Patent Description:
For example, <CIT> describes a data acquisition apparatus that can prevent registration of feature data that is unsuitable for identity determination. This data acquisition apparatus includes an acquisition unit for acquiring feature data indicative of features distributed in a region of a predetermined size on an object to be registered from an image including the object and verification unit for verifying that reliability of the feature data acquired by the acquisition unit is equal to or higher than a predetermined reference value on the basis of a result of matching between a part of the feature data acquired by the acquisition unit and data acquired from a corresponding region of the feature data and a result of matching between a part of feature data acquired from a different object and data acquired from a corresponding region of the feature data acquired by the acquisition unit. <CIT> discloses a registering apparatus including: a first image data acquiring unit that acquires first image data from a first region on a recording medium; a second image data acquiring unit that acquires second image data from a second region that includes the first region; a third image data acquiring unit that acquires third image data from a third region that does not include the first region and differs from the second region when a correlation value between the second image data and the first image data is equal to or greater than a predetermined first threshold value; and a registering unit that registers the first image data as registration data that are image data to be used in authentication of the recording medium when a correlation value between the third image data and the first image data is equal to or less than a second threshold value.

<CIT> discloses a convolutional neural network training method, a system of image processing, and corresponding computer equipment.

<CIT> discloses a method of creating a tag, the method including: reading, over a first region of a surface of an individual piece, a characteristic having randomness distributed over the surface of the individual piece and converting image information indicative of the read characteristic of the first region into individual piece information peculiar to the individual piece; forming an individual piece information image indicative of the individual piece information on the surface of the individual piece while using a second region having a predetermined range including the first region as a non-image forming region; and creating the tag, which is to be affixed to an article, from the individual piece.

In a system such as a system for determining authenticity of an object, authenticity is determined by imaging a random pattern on a surface of an object and then comparing a registered image of the random pattern thus obtained and a comparison image.

In a case where an image is registered as a registered image, whether or not the target image is suitable as a registered image is determined by acquiring plural images of corresponding regions of plural different objects and comparing the plural images thus acquired. Accordingly, a lot of man-hours are required for registration of a registered image.

Accordingly, it is an object of the present disclosure to provide an information processing apparatus, a program, and an information processing method that can reduce man-hours for registration of a registered image in a case where an image showing a random pattern on a surface of an object to be registered is registered as a registered image, as compared with a case where plural images acquired from plural different objects are used.

Exemplary embodiments of the technique of the present disclosure will be described in detail below with reference to the drawings. Note that constituent elements and processes that are identical in terms of operation, action, or function are given identical reference signs throughout the drawings, and repeated description thereof is omitted as suitable. The drawings merely schematically illustrate the technique of the present disclosure to such a degree that the technique of the present disclosure is fully understood. Therefore, the technique of the present disclosure is not limited to illustrated examples. Furthermore, in the present exemplary embodiment, description of constituent elements that are not directly related to the present disclosure and well-known constituent elements is omitted in some cases.

Although a case where authenticity is determined by using an image of a random pattern of an object is described below in the exemplary embodiments, a target of application is not limited to determination of authenticity and can be, for example, object recognition.

<FIG> is a diagram illustrating an example of a configuration of an authenticity determining system <NUM> according to a first exemplary embodiment.

As illustrated in <FIG>, the authenticity determining system <NUM> according to the present exemplary embodiment registers in advance an image of a region (e.g., <NUM> square region) of a surface of an object as information unique to the object, compares an image of a target object with the registered image of the object, and uniquely determines that these objects are identical in a case where the compared images are similar. Note that determining whether or not a registered image and a comparison image are identical is referred to as authenticity determination.

As the information unique to the object, for example, a random pattern that is difficult to form under control, such as a distribution of plant fibers forming paper or a state of dispersion of metal fine particles contained in silver paint, is applied. The random pattern is a pattern on a surface of an object unique to the object and having fine irregular features that cannot be reproduced. The random pattern is, for example, observed from a surface of nonwoven fabric, paper, or carbon-filled black rubber, a surface of a ceramic for an integrated circuit (IC) package, a surface of an ultraviolet curable coating (lame coating) in which metal fine particles are dispersed, or the like. The random pattern is, for example, also observed from a surface of a stainless steel material that has been, for example, hair-line finished or sandblasted, a surface of a leather having random wrinkles in a natural state, or the like.

In the authenticity determining system <NUM>, such a random pattern is optically read and is used as information. An image showing a fine random pattern is taken by using an imaging device such as a smartphone, a digital camera, or a scanner.

The authenticity determining system <NUM> illustrated in <FIG> includes an information processing apparatus <NUM>, an imaging device <NUM>, and an imaging device <NUM>. The imaging device <NUM> images a random pattern on a surface of an object <NUM> to be registered. The imaging device <NUM> images a random pattern on a surface of an object <NUM> to be compared. The information processing apparatus <NUM> causes an image showing the random pattern obtained by imaging the surface of the object <NUM> by the imaging device <NUM> to be registered as a registered image in a database (not illustrated) in advance. Meanwhile, the information processing apparatus <NUM> acquires, as a comparison image, an image showing the random pattern obtained by imaging the surface of the object <NUM> by the imaging device <NUM>. The information processing apparatus <NUM> compares the comparison image whose authenticity is to be determined with the registered image registered in advance in the database. Specifically, the information processing apparatus <NUM> finds features of the registered image and features of the comparison image and calculates a similarity between the registered image and the comparison image from the features thus found. In a case where the similarity is equal to or higher than a certain value, the information processing apparatus <NUM> determines that the registered image and the comparison image are images read from an identical object, that is, the object <NUM> is identical to the object <NUM>.

