JP5361598B2 - Focus adjustment apparatus and method, and imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce ranging error in phase difference AF control by hybrid AF including contrast AF and phase difference AF. <P>SOLUTION: The focusing method includes the contrast AF and the phase difference AF to perform focusing on the basis of a phase difference between a pair of image signals obtained by photoelectric conversion by a pixel group for focus detection. When moving speed of a subject is equal to or above a threshold, focusing is performed by the phase difference AF. When the moving speed is under the threshold, focusing is performed by either of the contrast AF and the phase difference AF according to a predetermined condition. When the moving speed is equal to or above the threshold, a distance to the subject when acquiring the pair of image signals next time is predicted, and the area of the pixel group for acquiring the pair of image signals next time, in areas of the pixel groups for focus detection, is set according to the predicted distance. As the distance to the subject becomes shorter, a larger area is set. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a hybrid focus adjustment technique using a contrast method and a phase difference method.

  Conventionally, as automatic focus (AF) control of an imaging apparatus, an AF evaluation value is calculated using a contrast component extracted from a video signal obtained by photographing, and a focus lens position where the AF evaluation value is maximized is searched. A contrast method is known. In addition, a pair of light beams (optical images) from a subject that has passed through different exit pupil regions of the lens are imaged on a pair of line sensors, respectively, and based on the phase difference of the obtained video signals, the principle of triangulation is used. A phase difference method for obtaining a distance to a subject or a defocus amount is also known.

  Furthermore, a so-called hybrid AF method combining a contrast method and a phase difference method has also been proposed. In the hybrid AF method, first, the focus lens is moved to near the focus using the distance or defocus amount obtained by the phase difference method, and then the focus lens is moved by the contrast method. By controlling in this way, a focused state can be obtained at high speed with high accuracy (see, for example, Patent Documents 1 and 2).

  Further, in the phase difference type focus detection device, by selecting an area used for charge accumulation control and phase difference calculation from a pair of line sensors, the detectable distance or defocus amount can be adjusted. Possible focus detection devices have been proposed. (For example, see Patent Documents 3 and 4).

JP 2002-258147 A (page 13, FIG. 2, FIG. 3) Japanese Patent Laying-Open No. 2006-003428 (page 10, FIG. 4) JP 63-172206 A (FIG. 8) Japanese Patent Laying-Open No. 2006-220684 (FIG. 10)

  However, when performing phase difference AF control using a line sensor as described in Patent Documents 3 and 4 described above, if a large area is used, an extra background appears when the main subject is at a long distance. There is a problem that it becomes easy to miscalculate the phase difference. On the other hand, when the area is narrow, there is a problem that when the main subject is at a short distance, only a part of the subject is applied to the area of the line sensor, and it is easy to erroneously calculate the phase difference.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce erroneous distance measurement when phase difference type AF control is performed by a hybrid AF method using a contrast method and a phase difference method.

To achieve the above object, a focus detection contrast method rather based on the contrast of an image signal obtained from the image pickup means, pixel for focus detection and a pair of optical images which pass through different pupil areas of the imaging optical system focusing device of the present invention to perform a focus detection of the phase difference method rather based on a phase difference between a pair of image signals obtained by photoelectric conversion by the group, when the moving speed of the object is greater than or equal to the threshold, the position using the focus detection result of the phase difference method, when the moving speed is less than the threshold value, the focus adjusting the focus using the focus detection result of Zureka have contrast method and the phase difference scheme according to a preset condition When the moving speed is equal to or higher than the threshold value, the adjusting unit predicts the distance to the subject when the pair of image signals are acquired next time, and based on the predicted distance, the focus detection pixel group Of the following areas Said setting means for setting the area of the pixel groups to acquire a pair of image signals, from a plurality of images sequentially represented by successively obtained image signal from the imaging means, the object to be detected preset object, respectively and a detecting means, the setting means, the shorter the distance to the subject is not short, and sets a larger region, the moving speed is even greater than or equal to the threshold value, detected by the subject detecting means When the variation in the size of the subject is within a preset range and when the variation in the focus detection result by the contrast method is at least one of the preset range, the region Control not to change .

