JP2013130981A - Image acquisition device and biometric authentication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image acquisition device capable of preventing unevenness of brightness and decrease in contrast in imaging with plural light sources.SOLUTION: An area to be imaged where a subject is disposed and the subject can be imaged is divided into plural division areas. LEDs 2a, 2b and 2c for radiating light are disposed in the division areas, respectively. An imaging range 41 of an imaging element 4 is divided into plural division ranges 4a, 4b and 4c corresponding to the division areas, respectively. A portion of the subject disposed in each division area is imaged in a one of the division ranges 4a, 4b and 4c corresponding to the division areas. The control of the LEDs 2a, 2b and 2c is performed so as to turn on only one of the LEDs radiating light to a division area corresponding to a division range having a sensor outputting data indicating the amount of light received among sensors of the imaging element 4 and to turn off the others.

Description

  The present invention relates to an image acquisition device that illuminates a subject with a plurality of LEDs, and a biometric authentication device including the image acquisition device.

In recent years, in order to strengthen security protection, it has been proposed to attach or incorporate a biometric authentication device to various information devices such as mobile phones, smartphones, PDAs, tablets, notebook computers, desktop computers, and other computer systems.
As biometric information used in biometric authentication, information using an iris pattern of eyes, a fingerprint pattern, or a finger or hand vein pattern is known.

  Among these, when imaging the vein pattern of the finger, the vein is in the finger, so that near infrared rays that are permeable to the human body and are not easily transmitted through blood vessels (veins) are absorbed by hemoglobin. A light source is used. As the light source, an LED (light emitting diode) is used in consideration of power saving and downsizing. In addition, LED which outputs the light of the frequency range which becomes near-infrared though the wavelength range of the emitted light differs with LED is known.

Further, it is generally known that when an LED is used as a light source, the LED has high directivity characteristics, and therefore, the illuminance in a range exceeding a certain viewing angle (irradiation angle) becomes extremely dark.
For this reason, in order to ensure illuminance evenly over the entire image, it is necessary to arrange a plurality of LEDs according to their directivity characteristics.

  When photographing a living body using a plurality of LEDs, for example, a plurality of LEDs are simultaneously turned on to photograph one image. In addition, when photographing one range of the living body, the range is divided into a plurality of images, and each divided portion is imaged by illuminating with a different LED. A plurality of images may be combined to obtain a single image.

  However, in reducing the size of the biometric authentication device, in an imaging device for imaging a part of a living body as a subject, when an arrangement of an optical system that forms an image of the subject on an imaging element is considered, a plurality of In some cases, it is difficult to arrange the LEDs in an optimal arrangement for illumination of a living body.

  For example, a microlens array is used as a member of an optical system that is attached to an image sensor, and an LED that serves as a light source for illumination for miniaturization is disposed at opposite ends (for example, left and right ends) of the microlens array. It is assumed that the living body facing the microlens array is illuminated. In this case, since the LEDs are arranged on the left and right sides with a space therebetween, the left and right end portions of the microlens array become brighter, and the portion between these left and right end portions becomes darker.

  Therefore, when the horizontal line of each pixel of the image sensor is along the left-right direction, light is received from the sensors near the left and right ends of the microlens array, among the sensors of each pixel of the image sensor, according to the synchronization signal. At the timing of reading the charge indicating the amount, the brightness of the LED is lowered, and at the timing of reading the received light amount from the sensor near the center between the left and right sides of the macro lens array, the brightness of the LED is increased, thereby moving left and right. It has been proposed that even if an LED is used, there is no significant unevenness in luminance (see, for example, Patent Document 1).

JP 2010-49664 A

  By the way, it is difficult to eliminate uneven brightness even when a plurality of LEDs are arranged uniformly. For example, in order to eliminate the dark part, it is necessary to arrange a plurality of LEDs so that the light overlaps each other. In this case, when the illuminance necessary for the part illuminated by one LED of the subject is secured, In a portion where the light irradiation ranges of the respective LEDs overlap, the luminance may become too high, resulting in unevenness.

  In addition, since the living body to be illuminated is, for example, a finger and has a three-dimensional configuration, at the time of imaging, light that circulates from the outside of one LED finger, light reflected from the finger, and other LEDs There is a possibility that the light transmitted through the finger overlaps. In this case, in the image using the light transmitted through the finger for imaging, there is a possibility that the contrast is lowered due to the light not transmitted through the finger entering. In particular, it is conceivable that contrast is deteriorated by causing a plurality of LEDs to emit light simultaneously. This is because, by using a plurality of LEDs, the amount of light that circulates and reflects without passing through the finger is larger than that of a single LED, and these lights cause a deterioration in contrast.

Also in the invention of Patent Document 1, a plurality of LEDs are arranged uniformly in the vertical direction at the left and right ends of the microlens array, and there is a problem caused by using the plurality of LEDs as described above. To do.
In addition, in the method of performing imaging for each of a plurality of arranged LEDs and combining the captured portions, one LED can be used for one imaging, so that a plurality of LEDs can be used as described above. The problem that arises can be avoided by turning on simultaneously.
However, there is a problem that imaging takes time by performing imaging a plurality of times. Further, it may take time to combine a plurality of images into one image. For these reasons, when such a method is applied to an image acquisition apparatus for biometric authentication, there is a problem that the processing time from imaging of the biometric to the end of authentication becomes long.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image acquisition apparatus and a biometric authentication apparatus that can prevent uneven brightness and a decrease in contrast in imaging having a plurality of light sources. .

The present invention is arranged in a matrix form vertically and horizontally and includes a plurality of sensors for detecting the amount of received light, respectively,
An optical system for forming an image of the subject on the image sensor;
A plurality of light sources that irradiate the subject with light as illumination and each have a different light irradiation range;
A video signal based on an amount of electric charge corresponding to the amount of received light and sequentially output from each sensor of the image sensor in a predetermined order; and a control means for controlling the amount of light emitted from the light source,
An image acquisition device for acquiring an image obtained by imaging the subject,
The control means is based on the output timing of the charge from each sensor of the image sensor and corresponds to the light irradiation range of each light source so that the emitted light amount of each light source changes individually. The amount of emitted light is controlled.

  The light source is preferably an LED.

The video signal input from the image sensor to the control means is synchronized with the signal in which the amount of the charges sequentially output from each sensor is arranged in the output order and the output timing of the charges from each sensor. It consists of an output sync signal,
Preferably, the control means individually controls the amount of light emitted from each light source based on the synchronization signal.

The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. Output a horizontal sync signal,
It is preferable that the control means individually controls the amount of light emitted from each light source based on the lateral direction synchronization signal.

The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. A horizontal sync signal,
Each time the switch is turned on, the sensor that outputs the charges in accordance with the horizontal arrangement order of the sensors arranged in a horizontal row specified by the horizontal synchronization signal outputs an individual synchronization signal that sequentially shifts to the next. And
Preferably, the control means individually controls the amount of light emitted from each light source based on the lateral direction synchronization signal and the individual synchronization signal.

Each light source is arranged corresponding to a plurality of divided regions obtained by dividing the imaged region on which the subject image can be formed on the image sensor when the subject is installed. The divided areas are arranged to be included in the light irradiation range,
The imaging device includes the sensor, and when an imaging range that can be imaged includes the subject in the divided area, an image of a portion of the subject in the divided area is formed by the optical system. Divided into a plurality of divided ranges corresponding to each divided area,
The control unit includes the sensor in a state where the sensor in the divided state of the image sensor outputs the charge by sequentially outputting the charges in a predetermined order by the sensor of the image sensor. As the divided areas corresponding to the ranges change, it is preferable to individually control the amount of light emitted from each light source that sets each divided area as a main light irradiation range.

The image pickup device is a video signal composed of a signal in which the amount of charges sequentially output from each sensor is arranged in an output order and a synchronization signal output in synchronization with the output order of the charges from each sensor. Output
The control means determines the divided region corresponding to the divided range where the sensor in a state where the charge of the image sensor is output based on a synchronization signal output from the image sensor, and As the divided areas determined based on the synchronization signal change, it is preferable to individually control the amount of light emitted from each light source having each divided area as a main light irradiation range.