The authenticity determining system <NUM> is, for example, applied to a case where whether a security handled at a window of a financial institution is a genuine one (true object) legitimately printed or a false one (determination of authenticity of a security or the like) or a case where whether a pill prepared at a pharmacy is a genuine one (true object) legitimately produced or a false one (determination of authenticity of a pill).

<FIG> is a block diagram illustrating an example of an electric configuration of the information processing apparatus <NUM> according to the first exemplary embodiment.

As illustrated in <FIG>, the information processing apparatus <NUM> according to the present exemplary embodiment includes a central processing unit (CPU) <NUM>, a read only memory (ROM) <NUM>, a random access memory (RAM) <NUM>, an input/output interface (I/O) <NUM>, a storage unit <NUM>, a display unit <NUM>, an operation unit <NUM>, and a communication unit <NUM>.

As the information processing apparatus <NUM> according to the present exemplary embodiment, a general computer apparatus such as a server computer or a personal computer (PC) is applied, for example.

The CPU <NUM>, the ROM <NUM>, the RAM <NUM>, and the I/O <NUM> are connected to one another through a bus. The I/O <NUM> is connected to functional units including the storage unit <NUM>, the display unit <NUM>, the operation unit <NUM>, and the communication unit <NUM>. These functional units are communicable with the CPU <NUM> via the I/O <NUM>.

The CPU <NUM>, the ROM <NUM>, the RAM <NUM>, and the I/O <NUM> constitute a controller. The controller may be configured as a sub controller that controls operation of a part of the information processing apparatus <NUM> or may be configured as a part of a main controller that controls operation of the whole information processing apparatus <NUM>. As one or more of the blocks of the controller, an integrated circuit such as a large scale integration (LSI) or an integrated circuit (IC) chip set is used. Individual circuits may be used as the blocks or a circuit on which some or all of the blocks are integrated may be used. The blocks may be integral with one another or there may be a block that is separately provided. Furthermore, each of the blocks may have a part that is separately provided. Integration of the controller is not limited to LSI and may be realized by a dedicated circuit or a general-purpose processor.

As the storage unit <NUM>, a hard disk drive (HDD), a solid state drive (SSD), a flash memory, or the like is used, for example. In the storage unit <NUM>, an information processing program 15A for performing image registration processing according to the present exemplary embodiment is stored. Note that the information processing program 15A may be stored in the ROM <NUM>.

The information processing program 15A may be, for example, installed in advance in the information processing apparatus <NUM>. The information processing program 15A may be stored in a non-volatile recording medium or distributed over a network, and this information processing program 15A may be installed in the information processing apparatus <NUM> as suitable. Note that assumed examples of the non-volatile recording medium include a compact disc read only memory (CD-ROM), a magnetooptical disc, an HDD, a digital versatile disc read only memory (DVD-ROM), a flash memory, and a memory card.

As the display unit <NUM>, a liquid crystal display (LCD), an organic EL (electro luminescence) display, or the like is used, for example. The display unit <NUM> may have a touch panel as a part thereof. As the operation unit <NUM>, a device for entry of an operation such as a keyboard or a mouse is provided, for example. The display unit <NUM> and the operation unit <NUM> receive various kinds of instructions from a user of the information processing apparatus <NUM>. The display unit <NUM> displays a result of processing performed in response to an instruction received from the user and various kinds of information such as a notification concerning processing.

The communication unit <NUM> is connected to the network such as the internet, a local area network (LAN), or a wide area network (WAN) and is communicable with an external device such as the imaging device <NUM>, the imaging device <NUM>, and an image forming apparatus over the network.

In a case where an image is registered as a registered image as described above, plural images are acquired by imaging corresponding regions of plural different objects, and it is determined whether or not a target image is suitable as a registered image is determined by comparing the acquired plural images. This requires a lot of man-hours for registration of a registered image.

The information processing apparatus <NUM> according to the present exemplary embodiment extracts a first region of a predetermined size showing a feature of the object <NUM> to be registered from an image of the object <NUM>, specifies, from the image, a second region to be compared with the first region and having the same size as the first region, calculates a similarity between the first region and the second region, and registers an image of the first region as a registered image in a case where the similarity satisfies a predetermined standard.

Specifically, the CPU <NUM> of the information processing apparatus <NUM> according to the present exemplary embodiment writes the information processing program 15A stored in the storage unit <NUM> into the RAM <NUM> and executes the information processing program 15A, and thus functions as the units illustrated in <FIG>. Note that the CPU <NUM> is an example of a processor.

<FIG> is a block diagram illustrating an example of a functional configuration of the information processing apparatus <NUM> according to the first exemplary embodiment.

