JP2001145613A - Camera apparatus with range finding function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera apparatus with a range finding function capable of measuring a distance from a camera part to a pupil based on a photographed picture by the single camera part. SOLUTION: This apparatus has an AF camera part 1 for photographing a human face, a picture storage part 2 for temporarily storing face picture information based on a picture signal outputted from this part 1, an eye position detecting part 3 for detecting the positions of eyes in a face picture based on the face picture information and outputting eye position information, a pupil diameter measuring part 4 for measuring the pupil diameter of the eye based on the eye position information and the face picture information, a storage part 6 having information on corresponding relation between a measured pupil diameter and a distance from the camera part to the pupil in a real space, and a camera distance outputting part 5 for measuring a distance from the part 1 to the pupil in the real space based on the pupil diameter and the information on the corresponding relation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera device having a distance measuring function used for photographing a human face in a personal identification device using an iris and measuring a distance from a camera unit to the iris. is there.

[0002]

2. Description of the Related Art An apparatus for measuring the distance from a camera section to a subject based on an image of a human face photographed by a camera section (image pickup device) is disclosed in, for example, JP-A-60-168.
No. 303 and JP-A-60-168304. In the devices disclosed in these publications, the distance from the camera unit to the subject is measured using the difference between the positions of characteristic points such as eyes and nose obtained from the two camera units.

[0003]

However, in the above-described conventional method, two cameras are required for distance measurement, and there is a problem that the price of the apparatus is increased.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a camera unit to an iris based on an image taken by one camera unit. It is an object of the present invention to provide a camera device with a distance measuring function capable of measuring the distance of the camera.

[0005]

According to the present invention, there is provided a camera device having a distance measuring function, wherein a camera unit for photographing a human face and face image information based on an image signal output from the camera unit are temporarily stored. An image storage unit, an eye position detection unit that detects an eye position in a face image based on the face image information, and outputs eye position information, and an eye position based on the eye position information and the face image information. An iris diameter measuring unit for measuring the iris diameter, and having correspondence information between the iris diameter measured by the iris diameter measuring unit and the distance from the camera unit to the iris in real space, the iris diameter and the correspondence information And a distance measuring unit that measures the distance from the camera unit to the iris in the real space based on the distance.

Further, the camera device with a distance measuring function according to the present invention has an input unit for inputting personal identification information, and the distance measuring unit is provided for a plurality of pre-registered persons with respect to iris diameter and real space. The distance measurement unit has correspondence information with the distance from the camera unit to the iris, and the distance measurement unit is configured to use a camera unit in a real space based on the correspondence information selected according to the personal identification information input from the input unit. It can also be configured to measure the distance from to the iris. Further, if the correspondence information to be selected according to the personal identification information input from the input unit does not exist in the distance measurement unit, the distance measurement unit may determine the distance in the real space based on the predetermined correspondence information stored in advance. May be configured to measure the distance from the camera unit to the iris.

The measurement of the iris diameter by the iris diameter measuring unit is performed on the circumference of a first circle having a radius r centered on eye position coordinates (x ₀ , y ₀ ) output by the eye position detecting unit. The process of calculating the average luminance value Cb (r) of the pixels on the circumference of the second luminance circle (where α is a positive constant) of the average luminance value Ca (r) and the radius r + α of the pixel MIN_r ≦ r ≦
The processing is performed for a plurality of values of the radius r that satisfies MAX_r (where MIN_r is the lower limit of r in the iris diameter measurement processing and MAX_r is the upper limit of r in the iris diameter measurement processing), and Cb ( It may be performed by outputting the value of r when r) -Ca (r) reaches the maximum value as the iris diameter.

Further, the iris diameter in the iris diameter measuring unit is
Eye position coordinates output by the eye position detection unit
(X₀, Y₀) On the circumference of the first circle of radius r
Second circle of average luminance value Ca (r) of pixel and radius r + α
(Here, α is a positive constant.)
The processing for obtaining the average luminance value Cb (r) is defined as MIN_r ≦ r ≦
MAX_r (where MIN_r is used in the iris diameter measurement process)
MAX_r is the iris diameter measurement process
Is the upper limit of r. ) And MIN_P_i≤
P _i≤MAX_P_i(Where P_iIs inside the first circle
The average brightness value in a fixed area, MIN_P_iThe rainbow
P corresponding to the lower limit of the luminance of the color_iIs the lower limit of MA
X_P_iIs P corresponding to the upper limit of the luminance of the iris._iUpper limit
It is. ) And MIN_P_o≤P_o≤MAX_P_o(here
And P_oIs the average over a given area outside the first circle
Luminance value, MIN_P_oIs P_oIs the lower limit of
AX_P_oIs P_oIs the upper limit. )
Is performed for the radius r of Cb (r) −Ca (r).
To output the value of r when it becomes a large value as the iris diameter
Therefore, it may be performed.

