DESCRIPTION
Title of the Invention
OBJECT DETECTION DEVICE, OBJECT DETECTION METHOD, AND OBJECT
DETECTION SYSTEM
Technical Field '.'
This invention relates to an object detection device, an object detection method, and an
object detection system.
Background Art
In recent years, so-called "bird strike" has become a problem, in which a moving object,
' I e.g., a bird, intrudes into a' region where an airport, a wind power generation facility, or the like
is constructed, and collides with an aircraft taking off from or landing at the airport, or with a
windmill of the wind power generation facility.
Accordingly, there has been desired a detection device for detecting the intrusion of a
bird into such region.
As a device for detecting a bird, there is known a device for imaging a flying object at
minute time intervals, analyzing a flight pattern of the flying object from a brightness pattern
distribution, making a database of the flight patterns, and detecting whether or not the flying
object is a bird (Patent Document l ).
Moreover, there is also known a device for calculating 3D coordinates of a flying object
based on a distance between the flying object and a camera and azimuth data, and detecting a
bird from a flight trajectory (Patent Document 2).
Further, there is known a device for imaging a flying object and a fixed object in the
same image, thereby acquiring the height of the flying object (Patent Document 3).
Still further, there is known a device for determining whether or not a flying object is a
bird based on the speed of the flying object (Patent Document 4).
Prior Art Documents
Patent Document
2
Patent Document 1: WO-A-2009/102001
Patent Document 2: JP-A-2011-95112
Patent Document 3: .TP-A-2010-223752
Patent Document 4: JP-A-2010-193768
Summary of the Invention
Problem to be Solved by the In'v''e ntion
On this occasion, in terms of reducing damage to aircrafts and windmills caused by a
bird strike, maintaining peripheries of the above-mentioned region so as to make the region an
environment repelling birds, thereby reducing the frequency of appearance of birds themselves,
results in a significant achievement and is thus important On the other hand, the environment
repelling birds depends greatly on the type of the bird, and it is thus very important to
discriminate the type of the bird in the peripheries of the regions.
However, although the devices disclosed in Patent Documents 1 to 4 can determine
whether or not the flying object is a bird, it is hard for those devices to accurately discriminate
the type of the bird.
This invention has been made in view of the above-mentioned problem, and therefore
has an object to provide an object detection device capable of accurately discriminating the type
of a moving object
Means to Solve the Problem
In order to solve the problem mentioned above, as a first aspect of the present invention,
there is provided an object detection device, comprising: a primary determination unit for
determining, from an image acquired by imaging a moving object, whether or not the moving
object is a specific detection subject; and an object detection determination unit for estimating,
based on a contour of the moving object determined to be the specific detection subject by the
primary determination unit and contour shape information, which is a contour prepared for each
of types of the specific detection subject, a type of the moving object out of the types of the
specific detection subject.
As a second aspect of the present invention, there is provided a program for causing a
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computer to operate as an object detection device, the object detection device comprising: a
primary determination unit for determining, from an image acquired by imaging a moving object,
whether or not the moving object is a specific detection subject; and an object detection
determination unit for estimating, based on a contour of the moving object determined to be the
specific detection subject by the primary determination unit and contour shape inform~tion,
which is a contour prepared for each of types of the specific detection subject, a type of the
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moving object out of the types of the specific detection subject.
As third aspect of the present invention, an object detection method, comprising: (a)
imaging a moving object to acquire an image; (b) primarily determining, from the image,
whether or not the moving object is a specific detection subject; and (c) estimating, based on a
contour of the moving object determined to be the specific detection subject by the primary
determination and contour shape information, which is a contour prepared for each of types of
the specific detection subject, a type of the moving object out of the types of the specific
detection subject.
As fourth aspect of the present invention, there is provided an object detection system,
comprising: an image pickup device for imaging a moving object to acquire an image; a primary
determination unit for determining, from the image, whether or not the moving object is a
specific detection subject; and an object detection determination unit for estimating, based on a
contour of the moving object determined to be the specific detection subject by the primary
determination unit and contour shape information, which is a contour prepared for each of types
of the specific detection subject, a type of the moving object out of the types of the specific
detection subject.
