Patent Description:
Nowadays, monitors are installed in many places. Existing monitor systems can merely be used for simple shooting, which facilitates invocation in later stage. But concerning the invocation of related monitors in real life, it means track(s) of one/some preset person need to be confirmed, this confirmation method however shows apparent hysteresis. Moreover, an accurate trace on the preset person and thus an actual track of the preset person will not be achieved due to absence of a record of a previous track of the preset person, which may bury a potential security risk to the safety of an area where the preset person is captured and users in the area.

<NPL>, discloses the integration of multiple, potentially heterogeneous, smart cameras into a distributed system for computer vision and sensor fusion, and discusses the requirements on middleware for distributed smart cameras and the services such a middleware has to provide.

<NPL>, discloses a multicamera tracking method on distributed, embedded smart cameras. Smart cameras combine video sensing, processing, and communication on a single embedded device which is equipped with a multiprocessor computation and communication infrastructure. The multicamera tracking approach focuses on a fully decentralized handover procedure between adjacent cameras. The basic idea is to initiate a single tracking instance in the multicamera system for each object of interest. The tracker follows the supervised object over the camera network, migrating to the camera which observes the object. Thus, no central coordination is required resulting in an autonomous and scalable tracking approach.

<NPL>, discloses the integration of multi-camera tracking into an agent-based framework, which features autonomous task allocation for smart cameras targeting trafc surveillance. Since The target platforms are distributed embedded systems with limited resources, the trackers may only be active, if the target is in the camera's field of view. Consequently, the tracking algorithm has to migrate from camera to camera in order to follow the target, whereas the decision when and whereto the migration takes place is reached autonomously by the tracker. Consequently, no central control host is required. Different strategies are further presented on when to migrate a tracker, and how to determine the camera which will observe the tracked object subsequently.

<NPL>, discloses a comprehensive framework for tracking coarse human models from sequences of synchronized monocular grayscale images in multiple camera coordinates. It demonstrates the feasibility of an end-to-end person tracking system using a unique combination of motion analysis on 3D geometry in different camera coordinates and other existing techniques in motion detection, segmentation, and pattern recognition. The system starts with tracking from a single camera view. When the system predicts that the active camera will no longer have a good view of the subject of interest, tracking will be switched to another camera which provides a better view and requires the least switching to continue tracking. The nonrigidity of the human body is addressed by matching points of the middle line of the human image, spatially and temporally, using Bayesian classification schemes. Multivariate normal distributions are employed to model class-conditional densities of the features for tracking, such as location, intensity, and geometric features. Limited degrees of occlusion are tolerated within the system.

The invention is defined in the independent claims, to which the reader is now directed. Preferred or advantageous embodiments are set out in the dependent claims. The embodiments of the present disclosure provide a method and a device for obtaining a movement track.

The technical solutions provided by the embodiments of the present disclosure may provide advantages as follows.

The technical solutions provided by the embodiments of the present disclosure may predict the movement track of the preset person according to the current geographic location of the current camera device which captures the target image information and the motion state of the preset person when determines that the preset person information exists in the target image information, and activate the target camera devices along the movement track so as to factually shooting the preset person in time to accurately determine a final actual movement track of the preset person, and record the actual movement track of the preset person so as to determine the trace of preset person according to the actual movement track, which avoids cases that an accurate trace on the preset person and thus an actual track of the preset person may not be achieved in the later stage due to absence of a record of a previous track of the preset person, and avoids potential security risks to an area where the preset person is captured and users in the area.

It should be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and shall not be construed to limit the present disclosure.

Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings. The implementations set forth in the following description of example embodiments do not represent all implementations consistent with the invention. Instead, they are merely examples of apparatuses and methods consistent with aspects related to the invention as recited in the appended claims.

To solve the technical problems described above, embodiments of the present disclosure provide a method for obtaining a movement track, which may be used in a program, a system or a device for obtaining the movement track. Besides, an executive object corresponding to the method may be a terminal with a shooting function, e.g. a terminal of a monitoring system installed in XX building / XX community. Referring to <FIG>, the method includes the following steps S101 to S105.

In step S101, target image information captured is obtained. That is, target image information captured by a camera device can be obtained.