  According to the present invention, erroneous ranging can be reduced when phase difference AF control is performed by a hybrid AF method using a contrast method and a phase difference method.

1 is a block diagram showing a schematic configuration of an imaging apparatus according to a first embodiment of the present invention. The block diagram which shows the structure of AF signal processing circuit of FIG. The figure which shows the structural example of the phase difference detection sensor in 1st Embodiment. 5 is a flowchart of a focus adjustment process in the first embodiment. 6 is a flowchart for explaining a method for predicting a distance to a subject at the time of next distance measurement in the first embodiment. 6 is a flowchart showing processing for setting a distance measurement area at the time of next distance measurement according to the first embodiment. The figure which shows the example of a setting of the area of a sensor element row | line | column. 5 is a flowchart illustrating processing for obtaining a moving speed of a subject in the first embodiment. The flowchart which shows the process which judges the possibility of a stop in 1st Embodiment. The block diagram which shows schematic structure of the imaging device in the 2nd Embodiment of this invention. FIG. 11 is a diagram illustrating an example of a pixel array for focus detection in the image sensor 107 of FIG. 10. The figure which shows the structure of the pixel for focus detection in 2nd Embodiment. 10 is a flowchart illustrating processing for setting a distance measurement area at the time of next distance measurement according to the second embodiment. The figure which shows the example of a setting of the area of the pixel group for focus detection.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a block diagram showing a configuration of an imaging apparatus equipped with a focus control apparatus according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 102 denotes a zoom lens that can move in the optical axis direction and change the focal length of the photographing optical system. The zoom motor 103 is driven by the control of the zoom control circuit 104 and moves the zoom lens 102. Reference numeral 105 denotes a focus lens that moves in the optical axis direction to adjust the focus of the photographing optical system. The focus motor 106 is driven by the control of the focus control circuit 110 and moves the focus lens 105.

  Reference numeral 107 denotes an image sensor such as a CMOS sensor or a CCD, which photoelectrically converts a subject image formed on the image sensor 107 and outputs the obtained electric signal to the image signal processing circuit 108. The imaging signal processing circuit 108 processes the input electrical signal and outputs an image signal. The image signal output from the imaging signal processing circuit 108 is input to the AF signal processing circuit 109 and the memory 113. The AF signal processing circuit 109 generates an AF evaluation value (FV) indicating an in-focus state for performing AF control using a contrast method, and a signal (IFA) indicating the degree of focus, and outputs the generated signal to the focus control circuit 110.

  Here, the configuration of the AF signal processing circuit 109 and the processing to be performed will be described with reference to FIG.

  From the image signal from the imaging signal processing circuit 108, an image signal of a predetermined area in the screen is extracted by one or a plurality of distance measuring gates 201. FIG. 2 shows a case where there is one distance measuring gate.

  A high frequency component is extracted from the image signal extracted by the distance measuring gate 201 by a band pass filter (BPF) 202. Then, the detection unit (DET) 203 performs processing such as peak hold and integration to obtain an AF evaluation value FV and outputs it to the focus control circuit 110.

  The imaging signal that has passed through the distance measuring gate 201 is also sent to the bandpass filter 1 (BPF1) 204 and the bandpass filter 2 (BPF2) 207, and predetermined high-frequency components are extracted respectively. Note that the characteristics are selected so that the frequency extracted by BPF1 (204) is higher than the frequency extracted by BPF2 (207). The detectors (DET) 205 and 208 perform processing such as peak hold and integration, and the division unit 206 obtains BPF1 / BPF2, that is, the ratio of the frequency components of the imaging signal, to obtain a sum for each distance measurement area. Calculate the IFA.

