JP5063546B2 - Focus adjustment device, focus adjustment control method, and program - Google Patents

Description

  The present invention relates to a focus adjustment device that performs AF (autofocus) using subject information, a focus adjustment control method, and a program.

  A focus adjustment device such as a video camera detects an AF evaluation value representing sharpness from an image signal obtained by photoelectrically converting a subject image using an imaging device, and determines a focus lens position so that the AF evaluation value is maximized. The method of controlling and adjusting the focus is the mainstream. Hereinafter, this focus adjustment method is referred to as a TV-AF method.

  However, when a person is photographed by this TV-AF method, there is a problem that depending on the photographing condition and subject condition, the subject is not the person whose focus is the main subject but a background with high contrast.

Therefore, in recent years, in an imaging apparatus having a face recognition function, an AF area is set so as to include a recognized face area, and focus detection is performed (patent document 1), or human eyes are detected. A method of performing focus detection based on the result (Patent Document 2) has been proposed.
JP 2006-227080 A JP 2001-215403 A

  In the focus detection method using the face recognition function described above, an AF area is set for a face area when a human face is recognized, and for a preset area otherwise. Focus detection is performed. Therefore, when a person's face is always recognized, it is possible to focus on the person stably.

  However, in reality, if a subject changes when a person turns sideways or closes his eyes, or a camera shake occurs during shooting, the recognition accuracy of the face decreases.

  Under such conditions, the AF detection value is frequently switched between the case where the face is recognized and the case where the face is not recognized, so that the AF evaluation value greatly fluctuates and stable focusing is performed. I can't. In particular, in the case of moving image shooting, there is a high possibility that a person is constantly moving, and the influence becomes more prominent.

  Therefore, the present invention provides a focus adjustment device, a focus adjustment control method, and a program capable of performing stable focus adjustment control when a subject to be focused is focused using the subject detection function. Objective.

In order to achieve the above object, the focus adjustment apparatus of the present invention includes a detection unit that detects a characteristic part of a subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens , An AF area setting unit that sets a plurality of AF areas in areas corresponding to characteristic portions of a plurality of subjects detected by the detection unit, and an AF evaluation value generated based on an output signal from the detection unit is acquired. a focus adjustment apparatus having a focus detecting means, and AF area selection means for selecting the AF area to be used AF evaluation value from among the plurality of AF areas in accordance with the state of the plurality of AF areas, the more is detected feature portion of the plurality of the plurality of AF areas set is in the region corresponding to characteristic portions of a subject in the AF area setting means of the subject Te in the detection means When the AF area selection means, said plurality of the AF area based on the position of each AF area is grouped into a plurality of AF area group, the number of the AF area to select the largest AF area group included, selected The focus lens is moved using the AF evaluation value of the selected AF area group without using the AF evaluation value of the AF area group that is not set, and then the direction is determined, and then included in the selected AF area group Focus adjustment means for selecting an AF area for focusing from among the AF areas and moving the focus lens based on an AF evaluation value of the selected AF area to perform focusing determination .

The focus adjustment apparatus of the present invention includes a detection unit that detects a characteristic part of a subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens, and a plurality of AF areas as the detection unit. AF area setting means for setting areas corresponding to the characteristic portions of the plurality of subjects detected by the above, focus detection means for acquiring an AF evaluation value generated based on an output signal from the detection means , a focusing device having an AF area selecting means for selecting the AF area to be used AF evaluation value from among the plurality of AF areas in accordance with the state of the AF area, the plurality of subjects Te to the detection means If a region characteristic site corresponds to the characteristic portions of the plurality of subjects by the AF area setting means is detected a plurality of AF areas is set, the AF area selection The means groups the plurality of AF areas into a plurality of AF area groups based on the size of each AF area, selects the AF area group having the largest number of AF areas included, and selects the AF areas that are not selected. The focus lens is moved using the AF evaluation value of the selected AF area group without using the evaluation value to determine the direction, and then the AF area included in the selected AF area group is combined. Focus adjustment means for selecting an AF area to be focused and moving the focus lens based on an AF evaluation value of the selected AF area to perform in-focus determination .

The focus adjustment apparatus of the present invention includes a detection unit that detects a characteristic part of a subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens, and a plurality of AF areas as the detection unit. and AF area setting means for setting a region corresponding to the characteristic portions of a plurality of subjects detected by the focus detection means for obtaining the generated AF evaluation value based on an output signal from said detecting means, said plurality of An AF area selection unit that selects an AF area to use an AF evaluation value from among the plurality of AF areas according to the state of the AF area , wherein the detection unit detects a plurality of subjects. If a region characteristic site corresponds to the characteristic portions of the plurality of subjects by the AF area setting means is detected a plurality of AF areas is set, the AF area selection The means groups the plurality of AF areas into a plurality of AF area groups based on the moving direction of each AF area, selects an AF area group having a large number of AF areas included, and performs AF evaluation of AF area groups that are not selected. The focus lens is moved by using the AF evaluation value of the selected AF area without using a value, direction determination is performed, and then the AF area included in the selected AF area group is focused. A focus adjusting unit that selects an AF area for the focus detection and moves the focus lens based on an AF evaluation value of the selected AF area to perform focusing determination .

