Photographing system, photographing device, and photographing method

Abstract

To provide a photographing system, a photographing device, and a photographing method that can focus on a photographing object efficiently with high accuracy.SOLUTION: The present disclosure is a photographing system for photographing a target area. The photographing system includes: a photographing unit that photographs the target area; a distance detection unit that detects distance to a predetermined position in the target area; a memory unit that stores distance data detected by the distance detection unit in association with position information of a plurality of small areas into which the target area is divided; a determination unit that analyzes image data acquired by the photographing unit to determine whether a predetermined specific phenomenon has occurred in the target area and the location of the occurrence; and a control unit that controls the focal length of the photographing unit. When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the photographing unit based on the distance data associated with a small area in which the specific phenomenon has occurred.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an imaging system, an imaging device, and an imaging method. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a technique for tracking and identifying a target (such as a person or a vehicle) using a camera (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-69342 Summary of the Invention [Problem to be solved by the invention]

[0004] When using a camera for surveillance, for example, the operator can adjust the direction and zoom magnification of a PTZ camera (pan-tilt-zoom camera), and then the camera's AF function (autofocus) can automatically adjust the focus.

[0005] However, it is difficult to instantly focus on a target within a wide surveillance area, and since it takes time to achieve focus, the accuracy of the focus adjustment decreases, and the image of the target often becomes blurry.

[0006] Therefore, the present disclosure has been made in consideration of the above technical problems, and its purpose is to provide an imaging system, an imaging device, and an imaging method that can focus on an object to be photographed efficiently with high accuracy. [Means for solving the problem]

[0007] The imaging system in the present disclosure is an imaging system that images a target area, an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon has occurred.

[0008] The imaging device in the present disclosure is an imaging device that images a target area, an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon has occurred.

[0009] The imaging method according to the present disclosure is a method for imaging a target area using an imaging system, comprising: The imaging system includes: an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon has occurred. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to provide an imaging system, an imaging device, and an imaging method that can focus on an object to be photographed efficiently with high accuracy. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an imaging system according to an embodiment of the present disclosure. [Figure 2] FIG. 1 is a block diagram showing an example of the configuration of an imaging device according to an embodiment of the present invention. [Figure 3] FIG. 4 is a flowchart illustrating an example of a photographing method according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0013] Until now, fixed-lens cameras have been widely used for surveillance. This is because the area being monitored is fixed and the need for an overall view is essential. Furthermore, since surveillance is performed by humans and actual events are confirmed by humans, no additional functionality is required. Meanwhile, advances in AI (artificial intelligence) image analysis have made it possible for cameras to identify monitored events without human intervention. These surveillance cameras require high-resolution images, which serve as the data for AI image analysis (since the process is automated). However, achieving high resolution across the entire surveillance area increases the cost of the surveillance camera itself. Furthermore, increasing resolution increases the volume of data to be analyzed by AI. Therefore, the time required for AI image analysis increases proportionally to the increase in resolution pixels. Therefore, maintaining the same timeframe as before requires a very high-performance CPU. An effective solution is to simplify AI image analysis across the entire surveillance area, identify the area where a specific event is occurring, zoom in on only that area, and allocate all available pixels to that area, thereby achieving high resolution through software. The camera that can do this is a PTZ camera that can pan, tilt, and zoom. This eliminates the need to improve the resolution of the camera itself, and also eliminates the need for a high-performance CPU to perform AI image analysis to analyze the entire screen.

[0014] However, if you zoom in on the identified area, you will not be able to obtain image data suitable for AI image analysis unless you perform a focusing operation. However, focusing on a PTZ camera generally takes several to several tens of seconds. During that time, the event you are monitoring may have ended or disappeared, so it is desirable to keep the focusing time as short as possible.

[0015] As mentioned above, with conventional surveillance cameras, it is difficult to instantly focus on a target in a wide surveillance area, and the image of the target is often blurred. Furthermore, when the target is moving, the autofocus must be performed while tracking the moving target, which makes it even more difficult.

