JP4853447B2 - Digital camera, focus control system thereof, focus control method, focus control program - Google Patents

Description

  The present invention relates to a digital camera having an autofocus function, a focus control system thereof, a focus control method, and a focus control program.

  Conventionally, a digital camera that captures an image of a subject using a CCD or MOS type solid-state image sensor usually has an AF (autofocus) function. When using the AF function for still image shooting, a through image is displayed. In general, an AF area for indicating a position to be focused within an angle of view is displayed in a monitor. In many cases, the AF area is set at the center of the monitor, but when shooting, it may be desired to focus on a specific subject located outside the shooting range (center of the screen) where the AF area is set. . In that case, it is necessary to shake the camera once to position a specific subject in the center of the shooting range, then focus, and then shake the camera again so that the specific subject is located outside the center of the shooting range. There is. For this reason, the user is forced to perform a troublesome operation of shaking the camera repeatedly.

Here, for example, in Patent Document 1 below, a plurality of AF areas are provided, and the user selects a desired AF area by operating the changeover switch from among the multi (multiple) AF areas, so that other than the center of the shooting range A technique for focusing on a specific subject located at the position is disclosed. According to the technique of Patent Document 1, if the subject to be focused is located within the range of the multi-AF area when the user first holds the camera, the camera can be moved to a position other than the center of the shooting range without shaking the camera. It is possible to focus on the subject that is positioned.
JP 2001-128056 A

  However, even in the technique of Patent Document 1, when focusing on a subject outside the range of the multi-AF area, the desired AF area is operated by operating the changeover switch after the camera is shaken and the range of the AF area is superimposed on the subject. There is a problem that it is necessary to select and focus on the image.

  Therefore, the present invention has been made in view of such a conventional problem, a digital camera that can easily focus on a subject located at an arbitrary place in a shooting range, and a focus control system thereof, It is an object to provide a focus control method and a focus control program.

In order to solve the above-described problem, in the digital camera according to the first aspect of the present invention, in a digital camera having an autofocus function, an imaging unit that captures a subject image and acquires the image is acquired by the imaging unit. A first setting unit that sets a first focus detection region in the captured image, and a detection unit that detects an irradiation position of predetermined instruction light irradiated to the subject from the image acquired by the imaging unit Second setting means for setting a second focus detection area corresponding to the irradiation position detected by the detection means in the image acquired by the imaging means, and image information of the first focus detection area in preference to the auto-focus processing based on, and control means for causing the auto focus processing based on the image information of the second focus detection area, before After the irradiation position is once detected by the detection means, the measurement means for measuring the elapsed time after the irradiation position cannot be detected by the detection means, and the elapsed time measured by the measurement means has reached a predetermined time And an imaging control unit that causes the imaging unit to perform an imaging operation for recording the captured image .

  Further, in the digital camera according to the second aspect of the invention, the detection unit detects an irradiation position of the instruction light that is irradiated from the outside and blinks at a constant cycle from the image acquired by the imaging unit. It is characterized by doing.

  In the digital camera according to a third aspect of the invention, the detection means includes extraction means for extracting pixel information of a color component similar to the color of the instruction light from an image acquired by the imaging means. And the irradiation position of the indicator light is detected based on the pixel information extracted by the extracting means.

In the digital camera according to a fourth aspect of the present invention, the first setting means sets a plurality of the first focus detection areas in the image acquired by the imaging means, and the imaging means Display means for displaying the acquired image as a through image, and display control means for displaying a plurality of focus frames respectively indicating the plurality of first focus detection areas in the image on the display means, The control means responds to the selection operation of any one of the plurality of focus frames displayed on the display means by the display control means, stops the irradiation position detection operation by the detection means, and that to perform auto-focus processing based on the image information of the focus detection area corresponding to the focus frame selected by the selection operation And butterflies.

