Patent Description:
An iris authentication system that performs an iris authentication by capturing an image of an iris of a target person that is one example of an imaging target is known as one example of an imaging system that is configured to capture an image of the imaging target. For example, a Patent Literature <NUM> discloses an iris authentication in a walk-through type that is configured to enable the iris authentication even when the target person does not stop. Specifically, the Patent Literature <NUM> discloses the iris authentication system that is provided with a wide angle camera and a plurality of iris cameras and that selects, from the plurality of iris cameras, the iris camera that should be used for the authentication by processing an image of the wide angle camera.

In addition, there are Patent Literatures <NUM> and <NUM> as a background art document relating to this disclosure.

Furthermore, the published patent application <CIT>-<NUM>-<NUM>, discloses a system and method where a wide angle camera images an approaching person; from the position of the eyes, a direction is predicted for a second camera to focus on the eyes of the person for authentication.

The iris authentication system disclosed in the Patent Literature <NUM> has such a technical problem that there is a possibility that it is not able to capture the image of the moving target person properly by using the iris camera. Specifically, the iris authentication system that is provided with the wide angle camera and the plurality of iris cameras is required to select the iris camera that should be used for the authentication (furthermore, set a parameter of the selected iris camera, if needed) before the moving target person reaches a focus position of the iris camera. Thus, it is desired that the iris authentication system capture the image of the target person by using the wide angle camera before the moving target person reaches the focus position of the iris camera and select the iris camera that should be used for the authentication on the basis of the image of the wide angle camera. However, the Patent Literature <NUM> does not consider this point.

Note that there is a possibility that the above described technical problem occurs in not only the iris authentication system but also any imaging system that controls a second imaging apparatus to capture an image of a moving imaging target on the basis of an image of the imaging target captured by a first imaging apparatus.

It is therefore an example object of this disclosure to provide an imaging system, an imaging method, a control apparatus, a computer program and a recording medium that can solve the above described technical problem. By way of example, an example object of this disclosure is to provide an imaging system, an imaging method, a control apparatus, a computer program and a recording medium that can capture an image of a moving imaging target properly.

The invention is set out solely in the appended claims. Embodiments according to the invention are solely the specific combinations of features as defined in the claims. The examples below in this section are not according to the invention and are present for illustration purposes only.

A first example aspect of an imaging system for solving the technical problem is provided with: a first imaging apparatus that captures an image of an imaging target that is located at a first point; a second imaging apparatus a focus position of which is set at a second point that is located at a forward side along a moving direction of the imaging target than the first point; and a control apparatus that controls the second imaging apparatus to capture an image of the imaging target that is located at the second point on the basis of the image captured by the first imaging apparatus.

A second example aspect of an imaging system for solving the technical problem is provided with: an imaging apparatus a state of which is switchable between a first state and a second state, that captures an image of an imaging target that is located at a first point in the first state, and that captures an image of the imaging target that is located at a second point, which is located at a forward side along a moving direction of the imaging target than the first point, in the second state; and a control apparatus that switches the imaging apparatus from the first state to the second state by controlling the imaging apparatus on the basis of the image captured by the imaging apparatus in the first state.

A first example aspect of an imaging method for solving the technical problem includes: an obtaining step that obtains an image captured by a first imaging apparatus that captures an image of an imaging target that is located at a first point; and a controlling step that controls, on the basis of the image obtained at the obtaining step, a second imaging apparatus a focus position of which is set at a second point to capture an image of the imaging target located at the second point that is located at a forward side along a moving direction of the imaging target than the first point.

A second example aspect of an imaging method for solving the technical problem includes: an obtaining step that obtains an image captured by an imaging apparatus in a first state from the imaging apparatus a state of which is switchable between the first state and a second state, that captures an image of an imaging target that is located at a first point in the first state, and that captures an image of the imaging target that is located at a second point, which is located at a forward side along a moving direction of the imaging target than the first point, in the second state; and a controlling step that switches the imaging apparatus from the first state to the second state by controlling the imaging apparatus on the basis of the image obtained at the obtaining step.

A first example aspect of a control apparatus for solving the technical problem is provided with: an obtaining unit that obtains an image captured by a first imaging apparatus that captures an image of an imaging target that is located at a first point; and a controlling unit that controls, on the basis of the image obtained by the obtaining unit, a second imaging apparatus a focus position of which is set at a second point to capture an image of the imaging located at the second point that is located at a forward side along a moving direction of the imaging target than the first point.

A second example aspect of a control apparatus for solving the technical problem is provided with: an obtaining unit that obtains an image captured by an imaging apparatus in a first state from the imaging apparatus a state of which is switchable between the first state and a second state, that captures an image of an imaging target that is located at a first point in the first state, and that captures an image of the imaging target that is located at a second point, which is located at a forward side along a moving direction of the imaging target than the first point, in the second state; and a controlling unit that switches the imaging apparatus from the first state to the second state by controlling the imaging apparatus on the basis of the image obtained by the obtaining unit.

One example aspect of a computer program for solving the technical problem allows a computer to perform the first or second example aspect of the imaging method described above.

One example aspect of a recording medium for solving the technical problem is a recording medium on which the one example aspect of the computer program described above is recorded.

According to the example aspect of each of the imaging system, the imaging method, the control apparatus, the computer program and the recording medium described above, it is possible to capture an image of a moving imaging target properly.

Hereinafter, an example embodiment of an imaging system, an imaging method, a control apparatus, a computer program and a recording medium will be described with reference to the drawings. The following describes an iris authentication system <NUM> to which the example embodiment of the imaging system, the imaging method, the control apparatus, the computer program and the recording medium is applied. The iris authentication system <NUM> performs an iris authentication operation for performing an authentication of an authentication target person T on the basis of a pattern of an iris of the authentication target person T that is one example of an imaging target. The iris authentication system <NUM> may be used as a part of a system for automating an immigration procedure in an airport (what we call ABC (Automated Border Control)). In this case, the iris authentication system <NUM> may be an iris authentication system in a walk-through type that performs the authentication of moving authentication target person T. In the below described description, an example in which the iris authentication system <NUM> is the iris authentication system in the walk-through type will be described. However, the iris authentication system <NUM> is not limited to the iris authentication system that is described in this paragraph as one example, and may be used as any iris authentication system that is configured to perform the authentication of the authentication target person T. Note that the iris authentication system <NUM> is one example of an "imaging system" in a supplementary note described below.

Firstly, with reference to <FIG>, an entire configuration of the iris authentication system <NUM> in the present example embodiment will be described. <FIG> is a block diagram that illustrates the entire configuration of the iris authentication system <NUM> in the present example embodiment.

As illustrated in <FIG>, the iris authentication system <NUM> is provided with: a wide camera <NUM> that is one specific example of a "first imaging apparatus " in the supplementary note described below; a plurality of iris cameras <NUM> each of which is one specific example of a "second imaging apparatuses " in the supplementary note described below; and an iris authentication apparatus <NUM> that is one specific example of a "control apparatus " in the supplementary note described below. The iris authentication system <NUM> is further provided with: a human detection sensor <NUM> that is one specific example of a "first detection apparatus " in the supplementary note described below; and a human detection sensor <NUM> that is one specific example of a "second detection apparatus " in the supplementary note described below. <FIG> illustrates an example in which the iris authentication system <NUM> is provided with n (note that n is an integer that is equal to or larger than <NUM>) iris cameras <NUM>. In the below described description, the n iris cameras <NUM> are referred to as an iris camera <NUM>-<NUM>, an iris camera <NUM>-<NUM>,. , and an iris camera <NUM>-n, respectively, if needed. Note that the number of the iris cameras <NUM> may be set appropriately on the basis of a characteristic of each iris camera <NUM> (for example, at least one of a range of a field of view of each iris camera <NUM>, a resolution of each iris camera <NUM> and so on).

Each of the wide camera <NUM> and the plurality of iris cameras <NUM> is an imaging apparatus that is configured to capture an image of the authentication target person T. Next, with reference to <FIG>, the wide camera <NUM> and the plurality of iris cameras <NUM> will be described in more detail. <FIG> is a conceptional diagram that illustrates a positional relationship between the wide camera <NUM> and the plurality of iris cameras <NUM> and the authentication target person T.