The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. Output a horizontal sync signal,
The control means sets each division range of the imaging range of the imaging device as a range of the number of times the horizontal direction synchronization signal is turned on, and the set division ranges are arranged in a row in the horizontal direction. It is preferable that the sensor comprises a range of a plurality of rows that are continuous in the vertical direction of the sensor.

The plurality of light sources are arranged side by side along the vertical columns of the sensors arranged in a matrix in the vertical and horizontal directions of the imaging device,
In response to the horizontal direction synchronization signal, the control means sequentially turns on the plurality of light sources arranged along the vertical columns of the sensors in the order along the vertical columns or is larger than other light sources. It is preferable to control the amount of emitted light.

The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. A horizontal sync signal,
Each time the switch is turned on, the sensor that outputs the charges in accordance with the horizontal arrangement order of the sensors arranged in a horizontal row specified by the horizontal synchronization signal outputs an individual synchronization signal that sequentially shifts to the next. And
The control means sets each division range of the imaging range of the imaging element as a range of the number of times the individual synchronization signal is turned on, and the set division range is a sensor arranged in a row in a vertical direction. It preferably consists of a range of a plurality of rows that are continuous in the horizontal direction.

The plurality of light sources are arranged side by side along a horizontal row of the sensors arranged in a matrix in the vertical and horizontal directions of the imaging device,
In response to the individual synchronization signal, the control means sequentially turns on or emits a plurality of the light sources arranged along a horizontal row of the sensors in an order along the horizontal row or larger than other light sources. It is preferable to repeat the control so as to obtain a light amount every time the horizontal synchronization signal is output.

  The control unit includes the sensor in a state where the sensor in the divided state of the image sensor outputs the charge by sequentially outputting the charges in a predetermined order by the sensor of the image sensor. It is preferable to control so that each light source having each divided region as a main light irradiation range is turned on and off in turn as the divided region corresponding to the range changes.

  The control unit includes the sensor in a state where the sensor in the divided state of the image sensor outputs the charge by sequentially outputting the charges in a predetermined order by the sensor of the image sensor. As the divided region corresponding to the range changes, the light source having the divided region corresponding to the divided range corresponding to the certain divided range having the light output range has the largest amount of emitted light as the divided region changes. It is preferable to control.

Analyzing means for analyzing the brightness and contrast of the acquired image;
The said control means adjusts the contrast of the image acquired by controlling the timing of lighting and extinction of each light source and / or the emitted light quantity of each light source based on the analysis result of the said analysis means. The image acquisition device according to any one of claims 1 to 13.

  The biometric authentication apparatus of the present invention includes any one of the above-described image acquisition apparatuses, and performs personal authentication by collating biometric patterns extracted from image data captured by the image acquisition apparatus.

  According to the present invention, when illuminating a subject with a plurality of light sources substantially evenly, it is possible to reduce power and suppress uneven brightness without simultaneously turning on all the light sources with a predetermined amount of light. .

  Here, in the image sensor, charges indicating the light quantity are not output simultaneously from a large number of sensors arranged in a matrix, but charges are output from each sensor in turn, and the charges are output from each sensor. There will be a time difference in the timing to be performed. Therefore, the timing at which each sensor detects the amount of received light also has a time difference, and the light from the light source is irradiated through the subject to the sensor at the timing at which the amount of received light is detected (immediately before the timing for outputting the charge). If this is the case, there is no problem even if light is not input to a sensor that is not at the timing of detecting the amount of received light.

  In addition, a sensor in an arbitrary range can be illuminated with an appropriate amount of light by turning on / off a plurality of light sources having different irradiation ranges or adjusting an increase / decrease in the amount of emitted light. Therefore, by controlling the emitted light quantity of each light source individually according to the output timing of the charge of each sensor and corresponding to the light emission range, it is not necessary to turn on all the light sources simultaneously with substantially the same emitted light quantity. Also, imaging can be performed in a state in which substantially the same amount of light necessary for the entire image is secured.

Thereby, the power consumption can be reduced as compared with the case where all the light sources are simultaneously turned on with substantially the same light amount during the imaging time.
In addition, when the LED is used as the light source, the directivity of the light irradiation range is high. Therefore, when a plurality of LEDs are simultaneously turned on with the same amount of light, the portion where the light irradiation range of each LED does not overlap. Therefore, there is a difference in brightness, and uneven brightness is likely to occur, and contrast may be deteriorated.However, by controlling the amount of light individually for each light source according to the charge output timing of each sensor Therefore, it is possible to suppress uneven brightness of an image that is excellent in sampling and to improve contrast.

  The charge output timing of each sensor can be obtained from a signal in which the amount of charge output from each sensor output as a video signal is arranged in the order of output. That is, as the signal, for example, a signal in which a peak of height corresponding to the amount of electric charge of each sensor is periodically output, or a value obtained by digitally converting the peak height is sequentially output. Therefore, the output timing of charges from each sensor can be obtained from the output of these peaks and values. For example, by counting the number of the peak after the peak output starts, the sensor at the timing of outputting the charge can be obtained.

  Further, the video signal includes a synchronization signal, and the sensor outputting the charge can be specified by the synchronization signal. In addition, as a synchronizing signal, a horizontal direction synchronous vibration (HREF signal) and an individual synchronizing signal (Pixel Clock signal) can be used.

  As described above, even when a plurality of LEDs are used for illumination of a subject, all LEDs are not lit at a predetermined light amount at the same time. It is possible to raise and lower. At this time, it is possible to turn on and turn off the LEDs one by one, and it is possible to solve the problem when a plurality of LEDs having high directivities are turned on simultaneously with a predetermined light amount.

  In addition, even in a configuration in which each part of the subject is illuminated in order, it is only necessary to capture one image for acquisition of an image, and the processing time becomes longer due to the imaging time and the synthesis of multiple images. Can be prevented. That is, in order to solve the problem when a plurality of LEDs are turned on simultaneously, for example, even if each LED is turned on one by one, it is possible to prevent the imaging time from becoming longer.

  In addition, it is assumed that a subject area is set up, and an imaging area where the installed subject can be imaged is divided into a plurality of divided areas, each divided area is illuminated by each LED, and the imaging range of the imaging element is further divided into the divided areas. When the amount of charge indicating the amount of light received is output from each sensor on the image sensor, the divided region corresponding to the divided range including the sensor that is outputting the charge is the light irradiation range. It is possible to turn on only the LEDs included in the LED, increase the amount of emitted light, turn off the other LEDs, or decrease the amount of emitted light, so that multiple LEDs are consumed compared to when all LEDs are lit during the imaging time. Electric power can be reduced and power can be saved. That is, for example, when the LEDs are turned on one by one during image capturing, the power consumption is basically the same as when one LED is lit during the image capturing time, thus saving power. Can be planned.

In addition, when each divided region is illuminated by one LED, the central portion of the irradiation range is basically brighter than the peripheral portion, depending on the lens provided in the LED.
Thereby, also in the division range, the portion corresponding to the central portion of the divided region becomes brighter than the portion corresponding to the peripheral portion. In this case, the peripheral portion of the divided region is also lit by an LED having the adjacent divided region as an irradiation range (adjacent LED), so that the peripheral portion is brightened by the irradiation of light from the adjacent region.

  At this time, if the adjacent LED also has the same light amount as the LED that mainly irradiates light, there is a possibility that the peripheral portion becomes brighter than the central portion of the divided region. In addition, the amount of light that is not necessarily required for imaging increases due to reflection of light from each light source, which may lead to a decrease in contrast. Therefore, since the emitted light amount of each LED can be individually controlled, the main LED corresponding to a certain range of the sensor outputting the charge is set to a high emitted light amount, and the adjacent LED is controlled to a lower emitted light amount. As a result, unevenness in luminance can be reduced and contrast can be improved.

  In addition, a division range is set based on the range of the number of times the synchronization signal that is output when the charge indicating the amount of light received from each sensor of the image sensor is output, and is specified by the number of times the synchronization signal is turned on. Only the LEDs that irradiate light to the divided areas corresponding to the divided ranges can be controlled to turn on or increase the amount of emitted light. In other words, the LED can be turned on and off, and the amount of emitted light can be increased or decreased based on the synchronization signal synchronized with the output of electric charges from each sensor of the image sensor, thereby facilitating control.