As illustrated in <FIG>, the CPU <NUM> of the information processing apparatus <NUM> according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E.

In the storage unit <NUM> according to the present exemplary embodiment, a threshold value database (hereinafter referred to as a "threshold value DB") 15B and a registered image database (hereinafter referred to as a "registered image DB") 15C are stored. The threshold value DB 15B may be stored in an external storage device that can be accessed. In the threshold value DB 15B, various threshold values for determining whether or not to register, as a registered image, a region extracted from an image of the object <NUM> are registered. In the registered image DB 15C, a registered image is registered.

The acquisition unit 11A acquires an image (hereinafter referred to as an "object surface image") obtained by imaging a surface of the object <NUM> by the imaging device <NUM>. The object surface image is an image showing a random pattern described above. Note that the imaging device <NUM> may image plural different positions of the object <NUM> or may image only a single position of the object <NUM>. Only a single imaging device <NUM> may be provided or plural imaging devices <NUM> may be provided. The imaging device <NUM> may take plural images for a single imaging position. In a case where the imaging device <NUM> images plural different positions, plural images are acquired for each of the plural imaging positions.

The extraction unit 11B extracts a first region from the object surface image acquired by the acquisition unit 11A. The first region is a region of a predetermined size showing a feature of the object <NUM>. For example, in a case where the first region is a rectangular region, the first region is a region that is <NUM> or more and <NUM> or less on a side. Note that a length of one side is not limited to <NUM> or more and <NUM> or less.

The specifying unit 11C specifies a second region from the object surface image acquired by the acquisition unit 11A. The second region is a region to be compared with the first region and having the same size as the first region. Note that a part of the second region may overlap a part of the first region. A specific method for acquiring the first region and the second region from the object surface image is described below with reference to <FIG>.

<FIG> is a view for explaining a method for acquiring a first region <NUM> and a second region <NUM> from an object surface image <NUM> according to the first exemplary embodiment.

As illustrated in <FIG>, the extraction unit 11B extracts a third region <NUM> from the object surface image <NUM>. The third region <NUM> is a region including the first region <NUM> and having a larger size than the first region <NUM>. The third region <NUM> has, for example, a size of <NUM> pixels × <NUM> pixels, and the first region <NUM> has, for example, a size of <NUM> pixels × <NUM> pixels. Note that the third region <NUM> may have a size of <NUM> pixels × <NUM> pixels, and the first region <NUM> may have a size of <NUM> pixels × <NUM> pixels.

The specifying unit 11C specifies, as the second region <NUM>, at least a part of the third region <NUM> other than the first region <NUM>. The second region <NUM> is a region located around the first region <NUM>. A single second region <NUM> may be extracted or plural second regions <NUM> may be extracted. The second region <NUM> has the same size as the first region <NUM> and has, for example, a size of <NUM> pixels × <NUM> pixels.

The deriving unit 11D derives a similarity between the first region <NUM> and the second region <NUM>. The similarity is, for example, expressed as a cross-correlation value between the first region <NUM> and the second region <NUM>. A cross-correlation value RNCC is derived by using the following formula (<NUM>) where fn (n = <NUM> to N) is a pixel value of each pixel included in the first region <NUM>, N (for example, N = <NUM> × <NUM> = <NUM>) is a total number of pixels of the first region <NUM>, gn (n = <NUM> to N) is a pixel value of each pixel included in the second region <NUM>, and N (for example, N = <NUM> × <NUM> = <NUM>) is a total number of pixels of the second region <NUM>.

Furthermore, a cross-correlation value RZNCC is derived by using the following formula (<NUM>) where fn (n = <NUM> to N) is a pixel value of each pixel included in the first region <NUM>, N (for example, N = <NUM> × <NUM> = <NUM>) is a total number of pixels of the first region <NUM>, fAVE is an average of the pixel values of the pixels included in the first region <NUM>, gn (n = <NUM> to N) is a pixel value of each pixel included in the second region <NUM>, N (for example, N = <NUM> × <NUM> = <NUM>) is a total number of pixels of the second region <NUM>, and gAVE is an average of the pixel values of the pixels included in the second region <NUM>.

Either the cross-correlation value RNCC derived by the formula (<NUM>) or the cross-correlation value RZNCC derived by the formula (<NUM>) may be employed as the similarity between the first region <NUM> and the second region <NUM>. In a case where plural second regions <NUM> are extracted, this similarity is derived for each of the plural second regions <NUM>.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in the registered image DB 15C in a case where the similarity derived by the deriving unit 11D satisfies a predetermined standard. Specifically, in a case where the similarity is equal to or less than a threshold value, the registration unit 11E registers the image of the first region <NUM> as a registered image. An appropriate value is set in advance as the threshold value concerning the similarity by a user (e.g., a system provider or a system designer) and is stored in the threshold value DB 15B. In the present exemplary embodiment, in a case where the first region <NUM> and the second region <NUM> located around the first region <NUM> that are obtained from the same object (the object <NUM>) are not similar, it is regarded that randomness is high, and it is determined that the image of the first region <NUM> is suitable as a registered image. Note that in a case where plural second regions <NUM> are extracted, the registration unit 11E registers, as a registered image, the image of the first region <NUM> in a case where similarities between the first region <NUM> and the plural second regions <NUM> are equal to or less than the threshold value. Furthermore, an image of the second region <NUM> may be registered as a registered image in addition to the image of the first region <NUM>. Furthermore, the image of the first region <NUM> may be acquired as a comparison image.

