JP2010085530A - Autofocus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera system having a face authentication function, which is easily focused on respective subjects successively even when there exist a plurality of subjects. <P>SOLUTION: The autofocus system includes: an imaging means for imaging the subject; an autofocus means for performing focus adjustment within a prescribed AF area out of a photographic image; a focus object registering means for preregistering the plurality of subjects to be set as a focus object together with information necessary for face authentication and order of setting the focus object during photography; a focus object designating means for designating the subject set as the focus object during photography out of the plurality of subjects to be set as focus objects registered in advance; and a face authentication means for submitting the subject which is being imaged and the subject set as the designated focus object to the face authentication. When it is decided that the subject which is being imaged is the same person as the subject set as the designated focus object by the face authentication, the focus adjustment is performed to the subject which is being imaged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an autofocus system, and more particularly to an autofocus system capable of performing face authentication and tracking while tracking a specific person within a shooting range of a camera in a camera system having a face authentication function.

  Conventionally, in an autofocus (AF) system that automatically adjusts the focus of a camera, the camera must be instructed where to focus. At this time, in a general camera or the like, the position to be focused is fixed at the center of the shooting range, and for example, the person in the center of the shooting range is focused.

  However, when shooting a moving subject, it is inconvenient if the focus position is fixed in this way. Therefore, for example, when shooting a scene where the subject moves rapidly, such as sports, with a TV camera or the like, an AF area automatic tracking system in which the autofocus area (AF area) follows the subject movement for the purpose of focusing on the subject. Is known (see, for example, Patent Document 1).

  In addition, an image representing a human face is detected from the captured image, and the face that is the subject is automatically focused, or the area representing the face in the detected image is enlarged. There is known a digital camera that automatically changes the zoom magnification (see, for example, Patent Document 2).

Recently, the performance of an embedded CPU has been improved, and a system for detecting and authenticating a person's face from the screen and focusing on the authenticated specific person has been introduced.
JP 2006-267221 A JP 2004-320286 A

  However, in the system for focusing on a specific person whose face has been authenticated, it is necessary to set the person to be focused on in advance in the system. There is a problem that inconvenience occurs when the focus is adjusted.

  The present invention has been made in view of such circumstances, and in a camera system having a face authentication function, an autofocus system that can easily focus on each subject one after another even if there are a plurality of subjects. The purpose is to provide.

  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, a plurality of subjects to be focused, information necessary for face authentication, and the order to be focused at the time of shooting, in advance Focus target registration means for registering, focus target specifying means for specifying a subject to be focused during shooting from among the plurality of previously registered subjects to be focused, the subject being imaged, and the designation Face recognition means for performing face authentication on the subject to be focused, and the subject being imaged is designated by the face authentication. If it is determined that the an object the same person serving as a focal object to provide an autofocus system and executes the focus adjustment by the automatic focusing means with respect to an object in the imaging.

  Thereby, in a camera system having a face authentication function, it is possible to easily focus on each subject one after another even if there are a plurality of subjects.

  According to a second aspect of the present invention, the focus target designating unit determines the order of the subject to be focused next in accordance with a change in the shooting scene, based on the order of the focus target at the time of the pre-registered shooting. By designating, a subject to be focused is designated during the photographing.

  Thus, based on the order registered in advance, the focus can be easily adjusted to the subject to be focused next in accordance with the change of the scene only by sequentially sending the order using, for example, a switch.

  According to a third aspect of the present invention, the focus target designating unit is a liquid crystal display screen having a touch panel function.

  Thereby, anyone can easily switch to the next focus target.

  According to a fourth aspect of the present invention, the focus target specifying unit has a voice recognition function, and specifies a subject to be focused by voice input.

  Thereby, even when both hands are closed, the focus target can be easily switched.

  As described above, according to the present invention, in a camera system having a face authentication function, it is possible to easily focus on each subject one after another even if there are a plurality of subjects.

  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. This imaging system is, for example, an imaging system used for shooting with a broadcast television camera.

  As shown in FIG. 1, the imaging system 1 of the present embodiment performs a TV camera 10 that captures a subject, a viewfinder 16 that displays the captured image, face authentication of the subject, and automatic AF tracking based on this. The image processing unit 18 and the operation unit 20 are included.

  The television camera 10 includes a camera body 12 composed of an HD camera compatible with a high-definition television [HD (High Definition) TV] system, and a lens device 14 having a photographing lens (optical system) attached to a lens mount of the camera body 12. It consists of. The camera body 12 is supported on a pan head 22 so as to be movable in a turning direction (pan) and a vertical tilt direction (tilt).