Effect of the Invention
According to this invention, the object detection device capable of accurately
discriminating the type of the moving object can be provided.
Brief Description of the Drawings
Fig. 1 is a block diagram for illustrating an outline of an object detection system 1
according to an embodiment of this invention.
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rig. 2 is a block diagram for illustrating an object detection device 5 of Fig. 1.
rig. 3 is a block diagram for illustrating details ofthc object detection system 1.
Fig. 4 is a flowchart for illustrating a method of detecting a bird, and estimating a bird
type/a flying attitude using the object detection system 1.
Fig. 5 is a flowchart for illustrating in detail Steps Sll and S12 of Fig. 4.
Fig. 6 is a diagram for illustrating a method of reducing the dimensions of outer shape
information on the bird from two dimensions to one dimension.
Fig. 7 is a diagram for illustrating the method of reducing the dimensions of the outer
shape information on the bird from two dimensions to one dimension.
Mode for Embodying the Invention
Now, a preferred embodiment of this invention is described in detail with reference to
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the drawings.
First, a configuration of an object detection system 1 including an object detection
device 5 according to this embodiment is described with reference to Fig. 1 and Fig. 2.
In the following, a bird strike prevention device for estimating a type of bird from an
image is described as an example of the object detection system 1 (object detection device 5).
As illustrated in Fig. 1 and Fig. 2, the object detection system 1 includes an image
pickup device 3 for imaging a moving object to acquire an image. The object detection system
1 also includes an object detection device 5 including an object detection determination unit 7.
The object detection determination unit 7 includes a bird candidate determination unit 17 serving
as a primary determination unit for determining whether or not a moving object is a specific
detection subject (a bird in this case) from the image acquired by imaging the moving object and
a bird type/attitude estimation unit 19 for estimating, based on a contour of the moving object
determined as a bird by the bird candidate determination unit 1 7, and a wire frame model library
(hereinafter referred to as WFM library 9) storing contour shape information, which is a contour
prepared for each of types of the specific detection subject (types of the bird in this case), the
type of the moving object (the type of the bird in this case) out of the types of the specific
detection subject.
In this case, the image pickup device 3 is a single monitoring camera. The surveillance
camera is installed on a fixed base and is configured to take an image by carrying out fixed point
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monitoring at a constant azimuth or by canying out turn monitoring all around or in a certain
range through turning. Further, the image pickup device 3 transmits the taken image to the
object detection device 5 in a wired or wireless manner.
According to this embodiment, the object detection device 5 is used in the bird strike
prevention device, and hence the image pickup device 3 is installed at an end of a runway of an
airport or in a facility of a wind power plant.
Moreover, according .to. 't his embodiment, the bird is detected as the specific detection
subject, but types of birds and dogs and types of airplanes and helicopters are also exemplified as
the specific detection subject.
Further, according to this embodiment, the bird type is estimated as the type out of the
types of the specific detection subject. As used herein, the type out of the types of the specific
detection subject refers to a type such as crow or pigeon when the specific detection subject is
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the bird.
The object detection device 5 is configured to extract an outer shape (contour in this
case) of the moving object from the image taken by the image pickup device 3, and estimate the
type of the bird from the extracted contour. Further, as described later, according to this
embodiment, the object detection device 5 additionally has a function of estimating an attitude of
the bird, a frmction of estimating a flight path from the type and the attitude of the bird, a
function of finally determining whether or not the moving object is a bird from the flight path,
and the type and the attitude of the bird, and a function of generating an alarm when likelihood
of a bird strike exists.
An electronic computer, e.g., a personal computer, is used as the object detection device
5, but the object detection device 5 is not particularly limited to a specific device as long as the
object detection device 5 is a device having a function of performing processing to be described
later.
Referring to Fig. 3, a detailed description is now given of a configuration of the object
detection system I, in particular, a configuration of the object detection device 5.
As illustrated in Fig. 3, the object detection device 5 includes an image data input
processing unit 13 for inputting data of the image taken by the image pickup device 3, a bird
candidate image extraction unit 15 for extracting a contour line of a moving object from the
image to generate moving object information 6, the object detection detennination unit 7 for
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estimating absence/presence, type, and attitude of the bird based on the moving object
information 6 extracted by the bird candidate image extraction unit 15, an alarm notification unit
25 for generating an alarm when the bird is likely to intrude into a prioritized monitoring region
based on the detection result of the object detection determination unit 7, and a storage unit 2 for
storing an operation program 22 for operating the object detection device 5, and various types of
information and libraries described later .