The eye position coordinates output by the eye position detection section are (x ₀ , y ₀ ), and x is x ₀ −MAX_X ≦ x
≦ x ₀ + MAX_X (where MAX_X is a positive constant), and y is y ₀ −MAX_
When a plurality of values satisfying Y ≦ y ≦ y ₀ + MAX_Y (where MAX_Y is a positive constant), the measurement of the iris diameter in the iris diameter measurement unit uses the coordinates (x, y) as coordinates. The average luminance value Ca (x, y, r) of the pixels on the circumference of the first circle having the center radius r and the second circle having the radius r + α (where α is a positive constant). The processing for obtaining the average luminance value Cb (x, y, r) of the pixels on the circumference is defined as MIN_r ≦ r
≦ MAX_r (where MIN_r is the lower limit value of r in the iris diameter measurement process, and MAX_r is the upper limit value of r in the iris diameter measurement process). (X, y, r) -Ca (x,
It may be performed by outputting the value of r when y, r) reaches the maximum value as the iris diameter.

Further, the eye position output by the eye position detecting section is provided.
If the coordinates are (x₀, Y₀) Where x is x₀−MAX_X ≦ x
≤x₀+ MAX_X (where MAX_X is a positive constant
is there. ), Where y is y₀−MAX_
Y ≦ y ≦ y₀+ MAX_Y (where MAX_Y is a positive
Is a constant. ) When there are multiple values that satisfy the rainbow
The measurement of the iris diameter in the iris diameter measurement unit is performed using coordinates (x, y).
Average luminance of pixels on the circumference of the first circle with radius r as the center
Value Ca (x, y, r) and a second circle of radius r + α (here
Where α is a positive constant. ) Average brightness of pixels on the circumference of
The process of obtaining the value Cb (x, y, r) is defined as MIN_r ≦ r
≤MAX_r (where MIN_r is the iris diameter measurement process
MAX_r is the lower limit value of r in the iris diameter measurement process.
This is the upper limit of r in theory. ) And MIN_P_i
≤P_i≤MAX_P_i(Where P_iIs inside the first circle
Average luminance value in a predetermined area, MIN_P_iIs
P corresponding to the lower limit of the luminance of the iris_iIs the lower limit of
AX_P_iIs P corresponding to the upper limit of the luminance of the iris._iUpper limit
Value. ) And MIN_P_o≤P_o≤MAX_P_o(here
And P_oIs the average over a given area outside the first circle
Luminance value, MIN_P _oIs P_oIs the lower limit of
AX_P_oIs P_oIs the upper limit. )
For a radius r of Cb (x, y, r) -Ca
The value of r when (x, y, r) reaches the maximum value is defined as the iris diameter.
Alternatively, the output may be performed.

The camera section is preferably an electronic camera of an autofocus type (for example, a CCD camera or a CMOS camera).

The distance measuring section stores a correspondence table based on a result of previously measuring the correspondence between the diameter of the iris measured by the iris diameter measuring section and the distance from the camera section to the iris in real space. The correspondence table may be used to measure the distance from the camera unit to the iris in the real space.

Further, the distance measuring section calculates the correspondence between the diameter of the iris measured by the iris diameter measuring section and the distance from the camera section to the iris in real space by a relational expression based on the result of actual measurement in advance. The distance from the camera unit to the iris in the real space may be measured using this relational expression.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a block diagram showing a configuration of a camera device 10 with a distance measuring function according to a first embodiment of the present invention. FIG.
3 is a sketch of a situation where the face 21 of the person 20 is being photographed by the camera device 10 of FIG. FIG. 3 shows the human eye 2
FIG. 3 is an enlarged view showing a pupil 23, an iris 24, and a sclera 25 of the second eyeball. FIG. 4 is a diagram illustrating an example of a one-frame face image captured by the camera unit 1 of FIG. 1 and stored in the image storage unit 2.

