JP2009229586A - Autofocus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To automatically track a desired AF target and perform an AF control correspondingly when the AF target disappears from a shooting range or appears in the shooting range. <P>SOLUTION: The autofocus system is equipped with a tracking mode switching means for switching a tracking mode in which an autofocus adjustment is disabled when it is detected that a selected tracking target disappears from an image range in the course of tracking the tracking target, and a tracking mode in which another registration pattern is tracked when it is detected that the selected tracking target disappears from the image range in the course of tracking the tracking target and if another registration pattern exists in the image area as well as the tracking target. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an autofocus system, and in particular, to focus while tracking a desired object (person) by automatically moving a position (range) targeted for autofocus (AF) within a shooting range of a camera. It can be related to autofocus system.

  Conventionally, when shooting a scene where the subject moves rapidly, such as soccer, figure skating, or horse racing, for example, with a TV camera, the auto focus (AF) area automatically follows the subject's movement to focus on the subject. Tracking systems are known (see, for example, Patent Document 1).

  In an imaging system that converts an image of a subject into an electrical signal (image signal) by an imaging device (CCD or the like) like a television camera, a contrast method is generally employed as an autofocus (AF) method. The contrast method is a method of automatically focusing to the best focus state by detecting the contrast of the subject image from the image signal captured by the image sensor and controlling the focus of the photographic lens so that the contrast becomes the highest. is there.

  In AF such as a contrast method, the entire subject within the shooting range of the camera is not targeted for AF, but only the subject within a part of the shooting range is often targeted. In contrast-based AF, an image signal in a range targeted for AF is extracted from image signals captured by the entire imaging area of the image sensor, and focus is performed so that the contrast of the image signal in the extracted range is the highest. By controlling this, the target of AF is limited to only a certain range of subjects. In this specification, the range of the subject to be AF in the shooting range of the camera or the image range of the subject to be AF in the shot image of the camera is referred to as an AF area, and the outline of the AF area is shown. The frame is called an AF frame.

In a lens system for broadcasting, for example, a cameraman performs pan / tilt (P / T) and zoom operations to fit a fast-moving subject, such as figure skates, on the screen. Is very difficult. In such a case, the AF area automatic tracking system as described above is effective.
JP 2006-267221 A

  However, in the AF area automatic tracking system as described above, for example, tracking can be performed when the subject is moving at least within the shooting range, but the subject protrudes from the shooting range and disappears from the screen (frame). If the subject is tracked again, and the subject enters the shooting range again (frames in), the subject cannot be recognized by simple pattern recognition. There is a problem that tracking may not be performed again.

  Also, for example, when shooting a soccer game, if there are multiple moving subjects within the shooting range, simple pattern recognition will recognize a specific subject and keep track of that subject. There is a problem that the tracking target may change and the image of the subject that should be tracked may be blurred.

  In recent years, the face authentication technology installed in digital cameras is effective for extracting people from the shooting range, but it does not recognize a specific person, and there are multiple people in the frame. In this case, there is a problem that if a face is simply an AF frame, a specific person cannot be recognized, so that the target of AF may be switched to another person.

  The present invention has been made in view of such circumstances, and solves the above-described problem. When a person to be AF is out of frame or in frame from a shooting range, a desired AF is correspondingly performed. An object of the present invention is to provide an autofocus system capable of automatically tracking an object and performing AF control.

  In order to achieve the above object, the invention according to claim 1 is directed to an imaging unit that captures a subject image formed by an optical system, and a predetermined AF area among the captured images captured by the imaging unit. Auto focus means for adjusting the focus of the optical system so that the subject is in focus, tracking means for moving the AF area in accordance with movement of the subject within the image range imaged by the imaging means, and the subject A pattern registration unit for registering a subject to be tracked, a tracking target detection unit for detecting a registered pattern registered in the pattern registration unit from subjects within an image range captured by the imaging unit, Tracking target selection means for selecting a target to be tracked among registered patterns registered in the pattern registration means, and further, the tracking target A tracking mode that turns off the autofocus adjustment of the autofocus unit when the tracking target detection unit detects that the tracking target is out of frame from the image range while tracking the tracking target selected by the selection unit. And while tracking the tracking target selected by the tracking target selection means, the tracking target detection means detects that the tracking target is out of frame from the image range, and the tracking target is within the image range. In addition, there is provided an autofocus system comprising tracking mode switching means for switching between tracking modes for tracking the other registered patterns when other registered patterns exist.

  As a result, appropriate automatic tracking control corresponding to the scene becomes possible.

  According to a second aspect of the present invention, in the tracking mode in which the autofocus adjustment is turned off, the autofocus off is maintained when the registered pattern enters the frame during the autofocus off.

  According to a third aspect of the present invention, in the tracking mode in which the autofocus adjustment is turned off, tracking of the registered pattern is started when the registered pattern is framed in during autofocus off.

  According to a fourth aspect of the present invention, in the tracking mode for turning off the autofocus adjustment, a tracking mode for maintaining the autofocus off when the registered pattern enters the frame during the autofocus off, and the autofocus off. A tracking mode switching means for switching between a tracking mode in which tracking of the registered pattern is started when a registered pattern is framed is provided.

  As a result, finer tracking control according to the shooting situation becomes possible.