  According to the present invention, it is possible to perform stable focus adjustment control on a subject intended by a photographer, particularly when shooting a moving image.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In order to perform stable focus adjustment control, an AF evaluation value for a preset area and an AF evaluation value for an area of a characteristic part of a subject such as a face area (hereinafter referred to as a specific subject) are used in combination. It is effective.

  However, in general, a photographer generally shoots with a specific subject placed at the center of the screen, but in practice, the edge of the screen and the area shown by the dotted line in the example of FIG. A face other than the specific subject may be detected in the background or the like.

  Thus, when a plurality of faces are detected, not all of the faces are intended by the photographer. In particular, when shooting under conditions with a shallow depth of field, if the plurality of faces include perspective conflicts, there is a problem that hunting or the like occurs due to influence of unintended face area information.

  Therefore, in the following embodiment, stable focus adjustment is performed by optimizing the AF evaluation value of the face area according to the number of detected faces and the driving state of the lens (for example, the direction determination mode, the focus determination mode, etc.). Allows control to be performed.

(First embodiment)
FIG. 1 is a block diagram for explaining a configuration example of a video camera including a focus adjustment apparatus according to the first embodiment of the present invention.

  The video camera shown in FIG. 1 includes, as an imaging optical system, for example, a first fixed lens 101, a variable magnification lens 102 that moves in the optical axis direction and performs variable magnification, an aperture 103, a second fixed lens 104, and a focus lens 105. Have The focus lens 105 is a focus compensator lens that has both a function of correcting the movement of the focal plane accompanying zooming and a focusing function.

  The image sensor 106 is configured by a CCD sensor or a CMOS sensor, and includes a pixel having a plurality of photoelectric conversion units. In this pixel, a subject image can be photoelectrically converted to obtain a captured image. The CDS / AGC / AD converter 107 performs sampling, gain adjustment, and digital conversion on the output of the image sensor 106.

  The camera signal processing circuit 108 performs various types of image processing on the output signal from the CDS / AGC / AD converter 107 to generate an image signal. The display device 109 displays the image signal from the camera signal processing circuit 108. The recording device 110 records the image signal from the camera signal processing circuit 108 on a recording medium such as a magnetic tape, an optical disk, or a semiconductor memory.

  The AF gate 111 is a gate that passes only signals in a region used for focus detection among output signals of all pixels from the CDS / AGC / AD converter 107. The AF evaluation value processing circuit 112 calculates a high frequency component from a signal that has passed through the AF gate 111, a luminance difference component generated from the high frequency signal (difference between the maximum value and the minimum value of the luminance level of the signal that has passed through the AF gate 111), and the like. The AF evaluation value as the first information is generated by extraction.

  Here, the AF evaluation value represents the sharpness (contrast state) of the image generated based on the output signal from the image sensor 106, but the sharpness changes depending on the focus state of the imaging optical system. As a result, the signal indicates the focus state of the imaging optical system.

  The face detection processing circuit 113 performs face recognition processing on the image signal, detects specific subject information (reliability indicating the size, position, and likelihood of the face of the person in the shooting screen), and detects the detection. The result is transmitted to the camera / AF control unit 114.

  Based on the detection result, the camera / AF control unit 114 transmits information to the AF gate 111 so as to add an area used for focus detection to a position including a face area in the shooting screen.

  Note that the face recognition process described above is, for example, a method of extracting a skin color region from the gradation color of each pixel represented by image data and detecting a face with a matching degree with a face contour plate prepared in advance, There is a method of performing pattern recognition from extracted facial feature points such as eyes, nose and mouth.

  Further, the camera / AF control unit 114 controls the focus lens driving source 116 based on the output signal of the AF evaluation value processing circuit 112 to drive the focus lens 105 and outputs an image recording command to the recording device 110. .

  The zoom lens driving source 115 includes an actuator for moving the zoom lens 102 and a driver thereof. The focus lens driving source 116 includes an actuator for moving the focus lens 105 and a driver thereof. For example, a stepping motor, a DC motor, a vibration motor, a voice coil motor, or the like is used as the actuator of the variable power lens driving source 115 and the focus lens driving source 116.

  Next, focus adjustment control performed by the camera / AF control unit 114 will be described with reference to FIG. Each process in FIG. 4 is executed by a CPU or the like of the camera / AF control unit 114 after a control program stored in a ROM, hard disk, or the like (not shown) is loaded into the RAM.

  First, in step S401, the camera / AF control unit 114 sets the position and size of a fixed AF area for obtaining an AF evaluation value that is the basis of TV-AF control from the AF evaluation value processing circuit 112. Then, the process proceeds to step S402.

  This fixed AF area is different from the AF area set for the face area (the area corresponding to the detected face), for example, an area that is not based on the result of the face recognition processing performed by the face detection processing circuit 113. Is set.