  The camera body 12 is equipped with an image sensor (for example, a CCD), a required signal processing circuit, and the like. An image formed by the photographing lens of the lens device 14 is subjected to signal conversion after being photoelectrically converted by the image sensor. Necessary signal processing is performed by the circuit and output as an HDTV video signal (HDTV signal) from the video signal output terminal of the camera body 12 to the outside.

  The lens device 14 includes a photographing lens (zoom lens) 24 that is attached to the lens mount of the camera body 12. The photographic lens 24 forms an image of the subject on the imaging surface of the imaging device of the camera body 12. Although not shown, the photographic lens 24 is provided with movable parts for adjusting photographing conditions such as a focus lens group, a zoom lens group, and a diaphragm as constituent parts thereof. Servo mechanism) is electrically 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 related to autofocus, 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 portion is electrically driven according to the operation of the operator, it is based on a control signal output according to the operation of the operator from an operation means (not shown) such as an operation means of a controller connected to the lens device 14. Thus, the operation of the movable part is controlled, but details are omitted.

  The lens device 14 includes an AF unit 26 and a lens CPU (not shown). The lens CPU controls the entire lens device 14. Although not shown, the AF unit 26 includes an AF processing unit, an AF imaging circuit, and the like. The AF image pickup circuit is disposed in the lens device 14 to acquire an image signal for AF processing. An image pickup device such as an image pickup device CCD (referred to as an image pickup device for AF) or an output signal of the AF image pickup device is used in a predetermined format. And a processing circuit for outputting as a video signal. The video signal output from the AF imaging circuit is a luminance signal.

  On the image pickup surface of the AF image pickup device, subject light branched from the subject light incident on the image pickup device of the camera main body 12 is imaged by a half mirror or the like disposed on the optical path of the taking lens 24. . 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 body 12. The subject image captured by the image sensor matches the subject image captured by the image sensor of the camera body 12. It should be noted that the shooting ranges of the two do not need to be completely coincident. For example, the shooting range of the AF image sensor may be a larger range including the shooting range of the image sensor of the camera body 12.

  The AF processing unit acquires a video signal from the AF imaging circuit, 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 way indicates the level of contrast of the subject image, and is given to the lens CPU as a focus evaluation value.

  The lens CPU acquires AF frame information (AF frame information) indicating the range (contour) of the AF area from the operation unit 20 through the image processing unit 18 as described later, and is designated by the AF frame information. The range within the AF frame is designated as an AF area to the AF processing unit. Then, the focus evaluation value obtained from the image (video signal) in the AF area is acquired from the AF processing unit.

  In this way, every time a video signal for one screen is acquired from the AF imaging circuit (each time the focus evaluation value is obtained by the AF processing unit), the focus evaluation value is acquired from the AF processing unit, and the acquired focus is obtained. The focus lens group is controlled so that the 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 camera body 12 and the lens device 14 are provided with tally lamps 12a and 14a informing that the TV camera 10 is in a shooting operation (ON AIR) at a place that is easy to see from the subject side.

  The camera body 12 and the lens device 14 transmit and receive various kinds of information via serial communication interfaces (SCI) 12b and 14b provided respectively. Further, the AF unit 26 of the lens device 14 and the main board 30 of the image processing unit 18 to be described later transmit and receive various information to and from the serial communication interfaces 26a and 30a provided respectively. Yes.

  The HDTV signal (HD video signal) output from the camera body 12 is displayed on the viewfinder 16 as an image captured by the television camera 10 and used for composition confirmation or the like.

  In this way, the video signal from the television camera 10 is given to the viewfinder 16, and a real-time image (video) captured by the television camera 10 is displayed on the screen of the viewfinder 16. . In addition, information such as an AF frame indicating the range of an AF area that is a target of autofocus (AF) can be displayed on the screen of the viewfinder 16.

  On the other hand, the HDTV signal output from the camera body 12 is converted (down-converted) into a standard television [NTSC (National Television System Committee)] video signal (SDTV signal) by the down converter 28 for image processing. The data is input to the unit 18.

  As will be described in detail later, the image processing unit 18 performs face authentication on the subject person in the captured subject image, and subjects (focus targets) that have been set in advance so that they are automatically tracked with autofocus. If it is recognized that the lens device 14 is, the auto focus control of the lens device 14 is performed through the AF unit 26.