Further, in the focus control system according to the invention of claim 5, wherein irradiating means for irradiating a pointing light of a Jo Tokoro with respect object, a digital camera having an autofocus function, capturing a subject image An imaging unit that acquires an image, a first setting unit that sets a first focus detection area in the image acquired by the imaging unit, and an image acquired by the imaging unit by the irradiation unit. A detection unit that detects an irradiation position of the predetermined instruction light that has been irradiated, and a second focus detection region that corresponds to the irradiation position detected by the detection unit is set in an image acquired by the imaging unit. 2 based on the image information of the second focus detection area in preference to the auto-focus process based on the setting means and the image information of the first focus detection area. Ku and control means for causing the auto focus processing, after the irradiation position is detected once by the detection unit, a measuring unit irradiation position to measure the elapsed time after that can no longer detected by said detecting means, by said measuring means A digital camera comprising: an imaging control unit that causes the imaging unit to perform an imaging operation for recording a captured image, triggered by a measured elapsed time reaching a predetermined time. And

According to a sixth aspect of the present invention, there is provided a focus control method for a digital camera having an autofocus function, wherein the first focus detection area is set in a captured image. Setting step, a detection step for detecting an irradiation position of predetermined instruction light irradiated to the subject from an image acquired by imaging, and an irradiation position detected by the detection step in the image acquired by imaging In accordance with the second setting step of setting the area corresponding to the second focus detection area and the focusing process based on the image information of the first focus detection area. a focusing process step performs the focusing processing based on the image information, after the irradiation position by the detecting step is detected once, in the detecting step A measurement step for measuring an elapsed time after the shooting position cannot be detected, and an imaging for performing an imaging operation for recording an image triggered by the elapsed time measured in the measurement step reaching a predetermined time And a control step .

Further, in the invention of claim 7, wherein, the computer having a digital camera having an autofocus function, a first setting means for setting a first focus detection area in the image acquired by the imaging by the imaging Detection means for detecting the irradiation position of the predetermined instruction light irradiated to the subject from the acquired image, the second focus corresponding to the irradiation position detected by the detection means on the image acquired by imaging second setting means for setting a detection area, the first in preference to the focusing processing based on the image information of the focus detection area, line Align the focusing processing based on the image information of the second focus detection area that control means, wherein after the irradiation position is detected once by the detecting means, measuring means for irradiating position by the detection means for measuring an elapsed time after no detectable As a trigger that the elapsed time measured by said measuring means reaches a predetermined time, and a focus control program for functioning as an imaging control means for causing the image pickup operation for the recording of the image.

  According to the present invention, it is possible to easily focus on a subject located at an arbitrary place in the photographing range.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a focus control system according to the present invention. As shown in the figure, the focus control system comprises a digital camera 1 and a laser pointer 51. First, the digital camera 1 will be described. The digital camera 1 of the present embodiment includes an AF function based on AE (automatic exposure) and a well-known contrast detection method, and a CPU 2 that controls the entire digital camera; It consists of the following parts.

  That is, the digital camera 1 includes a focus lens 3 supported by a drive mechanism (not shown) in the camera body, a focus motor 4 for moving the focus lens 3 in the optical axis direction, and a motor driver 5 for driving the focus motor 4. have. The motor driver 5 is connected to the CPU 2 via the bus 6, and focus adjustment is performed when the focus lens 3 moves in the optical axis direction based on a control signal from the CPU 2.

  On the other hand, the digital camera 1 of the present embodiment has a CCD 7 as an imaging means. The CCD 7 is driven by a vertical / horizontal driver 9 based on a timing signal generated by a timing generator (TG: Timing Generator) 8 in accordance with a command from the CPU 2, and photoelectrically converts an optical image of a subject formed through the focus lens 3. And it outputs to the analog signal processing part 10 as an imaging signal.

  The analog signal processing unit 10 includes a CDS circuit that removes noise included in the output signal of the CCD 7 by correlated double sampling, an A / D converter that converts the imaging signal from which noise has been removed to a digital signal, a gain adjustment amplifier, and the like. The digitally converted image signal is output to the image processing unit 11.