  Further, as described in claim 5, in the tracking mode for tracking the other registered pattern, the tracking of the other registered pattern is continued when the tracking target is framed in again while tracking the other registered pattern. It is characterized by doing.

  Further, as described in claim 6, in the tracking mode for tracking the other registered pattern, the tracking of the other registered pattern is stopped when the tracking target is framed in again while tracking the other registered pattern. The tracking of the tracking target is resumed.

  Furthermore, as shown in claim 7, in the tracking mode for tracking the other registered pattern, the tracking of the other registered pattern is performed when the tracking target is framed in again while tracking the other registered pattern. A tracking mode in which tracking of the other registered pattern is stopped and tracking of the tracking target is resumed when the tracking target is framed in again while tracking the other registered pattern. A tracking mode switching means for switching is provided.

  These also enable finer tracking control according to the shooting situation.

  As described above, according to the present invention, when a person to be AF is out of frame or in from a shooting range, a desired AF object is automatically tracked and AF control is performed accordingly. Thus, appropriate automatic tracking control corresponding to the scene becomes possible.

  Hereinafter, an autofocus system according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing the overall configuration of an imaging system to which an autofocus system according to the present invention is applied. The image pickup system shown in FIG. 1 is an image pickup system used for shooting with a broadcast television camera, for example. In FIG. A lens device 12 having a system), a tracking device 16 including an operation unit 14, and the like are shown.

  The camera head 10 is equipped with an image sensor (for example, a CCD), a required signal processing circuit, and the like, and an image formed by the photographing lens of the lens device 12 is photoelectrically converted by the image sensor and then subjected to signal processing. Necessary signal processing is performed by the circuit. A video signal in a predetermined format generated by the signal processing circuit is output from the video signal output terminal of the camera head 10 to an external device. Further, a viewfinder (monitor) 18 for displaying an image captured by the camera head 10 and being used for composition confirmation or the like is installed in the tracking device 16. A video signal from the camera head 10 is given to the viewfinder 18, and a real-time image (video) captured by the camera head 10 is displayed on the screen of the viewfinder 18. Also, information such as an AF frame indicating the range of the AF area that is the target of autofocus (AF) can be displayed on the screen of the viewfinder 18.

  The lens device 12 includes a photographing lens (optical system) (not shown) attached to the lens mount of the camera head 10, and an object is imaged on the imaging surface of the imaging element of the camera head 10 by the photographing lens. The photographing lens is provided with movable parts for adjusting photographing conditions such as a focus lens group, a zoom lens group, and a diaphragm as its constituent parts. These movable parts are electrically driven by a motor (servo mechanism) (not shown). It is designed to be driven. For example, the focus lens group and zoom lens group move in the optical axis direction, and the focus (subject distance) adjustment is performed by moving the focus lens group, and the focal length (zoom magnification) adjustment is performed by moving the zoom lens group. Is done. In the system relating to autofocus as in the present embodiment, it is sufficient that at least the focus lens group can be driven electrically, and other movable parts may be driven only manually. Further, when the predetermined movable part is electrically driven in accordance with the operation of the operator, it is based on a control signal output in accordance with the operation of the operator from an operation unit (not shown) (such as an operation unit of a controller connected to the lens device 12). Thus, the operation of the movable part is controlled, but details are omitted.

  As shown in the figure, the lens device 12 is equipped with a lens CPU 20 that performs overall control of the lens device 12, an AF processing unit 22 that executes autofocus (AF) processing, an AF imaging circuit 24, and the like. Yes. The AF image pickup circuit 24 is disposed in the lens device 12 to acquire a video signal for AF processing, and outputs an image pickup device (CCD or the like) or an output signal of the image pickup device as a video signal of a predetermined format. Etc. The image pickup element of the AF image pickup circuit 24 is referred to as an AF image pickup element. The video signal output from the AF imaging circuit 24 is a luminance signal. On the imaging surface of the AF imaging element, subject light branched from the subject light incident on the imaging element of the camera head 10 is imaged by a half mirror or the like disposed on the optical path of the photographing lens. The shooting range and subject distance (distance of the subject in focus) with respect to the imaging area of the AF imaging element are configured to match the shooting range and subject distance with respect to the imaging area of the imaging element of the camera head 10 and are used for AF. The subject image captured by the image sensor matches the subject image captured by the image sensor of the camera head 10. Note that it is not necessary for the shooting ranges of the two to be completely the same. For example, the shooting range of the AF imaging device may be a larger range including the shooting range of the imaging device of the camera head 10.

  The AF processing unit 22 acquires a video signal from the AF imaging circuit 24, and calculates a focus evaluation value indicating the level of contrast of the subject image based on the video signal. For example, after extracting a high-frequency component signal of a video signal obtained from an AF image sensor with a high-pass filter, a signal in a range corresponding to the AF area targeted for AF is extracted from the high-frequency component signal. Accumulate one screen (one frame) at a time. The integrated value obtained for each screen in this manner indicates the level of contrast of the subject image, and is given to the lens CPU 20 as a focus evaluation value. The AF area range is designated by the lens CPU 20 as will be described later.