Next, operation of the information processing apparatus <NUM> according to the first exemplary embodiment is described with reference to <FIG>.

<FIG> is a flowchart illustrating an example of a flow of processing of the information processing program 15A according to the first exemplary embodiment.

First, when the information processing apparatus <NUM> is instructed to perform image registration processing, the information processing program 15A is activated by the CPU <NUM>, and the following steps are performed.

In step S101 of <FIG>, for example, the CPU <NUM> acquires the object surface image <NUM> of the object <NUM> to be registered, as illustrated in <FIG>.

In step S102, for example, the CPU <NUM> extracts the first region <NUM> from the object surface image <NUM> acquired in step S101, as illustrated in <FIG>.

In step S103, for example, the CPU <NUM> extracts the third region <NUM> from the object surface image <NUM> acquired in step S101, as illustrated in <FIG>. The third region <NUM> is a region including the first region <NUM> and having a larger size than the first region <NUM>.

In step S104, for example, the CPU <NUM> specifies one or more second regions <NUM> from the third region <NUM> extracted in step S103, as illustrated in <FIG>. The second region <NUM> is at least a part of the third region <NUM> other than the first region <NUM>.

In step S105, the CPU <NUM> derives a similarity between the first region <NUM> extracted in step S102 and the second region <NUM> specified in step S104. The similarity is, for example, derived as a cross-correlation value by using either the formula (<NUM>) or the formula (<NUM>).

In step S106, the CPU <NUM> determines whether or not the similarity derived in step S105 satisfies a predetermined standard, that is, whether or not the similarity derived in step S105 is equal to or less than a threshold value. In a case where the CPU <NUM> determines that the similarity is equal to or less than the threshold value (a positive result is obtained), it is regarded that the image of the first region <NUM> is suitable as a registered image, and step S107 is performed. On the other hand, in a case where the CPU <NUM> determines that the similarity is larger than the threshold value (a negative result is obtained), it is regarded that the image of the first region <NUM> is not suitable as a registered image, and the series of processing of the information processing program 15A are finished.

In step S107, the CPU <NUM> registers, as a registered image, the image of the first region <NUM> in the registered image DB 15C, and the series of processing of the information processing program 15A are finished.

As described above, according to the present exemplary embodiment, a registered image is registered by using plural images of a single object. Accordingly, man-hours related to registration of a registered image are reduced as compared with a case where plural images of plural different objects are used.

Furthermore, not only suitability of a first region to be registered as a registered image, but also suitability of another region (a second region around the first region) as a registered image can be verified.

In the first exemplary embodiment, suitability as a registered image is verified by using a similarity between a first region and a second region. In the second exemplary embodiment, suitability as a registered image is verified by using a data characteristic of the first region in addition to the similarity.

<FIG> illustrates an example of a surface state of a first region <NUM> according to the second exemplary embodiment. In the example of <FIG>, a state where the surface of the first region <NUM> is "streaked" and a state where the surface of the first region <NUM> is "out of focus" are illustrated. Since an image including an out-of-focus part, a streak, a scratch, dust, or the like is unsuitable as a registered image, it is desirable to eliminate such an unsuitable image.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10A") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10A according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

The deriving unit 11D derives a similarity between the first region <NUM> and a second region <NUM> and further derives a characteristic value indicative of a characteristic of the first region <NUM> from the first region <NUM>.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where the similarity between the first region <NUM> and the second region <NUM> is equal to or less than a threshold value and the characteristic value of the first region <NUM> satisfies a predetermined condition. Specifically, the characteristic value is, for example, a compression rate, sharpness, a brightness distribution, a Hamming distance, or the like. The compression rate is a rate of decrease of a compressed image from an original image. Since an image of a relatively high compression rate tends to have low resolution, it is desirable to exclude such an image. In this case, in a case where the similarity is equal to or less than the threshold value and the compression rate of the first region <NUM> is equal to or less than a threshold value, the image of the first region <NUM> is registered as a registered image. The image of the first region <NUM> may be acquired as a comparison image. Note that the threshold value concerning the compression rate is stored in advance in a threshold value DB 15B.

The sharpness is one kind of index indicative of clarity of an image. Specifically, for example, dispersion (hereinafter referred to as Laplacian dispersion σ) of a contour image extracted from an image is found by using a Laplacian operator V and a Laplacian filter L expressed by the formula (<NUM>) below. The Laplacian dispersion σ is an index indicative of a degree of dispersion of pixel values. Note that the Laplacian filter L is a filter for extracting a contour from an image by using secondary differentiation.

Since an image of relatively low sharpness (e.g., Laplacian dispersion σ) tends to be an out-of-focus image, it is desirable to exclude such an image. In this case, in a case where the similarity is equal to or less than the threshold value and the sharpness of the first region <NUM> is equal to or more than a threshold value, the image of the first region <NUM> is registered as a registered image. Note that the threshold value concerning the sharpness is stored in advance in the threshold value DB 15B.

