JP5683159B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus such as a video camera.

  Japanese Patent Application Laid-Open No. 2004-228561 automatically selects a duration in a manual selection mode in a mode for automatically selecting a main subject, a mode for manually selecting, and an imaging apparatus that continues to display an area for a set time after the main subject is last selected Propose to be longer than mode. Also known is an auto zoom mode in which the focal length is adjusted so that the main subject is maintained at a constant size.

JP 2009-44461 A

  If the subject distance is long in auto zoom, the subject is likely to be blocked by an obstacle or to be out of the angle of view due to camera shake.As a result, if the subject is lost and the auto zoom control is stopped once, it becomes complicated. The auto zoom mode must be reset.

  An object of the imaging apparatus of the present invention is to provide an imaging apparatus capable of continuing the auto zoom process even when the focal length is long.

The image pickup apparatus according to the present invention includes a detection unit that detects a main subject that satisfies a condition from an input image signal, and the detection unit cannot detect the main subject when the imaging optical system has a first focal length. The automatic zoom process for driving the photographic optical system in accordance with the main subject detected by the detecting means when the duration of 1 has elapsed and the second photographic optical system is longer than the first focal length A controller that controls to end the auto-zoom process when a second duration longer than the first duration has elapsed since the detection means could not detect the main subject at the focal length. and, wherein by the controller in the auto zoom process, also the last main object scene when the main object of the drive factors no longer detected when not driving the imaging optical system There and changes the focal length worth of varied when detected.

  According to the present invention, it is possible to provide an imaging apparatus capable of continuing the auto zoom process even when the focal length is long.

It is a block diagram of an imaging device. 3 is a flowchart for explaining an operation of the CPU shown in FIG. 1 in an auto zoom mode. Example 1 FIG. 2 is a graph for explaining the method of setting the auto zoom duration in S130. 6 is a flowchart for explaining another operation of the CPU shown in FIG. 1 in the auto zoom mode. (Example 2)

  FIG. 1 is a block diagram of a video camera (imaging device) according to an embodiment of the present invention. The type of the imaging apparatus of the present invention is not limited as long as the camera has an auto zoom mode.

  In FIG. 1, reference numeral 101 denotes a lens (photographing optical system) that forms an optical image of a subject, a zoom lens 101a that moves in the optical axis direction during zooming, and an optical axis during focus adjustment (focusing). A focus lens 101b that moves in the direction.

  Reference numeral 102 denotes an image sensor such as a CCD or CMOS that photoelectrically converts an optical image formed by the lens 101 into an electrical signal. A signal processing circuit 103 converts the charge generated by the image sensor 102 into a video signal having a predetermined format. The signal processing circuit 103 functions as a detection unit that detects a subject that satisfies a set condition such as a face or a color from an image signal input from the image sensor 102. A lens control circuit 104 performs drive control of the lens 101, and performs drive control of the zoom lens 101a and the focus lens 101b in the optical axis direction.

  Reference numeral 105 denotes a CPU (controller) as a system control unit that controls the entire system of the video camera, and includes a microcomputer (processor).

  The CPU 105 also functions as auto zoom processing means for automatically adjusting the focal length so that the main subject selected via the lens control circuit 104 and the zoom lens 101a is maintained at a constant size in the auto zoom mode. To do. More specifically, the CPU 105 automatically determines the appropriate magnification based on the subject distance by the distance measuring unit 114, automatically zooms the lens 101 so that the main subject is maintained at a certain size, In addition, focusing is performed by autofocus (automatic focus adjustment).

  Reference numeral 112 denotes a RAM which serves as a work area for the CPU 105. Reference numeral 113 denotes a ROM having a program necessary for controlling the video camera.

  Reference numeral 106 denotes a recording medium such as a DVD, a hard disk, or a nonvolatile memory. Reference numeral 107 denotes a recording medium control circuit for controlling data input / output with the recording medium 106.