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The object detection determination unit 7 includes the bird candidate determination unit
17 for carrying out, from the moving object information 6, a primary determination regarding
whether or not the moving object is a bird, the bird type/attitude estimation unit 19 for estimating
the type and the attitude of the bird from the moving object information 6, a flight path
estimation unit 21 for estimating a flight path of each of bird candidates (moving objects), and a
bird detection final determihation unit 23 for finally determining whether or not each of the bird
candidates (moving objects) is to be recognized as a bird.
In more detail, the image data input processing unit 13 is configured to receive the taken
image transmitted from the image pickup device 3, and always record image data corresponding
to three frames in a first-in first-out manner in an internal temporary recording memory. Image
disturbance caused by a rolling shutter phenomenon and an operation error of a camera platform
of the image temporarily stored in the image data input processing unit 13 is corrected, and the
image is then sequentially output to the bird candidate image extraction unit 15.
The bird candidate image extraction unit 15 is configured to extract the contour line of
the moving object from differential information on the image of three successive frames.
Moreover, information, which is a combination of an imaging time and a relative azimuth of the
moving object with respect to the camera, brightness information at coordinates of the entire
object on the image, and a histogram-of-oriented-gradients (HOG) characteristic amount, is
stored as moving object information 6 in the storage unit 2.
The bird candidate determination unit 17 is configured to refer to a bird discrimination
library 24 of the storage unit 2 based on the HOG characteristic amount of the moving object
infmmation 6, thereby making a determination (primary determination) regarding whether or not
the moving object is a bird with a binary discriminator that is based on the principle of suppmi
vector machine (SVM), a neural network, or the like.
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The bird discrimination library 24 is a database for generating a discrimination criterion
for the binary discriminator. When the SVM is employed, the bird discrimination library 24 is
constructed by image information on the bird and image information on objects other than the
bird as comparison subjects.
The bird type/attitude estimation unit 19 is configured to successively compare the
contour information on the bird selected from the WFM library 9 provided in the storage unit 2
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and the moving object information 6 with each other, thereby extracting the type and the attitude
of the bird highest in similarity (secondary determination). Moreover, the bird type/attitude
estimation unit 19 is configured to store in the storage unit 2 information acquired by adding the
estimated bird type, attitude, and a distance or position information on a map from the image
pickup device for the bird to the moving object information 6 as bird candidate information 10.
The WFM library 9 holds information on a standard body shape and a wing flap
simulated as a wireframe model for each of bird types observed in a periphery of a prioritized
monitoring region. Moreover, the WFM library 9 holds plane projection contour shape
information in cases where rotational angles about three axes and a wing flap angle are each
changed at certain ratios for each of the birds.
According to this embodiment, the wireframe model is used to generate the plane
projection contour shape information in this way. This is for the following reasons.
( 1) At least thousands of examples of image information are necessary for generating the plane
projection contour shape information from images of birds prepared in advance.
(2) When the information (i.e., reference model) simulating the standard body shape and wing
flap is generated as the wire frame model, the model for each of the bird types can be relatively
easily generated from a result of measuring skeletal specimens and images of characteristic
attitudes and partial shapes of the corresponding bird type. In addition, a contour after a change
in the attitude about the three axes can be generated in a short period compared with a case
where the plane projection contour shape information is generated from images of birds prepared
in advance.
The flight path estimation unit 21 is configured to estimate a flight path of an individual
bird from the bird candidate information I 0, and successively store the flight path as flight path
tracking information 18 in the storage unit 2.
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The bird detection final determination unit 23 is configured to compare the flight path
tracking information 18 and characteristic information of each of the birds recorded in a bird
type characteristic library 14 in the storage unit 2 with each other, thereby finally determining
whether or not each of the bird candidates is to be recognized as the bird.
The bird type characteristic library 14 is a library for recording an appearance prior
probability for each of the bird types observed in the periphery of the facility when standard
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body length, mass, flight speed, wing flap frequency, and month and time zones are considered
as criteria.