The current camera device for shooting the target image information may be a camera of the monitoring system in XX building / XX community, or a cellphone, a tablet or a computer and so forth hold by someone, and the target image information may be one or more image information shot currently or in a certain period.

In step S102, it is detected whether preset person information exists in the target image information.

The preset person information includes but not be limited to at least one of preset image information, a preset action, a preset gait and a preset expression, e.g. further includes feature information of a person, such as a mole on the face, a certain face frame and a certain eye shape and so forth.

The preset image information may refer to image information of specific person saved in a cellphone or image information of latest announced escaped criminals and suspects and so forth downloaded automatically from local security system.

The preset action includes but not be limited to at least one of a knife related action (e.g. an action with knife), a gun related action (e.g. an action with gun), an action of hitting people and a dragging action.

The preset gait may be a staggering gait, a running gait, a walking gait and so forth, and the preset expression may be a surprise, panic, fear or grim expression and so forth.

It may be determined whether the preset person corresponding to preset person information exists in the target image information by detecting whether preset person information exists in the target image information, and if the preset person exists in the target image information, the preset person may be the specific person the user wants to track, or the escaped criminals or suspects and so forth, according to the specific definition to the preset person information.

In step S <NUM>, a current geographic location of a current camera device capturing the target image information is obtained, if the preset person information exists in the target image information.

In step S104, the movement track of a preset person is predicted according to the current geographic location and a motion state of the preset person corresponding to the preset person information, the motion state may be directly obtained or speculated from the preset gait of the preset person information.

The current geographic location of the current camera device for capturing the target image information can be automatically obtained if the above preset person information exists in the target image information, such that the movement track of the preset person can be automatically and accurately predicted according to the current geographic location and the motion state of the preset person corresponding to the preset person information.

In step S105, the target camera device along the movement track is activated.

The target camera device and the current camera device can be positioned in the same or different monitoring system(s), and the target camera device may be a camera or devices with shooting function (such as cellphone) and may be connected with the current camera device by wired or wireless way, such as by WiFi network, Bluetooth or Mobile data network.

After the movement track is predicted, since the actual movement track of the preset person may change, the target camera device along the movement track may be activated so as to factually shoot the preset person in time to accurately determine a final actual movement track of the preset person, and record the actual movement track of the preset person so as to determine the trace of preset person according to the actual movement track, which avoids cases that an accurate trace on the preset person and thus an actual track of the preset person may not be achieved in the later stage due to absence of a record of a previous track of the preset person, and avoids potential security risks to an area where the preset person is captured and users in the area.

Furthermore, image data which shows the actual movement track of the preset person may be further obtained by activating the target camera device, such that the movement track of the preset person may be vividly watched in later stage through the image data.

As shown in <FIG>, in an embodiment, step S104 shown in <FIG> is executed as follows.

In step A1, a current location of the preset person is judged or determined according to the current geographic location and a location of the preset person information in the target image information.

After the current geographic location is obtained, since the current camera device corresponds to one area, so the preset person may appear in any position of the shooting area. Therefore, when the preset person positions at different locations, locations of the preset person information in the target image information are different, and ratios in size of the location area the preset person information positioned to the target image information are different. Thus, the current person location of the preset person, i.e. an actual position coordinate of the preset person, may be accurately judged or determined according to the current geographic location and the location of the preset person information in the target image information.

In step A2, the movement track of the preset person is predicted according to the current person location and the motion state. The motion state includes at least one of a current motion mode and a historical motion parameter of the preset person. The current motion mode may be walking, cycling, riding electric bike, driving or taking ferry and so forth. The historical motion parameter is a historical moving rate and a historical moving direction of the preset person at the moment over the past period of time when the target image information including the preset person information is captured.

The movement track of the preset person may be accurately predicted according to the actual current person location and the motion state of preset person.

Specifically, since different current motion states correspond to different motion parameters, therefore an approximate moving rate and moving direction may be obtained according to the current motion state, and thus the movement track of the preset person is accurately predicted; or the movement track of the preset person may be predicted by some algorithms used for movement track prediction, such as Kalman filter algorithm, after the historical motion parameter is obtained.

As shown in <FIG>, in an embodiment, step S105 shown in <FIG> described above is executed as follows.

In step B <NUM>, camera devices along the movement track is obtained.