  In addition, the arrangement of the LEDs is, for example, an arrangement arranged in a direction along a vertical column of sensors arranged in a matrix in the vertical and horizontal directions, or an arrangement arranged in a direction along the horizontal row of sensors. As long as the LEDs can be turned on and off sequentially in the order of arrangement, the structure of the image acquisition device can be simplified.

  Also, analyze the brightness and contrast of the image once acquired, and adjust the emission light amount when each LED is turned on, the timing of increase / decrease of the emitted light amount, and the lighting and extinguishing timing of each LED based on the analysis result By doing so, image data with more appropriate contrast can be obtained.

  Note that the amount of charge corresponding to the amount of light received by each sensor is accumulated from the state where the charge is cleared by the output of the previous charge to the next output of the charge. Before the output of the charge of the sensor included in the light, it is necessary that light is irradiated from the LED to the divided range via the subject. In addition, for example, when the light source is turned on or the amount of emitted light is increased in accordance with the sensor charge output timing, there is a time lag, and the lighting or emitted light amount The increase is delayed. Therefore, it is preferable to determine the actual timing of turning on and off the LED and the timing of changing the amount of emitted light by analyzing the luminance and contrast of the output video signal.

  From the above, the image acquisition device can be suitably used as an image acquisition device of a biometric recognition device, and can be particularly suitably used for an image acquisition device using a finger vein pattern for authentication.

1 is a schematic diagram illustrating an image acquisition device according to a first embodiment of the present invention. Relationship between the arrangement direction of sensors that sequentially output charges based on the synchronization signal on the image sensor of the image acquisition device and the divided range on the image sensor on which the image of the portion of the subject illuminated by each LED is formed It is drawing which shows. It is a timing chart which shows the timing of each synchronizing signal, the division range on the image pick-up element in which the image of the part illuminated to each LED of a to-be-photographed object is imaged, and the timing which each LED lights. It is a block diagram which shows the control system of the said image acquisition apparatus. It is the schematic which shows the more concrete structure of the optical system of the said image acquisition apparatus. It is a block diagram which shows a biometrics apparatus provided with the said image acquisition apparatus. It is the schematic which shows the image acquisition apparatus of 2nd Embodiment. Relationship between the arrangement direction of sensors that sequentially output charges based on the synchronization signal on the image sensor in the third embodiment and the divided range on the image sensor on which the image of the portion illuminated by each LED of the subject is formed It is drawing which shows. 12 is a timing chart showing the timing of each synchronization signal, the divided range on the image sensor on which the image of the portion individually illuminated on each LED of the subject is formed, and the timing when each LED is lit in the third embodiment. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the image acquisition apparatus according to the first embodiment includes a plurality of LEDs 2a, 2b, and 2c that irradiate a subject (for example, a specific finger) 1 that is a living body, and an image of a finger vein. The lens 3 as an optical system that forms an image on the image sensor 4 to be described later, the image sensor 4 and the image sensor 4 are controlled to input a video signal, and the LEDs 2a, 2b, and 2c are turned on. And a controller 8 (illustrated in FIG. 4) for controlling the light extinction and the amount of emitted light.

In addition, in FIG. 1, although the light irradiated from each LED2a, 2b, 2c is illustrated mutually as arrangement | positioning of LED2a, 2b, 2c, as below-mentioned,
The pattern arrange | positioned so that the light irradiated from each LED2a, 2b, 2c may cross | intersect may be sufficient. Moreover, although several LED2a, 2b, 2c is made into three in this embodiment, it may be two or may be four or more.

  Each of the LEDs 2a, 2b, and 2c divides an imaging area where the subject 1 is arranged and an image of the subject 1 can be formed on the imaging element 4 by the lens 3 into three divided areas, and is arranged in the imaging area. A portion of each subject that is arranged in each divided area is illuminated by one LED 2a, 2b, and 2c. The three LEDs 2a, 2b, and 2c are arranged in a line corresponding to the output order of charges indicating the amount of light from the matrix sensor constituting the imaging device 4 as described later.

  The LEDs 2a, 2b, and 2c have high directivity, but output diffused light. The portions arranged in each divided area of the subject 1 have a necessary and sufficient amount of light by the single LEDs 2a, 2b, and 2c. The types of LEDs 2a, 2b, and 2c, the amount of light, and the distance from the subject 1 are set so as to be illuminated. At this time, since the LEDs 2a, 2b, and 2c are sequentially turned on one by one as will be described later, the light amount of the overlapping portions of the light irradiation ranges of the respective LEDs 2a, 2b, and 2c is not considered, The irradiation range is set so that the entire portion corresponding to each divided area of the subject 1 is sufficiently illuminated.

  The lens 3 is, for example, a lens unit composed of a plurality of lenses, and is set so as to form an image of a portion of the subject 1 that is imaged in an imaging range 41 (to be described later) that can be imaged on the imaging device 4. Yes.

  The image sensor 4 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor, and the sensors of each pixel are arranged vertically and horizontally in a matrix. When a charge indicating the amount of light received from each sensor is output, the charges are sequentially output from each sensor based on the synchronization signal, and the output of the charges from each sensor is output. The output of charges for one image is started by a Vsync signal (vertical synchronization signal) output in synchronization with a Pixel Clock signal (individual synchronization signal) corresponding to the order.

  When this Vsync signal is output from the image sensor, the first HREF signal (horizontal sync signal: horizontal sync signal) is output, and the top (top) horizontal row (the top in the horizontal direction) in the vertical (vertical) direction. Charges indicating the amount of received light are sequentially output from each sensor along one direction (for example, from left to right) for each Pixel Clock signal from the sensors in the upper row). Further, the sensor moves to one lower row of sensors based on the next HREF signal, and charges are output from each sensor again in one direction for each Pixel Clock signal from the left side. Thereafter, for each HREF signal, a shift is made to the next lower row to output charges.

  In this embodiment, the irradiation positions of the plurality of LEDs 2a, 2b, 2c are arranged along the vertical direction perpendicular to the horizontal direction of the sensors arranged vertically and horizontally in the matrix form of the image sensor 4. A plurality of LEDs 2a, 2b, 2c are arranged side by side in a vertical row. That is, the area to be imaged in which the subject 1 is installed is divided into three divided areas along the vertical alignment direction of the sensors of the image sensor 4, and one LED 2a, 2b, 2c is provided in each of the divided areas. Each LED 2a, 2b, 2c is arranged side by side so that light may be irradiated, respectively.

As shown in FIG. 2, the first LED 2a irradiates light (mainly light in a frequency range corresponding to the near infrared) to the first divided region of the imaging region where the subject 1 is installed. An image of the portion of the subject 1 that falls within the divided area where the second LED 2 a is irradiated with light is formed as an image A on the divided range 4 a of the image sensor 4 by the lens 3. Similarly, the second LED 2b irradiates light to the second divided region along the vertical direction of the sensor of the above-described imaging element 4 in the imaged region, and irradiates light to the second LED 2b. The image of the portion of the subject 1 that falls within the divided area is formed as an image B by the lens 3 in the divided range 4 b of the image sensor 4. The third LED 2c irradiates light to the third divided portion along the longitudinal direction of the sensor of the image pickup device 4 in the image pickup region, and the third LED 2c is irradiated with light in the divided region. The image of the portion of the subject 1 in the image is formed as an image C in the divided range 4 c of the image sensor 4 by the lens 3.
Each of the divided ranges 4a, 4b, and 4c is a range obtained by dividing the imaging range 41 in which the subject 1 of the imaging device 4 can be imaged in accordance with the location where the portion of the subject arranged in each divided region is imaged. The divided areas 4a, 4b, and 4c correspond to the divided areas, and the image of the portion of the subject in each divided area is formed on the divided areas 4a, 4b, and 4c of the corresponding image sensor 4 by the lens 3. To do.