  When there are a plurality of distance measuring gates 201, that is, when there are a plurality of distance measuring areas in the screen, a plurality of BPF, DET, and division units described above are provided, and the AF evaluation value FV and the degree of focus are provided. An IFA is also obtained for each distance measurement area.

  Returning to FIG. 1, the focus control circuit 110 automatically moves the focus lens 105 by driving the focus motor 106 based on the distance signal D, which will be described later, and the AF evaluation value FV and the in-focus level IFA described above. Focus (AF) control is performed. When there are a plurality of ranging areas in the screen, selection is made according to conditions from a plurality of sets of distance signals D, AF evaluation values FV, and in-focus levels IFA, and a focus operation is performed based on the selected signals. .

  On the other hand, the image signal stored in the memory 113 is compressed by the codec 114 and recorded on the recording medium 112. In parallel with the compression and recording processing, the image signal stored in the memory 113 is resized to an optimum size by the image processing circuit 116 and displayed on a monitor (not shown) with a face frame or the like superimposed. The photographed image is fed back to the photographer in real time.

  The face detection unit 115 (subject detection means) compares sequentially obtained image signals with a database image stored in advance by template matching or the like, so that the positions and sizes of the faces of a plurality of subjects, the number of faces, The reliability (probability) of the face is sequentially detected. Then, the obtained information is output to the CPU 111.

  The CPU 111 and each block are connected via a bus 117, and each block is controlled according to a program in the CPU 111.

  Reference numeral 100 denotes a phase difference detection sensor 100 having a configuration as shown in FIG. In FIG. 3, reference numerals 100a and 100b denote a pair of sensor element arrays in which photoelectric conversion elements are arranged side by side, each of which is divided into five areas L2, L1, C, R1, and R2, and the photoelectric conversion values of the selected divided areas are continuously displayed. Can be taken out. Two optical images of the same subject divided through a pupil division optical system for phase difference AF (hereinafter referred to as “phase difference optical system”) 101 that is an imaging optical system are sensor element arrays of the phase difference detection sensor 100. Images are formed on 100a and 100b, respectively. The phase difference detection sensor 100 detects a phase difference between the image signals of these two subject images obtained from the sensor element arrays 100a and 100b, calculates a distance signal D to the subject by triangulation, and a focus control circuit To 110. Instead of the distance signal D, the detected phase difference may be output.

  FIG. 4 is a flowchart of the focus adjustment process in the first embodiment controlled by the CPU 111. In the first embodiment, as the AF mode, the first AF mode and the second AF mode are provided. In the first AF mode, the contrast method is given priority, and in the second AF mode, the contrast mode is prioritized. The phase difference method shall be prioritized.

First, the AF mode indicating the AF control method is set to the first AF mode (S101). Next, based on the image signal obtained from the image sensor 107 through the image signal processing circuit 108, the AF signal processing circuit 109 obtains the AF evaluation value FV and the focus degree IFA, and the phase difference detection sensor 100 detects the distance signal. D is obtained (S102). Then, from the determined meth distance signal D at S102, it is determined whether the moving speed is slower than the rate at which the subject has been set in advance (threshold value) (S103), the process proceeds to late as (below the threshold) S104, Hayakere if (threshold Above) Go to S110.

  In S104, it is determined whether the contrast-type lens position calculated based on the AF evaluation value FV is different from the phase-difference type lens position calculated based on the distance signal D by a predetermined value or more. If it is different from the predetermined value, the process proceeds to S106, and if not different from the predetermined value, the process proceeds to S105. In S105, a contrast-type lens position is adopted, and in S106, a phase-difference type lens position is adopted. In S107, the focus lens 105 is driven to the lens position selected in S105 or S106, and the process returns to S101.

  As described above, when the moving speed of the subject is slower than a preset speed, the result of the contrast method is prioritized unless the result of the focus position by the phase difference method and the result of the focus position by the contrast method differ greatly.