[0016] A system according to an embodiment of the present invention can be used, for example, for automatic focus adjustment of a PTZ camera for security surveillance. The system of this embodiment can quickly adjust the focus to a target person or object, thereby enabling the acquisition of clear images. The system may also be applied to PTZ cameras used at construction sites. For example, the system can enhance safety by detecting a person or object under heavy machinery and appropriately zooming in to recognize the image. The system can also be used to prevent theft by detecting a person entering various construction sites and zooming in to recognize the person's face or confirm what they are carrying. Alternatively, the system may be used in a retail store or other store to zoom in on a cash register, specific product, clerk, customer, etc., and perform facial recognition, image recognition, and character recognition.

[0017] As shown in FIG. 1, the system of this embodiment includes a photographing device 100 equipped with a distance detection unit 10 and an imaging unit 20. The photographing device 100 can measure distances for each of the small regions B obtained by dividing the target area A into a predetermined number of parts (e.g., equal divisions, but the sizes do not have to be uniform), using the distance detection unit 10, and store the distances in a memory unit. It is preferable that the size (area) of the small regions B be set small in areas of the target area A where the elevation difference (distance from the camera) is large and large in areas where the elevation difference is small. In other words, the size of the small regions may be determined based on a pre-scan or prior area information, as described below. Reducing the size of the small regions B (dividing the target area A finely) increases the accuracy of distance data at each position, while increasing the size of the small regions B (dividing the target area A roughly) reduces the amount of calculation, thereby reducing the processing load. Specifically, multiple options for the small area B may be stored in advance, and a pre-scan or the like may be used to select an option that results in a small area size where the elevation difference exceeds a predetermined value, and an option that results in a large area size where the elevation difference does not exceed the predetermined value. The image capture device 100 measures the distance to a predetermined point P (one or more points) for each small area B. When measuring multiple points, the average value may be used as the distance to the small area B. The image capture device 100 in this example can be attached to any location, such as a wall, ceiling, or floor. The distance detection unit 10 is, for example, a laser rangefinder, but is not limited to this and may be another distance measurement sensor or a depth camera. The image capture unit 20 may be a PTZ camera. In this example, the direction of the distance detection unit 10 (measurement direction) and the direction of the image capture unit 20 (image capture direction) are arranged in the same direction. In this example, the lens of the laser rangefinder is arranged adjacent (close) to (directly adjacent to) the lens of the PTZ camera, but this is not limited to this and the distance detection unit 10 may be located in any position, above, below, left, or right. Although it is preferable to make the optical axis of the laser measurement meter and the optical axis of the camera coaxial, the optical axis of the laser measurement meter and the optical axis of the camera may be installed parallel to each other from the viewpoint of reducing production costs, etc. The distance at which the optical axis of the laser measurement meter and the optical axis of the camera intersect may be determined based on performance information of the camera.For example, if the camera's imaging range is assumed to be between 50 m and 200 m from the camera, the distance may be set to 125 m, which is in between, or to another distance such as 100 m or 150 m. The distance at which the optical axes intersect may be determined by the control unit based on the camera's performance information and a predetermined calculation formula. By synchronizing the orientation of the distance detection unit 10 (which is fixed) with the panning and tilting of the imaging unit 20 and displacing it in the same way, the optical axis of the PTZ camera and the optical axis of the laser rangefinder can always be aligned. In this example, the distance detection unit 10 and imaging unit 20 are provided on a movable part of the imaging device 100 and operate together.

[0018] A laser rangefinder is a measuring instrument that emits a single beam of light in a direction of illumination (for example, forward), measures the reflected light, and can measure the distance to the reflecting point. Using a laser rangefinder can reduce costs while ensuring accuracy in distance measurement.

[0019] 2 shows an example of a functional block diagram of an image capturing device 100 included in the system of this embodiment. The image capturing device 100 includes a distance detection unit 10, an imaging unit 20, a control unit 30, a storage unit 40, and a communication unit 50. The distance detection unit 10, the imaging unit 20, the control unit 30, the storage unit 40, and the communication unit 50 may be implemented in a single device, or some of them may be implemented in separate devices and communicate with each other. The image capturing device 100 may include only some of the components shown in the figure, or may include other components.