  As will be described in detail later, the lens CPU 20 acquires AF frame information (AF frame information) indicating the range (contour) of the AF area from the operation unit 14, and determines the range within the AF frame specified by the AF frame information. The AF processing unit 22 is designated as the AF area. Then, a focus evaluation value obtained from an image (video signal) in the AF area is acquired from the AF processing unit 22. In this way, every time a video signal for one screen is acquired from the AF imaging circuit 24 (each time the focus evaluation value is obtained by the AF processing unit 22), the focus evaluation value is acquired from the AF processing unit 22, and The focus lens group is controlled so that the acquired focus evaluation value is maximum (maximum), that is, the contrast of the subject image in the AF area is maximum. For example, a hill-climbing method is generally known as a control method for a focus lens group based on a focus evaluation value, and the focus evaluation value starts to decrease by moving the focus lens group in a direction in which the focus evaluation value increases. Is detected, the focus lens group is set at that position. Thereby, the subject in the AF frame is automatically focused.

  The tracking device 16 is a device that automatically changes the position of the AF frame by moving the AF point in accordance with the movement of the target while tracking the target specified by the operator on the screen. An image processing unit 26, an image input unit 28, a tracking processing unit 30, a pattern data storage unit 32, a frame information generation unit 34, a video composition unit 36, and the like are included.

  When the operator does not change the AF frame, the tracking device 16 automatically changes the AF frame. Further, when the operator performs an operation of changing the AF frame, the operation is prioritized over the tracking device 16 and the AF frame is changed according to the operation of the operator.

  The operation unit 14 includes a trackball 14a that designates the movement direction and the movement amount of the AF frame as an operation member for the operator to designate the setting contents of the AF frame such as the position, shape, and size of the AF frame. Is provided. The operation unit 14 is also provided with a push button switch 14b as an operation member for registering and selecting which subject in the screen is a tracking target to be tracked by AF. As illustrated in FIG. 1, a plurality of switches 14b may be provided, and a plurality of tracking targets to be tracked by AF may be registered by registering tracking targets in association with the respective switches 14b. The tracking target pattern data to be registered (registered pattern) is stored in a database of the pattern data storage unit 32 described later.

  FIG. 2 shows an example of the AF frame. As shown in FIG. 2, the AF frame indicates the outline of the AF area indicating the AF target range with respect to the shooting range or the shot image by the imaging element of the camera head 10.

  When the operation member is operated by the operator, the operation unit 14 sets and changes setting contents such as the position of the AF frame according to the operation. In this embodiment, it is assumed that the shape of the AF frame is limited to a rectangle. Also, the setting contents such as the position and size of the AF frame by the operation member of the operation unit 14 are changed by an amount corresponding to the subsequent operation amount of the operation member based on the setting contents of the AF frame before the operation. This is done by changing the settings. For example, the position of the AF frame is displaced in the vertical and horizontal directions by a direction and a movement amount corresponding to the rotation direction and the rotation amount of the trackball 14a. Also, if the point that determines the position of the AF frame on the shooting range (captured image) (in this embodiment, the center position of the rectangular AF frame) is called an AF point, the position of the AF frame is the position of the AF point. It depends on the setting.

  On the other hand, while the operating member is not operated and the operator is not instructed to change the setting contents of the AF frame, the AF frame is set and changed in the tracking processing unit 30 described later. The operation unit 14 transmits AF frame information indicating the setting contents of the AF frame set and changed by the operation of the operator to the lens CPU 20 in accordance with a request from the lens CPU 20 and to the tracking processing unit 30. . In addition, AF frame information indicating the setting contents of the AF frame set or changed in the tracking processing unit 30 is transmitted to the lens CPU 20 via the operation unit 14. As a result, the AF target range for performing the tracking process in the tracking processing unit 30 is set as the range of the AF frame.

  The image input unit 28 acquires the video signal (luminance signal) obtained by the above-described AF imaging circuit 24 via the AF processing unit 22, and the image in the range specified by the image processing unit 26 in the shooting range ( Image data) is provided to the image processing unit 26.

  The image processing unit 26 performs predetermined image processing on the image data acquired from the image input unit 28 and sends the image data to the tracking processing unit 30.

  The tracking processing unit 30 uses the pattern data (registered pattern) stored in the pattern data storage unit 32 in the AF area determined by the AF frame set above from the sent image data for the purpose of security. A person's face (object) is identified and recognized by a known face (object) authentication technique, a specific person (object) in the AF area to be tracked is tracked, AF is performed, and the movement of the object is followed. To move the AF point.

  The pattern data storage unit 32 registers and stores pattern data necessary for recognizing a specific person (object) in the AF area as a tracking target to be tracked by AF. At this time, by registering one pattern data (registration pattern) corresponding to each one of the plurality of switches 14b, a plurality (for a plurality of persons) of pattern data (registration patterns) to be tracked are registered. be able to.

  The pattern data may be registered in advance by the operator associating the pattern data with each switch 14b in advance, or the tracking processing unit 30 may record the pattern data of the person in the screen during shooting. The switch 14b may be automatically assigned and registered. In the example shown in FIG. 1, since there are five switches 14b, up to five people can be registered, but the number of people that can be registered is not particularly limited.

  When pattern data indicating a tracking target is registered in the pattern data storage unit 32, when the operator presses one of the switches 14b, the tracking target of the pattern data corresponding to the pressed switch 14b is selected. When a tracking target is selected, it is always searched whether the selected tracking target exists on the screen during shooting, and when the selected tracking target is found, the subject that is the tracking target AF is started simultaneously with tracking. Although not shown, the operation unit 14 is further provided with an automatic tracking switch for instructing the start and end of automatic tracking.

