Patent Description:
Some portable electronic devices, such as IC cards, acquire biometric information such as fingerprint images through sensors or the like in order to generate authentication data used for biometric authentication. Such portable electronic devices may generate authentication data, based on a plurality of biometric information.

If a user keeps touching a sensor with a finger or the like, a conventional portable electronic device acquires a plurality of identical biometric information. In such a case, the portable electronic device cannot properly generate authentication data.

<CIT> discloses a fingerprint registration method including: receiving a registered fingerprint image input at an Nth time by a user and retrieving feature points of the registered fingerprint image input at the Nth time; determining whether the registered fingerprint image input at the Nth time and registered fingerprint images input at N-<NUM> times belong to a same finger based on the feature points of the registered fingerprint image input at the Nth time and feature points of the registered fingerprint images input at the N-<NUM> times previous to the Nth time; and adding the registered fingerprint image input at the Nth time to a candidate collection of registered fingerprint images if the registered fingerprint image input at the Nth time and the registered fingerprint images input at the N-<NUM> times belong to the same finger.

<CIT> discloses tools and techniques for biometric authentication to obtain a biologic information input such as a fingerprint image, which is to be accepted or rejected as being input from an authentic user. Calculated matching scores show respective degrees of similarity between the biologic information input and several templates. The templates include a fixed registration biologic information template, as well as non-fixed learning biologic information templates which are subject to replacement.

In order to solve the above problem, there are provided a portable electronic device, an IC card and a program capable of effectively acquiring a plurality of biometric information.

According to an embodiment, a portable electronic device that executes a command from a host device includes the features of claim <NUM>.

A description will now be given of embodiments with reference to the accompanying drawings.

First, a description will be given of the first embodiment.

The IC card according to the embodiment performs an authentication process using an image of a fingerprint (fingerprint image) acquired from the user. That is, the IC card performs the authentication process by comparing the acquired fingerprint image with pre-registered authentication data (template).

The IC card generates a template by acquiring a fingerprint image from the user by use of a sensor installed in the IC card. To generate the template, the IC card acquires a fingerprint image a number of times from the same finger. The IC card generates a template based on the acquired plurality of fingerprint images and registers it therein.

<FIG> illustrates a configuration example of the IC card processing system <NUM> according to the embodiment. As shown in <FIG>, the IC card processing system <NUM> includes a host device <NUM> and an IC card <NUM> (portable electronic device). The host device <NUM> is communicably coupled to the IC card <NUM>. The IC card processing system <NUM> may include a configuration as required in addition to the configuration shown in <FIG>; alternatively, a specific configuration may be removed from the IC card processing system <NUM>.

The host device <NUM> controls the entire IC card processing system <NUM>. The host device <NUM> is coupled to the IC card <NUM> either in a contact manner or in a non-contact manner. The host device <NUM> activates the IC card <NUM> by supplying electric power to the IC card <NUM>. In addition, the host device <NUM> causes the IC card <NUM> to execute various operations by transmitting various commands to the IC card <NUM>.

In this example, the host device <NUM> transmits a command for registering a template to the IC card <NUM>. That is, the host device <NUM> causes the IC card <NUM> to acquire a plurality of fingerprint images, generate a template based on the plurality of fingerprint images, and store the generated template.

The host device <NUM> includes a reader/writer <NUM> and the like.

The reader/writer <NUM> is an interface device for transmitting/receiving data to/from the IC card <NUM>. The reader/writer <NUM> is an interface complying with the communication method of the IC card <NUM>. For example, where the IC card <NUM> is a contact type IC card, the reader/writer <NUM> is composed of a contact interface that is to be coupled to the contact portion of the IC card <NUM> physically and electrically.

Where the IC card <NUM> is a non-contact type IC card, the reader/writer <NUM> is composed of an antenna, a communication control unit, etc. that are used for wireless communications with the IC card <NUM>. The reader/writer <NUM> is configured to perform power supply, clock supply, resetting control, and data transmission/reception with reference to the IC card <NUM>.