As illustrated in <FIG>, the wide camera <NUM> captures the image of the authentication target person T with a range of the field of view that is wider than the range of the field of view of each iris camera <NUM>. Namely, the range of the field of view of the wide camera <NUM> is wider than the range of the field of view of each iris camera <NUM>. Specifically, the range of the field of view of the wide camera <NUM> is set to be a proper range so that the wide camera <NUM> is configured to capture the image of the authentication target person T regardless of the height of the authentication target person T. Namely, the range of the field of view of the wide camera <NUM> is set to be a proper range so that the wide camera <NUM> is configured to capture the image of the relatively tall authentication target person T and to capture the image of the relatively short authentication target person T too. Especially, the range of the field of view of the wide camera <NUM> is set to be a proper range so that the wide camera <NUM> is configured to capture an image of a target portion TP (an eye including the iris in the present example embodiment) of the authentication target person T that is used for the authentication.

Note that the "range of the field of view of the camera" in the present example embodiment means a range including a scene an image of which is capturable by the camera, and may be referred to as an "imaging range". A size of the range of the field of view typically becomes wider as an angle of view (in other word, a view angle) of the camera becomes wider. Thus, an optical system (for example, a lens) of the wide camera <NUM> is typically an optical system that has a field of view wider than that of an optical system of each iris camera <NUM>. Namely, an angle of view of the wide camera <NUM> is wider than an angle of view of each iris camera <NUM>. Moreover, the angle of view of the camera typically becomes wider as a focal length of an optical system (for example, a lens) of the camera becomes shorter. Thus, a focal length of the optical system of the wide camera <NUM> is shorter than a focal length of the optical system of each iris camera <NUM>.

The wide camera <NUM> captures the image of the authentication target person T that is located at a trigger point P1. Namely, the range of the field of view of the wide camera <NUM> is set to be a proper range so that the wide camera <NUM> is configured to capture the image of the authentication target person T that is located at the trigger point P1. The trigger point P1 is a point that is located on a moving route of the authentication target person T. Moreover, the trigger point P1 is a point that is located at a nearer side than a reference point P0 as seen from the authentication target person T moving toward the trigger point P1. Namely, the trigger point P1 is a point that is located at a backward side (namely, a rear side) than the reference point P0 along a moving direction of the authentication target person T. Moreover, the trigger point P1 is a point that is away from the reference point P0 by a distance D1 along the moving direction of the authentication target person T. The reference point P0 may be a point at which each iris camera <NUM> is disposed, for example. Alternatively, the reference point P0 may be a destination for the moving authentication target person T, for example. The destination may be a point through which the authentication target person T passes after the authentication (for example, a point at which a gate is disposed in the airport).

In an example illustrated in <FIG>, the authentication target person T moves from a left side to a right side on a paper. Therefore, in the example illustrated in <FIG>, the trigger point P1 is a point that is away from the reference point P0 toward the left side on the paper by the distance D1. Note that the authentication target person T may move along a linear route in which the moving direction is always the same, or may move along a route (for example, a curved route or a winding route) in which the driving direction changes in the middle.

It is preferable that the wide camera <NUM> be disposed so that a focus position of the wide camera <NUM> is located at the trigger point P1. Incidentally, the "focus position" in the present example embodiment means a certain area that ranges in front and back of a best focus position (for example, an area that is allowed to be regarded as in focus and corresponds to a depth of field). In this case, it is preferable that the wide camera <NUM> be disposed so that the focus position of the wide camera <NUM> is an area including the trigger point P1 (namely, so that the trigger point P1 is located in an area corresponding to the focus position). Conversely, the trigger point P1 is set at the focus position of the wide camera <NUM>.

The wide camera <NUM> has a resolution that allows a face of the authentication target person T located at the trigger point P1 to be recognized from a wide image <NUM> that is an image captured by the wide camera <NUM>. Especially, the wide camera <NUM> has a resolution that allows a position in the wide image <NUM> of the target portion TP (namely, the eye) of the authentication target person T located at the trigger point P1 to be recognized from the wide image <NUM>.

On the other hand, each iris camera <NUM> captures the image of the authentication target person T that is located at a focus point P2. Namely, the range of the field of view of each iris camera <NUM> is set to be a proper range so that each iris camera <NUM> is configured to capture the image of the authentication target person T that is located at the focus point P2. The focus point P2 is a point that is located on the moving route of the authentication target person T, as with the trigger point P1. Moreover, the pint point P2 is a point that is located at a nearer side than the reference point P0 as seen from the authentication target person T moving toward the focus point P2, as with the trigger point P1. Namely, the focus point P2 is a point that is located at a backward side (namely, a rear side) than the reference point P0 along the moving direction of the authentication target person T. Moreover, the focus point P2 is a point that is away from the reference point P0 by a distance D2 along the moving direction of the authentication target person T. In the example illustrated in <FIG>, the authentication target person T moves from the left side to the right side on the paper. Therefore, in the example illustrated in <FIG>, the focus point P2 is a point that is away from the reference point P0 toward the left side on the paper by the distance D2.

The distance D2 between the focus point P2 and the reference point P0 is shorter than the distance D1 between the trigger point P1 and the reference point P0. Thus, the focus point P2 is located at a forward side (namely, a front side) than the trigger point P1 along the moving direction of the authentication target person T. In other words, the trigger point P1 is located at a backward side (namely, a rear side) than the focus point P2 along the moving direction of the authentication target person T. Therefore, the moving authentication target person T passes through the focus point P2 after passing through the trigger point P1. In other words, the moving authentication target person T passes through the trigger point P1 before passing through the focus point P2. Note that the distances D1 and D2 may be set to be any values as long as a relationship that the distance D2 is shorter than the distance D1 is satisfied. As one example, the distances D1 and D2 may be set <NUM> and <NUM>, respectively.

Each iris camera <NUM> is disposed so that a focus position of each iris camera <NUM> is located at the focus point P2. Specifically, it can be said that each iris camera <NUM> is disposed so that the focus position of each iris camera <NUM> is an area including the focus point P2 (namely, so that the focus point P2 is located in an area corresponding to the focus position). Conversely, the focus point P2 is set at the focus position of each iris camera <NUM>. Incidentally, since the angle of view of the wide camera <NUM> is wider than the angle of view of each iris camera <NUM> (namely, the focal length of the optical system of the wide camera <NUM> is shorter than the focal length of the optical system of each iris camera <NUM>) as described above, the area corresponding to the focus position of the wide camera <NUM> is wider than the area corresponding to the focus position of each iris camera <NUM>.

The plurality of iris cameras <NUM> are disposed so that the ranges of the field of view of the plurality of iris cameras <NUM> overlap partially in a vertical direction (alternatively, a desired direction that is different from the vertical direction) at the focus point P2. In the example illustrated in <FIG>, the plurality of iris cameras <NUM> are disposed so that a lower end part of the range of the field of view of the iris camera <NUM>-k (note that k is an integer that satisfies <NUM> ≦ k<n) and an upper end part of the range of the field of view of the iris camera <NUM>-m (note that m is an integer that satisfies <NUM><k+<NUM>=m ≦ n) overlap at the focus point P2. As a result, scenes that are partially the same are included in two images respectively captured by two iris cameras <NUM> the range of the field of view of which overlap partially. In the example illustrated in <FIG>, the same scene is included in a lower end part of the image captured by the iris camera <NUM>-k and an upper end part of the image captured by the iris camera <NUM>-m.

The plurality of iris cameras <NUM> are disposed so that a combined range of field of view that is obtained by combining the ranges of the field of view of the plurality of iris cameras <NUM> has a predetermined horizontal size in a horizontal direction and has a predetermined vertical size in the vertical direction. The predetermined horizontal size may be a size (for example, <NUM>) that allows the target portion TP of the authentication target person T located at the focus point P2 to be included in the combined range of the field of view. The predetermined vertical size may be a size (for example, <NUM>) that allows the target portion TP of the authentication target person T located at the focus point P2 to be included in the combined range of the field of view regardless of the height of the authentication target person T.