The camera device 10 with a distance measuring function is used for measuring the distance to the iris, for example, in a personal identification device using the iris. The distance information obtained by the camera device 10 with the distance measurement function is, for example, a narrow-angle camera device (a camera device (not shown) different from the wide-angle camera device 10 with the distance measurement function) that obtains an image for iris recognition. Adjustment (coarse adjustment) in a narrow-angle camera device
Used for In this case, fine adjustment of focus in the narrow-angle camera device is performed by an auto-focus mechanism (not shown) provided in the narrow-angle camera device after coarse adjustment.

As shown in FIG. 1, a camera device 10 with a distance measuring function has a camera unit (AF camera unit) 1 with an autofocus function for photographing a human face, and outputs from the AF camera unit 1. face image information (e.g., one frame of face image information as shown in FIG. 4) based on the image signals S ₁ and having an image storage unit 2 for temporarily storing. Further, the camera device 10 with the distance measurement function detects the position of the eye in the face image based on the face image information, and outputs the eye position information to the eye position detection unit 3 based on the eye position information and the face image information. Iris diameter measuring unit 4 for measuring the radius (iris diameter) of the iris of the eye in the face image (iris diameter r in the face image in FIG. 4), and the iris diameter r measured by the iris diameter measuring unit 4 and the real space AF camera unit 1 above
Iris diameter / camera distance correspondence table storage unit 6 having a correspondence table with the distance from the camera to the iris (distance D in FIG. 2), and an AF in real space based on the iris diameter and the correspondence table
A camera distance output unit 5 that outputs a distance from the camera unit 1 to the iris. In FIG. 1, reference numeral 7 denotes a proximity sensor that detects a person approaching.

The AF camera section 1 is, for example, a CCD camera having an autofocus function for photographing a human face. When the face as the subject is in focus, digitized image signals S ₁ are sequentially output from the AF camera unit 1 and input to the image storage unit 2.

The image storage unit 2 stores the input image signal S _1.
Is a storage element for temporarily storing one frame of face image information corresponding to. When an image signal for one frame is input to the image storage unit 2, an image signal S ₂ based on face image information for one frame is output from the image storage unit 2 to the eye position detection unit 3, iris diameter measurement unit 4, and Output to the outside.

The eye position detector 3 receives the input image signal S
It is a processing unit that determines the presence / absence of a face from ₂ , and when it is determined that a face is present, detects the position of the eye in the image. The processing of the eye position detecting unit 3 is known. For example, a face area is specified by using skin color information in image data, a filtering process is performed on the image data by an edge detection filter, and the image data is further processed by an appropriate threshold value. The image is binarized to generate a binarized edge image, each pixel of the image is projected in each of the x-axis direction and the y-axis direction, and the position of each face part is determined based on the obtained projection histogram. In this processing, an image reduced by reducing the resolution of the face image to や or ４ may be used in order to reduce the processing load. In that case, it is necessary to restore the coordinates of the eye position. Also,
The eye position information to be detected may be information on both the left and right eyes or information on one eye, and may be determined based on various factors such as the application and required accuracy. Further, the eye position detection method by the eye position detection unit 3 may be another method as long as the method detects the position coordinates of the eye.

The iris diameter measuring section 4 obtains the iris diameter r in the face image based on the eye position signal S ₃ output from the eye position detecting section 3. The iris diameter r is output as a signal S ₄ indicating the iris diameter information to the camera distance output section 6.

The iris diameter / camera distance correspondence table storage unit 6 is a memory that stores the relationship between the iris diameter r on the image shown in FIG. 4 and the camera distance D shown in FIG. As a method of creating this correspondence table, a model whose iris diameter is R in real space is photographed at various camera distances D, and the relationship between the iris diameter r and the camera distance D in the photographed image is obtained. To create a correspondence table. In other words, in the first embodiment, focusing on the fact that the individual difference of the iris diameter in the real space of the human eye is relatively small, the iris diameter in the real space is regarded as a constant value R, and the iris in the real space is considered. A correspondence table indicating the relationship between the iris diameter r and the camera distance D on the image when the model having the diameter R is captured is stored in the memory. Camera distance output section 5 based on the signal S ₄ about the iris diameter r of the input image, call the value of the camera distance D from a correspondence table stored in the iris diameter camera distance correspondence table storage unit 6, a camera and outputs the distance information signal S _5. Note that, instead of the iris diameter / camera distance correspondence table storage unit 6, the iris diameter r measured by the iris diameter measurement unit 4 and the distance D from the camera unit 1 to the iris in real space.
And a calculation unit based on a relational expression based on a result of previously measuring the correspondence between the camera unit 1 and the iris in the real space based on the measured iris diameter r. May be configured.