With such functions, the reader/writer <NUM> supplies power to the IC card <NUM>, activates (starts) the IC card <NUM>, supplies clocks, performs resetting control, transmits various commands, and receives responses to the transmitted commands, under the control of the host device <NUM>.

The IC card <NUM> operates according to commands supplied from the host device <NUM>. The IC card <NUM> transmits responses to the commands to the host device <NUM>.

The IC card <NUM> includes a card-shaped casing C made of plastic or the like. The IC card <NUM> includes a module M incorporated in the casing C, a fingerprint sensor <NUM> and a display unit <NUM>. The module M is integrally formed, with an IC chip Ca, a communication unit <NUM> and an MPU <NUM> coupled thereto, and is embedded in the casing C of the IC card <NUM>.

As shown in <FIG>, the IC card <NUM> includes the module M, the fingerprint sensor <NUM>, the display unit <NUM>, etc. The module M includes the IC chip Ca, the communication unit <NUM>, the MPU <NUM>, etc. The IC chip Ca includes a processor <NUM>, a ROM <NUM>, a RAM <NUM>, an NVM <NUM>, etc. The processor <NUM> is coupled to the ROM <NUM>, the RAM <NUM>, the NVM <NUM>, the communication unit <NUM>, the MPU <NUM> and the display unit <NUM>, via a data bus or the like. The MPU <NUM> is coupled to the fingerprint sensor <NUM> via a data bus or the like.

The IC card <NUM> may include a configuration as required, in addition to the configuration shown in <FIG>, or a specific configuration may be removed from the IC card <NUM>.

The processor <NUM> functions as a control unit that controls the entire IC card <NUM>. The processor <NUM> performs various processes, based on the control programs and control data stored in the ROM <NUM> or the NVM <NUM>. For example, the processor <NUM> executes various processes in accordance with the operation control of the IC card <NUM> or the operation mode of the IC card <NUM>, by executing the programs stored in the ROM <NUM>.

For example, the processor <NUM> may be a processor that realizes control and information processing of each section in the IC card <NUM> by executing a program.

It should be noted that some of the various functions which the processor <NUM> realizes by executing the program may be realized by a hardware circuit. In this case, the processor <NUM> controls the functions executed by the hardware circuit.

The ROM <NUM> is a nonvolatile memory in which a control program, control data, etc. are stored in advance. The ROM <NUM> is incorporated in the IC card <NUM> in the manufacturing stage in a state where the control program, control data, etc. are stored. That is, the control program and control data stored in the ROM <NUM> are incorporated in advance in accordance with the specifications of the IC card <NUM>.

The RAM <NUM> is a volatile memory. The RAM <NUM> temporarily stores data, etc. that are being processed by the processor <NUM>. For example, the RAM <NUM> functions as a calculation buffer, a reception buffer, and a transmission buffer. The calculation buffer temporarily holds results of various arithmetic processes executed by the processor <NUM>. The reception buffer holds command data, etc. that are received from the reader/writer <NUM> via the communication unit <NUM>. The transmission buffer holds a message (response data) or the like that is to be transmitted to the reader/writer <NUM> via the communication unit <NUM>.

The NVM <NUM> is composed of a nonvolatile memory, such as a flash ROM, in which data can be written and rewritten. The NVM <NUM> stores a control program, an application and various data in accordance with how the IC card <NUM> is used. For example, the NVM <NUM> produces a program file, a data file, etc. A control program and various data are written in each of the produced files.

The communication unit <NUM> is an interface for transmitting/receiving data to/from the reader/writer <NUM>. That is, the communication unit <NUM> is an interface for transmitting/receiving data to/from the host device <NUM> through the reader/writer <NUM>.

Where the IC card <NUM> is realized as a contact type IC card, the communication unit <NUM> is composed of a communication control unit and a contact unit that are brought into physical and electrical contact with the reader/writer <NUM> to transmit and receive signals. For example, the IC card <NUM> is activated when it is supplied with operating power and an operating clock from the reader/writer <NUM> via the contact unit.