  The image processing unit 11 uses the SDRAM 12 as a working memory, and inputs an input digital image signal, that is, pixel interpolation from different color image data (Bayer data) according to the filter arrangement of the CCD 7, and RGB data for each pixel. Is generated and converted into YUV data comprising luminance (Y) and color difference (Cb, Cr) data. At that time, digital signal processing such as white balance adjustment by gain adjustment of Cb, Cr (R, B data) may be performed in accordance with a command from the CPU 2.

  The YUV data generated by the image processing unit 11 is sequentially stored in the SDRAM 12, converted into a video signal every time one frame of data (image data) is accumulated, and then the liquid crystal which is the display means of the present invention. It is displayed as a through image on the monitor (LCD) 13. When shooting in the recording mode, the image data (YUV data) temporarily stored in the SDRAM 12 is compressed by the CPU 2 and temporarily stored in the buffer area in the SDRAM 12, and finally is stored in a predetermined format such as JPEG. It is recorded in the external memory 14 as an image file. The external memory 14 is a memory card that can be attached to and detached from the camera body connected via a card interface (not shown).

  The image file recorded in the external memory 14 is read out and expanded by the CPU 2 in accordance with the user's selection operation in the reproduction mode, expanded on the SDRAM 12 as YUV data, and then displayed on the liquid crystal monitor 13.

  The flash memory 15 is a memory built in the camera body, and the flash memory 15 stores an image storage area in which a file of an image taken without the external memory 14 (memory card) is stored, A program area in which various programs necessary for the operation of the digital camera 1 are stored is secured. The program stored in the program area includes an AE control program and an AF control program (the focus control program of the present invention). By operating according to the AF control program, the CPU 2 detects the detection means of the present invention, It functions as a first setting means, a second setting means, a focusing processing means, a control means, an extracting means (including a measuring means), a display control means, and a photographing control means.

  The key input unit 16 includes operation keys such as a power key, a shutter key, a mode switch, a menu key, a display key, a control key, and a set key. The control keys are a set of (or integrated) direction keys that can be used to indicate the up, down, left, and right directions common to digital cameras, and are set items on the menu screen displayed on the liquid crystal monitor 13 when the menu key is pressed. Used to select settings. The set key is used to determine the selection state of setting items and setting contents. The key operation state in the key input unit 16 is sequentially scanned by the CPU 2, and when any operation key is operated by the user, the operation content is detected by the CPU 2.

  Next, the laser pointer 51 described above will be described. The laser pointer 51 is an irradiation unit according to the present invention that irradiates a specific subject desired by a user or a specific portion of an arbitrary subject when shooting, and is red and constant. It is configured to emit a laser beam that blinks at a cycle (several tens of times per second).

  Hereinafter, the operation of the digital camera 1 having the above-described configuration will be described. FIG. 2 is a flowchart showing the contents of the process according to the present invention which is executed by the CPU 2 when the AF function is set to ON in the recording mode.

  As shown in FIG. 2, the CPU 2 starts processing together with the setting of the recording mode, drives the CCD 7 at a predetermined frame rate, starts acquiring a through image, and starts displaying on the liquid crystal monitor 13 (step S1). As shown in FIG. 3A, a set of three AF frames 101 (multi-AF frames) is displayed on the display screen of the liquid crystal monitor 13 at the center of the screen where the through image 100 is being displayed (step S2).

  Subsequently, the CPU 2 checks whether or not the pointer priority mode is set at that time, that is, whether or not the pointer priority function is set on (step S3). In the pointer priority mode, as will be described later, when the user focuses on a specific subject desired by the AF function during shooting, an arbitrary position within the angle of view is set as a focus position by the light of the laser pointer 51. It is a mode that can be.

