row (code+A22+1") place the template in which the lower sleeve peripheral point is located on the upper sleeve of the main points. In the second top row (code+A22+2") lower sleeve peripheral point is located above the upper sleeve main point. In the third top row (code+A22+3") between the lower sleeve peripheral point and the top of the sleeve main point is one papillary line. The following template (code+A22+4") between them will be two lines, and so on, that is, shows the gradual (step-by-step) offset peripheral point upward relative to the upper sleeve main point. In the first bottom row (code+A22-1") pattern, in which the upper sleeve peripheral point is located on the lower sleeve of the main points. In the second bottom row (code+A22-2") of the upper sleeve, the peripheral is shifted down relative to the lower sleeve of the main points.

code "-22". The zero line is the basic pattern, in which the upper sleeve main point coincides with the upper sleeve peripheral point and the lower sleeve main point coincides with the lower sleeve peripheral point. In the first top row (code-A22+1) is the pattern in which the peripheral point is shifted upward, and the lower sleeve peripheral point coincides with the upper sleeve main point, the upper sleeve peripheral point goes above the main point, and the lower sleeve main point passes below the peripheral points. In the second top row (code-A22+2") both sleeves peripheral points are above the sleeve main point. In the following the upper rows are templates, followed by an upward shift in the peripheral points relative to the main point. In the rows below the zero line are templates, which are similar displacement of the peripheral points down relative to the main point.

Similarly structured templates and other 14 table columns topological patterns (Fig. 2, 3, 4, 5).

Now that you have a full table of patterns that define the topological bias for point 1 (the main point) and 2 (peripheral point), for which three m "A21" there is a pattern in the string "-3", defines the topological location of points 1 and 2 on the encoded fingerprint papillary pattern.

Thus defined a complete topological characterization for points 1 and 2 of the encoding pattern (in the case where point 1 is the main, and point 2 is a peripheral point), which in this case is equal to

P12-A21-3.

The obtained values of all characteristics of papillary pattern is fixed, except for metric distances, which are minor, intermediate characteristics and identification search is not used.

Then, the scan line is turned to the next characteristic point 3, and all operations of encoding the position of point 3 with respect to the point 1 is repeated, as described above.

After the scan line passing through the characteristic points of the pattern will return to its initial position, the center of rotation of the scan line is transferred to position 2 and repeat all of the above operations, i.e. carry out the encoding of the mutual position of all other characteristic points of the pattern (points 1, 3, 4, and so on) in relation to point 2. Then the center of rotation of the take point 3 and so on

As a result, after such encoding the BR>i1k1m1(1212d12R12P12;1313d13R13P13;)

i2k2m2(2121d21R21P21;2323d23R23P23;)

i3k3m3(3131d31R31P31;3232d32R32P32;), which is then used as a source of information for identification of the search.

When drawing up plans for conducting a search set tolerances on the values of a characteristic pattern, which eliminates the influence of the errors arising from the characterization of the pattern, and also because of the distortion patterns caused by the deformation of the epidermis (the skin of the finger) at the time of ledoobrazovanie or other factors affecting the spatial distortion of papillary pattern.

The result of identification is a reference list that contains a list of user fingerprint codes which coincided with the code query fingerprint. Reference list sorted by total match all of the characteristics of each of your prints with characteristics for which. 6), this fold is taken for the base pattern. In this case, in addition when encoding papillary pattern imprint oriented relative to a rectangular coordinate system, the x-axis which is directed along the base of the pattern, and the y-axis through the middle of the base of the pattern.

In this system of coordinates define the coordinates x and y of each characteristic point, that is, the characteristics of x1, y1x2, y2and so on, as well as determine the angles1,2and so on, which is measured clockwise from x-axis to each of the vectors held by the tangent to the papillary lines located on them through specific points in the direction of increasing the number of papillary lines.

To allow for identification of the search, the authenticity of which is not dependent on a difference scale images scanned and request fingerprint (for example, when working with photos prints papillary patterns), when encoding fingerprint determine the overall scale characteristic m of each pattern:

M (M1+ m2+ mn)/n, where m1, m2,mnlarge-scale characteristics of the points 1,2,n pattern;

n is a number characteristic of the>, yIthe position of characteristic points of the pattern in the rectangular coordinate system, relative to which it is oriented papillary pattern;

xIx1/M, y1'y1/M etc.

In this case, the matrix codes papillary pattern complementary characteristics xI, yI:

x1Iy1I1i1k1m1(1212d12R12P12;1313d13R13P13;)

x2Iy2I2i2k2m2(2131d21R21P21;2323d23R23P23;)

x3Iy3I3i3k3m3(3131d31R31P31;3232d32R32P32;) and so on

In those cases, when in the full imprint show internal features of the structure of papillary pattern ("Delta" and "centres") (see Fig. 6) optionally encode these features of the pattern. The presence of features "Delta" (the place of separation of the three streams of papillary lines) encode the letter D, and the presence of the "center" (the place that the most abrupt bending of papillary lines forming a loop) encode the letter S.