Where the IC card <NUM> is realized as a non-contact type IC card, the communication unit <NUM> is composed of a communication control unit, such as a modulation/demodulation circuit, and an antenna that are used for wireless communications with the reader/writer <NUM>. For example, the IC card <NUM> receives radio waves from the reader/writer <NUM> via the antenna, the modulation/demodulation circuit, etc. The IC card <NUM> is activated when operating power and an operating clock are generated from the radio wave by a power supply unit (not shown).

The fingerprint sensor <NUM> acquires a fingerprint image from a user's finger. The fingerprint sensor <NUM> acquires a fingerprint image for generating a template. For example, the fingerprint sensor <NUM> includes a CCD sensor or the like. The fingerprint sensor <NUM> may be provided with a sensor or the like that detects a change in electric capacity. The fingerprint sensor <NUM> transmits a fingerprint image to the MPU <NUM>.

The MPU <NUM> (Micro Processing Unit) processes the fingerprint image transmitted from the fingerprint sensor <NUM>. The MPU <NUM> extracts feature point information (information indicating the coordinates and feature amounts of feature points) from the fingerprint image transmitted from the fingerprint sensor <NUM>. The MPU <NUM> transmits the extracted feature point information to the processor <NUM>.

Further, the MPU <NUM> performs a verification process for the fingerprint image transmitted from the fingerprint sensor <NUM>. That is, the MPU <NUM> calculates a similarity between fingerprint images. The MPU <NUM> transmits the calculated similarity to the processor <NUM>. It should be noted here that the similarity is an index indicating that the higher the similarity, the more alike the fingerprint images are.

For example, the MPU <NUM> extracts feature point information of each fingerprint image. The MPU <NUM> calculates a similarity between the extracted feature point information as the similarity between the fingerprint images according to a predetermined algorithm. The MPU <NUM> transmits the calculated similarity to the processor <NUM>.

The MPU <NUM> performs a verification process between the template and the fingerprint image. For example, the MPU <NUM> may calculate a similarity between the template and the fingerprint image and transmit it to the processor <NUM>.

The MPU <NUM> may transmit the success or failure of the verification to the processor <NUM>.

The display unit <NUM> displays various information under the control of the processor <NUM>. For example, the display unit <NUM> may be a light (e.g., an LED (Light Emitting Diode) light) that is lit under the control of the processor <NUM>. The display unit <NUM> may be a display or the like.

Next, a description will be given of functions realized by the IC card <NUM>. The functions realized by the IC card <NUM> are realized by causing the processor <NUM> to execute programs stored in the ROM <NUM>, the NVM <NUM> or the like.

The processor <NUM> has a function of acquiring feature point information of each of fingerprint images acquired by the fingerprint sensor <NUM>.

The plurality of fingerprint images are fingerprint images of the same finger. That is, the plurality of fingerprint images are fingerprint images showing the finger at different angles or at different positions.

It is assumed that the IC card <NUM> is set in the reader/writer <NUM> and is in a state where data can be transmitted/received to/from the host device <NUM>.

The host device <NUM> transmits a command for registering a template to the IC card <NUM> through the reader/writer <NUM>.

The processor <NUM> of the IC card <NUM> receives the command through the communication unit <NUM>. Upon receiving the command, the processor <NUM> causes the fingerprint sensor <NUM> to acquire a fingerprint image. For example, the processor <NUM> activates the fingerprint sensor <NUM> through the MPU <NUM> or the like.

It is assumed here that the user places a predetermined finger on the fingerprint sensor <NUM>.

The fingerprint sensor <NUM> acquires a fingerprint image from the predetermined finger of the user. The fingerprint sensor <NUM> transmits the acquired fingerprint image to the MPU <NUM>.

The MPU <NUM> acquires the fingerprint image from the fingerprint sensor <NUM>. The MPU <NUM> extracts feature point information from the acquired fingerprint image. The MPU <NUM> transmits the extracted feature point information to the processor <NUM>.

The processor <NUM> acquires the feature point information of the fingerprint image from the MPU <NUM>.

After the feature point information of the fingerprint image is acquired, the processor <NUM> repeats the above operation. By repeating the above operation, the processor <NUM> acquires feature point information of a plurality of fingerprint images.