The brightness distribution is an index indicative of a distribution of brightness of an image. Specifically, kurtosis and skewness of an image are found. The kurtosis is an index indicative of sharpness of a distribution of pixel values, and the skewness is an index indicative of a degree of distortion of a distribution of pixel values. For example, skewness D is found by the following formula (<NUM>) where n is the number of pixels of an image, xi (i = <NUM>, <NUM>, <NUM>, <NUM>,. , and n) is a pixel value, x- (- is directly above x) is an average of the pixel values, and s is a standard deviation.

Since an image of relatively large skewness tends to be an image including a streak, a scratch, dust, or the like, it is desirable to exclude such an image. In this case, in a case where the similarity is equal to or less than the threshold value and skewness of the first region <NUM> is equal to or less than a threshold value, the image of the first region <NUM> is registered as a registered image. The threshold value concerning the skewness is stored in advance in the threshold value DB 15B.

The Hamming distance is the number of bits (digits) at which corresponding values (<NUM> or <NUM>) of two images are different. A Hamming distance between two images is derived. Since an image having a relatively small Hamming distance from another image tends to be similar to the other image, it is desirable to exclude such an image. In this case, in a case where the similarity is equal to or less than the threshold value and a Hamming distance between the first region <NUM> and the second region <NUM> is equal to or more than a threshold value, the image of the first region <NUM> is registered as a registered image. The threshold value concerning the Hamming distance is stored in advance in the threshold value DB 15B.

Note that in a case where plural second regions <NUM> are extracted, the image of the first region <NUM> is registered as a registered image in a case where similarities to the plural second regions <NUM> are equal to or less than the threshold value and the characteristic value satisfies a predetermined condition.

As described above, according to the present exemplary embodiment, an unsuitable image including an out-of-focus part, a streak, a scratch, dust, or the like among images regarded as being suitable as a registered image by using a similarity can be excluded.

In a third exemplary embodiment, suitability as a registered image is verified by using features indicative of a degree of distribution of similarities in addition to a similarity.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10B") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10B according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

<FIG> are views for explaining a method for deriving features indicative of a degree of distribution of similarities according to the third exemplary embodiment. <FIG> illustrates a first region <NUM> and a third region <NUM> extracted from an object surface image <NUM>, <FIG> illustrates region movement in the third region <NUM>, and <FIG> illustrates specified plural fourth regions <NUM>.

As illustrated in <FIG>, the extraction unit 11B extracts the third region <NUM> and the first region <NUM> from the object surface image <NUM>. As illustrated in <FIG>, the specifying unit 11C shifts a region <NUM> having the same size as the first region <NUM> in the third region <NUM> by one pixel at each time in a predetermined direction (a direction from left to right in the example of <FIG>) from a start end of the third region <NUM> until the region <NUM> moves to a terminal end of the third region <NUM>. As illustrated in <FIG>, plural regions <NUM> thus obtained are specified as plural fourth regions <NUM>. In the example of <FIG>, the plural fourth regions <NUM> are expressed as n regions f<NUM>,. Note that the fourth regions <NUM> may be different from a second region <NUM> or any one of the plural fourth regions <NUM> may be identical to the second region <NUM>.

The deriving unit 11D derives plural similarities between the first region <NUM> and the plural fourth regions <NUM> and derives features indicative of a degree of distribution of the similarities obtained for a maximum similarity among the plural similarities thus derived. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as a similarity. In a case where the number of fourth regions <NUM> is n, n cross-correlation values are obtained. As the features, a normalized score indicative of a degree of distribution of cross-correlation values obtained for a maximum cross-correlation value is used, for example. The normalized score is an index indicative of how far the value is away from a population average. That is, a normalized score of the maximum cross-correlation value is an index indicative of how far the maximum cross-correlation value is away from an average of the cross-correlation values. It can be said that a higher normalized score indicates higher randomness.

A normalized score NSi is derived by using the following formula (<NUM>) where Ri is a maximum cross-correlation value, R- (- is directly above R) is an average of cross-correlation values, and σ is a standard deviation of the cross-correlation values.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where a similarity between the first region <NUM> and the second region <NUM> is equal to or less than a threshold value and features (e.g., a normalized score) are equal to or more than a certain value. The image of the first region <NUM> may be acquired as a comparison image. Note that the certain value (threshold value) concerning the features is stored in advance in the threshold value DB 15B.

As described above, according to the present exemplary embodiment, a more suitable image of higher randomness among images regarded as being suitable as a registered image by using a similarity can be obtained as a registered image.

In a fourth exemplary embodiment, suitability as a registered image is verified by using a data characteristic of a first region and features indicative of a degree of distribution of similarities in addition to a similarity.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10C") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10C according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

As illustrated in <FIG>, the extraction unit 11B extracts a third region <NUM> and a first region <NUM> from an object surface image <NUM>. As illustrated in <FIG>, the specifying unit 11C shifts a region <NUM> having the same size as the first region <NUM> in the third region <NUM> by one pixel at each time in a predetermined direction (a direction from left to right in the example of <FIG>) from a start end of the third region <NUM> until the region <NUM> moves to a terminal end of the third region <NUM>. As illustrated in <FIG>, plural regions <NUM> thus obtained are specified as the plural fourth regions <NUM>. In the example of <FIG>, the plural fourth regions <NUM> are expressed as n regions f<NUM>,.