Row" prints are divided into six types of papillary patterns:

arc simple code (I) where there are no "Delta" and "centers" (Fig. 7);

arc tent (code II), where one "Delta" and one "center" (Fig. 8), and "Delta" is located below the "center" between the legs, forming its hinges;

loop right (ID (III) where there is one "Delta" and one "center" (Fig. 9), and "Delta" is located to the left of "center";

loop left (code IV), where one "Delta" and one "center" (Fig. 10), and "Delta" is located to the right of "center";

zawodowy pattern (code V), where there are two "Delta" and two centers (Fig. 11);

lonesomeday pattern code (VI) where there are three "Delta" and three centers (Fig. 12).

So, shown in Fig. 6 imprint refers to Zavidovo type (code V).

To encode the feature of "Delta" are in the form of a triangle, the sides of which are formed tangent conducted to papillary lines forming this feature. Find the center of gravity of the triangle, located at the intersection of the medians, and determine the coordinates of the center of gravity xD, yDand xDIyDIin a rectangular coordinate system, which are the coordinates of the internal features of the Delta (Fig. 6).

For the feature "is here, which in a rectangular coordinate system define the coordinates xCyCand xCI, yCIwho are the coordinates of the features of the "center" (Fig. 6).

In addition, for the feature "center" determine the anglewithmeasured clockwise from x-axis to the vector drawn towards the continuation of the legs of the loop is perpendicular to the tangent line at the point of the steepest curve of internal lines (loops) features "center" (see Fig. 6).

Then define the metric distances (rD1D2) between the "deltas" of the pattern (rC1C2between the "centers" of the pattern and (rD1C1, rD1C2.) between the "deltas" and "centers" of the pattern. These distances are measured between the same points that were used to determine the coordinates of the internal features of "Delta" and "center" in a rectangular coordinate system. Then, given the overall large-scale characterization of M, define the transformed metric distances (RD1D2, RC1D2, RD1C1, RD1C2and so on, according to the General formula R r/m

In addition, determine the number Diablo lines (dD1D2dC1C2dD1C1and so on ) between all features "Delta" and "center" of the pattern.

If, for example, in attach the Chatka papillary pattern complementary to the type of the pattern and characteristics of these features:

U

All operations on the coding of the prints can be done by computer or manually, as described above.

Application of the proposed method of encoding imprint papillary pattern in comparison with the above-described known can improve the accuracy of identification by fingerprint papillary pattern by increasing the accuracy and informativeness of its coding. While the inventive method allows to reduce and simplify the process for identification of the search due to the fact that the comparison of fingerprints are first on the characteristics of the internal features of papillary pattern, which greatly reduces the number of prints, which are then compared to characteristics characteristic points.

1. The ENCODING of the FINGERPRINT PAPILLARY PATTERN, which includes the selection of a papillary pattern of papillary lines in all its characteristic points by the number n, the determination of the direction of bending and curvature forming each characteristic point of papillary lines, provedenie of each characteristic point of the vector tangent to the generatrix of this characteristic point of papillary lines, selecting one of the characteristic points for the rotation center line, scanning papillary pattern by rotating the scanning lines around the selected center of rotation, the definition of angular coordinates relative to the starting position of the scan line for each encountered during scanning of the characteristic points, the determination of the angle from the initial position of the scan line to drawn through the observed characteristic point of the vector, the definition of metric distances and number of Diablo papillary lines of the pattern between the selected center of rotation of the scanning lines and the observed characteristic point, repeat all operations for scanning papillary pattern n - 1 times when the centre of rotation of the scanning lines of the new characteristic point, characterized in that for each characteristic point of papillary pattern define a large-scale characteristic of the characteristic point as the average distance between the papillary lines near this characteristic point, and then determine the transformed taking into account the large-scale characteristics of metric distances and topological characteristics of papillary pattern (a) direction relative to the papillary line with the center of rotation of the scanning lines of the rest of papillary lines, treatment is with the center of rotation of the scanning lines, (C) all types of characteristic points and (d) topological displacements of characteristic points relative to the center of rotation of the scanning lines.

2. The method according to p. 1, characterized in that it further determine the broad-scale characterization of papillary pattern as a medium-arithmetic value of a scale characteristics of all characteristic points of papillary pattern, along the base of which Orient the x-axis of a rectangular coordinate system, the y-axis which passes through the middle of the base, and define this rectangular coordinate system the position of each characteristic point and the angle from x-axis to the tangential velocity vector in this characteristic point of the generatrix of its papillary lines.

3. The method according to p. 2, characterized in that it further encode the internal features of "Delta" and "center" of the structure of papillary pattern, the number and position of which determines the predefined type papillary pattern and the coordinates of these features, especially the "center" determine the angle from x-axis to the vector, held normal to the tangent of the inner loop papillary line features "center" in the point of its greatest curvature and directional from this t is astonia with regard to the overall large-scale features of papillary pattern and the number of Diablo lines between features of "Delta" and "center" of the structure of papillary pattern.

 

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