  In addition, when a plurality of tracking targets are registered in the pattern data storage unit 32, when there are a plurality of registered patterns in the screen, the registered pattern is out of the screen, or the registered pattern is in the screen. In this case, each of the plurality of registered patterns may be prioritized so that the registered pattern to be tracked can be automatically selected. At this time, the order (switch number order) registered in association with each switch 14b may be used as the priority order.

  The frame information generation unit 34 receives AF frame information from the tracking processing unit 30 and generates AF frame data for display in order to display the AF frame on the image displayed on the display screen of the viewfinder 18. It is.

  The video synthesis unit 36 synthesizes the image data (video signal) sent from the camera head 10 and the frame information data generated for display sent from the frame information generation unit 34 to display them on the viewfinder 18. An image is generated and sent to the viewfinder 18.

  The viewfinder 18 displays an image displayed with AF frames superimposed at corresponding positions on the screen. Furthermore, a frame may be displayed on the face of the person of the registered pattern that is the tracking target in the AF frame. The switch 14b may also serve as a switch for turning on / off the display of the face frame. Further, as shown in FIG. 1, for example, a name such as “FUJI # 1” is displayed for specifying the tracking target for the face frame, and AF driving is being performed at the bottom of the screen. A display or the like may be displayed.

  Next, the basic operation of the autofocus system of this embodiment will be described.

  FIG. 3 is a flowchart showing the basic operation of the autofocus system of the present embodiment.

  In the embodiment shown in FIG. 3, one (one) subject is set as a tracking target, and a registered pattern is detected from a captured image to automatically track.

  First, initial setting is performed in step S100 of FIG.

  Next, in step S102, it is determined whether or not automatic tracking is performed. This is determined by ON / OFF of the tracking switch that instructs the start and end of automatic tracking of the target in the AF area. The tracking switch is installed in the operation unit 14, for example, although not shown.

  If it is determined in step S102 that automatic tracking is OFF, the tracking target is registered in the next step S104, and it is determined whether or not the pattern data (registered pattern) is stored. This is determined by ON / OFF of the switch 14b described above.

  If it is determined in step S104 that the tracking target is registered and the registered pattern is not stored, in the next step S106, the operator manually sets the AF area.

  When the AF area is manually set, in the next step S108, it is determined whether AF (autofocus) is ON / OFF. This is also determined by ON / OFF of an AF switch that instructs the start and end of AF (not shown).

  When AF is ON, in the next step S110, normal AF processing is performed, and the focus lens is automatically controlled so that the subject in the AF area set above is in focus.

  On the other hand, if it is determined in step S108 that AF is OFF, in step S112, the operator manually performs focus control.

  If it is determined in step S104 that the tracking target is registered and the registered pattern is stored, the registered pattern is registered and stored in the following procedure. That is, first, in step S <b> 114, the image processing unit 26 of the tracking device 16 acquires an image via the image input unit 28.

  Next, in step S116, a pattern is sampled from the image acquired by the image processing unit 26. The face of the subject person is detected from the image, and pattern data necessary for recognizing a specific individual as a tracking target is extracted.

  In step S118, the pattern data extracted above is registered (stored) in the database of the pattern data storage unit 32 via the tracking processing unit 30.

  In step S120, the tracking processing unit 30 tracks the tracking target indicated by the registered pattern just registered and starts AF. The operator confirms the tracking target with the viewfinder 18.

  The operator determines whether or not to end the sampling in step S122 depending on whether or not the target that is now being automatically tracked is acceptable.

  If it is determined in step S122 that the sampling is to be terminated, in step S124, the switch 14b for instructing registration (storage) of the registration pattern is turned OFF.

  When registration (storage) of the registration pattern is completed in this way, in the next step S126, the tracking processing unit 30 sets an internal switch for forcibly starting tracking of the tracking target just registered with respect to the target of the AF area. Turn on and start automatic tracking process.

  Next, in step S128, a name (name, No., etc.) for the tracking target is registered. When the tracking target name is registered, a name (name, No., etc.) indicating the tracking target such as “FUJI # 1” is displayed on the display screen of the viewfinder 18 as shown in FIG. Can do. This name registration can be performed using, for example, an alphanumeric key (not shown) provided in the operation unit 14. After registering the name, the process proceeds to step S130, and an automatic tracking process is executed.

  On the other hand, in step S122, if the pattern sampled above and registered in the database is different from the target to be tracked by the operator, the sampling is still finished because the sampling needs to be repeated. If it is determined not to proceed, the process proceeds to step S108 and then returns to step S102.

  Also. If it is determined in step S102 that automatic tracking is ON, the process proceeds to step S130, and the following automatic tracking process is executed.

  First, in step S <b> 130, the image processing unit 26 acquires an image in the AF area currently being photographed from the lens device 12 via the image input unit 28. The image processing unit 26 detects a face from the acquired image and acquires data necessary for comparison with the registered pattern.

  Although the AF area is currently being automatically tracked, it is determined in step S132 whether the target of the AF area in the captured image has already been found as a registered pattern.