  The divided ranges 4a, 4b, and 4c of the image sensor 4 are arranged side by side in the vertical direction (vertical direction) of the above-described sensor. The output direction of the charge from each sensor is indicated by a zigzag arrow, and from the above-mentioned synchronization signal, one row is output in the horizontal direction, then one is moved in the vertical direction, and one row is output in the horizontal direction again.

  Therefore, when the image pickup device 4 outputs one image as a video signal, the image corresponding to the divided range 4b is output after the image corresponding to the divided range 4a is first output, and further divided thereafter. An image corresponding to the range 4c is output.

  When charges are output from each sensor in the divided range 4a, if the LED 2a that irradiates light to the portion of the subject 1 in the divided region corresponding to the divided range 4a is lit, the other LEDs 2b and 2c When the electric charge is output from each sensor in the divided range 4b without having to be lit, the LED 2b that irradiates the subject 1 in the divided area corresponding to the divided range 4b is turned on. For example, when the other LEDs 2a and 2c do not need to be lit and the electric charge is output from each sensor in the divided range 4c. If the LED 2c that irradiates light to the portion of the subject 1 in the divided area corresponding to the divided range 4c is lit, it is not necessary that the other LEDs 2a and LED 2b are lit.

  In this image acquisition device, as shown in the timing chart of FIG. 3, the LEDs 2a, 2b, and 2c are illuminated in accordance with the output timing of the charges from the sensors of the pixels of the imaging elements 4.

  As shown in FIG. 3, during one imaging of the imaging range of the subject 1, the amount of light received from each of the vertical and horizontal sensors of the imaging range 41 of the imaging device 4 while one Vsync signal is output. The charge corresponding to is output. At this time, for each HREF signal, the charge is output from the first sensor in the horizontal row as described above, and the output source moves to the sensor in the lower horizontal row for each HREF signal. It is supposed to be.

  At this time, the control unit 8 (illustrated in FIG. 4) for controlling the turning on / off of the LEDs 2a, 2b, and 2c and the amount of emitted light outputs the LEDs 2a, 2b. 2c is controlled to be turned on and off. For example, when the number of rows in the effective range of the image sensor 4 is 300, that is, when the number of vertical pixels is 300, the HREF signal is output from the first time to the 300th time, for example.

  At this time, for example, the LED 2a has a subject 1 on which an image is formed in the divided range 4a of the image sensor 4 which is the range of the first to 100th horizontal rows as the range of the number of times the HREF signal is turned on. The LED 2b emits necessary and sufficient light in the range (first divided area), and the LED 2b is the range of the horizontal row from the 101st to the 200th as the range of the number of times the HREF signal is turned on. Necessary and sufficient light is irradiated to the range of the subject 1 on which the image is formed in the divided range 4b, and the LED 2c is in a range of horizontal rows from the 201st to the 300th as a range of the number of times the HREF signal is turned on. Necessary and sufficient light is irradiated to the portion of the subject 1 imaged in the divided range 4 c of a certain image sensor 4. That is, the division ranges 4a, 4b, and 4c are set as a range of the number of times that the HREF signal as the synchronization signal is turned on.

Here, in order to irradiate necessary and sufficient light, the respective divided ranges 4a, 4b, and 4c of the above-described imaging element 4 of the subject 1 are within the range of the irradiation angle of the diffused light emitted from the LEDs 2a, 2b, and 2c. It is necessary to include all the portions to be imaged (portions within each divided region).
When outputting the charge indicating the amount of light of each pixel, that is, the luminance from the image sensor 4, when the HREF signal indicating the start of the output of the horizontal row of pixels is output as described above, the charge is output from the first horizontal row of sensors. Will be.

Therefore, imaging of the range of the subject irradiated with light on the LED 2a is performed from the output of the first HREF signal to immediately before the output of the 101st HREF signal.
In addition, since the output from each sensor in the horizontal row is performed every time the Pixel Clock signal is output, for example, when 600 sensors are arranged in a horizontal row, the subject 1 to which the LED 2a is irradiated with light is described above. The imaging of the imaging range is performed from the output of the first HREF signal to the output of 600 Pixel Clocks after the output of the 100th HREF signal.

  The LED 2a is turned on from the output of the first HREF signal to the output of the 100th HREF signal plus 600 pixel clock signals (immediately before the output of the 101st HREF signal). That is, the LED 2a is turned on when the HREF signal is output for the first time, and the LED 2a is turned off immediately before the output of the 101st HREF signal (approximately when the HREF signal is output for the 101st time).

  The LED 2b is turned on when the 101st HREF signal is output, and the LED 2b is turned off when the 201st HREF signal is output (or immediately before). The LED 2c is turned on when the 201st HREF signal is output, and the LED 2c is turned off when 600 pixel clocks are output after the 300th HREF signal is output (when the HREF signal is output for the 301st time). .

Thereby, in the division range 4a of the image element 4 described above, the image portion 5a (6a) of the final image (captured image) 5 (6) is captured, and in the division range 4b, the final image portion 5a (6a) is captured. The image portion 5b (6b) of the single image 5 (6) is captured, and the image portion 5c (6c) of the final single image 5 (6) is captured in the divided range 4c. . Note that the image 5 is obtained by aligning the length direction of the finger as the subject 1 along the horizontal direction of the arrangement of the sensors of the image sensor 4, and the image 6 is the image of the length direction of the finger as the subject 1. 4 along the vertical direction of the arrangement of the four sensors.
Also, a vein in the finger as the subject 1 is imaged.

  Each LED 2a, 2b, 2c can be controlled to be turned on and off independently by the control means, and each LED 2a, 2b, 2c can change the amount of emitted light independently. Therefore, the LEDs 2a, 2b, and 2c are not sequentially turned on and turned off, but the emitted light amount is sequentially increased and decreased as described later, and the emitted light amounts are different between adjacent LEDs 2a, 2b, and 2c, but the lighting time is partially or entirely overlapped. Such control may be performed.

  Each sensor of the image sensor 4 accumulates charges based on the amount of received light immediately before outputting charges. For example, the charges are cleared when the charges are output before the current charge is output. The charge is accumulated based on the amount of received light thereafter, and the accumulated charge is output. Therefore, it is necessary to irradiate the light of the LEDs 2a, 2b, and 2c before the charge is output, and the timing of turning on and off the LEDs 2a, 2b, and 2c or increasing / decreasing the amount of emitted light is based on the synchronization signal described above. Although it is based, in practice, it is necessary to make the timing slightly faster than the output timing of each of the synchronization signals described above.

  That is, as described above, for example, when one of the LEDs 2a, 2b, and 2c is lit at the same time when a charge is output from the first cell in the divided ranges 4a, 4b, and 4c when a predetermined HREF signal is output. In the cell that outputs charge first, the charge is output in a state where no light is input based on the illumination of the LEDs 2a, 2b, and 2c. Therefore, by turning on and off the LEDs 2a, 2b, and 2c based on the image analysis of the captured image, which will be described later, or performing feedback control of the timing of increasing / decreasing the amount of emitted light, the LEDs 2a, 2b, and 2c are turned on / off with respect to the timing of the synchronization signal, Increasing / decreasing the amount of emitted light is made more suitable for image acquisition.

  With reference to the block diagram of the control system of the imaging acquisition apparatus in FIG. 4, control of LED lighting (increase in the amount of emitted light) will be described.

The imaging acquisition device includes, for example, the above-described imaging element 4 that is a CMOS image sensor chip, a plurality of LEDs 2a, 2b, and 2c that illuminate a subject in the imaging area as described above, the imaging element 4, A control unit (imaging control and LED control) 8 that controls the LEDs 2a, 2b, and 2c, and an analysis unit 10 that analyzes the captured image and feeds back an analysis result to the next control of the LEDs 2a, 2b, and 2c. .
For example, a method of changing the amount of emitted light from the drive circuits of the LEDs 2a, 2b, and 2c may be a method such as a method of changing a resistance value or a PWM control of changing a pulse width with a pulse power supply.

  In addition, the image acquisition device or a host device (smartphone, tablet, personal computer, computer system, etc.) to which the image acquisition device is connected has contrast and brightness of the captured image from the image sensor (corresponding to the amount of charge indicating the amount of received light). The image analysis program functions as the analysis unit 10 that operates. Moreover, the analysis part 10 may be comprised by the processor etc. which can execute image analysis programs, such as a one-chip microcomputer incorporated in the image acquisition apparatus.