Each iris camera <NUM> has a resolution that allows the target portion TP of the authentication target person T located at the focus point P2 to be recognized from an iris image <NUM> that is an image captured by each iris camera <NUM>. Especially, each iris camera <NUM> has a resolution that allows the pattern of the iris of the authentication target person T located at the focus point P2 to be recognized from the iris image <NUM> that is the image captured by each iris camera <NUM>.

Note that the range of the field of view of the wide camera <NUM> partially overlaps with the range of the field of view of at least one of the plurality of iris cameras <NUM>. In this case, both of the authentication target person T (especially, the target portion TP) located at the trigger point P1 and the authentication target person T (especially, the target portion TP) located at the focus point P2 may be included in the range of the field of view of the wide camera <NUM>. For example, both of the authentication target person T (especially, the target portion TP) located at the trigger point P1 and the authentication target person T (especially, the target portion TP) located at the focus point P2 may be included in the range of the field of view of each iris camera <NUM>. However, the range or the field of view of the wide camera <NUM> may not overlap with the range of the field of view of each of the plurality of iris cameras. For example, the authentication target person T (especially, the target portion TP) located at the trigger point P1 may be included in the range of the field of view of the wide camera <NUM> and the authentication target person T (especially, the target portion TP) located at the focus point P2 may not be included in the range of the field of view of the wide camera <NUM>. For example, the authentication target person T (especially, the target portion TP) located at the focus point P2 may be included in the range of the field of view of each iris camera <NUM> and the authentication target person T (especially, the target portion TP) located at the trigger point P1 may not be included in the range of the field of view of each iris camera <NUM>.

Again in <FIG>, the human detection sensor <NUM> is a detection apparatus for detecting whether or not the authentication target person T is located at the trigger point P1. A detected result by the human detection sensor <NUM> is outputted to the iris authentication apparatus <NUM>. The detected result by the human detection sensor <NUM> is used as a condition to determine whether or not the wide camera <NUM> captures the image of the authentication target person T located at the trigger point P1.

The human detection sensor <NUM> is a detection apparatus for detecting whether or not the authentication target person T is located at the focus point P2. A detected result by the human detection sensor <NUM> is outputted to the iris authentication apparatus <NUM>. The detected result by the human detection sensor <NUM> is used as a condition to determine whether or not the iris camera <NUM> captures the image of the authentication target person T located at the focus point P2.

The iris authentication apparatus <NUM> controls an entire operation of the iris authentication system <NUM>. Especially in the present example embodiment, the iris authentication apparatus <NUM> performs an iris authentication operation. The iris authentication operation is an operation that includes a process of selecting one iris camera <NUM> for capturing the image of the authentication target person T located at the focus point P2 from the plurality of iris cameras <NUM> on the basis of the wide image <NUM> captured by the wide camera <NUM> and a process of performing the authentication of the authentication target person T on the basis of the iris image <NUM> captured by the selected one iris camera <NUM>, for example.

Next, with reference to <FIG>, a configuration of the iris authentication apparatus <NUM> will be described. <FIG> is a block diagram that illustrates a hardware configuration of the iris authentication apparatus <NUM> in the present example embodiment.

As illustrated in <FIG>, the iris authentication apparatus <NUM> is provided with a CPU (Central Processing Unit) <NUM>, a RAM (Random Access Memory) <NUM>, a ROM (Read Only Memory) <NUM>, a storage apparatus <NUM>, an input apparatus <NUM>, and an output apparatus <NUM>. The CPU <NUM>, the RAM <NUM>, the ROM <NUM>, the storage apparatus <NUM>, the input apparatus <NUM>, and the output apparatus <NUM> are interconnected through a data bus <NUM>. However, the iris authentication apparatus <NUM> may not be provided with at least one of the RAM <NUM>, the ROM <NUM>, the storage apparatus <NUM>, the input apparatus <NUM>, and the output apparatus <NUM>.

The CPU <NUM> reads a computer program. For example, the CPU <NUM> may read a computer program stored in at least one of the RAM <NUM>, the ROM <NUM> and the storage apparatus <NUM>. For example, the CPU <NUM> may read a computer program stored in a computer-readable recording medium, by using a not-illustrated recording medium reading apparatus. The CPU <NUM> may obtain (namely, read) a computer program from a not-illustrated apparatus disposed outside the iris authentication apparatus <NUM>, through a network interface. The CPU <NUM> controls the RAM <NUM>, the storage apparatus <NUM>, the input apparatus <NUM>, and the output apparatus <NUM> by executing the read computer program. Especially in the present example embodiment, when the CPU <NUM> executes the read computer program, a logical functional block(s) for performing the iris authentication operation is implemented in the CPU <NUM>. Namely, the CPU <NUM> is configured to function as a controller for implementing the logical block for performing the iris authentication operation.

One example of the logical block that is implemented in the CPU <NUM> for performing the iris authentication operation is illustrated in <FIG>. As illustrated in <FIG>, in the CPU <NUM>, an image obtaining unit <NUM> that is one specific example of a "obtaining unit" in the supplementary note described below, an area detection unit <NUM> that is one specific example of a "controlling unit" in the supplementary note described below, a coordinate estimation unit <NUM> that is one specific example of the "controlling unit" in the supplementary note described below, a camera set unit <NUM> that is one specific example of the "controlling unit" in the supplementary note described below, an imaging control unit <NUM> that is one specific example of the "controlling unit" in the supplementary note described below, and an authentication unit <NUM> are implemented as logical blocks for performing the iris authentication operation. Note that an operation of each of the image obtaining unit <NUM>, the area detection unit <NUM>, the coordinate estimation unit <NUM>, the camera set unit <NUM>, the imaging control unit <NUM> and the authentication unit <NUM> will be described later in detail with reference to <FIG>, and thus, the detailed description thereof is omitted here.

Again in <FIG>, The RAM <NUM> temporarily stores the computer program to be executed by the CPU <NUM>. The RAM <NUM> temporarily stores the data that is temporarily used by the CPU <NUM> when the CPU <NUM> executes the computer program. The RAM <NUM> may be, for example, a D-RAM (Dynamic RAM).

The ROM <NUM> stores the computer program to be executed by the CPU <NUM>. The ROM <NUM> may otherwise store fixed data. The ROM <NUM> may be, for example, a P-ROM (Programmable ROM).

The storage apparatus <NUM> stores the data that is stored for a long term by the iris authentication apparatus <NUM>. The storage apparatus <NUM> may operate as a temporary storage apparatus of the CPU <NUM>. The storage apparatus <NUM> may include, for example, at least one of a hard disk apparatus, a magneto-optical disk apparatus, an SSD (Solid State Drive), and a disk array apparatus.

The input apparatus <NUM> is an apparatus that receives an input instruction from a user of the iris authentication apparatus <NUM>. The input apparatus <NUM> may include, for example, at least one of a keyboard, a mouse, and a touch panel.

The output apparatus <NUM> is an apparatus that outputs an information about the iris authentication apparatus <NUM>, to the outside. For example, the output apparatus <NUM> may be a display apparatus that is configured to display an information about the iris authentication apparatus <NUM>.

Next, with reference to <FIG>, a flow of the operation (namely, the iris authentication operation) of the iris authentication system <NUM> in the present example embodiment will be described. <FIG> is a flow chart that illustrates the flow of the operation (namely, the iris authentication operation) of the iris authentication system <NUM> in the present example embodiment.

As illustrated in <FIG>, the imaging control unit <NUM> determines whether or not the authentication target person T is located at the trigger point P1 on the basis of the detected result by the human detection sensor <NUM> (a step S11). As a result of the determination at the step S11, when it is determined that the authentication target person T is not located at the trigger point P1 (the step S11: No), the process at the step S11 is repeatedly performed. On the other hand, as a result of the determination at the step S11, when it is determined that the authentication target person T is located at the trigger point P1 (the step S11: Yes), the imaging control unit <NUM> controls the wide camera <NUM> to capture the image of the authentication target person T located at the trigger point P1 (a step S12). As a result, the wide camera <NUM> captures the image of the authentication target person T located at the trigger point P1 (the step S12). The wide image <NUM> captured by the wide camera <NUM> is obtained by the image obtaining unit <NUM> (the step S12).