[0020] When the image capturing device 100 receives various request signals or based on information stored in the storage unit, the control unit 30 executes processing according to a program, and outputs the processing results (for example, various information such as generated images and sounds) from the output unit as appropriate, transmits them to another information processing device (such as a smartphone or tablet terminal held by a worker), or stores them in the storage unit. Note that part of the program may be transmitted to another information processing device and executed on that other information processing device.

[0021] The control unit 30 transfers data between each unit and controls the entire photographing device 100, and is realized by the CPU (Central Processing Unit) and GPU (Graphics Processing Unit) executing programs stored in a specified memory (storage unit).

[0022] The control unit 30 controls the operations (horizontal panning and vertical tilting) of the imaging unit 20 and the distance detection unit 10. The control unit 30 also controls the zoom operation that involves expanding and contracting the imaging range of the imaging unit 20. The control unit 30 can control the operations of the imaging unit 20 and the distance detection unit 10 based on conditions stored in the storage unit. The control unit 30 can control the operations of the imaging unit 20 and the distance detection unit 10 based on instruction information from an external device (transmitted via the communication unit), input information from a user (system administrator, operator, etc.), etc.

[0023] The control unit 30 controls the distance detection unit 10. The control unit 30 can control the distance detection unit 10 based on conditions stored in the storage unit, instruction information from an external device, input information from a user, etc. The control unit 30 functions as a determination unit that determines the occurrence of a specific phenomenon. The determination unit that determines the occurrence of a specific phenomenon may be configured with other devices, etc. For example, the occurrence of a specific event may be determined by detecting a person using a human presence sensor. Such a detection device may be any other sensor device, such as an infrared sensor, a distance sensor, a contact sensor, a temperature sensor, a camera, etc. This can detect the presence or absence of a person, intrusion, approach, contact, and the occurrence of other phenomena including natural phenomena, and trigger photography.

[0024] The storage unit 40 has a nonvolatile storage device which is a read-only storage area in which a system program is stored, and a volatile storage device which is a rewritable storage area used as a work area for arithmetic processing by the control unit 30. The nonvolatile storage device is realized by, for example, a ROM (Read Only Memory), a flash memory, or a hard disk, while the volatile storage device is realized by, for example, a RAM (Random Access Memory), a VRAM (Video Random Access Memory), or the like.

[0025] The memory unit 40 can store various information such as information acquired by the distance detection unit 10, information acquired by the imaging unit 20, information regarding the monitored area, small area, control condition information, and information generated by the control unit.

[0026] The storage unit 40 may store information about an information processing device (such as a smartphone or tablet terminal) that transmits the output data. The output data may include, for example, image data (including video and still images) acquired by the imaging unit, information generated based on the image (results of image analysis), and information associating the occurrence of a specific phenomenon with the image data, the time of occurrence, and the location of occurrence.

[0027] Here, the image capturing device 100 may include an input unit for a user to input information and an output unit for outputting information. The input unit may be, for example, a keyboard, a mouse, a touch panel, or a microphone for voice input. The output unit may be, for example, a speaker for outputting voice, a display for displaying images, a touch panel, etc.

[0028] The communication unit 50 is connected to a network including the Internet in order to transmit and receive information to and from external devices. The communication unit 50 may include a short-range communication interface such as Bluetooth (registered trademark) or BLE (Bluetooth Low Energy). Via the communication unit 50, output data can be transmitted to other information processing devices and signals can be received from other information processing devices.