  On the other hand, if the moving speed of the subject in S103 is equal to or higher than the preset speed, the AF mode variable is changed to the second AF mode (S110), and the phase difference method prioritized in the second AF mode is obtained. The focus lens 105 is driven to the in-focus position (S111).

  Next, the distance to the subject at the time of the next distance measurement is predicted based on the time-series distance signal D acquired so far (S112), and based on the predicted distance, L2 of the sensor element arrays 100a and 100b, An optimum area is set from L1, C, R1, and R2 (S113). Note that the distance prediction method performed in S112 will be described later in detail with reference to FIG. 5, and the optimum area setting method performed in S113 will be described later in detail with reference to FIG.

  In S115, as in S102, the AF signal processing circuit 109 obtains the AF evaluation value FV and the in-focus level IFA based on the image signal obtained from the imaging element 107 via the imaging signal processing circuit 108, and the phase difference. The detection sensor 100 obtains a distance signal D. Here, the phase difference detection sensor 100 detects the phase difference based on the signal obtained from the area set in S113, and obtains the distance signal D. Then, from the distance signal D obtained in S115, it is determined whether or not the moving speed of the subject is slower than a preset speed (threshold) (S116). If it is slow (less than the threshold), the process proceeds to S119. ) Go to S117.

  In S117, the focus lens 105 is driven to the in-focus position obtained by the phase difference method prioritized in the second AF mode, and in S118, it is determined whether or not the subject is suddenly stopped. Specifically, based on the phase difference detection result, the AF evaluation value and face detection based on the image signal obtained from the image sensor even though the moving speed of the subject is “threshold” or more When there is almost no change in size, it is determined that the subject may have stopped suddenly. In this case, the subject may stop suddenly, but the phase difference detection may be in an error state by measuring the distance including the portion other than the subject. When there is a possibility that the subject suddenly stops, the distance at the next distance measurement is predicted and the area of the phase difference detection sensor 100 is not switched, but the area selection is fixed and the distance is measured (S115). . Note that the determination method performed here will be described later with reference to FIG. If the stop has occurred, the process returns to S115, and if not, the process returns to S112 to repeat the above-described processing.

  On the other hand, in S119, a contrast-type focus degree IFA is acquired, and in S120, it is determined whether or not the acquired focus degree IFA has reached a preset target. If not reached, the process returns to S106, and if reached, the focus lens 105 is moved to the in-focus position obtained by the contrast method in Step S121, and the process returns to S101 to repeat the above-described processing.

  FIG. 5 is a flowchart for explaining a method of predicting the distance to the subject at the next distance measurement performed in S112 of FIG.

  The focus control circuit 110 converts the brightness from an aperture value that controls an iris (not shown) for exposure control. If it is bright, the value is large to reduce the iris, and if it is dark, the value is small to open the iris.

  Therefore, it is determined whether or not the aperture value for exposure control is less than F2.0 (S200). If it is less than F2.0, the next accumulation end time of the phase difference detection sensor 100, that is, the distance measurement time is predicted. After 1/10 second (S201), the process proceeds to S205. On the other hand, if it is F2.0 or more, it is determined whether or not the aperture value for exposure control is less than F2.8 (S202). Then, the distance measurement time is predicted to be 1/30 seconds later (S203), and the process proceeds to S205. On the other hand, if it is F2.8 or more, the next AF sensor accumulation end time, that is, the distance measurement time is predicted 1/60 seconds later (S204), and the process proceeds to S205. In S205, the distance to the subject at the next distance measurement is predicted from the current moving speed and the next accumulation end prediction time, and the process is terminated.

  FIG. 6 is a flowchart for explaining the area setting process of the sensor element arrays 100a and 100b performed in S113 of FIG. Here, the focus control circuit 110 selects the areas of the sensor element arrays 100a and 100b from the zoom control value and the predicted distance to the subject at the next distance measurement.