FIG. 5 shows a camera device 10 having a distance measuring function.
6 is a flowchart showing the operation of the embodiment. As shown in FIG. 5, when the processing in the camera device 10 with a distance measurement function is started (P101), the proximity sensor 7 is activated (P102). Next, when a person is detected by the proximity sensor 7 (P103), the AF camera unit 1 automatically adjusts the lens focus so as to focus on the face and photographs the face (P104). The captured image is stored in the image storage unit 2
Is temporarily stored as face image information, and the process is performed by the eye position detection unit 3 (P105). Here, the presence / absence of a face in the image and the eye position are detected from the face image information stored in the image storage unit 2. If it is determined that the face does not exist or if the eye position cannot be detected, the detection process (P
Return to 103).

Next, the processing by the iris diameter measuring section 4 is performed (P106). Here calculates the iris diameter r of the face image stored on the basis of the signal S ₃ about the eye position information obtained in the previous eye position detecting unit 3 in the image storage unit 2. If the iris diameter r cannot be measured, for example, because the iris cannot be found, the proximity sensor 7 detects a person (P10).
Return to 3).

Next, the processing in the camera distance output section 6 is performed (P107). Here, the process of calling the value of the camera distance D from the iris diameter / camera distance correspondence notation unit 6 based on the iris diameter information S ₄ obtained by the processing in the iris diameter measurement unit 4 described above.

[0025] Finally, and outputs a signal S ₂ based on the face image information stored in the camera distance signal S ₅ and the image memory 2 corresponding to the distance from the AF camera unit 1 to the iris to the outside (P108), A series of processing ends (P109). still,
The above processing may be performed only on either the left or right iris, but may be performed on both the left and right irises, and the camera distance may be obtained using the average value of the left and right iris diameters.

FIG. 6 is a flowchart showing the operation of the iris diameter measuring section 4 in detail. The iris diameter measuring unit 4 determines the center and radius (iris diameter) of the iris by fitting a circle (hereinafter referred to as an “iris circle”) based on the eye position obtained by the eye position detecting unit 3. FIG. 7 is a diagram showing iris circles A and B used for measuring the iris diameter, and FIG. 8 shows an inner region I and an outer region O of the iris circle A used for measuring the iris diameter. FIG.

In FIG. 6, the center coordinates (x,
y) is obtained by converting the eye position coordinates (x ₀ ,
y ₀ ) and in the x direction from −MAX_X to + MAX_
In the range up to X (here, MAX_X is a positive constant), that is, in the range of x ₀ −MAX_X ≦ x ≦ x ₀ + MAX_X, change by a small value dx (dx is a positive constant), and y
In the direction, a range from −MAX_Y to + MAX_Y (where MAX_Y is a positive constant), that is, y ₀ −M
In the range of AX_Y ≦ y ≦ y ₀ + MAX_Y, a minute value dy (d
(y is a positive constant). In FIG. 6, the radius of the iris circle A (finally, the radius of the iris circle A is
It becomes the iris diameter. A description will be given of a case where r is changed by a small value dr in a range from MIN_r to MAX_r (here, MIN_r and MAX_r are positive constants), that is, in a range of MIN_r ≦ r ≦ MAX_r.

As shown in FIG. 6, when the processing of the iris diameter measuring section 4 is started (P201), the evaluation value ma of the iris circle is obtained.
x_dC is initialized to 0 (P202). In the subsequent processing, the evaluation value max_dC includes the radius r shown in FIG.
The difference value between the average luminance value Cb of the pixels on the circumference of the circle B of + α (where α is a positive constant) and the average luminance value Ca of the pixels on the circumference of the iris circle A having a radius r. The largest one is input. Since the average luminance value Ca is a function of the center coordinates (x, y) and the radius r of the iris circle A, Ca (x,
y, r), and the average luminance value Cb is a function of the center coordinates (x, y) of the circle B and the radius r + α.
Also described as (x, y, r).