  Here, when the pointer priority mode is not set (NO in step S3), it is further confirmed whether or not there is any selection operation of any of the three AF frames 101 described above by the user (step S4). ). The AF frame 101 is selected by operating the above-described control key and set key by the user, for example, changing the AF frame 101 to be selected with the control key, and ending the selection with the set key (determining the AF frame 101). ).

  Until the AF frame 101 is selected (NO in steps S4 and S7), the presence / absence of the AF frame 101 selection operation is repeatedly confirmed. When the selection operation of the AF frame 101 is performed (YES in step S4), the AF area (first focus detection region in the present invention) in the image indicated by any of the selected AF frames 101 is targeted. That is, the focus lens position where the contrast value in the AF area is maximized is searched while the focus lens 3 is moved, and the AF operation is performed to move the focus lens 3 to the search position. Focusing is performed on a specific subject (or a specific part of a certain subject) overlapping (positioned) (step S5).

  Thereafter, until the shutter key is pressed (NO in step S6), the process returns to step S4, and when the AF frame 101 is selected again (step S), the focusing process is repeated each time (step S4). YES in S4, step S5). When the shutter key is pressed (YES in step S6), imaging processing such as an imaging operation for image recording by the CCD 7, compression of the captured image, and recording in the external memory 14 is performed at that time (step S17). Thus, one shooting operation is completed.

  On the other hand, if the confirmation result in step S3 described above is YES and the pointer priority mode described above is set, it is once confirmed whether or not the user has performed the selection operation of the AF frame 101 described above. If there is (YES in step S8), the process proceeds to step S5 at that time. That is, focusing is performed on a specific subject (or a specific portion of a certain subject) that overlaps (positions) the selected AF frame 101, and thereafter, the same processing as when the pointer priority mode is not set is performed. .

  On the other hand, if the AF frame 101 is not selected (step S8 NO), the RGB data of each frame generated by the image processing unit 11 and temporarily stored in the SDRAM 12 within a predetermined frame period (for example, 0.5 seconds). Only the R data is extracted, and the pixel value of each pixel is checked for each frame, and a light blinking region in which pixels whose pixel values change at a constant period is continuously arranged is detected (step S9). That is, the irradiation position of the light beam when the light beam (instruction light) of the laser pointer 51 is irradiated is detected.

  Then, at the beginning of the process, the light blinking area cannot be confirmed, and the light spot confirmation flag described later is OFF (both NO in steps S10 and S11), so the process directly returns to step S8. Thereafter, when the laser pointer 51 irradiates an arbitrary subject within the angle of view with a light beam, and the light blinking area can be confirmed accordingly (YES in step S10), the light blinking area is centered and each of the above-described light emitting areas is centered. An AF area (second focus detection area in the present invention) having the same size as the AF area indicated by the AF frame 101 is newly set, and focusing processing for the AF area is performed (step S12). Thereby, focusing on a specific subject (or a specific portion of a certain subject) irradiated with the light beam is performed.

  FIG. 3B is a diagram corresponding to FIG. 3A showing the light spot P appearing in the through image 100 when the subject within the angle of view is irradiated with the light beam of the laser pointer 51. An area indicated by a broken-line rectangle in the figure is the AF area 102 newly set in step S11. In addition, the same figure is the figure which expanded and showed the magnitude | size of the light spot P for convenience.

  Therefore, as shown in the figure, the user simply irradiates a specific portion of the desired subject (portion of the person's hand in the example of the figure), regardless of the three AF frames 101. An AF area can be set to the specific portion to focus.

  In addition, after focusing on a specific subject (or a specific portion of a certain subject) irradiated with the light beam as described above, the CPU 2 indicates a light spot indicating that irradiation with the light beam has started. After the confirmation flag is turned on (step S11), the process returns to step S8. Then, while the above-described light blinking region can be confirmed, that is, while the light beam irradiation is continued (YES in step S10), the focusing process in step S12 is repeated.