The alarm notification unit 25 is configured to evaluate danger of the intrusion of the
bird into the region of the facility specified by prioritized monitoring region information 16
stored in the storage unit 2 for each of the bird candidates (moving objects) based on the flight
path tracking information 1~. and generate an alarm when danger higher than a certain level
exists, that is, when a bird strike is likely to occur.
The prioritized monitoring region information 16 is information defining regions where
an intrusion of the bird needs to be monitored in a facility, and information on regions where, for
example, an airport or a wind power generation facility exists.
In Fig. 3, the moving object information 6, the bird discrimination library 24, the WFM
library 9, the bird candidate information 10, the flight path tracking information 18, the bird type
characteristic library 14, the prioritized monitoring region information 16, and the operation
program 22 are stored in the storage unit 2 provided in the object detection device 5, but may be
replaced by an external storage device or external information connected via a network, e.g., the
World Wide Web (WWW).
Next, an operation of the object detection system 1, which is an operation for preventing
a bird strike in this case, is described with reference to Fig. 4 to Fig. 6.
First, the operation program 22 of the object detection device 5 is started.
Then, the image pickup device 3 carries out fixed point monitoring at a constant
azimuth, or turn monitoring all around or in a certain range through turning, thereby taking
images in the prioritized monitoring region defined by the prioritized monitoring region
information 16 or the periphery thereof. The monitoring device 3 continuously transmits the
taken image, for example, at 60 frames per second to the image data input processing unit 13 of
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the object detection device 5, and the image data input processing unit 13 receives the image (S1
of Fig. 4). When the prioritized monitoring region is an airport, the image pickup device 3
acquires an image in each of directions including a direction of a runway, thereby taking images
of the airport and a periphery of the airport.
The image data input processing unit 13 corrects the disturbance of the image caused by
the rolling shutter phenomenon and the operation error of the camera platform of the received
''' image, and then sequentially outputs the corrected image to the bird candidate image extraction
unit 15.
The bird candidate image extraction unit 15 binarizes, in terms of the brightness, three
images (respectively referred to as frames n-1, n, and n+l) extracted successively or at a constant
interval in a time series from the received images, and then respectively generates differential
images m=n-(n-1) and m+·Y=(il+ 1 )-n. Further, a moving object, which is a bird candidate, is
extracted from the three original images by generating an AND image D=m*(m+ 1) of m and
m+ 1. A position of the center of gravity, a shape, and a size on D of the moving object
extracted on D are normalized with respect to reference values set in advance, and the HOG
characteristic amount is calculated. Then, the "moving object information 6" is generated by
adding the imaging time and the optical axis azimuth of the image pickup device at the imaging
time to the HOG characteristic amount, and the moving object information 6 is stored in the
storage unit 2 (S2 of Fig. 4).
The bird candidate determination unit 17 applies binary discrimination to each piece of
the moving object information 6 by using a threshold generated from the database of the bird
discrimination library 24 as a reference based on the HOG characteristic amount of the moving
object information 6, thereby carrying out the primary determination regarding whether or not
the bird candidate (moving object) is a bird (S3 of Fig. 4).
When the moving object is determined as an object other than the bird through the
primary determination, the moving object information 6 on this moving object is deleted, and the
operation returns to Step S 1 (S4 of Fig. 4 ).
For a moving object determined as a bird by the primary determination, the bird
candidate image extraction unit 15 carries out normalization of increasing or decreasing the
shape information of the moving object information 6 to a size set in advance, e.g., 1 OOx 100 px,
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thereby extracting the contour information (SS of Fig. 4).
Then, the bird type/attitude estimation unit 19 selects one sample image out of contour
images of the birds projected on the two-dimensional plane through the wire frame model in the
WFM library 9 stored in the storage unit2 (S6 of Fig. 4).
The sample image is an image acquired by changing respective angles by approximately
10° to 20° as parameters, which are the bird type, the three-axis attitude and the wing flap angle .
. '' Sample data is prepared for ten types of birds while the three axes and the wing flap angle are
changed by the increment of 10°.
Then, the bird type/attitude estimation unit 19 calculates a cross-correlation from the
selected sample image and the normalized bird candidate image contour, and determines whether
or not the result is more than a threshold set for each of the bird types (S7 of Fig. 4).