  The analysis unit 10 analyzes the luminance of each pixel of the data of the captured image 9 by a known statistical process. For example, the captured image is divided after roughly dividing the image according to the difference in brightness such as the brightness of the part where the subject is not shown in the image, the brightness of the part where the subject has no veins, the brightness of the part where the subject has veins, etc. Whether the brightness of the data 9 is high or low is determined by the brightness of the image portions 5a, 5b, 5c (6a, 6b, 6c) corresponding to the respective LEDs 2a, 2b, 2c. Further, it is determined whether the contrast is high or low based on the luminance distribution of the image portions 5a, 5b, 5c (6a, 6b, 6c).

  Based on this, when the luminance of the image portion 5a corresponding to the sensor portion that outputs charges in an earlier order, for example, is low, the lighting timing of the LED 2a and the increase timing of the emitted light amount are controlled to be accelerated. On the contrary, by this control, when the brightness of the portion corresponding to the sensor portion that outputs charges in the earlier order of the image portion 5a becomes too bright, the timing of turning on the LED 2a and the timing of increasing the amount of emitted light are delayed. To control. Such control is also performed on the image portions 2b and 2c.

  Further, for example, when the luminance of the portion corresponding to the sensor portion that outputs charges in the last order of the image portion 5a is high, the timing for turning off the LED 2a and the timing for reducing the amount of emitted light are controlled. On the other hand, when the brightness of the portion corresponding to the sensor portion that outputs charges in the last order of the image portion 5a becomes too dark due to this control, the lighting timing of the LED 2a and the increase timing of the emitted light amount are delayed. Control to do. Such control is also performed on the image portions 2b and 2c.

  That is, when the contrast and brightness of the boundary portions of the image portions 5a, 5b and 5c of the image 5 are low, the LEDs 2a, 2b and 2b corresponding to the synchronization signals of the LEDs 2a, 2b and 2c, here, the HREF signal and the Pixel Clock signal. , 2c point lights and extinguishing timings are controlled so that the contrast and brightness of the boundary portions of the image portions 5a, 5b, 5c can be improved.

  In addition, when the overall brightness of the image portion 5a is too low, control is performed to increase the amount of light emitted from the LED 2a. When the brightness is too high, control is performed to decrease the amount of light emitted from the LED 2a, and when the brightness of the image portion 5b is low. Control is performed to increase the amount of light emitted from the LED 2b, control is performed to decrease the amount of light emitted from the LED 2b when the luminance of the image portion 5b is too high, and control is performed to increase the amount of light emitted from the LED 2c when the luminance of the image portion 5c is low. When the brightness of the image portion 5c is too high, control is performed so as to reduce the amount of light emitted from the LED 2c.

  Also, for example, if the light that does not pass through the subject 1 is reflected or circulated and input to the image sensor 4 with respect to the light that passes through the subject 1, the contrast of the image portion 5a is reduced. Is controlled so as to decrease the amount of light emitted from the LED 2a, and is controlled so as to decrease the amount of light emitted from the LED 2b when the contrast of the image portion 5b is low, and decreases the amount of light emitted from the LED 2c when the contrast of the image portion 5c is low. To control.

  In the image pickup device 4, when the power is turned on, a video signal for one image is repeatedly output every time a Vsync signal is periodically output, and so-called shutter is pressed, that is, the control unit 8 At the timing when the image acquisition control is performed, for example, one image of the video signal whose output is started simultaneously with the immediately following Vsync signal is stored.

  Therefore, the analysis unit 10 analyzes the video signal for each image repeatedly output from when the image pickup device 4 is turned on until the video signal for one image is stored. Based on the above, it is possible to adjust the amount of emitted light when the LEDs 2a, 2b, 2c are turned on, the timing of turning on / off, the timing of increase / decrease of the amount of emitted light, and the like.

  It should be noted that the above-described image analysis and LED control change accordingly may be performed every time the subject 1 is imaged, or may be periodically performed every predetermined number of times, and after being performed once. This may be performed only when there is an instruction, or may be performed once before shipment of the image acquisition apparatus.

  In the first embodiment, the LEDs 2a, 2b, and 2c are basically not lit at the same time. Therefore, when the contrast is reduced by the light that does not pass through the subject as described above, the cause is the lit LED 2a. , 2b, 2c, the amount of light emitted from the lit LEDs 2a, 2b, 2c is reduced. In addition, the brightness of the LEDs 2a, 2b, and 2c can be adjusted so that the brightness and contrast of the image portions 5a, 5b, and 5c are approximated.

  In such an image acquisition device, each LED 2a, 2b, 2c is not lit at the same time, and each divided range 4a of the imaging range 41, which is a sensor unit 7 composed of sensors arranged in a matrix of image elements 4, is provided. , 4b, and 4c sequentially output charges indicating luminance, and the LEDs 2a, 2b, and 2c are turned on and off one by one. Therefore, it is possible to obtain image data by one imaging while preventing adverse effects caused by the plurality of LEDs 2a, 2b, and 2c being simultaneously turned on.

That is, it is possible to prevent an adverse effect caused by lighting of the plurality of LEDs 2a, 2b, and 2c without increasing the processing time due to the number of times image data is captured and the combination of the plurality of image data.
Further, as an adverse effect of simultaneously lighting the plurality of LEDs 2a, 2b, and 2c, if the amount of light emitted from the plurality of LEDs 2a, 2b, and 2c is increased in order to increase the brightness of the image data, each of the LEDs 2a, 2b, and 2c A portion with a high luminance occurs in the overlapping area, and it is difficult to adjust the luminance of each LED 2a, 2b, 2c, and it is difficult to illuminate the entire imaging range of the subject 1 without unevenness.

  On the other hand, in this embodiment, there is only one LED 2a, 2b, 2c that is lit in each period, and even if the emitted light quantity of the LEDs 2a, 2b, 2c is increased to adjust the brightness of the image data, There is no problem in relation to the other LEDs 2a, 2b, 2c, and the luminance of each LED 2a, 2b, 2c can be changed relatively freely for adjusting the images 5, 6.

  Further, as an adverse effect of simultaneously lighting the plurality of LEDs 2a, 2b, 2c, the light transmitted through the subject to image the vein of the subject 1 (finger) of each LED 2a, 2b, 2c and the other LEDs 2a, 2b, 2c, When the light that has circulated around the outside of the finger as the subject 1 of 2c or the reflected light is simultaneously input to the image pickup device 4, the contrast is lowered. On the other hand, in this embodiment, there is no LED 2a, 2b, 2c that is lit at the same time, and only one LED 2a, 2b, 2c is lit, so the contrast is lowered by the other LEDs 2a, 2b, 2c. Can be prevented.

  Thereby, it is possible to easily make the brightness and contrast of image data obtained by one imaging appropriate.

  In addition, even when a plurality of LEDs 2a, 2b, and 2c are used, each LED 2a, 2b, and 2c is turned on and off one by one during one imaging time, so that an actually required one-time imaging is performed. The power is almost the same as the power required to light one LED 2a, 2b, 2c.

  Therefore, power consumption can be reduced as compared with the case where a plurality of LEDs 2a, 2b, and 2c are turned on simultaneously. Or, when the same power consumption is used as when all the LEDs 2a, 2b, 2c are turned on simultaneously during one imaging, the amount of power consumed to turn on the LEDs 2a, 2b, 2c can be increased. Brighter illumination is possible.

  When this image acquisition device is connected to a personal computer or the like as a host device, there is a possibility that a USB that is a general-purpose serial bus is generally used. In USB, not only data communication but also power supply from a host device is possible, and an electronic device can be driven without using an AC adapter or the like. However, there is a limit to the power that can be supplied by USB. For example, in an image acquisition device including a plurality of LEDs 2a, 2b, and 2c, when all the LEDs 2a, 2b, and 2c are turned on simultaneously, the LEDs 2a, 2b, and 2c There is a limit to the power that can be supplied.