  As another example of the fixed AF area, the area may be set to an area larger than the AF area set for the face area and including the area of the AF area.

  At this time, the filter coefficient in the AF evaluation value processing circuit 112 is set, and a plurality of band pass filters having different extraction characteristics are constructed. The extraction characteristic is the frequency characteristic of the bandpass filter, and the setting here means changing the setting value of the bandpass filter in the AF evaluation value processing circuit 112.

  In step S402, the camera / AF control unit 114 acquires information on the face detection processing result from the face detection processing circuit 113, and the process proceeds to step S403.

  In step S403, the camera / AF control unit 114 determines whether a face is detected from the information acquired in step S402. If it is detected, the process proceeds to step S404. If not detected, the process proceeds to step S416. .

  In step S404, the camera / AF control unit 114 determines whether or not a plurality of faces are detected from the information acquired in step S402. If a plurality of faces are detected, the process proceeds to step S405. Advances to step S413.

  In step S405, the camera / AF control unit 114 determines whether or not a flag indicating the face area selection state set in step S412 described later is set. If the flag is set, the process proceeds to step S407. Otherwise, the process proceeds to step S406.

  Here, the face area selection state means that several face areas whose AF evaluation values are to be monitored are being selected from a plurality of detected face areas, and a period during which a plurality of face areas are detected. continue.

  In step S406, the camera / AF control unit 114 designates all face areas detected from the information acquired in step S402 as monitoring targets for AF evaluation values, and the process proceeds to step S412.

  In the case of the example in FIG. 2, all detected face areas A, B, C, D, and E are to be monitored for AF evaluation values.

  On the other hand, in step S407, the camera / AF control unit 114 determines whether or not the TV-AF control state described later is in the direction determination mode, and if it is in the direction determination mode, the process proceeds to step S408, otherwise. If so, the process proceeds to step S410.

  In step S408, the camera / AF control unit 114 groups a plurality of face areas for each position (predetermined index), and then determines whether all the face areas belong to the same group. If all the face areas belong to the same group, the camera / AF control unit 114 proceeds to step S412; otherwise, the camera / AF control unit 114 proceeds to step S409.

  Here, a group including more face areas is defined as a main face area group. In the case of the example of FIG. 2, the grouped result is as shown in FIG. 3, and the face areas A, B, and C included in the group 1 become the main face area group. However, when there are a plurality of groups having the same number of face areas to be included, a face area group including a reference face area (described later) is set as a main face area group.

  In step S409, the camera / AF control unit 114 does not designate the face area determined not to be present in the main face area group in step S408 as the AF evaluation value monitoring target, and proceeds to step S412.

  That is, after that, the focus adjustment is performed by moving the imaging optical system based on the AF evaluation values of a plurality of face areas close to each other. As a result, in the example of FIG. 2, the positions of the face areas A, B, and C are close, but the positions of the face areas D and E are not. Not subject to monitoring.

  In step S410, the camera / AF control unit 114 determines whether the TV-AF control state described later is in the focus determination mode. If the focus determination mode is in focus determination mode, the process proceeds to step S411. Otherwise, the process proceeds to step S412.

  In step S411, the camera / AF control unit 114 designates one face area as a reference for finally focusing, and the process proceeds to step S412.

  Here, the conditions to be satisfied for designating the reference face area include those having the largest area, those in the center, those in which the face is located on the closest side, and the like. For example, when the area is the maximum, the face area B is targeted in the example of FIG. Further, in the case of the example shown in FIG.

  As described above, by reducing the face area for obtaining the AF evaluation value to be referred to when performing the focus adjustment operation and making only the appropriate face area, it is possible to focus on a desired specific subject.

  In step S412, the camera / AF control unit 114 sets the flag indicating that the face area is currently selected, continues the face selection state, and proceeds to step S415.

  In step S413, the camera / AF control unit 114 designates the detected face area as an AF evaluation value monitoring target from the information acquired in step S402, and the process proceeds to step S414.

  In step S414, the camera / AF control unit 114 clears the flag indicating the face area selection state described above, stops the face selection state, and proceeds to step S415.

  In step S415, the camera / AF control unit 114 sets an AF area for acquiring an AF evaluation value in the currently designated face area, and the process proceeds to step S417.

  In step S416, the camera / AF control unit 114 clears the flag indicating that the face area is selected, stops the face selection state, and proceeds to step S417.

  In step S417, the camera / AF control unit 114 acquires the AF evaluation value of the AF area set in steps S401 and S415, and the process proceeds to step S418.

  The AF evaluation values acquired here are added (synthesized) at a predetermined ratio and then used for the subsequent focus adjustment control. In the present embodiment, it is assumed that the AF evaluation value in each face area is stored as a history in a memory or the like. This is so that when the face area to be controlled changes, the AF evaluation values can be recombined and used by following the history.

  In step S418, the camera / AF control unit 114 performs focus adjustment by TV-AF control described later, and returns to step S401.

