JP3968521B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus for reading image data such as a fingerprint pattern.

  In recent years, as a device for identifying a person, a pattern matching device (image reading device) that reads a person's fingerprint pattern as image data and identifies the person by executing a matching process on the fingerprint pattern is used. It has become like this.

  As a mechanism for reading a fingerprint pattern using a conventional one-dimensional image sensor, a transparent flat plate is provided on the sensing unit, which is the fingerprint pattern reading position, and an illumination light source and a rod lens group (Selfoc lens) are provided below it. And a structure in which a one-dimensional image sensor is arranged.

  On the other hand, an image data reading device using a transparent rotating roller as a mechanism for reading a fingerprint pattern is considered (for example, see Patent Document 1). In a reading apparatus using a transparent rotating roller, a fingerprint image of a pressed portion is read by an imaging element by moving the finger while pressing the transparent rotating roller.

Further, in the image reading apparatus of Patent Document 1, a rotation detection print pattern is provided at a predetermined position of the transparent rotation roller, and the image pattern of the print pattern is read together with the image data of the fingerprint pattern by the image pickup device, and this rotation detection In response to the pattern change, an image pattern of a fingerprint pattern to be verified is generated. This eliminates the need for a rotation detection sensor for detecting image data reading timing.
JP 2002-133402 A

  As described above, in the conventional image reading apparatus (Patent Document 1), a rotation pattern is detected by adding a print pattern to a part of the transparent rotation roller, reading the print pattern with an image sensor, and detecting the rotation of the roller. Although the sensor can be dispensed with, there are the following problems.

  In Patent Document 1, an equal pitch pattern parallel to the rotation axis of the roller is used as the rotation detection pattern. With this equal pitch pattern, the position can be determined in a blank section between the rotation detection patterns. First, all the data between the rotation detection patterns can be held, and the reading timing of the data taken in the rotation detection pattern blank section can be grasped only when the next rotation detection pattern is detected. For this reason, the minimum rotation speed of the roller has to be guaranteed for realization, and a sufficient storage area for storing data taken in the blank section is required.

  The present invention has been made in view of the above-described problems, and is capable of realizing stable and high-quality image reading using a rotation detection pattern attached to a roller with high accuracy. An object is to provide an apparatus.

According to the first aspect of the present invention, there is provided a transparent rotating roller having a hollow inside, a one-dimensional imaging device installed inside the transparent rotating roller, and the one-dimensional imaging device as the finger is pressed against the transparent rotating roller. An image reading apparatus having an image reading means for reading a captured fingerprint image, wherein the transparent rotating roller includes two linear portions each having a certain angle with respect to the rotating roller axis and continuously forming a triangular wave. pattern is assigned over one round of the outer peripheral surface so as to be line-symmetrical with Rutotomoni are added parallel line patterns with respect to the rotating roller shaft at the apex of the peaks and valleys of the triangular wave in order to determine the period the image reading means, a center position detecting means for detecting a center position of the image corresponding to the two patterns that have been read in conjunction with the fingerprint image by the 1-dimensional image sensor, wherein in Characterized in that based on the center position detected by the position detecting means and a position correcting means for correcting the position of the fingerprint image read by the one-dimensional image sensor.

According to a second aspect of the present invention, in the first aspect of the present invention, there is provided a judging means for judging whether or not images corresponding to the number of lines determined corresponding to a period determined by the triangular wave pattern are recorded, and lines of the recorded images. In the case where the number of lines does not reach the determined number of lines, there is provided means for supplementing the number of unreachable lines with the image read in the next cycle .

According to the present invention, since the center position of the image corresponding to the two patterns is detected and the position of the fingerprint image read by the one-dimensional image sensor is corrected based on the center position, a high-quality fingerprint image is generated. can do.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an electronic circuit of a mobile phone equipped with an image reading apparatus according to an embodiment of the present invention. The cellular phone is configured by a computer that reads a program recorded on a recording medium and whose operation is controlled by the read program.

  The mobile phone shown in FIG. 1 includes a CPU 10 connected to various devices such as a storage device 12, a RAM 14, a call unit 16, a display unit 18, a key unit 19, and a fingerprint reading unit 20 via a bus. . The fingerprint reading unit 20 reads an image of a fingerprint pattern on the fingertip using the subject as a human fingertip.

The CPU 10 implements various functions by executing programs stored in the program area of the RAM 14. In addition to controlling the function of the mobile phone, the CPU 10 executes fingerprint pattern image data reading control by the fingerprint reading unit 20 and various processes for the image pattern.
The storage device 12 stores programs, data, and the like and is read out as necessary and stored in the RAM 14.