[0029] FIG. 3 shows an example of a method for capturing images using this system. The image capturing device 100 performs a pre-scan (S1) as a preparatory operation before starting monitoring. In the pre-scan, the optical axis of the PTZ camera and the optical axis of the laser rangefinder are directed at the entire area being monitored by the PTZ camera at predetermined intervals (e.g., 0.5° intervals, 1° intervals, etc.) in both the horizontal and vertical rotation directions, and distances are measured using the laser rangefinder. The measured information is stored in a memory unit (S2). For example, information on the measured directions (horizontal and vertical directions) is stored in association with the distance data of the measurement results. This information may be stored by assigning an identification number to each measurement direction (or each small area B) and as an "identification number (0001, 0002, etc.)," ​​"measurement direction (10° horizontal, 30° vertical)," "measurement result distance (20 m)," and "lens adjustment parameters."

[0030] Prescanning allows distances to be measured for each of a specified number of divided areas, such as for each area that is 1 / 10,000th of the total resolution. However, to prevent sudden changes in distance data for neighboring areas, a smoothing process is performed on the pre-measured distance values ​​for each area. Lens adjustment parameters for focusing on each divided small area are then calculated and recorded in a parameter table in advance. The lens adjustment parameters can be calculated by applying distance values ​​to a predetermined calculation formula depending on the performance of the camera as the imaging unit.

[0031] Then, monitoring is performed to detect a specific phenomenon (S3). Specifically, the control unit performs image analysis (which may be AI image analysis) on the entire monitored area based on the image information acquired by the imaging unit. For example, the control unit can detect the presence or absence of moving objects (people, automobiles, bicycles) in the monitored area, whether they are moving, their direction of movement, and their speed of movement. In the case of people, the control unit estimates their gender, age, height, weight, clothing, and the presence and type of clothing (glasses, hats, helmets). If the estimated information satisfies predetermined conditions, the control unit determines that a specific phenomenon (anomaly) has occurred. The conditions for the specific phenomenon are stored in advance in the storage unit. For example, if a person wearing black sunglasses, a mask, and a hat is detected, an anomaly can be determined. Alternatively, if a moving object (such as a car, motorcycle, or electric scooter) traveling at a speed equal to or greater than a predetermined speed (30 km / h, 50 km / h, or 100 km / h) is detected, an anomaly can be determined to have occurred. The conditions for anomaly determination in the storage unit can be set or updated as appropriate by the user through user input.

[0032] When the control unit determines that an abnormality has occurred, it identifies the area where the abnormality has occurred, controls the imaging unit to adjust the focal length so that only the identified area is photographed (S4), and photographs the area (S5). At this time, the control unit may adjust the orientation of the imaging unit in addition to adjusting the focal length. Specifically, the control unit analyzes the image and determines which of the 10,000 divided areas the abnormality is located in based on the position (coordinates) of the area on the image where the abnormality has occurred by comparing it with information in the memory unit, and controls the orientation and zoom of the imaging unit (adjusts the focal length) by referring to the "measurement direction," "lens adjustment parameters," etc. of that area. This allows the imaging unit to instantly focus.

[0033] Note that pre-scanning may be performed at predetermined intervals to update the information. This allows for responding to changes in the topography, buildings, and fixed landscape objects in the monitored area. The predetermined interval may be a fixed period, such as once per day, week, or month, or may be determined when a predetermined condition is met. If the period is fixed, the interval for acquiring image data may be changed depending on the time of day (morning, afternoon, hourly, etc.) or the season. If the period is not fixed, the interval may be determined, for example, when a user instruction (input information) is received, or when a change in the subject, such as the topography, buildings, or fixed landscape objects, in the monitored area is detected based on the image captured by the imaging unit. Such changes can be determined by image analysis, comparing past image data captured from the same shooting direction with current data to determine whether there is a difference (e.g., whether the difference exceeds a threshold).