In step B2, the target camera device from which the distance to the current geographic location is less than or equal to a preset distance is determined from the camera devices.

The target camera device is in a range taking the current geographic location as a center and the preset distance as a radius, and the preset distance may be fixed (such as <NUM>) or changeable.

In step B3, the target camera device is activated to shoot the preset person and the movement track is updated when the preset person is captured.

Since there may be multiple camera devices along the movement track and the camera devices located far away from the preset person cannot capture the preset person in a short time, therefore, the nearer target camera device from which the distance to the current geographic location is less than or equal to the preset distance may be chosen, and to which an activation instruction may be transmitted, so that they are activated. Thus, the preset person is shot by the target camera device when the preset person moves into a shooting area of the target camera device. Besides, the current person location may be automatically determined again when the preset person is captured, so that the predicted movement track is in time updated, such as being corrected and modified and so on.

Additionally, the movement track of the preset person may be continually updated, corrected and modified by continually repeating the steps above. Thus the latest actual movement track may be obtained.

As shown in <FIG>, in an embodiment, the method describe above further includes the following step.

In step S401, other camera devices along the movement track, from which the distance to the current geographic location is greater than the preset distance, is activated, if the preset person is not captured after the target camera device is activated.

If the preset person is not captured after the target camera device is activated, it indicates that the preset person is not tracked by the target camera device nearby. In order to track the movement track of the preset person, other camera devices along the movement track, from which the distance to the current geographic location is greater than the preset distance, may be activated for further tracking the movement track of the preset person, such that the actual movement track of preset person is obtained, which is convenient for invocation and tracking in later stage.

As shown in <FIG>, in an embodiment, before step B2 is executed, the method described above further includes the following steps.

In step S501, a current motion parameter of the preset person is predicted according to the motion state, the current motion parameter comprises a current moving rate and a current moving direction.

Since different motion states correspond to different motion parameters, and the motion parameter of the preset person shows relative stability and consistency instead of sudden great change in a certain period under the same motion state, therefore, the current motion parameter of the preset person may be predicted according to the motion state thereof.

In step S502, the preset distance is determined according to current motion parameter and the current geographic location.

Since different motion states correspond to different motion parameters, the numbers of camera devices in different preset distances are always different, and different numbers of camera devices are required due to different current motion parameters of the preset person (e.g. when the moving rate of the preset person is fast, the number of camera device required is large in case the preset person is missed by the camera devices), therefore, the preset distance which is suitable to the current motion parameter and the current geographic location is determined according to the current motion parameter and the current geographic location after the current motion parameter is predicted depending on the motion state, so as to adopt suitable number of camera devices to shooting the preset person and obtain the latest movement track of the preset person in time.

Furthermore, as the numbers of the camera devices in the same distance are different depending on different geographic locations, e.g. in the same distance, the number of the camera devices in a mountainous area is much less than that in an urban area. Thus, the current geographic location may be also considered when determining the preset distance.

Step B2 shown in <FIG> described above is executed as follows.

The target camera device, from which the distance to the current geographic location is less than or equal to the preset distance and whose direction corresponds to the current moving direction, is determined from the camera devices.

The target camera device, from which the distance to the current geographic location is less than or equal to the preset distance and whose direction corresponds to (i.e. be consistent with) the current moving direction, is determined from the camera devices when determining the target camera device, such that the preset person is effectively captured so as to track and confirm the actual movement track of the preset person with not only the smallest number of the target camera devices, but with a decreased power consumption.

In an embodiment, the preset person information includes: at least one of a preset image information, a preset action, a preset gait and a preset expression.

The preset person information includes but not be limited to at least one of the preset image information, the preset action, the preset gait and the preset expression, e.g. may also be feature information of a person, such as a mole on the face, a certain face frame and a certain eye shape and so forth.

The embodiments of the invention further provides a device for obtaining a movement track which corresponds to the above method for obtaining a movement track provided according to the embodiments of the preset disclosure. As shown in <FIG>, the device includes: a first obtaining module <NUM>, a detecting module <NUM>, a second obtaining module <NUM>, a first predicting module <NUM>, and a first activating module <NUM>.

The first obtaining module <NUM> is configured to obtain target image information captured.

The detecting module <NUM> is configured to detect whether preset person information exists in the target image information.