  The RAM 14 stores programs and various data and is accessed by the CPU 10. In addition to various programs for controlling the mobile phone, the RAM 14 executes a processing program for executing processing on the image data of the fingerprint pattern read by the fingerprint reading unit 20. Is stored. When the fingerprint reading unit 20 reads the image data of the fingerprint pattern, the read image data is stored.

The call unit 16 is a unit for performing wireless communication as a mobile phone.
The display unit 18 displays various data when executing various functions realized by the CPU 10.
The key unit 19 includes a plurality of keys including numeric keys for inputting telephone numbers and various function keys.
The fingerprint reading unit 20 reads image data representing a fingerprint pattern, and is provided at a position where the fingerprint reading operation is easy, for example, at the top of the front surface as shown in the appearance example of the mobile phone in FIG. The fingerprint reading unit 20 in the present embodiment includes a light source 21, a lens optical system (selfoc lens 22), a one-dimensional imaging device 24, an imaging control circuit 26, an A / D conversion circuit 28, and a transparent rotating roller 29. In addition, a part of the outer peripheral surface of the transparent rotating roller 29 is exposed to the outside through a slit provided in the casing of the mobile phone. The exposed portion of the transparent rotating roller 29 becomes a fingerprint pattern reading portion. When reading a fingerprint pattern, a fingertip as a subject is pressed against the reading unit, and the transparent rotating roller 29 is rotated in a predetermined direction (a direction perpendicular to the rotation axis of the transparent rotating roller 29) in that state. It is done by moving while. The slit provided on the surface of the casing may be wide enough to allow the user to rotate the transparent rotating roller 29 by pressing the fingertip against the transparent rotating roller 29. Therefore, in order to read the image of the fingerprint pattern, it is not necessary to secure a reading surface on which the entire fingerprint fits, and the mounting area of the fingerprint reading unit 20 (transparent rotating roller 29) on the surface of the housing may be small.

  In the fingerprint reading unit 20, the light reflected from the fingertip that is an object irradiated from the light source 21 and pressed (contacted) with the reading unit passes through the transparent rotating roller 29 and is applied to the one-dimensional imaging device 24 by the Selfoc lens 22. Focused. Under the control of the imaging control circuit 26, the light condensed through the Selfoc lens 22 is photoelectrically converted by the one-dimensional imaging device 24, and further converted by the A / D conversion circuit 28 as image data representing a fingerprint pattern. For example, data is periodically read from the one-dimensional imaging device 24 at a timing of 20000 times / second, and the data is buffered in the RAM 14. The CPU 10 changes the rotation detection image obtained by reading the portion of the rotation detection pattern 30 attached to the transparent rotation roller 29 with respect to the data read by the one-dimensional imaging device 24 (predetermined line portion). In the case where a deviation occurs), it is captured as image data and recorded in the RAM 14 as an image of a fingerprint pattern.

FIG. 3 shows a schematic configuration (side sectional view) of a mechanism portion of the fingerprint reading unit 20.
As shown in FIG. 3, the casing of the mobile phone is provided with a slit along the rotational axis of the transparent rotating roller 29 so that a part of the outer peripheral surface of the transparent rotating roller 29 is exposed as a fingerprint pattern reading unit. ing. The transparent rotating roller 29 is made of a transparent material such as acrylic or glass so that light can be transmitted, and is mounted so as to rotate with a part of the outer peripheral surface exposed from a slit provided in the housing. . The transparent rotating roller 29 has a hollow inside. The light source 21 (for example, LED (Light Emitting Diode)), a lens optical system (Selfoc lens 22), and the one-dimensional image sensor 24 are formed in the hollow. An imaging function unit including is mounted. These imaging function units are mounted so as not to be interlocked with the rotation of the transparent rotating roller 29.

  The Selfoc lens 22 forms an image on the one-dimensional image sensor 24 at a portion (reading unit) where the subject is pressed against the transparent rotating roller 29. In addition, it is not restricted to a Selfoc lens, It is possible to use the imaging optical system comprised by a rod lens group.

  Although not shown, an optical correction element can be mounted between the transparent rotating roller 29 and the Selfoc lens 22. The optical correction element is for correcting an optical influence, that is, a distorted image due to the curvature of the transparent rotating roller 29 at a portion where the fingertip as a subject is pressed, and is, for example, a convex lens, specifically, one surface is flat and opposite. It is assumed that the surface is constituted by a cylindrical lens having a convex curved surface and has a curvature equal to or close to the inner diameter of the transparent rotating roller 29.

  The one-dimensional image sensor 24 is configured by a CCD line sensor, a CMOS line sensor, or the like, and is mounted so that the arrangement of the image sensors is parallel to the rotation axis of the transparent rotary roller 29. For example, the one-dimensional imaging element 24 has an imaging range corresponding to the length of the transparent rotating roller 29, and an image including a rotation detection pattern 30 added to an end (or near the end) of the transparent rotating roller 29 described later. Can be read. The transparent rotating roller 29 is hollowed and the imaging function unit is mounted therein, thereby reducing the mounting area of the fingerprint reading unit 20 on the casing surface and the mounting volume in the casing.