When the result is 'mdre than the threshold, the comparison is finished in this state, and
the bird type, the attitude, and the wing flap angle of the bird candidate (moving object) are
estimated to be values of the sample image. In other words, the moving object is estimated to
be the corresponding bird type. When the result is less than the threshold, a new sample is
selected, and the same comparison is repeated. On this occasion, the bird type/attitude
estimation unit 19 determines whether or not a predetermined maximum number oftria1s is
reached (S8 of Fig. 4). When a correlation equal to or more than the threshold is not found
after the maximum number of trials, the comparison is finished, and the moving object is
estimated to be the sample presenting the maximum correlation out of all the trials.
In this way, the object detection system 1. is configured to analyze the contour of a bird
to estimate the type of the bird, and can thus more accurately estimate the type of the bird
compared with related-art analysis of using parameters, e.g., a flight pattern, a flight trajectory, a
flight height, and a flight speed, which are hard to use to directly estimate the bird type.
In other words, the object detection system 1 is configured to be able to define the
discrimination of the bird type based on the single scale, which is the conformity with the
two-dimensional contour shape sample having the bird type, the attitude, and the wing flap angle
as the parameters, thereby uniformly defining the likelihood relating to the discrimination of the
bird type, and be able to discriminate the type more accurately than a related-art device.
Incidentally, the above-mentioned processing is a search problem in five dimensions,
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which is the bird type, the three-axis attitude, and the wing flap angle, and a difference between
the samples in the WFM library 9 presents a so-called "sandstorm" distribution in the selection
of the sample image, and is therefore differentiable nowhere, and a next candidate cmmot be
predicted through the Newton-Raphson method or the like. Therefore, an exhaustive search is
generally necessary to acquire the optimal solution. However, as described above, the number
of samples to be compared reaches approximately 8 million, and execution of the exhaustive
search takes a very long time. · ''
Thus, according to this embodiment, the bird type/attitude estimation unit 19 employs
general characteristics relating to the image pickup device 3 and ecology of the bird as prior
information, and compares the sample, in descending order of the probability of the correlation
with the bird candidate image, with the bird candidate image, thereby attempting to find the
optimal sample after a relatively small number of iterations of the calculation.
According to this embodiment, the following four items are employed as the prior
information.
Prior information (1 ): The bird does not often fly at a large angle (more than approximately
±20°) in the pitch direction.
Prior information (2): The body shape of the bird is left-right symmetrical, and the number of
factors for changing the outer shape other than the wing flap is small.
Prior information (3 ): The types of the bird to be detected are limited depending on the season
and the time.
Prior information (4): The angle of the field of the image pickup device 3 is usually
approximately ±20° at the maximum.
When the above-mentioned four items of the prior information are employed, the
following items can be assumed at a relatively high probability for the attitude of the bird
candidate (moving object).
(i) The bird apparently flies with an attitude close to a pitch angle of 0° and a roll angle of 0°.
(ii) When a median in the vertical direction is close to a center of gravity value, the wing flap
angle is around 90°.
(iii) The bird types to he examined can be prioritized depending on the season and the time.
Based on the assumptions (i) to (iii), a sample search is carried out in the following
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sequence.
S l 01: The bird type/attitude estimation unit 19 sets initial values of the five types of
parameters as (bird type=type having highest appearance prior probability for the season/time,
each of the 3 axes=Oo, and the wing flap angle=90°), and compares the initial values with the
contour of the bird candidate (moving object).
Sl02: The bird type/attitude estimation unit 19 sequentially changes one ofthe
respective parameters at a time. 't'o select a sample. In this configuration example, a sample
changed in the wing flap angle by 20° from the sample in Step S 101 is used as a second sample
for the comparison with the bird candidate (moving object). After all the variations in the wing
flap angle are confirmed, samples where the angle is sequentially changed in the yaw axis, the
roll axis, and the pitch axis are used. Subsequently, Steps Sl02 and Sl03 are sequentially
repeated in descending order of the appearance frequency of the bird type.