[0034] In this embodiment, the imaging unit may operate by tracking the movement of a specific moving object. In this case, the area in which the moving object is located may be identified from image data, and the focal length parameter of that area may be referenced to adjust the focus (focal length) while also adjusting the orientation of the optical axis of the imaging unit. Furthermore, in this case, the control unit may predict the moving object's position a predetermined time later based on information about the moving direction and moving speed of the moving object, and adjust the focal length of the imaging unit by reference to the focal length parameter of the area in that position. For example, if the control unit predicts that the moving object will be located in a specific area one second from now, it may adjust the focal length of the imaging unit based on the focal length parameter of the predicted area rather than the area in which the moving object currently exists. Such position prediction conditions based on the moving direction and moving speed of the moving object and information on the operating conditions of the imaging unit based on the predicted values ​​are stored in advance in a storage unit. Information on the operating conditions of the imaging unit based on the predicted values ​​may include time information, such as how many seconds into the future the moving object's position is predicted to be and used to adjust the focus, and each condition may be set in association with the type of moving object (person, automobile, etc.). Similarly, position prediction conditions may also be set for each type of moving object. The direction and speed of a moving object can be calculated by comparing multiple image data taken at different times to detect changes (difference values) in the position (coordinates) of a specific moving object, or by calculating the speed from the moving time and distance.

[0035] As described above, the photographing system, photographing device, and photographing method of this embodiment photograph a target area related to a target area. The photographing system includes an image capturing unit that captures the target area, a distance detection unit that detects the distance to a predetermined position in the target area, a memory unit that stores the distance data detected by the distance detection unit in association with position information of multiple small areas obtained by dividing the target area, a determination unit that analyzes image data acquired by the image capturing unit to determine whether a predetermined specific phenomenon has occurred in the target area and the location of the occurrence, and a control unit that controls the focal length of the image capturing unit. When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the image capturing unit based on the distance data associated with the small area where the specific phenomenon has occurred. This configuration allows for efficient focusing on the photographed object with high accuracy.

[0036] The imaging unit may be a PTZ camera whose imaging direction can be changed horizontally and vertically, thereby enabling imaging of a wide range.

[0037] The distance detection unit may be a laser rangefinder, which allows for highly accurate distance measurement at a relatively low cost.

[0038] The imaging unit and the distance detection unit may be arranged so that the imaging direction of the imaging unit and the detection direction of the distance detection unit are substantially the same, thereby enabling efficient distance detection and imaging in a predetermined direction.

[0039] The detection direction of the distance detection unit may be changed in synchronization with the change in the shooting direction of the imaging unit, thereby enabling more efficient distance detection and shooting in a predetermined direction.

[0040] The storage unit may store information about the image capturing direction of the image capturing unit and information about the small area in association with each other, thereby making it possible to grasp the relationship between the orientation of the image capturing unit and the image capturing target area.

[0041] The distance detection unit may detect the distance to the target area at predetermined intervals and update the information in the storage unit. This allows for highly accurate imaging in accordance with changes in the target area.

[0042] The determination unit may determine whether the specific phenomenon has occurred based on at least one of the speed and direction of movement of a specific moving object estimated from the image data for a specific period of time, thereby enabling detection of the specific phenomenon g according to the movement of the moving object.

[0043] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person skilled in the art of the present disclosure can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0044] The devices described herein may be implemented as a single device, or may be implemented as multiple devices (e.g., cloud servers) partially or entirely connected via a network. For example, the control unit and storage unit of a server may be implemented as different servers connected to each other via a network. Furthermore, the information processing performed by the above-described devices, servers, etc. may include, for example, some processing using so-called machine learning, such as deep learning. Furthermore, the devices may be terminal devices (information processing devices) called edge devices, which themselves are equipped with artificial intelligence (AI) capable of making decisions.

[0045] The series of processes performed by the devices described herein may be implemented using software, hardware, or a combination of software and hardware. A computer program for implementing each function of the user terminal and server according to this embodiment may be created and installed on a PC or the like. A computer-readable recording medium on which such a computer program is stored may also be provided. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The computer program may also be distributed, for example, via a network, without using a recording medium.

[0046] Furthermore, the processes described herein using flowchart diagrams do not necessarily have to be performed in the order shown. Some process steps may be performed in parallel. Additional process steps may be employed, and some process steps may be omitted.

[0047] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0048] In the above example, the occurrence of a specific phenomenon is used as a trigger to control the image capturing unit, but this is not limiting. The image capturing unit may also be controlled based on a schedule pre-stored in the storage unit. That is, the image capturing unit may capture images of pre-stored positions at pre-stored times. In this case, too, the focal length can be controlled based on the distance data to each pre-stored position, enabling efficient, rapid, and highly accurate image capturing.