The deriving unit 11D derives plural similarities between the first region <NUM> and the plural fourth regions <NUM> and derives features indicative of a degree of distribution of the similarities obtained for a maximum similarity among the plural similarities thus derived. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as a similarity. In a case where the number of fourth regions <NUM> is n, n cross-correlation values are obtained. As the features, a normalized score derived by using the formula (<NUM>) described above is used, for example. The deriving unit 11D derives, for example, a characteristic value indicative of a characteristic of the first region <NUM> from the first region <NUM> by using the formula (<NUM>) or the formula (<NUM>) described above.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where a similarity between the first region <NUM> and the second region <NUM> is equal to or less than a threshold value, the features (e.g., a normalized score) are equal to or more than a certain value, and the characteristic value (e.g., a compression rate, Laplacian dispersion, or skewness) of the first region <NUM> satisfies a predetermined condition. The image of the first region <NUM> may be acquired as a comparison image.

As described above, according to the present exemplary embodiment, an unsuitable image including an out-of-focus part, a streak, a scratch, dust, or the like among images regarded as being suitable as a registered image by using a similarity can be excluded, and a more suitable image of higher randomness can be obtained as a registered image.

In a fifth exemplary embodiment, suitability as a registered image is verified by using only features indicative of a degree of distribution of similarities.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10D") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10D according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

<FIG> are views for explaining a method for deriving features indicative of a degree of distribution of similarities according to the fifth exemplary embodiment. <FIG> illustrates a first region <NUM> and a third region <NUM> extracted from an object surface image <NUM>, <FIG> illustrates region movement in the third region <NUM>, and <FIG> illustrates specified plural second regions <NUM>.

As illustrated in <FIG>, the extraction unit 11B extracts the third region <NUM> and the first region <NUM> from the object surface image <NUM>. As illustrated in <FIG>, the specifying unit 11C shifts a region <NUM> having the same size as the first region <NUM> in the third region <NUM> by one pixel at each time in a predetermined direction (a direction from left to right in the example of <FIG>) from a start end of the third region <NUM> until the region <NUM> moves to a terminal end of the third region <NUM>. As illustrated in <FIG>, plural regions <NUM> thus obtained are specified as the plural second regions <NUM>. In the example of <FIG>, the plural second regions <NUM> are expressed as n regions f<NUM>,.

The deriving unit 11D derives plural similarities between the first region <NUM> and the plural second regions <NUM> and derives features indicative of a degree of distribution of the similarities obtained for a maximum similarity among the plural similarities thus derived. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as a similarity. In a case where the number of second regions <NUM> is n, n cross-correlation values are obtained. As the features, a normalized score derived by using the formula (<NUM>) described above is used, for example.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where the features (e.g., a normalized score) are equal to or more than a certain value. The image of the first region <NUM> may be acquired as a comparison image. In the present exemplary embodiment, whether or not to register an image is determined by using only features (e.g., a normalized score) obtained from a similarity without using a similarity itself to determine whether or not to register an image.

As described above, according to the present exemplary embodiment, suitability as a registered image is verified by using only features obtained from a similarity. It is therefore possible to obtain a suitable image having high randomness as a registered image.

In a sixth exemplary embodiment, suitability as a registered image is verified by using features indicative of a degree of distribution of similarities and a data characteristic of a first region.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10E") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10E according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

The deriving unit 11D derives plural similarities between a first region <NUM> and plural second regions <NUM> and derives features indicative of a degree of distribution of the similarities obtained for a maximum similarity among the plural similarities thus derived. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as a similarity. In a case where the number of second regions <NUM> is n, n cross-correlation values are obtained. As the features, a normalized score derived by using the formula (<NUM>) described above is used, for example. The deriving unit 11D derives a characteristic value indicative of a characteristic of the first region <NUM> from the first region <NUM>, for example, by using the formula (<NUM>) or the formula (<NUM>) described above.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where the features (e.g., a normalized score) are equal to or more than a certain value and the characteristic value (e.g., a compression rate, Laplacian dispersion, or skewness) of the first region <NUM> satisfies a predetermined condition. The image of the first region <NUM> may be acquired as a comparison image. In the present exemplary embodiment, whether or not to register an image is determined by using features (e.g., a normalized score) obtained from a similarity and a data characteristic of the first region <NUM> without using a similarity itself to determine whether or not to register an image.

As described above, according to the present exemplary embodiment, suitability as a registered image is verified by using features obtained from a degree of distribution of similarities and a data characteristic of a first region. Accordingly, an unsuitable image including an out-of-focus part, a streak, a scratch, dust, or the like can be excluded, and a suitable image of higher randomness can be obtained as a registered image.

In a seventh exemplary embodiment, suitability as a registered image is verified by using a similarity between a first region and a second region obtained by adding predetermined distortion to the first region.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10F") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10F according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

<FIG> is a view for explaining a method for acquiring a first region <NUM> and a second region 42A according to the seventh exemplary embodiment.