Then, the area detection unit <NUM> detects, as a target area TA, an image part of the wide image <NUM> in which the target portion TP is included by performing an image processing on the wide image <NUM> obtained at the step S12 (a step S21). For example, as illustrated in <FIG> that is a planar view illustrating one example of the target area TA in the wide image <NUM>, the area detection unit <NUM> detects, as the target area TA, a rectangular (alternatively, another shaped) image part of the wide image <NUM> in which the target portion TP is included. Furthermore, the area detection unit <NUM> calculates a position coordinate C of the detected target area TA in the wide image <NUM> (the step S21). The position coordinate C may include a coordinate of a desired part (for example, a corner part) of the target area TA. The position coordinate C is typically a two-dimensional coordinate (alternatively, a two-dimensional vector). Note that the position coordinate C that is calculated at the step S21 is referred to as a "position coordinate C(wide:P1)" in the below described description for convenience of description.

Then, the coordinate estimation unit <NUM> estimates, on the basis of the position coordinate C(wide:P1) of the target area TA that is calculated at the step S21, the position coordinate C of the target area TA in the wide image <NUM> that is obtained under the assumption that the wide camera <NUM> has captured the image of the authentication target person T that is located at the focus point P2 (a step S22). More specifically, the coordinate estimation unit <NUM> estimates the position coordinate C of the target area TA in the wide image <NUM> that is expected to be obtained under the assumption that the wide camera <NUM> has captured the image of the authentication target person T that has moved from the trigger point P1 to the focus point P2 (the step S22). Namely, the coordinate estimation unit <NUM> estimates the position coordinate C of the target area TA in the wide image <NUM> that is expected to be obtained under the assumption that the wide camera <NUM> has captured the image of the authentication target person T that is located at the focus point P2 in a situation where the authentication target person T located at the trigger point P1 has moved to the focus point P2 (the step S22). Note that the position coordinate C that is estimated at the step S22 is referred to as a "position coordinate C(wide:P2)" in the below described description for convenience of description. Moreover, in the below described description, the wide image <NUM> that is actually obtained by means of the wide camera <NUM> capturing the image of the authentication target person T located at the trigger point P1 is referred to as a "wide image <NUM>(P1)" and the wide image <NUM> that is expected to be obtained under the assumption that the wide camera <NUM> has captured the image of the authentication target person T that has moved from the trigger point P1 to the focus point P2 is referred to as a "wide image <NUM>(P2)" to distinguish the both, for convenience of description.

Since the trigger point P <NUM> is different from the focus point P2, there is a high possibility that at least one of a size and a position of the authentication target person T in the wide image <NUM>(P <NUM>) is different from at least one of a size and a position of the authentication target person T in the wide image <NUM>(P2), as illustrated in <FIG> that illustrates the wide image <NUM>(P1) and <FIG> that illustrates the wide image <NUM>(P2). Especially, there is a high possibility that at least one of the size and the position of the authentication target person T in the wide image <NUM>(P1) is even more different from at least one of the size and the position of the authentication target person T in the wide image <NUM>(P2), as the trigger point P1 is away from the focus point P2 more. Thus, there is typically a high possibility that the position coordinate C(wide:P1) is different from the position coordinate C(wide:P2).

The coordinate estimation unit <NUM> may estimate the position coordinate C(wide:P2) from the position coordinate C(wide:P1) by using a first correspondence information that indicates a correspondence (typically, a positional relationship) between an object included in the wide image <NUM>(P1) and the same object included in the wide image <NUM>(P2). This first correspondence information typically indicates a correspondence between a position coordinate in the wide image <NUM>(P1) of the object included in the wide image <NUM>(P1) and a position coordinate in the wide image <NUM>(P2) of the same object included in the wide image <NUM>(P2) that is expected to be obtained when the object has moved from the trigger point P1 to the focus point P2 as with the authentication target person T. Thus, the first correspondence information is substantially information to which a moving aspect of the authentication target person T (for example, a moving direction of the authentication target person T) is reflected. Namely, the first correspondence information substantially information relating to the moving aspect of the authentication target person T (for example, the moving direction of the authentication target person T).

The first correspondence information may be calculated in advance (for example, before the iris authentication operation is performed) on the basis of the wide image <NUM> that is obtained by means of the wide camera <NUM> actually capturing the image of the object located at the trigger point P1 and the wide image <NUM> that is obtained by means of the wide camera <NUM> actually capturing the image of the same object that has moved from the trigger point P1 to the focus point P2 as with the authentication target person T. Specifically, the first correspondence information may be calculated on the basis of the position coordinate in the wide range <NUM> of the object located at the trigger point P1 and the position coordinate in the wide range <NUM> of the object located at the focus point P2. Alternatively, the wide image <NUM> that is expected to be obtained when the wide camera <NUM> captures the image of the object located at the trigger point P1 and the wide image <NUM> that is expected to be obtained when the wide camera <NUM> captures the image of the object that has moved from the trigger point P1 to the focus point P2 as with the authentication target person T may be calculated by a simulation and the like, and the first correspondence information may be calculated on the basis of a result of the simulation in advance. In the simulation, at least one of a position of the wide camera <NUM>, a camera parameter of the wide camera <NUM>, a position of the trigger point P1 and a position of the focus point P2 may be considered. Alternatively, the first correspondence information may be calculated by any other method.

A first transformation matrix H1 that transforms the position coordinate C(wide:P1) to the position coordinate C(wide:P2) is one example of the first correspondence information. In this case, the coordinate estimation unit <NUM> may estimate the position coordinate C(wide:P2) by using an equation of position coordinate C(wide:P2) = H1 × position coordinate C(wide:P1). This first transformation matrix H1 may be a matrix that represents a projective transformation to project an object located at the trigger point P1 onto a virtual plane located at the focus point P2, for example.

Then, the coordinate estimation unit <NUM> estimates, on the basis of the position coordinate C(wide:P2) that is estimated at the step S22, the position coordinates C of the target areas TA in the plurality of iris images <NUM> that are obtained, respectively, under the assumption that the plurality of iris cameras <NUM> have captured the image of the authentication target person T that is located at the focus point P2 (a step S23). More specifically, the coordinate estimation unit <NUM> estimates the position coordinates C of the target areas TA in the plurality of iris images <NUM> that are expected to be obtained, respectively, under the assumption that the plurality of iris cameras <NUM> have captured the image of the authentication target person T that has moved from the trigger point P1 to the focus point P2 (the step S23). Namely, the coordinate estimation unit <NUM> estimates the position coordinates C of the target areas TA in the plurality of iris images <NUM> that are expected to be obtained, respectively, under the assumption that the plurality of iris cameras <NUM> have captured the image of the authentication target person T that is located at the focus point P2 in a situation where the authentication target person T located at the trigger point P1 has moved to the focus point P2 (the step S23). Note that the position coordinate C that is estimated at the step S23 is referred to as a "position coordinate C(iris:P2)" in the below described description for convenience of description. Moreover, in the below described description, the iris image <NUM> that is expected to be obtained under the assumption that each iris camera <NUM> has captured the image of the authentication target person T that has moved from the trigger point P1 to the focus point P2 is referred to as an "iris image <NUM>(P2)".

As described above, the range of the field of view of each iris camera <NUM> is narrower than the range of the field of view of wide camera <NUM>. Thus, as illustrated in <FIG> that illustrates a relationship between the wide image <NUM>(P2) and the plurality of iris images <NUM>, the target area TA included in the wide image <NUM>(P2) is not necessarily included in all of the plurality of iris images <NUM>(P2). Namely, there is a possibility that the plurality of iris images <NUM>(P2) include both of the iris image <NUM>(P2) in which the target area TA is included and the iris image <NUM>(P2) in which the target area TA is not included. In an example illustrated in <FIG>, the target area TA is included in the iris image <NUM>(P2)-<NUM> that is expected to be captured by the iris camera <NUM>-<NUM> and is not included in the iris images <NUM>(P2)-<NUM> to <NUM>(P2)-n that are expected to be captured by the iris cameras <NUM>-<NUM> to <NUM>-n. Thus, at the step S23, the coordinate estimation unit <NUM> determines, on the basis of the position coordinate C(wide:P2), the iris image <NUM>(P2) in which the target area TA is expected to be included, and estimates the position coordinate C(iris:P2) of the target area TA in the determined iris image <NUM>(P2).