  For example, a pattern formed by making the surface shape of the outer peripheral surface non-uniform is attached to the transparent rotating roller 29. FIG. 4 is a perspective view showing the appearance of the transparent rotary roller 29 provided with the rotation detection pattern 30, and FIG. 5 is a plan view of a portion corresponding to the rotation detection pattern 30. 4 and 5 has a step shape in which the cross-sectional shape of the shaft of the transparent rotating roller 29 is changed stepwise in outer diameter, and a rotation detection pattern 30 including two patterns of the same shape is provided. It is attached over one circumference of the outer peripheral surface.

  The rotation detection pattern 30 has, for example, a smooth mirror finish on the outer peripheral surface of the transparent rotating roller 29, and this outer peripheral surface portion is detected as a dark portion (that is, black) by the one-dimensional imaging device 24, and a boundary portion, that is, a step portion. However, the light from the light source 21 is irregularly reflected, so that it is detected as a bright part (that is, white).

  The two patterns forming the rotation detection pattern 30 have alternating linear portions (linear portions each having a fixed angle with respect to the axis) that are symmetrical with respect to the axial direction of the transparent rotating roller 29 at a predetermined angle. It is formed so as to be continuous, that is, a triangular wave shape in which the angles of the peaks and valleys are the same. As the predetermined angle, for example, in the rotation detection pattern 30 shown in FIGS. 4 and 5, the angle θ (−θ) with respect to the axial direction of the transparent rotary roller 29 is preferably 45 ° (tan θ = 1) or 45 °. It is in the vicinity (vertex angle is 90 °). The two patterns are arranged such that the peak portion of one pattern and the valley portion of the other pattern coincide with each other in the direction of the rotation axis of the transparent rotating roller 29. Are line symmetric. Thereby, based on the change in the difference between the positions of the two rotation detection images obtained by reading the two patterns, the rotation of the transparent rotation roller 29, that is, the timing for outputting the image data of the fingerprint pattern is determined. Thus (FIG. 7 described later), the amount of change can be doubled as compared with the case of determining the output timing based on the position change of the image when one pattern is used.

  The rotation detection pattern 30 attached to the transparent rotation roller 29 shown in FIGS. 4 and 5 is an example, and other shapes of the rotation detection pattern 30 will be described later (FIGS. 10, 11, and 13). To FIG. 16, FIG. 18 to FIG. 21).

  In FIG. 3, the light source 21 is provided in the hollow of the transparent rotating roller 29. However, the transparent rotating roller 29 may be arranged at a rotating shaft position, for example, near the end surface. By arranging the light source 21 in the vicinity of the end face of the transparent rotating roller 29, the transparent rotating roller 29 is used as a light guide to capture the light flux from the light source 21, and irradiate the fingertip (subject) in contact with the reading unit. The reflected light can be read by the one-dimensional image sensor 24. The light source 21 can be constituted by, for example, an LED, a fluorescent tube, a halogen lamp, or the like.

  Further, the rotation detection pattern 30 is formed by making the cross-sectional shape of the axis of the transparent rotation roller 29 into a stepped shape whose outer diameter changes stepwise, but other methods such as printing are used. It may be attached.

  FIG. 6 shows a correspondence relationship between the rotation detection pattern 30 attached to the transparent rotation roller 29 and the image sensor of the one-dimensional image sensor 24. As shown in FIG. 6, the one-dimensional image sensor 24 has the entire length of the transparent rotating roller 29 as a photographing range, and the number (N) of image sensors corresponding to the rotation detection pattern 30 is known. Suppose that it is used in various processing mentioned below.

(First embodiment)
Next, the operation of the image reading apparatus in the first embodiment will be described.
In the image reading apparatus according to the first embodiment, since a sensor for detecting the rotation of the transparent rotating roller 29 is not provided, regardless of whether the transparent rotating roller 29 is rotated, for example, at a cycle of 20000 times / second. Capture image data continuously.

  The image data read by the one-dimensional image sensor 24 includes a rotation detection image corresponding to the rotation detection pattern 30 added to the transparent rotation roller 29.

  The CPU 10 detects the rotation of the transparent rotating roller 29 based on the image data read by the one-dimensional image sensor 24 by a timing determination process to be described later, and the subject necessary as the transparent rotating roller 29 rotates is detected. Only when it is determined that image data has been input, the image data is stored as fingerprint image data of the subject.