  If the zoom magnification is low, the distance measurement area is widened. If the subject distance is short, the distance measurement area is narrowed. Therefore, it is determined whether or not the zoom magnification is less than 3 times (S300). If it is less than 3 times, the process proceeds to S301, and if it is 3 times or more, the process proceeds to S306.

  In S301, it is determined whether the predicted distance to the subject at the next distance measurement is less than 5 m. If it is less than 5 m, the areas of the sensor element arrays 100a and 100b to be used next time are L2, L1, C, R1, and R2 in FIG. 3 (S302), and if it is 5 m or more, they are L1, C, and R1 (S303). ).

  On the other hand, when the zoom magnification is 3 times or more (NO in S300), it is determined whether or not the zoom magnification is less than 5 times (S306). If it is less than 5 times, the predicted distance to the subject at the next distance measurement is determined. Is less than 3 m (S307). If the distance is less than 3 m, the areas of the sensor element arrays 100a and 100b to be used next time are L2, L1, C, R1, and R2 in FIG. 3 (S308). If the distance is 3 m or more, whether the predicted distance is less than 5 m. Is determined (S309). If it is less than 5 m, the areas of the sensor element arrays 100a and 100b to be used next time are set to L1, C, and R1 in FIG. 3 (S310), and if 5 m or more, they are set to C in FIG. 3 (S311).

  If the zoom magnification is 5 times or more (NO in S306), it is determined whether or not the predicted distance to the subject at the next distance measurement is less than 3 m (S312). If it is less than 3 m, the areas of the sensor element arrays 100a and 100b to be used next time are set to L1, C, and R1 in FIG. 3 (S313), and if it is 3 m or more, it is set to C in FIG.

  FIG. 7 is a diagram illustrating an operation example of setting the areas of the sensor element arrays 100a and 100b described with reference to FIG. 6 described above. In the example of FIG. 7, the zoom magnification is 3 times or more and less than 5 times (YES in S306).

  7A shows the case where the distance to the subject is 5 m or more (NO in S309), and the area set in this case is C in FIG. 3 (S311). (B) shows a case where the distance to the subject is 3 m or more and less than 5 m (YES in S309), and the areas set in this case are L1, C, and R1 in FIG. 3 (S310). In (c), since the distance to the subject is less than 3 m (YES in S312), the areas set in this case are L2, L1, C, R1, and R2.

  FIG. 8 is a flowchart showing the process for obtaining the distance signal D and the process for obtaining the moving speed of the subject performed in S102 and S115 of FIG.

  First, line sensor values obtained from the sensor element arrays 100a and 100b of the phase difference detection sensor 100 are A / D converted (S401), and it is determined whether or not A / D conversion has been performed a predetermined number of times (S402). If it has not been performed a predetermined number of times, the process returns to S401, and if it has been performed, the process proceeds to S403. In S403, the phase difference between the line sensor value (A image) obtained from the sensor element array 100a and the line sensor value (B image) obtained from the sensor element array 100b is detected, and triangulation is performed from the obtained phase difference. The distance is calculated using the principle (S404). In S405, the moving speed is calculated from the time-series change in the distance obtained in S404 so far, and the process is terminated.

  FIG. 9 is a flowchart showing a process for determining the possibility of stopping the subject performed in S118 of FIG.

  In S500, it is determined whether or not the AF evaluation value FV has fluctuated more than a predetermined value. If fluctuated, the process proceeds to S502, and if not fluctuated, the process proceeds to S501. In S501, it is determined whether or not the variation in the size of the face detected by the face detection unit 115 is within a preset range, and if it varies, the process proceeds to S502. In S502, it is determined that there is no possibility that the subject has suddenly stopped, and the process ends. On the other hand, if there is no change, the process proceeds to S503, and the process is terminated because there is a possibility that the subject has suddenly stopped.