  Next, with reference to FIG. 5, the focus adjustment process by the TV-AF control in step S418 in FIG. 4 will be described.

  In FIG. 5, in step S501, the camera / AF control unit 114 determines whether or not the mode is the minute drive mode. If the mode is the minute drive mode, the process proceeds to step S502. If not, the process proceeds to step S508. .

  In step S502, the camera / AF control unit 114 performs a minute driving operation, and proceeds to step S503. In this minute driving operation, the focus lens is driven with a predetermined amplitude to determine whether the focus lens is in focus or in which direction the in-focus point exists. The detailed operation will be described later with reference to FIG.

  In step S503, the camera / AF control unit 114 determines whether or not in-focus determination is performed by the minute driving operation in step S502. If the in-focus determination is performed by the minute driving operation, the process proceeds to step S506. If not, the process proceeds to step S504.

  In step S504, the camera / AF control unit 114 determines whether the direction can be determined by the minute driving operation in step S502. If the direction can be determined, the camera / AF control unit 114 proceeds to step S505 and shifts to the hill-climbing operation mode. If not, the camera / AF control unit 114 continues the minute drive mode and returns to step S501.

  In step S506, the camera / AF control unit 114 stores the AF evaluation value level at the time of focusing in the memory, and then proceeds to step S507 to shift to the restart determination mode.

  Here, the restart determination mode is a flow for determining whether or not to perform minute driving (direction determination) again (steps S516 and S517).

  In step S508, the camera / AF control unit 114 determines whether or not the hill-climbing drive mode is selected. If the hill-climbing drive mode is selected, the process proceeds to step S509. If not, the process proceeds to step S513.

  In step S509, the camera / AF control unit 114 performs a hill-climbing drive operation, and proceeds to step S510. In this hill-climbing drive, the focus lens is hill-climbed and driven at a predetermined speed in the direction in which the AF evaluation value increases.

  In step S510, the camera / AF control unit 114 determines whether or not the peak position of the AF evaluation value has been found by the hill-climbing driving operation in step S509. If the peak position of the AF evaluation value is found, the camera / AF control unit 114 proceeds to step S511, otherwise returns to step S501 and continues the hill-climbing drive mode.

  If it is determined in step S510 that the peak position has been found, the focus determination mode is set after the focus lens is moved to the peak position (step S515). At this time, the face area to be subjected to the focus adjustment control is narrowed down to one (step S411 in FIG. 4).

  In step S511, the camera / AF control unit 114 sets the focus lens position where the AF evaluation value has reached its peak as the target position, and then proceeds to step S512 to shift to the stop mode.

  In step S513, the camera / AF control unit 114 determines whether the stop mode is set. If the stop mode is set, the process proceeds to step S514. If not, the process proceeds to step S516.

  In step S514, the camera / AF control unit 114 determines whether or not the focus lens has returned to the position where the AF evaluation value reaches its peak. Then, when the focus lens returns to the position where the AF evaluation value reaches the peak, the camera / AF control unit 114 proceeds to step S515 and shifts to the minute driving (focusing determination) mode. Returning to step S501, the stop mode is continued.

  In step S516, the camera / AF control unit 114 compares the current AF evaluation value level with the AF evaluation value level held in step S506, and determines whether or not the fluctuation amount is equal to or greater than a predetermined value. If the variation amount is equal to or greater than the predetermined value, the camera / AF control unit 114 proceeds to step S517 to shift to the minute driving (direction determination) mode. Otherwise, the camera / AF control unit 114 returns to step S401 and determines whether to restart. Continue mode.

  Next, with reference to FIG. 6, the minute driving operation in step S502 of FIG. 5 will be described.

  In FIG. 6, in step S601, the camera / AF control unit 114 determines whether the value of the counter indicating the operation state of minute driving is currently 0. If it is 0, the process proceeds to step S602. Advances to step S603.

  In step S602, the camera / AF control unit 114 maintains the current AF evaluation value level as a process when the focus lens 105 is on the close side, and proceeds to step S621. The AF evaluation value here is based on an image signal generated from charges accumulated in the image sensor 106 when the focus lens 105 is on the infinite side in step S610 described later.

  In step S603, the camera / AF control unit 114 determines whether or not the current counter value is 1. If 1, the process proceeds to step S604. If not, the process proceeds to step S609.

  In step S604, the camera / AF control unit 114 calculates a vibration amplitude and a center movement amplitude for driving the focus lens 105 in step S608, which will be described later, and proceeds to step S605. Usually, these amplitudes are generally set within the depth of focus.

  In step S605, the camera / AF control unit 114 compares the infinite AF evaluation value level held in step S602 with the closest AF evaluation value level held in step S610 described later. If the infinite AF evaluation value level is greater than the closest AF evaluation value level, the camera / AF control unit 114 proceeds to step S606, and the closest AF evaluation value level is the infinite AF evaluation value level. If larger, the process proceeds to step S607.

  In step S606, the camera / AF control unit 114 adds the vibration amplitude and the center movement amplitude to obtain a drive amplitude, and proceeds to step S608.