The coordinate estimation unit <NUM> may estimate the position coordinate C(iris:P2) from the position coordinate C(wide:P2) by using a second correspondence information that indicates a correspondence (typically, a positional relationship) between an object included in the wide image <NUM>(P2) and the same object included in each of the plurality of iris images <NUM>(P2). This second correspondence information typically indicates a correspondence between a position coordinate in the wide image <NUM>(P2) of the object included in the wide image <NUM>(P2) and a position coordinate in the iris image <NUM>(P2) of the same object included in each of the plurality of iris images <NUM>(P2).

The second correspondence information may be calculated in advance (namely, before the iris authentication operation is performed) on the basis of the wide image <NUM> that is obtained by means of the wide camera <NUM> actually capturing the image of the object located at the focus point P2 and the plurality of iris images <NUM> that are obtained by means of the plurality of iris cameras <NUM> actually capturing the image of the same object that is located at the focus point P2, respectively. Specifically, the second correspondence information may be calculated on the basis of the position coordinate in the wide range <NUM> of the object at the focus point P2 and the position coordinate in the iris range <NUM> of the object at the focus point P2. Alternatively, the wide image <NUM> that is expected to be obtained when the wide camera <NUM> captures the image of the object located at the focus point P2 and the plurality of iris images <NUM> that are expected to be obtained when the plurality of iris cameras <NUM> capture the image of the same object that is located at the focus point P2, respectively, may be calculated by a simulation and the like, and the second correspondence information may be calculated on the basis of a result of the simulation in advance. In the simulation, at least one of the position of the wide camera <NUM>, the camera parameter of the wide camera <NUM>, positions of the plurality of iris cameras <NUM>, camera parameters of the plurality of iris cameras <NUM>, the position of the trigger point P1 and the position of the focus point P2 may be considered. Alternatively, the second correspondence information may be calculated by any other method.

A second transformation matrix H2 that transforms the position coordinate C(wide:P2) to the position coordinate C(iris:P2) is one example of the second correspondence information. In this case, the coordinate estimation unit <NUM> may estimate the position coordinate C(iris:P2) by using an equation of position coordinate C(iris:P2) = H2 × position coordinate C(wide:P2).

Then, the camera set unit <NUM> selects, on the basis of the position coordinate C(iris:P2) that is estimated at the step S23, one iris camera <NUM> for capturing the image of the authentication target person T located at the focus point P2 from the plurality of iris cameras <NUM> (a step S31). Specifically, as described above, the coordinate estimation unit <NUM> determines, on the basis of the position coordinate C(wide:P2), the iris image <NUM>(P2) in which the target area TA is included. Therefore, the camera set unit <NUM> selects, as one iris camera <NUM> for capturing the image of the authentication target person T located at the focus point P2, the iris camera <NUM> of the plurality of iris cameras <NUM> that corresponds to the iris image <NUM>(P2) in which the target area TA is included. In the example illustrated in <FIG>, the camera set unit <NUM> selects the iris camera <NUM>-<NUM> that corresponds to the iris image <NUM>(P2)-<NUM> as one iris camera <NUM> for capturing the image of the authentication target person T located at the focus point P2.

Then, the camera set unit <NUM> sets a region of interest (ROI: Region of Interest) IA that defines an image part, which is actually obtained (namely, read) for performing the iris authentication, of the iris image <NUM> captured by one iris camera <NUM> selected at the step S31 (a step S32). Specifically, as illustrated in <FIG>, the camera set unit <NUM> sets, to the region of interest IA, a rectangular (alternatively, another shaped) area, in which the target portion TP is expected to be included, of the iris image <NUM> captured by selected one iris camera <NUM>. Namely, as illustrated in <FIG>, the camera set unit <NUM> sets, to the region of interest IA, a rectangular (alternatively, another shaped) area, which includes the target area TA, corresponds to the target area TA or is expected to be included in the target area TA, of the iris image <NUM> captured by selected one iris camera <NUM>, for example. As described above, the position coordinate C(iris:P2) estimated at the step S23 indicates the position coordinate of the target area TA in the iris image <NUM>(P2). Since the target portion TP is included in the target area TA, the camera set unit <NUM> is able to set the region of interest IA properly on the basis of the position coordinate C(iris:P2). In the example illustrated in <FIG>, the camera set unit <NUM> sets a part of the iris image <NUM>(P2)-<NUM> to the region of interest IA.

When the region of interest IA is set, the iris authentication system <NUM> operates in a region of interest mode. In this case, the image obtaining unit <NUM> obtains an image part of the iris image <NUM> (namely, a part of an image data of the iris image <NUM>) in the region of interest IA, instead of obtaining whole of the iris image <NUM> captured by the iris camera <NUM>. Namely, the image obtaining unit <NUM> may not obtain an image part of the iris image <NUM> (namely, a residual part of the image data of the iris image <NUM>) in an area other than the region of interest IA. As a result, a frame rate at which the image obtaining unit <NUM> obtains the iris image <NUM> from the iris camera <NUM> substantially improves, compared to a case where whole of the iris image <NUM> is obtained. For example, when a half area of the iris image <NUM> is set to the region of interest IA, the frame rate improves to be the double, compared to a case where whole of the iris image <NUM> is obtained. Thus, even when the frame rate of the iris camera <NUM> itself is lower than a frame rate that is necessary for the iris authentication, the image obtaining unit <NUM> is able to obtain the iris image at the frame rate that is necessary for the iris authentication.

Then, the imaging control unit <NUM> determines whether or not the authentication target person T is located at the focus point P2 on the basis of the detected result by the human detection sensor <NUM> (a step S41). Namely, the imaging control unit <NUM> determines whether or not the authentication target person T that has been determined to be located at the trigger point P1 moves to the focus point P2 on the basis of the detected result by the human detection sensor <NUM> (the step S41). As a result of the determination at the step S41, when it is determined that the authentication target person T is not located at the focus point P2 (the step S41: No), the process at the step S41 is repeatedly performed. On the other hand, as a result of the determination at the step S41, when it is determined that the authentication target person T is located at the focus point P2 (the step S41: Yes), the imaging control unit <NUM> controls one iris camera <NUM> selected at the step S31 to capture the image of the authentication target person T located at the focus point P2 (a step S42). As a result, the selected one iris camera <NUM> captures the image of the authentication target person T located at the focus point P2 (the step S42). The iris image <NUM> captured by the selected one iris camera <NUM> (especially, the image part of the iris image <NUM> in the region of interest IA) is obtained by the image obtaining unit <NUM> (the step S42).

Then, the authentication unit <NUM> performs the iris authentication by using the iris image <NUM> obtained at the step S42 (a step S51). For example, the authentication unit <NUM> determines the patter of the iris of the authentication target person T on the basis of the iris image <NUM> obtained at the step S42. Then, the authentication unit <NUM> determines whether or not the determined pattern matches a pattern that is registered in a data base stored in the storage apparatus <NUM> and the like. When the determined pattern matches the pattern registered in the database, the authentication unit <NUM> determines that the authentication target person T is a proper person. When the determined pattern matches the pattern registered in the database, the authentication unit <NUM> determines that the authentication target person T is not a proper person.

As described above, in the iris authentication system <NUM>, the wide camera <NUM> captures the image of the authentication target person T that is located at the trigger point P1 that is different from (specifically, is located at a backward side of) the focus point P2 before the iris camera <NUM> captures the image of the authentication target person T that is located at the focus point P2. Thus, the iris authentication system <NUM> is able to select one iris camera <NUM> for capturing the image of the authentication target person T before the authentication target person T is located at the focus point P2. In other words, the iris authentication system <NUM> is able to select one iris camera <NUM> for capturing the image of the authentication target person T (furthermore, setting the region of interest IA) by using a time during which the authentication target person T moves from the trigger point P1 to the focus point P2. Thus, the iris authentication system <NUM> is able to capture the image of the moving authentication target person T (especially, the target portion TP thereof) properly.