  Thereafter, when the light blinking region can no longer be confirmed, that is, when the light beam irradiation ends (NO in step S10), at that time, the timer is operated to start counting the elapsed time after the light beam irradiation ends ( NO in step S14, step S15). At the beginning of the count, since a predetermined time has not elapsed (NO in step S16), the process returns to step S8 and the above-described processing is repeated.

  Thereafter, the process of steps S8 to S16 is repeated until a predetermined time elapses after the irradiation of the light beam ends (NO in step S16), during which the user selects the AF frame 101. If (YES in step S8), the process immediately proceeds to step S5.

  Eventually, when a predetermined time elapses after the irradiation of the light beam ends (YES in step S16), it is used as a trigger to perform imaging processing, that is, an imaging operation for image recording by the CCD 7, compression of the captured image, and external memory 14 Is recorded (step S17). Thus, one shooting operation is completed.

  As described above, in the digital camera 1 according to the present embodiment, by setting the pointer priority mode at the time of shooting (the pointer priority function is set to on), the user can specify a specific subject desired or a specific portion of an arbitrary subject. In addition, even if a specific subject or the like is removed from any one of the AF frames 101 of the multi-AF frame only by performing a simple operation such as irradiating the light beam of the laser pointer 51, the specific subject For example, an AF area can be set for focusing. That is, it is possible to easily focus on a subject located at an arbitrary place in the shooting range.

  In addition, it is possible to immediately take a picture without operating the shutter key by simply ending the irradiation of the light beam. As a result, even an image with a composition in which the main subject is located outside the multi-AF frame can be easily captured and acquired.

  Even in the state in which the pointer priority mode is set, if the user selects any AF frame 101 of the multi AF frames, the above-described step SA9 can be performed without performing any operation for canceling the pointer priority mode. It is also possible to stop the subsequent processing and immediately shift to focusing using the AF frame 101. Therefore, usability is also good.

  Here, in the present embodiment, the light beam that is used by the user for instructing a specific subject or the like is used as blinking light, and a light blinking region in which pixels whose pixel values change at a constant cycle for each frame is continuously detected is detected. Since it is determined as the position designated by the user, the position instructed by the user can be determined with high accuracy. In addition, although the accuracy of determining the pointing position will be reduced, the light beam used for pointing to a fixed subject or the like does not necessarily have to be blinking light. Alternatively, the designated position may be determined by detecting a pixel having a pixel value with high luminance.

  Further, in this embodiment, the light blinking area is detected only from R data (pixel information) of the same color as the light beam that is used by the user to indicate a specific subject or the like. The processing load on the CPU 2 required for detection can be reduced, and the position instructed by the user can be determined with high accuracy. In this regard as well, although the processing load on the CPU 2 increases and the accuracy of determining the designated position decreases, the light blinking area may be detected from the image data of all color components.

  In the above description, the case where the present invention is applied to the digital camera 1 having a general configuration has been described. However, the present invention naturally includes a digital camera incorporated in another information device such as a mobile phone terminal. It is also applicable to.

1 is a block diagram of a focus control system according to the present invention. FIG. It is a flowchart which shows the operation | movement in the recording mode in the digital camera of the same system. 4A and 4B are examples of display screens during shooting standby, in which FIG. 5A shows a state in which multi AF is displayed, and FIG. 5B shows a state in which a specific subject is instructed by a laser pointer.

Explanation of symbols

1 Digital camera 2 CPU
3 Focus lens 4 Focus motor 5 Motor driver 7 CCD
11 Image processing unit 12 SDRAM
13 LCD Monitor 14 External Memory 15 Flash Memory 16 Key Input Unit 100 Through Image 101 AF Frame 102 AF Area P Light Spot

Claims (7)