The second obtaining module <NUM> is configured to obtain a current geographic location of a current camera device capturing the target image information if the preset person information exists in the target image information.

The first predicting module <NUM> is configured to predict the movement track of a preset person according to the current geographic location and a motion state of the preset person corresponding to the preset person information, the motion state may be directly obtained or speculated from the preset gait of the preset person information.

The current geographic location of the current camera device capturing the target image information can be automatically obtained if the above preset person information exists in the target image information, such that the movement track of the preset person can be automatically and accurately predicted according to the current geographic location and the motion state of the preset person corresponding to the preset person information.

The first activating module <NUM> is configured to activate the target camera device along the movement track.

After the movement track is predicted, since the actual movement track of the preset person may change, the target camera device along the movement track may be activated so as to factually captured the preset person in time to accurately determine a final actual movement track of the preset person, and record the actual movement track of the preset person so as to determine the trace of preset person according to the actual movement track, which avoids cases that an accurate trace on the preset person and thus an actual track of the preset person may not be achieved in the later stage due to absence of a record of a previous track of the preset person, and avoids potential security risks to an area where the preset person is captured and users in the area.

As shown in <FIG>, in an embodiment, the first predicting module <NUM> may include: a judging sub-module <NUM> and a predicting sub-module <NUM>.

The judging sub-module <NUM> is configured to judge a current person location of the preset person according to the current geographic location and a location of the preset person information in the target image information.

After the current geographic location is obtained, since the current camera device corresponds to one shooting area, so the preset person may appear in any position of the shooting area. Therefore, when the preset person positions at different locations, locations of the preset person information in the target image information are different, and ratios in size of the location area the preset person information positioned to the target image information are different. Thus, the current person location of the preset person, i.e. an actual position coordinate of the preset person, may be accurately judged according to the current geographic location and the location of the preset person information in the target image information.

The predicting sub-module <NUM> is configured to predict the movement track of the preset person depending on the current person location and the motion state of the preset person, in which the motion state includes at least one of the current motion mode and the historical motion parameter of the preset person.

As shown in <FIG>, in an embodiment, the first activating module <NUM> includes: an obtaining sub-module <NUM>, a determining sub-module <NUM>, and a processing sub-module <NUM>.

The obtaining sub-module <NUM> is configured to obtain camera devices along the movement track.

The determining sub-module <NUM> is configured to determine, from the camera devices, the target camera device from which the distance to the current geographic location is less than or equal to a preset distance.

The processing sub-module <NUM> is configured to activate the target camera device to shoot the preset person and to update the movement track when the preset person is captured.

Since there may be multiple camera devices along the movement track and the camera devices located far away from the preset person cannot shoot the preset person in a short time, therefore, the nearer target camera device from which the distance to the current geographic location is less than or equal to the preset distance may be chosen, and to which an activation instruction may be transmitted, so that they are activated. Thus, the preset person is shot by the target camera device when the preset person moves into a shooting area of the target camera device. Besides, the current person location may be automatically determined again when the preset person is captured, so that the predicted movement track is in time updated, such as being corrected and modified and so on.

Additionally, the movement track of the preset person can be continually updated, corrected and modified by continually repeating the steps above. Thus the latest actual movement track may be obtained.

As shown in <FIG>, in an embodiment, the device described above further includes:
a second activating module <NUM>.

The second activating module <NUM> is configured to activate other camera devices along the movement track, from which the distance to the current geographic location is greater than the preset distance, if the preset person is not captured after the target camera device is activated.

As shown in <FIG>, in an embodiment, the device described above further includes: a second predicting module <NUM> and a determining module <NUM>.

The second predicting module <NUM> is configured to predict a current motion parameter of the preset person according to the motion state before the target camera device from which the distance to the current geographic location is less than or equal to a preset distance is determined from the camera devices, in which the current motion parameter includes one or more of a current moving rate and a current moving direction.

The determining module <NUM> is configured to determine the preset distance according to the current motion parameter and the current geographic location.

Since different motion states correspond to different motion parameters, the numbers of camera devices in different preset distances are always different, and different numbers of camera devices are required due to different current motion parameters of the preset person (e.g. when the moving rate of the preset person is fast, the number of camera device required is large in case the preset person is missed by the camera devices), therefore, the preset distance which is suitable to the current motion parameter and the current geographic location may be determined according to the current motion parameter and the current geographic location after the current motion parameter is predicted depending on the motion state, so as to adopt suitable number of camera devices to shoot the preset person and obtain the latest movement track of the preset person in time.