  In step S607, the camera / AF control unit 114 sets the vibration amplitude as the drive amplitude, and proceeds to step S608.

  In step S608, the camera / AF control unit 114 drives the focus lens 105 in an infinite direction based on the drive amplitude obtained in step S606 or step S607, and proceeds to step S616.

  In step S609, the camera / AF control unit 114 determines whether the current counter value is 2. If it is 2, the process proceeds to step S610, and if not, the process proceeds to step S611.

  In step S610, the camera / AF control unit 114 maintains the current AF evaluation value level as processing when the focus lens 105 is on the infinity side, and proceeds to step S621. The AF evaluation value here is based on the image signal generated from the charge accumulated in the image sensor 106 when the focus lens 105 is on the close side in step S602.

  In step S611, the camera / AF control unit 114 calculates a vibration amplitude and a center movement amplitude for driving the focus lens 105 in step S615, which will be described later, and proceeds to step S612. Usually, these amplitudes are generally set within the depth of focus.

  In step S612, the camera / AF control unit 114 compares the near-side AF evaluation value level held in step S610 with the infinite-side AF evaluation value level held in step S602. If the closest AF evaluation value level is greater than the infinite AF evaluation value level, the camera / AF control unit 114 proceeds to step S613, and the infinite AF evaluation value level is the closest AF evaluation value level. If larger, the process proceeds to step S614.

  In step S613, the camera / AF control unit 114 adds the vibration amplitude and the center movement amplitude to obtain a drive amplitude, and the process proceeds to step S615.

  In step S614, the camera / AF control unit 114 sets the vibration amplitude as the drive amplitude, and proceeds to step S615.

  In step S615, the camera / AF control unit 114 drives the focus lens 105 in the closest direction based on the drive amplitude obtained in step S613 or step S614, and proceeds to step S616.

  In step S616, the camera / AF control unit 114 determines whether the current mode is the direction determination mode. If the mode determination mode is selected, the process proceeds to step S617; otherwise, the process proceeds to step S619.

  In step S617, the camera / AF control unit 114 determines whether the in-focus point exists in the same direction continuously for a predetermined number of times. If it exists, the process proceeds to step S618, and if it does not exist, Proceed to step S621.

  In step S618, the camera / AF control unit 114 determines that the direction has been determined, and proceeds to step S621.

  In step S619, the camera / AF control unit 114 determines whether the focus lens 105 has reciprocated in the same area a predetermined number of times. If it has reciprocated, the process proceeds to step S620. If it has not reciprocated, step S621 is performed. Proceed to

  In step S620, the camera / AF control unit 114 determines that the in-focus determination has been made, and proceeds to step S621.

  In step S621, the camera / AF control unit 114 returns to 0 if the counter value indicating the micro-drive operation state is 3, and adds the counter value if it is any other value.

  FIG. 7 shows the time course of the focus lens operation in this minute driving.

  The upper part of the figure is a vertical synchronizing signal of the image signal, and the lower part of the figure shows the time on the horizontal axis and the position of the focus lens 105 on the vertical axis.

  The AF evaluation value EVA for the charge accumulated in the image sensor 106 at the time of label A is taken into the camera / AF control unit 114 at time TA. Also, the AF evaluation value EVB for the charge accumulated in the image sensor 106 at the time of label B is taken into the camera / AF control unit 114 at time TB.

  At time TC, the AF evaluation values EVA and EVB are compared, and the vibration center is moved only when EVB in the figure is large. Here, the movement of the focus lens 105 is set to a movement amount that cannot be recognized on the screen on the basis of the depth of focus.

  Next, with reference to FIG. 8, the hill-climbing driving operation in step S509 in FIG. 5 will be described.

  In FIG. 8, in step S701, the camera / AF control unit 114 sets the drive speed of the focus lens 105, and the process proceeds to step S702.

  In step S702, the camera / AF control unit 114 determines whether or not the current AF evaluation value level has increased from the previous time. If it has increased, the process proceeds to step S703, and if not, step S704 is performed. Proceed to

  In step S703, the camera / AF control unit 114 drives the focus lens 105 to climb in the same forward direction as the previous time based on the driving speed set in step S701.

  In step S704, the camera / AF control unit 114 determines whether or not the AF evaluation value level has decreased beyond the peak position. If the AF evaluation value level has exceeded the peak position, the process proceeds to step S705. The process proceeds to step S706.

  In step S705, the camera / AF control unit 114 determines that a peak position has been found.

  In step S706, the camera / AF control unit 114 drives the focus lens 105 to climb in the direction opposite to the previous time based on the driving speed set in step S701. If step S706 is repeated in the hill-climbing drive mode, it means that the focus lens 105 is in the hunting state because a sufficient amount of change in the AF evaluation value of the subject cannot be obtained.

  FIG. 9 shows the operation of the focus lens in this hill-climbing drive.

  In the same figure, when the focus lens 105 is driven like A, since the AF evaluation value is increasing, the mountain climbing drive in the same direction is continued.