  Next, the half-cycle image data acquisition process in the first embodiment will be described with reference to the flowchart shown in FIG. In the fingerprint reading unit 20 according to the first embodiment, the rotation detection pattern 30 attached to the transparent rotation roller 29 is in a range corresponding to half of the repetitive pattern attached to the transparent rotation roller 29, that is, by the one-dimensional image sensor 24. It is assumed that the range that is read from the peak portion to the valley portion is a half cycle (read range), and the number of lines of an image that is captured in this half cycle is determined. The fingerprint reading unit 20 acquires (records) image data for a half cycle by a process according to the flowchart shown in FIG.

  First, as initialization processing of the half-cycle image data acquisition process, the CPU 10 sets the half-cycle acquisition image reference number N (step A1) and sets the half-cycle acquisition image data number M to “0” (step A2). ).

  The CPU 10 extracts a portion corresponding to a line segment forming the rotation detection pattern 30 from the image data output via the A / D conversion circuit 28 of the fingerprint reading unit 20, that is, two rotation detection images (step). A3). Here, it is determined whether the data read by the one-dimensional image sensor 24 is white or black. Simply, the average value of the maximum and minimum pixel values of data read by the one-dimensional image sensor 24 is used as a threshold value, and data having a pixel value larger than this threshold value is white, otherwise black. Judgment can be made.

  FIG. 8 is a diagram showing the rotation detection pattern 30 attached to the transparent rotation roller 29 in a flat shape for easy understanding. The one-dimensional image pickup device 24 reads an image parallel to the rotation axis direction with respect to the transparent rotation roller 29, that is, in the horizontal direction in FIG. Accordingly, the hatched portions of the two rotation detection images forming the rotation detection pattern 30 can be detected by one reading by the one-dimensional image sensor 24.

  Here, the CPU 10 calculates the center position of the two rotation detection images (step A4), and based on the rotation detection image based on a predetermined reference position (for example, an ideal center position or a reference line). The difference (deviation) between the calculated center position and the center position of the two rotation detection images is calculated (step A5). Then, the horizontal position of the image is corrected according to the calculated shift amount, that is, the image data for one line is shifted right or left by the shift amount (step A6).

  The transparent rotating roller 29 has a structure in which the roller rotates. When the fingerprint pattern is read, that is, in a state where the fingertip that is the subject is in pressure contact with the transparent rotating roller 29, the transparent rotating roller 29 may be laterally shifted in the horizontal direction. Further, when manufacturing the transparent rotating roller 29, there may be a case where manufacturing accuracy varies. Therefore, based on the position correction pattern 32 attached to the transparent rotating roller 29, the read image is corrected according to the lateral displacement of the transparent rotating roller 29.

FIG. 9 shows an example of a rotation detection image for a plurality of lines.
In the case of the image data shown in FIGS. 9A1 to 9A4, the center positions of the two rotation detection images extracted from each of the image data coincide with the reference position, and thus no deviation correction is necessary.

  On the other hand, in the case of the image data shown in FIGS. 9B1 to 9B4, the center positions of the two rotation detection images are different from the image data of other lines in the image data of FIG. 9B3. Yes. In FIG. 9 (b3), since the center position calculated from the two rotation detection images is on the right side of the reference position, the position shift is corrected by shifting to the left side.

  Next, the CPU 10 calculates the difference between the positions of the two rotation detection images (the distance between the images) (step A7). Here, when the difference between the positions of the two rotation detection images is reversed (decreased or increased) from the change trend of the difference in the image data to be processed so far, that is, from the situation where it has increased or decreased. Then, the processing is terminated assuming that the processing for the half-cycle image data has been completed (step A8, Yes). In the vicinity of the apex of the triangular wave pattern, the increase / decrease in the distance between the rotation detection images occurs. However, the inversion at the apex can be detected if the maximum (minimum) distance (difference) is compared as needed.

  On the other hand, when there is no increase / decrease / inversion of the difference between the two rotation detection images (step A8, No), the CPU 10 determines that the difference between the positions of the two rotation detection images is the target image at the time of the previous image output. It is determined whether the difference calculated from the data is, for example, more or less than two pixels (step A9).

  That is, when it is determined that the transparent rotating roller 29 is rotated in a state in which the subject is pressed and a new part of the subject has moved to a reading position by the one-dimensional imaging device 24 (Yes in step A9), the image It is determined that it is the capture timing.

  Here, whether the number of acquired image data (number of lines) has reached the half-cycle acquired image reference number N (M = N), that is, whether image data to be acquired for the half cycle has already been secured. It discriminate | determines (step A10).

  Here, when the half-cycle acquired image data number M has not reached the half-cycle acquired image reference number N (step A10, M <N), the CPU 10 counts up the number of image outputs, that is, M = M + 1. The number M of half-cycle acquired image data is updated (step A11).