Next, a variable r representing the radius of the iris circle A is set to the minimum value MIN_r (P203). Next, the iris circle A
Y ₀ -MAX_Y is substituted for a variable y that means the y coordinate of the center of (P204). Next, x ₀ -MAX_X is substituted for a variable x representing the x coordinate of the center of the iris circle (P205).

Next, the average of the pixels on the circumference of the iris circle A and the circle B (the radius of the circle A is r and the radius of the circle B is r + α) shown in FIG. 7 centered on the coordinates (x, y). Brightness values Ca and Cb
Is obtained (P206). Here, α is a positive constant.

Next, it is determined whether the following equation (1) is satisfied (Cb-Ca> max_dC) (P207). When Expression 1 is satisfied, as shown in FIG. 8, the average luminance value P _i of the left and right partial areas I inside the iris circle A and the average luminance of the right and left partial areas O outside the iris circle A, as shown in FIG. _{Find the} value _Po (P
208). The region I, for example, as shown in FIG. 8, inner circle of the iris circle A AI (radius _{r × (1-d i)} )
(Where d _i is a positive constant) and a circle A outside the iris circle A
O (radius _{r × (1 + d o)} ) ( wherein, d _o is a positive constant)
And an area surrounded by a straight line having an angle 2θ at the center of the circle (where θ is a constant greater than 0 ° and smaller than 90 °).

Next, the average luminance value P _i and the average luminance value P
_o is less Equation 2 and 3 of _{MIN_P i <P i (x,} y, r) <MAX_P i Equation _{2 MIN_P o <P o (x} , y, r) < determine whether it satisfies both max_p _o Equation 3 (P209). Here, MIN_P _i is the minimum value of the luminance range of the iris, MAX_P _i
P _i is the maximum value of the luminance range of the iris, min_p _o is the minimum value of the luminance range of the sclera, max_p _o indicates a maximum value of the luminance range of the sclera.

If both equations 2 and 3 are satisfied, m
Substituting Cb-Ca for ax_dC, substituting x for PX,
Y is substituted for PY, and r is substituted for PR (P210).

Next, it is determined whether or not the following formula 4 x <x ₀ + MAX_X × 2 formula 4 is satisfied (P211). It should be noted that the process proceeds to the process P211 even if the determination is NO in the process P207 or P209. Here, when Expression 4 is satisfied, x + dx is substituted for x (where dx is a constant meaning a search step value of the x coordinate) (P21)
2), proceed to process P206. On the other hand, when Expression 4 is not satisfied, the process proceeds to Process P213.

When the process proceeds to the step 213, it is determined whether or not the following expression 5 y <y ₀ + MAX_Y × 2 expression 5 is satisfied (P213). Here, if Expression 5 is satisfied, y + dy is substituted for y (here, dy is a constant meaning a search step value of the y coordinate) (P214), and the process proceeds to P205. On the other hand, Equation 5
If is not satisfied, the process proceeds to processing P215.

When the process has proceeded to 215, it is determined whether or not the following formula 6, r <MAX_r, is satisfied (P215). Here, if Expression 6 is satisfied, r + dr is substituted for r (where dr is a constant meaning a search step value of r).
(P216) The process proceeds to Process P204. On the other hand, when Expression 6 is not satisfied, the process proceeds to Process P217.

When the process proceeds to step 217,
It is determined whether or not C is 0. If C is 0, a detection error signal is output (P219).
The center coordinates (PX, PY) and the iris diameter PR are output (P2
18), end the process (P220).

In the processing shown in FIG. 6, the case where the center position of the iris circle A is changed within a predetermined range centered on the coordinates (x ₀ , y ₀ ) has been described. Alternatively, the center position of the iris circle may be fixed at the coordinates (x ₀ , y ₀ ). In this case, the process P204 in FIG.
= Y ₀ , the process P205 becomes x = x ₀ , and the process P2
11, P212, P213, and P214 are omitted.

Further, in the processing of FIG.
And P209 are processes for improving the recognition accuracy of the iris circle, and can be omitted.