The processor <NUM> has a function of determining whether the fingerprint image (second biometric information) which the fingerprint sensor <NUM> acquires this time matches the fingerprint image (first biometric information) which the fingerprint sensor <NUM> acquires in the past.

For example, the processor <NUM> determines whether the fingerprint image (second biometric information) acquired this time matches the fingerprint image (first biometric information) acquired immediately before.

First, the processor <NUM> causes the MPU <NUM> to calculate a similarity between the two fingerprint images. For example, the processor <NUM> supplies the fingerprint image acquired this time and the fingerprint image acquired immediately before to the MPU <NUM> to calculate the similarity. The processor <NUM> acquires the similarity calculated by the MPU <NUM>.

After the similarity is acquired, the processor <NUM> determines whether the similarity exceeds a predetermined threshold value (first threshold value). Where the similarity exceeds the first threshold value, the processor <NUM> determines that the two fingerprint images match each other. Where the similarity is equal to or less than the first threshold value, the processor <NUM> determines that the two fingerprint images do not match each other.

Where the processor <NUM> determines that the two fingerprint images match each other (for example, where it determines that the two fingerprint images match each other with a high degree of similarity, i.e., with a first threshold value of <NUM>% or more), the processor <NUM> has a function of outputting a signal indicating that the fingerprint image acquired this time is inappropriate for use as a fingerprint image for generating a template. The signal indicating that the fingerprint image acquired this time is inappropriate for use as a fingerprint image for generating the template need not be a signal directly indicating inappropriateness; it may be a signal indicating inappropriateness eventually or indirectly.

Where the processor <NUM> determines that the two fingerprint images match each other as described above, the processor <NUM> outputs a signal indicating that the fingerprint image acquired this time is inappropriate for use as the fingerprint image for generating the template (a signal indicating inappropriateness eventually or indirectly may be output). For example, the processor <NUM> transmits a response including that signal to the host device <NUM>.

Further, the processor <NUM> causes the display unit <NUM> to display information indicating an error and prompting the user to change the finger placement. For example, where the display unit <NUM> is composed of LED lights, the processor <NUM> turns on or off a predetermined LED light or blinks it. Where the display unit <NUM> is composed of a display, the processor <NUM> may cause the display unit <NUM> to display a predetermined message.

Where the processor <NUM> determines that the two fingerprint images match each other as described above, the processor <NUM> does not use the feature point information of the fingerprint image acquired this time as feature point information for generating the template. The processor <NUM> may delete the feature point information of the fingerprint image acquired this time.

Where the processor <NUM> determines that the two fingerprint images do not match each other (for example, where it determines that the two fingerprint images do not match each other with a certain degree of similarity, i.e., with a first threshold value of <NUM>% or less), the processor <NUM> uses the feature point information of the fingerprint image acquired this time as feature point information for generating a template, i.e., as one of samples in which the feature point information are appropriately dispersed. Further, the processor <NUM> may output information indicating that one fingerprint image has been successfully acquired. For example, the processor <NUM> causes the display unit <NUM> to display that information. For example, where the display unit <NUM> is composed of LED lights, the processor <NUM> turns on or off a predetermined LED light or blinks it. Where the display unit <NUM> is composed of a display, the processor <NUM> may cause the display unit <NUM> to display a predetermined message.

Where the similarity between the two fingerprint images is equal to or less than a second threshold value lower than the first threshold value (for example, where it is determined that the two fingerprint images match each other with a low degree of similarity, i.e., with a second threshold value of <NUM>% or less), the processor <NUM> may output a signal indicating that the fingerprint image acquired this time is inappropriate for use as a fingerprint image for generating the template. The signal need not be a signal directly indicating inappropriateness but may be a signal indicating inappropriateness eventually or indirectly. For example, the processor <NUM> may determine that the user has placed another finger on the fingerprint sensor <NUM> and output error information prompting the user to place the same finger on the fingerprint sensor <NUM>. In this case, the processor <NUM> does not use the feature point information of the fingerprint image acquired this time as the feature point information for generating the template. That is, where the similarity is between the first threshold value and the second threshold value, the processor <NUM> may use the feature point information of the fingerprint image acquired this time as the feature point information for generating the template.