  As described above, when at least one of the AF evaluation value FV and the variation amount of the face size is equal to or larger than the predetermined value, there is no possibility that the subject has suddenly stopped, and the variation amount is less than the predetermined value. Determines that the subject may have stopped suddenly. This is because, although the subject may have stopped suddenly, the phase difference detection may measure the distance including the portion other than the subject and enter an error state. When there is a possibility that the subject suddenly stops, the distance at the next distance measurement is predicted and the area of the phase difference detection sensor 100 is not switched, but the area selection is fixed and the distance is measured. It is possible to prevent distance measurement from entering an error state.

  As described above, according to the first embodiment, during the second AF mode, the distance from the current distance measurement result to the main subject at the next distance measurement is predicted, and the phase difference detection sensor 100 to be used is used. The area of the sensor element rows 100a and 100b is selected. As a result, erroneous distance measurement can be made difficult to occur.

  Also, when the AF evaluation value and the detected face size variation are below a predetermined value, the area is not changed even if the current result is an erroneous distance measurement. Incorrect distance measurement is less likely to occur.

<Second Embodiment>
Next, a second embodiment of the present invention will be described.

  FIG. 10 is a block diagram showing a configuration of an imaging apparatus equipped with a focus control apparatus according to the second embodiment of the present invention. 10, the same reference numerals are assigned to the same components as those in FIG. 1, and the description thereof is omitted. First, the configuration shown in FIG. 10 differs from the configuration shown in FIG. 1 in that the phase difference detection sensor 100 and the phase difference optical system 101 are not provided. Further, it is possible to output signals S1 and S2 having a phase difference from the image sensor 107, and the image signal processing circuit 208 calculates the distance signal D and transmits it to the focus control circuit 110.

  FIG. 11 is a diagram illustrating an example of a pixel array for focus detection in the image sensor 107. In FIG. 11, R, G, and B correspond to the colors, red, green, and blue of the color filter formed in each pixel portion, respectively, and form a Bayer array with 4 pixels of 2 rows × 2 columns as one cycle. Yes. Then, pixels S1 and S2 that output signals S1 and S2 are arranged side by side in some rows, and these pixels S1 and S2 function as focus detection pixels.

  Here, the configuration of the pixel S1 will be described with reference to FIG. 12A is a view of the pixel S1 as viewed from above, and FIG. 12B is a cross-sectional view taken along line A-A ′ in FIG. In the pixel S1, a smoothing layer 124, a light shielding layer 123, and a smoothing layer 122 are sequentially stacked on the photoelectric conversion layer 125, and a microlens 121 is provided thereon. A filter layer is not provided. Further, the light shielding layer 123 is formed with an opening that is deviated (eccentric) to one side from the center of the photoelectric conversion area of the pixel. Note that the configuration of the pixel S2 is obtained by inverting the left and right of the configuration shown in FIG.

  Therefore, the pixels S1 and S2 receive the optical images respectively passing through different exit pupil regions of the imaging optical system by the optical power of the microlens 121 and the opening of the light shielding layer 123.

  A plurality of pixels S1 arranged in the row direction (hereinafter referred to as “focus detection pixel group S1”) and a plurality of pixels S2 arranged in the row direction (hereinafter referred to as “focus detection pixel group S2”). The signal is taken out. Then, an image signal obtained by connecting the image signals from the focus detection pixel group S1 and an image signal obtained by connecting the image signals of the focus detection pixel group S2 are formed. From the pair of image signals formed in this way, it is possible to observe a phase difference accompanying defocusing of the photographing optical system. The imaging signal processing circuit 208 detects the phase difference between the image signals, obtains a distance signal D to the subject based on the detected phase difference, and outputs the distance signal D to the focus control circuit 110. Since the distance measurement using the image sensor 107 is a through-the-lens (TTL) method, erroneous distance measurement due to parallax does not occur unlike the external phase difference detection sensor 100 shown in FIG.