  Then, the image data read by the one-dimensional image sensor 24 is output (recorded) as an image representing a fingerprint pattern (step A12).

  On the other hand, when the number of half-cycle acquired image data M (the number of lines) reaches the half-cycle acquired image reference number N (step A10, M = N), the read image data is discarded. Then, the process returns to step A3. Until the increase / decrease inversion of the difference is detected (step A8, Yes), the read image data is continuously discarded (steps A3 to A10).

  Thus, the movement of the position of the portion corresponding to the line segment of the rotation detection pattern 30 of the rotation detection image, that is, the difference between the positions of the two rotation detection images is 2 pixels or more from the previous image output. It is determined that it is the capture timing, and an image of a fingerprint pattern composed of image data of the number of lines corresponding to the half-cycle acquired image reference number N can be generated.

  Thus, in the first embodiment, a change in the difference between the positions of the two rotation detection images detected by reading the rotation detection pattern 30 is determined as a change in the rotation of the transparent rotation roller 29. Therefore, by using the rotation detection image having the same oblique line angle of the rotation detection pattern 30 as the rotation detection image, it is possible to obtain a change amount twice as large as the position change of the image read from one pattern. Therefore, the timing for outputting (recording) image data with high accuracy can be determined, and an image representing a fingerprint pattern with high quality can be generated. Also, if the amount of change is the same as when using one pattern, the width of the range necessary for adding the rotation detection pattern 30 can be narrowed. That is, the range necessary for adding the rotation detection image of the transparent rotation roller 29 can be narrowed to widen the fingerprint pattern reading range.

  Furthermore, even if the play (position fluctuation) in the rotation axis direction of the transparent rotating roller 29 occurs, the distance (difference) between the rotation detection images is not affected. There is no need for addition, and processing can be simplified.

  Further, by correcting and outputting the center line of the positions of the two detected rotation detection images as virtual vertical lines, it is possible to generate an image representing a good fingerprint pattern without lateral deviation for each line. it can.

  The lateral deviation correction for each line is performed by generating an image representing a fingerprint pattern and then calculating information regarding the deviation for each line (deviation amount, deviation direction, etc.) calculated in steps A4 and A5. It is also possible to execute a lateral position correction process that performs correction collectively.

  In the above description of the half-cycle image data acquisition process, after performing position correction on the two rotation detection images extracted in step A3 (steps A4 to A6), the difference between the two rotation detection images. Is calculated to detect increase / decrease inversion (switching) of the difference (steps A7, A8), but position correction may be executed before outputting the image data. That is, since the processing is performed based on the difference between the two rotation detection images for each line, the same processing result can be obtained without correcting the position for each line in advance. Thus, the processing load can be reduced by executing the correction process only for the image data of the line used as the image of the fingerprint pattern.

Next, an example of another shape of the rotation detection pattern 30 attached to the transparent rotation roller 29 will be described.
FIG. 10 is a perspective view showing an external configuration of the transparent rotating roller 29, and FIG. 11 is a diagram showing a portion corresponding to the rotation detection pattern 30 in a flat shape.

  The two patterns forming the rotation detection pattern 30 shown in FIGS. 10 and 11 are line symmetric with the angle θ with respect to the axial direction of the transparent rotating roller 29 being preferably 63.5 ° (tan θ = 2) or the vicinity thereof. Are formed in a triangular wave shape such that the angles of the vertices of the peaks and valleys are 126.8 °. Similarly to the rotation detection pattern 30 shown in FIGS. 4 and 5, the two patterns have a peak portion of one pattern and a portion of the other pattern valley in the direction of the rotation axis of the transparent rotation roller 29. It arrange | positions so that it may correspond and it is axisymmetric with respect to the intermediate | middle line of two patterns.

  Thus, by increasing the angle θ with respect to the axial direction of the transparent rotating roller 29, the width in the axial direction necessary for adding the rotation detection pattern 30 to the transparent rotating roller 29 can be further reduced. Accordingly, the fingerprint pattern reading range of the transparent rotating roller 29 can be widened.

  In addition, the rotation detection pattern 30 shown in FIGS. 4, 5, 10, and 11 described above is a pattern composed of continuous diagonal lines that are two line targets, but along each vertex portion of the triangular wave along the axial direction. A horizontal line pattern may be added. By extracting the image of the horizontal line pattern, it is possible to detect the inversion in the increase / decrease direction of the difference between the two rotation detection images corresponding to the half cycle that is the image data acquisition range, that is, the triangular wave pattern.

  FIG. 12 shows a flowchart (partial) of the half-cycle image data acquisition process when a horizontal line pattern is added to the rotation detection pattern 30. The flowchart shown in FIG. 12 shows processing executed in place of steps A7, A8, and A9 shown in FIG. 7, and the processing of each step in the flowchart shown in FIG. 7 is executed for other processing. Detailed description is omitted.