  Here, when the focus lens 105 is driven in the range of B, the AF evaluation value decreases beyond the peak position. At this time, the hill-climbing driving operation is terminated assuming that the in-focus point exists, and after the focus lens 105 is returned to the peak position, the operation shifts to the minute driving operation.

  On the other hand, when the AF evaluation value decreases without exceeding the peak position as in C, the direction to be driven is reversed and the hill-climbing driving operation is continued.

  As described above, in the present embodiment, in the focus adjustment control by the TV-AF method, the focus lens 105 is moved while repeating restart determination → micro drive → mountain climbing drive → stop → micro drive → restart determination. Thereby, the in-focus state can be maintained so that the AF evaluation value is always maximized.

  Further, the AF evaluation value used for the focus adjustment control can be effectively obtained from the face area designated according to the control state. For this reason, it is possible to provide a stable focus adjustment operation for the person of the specific subject intended by the photographer at all times, particularly during moving image shooting.

  Further, in the direction determination mode in which the direction is determined at a position away from the in-focus position (second area) in the movement range of the focus lens 105, the AF area is enlarged to increase the AF area. Accuracy can be improved. This is because stable AF can be performed by using a lot of information.

  Further, in the focus determination mode in which the focus lens 105 is positioned in the vicinity of the focus position (first area) and is driven minutely, the face area is narrowed down to one, so that a desired subject can be selected. To focus.

(Second Embodiment)
Next, with reference to FIG. 4, a video camera including a focus adjustment apparatus according to the second embodiment of the present invention will be described.

  In the first embodiment, the case where a plurality of face areas are grouped for each position is illustrated in step S408 of FIG. 4, but in the present embodiment, a plurality of face areas are grouped for each size. Take as an example.

  That is, in FIG. 4, in step S <b> 408, the camera / AF control unit 114 groups a plurality of face areas according to size, and then determines whether all face areas belong to the same group. The camera / AF control unit 114 proceeds to step S412 when all the face areas belong to the same group, and proceeds to step S409 when they do not belong to the same group.

  Here, a group including more face areas is defined as a main face area group. In the case of the example of FIG. 2, the grouped result is as shown in FIG. 3, and the face areas A, B, and C included in the group 1 become the main face area group. However, when there are a plurality of groups having the same number of face areas to be included, the face area group including the reference face area is set as the main face area group.

  In step S409, the camera / AF control unit 114 does not specify the face area determined not to exist in the main face area group in step S408 as the AF evaluation value monitoring target. That is, after that, the focus adjustment is performed by moving the imaging optical system based on the AF evaluation values of a plurality of face areas having similar sizes. As a result, in the case of the example in FIG. 2, the face areas A, B, and C are close in size, but the face areas D and E are not close in size. The value is not monitored. Other configurations and operational effects are the same as those of the first embodiment.

(Third embodiment)
Next, with reference to FIG. 4, a video camera provided with a focus adjustment apparatus according to the third embodiment of the present invention will be described.

  In the first embodiment, the case where a plurality of face areas are grouped for each position is illustrated in step S408 of FIG. 4, but in the present embodiment, a plurality of face areas are grouped for each movement direction. Take as an example.

  That is, in FIG. 4, in step S <b> 408, the camera / AF control unit 114 groups a plurality of face areas for each movement direction, and then determines whether all face areas belong to the same group. The camera / AF control unit 114 proceeds to step S412 when all the face areas belong to the same group, and proceeds to step S409 when they do not belong to the same group.

  Here, a group including more face areas is defined as a main face area group. In the case of the example of FIG. 2, the grouped result is as shown in FIG. 3, and the face areas A, B, and C included in the group 1 become the main face area group. However, when there are a plurality of groups having the same number of face areas to be included, the face area group including the reference face area is set as the main face area group.

  In step S409, the camera / AF control unit 114 does not specify the face area determined not to exist in the main face area group in step S408 as the AF evaluation value monitoring target. That is, thereafter, the imaging optical system is moved based on the AF evaluation values of a plurality of face areas having the same moving direction, and focus adjustment is performed. As a result, in the example of FIG. 2, the movement directions of the face areas A, B, and C are equal, but the movement directions of the face areas D and E are not equal. Is not subject to monitoring. Other configurations and operational effects are the same as those of the first embodiment.

  In addition, this invention is not limited to what was illustrated by said each embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

  For example, in each of the above embodiments, the video camera has been described. However, the present invention can be applied to other imaging apparatuses such as a digital still camera, and a focus adjustment apparatus incorporated in a microscope or the like.

  Further, in each of the above embodiments, when the focus adjustment operation is performed, information indicating which face area information the focus adjustment operation is performed on may be displayed on the display device 109.

  Further, in each of the embodiments described above, the AF area is set to the position of the detected face in the imaging screen. However, a specific subject may be detected by cutting out a subject image from another image, for example, a background image. . In addition, the position in the imaging screen may be determined by inputting the position in the imaging screen from an external input means or by detecting the line of sight of the photographer who is looking at the viewfinder.