  In this embodiment, at this time, the data of a plurality of persons are registered in advance, and the order of focusing is determined during shooting, and the operator sends the order at each change of scene, for example. The target of autofocus is switched according to the order.

  In addition, in order to perform face authentication and determine whether the subject currently being shot is an object to be automatically tracked with autofocus, it is not necessary to be a high-definition image using an HDTV signal. Since the image of the video signal (SDTV signal) is sufficient, the HDTV signal output from the camera body 12 is converted into the SDTV signal by the down converter 28.

  The image processing unit 18 includes blocks for performing each process on separate boards, and includes a main board 30, an authentication processing calculation board 32, and a face authentication data card 34.

  The main board 30 includes a decoder (A / D converter) 36, a CPU 38, a RAM 40, and a superimposer 42.

  As described above, the HDTV signal output from the camera body 12 is converted into the SDTV signal by the down converter 28 and input to the image processing unit 18. The decoder (A / D converter) 36 converts the SDTV signal into the SDTV signal. The converted video signal of analog data is converted into digital data for face authentication processing in the image processing unit 18.

  The CPU 38 controls the entire image processing unit 18. The RAM 40 stores information registered in advance with respect to an object to be tracked by autofocus, and a predetermined order of autofocus. The superimposer 42 is for displaying information related to the registered AF tracking target (focus target) on the display screen of the operation unit 20, which will be described later, with characters or the like superimposed on the focus target image.

  The authentication processing calculation board 32 includes a CPU 32a that executes authentication processing and a VRAM 32b that holds a display image.

  The operation unit 20 includes an LCD (liquid crystal display screen) with a touch panel, and data displayed on the LCD display screen is an NTSC / PAL (composite) signal.

  The operator designates a target (focus target) to be focused from among pre-registered targets on the touch panel display screen of the operation unit 20. Although details will be described later, the next target (number) is instructed sequentially so that the autofocus target is switched in accordance with a predetermined order. Alternatively, the operator may arbitrarily designate an autofocus target from the registered data regardless of the order.

  Data specifying the tracking target (focus target) input from the operation unit 20 is input to the CPU 38 of the main board 30 of the image processing unit 18. The CPU 38 extracts the tracking target information from the registration target stored in the RAM 40 based on the data indicating the specified tracking target, and sends it to the authentication processing calculation board 32 together with the data of the face authentication data card 34.

  The CPU 32a of the authentication processing calculation board 32 includes a focus target subject designated from these pre-registered targets, and a subject that is a photographing target represented by a video signal currently being picked up sent from the camera body 12. Face recognition is performed.

  Face authentication in the authentication processing calculation board 32 is performed by a known face authentication technique, and identifies and recognizes a registered individual face.

  For example, feature points are extracted from the imaged subject according to a predetermined algorithm. The extracted feature points include the contours of human eyes, pupils, eyebrows, nose, mouth, ears, their orientation, position, size, and the like, and the presence of hairstyles, wrinkles, and glasses. By comparing these with registered data, it is authenticated whether or not they are the same person.

  FIG. 2 shows a state in which the autofocus target is actually switched using the display screen configured by the touch panel LCD of the operation unit 20.

  FIG. 2A shows a display for the operator to select a mode. Here, for example, when the operator selects “data call” for face authentication and gives an instruction from the touch panel, data such as images of a plurality of persons registered in advance is displayed on the display screen.

  At this time, as shown in FIG. 2B, for example, it is assumed that eight persons are registered in advance from No. 1 to No. 8 in the order to be autofocused.

  In this case, for example, when shooting a TV program, the order of authentication data (registration data) is registered by confirming the order in advance by a camera rehearsal or the like.

  When shooting is started, shooting is first performed with the first person in focus. When the scene changes as the program progresses and the focus is set on the second person, when the operator touches the “INCREASE” button on the touch panel as shown in FIG. An instruction to focus on No. 2 is sent from the operation unit 20 to the CPU 38 of the main board 30 of the image processing unit 18.

  Based on this instruction, the CPU 38 transmits data necessary for face authentication of the second registered person from the RAM 40 and the face authentication data card 34 to the authentication processing calculation board 32. Then, the authentication processing calculation board 32 performs an authentication process on the person of the video data sent from the decoder 36 based on these data, and authenticates the second person.