Even when the trigger point P1 is different from the focus point P2 as described above, the iris authentication system <NUM> is able to select one iris camera <NUM> for capturing the image of the authentication target person T properly on the basis of the wide image <NUM>(P1) captured by the wide camera <NUM>. This is because the iris authentication system <NUM> estimates, on the basis of the position coordinate C(wide:P1) of the target area TA in the wide image <NUM>(P2), the position coordinate C(wide:P2) of the target area TA in the wide image <NUM>(P2) that is expected to be obtained under the assumption that the wide camera <NUM> has captured the image of the authentication target person T that has moved to the focus point P2, and then, estimates the position coordinate C(iris:P2) of the target area TA in the iris image <NUM>(P2) that is expected to be obtained under the assumption that the iris camera <NUM> has captured the image of the authentication target person T that has moved to the focus point P2.

Here, since the trigger point P1 is different from the focus point P2, there is a high possibility that the position coordinate C(wide:P1) is different from the position coordinate C(wide:P2) as described above, as illustrated in <FIG> described above. Therefore, if the position coordinate C(wide:P1) is used as the position coordinate C(wide:P2) as it is, one iris camera <NUM> that is selected to capture the image of the authentication target person T is not able to capture the image of the target portion TP properly. Namely, if the position coordinate C(wide:P1) is used as the position coordinate C(wide:P2) as it is, there is a possibility that the camera set unit <NUM> mistakenly selects, as one iris camera <NUM> for capturing the image of the authentication target person T, the iris camera <NUM> that is not able to capture the image of the target portion TP of the authentication target person T located at the focus point P2. However, in the present example embodiment, the position coordinate C(wide:P2) is estimated from the position coordinate C(wide:P1) and then the position coordinate C(iris:P2) is estimated. Thus, there is lower possibility that one iris camera <NUM> that is selected to capture the image of the authentication target person T is not able to capture the image of the target portion TP properly. Namely, there is a lower possibility that the iris camera <NUM> that is not able to capture the image of the target portion TP of the authentication target person T located at the focus point P2 is mistakenly selected as one iris camera <NUM> for capturing the image of the authentication target person T. Thus, it can be said that a process of estimating the position coordinate C(wide:P2) from the position coordinate C(wide:P1) contributes a proper selection of the iris camera <NUM> that captures the image of the target portion TP of the authentication target person T located at the focus point P2 (namely, a proper imaging of the target portion TP by the iris camera <NUM>).

Moreover, in the present example embodiment, the plurality of human detection sensors (namely, the human detection sensors <NUM> and <NUM>) that correspond to the trigger point P1 and the focus point P2, respectively, are disposed. Thus, the iris authentication system <NUM> is able to properly determine whether or not the authentication target person T is located at each of the trigger point P1 and the focus point P2. Namely, the iris authentication system <NUM> is able to properly capture the image of the authentication target person T that is located at the trigger point P1 by the wide camera <NUM> and is able to properly capture the image of the authentication target person T that is located at the focus point P2 by the iris camera <NUM>.

Firstly, with reference to <FIG>, an entire configuration of an iris authentication system 1a in a first modified example will be described. <FIG> is a block diagram that illustrates the entire configuration of the iris authentication system 1a in the first modified example. Note that a detailed description of a component that is same as a component of the above described iris authentication system <NUM> is omitted by assigning the same reference number thereto.

As illustrated in <FIG>, the iris authentication system 1a is different from the iris authentication system <NUM> in that it is provided with a single common camera 7a instead of the wide camera <NUM> and the plurality of iris cameras <NUM>. Another characteristic of the iris authentication system 1a may be same as another characteristic of iris authentication system <NUM>.

The common camera 7a is an imaging apparatus that is configured to capture the image of the authentication target person T, as with the wide camera <NUM> and the plurality of iris cameras <NUM>. The common camera 7a is configured to switch a state thereof between a wide imaging state in which it is configured to serve as the wide camera <NUM> and an iris imaging state in which it is configured to serve as at least one of the plurality of iris cameras <NUM>. Note that the wide imaging state and the iris imaging state are examples of a "first state" and a "second state" in the supplementary note described below, respectively.

The common camera 7a in the wide imaging state is equivalent to the above described wide camera <NUM>. Namely, the common camera 7a in the wide imaging state operates as with the above described wide camera <NUM>. Thus, a characteristic of the common camera 7a in the wide imaging state may be same as the above described wide camera <NUM>, and thus, its detailed description is omitted.

The common camera 7a in the iris imaging state is equivalent to at least one of the plurality of iris cameras <NUM> described above. Namely, the common camera 7a in the iris imaging state operates as with at least one of the plurality of iris cameras <NUM> described above. Thus, a characteristic of the common camera 7a in the iris imaging state may be same as at least one of the plurality of iris cameras <NUM> described above, and thus, its detailed description is omitted. Note that the range of the field of view of the common camera 7a in the iris imaging state is typically same as the combined range of the field of view (see <FIG>) that is obtained by combining the ranges of the field of view of the plurality of iris cameras <NUM>. Thus, the common camera 7a in the iris imaging state is substantially equivalent to the plurality of iris cameras <NUM> described above that is regarded as a single camera.

In order to switch the state, the common camera 7a may be provided with an optical system having a variable optical characteristic (for example, a focal length), for example. In this case, the focal length of the common camera 7a in the wide imaging state is typically shorter than the focal length of the common camera 7a in the iris imaging state. As a result, the common camera 7a is configured to serve as the wide camera <NUM> and is configured to serve as at least one of the plurality of iris cameras <NUM>.

As one example, the common camera 7a may be provided with an optical system including what we call a zoom lens. In this case, when a focal length of the optical system including the zoom lens is set to be a relatively short first distance (for example, a first distance that corresponds to the focal length of the above described wide camera <NUM>), the state of the common camera 7a is the wide imaging state. Namely, a focus position of the common camera 7a is set at the area including the trigger point P1 and the common camera 7a is configured to capture the image of the authentication target person T located at the trigger point P1 with the relatively wide range of the field of view (namely, with the relatively wide angle of view). On the other hand, when the focal length of the optical system including the zoom lens is set to be a relatively long second distance (for example, a second distance that corresponds to the focal length of the above described iris camera <NUM>) from the first distance, the state of the common camera 7a is switched from the wide imaging state to the iris imaging state. Namely, the focus position of the common camera 7a is set at the area including the focus point P2 and the common camera 7a is configured to capture the image of the authentication target person T located at the focus point P2 with the relatively narrow range of the field of view (namely, with the relatively narrow angle of view). Moreover, when the focal length of the optical system including the zoom lens is set to be the first distance from the second distance, the state of the common camera 7a is switched from the iris imaging state to the wide imaging state.

In the first modified example, an operation including a process of setting, on the basis of the image captured by the common camera 7a in the wide imaging state, the region of interest (ROI: Region of Interest) IAthat defines the image part, which is actually obtained (namely, read) for performing the iris authentication, of the image captured by the common camera 7a in the iris imaging state and a process of performing the authentication of the authentication target person T on the basis of the image captured by the common camera 7a in the iris imaging state, is performed as the iris authentication operation, for example. Next, the iris authentication operation in the first modified example will be described in more detail. Incidentally, in the below described description, the image captured by the common camera 7a in the wide imaging state is referred to as the "wide image <NUM>" for convenience of description, because the image captured by the common camera 7a in the wide imaging state is substantially equivalent to the wide image <NUM> captured by the wide camera <NUM>. Moreover, the image captured by the common camera 7a in the iris imaging state is referred to as the "iris image <NUM>" for convenience of description, because the image captured by the common camera 7a in the iris imaging state is substantially equivalent to an image that is obtained by combining the plurality of iris images <NUM> captured by the plurality of iris cameras <NUM>, respectively.