In digital cameras with autofocus function,
Imaging means for capturing a subject image and acquiring the image;
First setting means for setting a first focus detection area in the image acquired by the imaging means;
Detection means for detecting an irradiation position of predetermined instruction light emitted to the subject from an image acquired by the imaging means;
Second setting means for setting a second focus detection area corresponding to the irradiation position detected by the detection means in the image acquired by the imaging means;
Control means for performing autofocus processing based on image information of the second focus detection region in preference to autofocus processing based on image information of the first focus detection region;
A measuring means for measuring an elapsed time after the irradiation position cannot be detected by the detection means after the irradiation position is once detected by the detection means;
An imaging control unit that causes the imaging unit to perform an imaging operation for recording a captured image triggered by an elapsed time measured by the measuring unit reaching a predetermined time is provided. Digital camera.   The digital camera according to claim 1, wherein the detection unit detects an irradiation position of the instruction light that is irradiated from the outside and blinks at a constant cycle from the image acquired by the imaging unit.   The detection unit includes an extraction unit that extracts pixel information of a color component similar to the color of the instruction light from an image acquired by the imaging unit, and the instruction light is based on the pixel information extracted by the extraction unit. The digital camera according to claim 1, wherein the irradiation position of the digital camera is detected. The first setting means sets a plurality of the first focus detection areas in the image acquired by the imaging means,
Display means for displaying an image acquired by the imaging means as a through image;
The display means further comprises display control means for displaying a plurality of focus frames respectively indicating the plurality of first focus detection areas in the image,
In response to the selection operation of any one of the plurality of focus frames displayed on the display unit by the display control unit, the control unit stops the irradiation position detection operation by the detection unit, and claims 1 to 3 digital camera according to any one, characterized in that to perform auto-focus processing based on the image information of the focus detection area corresponding to the selected focus frame by the selection operation. Irradiating means for irradiating a constant indication light Tokoro with respect subject,
A digital camera with an autofocus function,
Imaging means for capturing a subject image and acquiring the image;
First setting means for setting a first focus detection area in the image acquired by the imaging means;
Detecting means for detecting an irradiation position of the predetermined instruction light irradiated by the irradiation means from an image acquired by the imaging means;
Second setting means for setting a second focus detection area corresponding to the irradiation position detected by the detection means in the image acquired by the imaging means;
Control means for performing autofocus processing based on image information of the second focus detection region in preference to autofocus processing based on image information of the first focus detection region ;
A measuring means for measuring an elapsed time after the irradiation position cannot be detected by the detection means after the irradiation position is once detected by the detection means;
A digital image processing apparatus including: an imaging control unit that causes the imaging unit to perform an imaging operation for recording a captured image, triggered by an elapsed time measured by the measuring unit reaching a predetermined time; A focus control system characterized by comprising a camera. A focus control method for a digital camera having an autofocus function,
A first setting step for setting a first focus detection area in the captured image;
A detection step of detecting an irradiation position of predetermined instruction light irradiated to the subject from an image acquired by imaging ;
A second setting step of setting an area corresponding to the irradiation position detected in the detection step as a second focus detection area in the image acquired by imaging ;
A focusing processing step for performing focusing processing based on image information of the second focus detection area in preference to focusing processing based on image information of the first focus detection area ;
After the irradiation position is once detected in the detection step, a measurement step for measuring an elapsed time after the irradiation position cannot be detected in the detection step;
A focus control method comprising: an imaging control step for performing an imaging operation for recording an image with a trigger that the elapsed time measured in the measurement step has reached a predetermined time . A computer with a digital camera equipped with an autofocus function
First setting means for setting a first focus detection area in an image acquired by imaging ;
Detecting means for detecting an irradiation position of predetermined instruction light irradiated to the subject from an image acquired by imaging ;
Second setting means for setting a second focus detection area corresponding to the irradiation position detected by the detection means in an image acquired by imaging ;
The first focus detection area than the focusing processing based on the image information by priority, the second focus detection area control means causes I line focus processing based on the image information,
A measuring means for measuring an elapsed time after the irradiation position cannot be detected by the detection means after the irradiation position is once detected by the detection means;
An imaging control means for performing an imaging operation for recording an image, triggered by an elapsed time measured by the measuring means reaching a predetermined time;
Focus control program to function as

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