As illustrated in <FIG>, the extraction unit 11B extracts the first region <NUM> from an object surface image <NUM>. The specifying unit 11C specifies, as the second region 42A, a region obtained by adding predetermined distortion to the first region <NUM>. The predetermined distortion includes, for example, at least one of rotation of the first region <NUM> by a predetermined angle, mirroring of the first region <NUM>, and filtering of the first region <NUM>. In the example of <FIG>, a region obtained by rotating (affine transformation) the first region <NUM> by a predetermined angle is specified as the second region 42A. The predetermined angle is, for example, an angle such as <NUM> degrees, <NUM> degrees, or <NUM> degrees in a clockwise direction about a center of the first region <NUM>. For example, when an image of a random pattern is rotated by a certain angle or more, the rotated image is recognized as a different image. It is therefore desirable to decide an angle by which a rotated image is recognized as a different image in advance by using a simulation image. Note that the angle is desirably decided in accordance with a kind of random pattern since the angle varies depending on the kind of random pattern such as a "satin-finished surface", an "ink printed surface", a "painted surface", or a "paper surface".

<FIG> illustrates an example of an image obtained by rotating an image according to the seventh exemplary embodiment. In the example of <FIG>, an image obtained by rotating an image (first image) of the first region <NUM>, for example, by <NUM> degrees is illustrated.

<FIG> illustrates an example of an image obtained by mirroring an image according to the seventh exemplary embodiment. In the example of <FIG>, an image obtained by mirroring an image (first image) of the first region <NUM> is illustrated.

<FIG> illustrates an example of an image obtained by filtering an image according to the seventh exemplary embodiment. In the example of <FIG>, an image obtained by filtering an image (first image) of the first region <NUM> is illustrated. The filtering may be high-pass filtering or may be low-pass filtering. In a case where a pixel value of an image of the first region <NUM> is used as a reference, it is desirable to perform filtering for changing the pixel value within a range of -<NUM>% or more and +<NUM>% or less (e.g., within a range of <NUM> or more and <NUM> or less in a case where the pixel value is <NUM>).

The deriving unit 11D derives a similarity between the first region <NUM> and the second region 42A. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as the similarity.

The registration unit 11E registers, as a registered image, the image of the first region <NUM> in a registered image DB 15C in a case where the similarity between the first region <NUM> and the second region 42A is equal to or less than a threshold value. The image of the first region <NUM> may be acquired as a comparison image. In the present exemplary embodiment, in a case where the first region <NUM> and the second region 42A obtained by rotating the first region <NUM>, which are obtained from an identical object (an object <NUM> to be registered), are not similar, it is regarded that randomness is high, and it is determined that the image of the first region <NUM> is suitable as a registered image. In a case where plural second regions 42A having different rotation angles are obtained, the image of the first region <NUM> is registered as a registered image in a case where a similarity to each of the plural second regions 42A is equal to or less than the threshold value. Furthermore, an image of the second region 42A may be registered as a registered image in addition to the image of the first region <NUM>.

As described above, according to the present exemplary embodiment, a registered image is registered by using an image obtained from an object surface image and a rotated image obtained by rotating the image. This reduces man-hours for registration of a registered image as compared with a case where plural images of plural different objects are used.

In an eighth exemplary embodiment, suitability as a registered image is verified by using a data characteristic of a first region in addition to a similarity between the first region and a second region obtained by adding predetermined distortion to the first region.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus <NUM>") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus <NUM> according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

As illustrated in <FIG>, the extraction unit 11B extracts a first region <NUM> from an object surface image <NUM>. The specifying unit 11C specifies, as a second region 42A, a region obtained by adding predetermined distortion to the first region <NUM> (e.g., rotating the first region <NUM> by a predetermined angle).

The deriving unit 11D derives a similarity between the first region <NUM> and the second region 42A. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as the similarity. The deriving unit 11D derives a characteristic value indicative of a characteristic of the first region <NUM> from the first region <NUM>, for example, by using the formula (<NUM>) or the formula (<NUM>) described above.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where the similarity between the first region <NUM> and the second region 42A is equal to or less than a threshold value and the characteristic value (e.g., a compression rate, Laplacian dispersion, or skewness) of the first region <NUM> satisfies a predetermined condition. The image of the first region <NUM> may be acquired as a comparison image.

Note that in a case where plural second regions 42A having different rotation angles are specified, the image of the first region <NUM> is registered as a registered image in a case where a similarity to each of the plural second regions 42A is equal to or less than the threshold value and the characteristic value satisfies the predetermined condition.

As described above, according to the present exemplary embodiment, an unsuitable image including an out-of-focus part, a streak, a scratch, dust, or the like among images regarded as being suitable as a registered image by using a similarity to a rotated image can be excluded.

In a ninth exemplary embodiment, suitability as a registered image is verified by using features indicative of a degree of distribution of similarities in addition to a similarity between a first region and a second region obtained by adding predetermined distortion to the first region.

As illustrated in <FIG>, the extraction unit 11B extracts a first region <NUM> from an object surface image <NUM>. The specifying unit 11C specifies, as a second region 42A, a region obtained by rotating the first region <NUM> by a predetermined angle.