  Furthermore, the object of the present invention is achieved by executing the following processing. That is, a storage medium that records a program code of software that realizes the functions of the above-described embodiments is supplied to a system or apparatus, and a computer (or CPU, MPU, etc.) of the system or apparatus is stored in the storage medium. This is the process of reading the code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code and the storage medium storing the program code constitute the present invention.

  Moreover, the following can be used as a storage medium for supplying the program code. For example, floppy (registered trademark) disk, hard disk, magneto-optical disk, CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD + RW, magnetic tape, nonvolatile memory card, ROM or the like. Alternatively, the program code may be downloaded via a network.

  Further, the present invention includes a case where the function of the above-described embodiment is realized by executing the program code read by the computer. In addition, an OS (operating system) running on the computer performs part or all of the actual processing based on an instruction of the program code, and the functions of the above-described embodiments are realized by the processing. Is also included.

  Furthermore, a case where the functions of the above-described embodiment are realized by the following processing is also included in the present invention. That is, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

It is a block diagram for demonstrating the structural example of a video camera provided with the focus adjustment apparatus which is the 1st Embodiment of this invention. It is a figure which shows the example of a face area when a some face is detected. It is a figure which shows the result of having grouped each face area of FIG. It is a flowchart for demonstrating the focus adjustment control performed by a camera / AF control part. It is a flowchart for demonstrating the focus adjustment control performed by a camera / AF control part. FIG. 5 is a flowchart for explaining focus adjustment processing by TV-AF control in step S418 in FIG. 4; FIG. 5 is a flowchart for explaining focus adjustment processing by TV-AF control in step S418 in FIG. 4; FIG. 6 is a flowchart for explaining a minute driving operation in step S502 of FIG. FIG. 6 is a flowchart for explaining a minute driving operation in step S502 of FIG. It is a graph which shows the relationship between the position of the focus lens in micro drive, and time. FIG. 6 is a flowchart for explaining a hill-climbing driving operation in step S509 of FIG. It is a graph which shows the relationship between the position of the focus lens in a hill-climbing drive operation, and AF evaluation value.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 1st fixed lens 102 Variable magnification lens 103 Diaphragm 104 2nd fixed lens 105 Focus lens 106 Image pick-up element 107 CDS / AGC / AD converter 108 Camera signal processing circuit 109 Display apparatus 110 Recording apparatus 111 AF gate 112 AF evaluation value processing circuit 113 Face detection processing circuit 114 Camera / AF control unit 115 Variable magnification lens drive source 116 Focus lens drive source

Claims (13)