  Reference numeral 108 denotes a monitor (display means) for outputting a video being shot and a reproduced video. Reference numeral 109 denotes a playback circuit for playing back the video read from the recording medium 106 on the monitor 108. Reference numeral 110 denotes an OSD (On Screen Display) circuit for displaying a menu and shooting information on the monitor 108.

  Reference numeral 111 denotes operation keys for the user to operate the video camera, and functions as setting means for setting various modes including the auto zoom mode. In the auto zoom mode, the operation key 111 can select the main subject according to the user input.

  Reference numeral 114 denotes a distance measuring unit that measures the subject distance. Reference numeral 115 denotes an external input / output unit, which can output captured images to an external monitor or recorder, or input images from another video camera or player. Alternatively, the video camera can be connected to a computer via the external input / output unit 115, and necessary information can be acquired via the computer and the Internet.

  In the first embodiment, when the main subject cannot be detected during auto-zoom, the CPU 105 ends the subject within the duration (for example, the first duration) set according to the focal length at that time. The focal length (for example, the first focal length) at the time of detecting is maintained.

  FIG. 2 is a flowchart for explaining the operation of the CPU 105 according to the first embodiment in the auto zoom mode, and “S” is an abbreviation for a step. The flowchart shown in FIG. 2 can be embodied as a program for causing a computer to perform each step, and is stored in the ROM 113. Such a program can be acquired and updated via the Internet as described above. Of course, the program may be supplied by a recording medium such as the recording medium 106.

  When the auto zoom mode is set by the operation key 111, the CPU 105 first determines whether or not the user has selected the main subject using the operation key 111 (S100). The CPU 105 waits until a main subject is selected (No loop in S100).

  When the CPU 105 determines that the main subject has been selected (Yes in S100), the zoom lens 101a is set via the lens control circuit 104 so that the size of the main subject detected by the signal processing circuit 103 becomes the set size. Is driven (moved) in the optical axis direction. As a result, the CPU 105 changes the focal length (S110). At this time, the CPU 105 also performs autofocus by moving the focus lens 101b in the optical axis direction via the lens control circuit 104.

  Next, the CPU 105 determines whether or not the main subject is detected by the signal processing circuit 103 (S120). If it is determined that the main subject is detected (Yes in S120), the CPU 105 returns to S110 and continues the auto zoom. To do.

  On the other hand, when the CPU 105 determines that the main subject is no longer detected by the signal processing circuit 103 (No in S120), the auto zoom after the main subject cannot be detected when the lens 101 is at the first focal length. A duration is set (S130).

  FIG. 3 is a graph for explaining the setting method of the auto zoom duration in S130, and the CPU 105 sets the auto zoom duration to be longer as the focal length is longer. For example, if the focal length is X and the duration is Y, it is set by the equation Y = aX + b. Here, a and b are constants obtained from the graph shown in FIG. For this reason, the CPU 105 sets the second duration longer than the first duration set for the first focal length for the second focal length longer than the first focal length of the lens 101. Set.

  In this way, when the focal length (or subject distance) is long, if the subject can be detected again within the auto zoom duration after losing sight of the subject, auto zoom can be continued, so auto zoom continues. Auto-zoom stabilizes over time.

  Next, the CPU 105 determines whether or not the time elapsed since the main subject was last detected is longer than the duration set in S130 (that is, whether or not the duration has elapsed) (S140). If the CPU 105 determines that the set duration is longer than the elapsed time (No in S140), the CPU 105 determines whether the main subject has been detected (S150).

  If the CPU 105 determines that the main subject has not been detected (No in S150), the CPU 105 returns to S140 and determines again whether the elapsed time has exceeded the set duration. Unless the main subject is detected within the duration time, the flow of S140 and S150 is repeated. During this time, the CPU 105 does not change the focal length and maintains the focal length that was set when the main subject was last detected.

  If the CPU 105 determines that the main subject has been detected within the duration (Yes in S150), the CPU 105 returns to S110 and continues the auto zoom.