  When the second person is authenticated, the CPU 38 of the main board 30 issues an instruction to the lens apparatus 14 via the serial communication interface 30a and the serial communication interface 26a of the AF unit 26 of the lens apparatus 14, and focuses on the second person. The lens device 14 is controlled so as to adjust the focus.

  In addition, for example, as shown in FIG. 2B, when the “DECREASE” button is touched when the third registered person is currently in focus, the order is moved to the previous one. The second person is the target of autofocus, and the lens device 14 is controlled so that the second person is in focus.

  As described above, in this embodiment, when the shooting order is determined in advance, the autofocus target is registered in accordance with the order, and the operator touches the button indicating the “next” order. By simply doing this, the autofocus target is switched one after another, so that even when there are a plurality of subjects, it is possible to easily focus on each subject one after another.

  That is, when switching scenes is determined in advance, such as when recording a script, the order of shooting is confirmed in advance by camera rehearsal, etc., the order of authentication data is registered, and the order is switched. If it is configured so that it can be sent to the system sequentially, the authentication data of the next person is called into the system when the operator presses the changeover switch when the scene changes, and the authentication process is executed automatically. Thus, the next person can be focused.

  As a result, the face authentication tracking system can be used continuously according to changes in the scene.

  In the example shown in FIG. 2B, the two buttons “INCREASE (next)” and “DECREASE (previous)” are set. However, the setting of the buttons is not limited to this. Various settings are possible. For example, an arbitrary registration target may be specified instead of sequentially specifying a number key on the screen and specifying a number.

  Alternatively, a switch by voice input may be provided so that when the operator speaks “next” by voice, the apparatus recognizes the voice and instructs the CPU 38 to switch to the “next” registration target. .

  Further, voice data of each subject to be AF tracked is registered in advance, a voice uttered by the subject at the time of shooting is picked up, and the voice is recognized to identify a person who is uttered, and The focus may be automatically adjusted.

  Further, the touch panel of the operation unit 20 may be installed at another location, for example, so that a person other than the cameraman can switch the autofocus target by operating a switch.

  Further, the autofocus target may be switched by switching while looking at the face data or name of the person registered on the touch panel display of the operation unit 20. At this time, by touching the image of each registered person displayed on the touch panel, the person image itself may be used as a switch so that the person is focused automatically.

  In addition, when performing in a multi-person group, it may be difficult for the photographer to determine which person should be focused. In such a case, for example, the AF tracking accuracy can be further improved by making it possible to additionally register the characteristics of the costumes of the performers on the day, even immediately before the start of shooting.

  The autofocus system of the present invention has been described in detail above, but the present invention is not limited to the above examples, and various improvements and modifications may be made without departing from the scope 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 a mode that switching of an autofocus object is actually performed using LCD with a touch panel of an operation part, (a) is a display for an operator to select a mode etc., (b) is registered beforehand. This is a display showing the data.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Imaging system, 10 ... Television camera, 12 ... Camera body, 12a, 14a ... Tally lamp, 12b, 14b, 26a, 30a ... Serial communication interface, 14 ... Lens apparatus, 16 ... Viewfinder, 18 ... Image processing unit, DESCRIPTION OF SYMBOLS 20 ... Operation part, 22 ... Pan head, 24 ... Shooting lens (zoom lens), 26 ... AF unit, 28 ... Down converter, 30 ... Main board, 32 ... Authentication processing calculation board, 34 ... Face authentication data card, 36 ... Decoder (A / D converter), 38 ... CPU, 40 ... RAM, 42 ... Superimposer

Claims (4)

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;
Focus target registration means for registering in advance a plurality of subjects to be focused, together with information necessary for face authentication, and the order to be focused at the time of shooting,
Focus target designating means for designating a subject to be focused during shooting from among a plurality of previously registered subjects to be focused;
Face authentication means for performing face authentication on the subject being imaged and the designated subject to be focused;
And when the face authentication determines that the subject being imaged is the same person as the designated subject to be focused, the focus adjustment by the autofocus unit is performed on the subject being imaged Autofocus system characterized by executing.   The focus target designating unit specifies the order of the subject to be focused next in accordance with a change in the shooting scene based on the order of focus target at the time of the pre-registered shooting, and thereby selects the focus target during the shooting. The autofocus system according to claim 1, wherein a subject to be designated is designated.   3. The autofocus system according to claim 1, wherein the focus target designating unit is a liquid crystal display screen having a touch panel function.   3. The autofocus system according to claim 1, wherein the focus target specifying unit has a voice recognition function, and specifies a subject to be focused by voice input. 4.

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