The processor <NUM> has a function of generating a template, based on a plurality of feature point information.

The processor <NUM> counts the number of feature point information acquired to generate the template. That is, the processor <NUM> counts the number of feature point information of fingerprint images that do not match the fingerprint image acquired in the past.

Where that number reaches a predetermined threshold value, the processor <NUM> generates a template, based on the feature point information of a plurality of fingerprint images that do not match the fingerprint image acquired in the past, i.e., a plurality of fingerprint images acquired with some variations. That is, the processor <NUM> generates a template from a plurality of feature point information according to a predetermined algorithm. The processor <NUM> may generate a template from each of the plurality of feature point information.

After the template is generated, the processor <NUM> registers the generated template. For example, the processor <NUM> stores the generated template as authentication data in the MPU <NUM>.

After the template is stored, the processor <NUM> transmits a response indicating that the registration of the template is completed to the host device <NUM> through the communication unit <NUM>.

Next, a description will be given of an operation example of the IC card <NUM>.

<FIG> is a flowchart illustrating the operation example of the IC card <NUM>.

It is assumed here that the IC card <NUM> is set in the reader/writer <NUM> and is in a state where data can be transmitted/received to/from the host device <NUM>.

First, the processor <NUM> of the IC card <NUM> determines whether or not a command for registering the template has been received from the host device <NUM> through the communication unit <NUM> (S11). Where it is determined that the command for registering the template has not been received from the host device <NUM> (S11, NO), the processor <NUM> returns to S11.

Where it is determined that the command for registering the template has been received from the host device <NUM> (S11, YES), the processor <NUM> resets the counter n that counts the number of feature point information for generating the template (n=<NUM>) (S12).

Where the counter n is reset, the processor <NUM> acquires a fingerprint image by means of the fingerprint sensor <NUM>, the MPU <NUM> and the like, and acquires feature point information of the fingerprint image (S13). After the feature point information is acquired, the processor <NUM> determines whether n is equal to <NUM> (S14).

Where it is determined that n is not equal to <NUM> (S14, NO), the processor <NUM> causes the MPU <NUM> to verify the fingerprint image acquired this time with the fingerprint image acquired in the past (S15). Where it is determined that n is equal to <NUM> (S14, YES) or where it is determined that the two fingerprint images do not match each other (S16, NO), the processor <NUM> causes the display unit <NUM> to display information indicating that one fingerprint image has been successfully acquired (S17).

After the information indicating that one fingerprint image has been successfully acquired is displayed on the display unit <NUM>, the processor <NUM> increments n (S18). After n is incremented, the processor <NUM> determines whether n has reached a predetermined threshold value (S19).

For example, where it is determined that the two fingerprint images match each other because a high similarity rate is obtained (S16, YES), the processor <NUM> causes the display unit <NUM> to display an error (S20).

Where it is determined that n has not reached the predetermined threshold value (S19, NO) or where an error is displayed on the display unit <NUM> (S20), the processor <NUM> returns to S13.

Where it is determined that n has reached the predetermined threshold value (S19, YES), the processor <NUM> generates a template, based on n feature point information for generating the template (S21). After the template is generated, the processor <NUM> stores the generated template in the MPU <NUM> (S22).

After the generated template is stored in the MPU <NUM>, the processor <NUM> transmits a response indicating that the registration of the template is completed to the host device <NUM> through the communication unit <NUM> (S23). After transmitting the response to the host device <NUM>, the processor <NUM> ends the operation.

The processor <NUM> may determine whether the fingerprint image acquired this time matches each of the fingerprint images acquired in the past. Where one or more fingerprint images match the fingerprint image acquired this time, the processor <NUM> may output a signal indicating that the fingerprint image acquired this time is inappropriate for use as the fingerprint image for generating the template, such as a signal indicating an error.

Where one or more fingerprint images match the fingerprint image acquired this time, the processor <NUM> does not have to use the feature point information of the fingerprint image acquired this time as the feature point information for generating the template.