Incidentally, the comparison in the cross-correlation handles two-dimensional shapes of
the bird candidate image and the sample image as illustrated in Fig. 6, and thus results in a
relatively large calculation amount. Thus, the simplification and the increase in the speed of
this calculation are very important for realizing real time performance of the device and a
reduction in the cost of the device.
A cross-correlation C of the binarized image of Fig. 6 can be represented as Equation
( 1) as an example where a function representing the two-dimensional shape of the bird candidate
or the sample image is denoted by cp and the average of cp is denoted by ~.
C"'(S(¢1-(1) · (¢2-(2)dA)/(J(¢1-(1)2dA · J(¢2-(2)2dA)1/2 "·(1)
On the other hand, according to this embodiment, the function cp representing the two
dimensional shape and ~ are converted to vectors <1> and 3 having a distance s from a reference
point on the contour line as a parameter, and the cross-correlation between the bird candidate
(moving object) and the sample is changed to C so as to be treated as a cross-correlation V of
vectors represented as Equation (3) as an example, thereby, as illustrated in Fig. 7, decreasing the
number of dimensions of the outer shape information on the bird from two to one to decrease a
calculation amount.
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cD={x(s), y(s}}, :=:"' { c {x(s)}, c {y(s)}} ···(2)
The bird type/attitude estimation unit 19 adds the bird type, the three-axis attitude, and
the wing flap angle to the movi1,1g object information 6 for the bird candidate (moving object) for
which those pieces of information are estimated through evaluation by using the
cross-correlation V, thereby generating "bird candidate information I 0", and stores the bird
candidate information I 0 in the storage unit 2 (S9 of Fig. 4).
Then, the flight path estimation unit 21 estimates the flight path of the bird candidate
(moving object) through the following procedure, and newly generates or updates the flight path
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tracking information 18 (S10 ofFig. 4).
First, the flight path estimation unit 21 estimates the actual body length of the bird from
the bird type estimated by the bird type/attitude estimation unit 19. Then, the body length on
the image of the bird candidate is calculated based on the attitude estimation value, and the
distance from the image pickup device 3 to the bird is also calculated through a simple
proportion based on the body length estimation value, the size on the image, and the focal length
of the image pickup device 3. The installation position of the image pickup device 3 and the
orientation azimuth upon the imaging are known, and thus the position of the bird on the map is
calculated based on the installation position and the orientation azimuth.
Then, the flight path estimation unit 21 compares the calculated type and position on the
map of the bird candidate (moving object) with the flight path tracking information 18 before the
current time point, thereby associating the bird candidate information 10 with the flight path
tracking information 18. When information which can be associated with the flight path
tracking information 18 does not exist, information is newly added.
Then, as the final determination, the bird detection final determination unit 23 compares
the flight path tracking information 18 with the ecology characteristic unique to the bird type
recorded in the bird type characteristic library 14 (S11 of Fig. 4), and excludes a bird candidate
(moving object) that apparently poses a problem as a bird (Sl2 of Fig. 4).
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Specifically, the bird detection final determination unit 23 confirms consistency between
the attitude and a flight direction of the moving object (S21 of Fig. 5).
In other words, the bird detection final determination unit 23 confirms whether or not
the moving object primarily determined as a bird is flying toward a direction which is usually an
improbable direction, e.g., a rear direction or a back direction.
Then, the bird detection final determination unit 23 confirms whether or not the moving
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object primarily determined as a bird presents a motion deviating from ranges ofthe flight speed
and the wing flap frequency unique to the bird type (S22 of Fig. 5).
The bird detection final determination unit 23 finally determines, based on those
confirmations and from information acquired by observing the attitude and the wing flap of each
of the birds in a time series, whether or not the moving object is a bird (S23 of Fig. 5).
When the moving obj;ect is determined to be a bird as a result of the final determination,
the flight path tracking information 18 on this moving object is added or updated (S24 of Fig. 5).
When the moving object is determined not to be a bird, the flight path tracking information 18 on
this moving object is deleted (S25 of Fig. 5 and S12 of Fig. 4).
In this way, in the object detection system 1, the bird detection final determination unit
23 is configured to discriminate whether or not a moving object is a bird based on not only the
shape information but also the characteristics of each bird type, e.g., the flight attitude, the flight
speed, and the wing flap frequency.