  FIG. 13 is a perspective view showing the appearance of the transparent rotating roller 29 provided with the rotation detection pattern 32, and FIG. 14 shows a plan view of a portion corresponding to the rotation detection pattern 32. As shown in FIG.

  The rotation detection pattern 32 shown in FIGS. 13 and 14 is different from the rotation detection pattern 30 shown in FIGS. 4 and 5 in that the peak of the peak portion of one pattern and the vertex of the valley portion of the other pattern , That is, a horizontal line pattern parallel to the axis of the transparent rotating roller 29 is attached. In the example shown in FIG. 14, the horizontal line patterns attached to the two triangular wave patterns are all the same length. May be.

  FIG. 15 is a perspective view showing the appearance of the transparent rotary roller 29 provided with a rotation detection pattern 32 having another shape, and FIG. 16 is a plan view of a portion corresponding to the rotation detection pattern 32 corresponding to FIG. An expanded view is shown.

In the rotation detection pattern 32 shown in FIGS. 15 and 16, a short horizontal line pattern is attached to each vertex of the two patterns with respect to the rotation detection pattern 30 shown in FIGS.
The rotation detection pattern 32 shown in FIGS. 13 to 16 can also be applied to the rotation detection pattern 30 shown in FIGS. 10 and 11.

  When the transparent rotation roller 29 with the rotation detection pattern 32 shown in FIGS. 13 to 16 is used, when the rotation detection image is extracted from the image data read by the one-dimensional image sensor 24, the CPU 10 It is determined whether the type of the extracted rotation detection image is a portion corresponding to a horizontal line pattern or a portion corresponding to a diagonal line (step A13). In the case of the portion corresponding to the horizontal line pattern, the direction in which the horizontal line pattern is attached coincides with the reading direction by the one-dimensional imaging device 24, and therefore the pixels corresponding to the pattern are read in a continuous state. Therefore, it can be determined whether the extracted rotation detection images are continuous or dots.

  Here, if the portion corresponds to the diagonal line of the rotation detection pattern 32, the CPU 10 calculates the difference between the positions of the two rotation detection images (the distance between the images) in the same manner as in step A7 shown in FIG. (Step A14).

  Then, it is determined whether or not it is time to output the image data with the movement amount in the difference increasing / decreasing direction (step A15). That is, in the same manner as in Step A9 shown in FIG. 7, if the difference between the positions of the two rotation detection images is greater than the difference calculated from the image data targeted at the previous image output, for example, 2 pixels. It is determined whether or not the number has increased.

  Here, when it is determined that the output timing of the image data is reached, if the number of acquired image data (number of lines) does not reach the half-cycle acquired image reference number N, this image data is output as an image representing a fingerprint pattern. (Record. If it is determined that it is not the output timing of the image data, the process returns to step A3.

  On the other hand, if it is determined in step A13 that the type of the extracted rotation detection image is a portion corresponding to the horizontal line pattern, the CPU 10 reverses the direction of increase / decrease of the difference, that is, ends the image data acquisition process for a half cycle. Then, the process proceeds to the next half-cycle image data acquisition process.

  In this way, by setting the rotation detection pattern 32 including the horizontal line pattern, it is possible to stably determine the switching of the half cycle based on the rotation detection image. It is possible to reliably generate a fingerprint pattern composed of image data corresponding to.

(Second Embodiment)
Next, the operation of the image reading apparatus in the second embodiment will be described.
In the second embodiment, in addition to the half-cycle image data acquisition process in the first embodiment, when the image data (line) acquired in the half cycle has not reached the half-cycle acquired image reference number N, the following The shortage is compensated by using image data read in a half cycle.

  FIG. 17 is a flowchart illustrating a half-cycle image data acquisition process according to the second embodiment.

  In the flowchart shown in FIG. 17, detailed description of steps B1 to B7 is omitted because the same processing as steps A1 to A7 in the flowchart shown in FIG. 7 in the first embodiment is executed.

  If it is determined in step B8 that there is no increase / decrease inversion of the difference between the two rotation detection images, the CPU 10 calculates the difference between the positions of the two rotation detection images from the image data targeted at the previous image output. For example, it is determined whether the difference is more or less than two pixels (step B9).

  Here, when it is determined that the difference is two or more images, the CPU 10 determines that it is an image capture timing (step B9, Yes).

  Here, the number of half-cycle acquired image data M (number of lines) so far has reached the half-cycle acquired image reference number N (M = N), that is, image data to be acquired for the half cycle has already been secured. (Step B13).