As described above, according to the first embodiment, the distance from the AF camera unit 1 to the iris can be measured by one AF camera unit 1. Further, since the AF camera unit 1 may be an existing camera with an AF function, the product cost of the camera device 10 can be reduced. Also, since the iris diameter R in the real space has very little individual difference, the accuracy of the measurement distance can be made relatively high by obtaining the camera distance based on the iris diameter r in the captured image.

Second Embodiment FIG. 9 is a block diagram showing a configuration of a camera device 11 with a distance measuring function according to a second embodiment of the present invention. FIG. 10 is a flowchart illustrating the operation of the camera device 11 with a distance measurement function according to the second embodiment.

The camera device 11 with a distance measuring function according to the second embodiment has a point that the user has a personal ID input section 8 for inputting personal identification information such as an ID number, and stores an iris diameter / camera distance correspondence table. The unit 9 has correspondence information between the iris diameter and the distance from the camera unit to the iris in real space for a plurality of registered humans, and the camera distance output unit 5 outputs the personal identification information input from the input unit 8. Only the point that the distance from the camera unit to the iris in the real space is measured based on the correspondence information selected according to the above is different from the camera device 10 with the distance measuring function according to the first embodiment. Note that the personal ID input unit 8 includes a card reader, buttons, or a touch panel. As described above, an example is shown in which an iris diameter / camera distance correspondence table is provided for each user, and identification information is input from the user before operation and used. By providing a correspondence table for each individual, a more accurate camera distance can be obtained.

Next, the operation of the camera device 11 with the distance measuring function will be described. As shown in FIG. 10, when the processing in the camera device 11 with the distance measuring function is started (P
301), a personal ID is input from the personal ID input section 8 (P302), and the proximity sensor 7 is activated (P3).
03). Next, when a person is detected by the proximity sensor 7 (P304), the AF camera unit 1 automatically adjusts the lens focus so as to focus on the face and shoots the face (P3).
05). The captured image is temporarily stored in the image storage unit 2 as face image information, and is processed by the eye position detection unit 3 (P306). Here, from the face image information stored in the image storage unit 2, the presence or absence of the face in the face image and the eye position are detected. If it is determined that no face exists or if the eye position cannot be detected, the process returns to the human detection processing by the proximity sensor 7 (P304).

Next, a process is performed by the iris diameter measuring unit 4 (P307). Here calculates the iris diameter r of the face image stored on the basis of the signal S ₃ about the eye position information obtained in the previous eye position detecting unit 3 in the image storage unit 2. If the iris diameter r cannot be measured because the iris cannot be found or the like, the detection process of the person by the proximity sensor 7 (P30)
Return to 4).

Next, the processing in the camera distance output section 6 is performed (P308). Here, the processing of extracting the value of the camera distance D from the iris diameter / camera distance correspondence notation unit 6 based on the iris diameter information S ₄ obtained by the processing in the iris diameter measuring unit 4 described above.

[0046] Finally, and outputs a signal S ₂ based on the face image information stored in the camera distance signal S ₅ and the image memory 2 corresponding to the distance from the AF camera unit 1 to the iris to the outside (P309), A series of processing ends (P310). still,
The above processing may be performed only on either the left or right iris, but may be performed on both the left and right irises, and the camera distance may be obtained using the average value of the left and right iris diameters.

In the second embodiment, a more accurate camera distance can be obtained because a camera distance correspondence table of iris diameter and camera distance is provided for each individual. In the second embodiment, if a user ID is not input, the same iris diameter / camera distance correspondence table as in the first embodiment may be used. Note that, other than the above, the second embodiment is the same as the first embodiment.

In the first and second embodiments, when the output of the face image signal is not required, only the camera distance signal is output from the camera device 10 or 11 having the distance measuring function to measure the distance. It may be used as a device. When the measured iris diameter information is required, a signal indicating the iris diameter may be output to be used as an iris diameter measuring device.

[0049]

As described above, according to the present invention,
The distance from the camera unit to the iris can be measured by one camera unit. Further, since the camera section may be an existing camera with an AF function, the product cost of the camera device can be reduced. In addition, since the iris diameter in the real space has very little individual difference, the accuracy of the measurement distance can be made relatively high by obtaining the camera distance based on the iris diameter in the captured image.

Further, when a camera distance correspondence table of iris diameter and camera distance is provided for each individual, the camera distance can be obtained. In the second embodiment, if the user ID is not input, a more accurate camera distance can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a camera device with a distance measurement function according to a first embodiment of the present invention.