As illustrated in <FIG>, the extraction unit 11B extracts a third region <NUM> including the first region <NUM> from the object surface image <NUM>. As illustrated in <FIG>, the specifying unit 11C shifts a region <NUM> having the same size as the first region <NUM> in the third region <NUM> by one pixel at each time in a predetermined direction (a direction from left to right in the example of <FIG>) from a start end of the third region <NUM> until the region <NUM> moves to a terminal end of the third region <NUM>. As illustrated in <FIG>, plural regions <NUM> thus obtained are specified as plural fourth regions <NUM>. In the example of <FIG>, the plural fourth regions <NUM> are expressed as n regions f<NUM>,.

The deriving unit 11D derives plural similarities between the first region <NUM> and the plural fourth regions <NUM> and derives features indicative of a degree of distribution of the similarities obtained for a maximum similarity among the plural similarities thus derived. Specifically, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as a similarity. In a case where the number of fourth regions <NUM> is n, n cross-correlation values are obtained. As the features, a normalized score derived by using the formula (<NUM>) described above is used, for example.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where a similarity to the second region 42A obtained by adding predetermined distortion to the first region <NUM> (e.g., rotating the first region <NUM> by a predetermined angle) is equal to or less than a threshold value and features (e.g., a normalized score) obtained from plural similarities to the plural fourth regions <NUM> are equal to or more than a certain value. The image of the first region <NUM> may be acquired as a comparison image.

As described above, according to the present exemplary embodiment, a more suitable image having high randomness among images regarded as being suitable as a registered image by using a similarity to a rotated image can be obtained as a registered image.

In a tenth exemplary embodiment, suitability as a registered image is verified by using a data characteristic of a first region and features indicative of a degree of distribution of similarities in addition to a similarity between the first region and a second region obtained by adding predetermined distortion to the first region.

A CPU <NUM> of an information processing apparatus (hereinafter referred to as an "information processing apparatus 10J") according to the present exemplary embodiment functions as an acquisition unit 11A, an extraction unit 11B, a specifying unit 11C, a deriving unit 11D, and a registration unit 11E, as with the information processing apparatus <NUM> described in the first exemplary embodiment. Differences of the information processing apparatus 10J according to the present exemplary embodiment from the information processing apparatus <NUM> according to the first exemplary embodiment are described below.

The deriving unit 11D derives plural similarities between the first region <NUM> and the plural fourth regions <NUM> and derives features indicative of a degree of distribution of similarities obtained for a maximum similarity among the plural similarities thus derived. Specifically, for example, a cross-correlation value derived by using the formula (<NUM>) or the formula (<NUM>) described above is used as a similarity. In a case where the number of fourth regions <NUM> is n, n cross-correlation values are obtained. As the features, a normalized score derived by using the formula (<NUM>) described above is used, for example.

The registration unit 11E registers, as a registered image, an image of the first region <NUM> in a registered image DB 15C in a case where a similarity to the second region 42A obtained by adding predetermined distortion to the first region <NUM> (e.g., rotating the first region <NUM> by a predetermined angle) is equal to or less than a threshold value, features (e.g., a normalized score) obtained from plural similarities to the plural fourth regions <NUM> are equal to or more than a certain value, and a characteristic value (e.g., a compression rate, Laplacian dispersion, or skewness) of the first region <NUM> satisfies a predetermined condition. The image of the first region <NUM> may be acquired as a comparison image.

As described above, according to the present exemplary embodiment, an unsuitable image including an out-of-focus part, a streak, a scratch, dust, or the like among images regarded as being suitable as a registered image by using a similarity to a rotated image can be excluded, and a more suitable image of higher randomness can be obtained as a registered image.

The information processing apparatuses according to the exemplary embodiments have been described above. The exemplary embodiments may be programs for causing a computer to execute functions of the information processing apparatuses. The embodiments may be non-transitory computer readable media storing the programs.

Furthermore, although a case where the processing according to the exemplary embodiments is realized by a software configuration by execution of a program by a computer has been described in the above exemplary embodiments, this is not restrictive. The exemplary embodiments may be, for example, realized by a hardware configuration or a combination of a hardware configuration and a software configuration.

Claim 1:
An information processing apparatus (<NUM>) comprising:
a processor (<NUM>) configured to:
extract a first region showing a feature of an object to be registered and having a predetermined size from an object surface image obtained by imaging a surface of the object;
specify, from the object surface image, a second region to be compared with the first region and having a same size as the first region;
derive a similarity between the first region and the second region; and
characterized in that the processor is further configured to:
extract a third region including the first region and having a larger size than the first region from the object surface image;
specify, as a plurality of second regions, a plurality of regions obtained by shifting a region having a same size as the first region in the third region by one pixel at each time in a predetermined direction from a start end of the third region until the region moves to a terminal end of the third region;
derive a plurality of similarities between the first region and the plurality of second regions;
derive features indicative of a degree of distribution of the similarities obtained for a maximum similarity among the plurality of similarities; and
register, as a registered image, the image of the first region in a case where the similarity between the first region and the second region is equal to or less than a threshold value and the features are equal to or more than a certain value; and
wherein the processor is further configured to determine an authenticity of a target object by comparing an image of the target object with the registered image.