Furthermore, as the numbers of the camera devices in the same distance are different depending on different geographic locations, e.g. in the same distance, the number of the camera devices in a mountainous area is much less than that in an urban area, thus, the current geographic location may be also considered when determining the preset distance.

The determining sub-module <NUM> described above includes: a determining unit.

The determining unit is configured to determine, from the camera devices, the target camera device from which the distance to the current geographic location is less than or equal to the preset distance and whose direction corresponds to the current moving direction.

The target camera device, from which the distance to the current geographic location is less than or equal to the preset distance and whose direction corresponds to (i.e. be consistent with) the current moving direction, is determined from the camera devices when determining the target camera device, such that the preset person may be effectively shot so as to track and confirm the actual movement track of the preset person with not only the smallest number of the target camera devices, but with a decreased power consumption.

In an embodiment, the preset person information includes at least one of the preset image information, the preset action, the preset gait and the preset expression.

According to the third aspect useful to understand the invention, there is provided a device for obtaining a movement track, the device includes: a processor and a memory configured to store an instruction executable by the processor.

The processor described above predicts the movement track of the preset person according to the current geographic location and the motion state of the preset person corresponding to the preset person information by:.

The processor described above activates the target camera device along the movement track by:.

The processor described above may be further configured to:
activate other camera devices along the movement track, from which the distance to the current geographic location is greater than the preset distance, if the preset person is not captured after the target camera device is activated.

Before the target camera device from which the distance to the current geographic location is less than or equal to the preset distance is determined from the camera devices, the processor described above:.

The processor described above determines, from the camera devices, the target camera device from which the distance to the current geographic location is less than or equal to a preset distance by:
determining, from the camera devices, the target camera device from which the distance to the current geographic location is less than or equal to the preset distance and whose direction corresponds to the current moving direction.

The preset person information includes at least one of the preset image information, the preset action, the preset gait and the preset expression.

<FIG> is a block diagram showing a device <NUM> for obtaining a movement track according to an example embodiment, the device applies to a terminal device. For example, the device <NUM> may be a mobile phone, a computer, a digital broadcasting terminal, a messaging device, a game console, a tablet device, a medical equipment, a fitness equipment, a Personal Digital Assistant PDA, etc..

Referring to <FIG>, the device <NUM> may include the following one or at least two components: a processing component <NUM>, a memory <NUM>, a power component <NUM>, a multimedia component <NUM>, an audio component <NUM>, an Input/Output (I/O) interface <NUM>, a sensor component <NUM>, and a communication component <NUM>.

The processing component <NUM> may include one or at least two processors <NUM> to execute instructions to perform all or part of the steps in the above described methods. Moreover, the processing component <NUM> may include one or at least two modules which facilitate the interaction between the processing component <NUM> and other components.

Examples of such data include instructions for any storage objects or methods operated on the device <NUM>, contact data, phonebook data, messages, pictures, video, etc. The memory <NUM> may be implemented using any type of volatile or non-volatile memory devices, or a combination thereof, such as a static random access memory (SRAM), an electrically erasable programmable read-only memory (EEPROM), an erasable programmable read-only memory (EPROM), a programmable read-only memory (PROM), a read-only memory (ROM), a magnetic memory, a flash memory, a magnetic or optical disk.

The power component <NUM> may include a power management system, one or at least two power sources, and any other components associated with the generation, management, and distribution of power in the device <NUM>.

The touch panel includes one or at least two touch sensors to sense touches, swipes, and other gestures on the touch panel. The touch sensors may not only sense a boundary of a touch or swipe action, but also sense a duration time and a pressure associated with the touch or swipe action. The front camera and/or the rear camera may receive external multimedia data while the device <NUM> is in an operation mode, such as a shooting mode or a video mode.

The audio component <NUM> is configured to output and/or input audio signals. For example, the audio component <NUM> includes a microphone (MIC) configured to receive an external audio signal when the device <NUM> is in an operation mode, such as a call mode, a recording mode, and a voice recognition mode. The received audio signal may be further stored in the memory <NUM> or transmitted via the communication component <NUM>. In some embodiments, the audio component <NUM> further includes a speaker to output audio signals.