Further, the processor <NUM> may generate a template without being based on the feature point information.

For example, the processor <NUM> may generate a network obtained by machine learning using a plurality of fingerprint images and adopt such a network as a template. Further, the processor <NUM> may extract a pattern from a plurality of fingerprint images and generate information indicating that pattern as a template.

The template may be a plurality of fingerprint images that are determined as not matching the past fingerprint images.

What the template is and how it is generated are not limited to specific configurations.

The IC card <NUM> may be configured to acquire biometric information other than fingerprint images. For example, the IC card <NUM> may acquire an image of a vein, an iris or the like as biological information. The biometric information acquired by the IC card <NUM> is not limited to a specific configuration.

The processor <NUM> may realize the functions (or part of the functions) of the MPU <NUM>. Further, the MPU <NUM> may realize part of the functions of the processor <NUM>.

Where an acquired fingerprint image matches the fingerprint image acquired in the past, the IC card configured as described above cannot reflect an appropriate variation as a template, so that a signal indicating that the acquired fingerprint image is inappropriate for use as a fingerprint image for generating a template is output (the signal need not be a signal directly indicating inappropriateness but may be a signal indicating inappropriateness eventually or indirectly). Therefore, the IC card can prompt the user to change the placement of a finger when the user continuously inputs a fingerprint image without releasing the finger from the fingerprint sensor. In particular, in the case of a non-contact type IC card, where a plurality of fingerprints are successively collected, the fingerprint images tend to attain matching easily. Where the non-contact IC card is used for collecting fingerprints, it is relatively difficult to release a finger from the sensor once and then place the finger on the sensor again. As a result, matching fingerprint images are easily collected and the IC card is in an error state at that time, so that the IC card has an effective means for notifying the user of the error.

In order to detect whether the placement of a finger is changed, a conventional processor has to acquire a fingerprint image from the fingerprint sensor in real time and detect that the finger has been released from the fingerprint sensor.

On the other hand, the IC card according to the embodiment can acquire fingerprint images in which the finger is placed differently, without detecting that the finger is released from the fingerprint sensor by the above operation.

Therefore, the IC card can effectively acquire a plurality of biometric information for generating a template.

Next, a description will be given of an IC card processing system <NUM> according to the second embodiment.

The IC card <NUM> of the IC card processing system <NUM> of the second embodiment differs from the above-mentioned IC card <NUM> in that a response is transmitted to the host device <NUM> each time the feature point information of one fingerprint image is acquired. Accordingly, the other components will be denoted by the same reference symbols, and a detailed description of such components will be omitted.

Since the configurations of the host device <NUM> and the IC card <NUM> are similar to those of the first embodiment, the description thereof will be omitted.

The host device <NUM> transmits a command for acquiring one fingerprint image to generate a template to the IC card <NUM> through the reader/writer <NUM>.

The host device <NUM> receives a response from the IC card <NUM> through the reader/writer <NUM>, indicating that one fingerprint image has been successfully acquired. In this case, the host device <NUM> may cause a display unit or the like to display information indicating that one fingerprint image has been successfully acquired.

Further, the host device <NUM> receives a response from the IC card <NUM> through the reader/writer <NUM>, indicating that the acquisition of one fingerprint image has failed. In this case, the host device <NUM> may cause the display unit or the like to display information indicating that the acquisition of one fingerprint image has failed. In addition, the host device <NUM> may cause the display unit or the like to display information prompting the user to change the finger placement.

Where the processor <NUM> of the IC card <NUM> receives a command to acquire one fingerprint image for generating a template, the processor <NUM> acquires a fingerprint image through the fingerprint sensor <NUM>, the MPU <NUM> or the like, and acquires feature point information of the fingerprint image.

Where the fingerprint image acquired this time and the fingerprint image acquired in the past do not match each other, the processor <NUM> causes the communication unit <NUM> to transmit a response indicating that one fingerprint image has been successfully acquired to the host device <NUM>. In this case, the processor <NUM> may output information indicating that one fingerprint image has been successfully acquired.