[0049] The following configurations also fall within the technical scope of the present disclosure. (Item 1) 1. An imaging system for imaging a target area, comprising: an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon has occurred. (Item 2) Item 1. The imaging system according to item 1, wherein the imaging unit is a PTZ camera whose imaging direction can be changed in the horizontal and vertical directions. (Item 3) 3. The photographing system according to item 1 or 2, wherein the distance detection unit is a laser rangefinder. (Item 4) 3. The photographing system according to item 1 or 2, wherein the imaging unit and the distance detection unit are arranged so that an imaging direction of the imaging unit and a detection direction of the distance detection unit substantially coincide with each other. (Item 5) 5. The photographing system according to item 4, wherein the detection direction of the distance detection unit changes in synchronization with a change in the photographing direction of the imaging unit. (Item 6) 3. The photographing system according to item 1 or 2, wherein the storage unit stores information about the photographing direction of the imaging unit and information about the small region in association with each other. (Item 7) 3. The photographing system according to item 1 or 2, wherein the distance detection unit detects the distance to the target area at predetermined intervals and updates the information in the storage unit. (Item 8) 3. The photographing system according to item 1 or 2, wherein the determination unit determines whether the specific phenomenon has occurred based on at least one of a moving speed and a moving direction of a predetermined moving object estimated from the image data for a predetermined period. (Item 9) An imaging device for imaging a target area, an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon occurred. (Item 10) 1. A method for photographing a target area using an imaging system, comprising: The imaging system includes: an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, a control unit that controls a focal length of the imaging unit based on the distance data associated with the small region in which the specific phenomenon occurred when the determination unit determines that the specific phenomenon has occurred. [Explanation of symbols]

[0050] 10 Distance detection unit 11 Reading area 20 Imaging unit 30 Control Unit 40 Storage section 100 Imaging device

Claims

1. 1. An imaging system for imaging a target area, comprising: an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon has occurred.

2. The photographing system according to claim 1 , wherein the imaging unit is a PTZ camera whose photographing direction can be changed in the horizontal and vertical directions.

3. The photographing system according to claim 1 , wherein the distance detection unit is a laser rangefinder.

4. The photographing system according to claim 1 , wherein the imaging section and the distance detection section are arranged so that an imaging direction of the imaging section and a detection direction of the distance detection section substantially coincide with each other.

5. The photographing system according to claim 4 , wherein the detection direction of said distance detection unit changes in synchronization with a change in the photographing direction of said imaging unit.

6. The photographing system according to claim 1 , wherein the storage section stores information about the photographing direction of the image capturing section and information about the small area in association with each other.

7. The photographing system according to claim 1 , wherein the distance detection unit detects the distance to the target area at predetermined intervals and updates the information in the storage unit.

8. The photographing system according to claim 1 , wherein the determining unit determines whether the specific phenomenon has occurred based on at least one of a moving speed and a moving direction of a predetermined moving object estimated from the image data for a predetermined period of time.

9. An imaging device for imaging a target area, an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, When the determination unit determines that the specific phenomenon has occurred, the control unit controls the focal length of the imaging unit based on the distance data associated with the small area in which the specific phenomenon occurred.

10. 1. A method for photographing a target area using an imaging system, comprising: The imaging system includes: an imaging unit that captures an image of the target area; a distance detection unit that detects a distance to a predetermined position in the target area; a storage unit that stores the distance data detected by the distance detection unit in association with position information of a plurality of small regions obtained by dividing the target region; a determination unit that analyzes the image data acquired by the imaging unit and determines whether a predetermined specific phenomenon has occurred in the target area and the location where the phenomenon has occurred; a control unit that controls a focal length of the imaging unit, a control unit that controls a focal length of the imaging unit based on the distance data associated with the small region in which the specific phenomenon occurred when the determination unit determines that the specific phenomenon has occurred.

Images