  Here, if the half-cycle acquired image data number M has not reached the half-cycle acquired image reference number N (step B13, M <N), the CPU 10 counts up the number of image outputs, that is, M = M + 1. The number M of half-cycle acquisition image data is updated (step B14).

  Then, the image data read by the one-dimensional image sensor 24 is output (recorded) as an image representing a fingerprint pattern (step B12).

  On the other hand, when the number of acquired image data (number of lines) has reached the half-cycle acquired image reference number N (step B13, M = N), the read image data is discarded, The process returns to step B3.

  On the other hand, when there is no increase / decrease / inversion of the difference between the two rotation detection images (step B9, No), the CPU 10 has insufficient reading during the half-cycle image data acquisition process for the previous half-cycle. The value of P (hereinafter referred to as insufficient data number P) indicating the number of data (lines) is P> 0, that is, the image data output (recorded) in the half-cycle image data acquisition process for the previous half-cycle. Is less than the number M of half-cycle acquired image data (step B10). The insufficient data number P is set in step B15 described later.

  Here, if P> 0, that is, if there is a deficiency in the previous half cycle, the CPU 10 counts down the deficient data number P, that is, updates the deficient data number P as P = P−1 ( (Step B11) The image data read by the one-dimensional image sensor 24 is output (recorded) as an image representing a fingerprint pattern (Step B12).

  Thereafter, until the value of the number of deficient data P becomes 0 (No in Step B10), the difference between the positions of the two rotation detection images is not two pixels or more in the same manner as described above. With the image data, it is possible to supplement the shortage in the process in the previous half cycle.

  When the difference between the positions of the two rotation detection images is reversed (decreased or increased) from the change trend of the difference in the image data to be processed so far, that is, the situation where the CPU 10 has increased or decreased, the CPU 10 (Step B8, Yes), the number P of deficient data is calculated and set as P = N−M (Step B15), and the process for the image data for a half cycle is completed.

  In this way, in the second embodiment, the number of acquired image data (acquired image reference number N) is managed for each half cycle of the triangular wave pattern, and the acquired image data number N of image data is not output (recorded). Is supplemented in the half-cycle image data acquisition process of the next half-cycle, so that the vertical enlargement / reduction of the entire image representing the fingerprint pattern can be reduced, and a high-quality image can be generated.

  In the second embodiment, it has been described that the number of acquired image data in a half cycle may be insufficient for the half cycle acquired image reference number N. However, the half cycle acquired image reference number including an error in acquisition determination is described. The rotation detection pattern 30 in which the angle of the shaded portion of the triangular wave pattern and the triangular wave pattern width are increased may be used so that the image data of N + α is reliably output. As a result, the number of half-cycle acquired image data M always reaches the half-cycle acquired image reference number N within a half cycle. Note that after the half-cycle acquired image data number M reaches the half-cycle acquired image reference number N, image data may not be acquired until the half cycle ends (pattern inversion).

  In the first and second embodiments described above, the rotation detection patterns 30 and 32 attached to the transparent rotating roller 29 are formed by two patterns formed by repeating repeated diagonal lines. This pattern may be a vertical line (a line perpendicular to the axial direction of the transparent rotating roller 29).

  For example, FIG. 18 is a perspective view showing an external configuration of a transparent rotating roller 29 provided with a rotation detection pattern 34 having one pattern as a vertical line, and FIG. 19 is attached to the transparent rotating roller 29 shown in FIG. It is a figure which expands and shows the portion equivalent to pattern 34 for rotation detection in the shape of a plane. As shown in FIGS. 18 and 19, the apex of the triangular wave pattern and the vertical line pattern are arranged so as to contact each other, but the two patterns may be separated.

  Furthermore, it is good also as the rotation detection pattern 34 which has two vertical line patterns and arrange | positions the triangular wave pattern formed from the continuous diagonal line in it.

  For example, FIG. 20 is a perspective view showing an external configuration of a transparent rotating roller 29 provided with a rotation detection pattern 34 including two vertical line patterns, and FIG. 21 is attached to the transparent rotating roller 29 shown in FIG. It is a figure which expands and shows the portion equivalent to pattern 34 for rotation detection in the shape of a plane.

  In this way, even when the rotation detection pattern 34 shown in FIGS. 18 to 21 is attached to the transparent rotation roller 29, the fingerprint is obtained in the same manner as the half-cycle image data acquisition process in the first and second embodiments described above. An image representing the pattern can be generated.

  In the first and second embodiments described above, the half-cycle is defined as a range in which the valley portion (one oblique line) is read from the peak portion of the triangular wave pattern of the rotation detection patterns 30, 32, and 34. The image data determined as the half-cycle acquired image reference number N with respect to the cycle is output (recorded), but the image data may be output (recorded) in a unit different from the half cycle. For example, the same image data acquisition process as described above may be executed in units of any one of the double cycles with respect to the half cycle.