Where the fingerprint image acquired this time and the fingerprint image acquired in the past match each other, the processor <NUM> causes the communication unit <NUM> to transmit a response indicating that the acquisition of one fingerprint image has failed to the host device <NUM>. In this case, the processor <NUM> may cause the display unit <NUM> to display information indicating an error and prompting the user to change the finger placement.

First, the processor <NUM> of the IC card <NUM> resets the counter n (n = <NUM>) that counts the number of feature point information for generating a template (S31). After n is reset, the processor <NUM> determines whether or not a command for acquiring one fingerprint image to generate a template has been received from the host device <NUM> through the communication unit <NUM> (S32).

Where it is determined that the command for acquiring one fingerprint image to generate the template has not been received from the host device <NUM> (S32, NO), the processor <NUM> returns to S32.

Where it is determined that a command for acquiring one fingerprint image to generate the template has been received from the host device <NUM> (S32, YES), the processor <NUM> acquires the fingerprint image through the fingerprint sensor <NUM>, the MPU <NUM>, and the like, and acquires feature point information of the fingerprint image (S33). After the feature point information is acquired, the processor <NUM> determines whether n is equal to <NUM> (S34).

Where it is determined that n is not equal to <NUM> (S34, NO), the processor <NUM> causes the MPU <NUM> to verify the fingerprint image acquired this time with the fingerprint image acquired in the past (S35). Where it is determined that n is equal to <NUM> (S34, YES) or where it is determined that the two fingerprint images do not match each other (S36, NO), the processor <NUM> causes the display unit <NUM> to display information indicating that one fingerprint image has been successfully acquired (S37).

After the information indicating that one fingerprint image has been successfully acquired is displayed on the display unit <NUM>, the processor <NUM> transmits a response indicating that one fingerprint image has been successfully acquired to the host device <NUM> through the communication unit <NUM> (S38).

After the response indicating that one fingerprint image has been successful acquired is transmitted to the host device <NUM>, the processor <NUM> increments n (S39). After n is incremented, the processor <NUM> determines whether n has reached a predetermined threshold value (S40).

Where it is determined that the two fingerprint images match each other (S36, YES), the processor <NUM> causes the display unit <NUM> to display an error (S41). After the error is displayed on the display unit <NUM>, the processor <NUM> transmits a response indicating that the acquisition of one fingerprint image has failed to the host device <NUM> through the communication unit <NUM> (S42).

Where it is determined that n has not reached a predetermined threshold value (S40, NO), or where a response indicating that the acquisition of one fingerprint image has failed is transmitted to the host device <NUM> (S42), the processor <NUM> returns to S32.

Where it is determined that n has reached the predetermined threshold value (S40, YES), the processor <NUM> generates a template, based on n feature point information for generating the template (S43). After the template is generated, the processor <NUM> stores the generated template in the MPU <NUM> (S44).

After the generated template is stored in the MPU <NUM>, the processor <NUM> ends the operation.

After the template is stored in the MPU <NUM>, the processor <NUM> may send a response indicating that the template registration has been completed to the host device <NUM> through the communication unit <NUM>.

The communications between the IC card <NUM> and the host device <NUM> may be cut off each time the IC card <NUM> acquires a fingerprint image. That is, the user may separate the IC card <NUM> from the host device <NUM> each time the IC card <NUM> acquires a fingerprint image.

Claim 1:
A portable electronic device (<NUM>) that executes a command from a host device (<NUM>), comprising:
a sensor (<NUM>) configured to acquire biometric information; and
a processor (<NUM>) configured to:
cause the sensor (<NUM>) to acquire first biometric information for generating a template used for authentication;
cause the sensor (<NUM>) to acquire second biometric information for generating the template after acquiring the first biometric information; and
not use the second biometric information for template generation where the similarity exceeds the first threshold value and where the similarity is lower than a second threshold value that is lower than the first threshold value;
wherein the biometric information is a fingerprint image;
characterized in that the processor (<NUM>) is further configured to output a signal indicating that the second biometric information is inappropriate for use as biometric information for generating the template, where a similarity between the first biometric information and the second biometric information exceeds a first threshold value.