  As a result, if it is already found as a registered pattern and the tracking target corresponding to the pattern is automatically tracked, the process proceeds to step S134, and it is determined whether or not the name of the tracking target is displayed. Whether or not to display the name is determined by whether the switch 14b corresponding to the registered pattern is display ON or display OFF. In the present embodiment, the switch 14b serves as both a switch for instructing pattern registration and a switch for instructing display of a name, but of course, these may be separate switches.

  If the name display is ON in step S134, it is determined in next step S136 whether or not the name for the tracking target is registered.

  If the name is registered, the registered name of the tracking target, for example, “FUJI # 1” is displayed in step S138, and if the name is not registered, for example, “ #? ”Is displayed. Thus, the operator can easily confirm whether or not each subject displayed on the screen of the viewfinder 18 is registered.

  In step S142, automatic tracking is continued for the tracking target.

  If no registered pattern to be tracked is found yet in step S132, the tracking processing unit 30 is the same as the registered pattern sampled above and registered in the database of the pattern data storage unit 32 in step S144. Is searched from the image of the AF area received from the image processing unit 26.

  In step S146, when the same pattern as the registered pattern is found, the process proceeds to step S134, and the above-described processing when the registered pattern has already been found is executed. If the same pattern as the registered pattern is not found, it is determined in step S148 whether collation with all registered pattern data has been completed. If collation with all data has not been completed yet, the process returns to step S144. On the other hand, when collation with all data is completed, a pattern search error is displayed in step S150, and in step S152, automatic tracking for the AF area target is forcibly turned off, and the process proceeds to step S108. .

  Next, another configuration example of the imaging system to which the autofocus system according to the present invention is applied will be described.

  FIG. 4 is a block diagram showing another configuration example of the imaging system to which the autofocus system according to the present invention is applied.

  The imaging system shown in FIG. 4 has substantially the same configuration as the imaging system shown in FIG. 1 described above, and includes a camera head 110, a lens device 112, a tracking device 116 including an operation unit 114, a viewfinder 118, and the like. .

  The camera head 110 is mounted with an image sensor such as a CCD, a required signal processing circuit, and the like. The lens device 112 includes a photographic lens (not shown) attached to the lens mount of the camera head 110, and a subject is imaged on the imaging surface of the imaging element of the camera head 110 by the photographic lens. The lens device 112 includes a lens CPU 120, an AF processing unit 122, an AF imaging circuit 124, and the like.

  The tracking device 116 includes an operation unit 114, an image processing unit 126, an image input unit 128, a tracking processing unit 130, a pattern data storage unit 132, a frame information generation unit 134, a video composition unit 136, and the like.

  In the example illustrated in FIG. 4, only the configuration of the operation unit 114 is different from that illustrated in FIG. 1, and the configuration other than the operation unit 114 is the same as that in FIG. 1 described above. Therefore, detailed description of the detailed configuration of each unit other than the operation unit 114 will be omitted.

  The operation unit 114 in FIG. 4 includes a cross key 114a instead of the trackball 14a as an operation member for manually specifying the movement direction and movement amount of the AF frame, and a switch 114b for registering and selecting a tracking target. A display panel 114c for confirmation when the name of the tracking target is registered, an indicator 114d indicating the zoom (Z) and focus (F) states, a slide switch 114e for selecting a tracking mode to be described later, and the like. .

  The switch 114b is for registering and selecting a tracking target in the same manner as the switch 14b of the operation unit 14 in FIG. The tracking target can be registered in association with each switch 114b. In addition, a name can be registered for each tracking target in order to identify each tracking target. The name registration is performed, for example, by inputting alphanumeric characters using a key (not shown). The input name is displayed on the confirmation display panel 114c.

  In the example shown in FIG. 4, a tracking target named “XXXX # 1” is registered in 1 of the switch 114b, and a tracking target named “YYYY # 2” is registered in 2 of the switch 114b.

  The indicator 114d is provided with one set of Z (zoom) and F (focus) for each switch 114b, and displays the zoom and focus states, respectively.

  The slide switch 114e is for switching the tracking mode (tracking mode switching means). The tracking mode will be described later in detail. In FIG. 4, by switching the setting position of the slide switch 114e, there are three types of modes: a zoom and focus preset mode (Z + F mode), a face recognition automatic tracking mode (OBJ mode), and a combined mode (Z + F + OBJ mode). However, the mode setting is not limited to this, and as described later, it is possible to set more modes such as modes M1 to M4 and switch them.

  FIG. 5 shows an example of an image displayed on the screen of the viewfinder 118. FIG. 5 shows an image when the video of a soccer game is automatically tracked, and a face frame is displayed for each recognized face in the screen.

  In the case of automatic tracking, when a registered face pattern is automatically recognized in the frame, a name (name, No., etc.) is registered for the tracking target, and the display is ON. The name is displayed near the face frame.

  In the case of FIG. 5, there are two registered patterns in the frame, names are also registered for the respective patterns, and “XXXX # 1” and “YYYY # 2” are assigned to the face frames, respectively. The name (name and No.) is displayed. Also, no photographer-like person at the back of the screen is registered, and the name is displayed as “#?” For the face frame so that the operator knows that these persons are not registered. It has become.

  In some cases, displaying the name in this way makes it difficult to see the screen, so the name may not be displayed (OFF).