Next, with reference to <FIG>, a flow of the operation (namely, the iris authentication operation) of the iris authentication system 1a in the first modified example will be described. <FIG> is a flow chart that illustrates the flow of the operation (namely, the iris authentication operation) of the iris authentication system 1a in the first modified example. Note that a detailed description of a process that is same as a process described in the above described <FIG> is omitted by assigning the same step number thereto.

As illustrated in <FIG>, in the first modified example, when it is determined that the authentication target person T is located at the trigger point P1 (the step S11: Yes), the imaging control unit <NUM> controls the common camera 7a to capture the image of the authentication target person T located at the trigger point P1 (a step S12a). In this case, the imaging control unit <NUM> controls the common camera 7a so that the state of the common camera 7a becomes the wide imaging state before controlling the common camera 7a to capture the image of the authentication target person T located at the trigger point P1. For example, when the common camera 7a is provided with the optical system including the zoom lens as described above, the imaging control unit <NUM> controls the zoom lens (for example, moves a movable lens included in the zoom lens) so that the focal length of the optical system including the zoom lens is set to be the relatively short first distance. Then, the imaging control unit <NUM> controls the common camera 7a to capture the image of the authentication target person T located at the trigger point P1. As a result, the common camera 7a captures the image of the authentication target person T located at the trigger point P1 (the step S12a). The wide image <NUM>(P1) captured by the common camera 7a is obtained by the image obtaining unit <NUM> (the step S12a).

Then, the area detection unit <NUM> detects, as the target area TA, an image part of the wide image <NUM>(P1) in which the target portion TP is included by performing the image processing on the wide image <NUM>(P1) obtained at the step S12a (the step S21). Furthermore, the area detection unit <NUM> calculates the position coordinate C of the detected target area TA in the wide image <NUM>(P1) (the step S21).

Then, the coordinate estimation unit <NUM> estimates, on the basis of the position coordinate C(wide:P1) of the target area TA that is calculated at the step S21, the position coordinate C(wide:P2) of the target area TA in the wide image <NUM>(P2) that is expected to be obtained under the assumption that the common camera 7a in the wide imaging state has captured the image of the authentication target person T that has moved from the trigger point P1 to the focus point P2 (a step S22a). Note that the coordinate estimation unit <NUM> may estimate the position coordinate C(wide:P2) from the position coordinate C(wide:P1) by using the first correspondence information that indicates the correspondence between the object included in the wide image <NUM>(P1) and the same object included in the wide image <NUM>(P2) at the step S22a, as with the above described step S22. However, the first correspondence information in the first modified example is different from the above described first correspondence information in that it is information targeting at the common camera 7a.

Then, the coordinate estimation unit <NUM> estimates, on the basis of the position coordinate C(wide:P2) that is estimated at the step S22, the position coordinate C(iris:P2) of the target area TA in the iris image <NUM> that is expected to be obtained under the assumption that the common camera 7a in the iris imaging state has captured the image of the authentication target person T that has moved from the trigger point P1 to the focus point P2 (a step S23a). Note that the coordinate estimation unit <NUM> may estimate the position coordinate C(iris:P2) from the position coordinate C(wide:P2) by using the second correspondence information that indicates the correspondence between the object included in the wide image <NUM>(P2) and the same object included in the iris image <NUM>(P2) at the step S23a, as with the above described step S23. However, the second correspondence information in the first modified example is different from the above described second correspondence information targeting at the wide camera <NUM> and the iris cameras <NUM> in that it is information targeting at the common camera 7a in the wide imaging state and the common camera 7a in the iris imaging state (especially, the common camera 7a in the iris imaging state that is configured to capture the image of the target portion TP of the authentication target person T located at the focus point P2). Incidentally, in the first modified example, since the common camera 7a is used instead of the plurality of iris cameras <NUM>, the coordinate estimation unit <NUM> estimates, on the basis of the position coordinate C(wide:P2), the position coordinate C(iris:P2) of the target area TA in the iris image <NUM>(P2) without performing a process of determining one iris image <NUM>(P2) in which the target area TA is expected to be included from the plurality of iris images <NUM>(P2).

Then, the camera set unit <NUM> sets, on the basis of the position coordinate C(iris:P2) that is estimated at the step S23, the region of interest (ROI: Region of Interest) IA that defines the image part, which is actually obtained (namely, read) for performing the iris authentication, of the iris image <NUM> captured by one common camera 7a in the iris imaging state (a step S32a). Note that the process at the step S32a may be same as the process at the above described step S32 that targets the iris camera <NUM>, except that it targets at the common camera 7a.

Then, when it is determined that the authentication target person T is located at the focus point P2 (the step S41: Yes), the imaging control unit <NUM> controls the common camera 7a to capture the image of the authentication target person T located at the focus point P2 (a step S42a). In this case, the imaging control unit <NUM> controls the common camera 7a so that the state of the common camera 7a is switched from the wide imaging state to the iris imaging state before controlling the common camera 7a to capture the image of the authentication target person T located at the focus point P2. Specifically, the imaging control unit <NUM> controls the common camera 7a so that the state of the common camera 7a is switched from the wide imaging state to the iris imaging state before the iris image <NUM> is obtained at the step S42a after the wide image <NUM> is obtained at the step S12a. When the common camera 7a is provided with the optical system including the zoom lens as described above, the imaging control unit <NUM> controls the zoom lens (for example, moves the movable lens included in the zoom lens) so that the focal length of the optical system including the zoom lens is set to be the relatively long second distance. Namely, the imaging control unit <NUM> changes the focal length of the optical system including the zoom lens from the relatively short first distance to the relatively long second distance. As a result, the state of the common camera 7a is switched from the wide imaging state to the iris imaging state. Then, the imaging control unit <NUM> controls the common camera 7a to capture the image of the authentication target person T located at the focus point P2. As a result, the common camera 7a captures the image of the authentication target person T located at the focus point P2 (the step S42a). The iris image <NUM> captured by the common camera 7a (especially, the image part of the iris image <NUM> in the region of interest IA) is obtained by the image obtaining unit <NUM> (the step S42a).

Then, the authentication unit <NUM> performs the iris authentication by using the iris image <NUM> obtained at the step S42 (the step S51).

The iris authentication system 1a in the first modified example described above is able to achieve an effect that is same as an effect achievable by the above described iris authentication system <NUM>.

In the above described description, the coordinate estimation unit <NUM> estimates the position coordinate C(wide:P2) from the position coordinate C(wide:P1) and then estimates the position coordinate C(iris:P2) from the position coordinate C(wide:P2) by using two correspondence information, the first and second correspondence information. However, the coordinate estimation unit <NUM> may estimate the position coordinate C(iris:P2) directly from the position coordinate C(wide:P1) by using single correspondence information to which both of the first and second correspondence information are reflected (for example, single transformation matrix that corresponds to the first transformation matrix H1 × the second transformation matrix H2. Even in this case, an operation for estimating the position coordinate C(iris:P2) directly from the position coordinate C(wide:P1) is equivalent to an operation for estimating the position coordinate C(wide:P2) from the position coordinate C(wide:P1) and then estimating the position coordinate C(iris:P2) from the position coordinate C(wide:P2), as long as the firs correspondence information is reflected to the single correspondence information.

In the above described description, single trigger point P1 is set. However, a plurality of trigger points P1 distances from the reference point P0 of which are different from each other may be set. In this case, the wide camera <NUM> may capture the image of the authentication target person T located at at least one trigger point P1 of the plurality of trigger points P1. Alternatively, the iris authentication system <NUM> may be provided with a plurality of wide cameras <NUM> that correspond to the plurality of trigger points P1, respectively. Moreover when the plurality of trigger points P1 are set, the iris authentication system <NUM> may be provided with a plurality of human detection sensors <NUM> that correspond to the plurality of trigger points P1, respectively.

The iris authentication system <NUM> may be provided with single iris camera <NUM>. In this case, the range of the field of view of the iris camera <NUM> may be set to be a proper range so that the iris camera <NUM> is configured to capture the image of the target portion TP of the authentication target person T located at the focus point P2 regardless of the height of the authentication target person T. Moreover, when the iris authentication system <NUM> is provided with single iris camera <NUM>, the camera set unit <NUM> may not perform the process at the step S31 of <FIG> (namely, the process of selecting one iris camera <NUM> that captures the image of the authentication target person T).