  If the CPU 105 determines that the elapsed time has exceeded the first duration (Yes in S140), the CPU 105 ends the auto zoom process. As described above, the CPU 105 determines that the second focal length longer than the first focal length of the lens 101 is longer than the first duration set for the first focal length. Set the duration. For this reason, the CPU 105 performs control so as to end the auto zoom process when the main object cannot be detected when the lens 101 has the first focal length and the first duration has elapsed. Further, the CPU 105 performs control so as to end the auto zoom process when the main object cannot be detected when the lens 101 is at the second focal length and the second duration has elapsed.

  According to the first embodiment, in a state in which the focal length is long, the auto zoom can be continued for a longer time even if the subject is lost due to camera shake or an obstacle, and the auto zoom can be stabilized. In particular, the auto zoom can be continued when there is little movement forward and backward of the subject.

  In the second embodiment, when the main subject cannot be detected during the auto-zoom process, the CPU 105 changes the amount of change when the subject is last detected for the duration set according to the focal length at that time. Change the focal length. For example, the CPU 105 repeats the change of the first focal length by the amount changed last during the first duration.

  FIG. 4 is a flowchart for explaining the operation of the CPU 105 in the auto zoom mode according to the second embodiment, and “S” is an abbreviation for a step. In FIG. 4, S100 to S140 are the same as those in FIG. After No in S140, the CPU 105 determines whether or not the main subject has been detected (S150). If it is determined that the main subject has been detected, the CPU 105 returns to S110 as in FIG.

  On the other hand, if the CPU 105 determines that the main subject has not been detected (No in S150), the CPU 105 changes the focal length by the same amount as the amount changed in S110 when the main subject was detected last. (S160). After S160, the flow proceeds to S140, and the CPU 105 determines again whether the elapsed time exceeds the duration time.

  As long as the elapsed time does not exceed the set duration, unless the main subject is detected, the CPU 105 repeats the flow of S140 to S160, and during this time, the focal length is changed in S160. Thereby, after the main subject is re-detected in S120 for the main subject that continues to move in the same direction with respect to the camera, the focal length does not change much in S110.

  According to the second embodiment, in a state where the focal length is long, the auto zoom can be continued for a longer time even if the subject is lost sight due to camera shake or an obstacle, and the auto zoom can be stabilized. Also, if the main subject keeps moving in the same direction with respect to the camera, the continuity of the video is maintained without changing the focal length significantly when re-detecting after losing sight of the main subject. It becomes possible.

  In the first and second embodiments, auto zoom has been described, but these can also be applied to auto focus (AF). In this case, the CPU 105 performs AF by moving the focus lens 101 b of the lens 101 in the optical axis direction via the lens control circuit 104 according to the main subject detected by the signal processing circuit 103. Then, when the signal processing circuit 103 becomes unable to detect the subject during AF, the CPU 105 continues the AF for the set duration after the main subject is detected last, and ends the AF when the duration has elapsed. To do.

The computer sets the duration longer as the focal length becomes longer. As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to these embodiments, and within the scope of the gist of the present invention. Various modifications and changes are possible.

  The imaging device can be applied to use for imaging a subject.

101 Imaging optical system 103 Signal processing circuit (detection means)
105 CPU (microcomputer)

Claims (3)

Detecting means for detecting a main subject satisfying the condition from the input image signal;
When the photographic optical system is at the first focal length, the photographic optical system is driven according to the main subject detected by the detecting means when the first continuation time has elapsed since the detecting means can no longer detect the main subject. The auto-zoom process is terminated, and when the photographing optical system has a second focal length longer than the first focal length, the detection means cannot detect the main subject and is longer than the first duration. A controller that controls to end the auto-zoom processing when a second duration has elapsed,
In the auto-zoom processing by the controller, even when the main subject of the driving factor cannot be detected when the photographing optical system is driven , the focal length changed when the main subject is detected last is detected. An imaging apparatus characterized by changing the above. The image pickup apparatus according to claim 1 , wherein the auto zoom process is a process of driving a photographing optical system in accordance with a size of a main subject image detected by the detection unit. The auto-zoom process, the imaging apparatus according to claim 1 or 2, wherein the size of the main object image detected by said detecting means is a processing for driving the photographing optical system so as to be constant.