FIG. 2 is a sketch of a situation where a human face is being photographed by the camera device of FIG. 1;

FIG. 3 is an enlarged view showing a pupil, an iris and a sclera of an eyeball of a human eye.

FIG. 4 is a diagram illustrating an example of a one-frame face image captured by the camera unit of FIG. 1 and stored in an image storage unit;

FIG. 5 is a flowchart illustrating an operation of the camera device with a distance measurement function according to the first embodiment.

FIG. 6 is a flowchart showing the operation of the iris diameter measuring unit of FIG. 1;

FIG. 7 is a diagram showing iris circles A and B used for measuring the iris diameter.

FIG. 8 is a diagram showing an inner region I and an outer region O of an iris circle A used for measuring the iris diameter.

FIG. 9 is a block diagram illustrating a configuration of a camera device with a distance measurement function according to a second embodiment of the present invention.

FIG. 10 is a flowchart illustrating an operation of the camera device with a distance measurement function according to the second embodiment.

[Explanation of symbols]

1 AF camera unit, 2 image storage unit, 3 eye position detection unit, 4 iris diameter measurement unit, 5 camera distance output unit,
6,9 Iris diameter / camera distance correspondence table storage unit, 7 Proximity switch, 8 Personal ID input unit, 10,11 Camera device with distance measurement function.

Continuing from the front page (72) Inventor Takahiro Watanabe 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. (72) Inventor Yasuhiro Cho 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industrial Co., Ltd. In-house (72) Inventor ▲ Taka ▼ Koji 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd. F-term (reference) 4C038 VA07 VB04 VC05 5B047 AA27 CB22 DC07

Claims (10)