  In this embodiment, since only one LED 2a, 2b, 2c is lit one by one, even if the power supplied to each LED 2a, 2b, 2c is increased, the plurality of LEDs 2a, 2b, 2c are all lit simultaneously. There is a high possibility of reducing power consumption. Therefore, even in an environment where the amount of power used is limited as described above, it is possible to sufficiently ensure the power supplied to each LED 2a, 2b, 2c.

  Here, in the first embodiment described above, the LEDs 2a, 2b, and 2c are turned on one by one. For example, when illuminating each divided area, the LEDs 2a, 2b, and Although it depends on the illumination lens provided in 2c, the peripheral portion may be darker than the central portion even within a predetermined light irradiation range. In this case, in addition to the LEDs 2a, 2b, and 2c corresponding to the divided regions, the peripheral portions can be prevented from being darkened by irradiating the LEDs 2a, 2b, and 2c that illuminate the adjacent divided regions with a low amount of emitted light. .

In this case, for example, when the divided area corresponding to the first LED 2a is illuminated by turning on the LED 2a, the LED 2b is lit with an emitted light quantity lower than the emitted light quantity of the LED 2a, and the next divided area is illuminated with the LED 2b. The amount of emitted light from the LED 2b is increased, and at this time, the amount of emitted light is decreased without turning off the LED 2a. At this time, the LED 2c is lit with an emitted light amount lower than that of the LED 2b.
Next, it is very good to increase the light quantity of the LED 2c, turn off the LED 2a, and lower the emitted light quantity of the LED 2b at the timing of illuminating the divided area corresponding to the LED 2c.

  In this case, a plurality of LEDs 2a, 2b, and 2c are lit simultaneously, but this corresponds to a divided area that is separated from another divided area to be illuminated (divided area being imaged) with another divided area interposed therebetween. The LEDs 2a, 2b, 2c to be turned off and the LEDs 2a, 2b, 2c in the divided areas adjacent to the main divided area are turned on with the amount of emitted light lowered, so that the influence of the LEDs 2a, 2b, 2c that are turned on simultaneously is suppressed. be able to. As a result, it is possible to suppress luminance unevenness of an image to be captured while suppressing a decrease in contrast.

  In addition, the emitted light quantity of each LED 2a, 2b, 2c may be controlled in two steps, for example, high and low, or may be controlled in three steps or more, and the emitted light amount is controlled step by step. Instead of this, the height may be controlled steplessly.

  Further, in contrast to a divided area having divided areas adjacent to each other in the front and rear, the center of the irradiation range of the LEDs 2a, 2b, and 2c is divided in the divided area at the end when there is only a divided area adjacent to one side. You may make it shift a little from the center part of an area | region to the edge side of the side which does not have an adjacent division area.

Here, in the above description, the lens 3 is shown as an optical system, but as a more specific optical system, for example, the optical system shown in FIG. 5 can be raised.
For example, the image acquisition device includes an infrared transmission filter (IR / PASS filter) 17, a prism 42, and a camera module 43, and the camera module 43 includes a lens unit 44 and an image sensor 4. Among these, the infrared transmission filter 17, the prism 42, and the lens unit 44 constitute an optical system.

  The prism 42 guides the light to be emitted toward the lens unit 44 after being incident while reflecting the light a plurality of times (for example, three times) from incident to emission while changing the direction. By changing, the optical system is made compact with respect to the focal length of the lens unit 44.

  Here, the camera module 43 is for imaging the finger vein, and the lens unit 44 forms an image of the imaging target on the imaging element 46 via the prism 42. The infrared transmission filter 17 is a filter that mainly transmits infrared rays, and cuts visible light and the like. Note that the term “cut” does not necessarily mean that the visible light is completely blocked, and it is sufficient if the visible light that is sufficiently transmitted can be reduced.

  The optical system of the living body acquisition apparatus is not limited to the one shown in FIG. 5, and for example, an optical system including various lenses and lens units can be used without using the prism 42.

  Further, the image acquisition device acquires a biometric image used for collation in the biometric authentication device. A biometric authentication device 60 including the image acquisition device 30 is, for example, as a subject 1 as shown in FIG. Authentication is performed using a vein pattern in a finger, and an image acquisition device 30 that captures an image of the subject 1, a signal processing unit 50 that processes a signal as image data output from the image acquisition device 30, and a signal A pattern extraction unit 51 that extracts a vein pattern for authentication in which a vein image is clarified from signal-processed image data output from the processing unit 50;

  Furthermore, the biometric authentication device 60 is registered with the registration vein pattern that has been previously captured by the image acquisition device 30, signal-processed by the signal processing unit 50, and extracted by the pattern extraction unit 51. A biometric information database 54 in which related data such as a personal authentication ID associated with the ID is registered and a registration vein pattern registered in the biometric information database 54 are captured by the image acquisition device 30 at the time of authentication. And a verification unit 52 that determines whether the vein pattern for authentication extracted by the pattern extraction unit 51 after being signal-processed by the signal processing unit 50 matches.

The image acquisition device 30 captures a vein in the finger and outputs the captured image data (video signal) to the signal processing unit 50.
The signal processing unit 50 performs signal processing such as filter processing, noise reduction processing, and gamma processing on the input image data, and extracts image data that has been corrected so that a biological pattern can be easily extracted. Output to.
The extraction unit 51 generates (extracts) an authentication vein pattern, which is image data in which a vein pattern is clarified, by performing filter processing, binarization processing, and the like, and removing false signals.

  The generated authentication vein pattern is input to the verification unit 52. The collation unit 52 compares the registration vein pattern registered in the biometric information database 54 in advance with the authentication vein pattern, and can determine that the registration vein pattern substantially matches the authentication vein pattern. It is determined whether or not there is a living body pattern.

  In this case, if the authentication vein pattern does not match any registered biometric information registered in the biometric information database 54, a mismatched result is output. If there is a registration vein pattern that substantially matches in the collation, for example, a personal authentication ID associated with the registration vein pattern is output. A device that performs a login process to a computer system using this personal authentication ID and a device that performs a login to a server on the Internet are known.

Next, an image acquisition apparatus according to a second embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 7, in the image acquisition device of the second embodiment, a plurality of LEDs 2 a, 2 b, 2 c that illuminate the subject 1, the lens 3, and the image sensor 4 are provided as in the image acquisition device of the first embodiment. I have.
In the second embodiment, the direction of the light emitted from each LED 2a, 2b, 2c (the direction of the center line of light) is made parallel in the first embodiment, whereas the light is emitted from each LED 2a, 2b, 2c. The direction of the emitted light is made to intersect at the portion of the subject 1.

  Also in this case, each part of the range in which the subject 1 is imaged is illuminated on each LED 2a, 2b, 2c, and an image can be taken using the same method as in the first embodiment. The same effect as that of the image acquisition apparatus can be obtained.

Next, an image acquisition apparatus according to a third embodiment of the present invention will be described with reference to FIGS.
The image acquisition apparatus of the third embodiment has basically the same configuration as the image acquisition apparatus shown in FIG. Note that the configuration shown in FIG.

  However, the light irradiation positions of the plurality of LEDs 2a, 2b, and 2c are arranged side by side along the above-described lateral direction (horizontal direction) of the sensors arranged vertically and horizontally in a matrix of the image sensor 4. For example, the imaged area where the subject 1 is installed is divided into three divided areas in the horizontal direction of the sensors of the image sensor 4. That is, the divided areas of the imaged area where the subject 1 is arranged are in a state of being aligned along the horizontal row of the sensors of the image sensor 4.

  As shown in FIG. 6, the first LED 2a emits light to the first divided area of the imaged area, and the subject arranged in the divided area irradiated with light to the first LED 2a. The image of the portion 1 is formed as an image X by the lens 3 in the divided range 4x of the image sensor 4. Similarly, the second LED 2b irradiates light to the portion of the subject 1 arranged in the second divided region along the lateral direction of the sensor of the above-described imaging element 4 in the imaging region. An image of the portion of the subject 1 irradiated with light on the eye LED 2 b is formed as an image Y by the lens 3 in the divided range 4 y of the image sensor 4. The third LED 2c irradiates the third divided region with light in the horizontal direction of the sensor of the above-described imaging element 4 in the imaged region, and the third LED 2b is irradiated with the light. An image of the portion of the subject 1 arranged in the region is formed as an image Z in the divided range 4 z of the image sensor 4 by the lens 3.