Therefore, whether or not a moving object is a bird can be discriminated more
accurately.
Finally, the alarm notification unit 25 compares the flight path tracking information 18
and the prioritized monitoring region information 16 with each other, thereby determining
whether or not the bird is likely to intrude into the prioritized monitoring region. When the bird
is determined to likely.to intrude into the region, the alarm notification unit 25 issues the alarm
to a system or a person in charge of surveillance that monitors the prioritized monitoring region
(S13 of Fig. 4).
What is specifically issued as the alarm is not particularly limited as long as the alarm
allows the system or person in charge of surveillance to be warned to recognize the alarm, and
examples thereof include transmission of alarm information to the system or the person in charge
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of surveillance and emission of a physical sound, light, or the like. Moreover, the flight
trajectory of a bird may always be displayed on a display or the like in place of the alarm.
A description has been given of the operation of the object detection system 1.
According to this embodiment, the object detection system 1 includes the image pickup
device 3 for imaging a moving object to acquire an image, and the object detection device 5
including the object detection determination unit 7. The object detection determination unit 7
includes the bird candidate determination unit 17 for determining, from the image acquired by
imaging the moving object, whether or not the moving object is a bird, and the bird type/attitude
estimation unit 19 for estimating the bird type of the moving object based on the contour of the
moving object determined as a bird by the bird candidate determination unit 17 and the WFM
library 9 storing contour shape information, which is the contour prepared for each of the types
of the bird.
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Therefore, the object detection system 1 can accurately discriminate the type of the
moving object.
Industrial Applicability
In the above, this invention is described by way of the embodiment and Example, but
the embodiment and Example are merely ones used to describe the invention by giving an
example, and are not intended to limit the scope of this invention thereto. It should be
understood that a person skilled in the art could arrive at various modification examples and
improvement examples based on the above description, and that those modification examples
and improvement examples are included in the scope of this invention.
For example, in the embodiment described above, the case is described where this
invention is applied to the bird strike prevention device at an airport or a wind power generation
facility (windmill), but this invention is by no means limited to this case. This invention is
applicable to any device required to surveil flying and arrival of birds, e.g., a device for
preventing feeding damage at a farm caused by birds or animals.
Moreover, according to the embodiment, the bird type is estimated from the outer shape
of the moving object, but the application subject of this embodiment is not limited to the
estimation of the bird type, and the detection subject can be any animal other than the bird, e.g., a
human or a mammal, or an arbitrary object set by the user as long as the type of the moving
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object can be identified from the outer shape.
Further, according to the embodiment, the object detection system 1 includes one image
pickup device 3 and one object detection device 5, but the number of the image pickup devices 3
and the number of the object detection devices 5 are not limited to one, and a plurality of each of
those devices may be simultaneously connected. In this case, the pieces of output image
information of the respective image pickup devices 3 are output in parallel to all the object
detection devices 5, and the ob. j'e' ct detection device 5 can select one of the image pickup devices
3 whose input is to be processed through an operation of the user.
Each of the units of the object detection device 5 may be implemented with the use of a
combination of hardware and software. In a mode where hardware and software are used in
combination, a program for causing a computer to operate as the object detection device 5 is
deployed onto a RAM, and a hardware component, e.g., a control unit (CPU), is operated based
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on the program, to thereby cause respective units to operate as various types of components.
Further, the program may be recorded onto a recording medium to be distributed. The program
recorded onto the recording medium is read into a memory in a wireless or wired manner or via
the recording medium itself to cause the control unit or the like to operate. Examples of the
recording medium include an optical disc, a magnetic disk, a semiconductor memory device, and
a hard disk.
Reference Signs List
1 object detection system
2 storage unit
3 image pickup device
5 object detection device
6 moving object information
7 object detection determination unit
9 WFM library
10 bird candidate information
13 image data input processing unit
14 bird type characteristic library
15 bird candidate image extraction unit
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1 6 prioritized monitoring region information
17 bird candidate determination tmit
18 flight path tracking information
19 bird type/attitude estimation unit
21 flight path estimation unit
22 operation program
23 bird detection final de't'e'r mination unit
24 bird discrimination library
25 alarm notification unit
This application claims the priority based on Japanese Patent Application No.