The camera set unit <NUM> may not perform the process of setting the region of interest IA (the process corresponding to the step S32 of <FIG> or the step S32a of <FIG>). In this case, the iris authentication system <NUM> may not operates in the region of interest mode. Specifically, the image obtaining unit <NUM> may obtain whole of the iris image <NUM> captured by the iris camera <NUM> or the common camera 7a. The authentication unit <NUM> may perform the iris authentication by using whole of the iris image <NUM> captured by the iris camera <NUM> or the common camera 7a.

In the above described description, the iris authentication apparatus <NUM> is provided with the image obtaining unit <NUM>, the area detection unit <NUM>, the coordinate estimation unit <NUM>, the camera set unit <NUM>, the imaging control unit <NUM> and the authentication unit <NUM>. However, as illustrated in <FIG> that is a block diagram illustrating a modified example of the iris authentication apparatus <NUM>, the iris authentication apparatus <NUM> may not be provided with at least one of the area detection unit <NUM>, the coordinate estimation unit <NUM> and the camera set unit <NUM>. In this case, the imaging control unit <NUM> may perform the process that is performed by each of the area detection unit <NUM>, the coordinate estimation unit <NUM> and the camera set unit <NUM>. Alternatively, an apparatus outside the iris authentication apparatus <NUM> may perform the process that is performed by each of the area detection unit <NUM>, the coordinate estimation unit <NUM> and the camera set unit <NUM>. Moreover, as illustrated in <FIG>, the iris authentication apparatus <NUM> may not be provided with the authentication unit <NUM>. In this case, an apparatus outside the iris authentication apparatus <NUM> may perform the process that is performed by the authentication unit <NUM>.

In the above described description, the iris authentication system <NUM> is provided with the human detection sensor <NUM>. However, the iris authentication system <NUM> may not be provided with the human detection sensor <NUM>. In this case, the wide camera <NUM> or the common camera 7a may keep capturing the image of the scene in the range of the field of view at a predetermined frame rate (namely, an imaging rate) regardless of whether the authentication target person T is located at the trigger point P1. Typically, the wide camera <NUM> or the common camera 7a may keep capturing the image of the scene in the range of the field of view at the predetermined frame rate during at least a period when the authentication target person T passes through the trigger point P1. As a result, even when the iris authentication system <NUM> is not provided with the human detection sensor <NUM>, the wide camera <NUM> or the common camera 7a is able to capture the image of the authentication target person T at a timing when the authentication target person T reaches the trigger point P1. Namely, even when the iris authentication system <NUM> is not provided with the human detection sensor <NUM>, the image obtaining unit <NUM> is able to obtain the wide image <NUM> including the authentication target person T located at the trigger point P1.

When the iris authentication system <NUM> is not provided with the human detection sensor <NUM>, the iris authentication apparatus <NUM> (for example, the area detection unit <NUM>) may determine whether or not the wide image <NUM> including the authentication target person T located at the trigger point P1 is obtained by performing an image analysis on the wide image <NUM>. Namely, the iris authentication apparatus <NUM> may determine whether or not the authentication target person T is located at the trigger point P1 by performing the image analysis on the wide image <NUM>. When it is determined that the authentication target person T is located at the trigger point P1 (namely, the wide image <NUM> including the authentication target person T located at the trigger point P1 is obtained), the iris authentication apparatus <NUM> performs the process of selecting one iris camera <NUM> for capturing the image of the authentication target person T located at the focus point P2 (specifically, a series of processes from the step S21 to the step S32 of <FIG> or <FIG>) on the basis of the wide image <NUM>. On the other hand, when it is determined that the authentication target person T is not located at the trigger point P1, the iris authentication apparatus <NUM> does not start a series of processes from the step S21 to the step S32 of <FIG> or <FIG>. Note that the iris authentication apparatus <NUM> may use an existing method as a method for the image analysis for determining whether or not the authentication target person T is located at the trigger point P1. For example, the iris authentication apparatus <NUM> may determine whether or not the authentication target person T is located at the trigger point P1 by estimating a depth from the wide image <NUM>. For example, the iris authentication apparatus <NUM> may determine whether or not the authentication target person T is located at the trigger point P1 by detecting a foot of the authentication target person T included in the wide image <NUM> and determining whether or not the detected foot is located at the trigger point P1. For example, the iris authentication apparatus <NUM> may determine whether or not the authentication target person T is located at the trigger point P1 by determining whether or not an interval between both eyes of the authentication target person T included in the wide image <NUM> is a predetermined value.

In the above described description, the iris authentication system <NUM> is provided with the human detection sensor <NUM>. However, the iris authentication system <NUM> may not be provided with the human detection sensor <NUM>. In this case, the iris camera <NUM> on which the region of interest IA is already set may keep capturing the image of the scene in the range of the field of view at a predetermined frame rate (namely, an imaging rate) regardless of whether the authentication target person T is located at the focus point P2 after the region of interest IA of the iris camera <NUM> is set at the step S32 of <FIG>. Alternatively, the common camera 7a on which the region of interest IA is already set may keep capturing the image of the scene in the range of the field of view at a predetermined frame rate (namely, an imaging rate) regardless of whether the authentication target person T is located at the focus point P2 after the region of interest IA of the common camera 7a is set at the step S32a of <FIG>. Typically, the iris camera <NUM> or the common camera 7a may keep capturing the image of the scene in the range of the field of view at the predetermined frame rate (namely, the imaging rate) during at least a period when the authentication target person T passes through the focus point P2. As a result, even when the iris authentication system <NUM> is not provided with the human detection sensor <NUM>, the iris camera <NUM> or the common camera 7a is able to capture the image of the authentication target person T at a timing when the authentication target person T reaches the focus point P2 from the trigger point P1. Namely, even when the iris authentication system <NUM> is not provided with the human detection sensor <NUM>, the image obtaining unit <NUM> is able to obtain the iris image <NUM> including the authentication target person T located at the focus point P2.

In the above described description, the example embodiment of the imaging system, the imaging method, the control apparatus, the computer program and the recording medium is applied to the iris authentication system <NUM>. However, the example embodiment of the imaging system, the imaging method, the control apparatus, the computer program and the recording medium may be applied to any authentication system that performs an authentication of the authentication target person T on the basis of a feature of a predetermined part of the authentication target person T that is different from the iris. Namely, the iris authentication system <NUM> may be modified to be any authentication system that performs any authentication operation. A face authentication system that performs the authentication of the authentication target person T on the basis of a feature of a face of the authentication target person T is one example of any authentication system. Alternatively, the example embodiment of the imaging system, the imaging method, the control apparatus, the computer program and the recording medium may be applied to any imaging system that controls the iris camera <NUM> (alternatively, a second imaging apparatus) to capture an image of a moving imaging target person on the basis of an image of the imaging target person captured by the wide camera <NUM> (alternatively, a first imaging apparatus). Namely, the iris authentication system <NUM> may be modified to be any imaging system that captures the image of the imaging target person at the above described trigger point P1 and the focus point P2 by using at least two types of imaging apparatuses, respectively.

Claim 1:
An imaging system comprising:
a first imaging apparatus that captures an image of an imaging target that is located at a first point located on a moving route of the imaging target;
a second imaging apparatus a focus position of which is set at a second point that is located at a forward side along a moving direction of the imaging target than the first point; and
a control apparatus that controls the second imaging apparatus to capture an image of the imaging target that is located at the second point on the basis of the image captured by the first imaging apparatus, wherein
the control apparatus (i) determines, on the basis of the image captured by the first imaging apparatus, a first position coordinate that is a position coordinate of the imaging target located at the first point in the image captured by the first imaging apparatus, (ii) estimates, on the basis of the first position coordinate, a second position coordinate that is a position coordinate of the imaging target in the image captured by the second imaging apparatus under the assumption that the second imaging apparatus has captured the image of the imaging target that has moved from the first point to the second point, and (iii) controls, on the basis of the second position coordinate, the second imaging apparatus to capture the image of the imaging target that is located at the second point.