The I/O interface <NUM> provides an interface for the processing component <NUM> and peripheral interface modules, such as a keyboard, a click wheel, buttons, and the like.

The sensor component <NUM> includes one or at least two sensors to provide status assessments of various aspects of the device <NUM>. For instance, the sensor component <NUM> may detect an open/closed status of the device <NUM> and relative positioning of components (e.g. the display and the keypad of the device <NUM>). The sensor component <NUM> may also detect a change in position of the device <NUM> or of a component in the device <NUM>, a presence or absence of user contact with the device <NUM>, an orientation or an acceleration/deceleration of the device <NUM>, and a change in temperature of the device <NUM>.

The communication component <NUM> is configured to facilitate wired or wireless communication between the device <NUM> and other devices. The device <NUM> can access a wireless network based on a communication standard, such as WIFI, <NUM>, or <NUM>, or a combination thereof. In one example embodiment, the communication component <NUM> receives a broadcast signal or broadcast associated information from an external broadcast management system via a broadcast channel. In one example embodiment, the communication component <NUM> further includes a near field communication (NFC) module to facilitate short-range communications. For example, the NFC module may be implemented based on a radio frequency identification (RFID) technology, an infrared data association (IrDA) technology, an ultra-wideband (UWB) technology, a Bluetooth (BT) technology, and other technologies.

In example embodiments, the device <NUM> may be implemented with one or at least two application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, micro-controllers, microprocessors, or other electronic components, for performing the above described methods.

In example embodiments, there is also provided a non-transitory computer readable storage medium including instructions, such as the memory <NUM> including instructions. The above instructions are executable by the processor <NUM> in the device <NUM>, for performing the above-described methods. For example, the non-transitory computer-readable storage medium may be a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disc, an optical data storage device, and the like.

A non-transitory computer-readable storage medium having stored therein instructions that, when executed by a processor of the device <NUM> described above, causes the device <NUM> to perform a method for obtaining a movement track , the method includes:.

In an embodiment, predicting the movement track of the preset person according to the current geographic location and the motion state of the preset person corresponding to the preset person information includes:.

Activating the target camera device along the movement track includes:.

In an embodiment, the method further includes:
activating other camera devices along the movement track, from which the distance to the current geographic location is greater than the preset distance, if the preset person is not captured after the target camera device is activated.

Before the target camera device from which the distance to the current geographic location is less than or equal to a preset distance is determined from the camera devices, the method further includes:.

Determining, from the camera devices, the target camera device from which the distance to the current geographic location is less than or equal to a preset distance includes:
determining, from the camera devices, the target camera device from which the distance to the current geographic location is less than or equal to the preset distance and whose direction corresponds to the current moving direction.

In an embodiment, the preset person information includes at least one of preset image information, a preset action, a preset gait and a preset expression.

Claim 1:
A method for obtaining a movement track, comprising:
obtaining (S101) target image information captured by a current camera device;
detecting (S102) whether a preset person is comprised within the target image information according to information related to the preset person;
obtaining (S103) a current geographic location of the current camera device, and if the preset person is comprised within the target image information:
predicting (S104) the movement track of the preset person according to the current geographic location of the current camera device and a motion state, the motion state comprising at least one of a current motion mode and a historical motion parameter of the preset person;
predicting (S501) a current motion parameter of the preset person according to the motion state, wherein the current motion parameter comprises a current moving rate and a current moving direction, wherein different motion states correspond to different motion parameters;
determining (S502) a distance according to the current motion parameter and the current geographic location, such that there are a suitable number of camera devices within the determined distance of the current camera device according to the current motion parameter and the current geographic location to capture the preset person and obtain the latest movement track of the preset person in time; wherein the numbers of the camera devices in the same distance are different depending on different geographic locations;
obtaining (B <NUM>) camera devices along the movement track;
determining (B2), from the camera devices obtained, a target camera device along the movement track so as to capture the preset person with the smallest number of camera devices, wherein the distance of the target camera device to the current geographic location is less than or equal to the determined distance, and whose direction corresponds to the current moving direction; and
activating (B3) the target camera device to capture the preset person, and updating the movement track when the preset person is captured.