2014-095815, filed on May 7,;2014, the entire disclosure of which is incorporated herein by
reference.

CLAIMS
1. An object detection device, comprising:
a primary determination unit for determining, from an image acquired by imaging a
moving object, whether or not the moving object is a specific detection subject; and
an object detection determination unit for estimating, based on a contour of the moving
object determined to be the specific detection subject by the primary determination unit and
contour shape information, whic'h'' i s a contour prepared for each of types of the specific detection
subject, a type of the moving object out of the types of the specific detection subject.
2. An object detection device according to claim 1, wherein:
the specific detection subject comprises a bird;
the object detection device further comprises a bird image candidate extraction unit for
extracting a contour of the bird from the image; and
the object detection determination unit comprises a bird detection determination unit for
estimating a type of the bird from the contour.
3. An object detection device according to claim 2, wherein:
the bird image candidate extraction unit is configured to store information including a
contour line of the bird extracted from the image as moving object information; and
the bird detection determination unit comprises:
a wireframe model library storing information on a wireframe of simulating a
standard body shape and a wing flap for each of the types of the bird and plane projection
contour shape information when rotational angles about three axes and a wing flap angle are
each changed at certain rates for each of the types of the bird; and
a bird type/attitude estimation unit for comparing the moving object
information with the wire frame model library to estimate the type and an attitude of the bird.
4. An object detection device according to claim 3, wherein:
the moving object information and the plane projection contour shape information
include a vector having a distance from a reference point to the contour as a parameter; and
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the bird detection determination nnit is configured to estimate the moving object as a
corresponding bird type when a cross-conclation of the vector is more than a threshold set for
each of the bird types.
5. An object detection device according to claim 3 or 4, wherein the bird type/attitude
estimation unit is configured to employ, when the moving object information and the wireframe
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model library are compared with each other, general features relating to an image pickup device
for imaging the moving object and the moving object as prior information, and to compare,
based on the prior information, the plane projection contour shape information with the moving
object information in descending order of a probability of correlation with the contour of the
moving object, to thereby estimate the type of the bird .
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6. An object detection device according to any one of claims 3 to 5, further
comprising a flight path estimation nnit for estimating a flight path of the bird from the type and
the attitude of the bird estimated by the bird type/attitude estimation unit.
7. An object detection device according to claim 6, further comprising a bird detection
final determination unit for confirming, from the type and the attitude of the bird estimated by
the bird type/attitude estimation unit and the flight path estimated by the flight path estimation
unit, consistency of the attitude and a flight direction of the moving object, and consistency of a
flight speed and a wing flap frequency nnique to the bird type, to thereby finally determine
whether or not the moving object is a bird.
8. An object detection device according to claim 6 or 7, further comprising an alarm
notification unit for determining, from the flight path, whether or not likelihood that the bird
intrudes into a region set in advance exists, and generating an alarm when the likelihood exists.
9. A program for causing a computer to operate as an object detection device, the
object detection device comprising:
a primary determination unit for determining, from an image acquired by imaging a
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moving object, whether or not the moving object is a specific detection subject; and
an object detection determination unit for estimating, based on a contour of the moving
object dete1mined to be the specific detection subject by the primary determination unit and
contour shape information, which is a contour prepared for each of types of the specific detection
subject, a type of the moving object out of the types of the specific detection subject.
10. An object detection method, comprising:
(a) imaging a moving object to acquire an image;
(b) primarily determining, fi·om the image, whether or not the moving object is a
. specific detection subject; and
(c) estimating, based on a contour of the moving object determined to be the specific
detection subject by the primary determination and contour shape information, which is a
contour prepared for each of types of the specific detection subject, a type of the moving object
out of the types of the specific detection subject.
11. An object detection system, comprising:
an image pickup device for imaging a moving object to acqnire an image;
a primary determination unit for determining, from th(\ image, whether or not the
moving object is a specific detection subject; and
an object detection determination unit for estimating, based on a contour of the moving
object determined to be the specific detection subject by the primary determination unit and
contour shape information, which is a contour prepared for each of types of the specific detection
subject, a type of the moving object out of the types of the specific detection subject.
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12. An object detection system according to claim 11, wherein the image pickup
device comprises a single monitoring camera.