  The divided ranges 4a, 4b, and 4c of the image sensor 4 are arranged side by side in the lateral direction of the sensor. The direction of the output order of charges from each sensor is indicated by a zigzag arrow, and from the above-mentioned synchronization signal, after one row of sensors outputs sequentially in the horizontal direction, it moves down one by one in the vertical direction and then again in the horizontal direction. One row of sensors outputs sequentially.

Therefore, when the image sensor 4 outputs one image, after the charge is output from the sensor that overlaps the divided range 4x of the horizontal row of sensors, the charge from the sensor that overlaps the divided range 4y of the horizontal row of sensors is output. Then, after that, electric charges are output from the sensor of the portion overlapping the division range 4z in the horizontal row of sensors.
Each time the sensor moves to the next horizontal row of sensors, the above process is repeated.

  In the image reading apparatus according to the third embodiment, as shown in the timing chart of FIG. 9, the LEDs 2a, 2b, and 2c are illuminated corresponding to the output of the light amount from the sensor of each pixel of each image sensor 4.

  As in the first embodiment, when one imaging of the imaging range of the subject 1 is performed, the amount of light received once from each of the vertical and horizontal sensors in the effective range of the imaging device 4 while one Vsync signal is output. The charge corresponding to is output. At this time, as shown in FIG. 9, the output of charges from the horizontal row of sensors is started by a single HREF signal, and the sensor that outputs charges for each Pixel Clock signal is Are shifted one by one.

  At this time, lighting and extinguishing of the LEDs 2a, 2b, and 2c are controlled in accordance with the Pixel Clock signal. For example, when the number of horizontal rows in the effective range of the image sensor 4 is 300 in the vertical direction and the number of sensors in one horizontal row is 600, the Pixel Clock signal is, for example, 1 in one HREF signal period. It is output from the first time to the 600th time, and this is repeated from the first HREF signal to the 300th HREF signal.

  At this time, for example, the LED 2a is an object to be imaged in the divided range 4x of the image sensor 4 which is the range of the first to 200th horizontal rows from the left to the right among the sensors of the horizontal rows, for example. Necessary and sufficient light is irradiated to one range (one subject in the divided area), and the LED 2b forms an image on the divided area 4y of the image sensor 4 that is the range of the horizontal rows from the 201st to the 400th. Necessary and sufficient light is irradiated to the range of the subject 1, and the LED 2c is necessary and sufficient for the range of the subject 1 that is imaged in the divided range 4z of the image sensor 4 that is the range of the 401st to 600th horizontal rows. Irradiate light.

When outputting the charge indicating the light quantity, that is, the luminance of each pixel from the image sensor 4, if the HREF signal indicating the start of the output of the pixels in the horizontal row is output as described above, the charge is discharged from the head of the first horizontal row of sensors. Will be output.
Therefore, imaging of the range of the subject irradiated with light on the LED 2a is performed from the output of the first Pixel Clock signal to immediately before the output of the 201st Pixel Clock signal.

  The LED 2a is turned on from the output of the first Pixel Clock signal to the output of the 200th Pixel Clock signal (immediately before the output of the 201st Pixel Clock signal). That is, as the range of the number of times of the Pixel Clock signal, the LED 2a is turned on when the first Pixel Clock signal is output, and the LED 2a is turned off immediately before the output of the 201st Pixel Clock signal.

As a range of the number of times of the Pixel Clock signal, the LED 2b is turned on at the time of outputting the 201st Pixel Clock signal, and the LED 2b is turned off at the time of outputting the Pixel Clock signal for the 401th time (or immediately before). Next, as the range of the number of Pixel Clock signals, the LED 2c is turned on when the Pixel Clock signal is output for the 401st time, and the LED 2c is turned off after the 600th Pixel Clock signal is output.
The above operation is repeated every time electric charges are output from the horizontal row of sensors based on the output of the HREF signal. For example, when 300 sensors are arranged in the vertical direction as described above, the process is repeated each time the HREF signal is output from the first HREF signal output to the 300th HREF signal output.

As a result, in the divided range 4x of the image element 4, images corresponding to the first to 200th sensor portions of the 300 horizontal rows in the vertical direction are captured. In the divided range 4y of the image element 4, the vertical range Images corresponding to the 201st to 400th sensor portions in the 300 horizontal rows in the direction are captured, and in the divided range 4z of the image element 4, from the 401th row in the 300 horizontal rows. Images corresponding to up to 600th sensor portions are taken.
In this case as well, as in the first embodiment, the length of the finger as the subject 1 may be taken even if the image 5 is taken in which the length direction of the finger as the subject 1 is aligned with the horizontal direction of the sensor array of the image sensor 4. The image 6 may be picked up in the vertical direction along the vertical direction of the sensor array of the image sensor 4.
The imaged image is a vein in the finger as the subject 1 as in the first embodiment.

  In the third embodiment, every time a charge is output from a horizontal row of sensors, each LED 2a, 2b, 2c is turned on and off in turn, so that all the horizontal rows of sensors output the charge. However, the plurality of LEDs 2a, 2b, and 2c are basically not turned on at the same time, and the LEDs 2a, 2b, and 2c are repeatedly turned on and off at shorter times than in the first embodiment. However, the same effects as those of the first embodiment can be obtained.

  In addition, the sensors are arranged in a matrix in the vertical and horizontal directions, and after charges are sequentially output from each sensor in the horizontal direction, the sensors move to the next horizontal column in the vertical direction and again in the horizontal direction again. In the imaging device that repeats reading the electric charge from the sensor, a plurality of LEDs 2a, 2b, and 2c are arranged along the vertical direction of the sensor arrangement of the imaging device 4 in the first embodiment based on the relationship with the subject 1 to be illuminated. In the second embodiment, the plurality of LEDs 2a, 2b, 2c are arranged side by side along the horizontal direction of the arrangement of the sensors of the imaging device 4, but the plurality of LEDs 2a, 2b, 2c are arranged vertically and horizontally. May be.

  In this case, as for the vertical arrangement of the LEDs 2a, 2b, 2c, the LEDs 2a, 2b, 2c are turned on and off as in the first embodiment, and the horizontal arrangement of the LEDs 2a, 2b, 2c As in the second embodiment, the LEDs 2a, 2b, and 2c are turned on and off.

  For example, when four LEDs are arranged in a matrix, two vertically and horizontally, when a charge is output from a horizontal one row sensor using the two upper left and right LEDs at the beginning, the horizontal row sensor When the left half charge is sequentially output, the upper left LED is turned on. When the right half charge of the horizontal row sensor is sequentially output, the upper left LED is turned off and the upper right LED is turned on. When the charge is output by moving to the left end of the horizontal row of sensors, the upper right LED is turned off and the upper left LED is turned on repeatedly from the top to the horizontal row.

  Next, when charges are output from the sensors in the lower half of the image sensor 4, when the charges are read from the sensors in the horizontal row, the charges in the left half of the sensors in the horizontal row are sequentially output. In addition, the lower left LED is turned on, and when the right half charge of the horizontal row of sensors is sequentially output, the lower left LED is turned off and the lower right LED is turned on to move to the left end of the next horizontal row of sensors. When the electric charge is output, the lower right LED is turned off and the lower left LED is turned on until the bottom horizontal row is repeated.

  Also in such an image acquisition device, the same operational effects as those of the above-described embodiments can be obtained, and LEDs can be easily arranged corresponding to the imaging ranges of various shapes. Also in the case of the third embodiment, when the lighting of the LEDs 2a, 2b, 2c and the amount of emitted light are actually controlled based on the synchronization signal, the illumination is delayed at the timing of the synchronization signal. Accordingly, it is necessary to control the timing of controlling the lighting and the amount of emitted light to be slightly faster than the synchronization signal, as in the case of the first embodiment.