  Further, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention in the implementation stage. Further, the functions executed in the above-described embodiments may be combined as appropriate as possible. The above-described embodiments include various stages of the invention, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if several constituent requirements are deleted from all the constituent requirements shown in the embodiment, an effect can be obtained, so that a configuration from which the constituent requirements are deleted can be extracted as an invention.

1 is a block diagram showing a configuration of an electronic circuit of a mobile phone equipped with an image reading device according to an embodiment of the present invention. 1 is a diagram showing an external appearance of a mobile phone equipped with an image reading apparatus according to an embodiment of the present invention. The schematic block diagram (side sectional drawing) of the mechanism part of the fingerprint reading part 20 concerning embodiment of this invention. The perspective view which shows the external appearance of the transparent rotation roller 29 to which the pattern 30 for rotation detection in embodiment of this invention was attached | subjected. The figure which expand | deployed the part corresponded to the pattern 30 for rotation detection in embodiment of this invention in planar shape. The figure which shows the correspondence of the pattern 30 for rotation detection attached | subjected to the transparent rotation roller 29 in embodiment of this invention, and the image pick-up element of the one-dimensional image pick-up element 24. FIG. The flowchart for demonstrating the half-cycle image data acquisition process in 1st Embodiment of this invention. The figure which expands and shows the pattern 30 for rotation detection attached | subjected to the transparent rotation roller 29 in 1st Embodiment of this invention in planar shape. The figure which shows an example of the image for a rotation detection about the line for several in 1st Embodiment. The perspective view which shows the external appearance structure of the transparent rotation roller 29 in 1st Embodiment. The figure which expand | deploys and shows the part corresponded to the pattern 30 for rotation detection in 1st Embodiment planarly. The flowchart of the half-cycle image data acquisition process at the time of adding the rotation detection pattern 32 in 1st Embodiment. The perspective view which shows the external appearance of the transparent rotation roller 29 to which the pattern 32 for rotation detection in 1st Embodiment was attached | subjected. The figure which expand | deployed the part corresponded to the pattern 32 for rotation detection in 1st Embodiment planarly. The perspective view which shows the external appearance of the transparent rotation roller 29 to which the pattern 32 for rotation detection which has another shape in 1st Embodiment was attached | subjected. The figure which expand | deployed the part corresponded to the pattern 32 for rotation detection corresponding to FIG. The flowchart shown about the half-cycle image data acquisition process in 2nd Embodiment. The perspective view which shows the external appearance structure of the transparent rotation roller 29 concerning embodiment of this invention. The figure which expands and shows the part corresponded to the pattern 34 for rotation detection attached | subjected to the transparent rotation roller 29 shown in FIG. The perspective view which shows the external appearance structure of the transparent rotation roller 29 concerning embodiment of this invention. The figure which expands and shows the part corresponded to the pattern 34 for rotation detection attached | subjected to the transparent rotation roller 29 shown in FIG.

Explanation of symbols

    DESCRIPTION OF SYMBOLS 10 ... CPU, 12 ... Storage device, 14 ... RAM, 16 ... Call unit, 18 ... Display unit, 19 ... Key unit, 20 ... Fingerprint reading unit, 21 ... Light source, 22 ... Selfoc lens (lens optical system), 24 ... one-dimensional imaging device, 26 ... imaging control circuit, 27 ... A / D conversion circuit, 28 ... rotation detection sensor, 29 ... transparent rotating roller, 30, 32, 34 ... pattern for rotation detection.

Claims (2)

A transparent rotating roller having a hollow inside, a one-dimensional imaging device installed inside the transparent rotating roller, and an image for reading a fingerprint image captured by the one-dimensional imaging device as the finger is pressed against the transparent rotating roller An image reading apparatus having reading means,
The transparent rotating roller, Ru subjected over one round of the outer peripheral surface so that the two patterns straight portion is a triangular wave is continuously alternately become line symmetry with a constant angle with respect to the rotary roller shaft In addition, in order to determine the period, a line pattern parallel to the rotation roller axis is added to the apex of the peaks and valleys of the triangular wave,
The image reading means includes a center position detecting means for detecting a center position of an image corresponding to the two patterns read together with a fingerprint image by the one-dimensional image sensor, and a center position detected by the center position detecting means. An image reading apparatus comprising: a position correcting unit that corrects a position of a fingerprint image read by the one-dimensional image sensor based on the position. A judging means for judging whether or not images of the number of lines determined corresponding to the period determined by the triangular wave pattern are recorded;
When the number of lines of the recorded image does not reach the determined number of lines, the image read in the next cycle has means for compensating for the number of unreachable lines. The image reading apparatus according to claim 1.

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