Detection means for detecting a characteristic part of the subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens ;
AF area setting means for setting a plurality of AF areas in areas corresponding to characteristic portions of a plurality of subjects detected by the detection means;
Focus detection means for obtaining an AF evaluation value generated based on an output signal from the detection means;
A focusing device having an AF area selecting means for selecting the AF area to be used AF evaluation value from among the plurality of AF areas in accordance with the state of the plurality of AF areas,
If the area corresponding to the characteristic portions of the plurality of subjects are detected characteristic portions of a plurality of subjects in the AF area setting means a plurality of AF areas set Te to said detecting means,
The AF area selection unit groups the plurality of AF areas into a plurality of AF area groups based on the positions of the respective AF areas, selects an AF area group having the largest number of AF areas included, and is not selected. The focus lens is moved using the AF evaluation value of the selected AF area group without using the AF evaluation value of the group to determine the direction, and then the AF area included in the selected AF area group is determined. A focus adjustment device having a focus adjustment unit that selects an AF area for focusing from among them and moves the focus lens based on an AF evaluation value of the selected AF area to perform focusing determination . Detection means for detecting a characteristic part of the subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens ;
AF area setting means for setting a plurality of AF areas in areas corresponding to characteristic portions of a plurality of subjects detected by the detection means;
Focus detection means for obtaining an AF evaluation value generated based on an output signal from the detection means;
A focusing device having an AF area selecting means for selecting the AF area to be used AF evaluation value from among the plurality of AF areas in accordance with the state of the plurality of AF areas,
If the area corresponding to the characteristic portions of the plurality of subjects are detected characteristic portions of a plurality of subjects in the AF area setting means a plurality of AF areas set Te to said detecting means,
The AF area selecting means groups the plurality of AF areas into a plurality of AF area groups based on the size of each AF area, selects an AF area group having the largest number of AF areas included, and is not selected. The focus lens is moved using the AF evaluation value of the selected AF area group without using the AF evaluation value of the area group to determine the direction, and then the AF areas included in the selected AF area group A focus adjustment device having a focus adjustment unit that selects an AF area to be focused from among the two, moves the focus lens based on an AF evaluation value of the selected AF area, and performs focus determination . Detection means for detecting a characteristic part of the subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens;
AF area setting means for setting a plurality of AF areas in areas corresponding to characteristic portions of a plurality of subjects detected by the detection means;
Focus detection means for obtaining an AF evaluation value generated based on an output signal from the detection means;
An AF area selection unit that selects an AF area to use an AF evaluation value from among the plurality of AF areas according to the state of the plurality of AF areas,
When the detection unit detects feature parts of a plurality of subjects, and the AF area setting unit sets a plurality of AF areas in areas corresponding to the feature parts of the plurality of subjects,
The AF area selecting means groups the plurality of AF areas into a plurality of AF area groups based on the movement direction of each AF area, selects an AF area group having a large number of included AF areas, and selects an AF area that is not selected. Using the AF evaluation value of the selected AF area without using the AF evaluation value of the group, the focus lens is moved to determine the direction, and then among the AF areas included in the selected AF area group A focus adjustment device having a focus adjustment unit that selects an AF area to be focused from, and moves the focus lens based on an AF evaluation value of the selected AF area to perform focus determination . The focus adjustment apparatus according to any one of claims 1 to 3, wherein the characteristic part of the subject is a face . The AF area selected for performing focusing determination is focusing device according to any one of claims 1 to 4 area of the AF area is the AF area is the maximum. The AF area selected for performing focusing determination is focusing device according to what Re one of claims 1 to 4 the position of the AF area is the AF area closest to the center position. The AF area selected for performing focusing determination is focusing device according to any one of claims 1 to 4 which is the AF area the AF area is located on the nearest side. A detection step of detecting a characteristic part of the subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens;
An AF area setting step for setting a plurality of AF areas in regions corresponding to characteristic portions of a plurality of subjects detected in the detection step;
A focus detection step of obtaining an AF evaluation value generated based on the output signal in the detection step;
An AF area selection step of selecting an AF area to use an AF evaluation value from among the plurality of AF areas according to the state of the plurality of AF areas,
When a plurality of subject areas are detected in the detection step and a plurality of AF areas are set in regions corresponding to the plurality of subject feature parts in the AF area setting step,
In the AF area selecting step, the plurality of AF areas are grouped into a plurality of AF area groups based on positions of the respective AF areas, an AF area group having a large number of AF areas is selected, and an AF area group that is not selected is selected. The focus lens is moved using the AF evaluation value of the selected AF area group without using the AF evaluation value of the selected AF area, and direction determination is performed. Thereafter, among the AF areas included in the selected AF area group A focus adjustment control method including a focus adjustment step of selecting an AF area to be focused from and moving the focus lens based on an AF evaluation value of the selected AF area to perform focusing determination . A detection step of detecting a characteristic part of the subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens ;
An AF area setting step for setting a plurality of AF areas in regions corresponding to characteristic portions of a plurality of subjects detected in the detection step;
A focus detection step of obtaining an AF evaluation value generated based on the output signal in the detection step;
A focusing control method and a AF area selection step of selecting the AF area to be used AF evaluation value from among the plurality of AF areas in accordance with the state of the plurality of AF areas,
When a plurality of subject areas are detected in the detection step and a plurality of AF areas are set in regions corresponding to the plurality of subject feature parts in the AF area setting step ,
In the AF area selection step, the plurality of AF areas are grouped into a plurality of AF area groups based on the size of each AF area, an AF area group having a large number of AF areas is selected, and AF areas that are not selected are selected. The focus lens is moved using the AF evaluation value of the selected AF area group without using the AF evaluation value of the group to determine the direction, and then the AF area included in the selected AF area group is determined. A focus adjustment control method including a focus adjustment step of selecting an AF area for focusing from among them and moving the focus lens based on an AF evaluation value of the selected AF area to perform focusing determination . A detection step of detecting a characteristic part of the subject from a captured image obtained by photoelectrically converting a subject image that has passed through a photographing optical system including a focus lens ;
An AF area setting step for setting a plurality of AF areas in regions corresponding to characteristic portions of a plurality of subjects detected in the detection step;
A focus detection step of obtaining an AF evaluation value generated based on the output signal in the detection step;
A focusing control method and a AF area selection step of selecting the AF area to be used AF evaluation value from among the plurality of AF areas in accordance with the state of the plurality of AF areas,
When a plurality of subject areas are detected in the detection step and a plurality of AF areas are set in regions corresponding to the plurality of subject feature parts in the AF area setting step ,
In the AF area selection step, the plurality of AF areas are grouped into a plurality of AF area groups based on the moving direction of each AF area, an AF area group having a large number of AF areas is selected, and AF areas that are not selected are selected. The focus lens is moved using the AF evaluation value of the selected AF area group without using the AF evaluation value of the group to determine the direction, and then the AF area included in the selected AF area group is determined. A focus adjustment control method including a focus adjustment step of selecting an AF area for focusing from among them and moving the focus lens based on an AF evaluation value of the selected AF area to perform focusing determination . A program for causing a computer to execute the focus adjustment control method according to claim 8 . A program for causing a computer to execute the focus adjustment control method according to claim 9 . A program for causing a computer to execute the focus adjustment control method according to claim 10.

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