  Further, in the control of the LEDs 2a, 2b, and 2c, the adjacent LEDs 2a2b and 2c that illuminate the divided area adjacent to the divided area that is the target of the main illumination as described above are not sequentially turned on and extinguished. It is good also as what prevents a peripheral part from becoming darker than the center part of a division area by lowering | hanging the emitted light quantity from LED2a, 2b, 2c which illuminates the division area which becomes main illumination objects.

  In each of the above-described embodiments, an LED that outputs near-infrared light is used as a light source in order to capture a vein pattern. However, biological patterns other than the vein pattern (for example, fingerprint pattern, iris pattern, palm print pattern) You may apply this invention to imaging | photography, In that case, you may use LED which outputs visible light, and light sources other than LED.

  Further, the imaging acquisition device may be used other than the biometric authentication device, and the present invention may be applied to various imaging. Also in that case, LED may be used as a light source, and another light source may be used. In addition, although the synchronization signal is used as the charge output timing of each sensor of the image sensor, the charge output timing may be specified without using the synchronization signal.

For example, the signal obtained by removing the synchronization signal from the video signal has an output value indicating the amount of charge output from each sensor (or each peak whose height or area corresponds to the amount of charge output from each sensor) periodically. The output timing of the charge of each sensor can be obtained by the number of output values (or peaks). Therefore, the emitted light quantity of the light source may be controlled based on the count value of the number of output values.
Further, since each output value (or peak) of the video signal is periodically output, for example, the output timing of the charge of each sensor can be obtained by the time from the output start of the output value. The amount of light emitted from the light source may be controlled based on the time from the output of the video signal.

1 Subject 2a LED
2b LED
2c LED
3 Lens (optical system)
4 Image sensor 4a Division range 4b Division range 4c Division range 4x Division range 4y Division range 4Z Division range 5 Image 6 Image 7 Sensor unit 8 Control unit (control means)
10 Analysis unit (analysis means)
30 Image Acquisition Device 60 Biometric Authentication Device

Claims (15)

An image sensor that images a subject, and includes a plurality of sensors that are arranged in a matrix in the vertical and horizontal directions and detects the amount of received light respectively.
An optical system for forming an image of the subject on the image sensor;
A plurality of light sources that irradiate the subject with light as illumination and each have a different light irradiation range;
A video signal based on an amount of electric charge corresponding to the amount of received light and sequentially output from each sensor of the image sensor in a predetermined order; and a control means for controlling the amount of light emitted from the light source,
An image acquisition device for acquiring an image obtained by imaging the subject,
The control means is based on the output timing of the charge from each sensor of the image sensor and corresponds to the light irradiation range of each light source so that the emitted light amount of each light source changes individually. An image acquisition apparatus that controls the amount of emitted light.   The image acquisition apparatus according to claim 1, wherein the light source is an LED. The video signal input from the image sensor to the control means is synchronized with the signal in which the amount of the charges sequentially output from each sensor is arranged in the output order and the output timing of the charges from each sensor. It consists of an output sync signal,
The image acquisition apparatus according to claim 1, wherein the control unit individually controls the amount of light emitted from each light source based on the synchronization signal. The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. Output a horizontal sync signal,
The image acquisition apparatus according to claim 3, wherein the control unit individually controls the amount of light emitted from each light source based on the horizontal direction synchronization signal. The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. A horizontal sync signal,
Each time the switch is turned on, the sensor that outputs the charges in accordance with the horizontal arrangement order of the sensors arranged in a horizontal row specified by the horizontal synchronization signal outputs an individual synchronization signal that sequentially shifts to the next. And
The image acquisition apparatus according to claim 3, wherein the control unit individually controls the amount of light emitted from each light source based on the horizontal direction synchronization signal and the individual synchronization signal. Each light source is arranged corresponding to a plurality of divided regions obtained by dividing the imaged region on which the subject image can be formed on the image sensor when the subject is installed. The divided areas are arranged to be included in the light irradiation range,
The imaging device includes the sensor, and when an imaging range that can be imaged includes the subject in the divided area, an image of a portion of the subject in the divided area is formed by the optical system. Divided into a plurality of divided ranges corresponding to each divided area,
The control unit includes the sensor in a state where the sensor in the divided state of the image sensor outputs the charge by sequentially outputting the charges in a predetermined order by the sensor of the image sensor. 3. The amount of light emitted from each light source that individually sets each divided region as a main light irradiation range is controlled individually as the divided region corresponding to the range changes. The image acquisition device described in 1. The image pickup device is a video signal composed of a signal in which the amount of charges sequentially output from each sensor is arranged in an output order and a synchronization signal output in synchronization with the output order of the charges from each sensor. Output
The control means determines the divided region corresponding to the divided range where the sensor in a state where the charge of the image sensor is output based on a synchronization signal output from the image sensor, and 7. The amount of light emitted from each light source having each divided region as a main light irradiation range is individually controlled according to a change in the divided region determined based on the synchronization signal. The image acquisition device described. The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. Output a horizontal sync signal,
The control means sets each division range of the imaging range of the imaging device as a range of the number of times the horizontal direction synchronization signal is turned on, and the set division ranges are arranged in a row in the horizontal direction. The image acquisition apparatus according to claim 7, comprising a range of a plurality of rows continuous in the vertical direction of the sensor. The plurality of light sources are arranged side by side along the vertical columns of the sensors arranged in a matrix in the vertical and horizontal directions of the imaging device,
In response to the horizontal direction synchronization signal, the control means sequentially turns on the plurality of light sources arranged along the vertical columns of the sensors in the order along the vertical columns or is larger than other light sources. The image acquisition apparatus according to claim 8, wherein the image acquisition apparatus is controlled so as to obtain an emitted light amount. The image sensor is configured such that, when the sensors arranged in a horizontal direction among the sensors arranged in a matrix form in the vertical and horizontal directions output the electric charges sequentially in the order as the synchronization signal, the sensor at the head of the column The sensor is turned on in synchronism with the start of the output of the electric charge, and each time the sensor is turned on, the one row of sensors arranged in the horizontal direction to output the electric charge value are shifted one by one in the vertical direction. A horizontal sync signal,
Each time the switch is turned on, the sensor that outputs the charges in accordance with the horizontal arrangement order of the sensors arranged in a horizontal row specified by the horizontal synchronization signal outputs an individual synchronization signal that sequentially shifts to the next. And
The control means sets each division range of the imaging range of the imaging element as a range of the number of times the individual synchronization signal is turned on, and the set division range is a sensor arranged in a row in a vertical direction. The image acquisition apparatus according to claim 7, comprising a range of a plurality of rows continuous in the horizontal direction. The plurality of light sources are arranged side by side along a horizontal row of the sensors arranged in a matrix in the vertical and horizontal directions of the imaging device,
In response to the individual synchronization signal, the control means sequentially turns on or emits a plurality of the light sources arranged along a horizontal row of the sensors in an order along the horizontal row or larger than other light sources. The image acquisition apparatus according to claim 10, wherein the control is performed so that the amount of light is controlled every time the horizontal synchronization signal is output.   The control unit includes the sensor in a state where the sensor in the divided state of the image sensor outputs the charge by sequentially outputting the charges in a predetermined order by the sensor of the image sensor. 7. Control is performed so that each light source having each divided region as a main light irradiation range is turned on and off sequentially in accordance with the change of the divided region corresponding to the range. The image acquisition device according to claim 11.   The control unit includes the sensor in a state where the sensor in the divided state of the image sensor outputs the charge by sequentially outputting the charges in a predetermined order by the sensor of the image sensor. As the divided region corresponding to the range changes, the light source having the divided region corresponding to the divided range corresponding to the certain divided range having the light output range has the largest amount of emitted light as the divided region changes. The image acquisition device according to claim 6, wherein the image acquisition device is controlled as follows. Analyzing means for analyzing the brightness and contrast of the acquired image;
The said control means adjusts the contrast of the image acquired by controlling the timing of lighting and extinction of each light source and / or the emitted light quantity of each light source based on the analysis result of the said analysis means. The image acquisition device according to any one of claims 1 to 13.   15. The image acquisition device according to claim 1, wherein an individual is authenticated by collating a biometric pattern extracted from image data captured by the image acquisition device. A biometric authentication device.

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