  Furthermore, when there are a plurality of registered patterns in the frame, if the face frame is displayed for all of them, it is difficult to understand who is tracking, so the face frame of the tracking target (AF target) You may make it display by changing a color.

  As described above, in FIG. 5, there are a plurality (two persons) of registered patterns in a frame, and it is possible to select which one of them is a face pattern to be tracked by AF.

  There are various methods for selecting an AF area as a tracking target to be tracked by applying this AF. For example, the operator may select the AF area by pressing the switch 114b of the operation unit 114, or prioritize the registered patterns in priority order. When there are a plurality of registered patterns on the screen, the registered pattern with the highest priority among them may be automatically selected. Alternatively, it may be automatically selected according to the registration order (registration No. order) when registering corresponding to the switch 114b. The registration order and priority are similar, but not necessarily the same. After registration, the priority order can be set differently from the registration order, and the priority order can be changed.

  A tracking target (AF area) to be tracked by AF is determined, and automatic tracking is started on the screen, and at the same time, AF is automatically started for the tracking target. When automatic tracking is being executed, the tracking target may be out of frame, but various situations can be considered.

  For example, when the tracking target is out of frame, there are cases where no other registered pattern exists in the screen, and there are cases where another registration target still exists in the screen even if the tracking target is out of frame.

  Furthermore, when there is no other registered pattern on the screen at this time, the registered pattern that has been tracked until now comes in again, and other registered patterns that are not the target of tracking come in. There is a case. In addition, when another tracking target exists in the screen when the tracking target is out of frame, the target that has been tracked so far may be framed in again.

  In these cases, various tracking control methods (tracking modes) such as how to select a tracking target and how to perform automatic tracking can be considered. In the following, this will be described with different cases.

  FIG. 6 shows a registration pattern in which, when the registered pattern A is automatically tracked as a tracking target, when the currently tracked pattern A is once out of the frame, the various patterns thereafter appear mainly on the screen. It is the flowchart divided into cases when paying attention to.

  As shown in step S201 of FIG. 6, it is assumed that the registered pattern (tracking pattern) A currently being tracked is out of the frame.

  At this time, there are a case where no registered pattern exists in the screen and a case where a registered pattern other than the pattern A exists.

  Therefore, first, as shown in step S202, consider a case where there is no other registered pattern in the screen after the pattern A is out of frame. In this case, since there is no longer any pattern to be tracked in the screen, AF (autofocus) is turned off as shown in step S203. After that, while the registered pattern does not exist in the screen, the AF is kept off as it is.

  After that, it is assumed that the registered pattern is framed in the screen. At this time, as shown in step S204, when the pattern A that has been tracked until now comes in again, and as shown in step S205, other registered patterns B other than the pattern A come in frame. There are cases.

  In the case where the pattern A is framed in again in step S204, the pattern A that has been tracked up until now appears again in the screen, so that the tracking of the pattern A is started again as shown in step S206. Once the frame is out, the pattern A is no longer tracked, and the AF may be kept OFF as shown in step S207.

  Also, as shown in step S205, when the pattern A that was first tracked out of the frame and there is no registered pattern to be tracked in the screen, another registered pattern B came in the frame. In this case, since the pattern A has been tracked so far, it does not matter if another registered pattern B comes into the frame, so as shown in step S207, AF is still left OFF. Then, since the pattern A has disappeared and the registered pattern B has entered instead, the registered pattern B may be tracked for the time being, as shown in step S208.

  Here, the pattern A is tracked again in step S206 only when the pattern A is prioritized as a tracking target, and is not a tracking target even if another registered pattern is framed in. The other registered pattern B in step S208 is tracked after the pattern A is out of the frame, so that anybody can enter the registered pattern anyway.

  In step S205, after the pattern A that was first tracked out of the frame and the registered pattern does not exist in the screen, only one registered pattern B is next framed in. Of course, there may be a case where a plurality of registered patterns other than A frame in at the same time and a plurality of registered patterns exist in the screen. At that time, in step S208, any one of the plurality of registered patterns is selected as a tracking target. The selection method will be described later.

  Next, as shown in step S209, consider a case where there is a registered pattern other than the pattern A in the screen even after the pattern A is out of frame.

  In this case, since there is no tracking pattern A, AF is turned off as shown in step S210 and other registered pattern B existing in the screen is tracked as shown in step S211. You could think so.

  In this step S211, when tracking of another registered pattern B is started, if the registered pattern is only the pattern B in the screen, the pattern B should be tracked naturally, but there are a plurality of registered patterns in the screen. In some cases, one tracking pattern must be determined by some method. A method of selecting one registered pattern as a tracking target (tracking pattern) from among a plurality of registered patterns will be described later.

  When AF is turned off in step S210, as shown in step S212, when pattern A comes into the screen again in the screen, the situation is the same as in step S204 described above.

  That is, in this case, as shown in step S213, even if the pattern A enters the frame again, AF is kept OFF, or the tracking of the pattern A is started again as shown in step S214. Can be considered.

  On the other hand, when the other registered pattern B is tracked in step S211, as shown in step S215, if the pattern A comes in the screen again, as shown in step S214, Switch the tracking target from the currently tracked pattern B to the originally tracked pattern A and start tracking the pattern A again, or, as shown in step S216, track the currently tracked pattern B. There are two ways to continue.