[Claims] A camera for photographing a human face; an image storage for temporarily storing face image information based on an image signal output from the camera; and a face image based on the face image information. An eye position detection unit that detects the position of the eye in and outputs eye position information; an iris diameter measurement unit that measures the iris diameter of the eye based on the eye position information and the face image information; Has the correspondence information between the iris diameter measured by the method and the distance from the camera unit to the iris in the real space, and measures the distance from the camera unit to the iris in the real space based on the iris diameter and the correspondence information A camera device with a distance measuring function, comprising: 2. An input unit for inputting personal identification information, wherein the distance measuring unit is configured to store correspondence information between the iris diameter and the distance from the camera unit to the iris in real space for a plurality of registered humans. The distance measuring unit measures the distance from the camera unit to the iris in the real space based on the correspondence information selected according to the personal identification information input from the input unit. The camera device with a distance measurement function according to claim 1. 3. If the correspondence information to be selected in accordance with the personal identification information input from the input unit does not exist in the distance measurement unit, the distance measurement unit may be configured based on predetermined correspondence information stored in advance. 3. The camera device with a distance measuring function according to claim 2, wherein the distance from the camera unit to the iris in a real space is measured. 4. The measurement of the iris diameter in the iris diameter measuring section is performed by the eye position coordinates (x ₀ ,
The average luminance value Ca (r) of the pixels on the circumference of the first circle having a radius r centered on y ₀ ) and the second circle having a radius r + α (where α is a positive constant). The processing for obtaining the average luminance value Cb (r) of the pixels on the circumference is defined as MIN_r ≦ r ≦ MAX_
r (where MIN_r is r in the iris diameter measurement process)
MAX_r is the upper limit of r in the iris diameter measurement process. 2. The method according to claim 1, wherein the processing is performed for a plurality of values of the radius r that satisfies), and the value of r when Cb (r) −Ca (r) reaches the maximum value is output as the iris diameter. 4. The camera device with a distance measurement function according to any one of items 1 to 3. 5. The measurement of the iris diameter in the iris diameter measurement section is performed by using the eye position coordinates (x ₀ ,
The average luminance value Ca (r) of the pixels on the circumference of the first circle having a radius r centered on y ₀ ) and the second circle having a radius r + α (where α is a positive constant). The processing for obtaining the average luminance value Cb (r) of the pixels on the circumference is defined as MIN_r ≦ r ≦ MAX_
r (where MIN_r is r in the iris diameter measurement process)
MAX_r is the upper limit of r in the iris diameter measurement process. ), And MIN_P _i ≦ P _i ≦
Max_p _i (where, P _i is the average luminance value in a predetermined area inside the first circle, min_p _i is the lower limit of P _i that corresponds to the lower limit value of the luminance of the iris, max_p
_i is an upper limit value of P _i that corresponds to the upper limit value of the brightness of the iris. ) And _{MIN_P o ≦ P o ≦ MAX_P o} ( here, P _o
Is the average luminance value in a predetermined area outside of the first circle, min_p _o is the lower limit of P _o, max_p _o
Is the upper limit of _Po . ) Radius r of multiple values that satisfy
The method according to any one of claims 1 to 3, wherein the calculation is performed by outputting the value of r when Cb (r) -Ca (r) reaches a maximum value as an iris diameter. A camera device with a distance measurement function as described. 6. An eye position coordinate output by the eye position detection unit is (x ₀ , y ₀ ), and x is x ₀ −MAX_X ≦ x ≦ x
₀ + MAX_X (where MAX_X is a positive constant), and y is y ₀ −MAX_Y
When a plurality of values satisfying ≦ y ≦ y ₀ + MAX_Y (where MAX_Y is a positive constant), the measurement of the iris diameter in the iris diameter measurement unit is performed using coordinates (x,
y) mean luminance value Ca (x, y, r) of pixels on the circumference of the first circle of radius r centered on y) and the second circle of radius r + α (where α is a positive constant ) Is a process of obtaining the average luminance value Cb (x, y, r) of the pixels on the circumference of MIN_
r ≦ r ≦ MAX_r (where MIN_r is a lower limit value of r in the iris diameter measurement process, and MAX_r is an upper limit value of r in the iris diameter measurement process). And Cb (x, y, r) -Ca
The distance measurement function according to any one of claims 1 to 3, wherein the value is obtained by outputting the value of r when (x, y, r) reaches a maximum value as an iris diameter. Camera device. 7. An eye position coordinate output by the eye position detection unit is (x ₀ , y ₀ ), and x is x ₀ −MAX_X ≦ x ≦ x
₀ + MAX_X (where MAX_X is a positive constant), and y is y ₀ −MAX_Y
When a plurality of values satisfying ≦ y ≦ y ₀ + MAX_Y (where MAX_Y is a positive constant), the measurement of the iris diameter in the iris diameter measurement unit is performed using coordinates (x,
y) mean luminance value Ca (x, y, r) of pixels on the circumference of the first circle of radius r centered on y) and the second circle of radius r + α (where α is a positive constant ) Is a process of obtaining the average luminance value Cb (x, y, r) of the pixels on the circumference of MIN_
r ≦ r ≦ MAX_r (where MIN_r is the lower limit of r in the iris diameter measurement process and MAX_r is the upper limit of r in the iris diameter measurement process), and MI
In _{N_P i ≦ P i ≦ MAX_P i} ( where, P _i is the average luminance value in a predetermined area inside the first circle, MIN_
P _i is the lower limit of P _i that corresponds to the lower limit value of the luminance of the iris, max_p _i is P _i that corresponds to the upper limit value of the luminance of the iris
Is the upper limit. ) And MIN_P _o ≦ P _o ≦ MAX_P _o
(Wherein, P _o is the average luminance value in a predetermined area outside of the first circle, min_p _o is the lower limit of P _o, max_p _o is an upper limit value of P _o.) Is executed for a plurality of values of the radius r satisfying Cb (x, y, r) −
The distance measurement function according to any one of claims 1 to 3, characterized in that the distance measurement function is performed by outputting a value of r when Ca (x, y, r) reaches a maximum value as an iris diameter. With camera device. 8. The camera device with a distance measuring function according to claim 1, wherein the camera unit is an auto-focus type CCD camera. 9. The correspondence table based on the result of previously measuring the correspondence between the diameter of the iris measured by the iris diameter measurement unit and the distance from the camera unit to the iris in real space. The camera with a distance measurement function according to any one of claims 1 to 8, further comprising a storage unit that measures the distance from the camera unit to the iris in the real space using the correspondence table. apparatus. 10. An arithmetic operation according to a relational expression based on a result of previously measuring the correspondence between the diameter of the iris measured by the iris diameter measuring unit and the distance from the camera unit to the iris in real space by the distance measuring unit. The camera device with a distance measuring function according to any one of claims 1 to 8, wherein the camera device has a unit and measures a distance from the camera unit to the iris in a real space using the relational expression.