  After all, the automatic tracking control method shown in FIG. 6 can be summarized as follows.

  The flow of steps S201, S202, S203, S204, and S206 and steps S201, S209, S210, S212, and S214 has pattern A as the main tracking target, and if pattern A is out of frame, there is another registered pattern in the screen. The tracking of the pattern A is always prioritized so that the AF is turned off and the tracking of the pattern A is started again when the pattern A enters the frame again.

  Also, the flow of steps S201 → S202 → S203 → S205 → S208 is to track another registered pattern B when it enters the frame after the pattern A has gone out of the frame.

  In addition, the flow of steps S201 → S202 → S203 → S204 (S205) → S207 and steps S201 → S209 → S210 → S212 → S213 is performed after the pattern A once out of the frame even if the pattern A is tracked until then. Even if the pattern A or another registered pattern enters the frame, the AF remains off all the time.

  Thus, the above tracking control flow gives priority to the tracking of the pattern A.

  On the other hand, the flow of steps S201 → S209 → S211 follows the pattern A, but if the pattern A is out of frame, if there is another registered pattern in the screen, it will be tracked for the time being. It is to try. Further, in this case, as in the flow from step S215 to S214, the tracking of other registered patterns is only temporary, and if the pattern A enters the frame again, the tracking target is returned to the pattern A, and steps S215 to S216. There are cases where the tracking target is completely switched to another registered pattern as shown in the flow and the tracking of another registered pattern is continued as it is even if the pattern A is framed again.

  Then, the tracking control described above with reference to FIG. 6 can be simply expressed as shown in FIG.

  That is, when tracking the registered pattern A as a tracking target and the tracking pattern A is out of frame, it is either “turn off AF” or “track other registered pattern B”. If the registered pattern enters the frame when "AF is turned off", whether the previous state ("turn off AF") is maintained or tracking of the registered pattern that has been framed in is started. If the registered pattern A enters the frame when “tracking another registered pattern B” is selected, the previous state (“track other registered pattern B”) is maintained. Or the tracking of the frame-in pattern A is resumed.

  As described above, when the pattern A is out of frame, the mode M1 in which AF remains off even if the registered pattern is subsequently framed in. If any registered pattern is in frame after the pattern A is out of frame, the registered pattern is tracked. Mode M2 in which the tracking target is started (especially, the pattern A that has been tracked up to that time is prioritized), and when the pattern A is out of the frame, the tracking target is switched anyway, and another registered pattern B is tracked A mode M4 in which tracking of the pattern A is resumed once the pattern A enters the frame again even if tracking of the other registered pattern B is once performed can be considered.

  The above is the most basic tracking control method in the present embodiment. Actually, there may be various complicated cases, but tracking control is performed based on the above basic case.

  In practice, the system may have all the above modes, or only some of them. When a plurality of modes are provided, each mode can be switched, and it is preferable that the operator can perform various tracking processes by switching each mode according to, for example, a scene each time.

  For example, when the tracking pattern A is out of frame, there are two modes: a mode M1 that keeps AF OFF even if the registered pattern is in frame, and a mode M2 that tracks the registered pattern when the registered pattern is in frame. Therefore, the system configuration may be such that these modes are switched.

  Alternatively, after the tracking pattern A is out of frame, another registered pattern B is tracked, and even if the pattern A enters the frame again, the mode M3 in which the pattern B remains tracked, and the pattern A is framed again. If it is turned on, the mode M4 for tracking the pattern A again may be switched.

  Alternatively, the combination of the mode M1 and the mode M2 and the combination of the mode M3 and the mode M4 may be switched.

  Next, as in the case of step S209 in FIG. 6, when there are a plurality of registered patterns in the screen, which registered pattern is selected as a tracking target from among them will be described.

  When there are a plurality of registered patterns in the screen, the method of selecting which registered pattern to select as the tracking target is selected according to the case where the operator selects and the order in which the registered patterns are registered. May automatically select, or the system may automatically select according to a priority set in advance between registered patterns.

  First, when registering a pattern, for example, during shooting, the subject in the screen is assigned to each of the switch 14b of the operation unit 14 in FIG. 1 or the switch 114b in FIG. 4 and automatically numbered and registered. It has come to be. According to this, it is possible to register as many patterns as the maximum number of switches. When the operator selects a registration pattern, if the operator presses, for example, the second switch of the switch 14b (or 114b), the registration pattern assigned to the second switch is selected. It is like that.

  In addition, the pattern may be registered manually by the operator as described above, with names registered, and with priorities assigned.

  The order of registration is performed in the order of arrangement of the switches 14b (or 114b). The order of registration and the priority order do not necessarily match. For example, when a pattern is registered by being automatically numbered and assigned to each switch as described above, the operator can give a priority order different from the order of the switches. .

  In the tracking control in FIG. 6 described above, for example, if the tracking pattern A is out of frame in step S210, the selection of the tracking target of the pattern A is canceled, the AF is turned off, and no other registered pattern is selected as the tracking target. Even if the pattern A enters the frame again, the AF remains off for a long time. Thereby, the mode M1 of FIG. 7 is implement | achieved.

  Similarly, when the tracking pattern A is out of frame in step S201 in FIG. 6 and AF is once turned off, the registered pattern is tracked anyway, and in particular, the pattern A is preferentially set as the tracking target. If it is selected, the registered pattern is always searched in the screen. Therefore, when the registered pattern is framed in, the registered pattern is detected and tracking of the registered pattern is started. At this time, the tracking of the pattern A is given priority. In this way, the mode M2 of FIG. 7 is realized.

  Also, for example, when it is set to always track the registered pattern with the highest priority, when the currently tracked pattern is out of frame, the priority of the pattern is changed to the lowest. Then, in step S211 in FIG. 6, when the pattern A that has been tracked is out of frame and the pattern B of the next priority is being tracked, even if the pattern A is framed in again in step S215. Since the priority order of the pattern A has already been lowered, the pattern A is not tracked in step S216, and the tracking of the pattern B is continued as it is. Thereby, the mode M3 in FIG. 7 is realized.

  Also, for example, when the pattern A that was first tracked during the tracking of the pattern B in step S215 in FIG. 6 enters the frame again, the priority order of the pattern A is set higher than the other registered patterns, and the screen If there are a plurality of registered patterns in the pattern, it is set to preferentially track a registered pattern having a higher priority. In step S214, tracking of the pattern A is started again instead of the pattern B. Thereby, the mode M4 in FIG. 7 is realized.

  Thus, by setting the priority for selecting the tracking target, the tracking target can be automatically changed. The mode switching is performed by the slide switch 114e of the operation unit 114. Alternatively, the above modes may be set or switched by manually selecting a tracking target via the operation unit 14 (114).

  The autofocus system of the present invention has been described in detail above. However, the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.

1 is a block diagram illustrating an overall configuration of an imaging system to which an autofocus system according to the present invention is applied. It is explanatory drawing which shows the example of AF frame. It is a flowchart which shows the basic operation | movement of the auto-focus system of this Embodiment. It is a block diagram which shows the other structural example of the imaging system to which the autofocus system which concerns on this invention is applied. It is explanatory drawing which shows the example of the image displayed on the screen of a viewfinder. It is a flowchart which shows the mode of the tracking control after the object in tracking is out of a frame. It is explanatory drawing which shows collectively the tracking control shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Camera head, 12 ... Lens apparatus, 14 ... Operation part, 14a ... Trackball, 14b ... Switch, 16 ... Tracking apparatus, 18 ... Viewfinder, 20 ... Lens CPU, 22 ... AF processing part, 24 ... Imaging for AF Circuit, 26 ... Image processing unit, 28 ... Image input unit, 30 ... Tracking processing unit, 32 ... Pattern data storage unit, 34 ... Frame information generation unit, 36 ... Video composition unit

Claims (7)

Imaging means for imaging a subject image formed by an optical system;
Auto focus means for adjusting the focus of the optical system so that a subject in a predetermined AF area out of the captured image captured by the imaging means is in focus;
Tracking means for moving the AF area in accordance with movement of a subject within an image range imaged by the imaging means;
Pattern registration means for registering a subject to be tracked among the subjects;
Tracking target detection means for detecting a registered pattern registered in the pattern registration means from within a subject within an image range imaged by the imaging means;
Tracking target selection means for selecting a target to be tracked among registered patterns registered in the pattern registration means, and
While tracking the tracking target selected by the tracking target selection unit, when the tracking target detection unit detects that the tracking target has been out of frame from the image range, the autofocus adjustment of the autofocus unit is turned off. Tracking mode to
While tracking the tracking target selected by the tracking target selecting means, when the tracking target detecting means detects that the tracking target is out of frame from the image range, the tracking target is not included in the image range. An autofocus system comprising tracking mode switching means for switching between a tracking mode for tracking the other registered pattern when another registered pattern exists.   2. The autofocus system according to claim 1, wherein in the tracking mode in which the autofocus adjustment is turned off, the autofocus off is maintained when a registered pattern enters the frame during autofocus off.   2. The autofocus system according to claim 1, wherein in the tracking mode in which the autofocus adjustment is turned off, tracking of the registered pattern is started when the registered pattern is framed in while autofocus is turned off.   In the tracking mode in which the autofocus adjustment is turned off, the tracking mode in which the autofocus off is maintained when the registered pattern is framed in while the autofocus is off, and the registered pattern is in frame when the autofocus is off. 2. The autofocus system according to claim 1, further comprising a tracking mode switching means for switching between a tracking mode for starting tracking of the registered pattern.   In the tracking mode for tracking the other registered pattern, the tracking of the other registered pattern is continued when the tracking target is framed in again while tracking the other registered pattern. 4. The autofocus system according to any one of 4.   In the tracking mode for tracking the other registered pattern, when the tracking target is framed in again while tracking the other registered pattern, the tracking of the other registered pattern is stopped and the tracking of the tracking target is resumed. The autofocus system according to any one of claims 1 to 4, wherein   In the tracking mode for tracking the other registered pattern, the tracking mode for continuing the tracking of the other registered pattern when the tracking target is framed in again while tracking the other registered pattern; Tracking mode switching means for switching between tracking mode for stopping tracking of the other registered pattern and resuming tracking of the tracking target when the tracking target is framed again during tracking of the registered pattern. The autofocus system according to any one of claims 1 to 4, wherein

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