  In the second embodiment, the focus adjustment process is basically performed by the same control as described with reference to FIG. 4, but the area setting process of the focus detection pixel groups S1 and S2 performed in step S113. Is different from the processing described with reference to FIG. Hereinafter, the area setting process in the second embodiment will be described with reference to FIG. The process shown in FIG. 13 is controlled by the CPU 111, and the focus control circuit 110 selects the areas of the sensor element arrays 100a and 100b from the predicted distance to the subject at the next distance measurement.

  In step S601, it is determined whether the predicted distance to the subject at the next distance measurement predicted in step S112 in FIG. 4 is less than 3 m. If it is less than 3 m, the area to be used is increased in the focus detection pixel groups S1 and S2 next time (S602), and the process ends. If it is 3 m or more, it is determined whether or not the predicted distance to the subject at the next distance measurement is less than 5 m (S603). If it is less than 5 m, the next area to be used from the focus detection pixel groups S1 and S2 is set to the middle (S604), and if it is 5 m or more, the area to be used from the focus detection pixel groups S1 and S2 is set to be small (S605). ) Finish the process.

  FIG. 14 is a conceptual diagram showing an example of selection of the regions of the focus detection pixel groups S1 and S2 shown in FIG. 11 described above, and assumes a case where a plurality of focus detection pixel groups S1 and S2 are configured without a screen. doing. In FIG. 14, (a) shows a case where the distance to the subject is 5 m or more (NO in S603), and the area set in this case is small (S605). (B) shows a case where the distance to the subject is 3 m or more and less than 5 m (YES in S603), and the area set in this case is the middle (S604). (C) has shown the case where a position is less than 3 m (it is YES at S601), and the area | region set in this case becomes large (S602).

  As described above, according to the second embodiment, during the second AF mode, the distance from the current distance measurement result to the main subject at the next distance measurement is predicted, and the focus detection pixels in the image sensor 107 are detected. Regions for detection in the groups S1 and S2 are set. As a result, erroneous distance measurement can be made difficult to occur.

  In the above-described embodiment, the face detection unit is shown as the subject detection unit. However, the present invention is not limited to this. For example, it may not be a face as long as it detects a subject (object). For example, it may be possible to cut out and detect a subject image from the background. At this time, the subject may be other than a person.

Claims (5)

And focus detection contrast method rather based on the contrast of an image signal obtained from the imaging means, obtained by photoelectrically converting, by a pair of pixel groups for focus detecting optical images which pass through different pupil areas of the imaging optical system and a focus detection and focusing device that performs the based rather phase difference method the phase difference between a pair of image signals,
When the moving speed of the object is greater than or equal to the threshold, using the focus detection result of the phase difference method, wherein when the moving speed is less than the threshold value, the deviation have contrast method and the phase difference scheme according to a preset condition a focus adjustment unit that performs focus adjustment by using one of the focus detection result,
When the moving speed is equal to or higher than the threshold value, the distance to the subject when the pair of image signals is acquired next time is predicted, and based on the predicted distance, Setting means for setting a region of the pixel group for acquiring the pair of image signals next time ;
Subject detection means for respectively detecting preset subjects from a plurality of images sequentially represented by image signals sequentially obtained from the imaging means ;
The setting means, the shorter the distance to the subject is not short, and sets a larger area, the even moving speed is equal to or more than the threshold, the variation in the size of the object detected by the object detecting means in advance Control is performed so as not to change the region when the range is within a set range and when the focus detection result variation by the contrast method is at least one of the range within a preset range. A focusing device characterized by that. Further comprising an acquisition means for acquiring the zoom magnification of the zoom lens;
The focus adjustment apparatus according to claim 1, wherein the setting unit further sets a wider area as the acquired zoom magnification is higher. Predicting means for predicting a time for acquiring the pair of image signals next based on brightness of the image signals;
Distance measuring means for obtaining a distance to the subject based on the phase difference;
The setting means, time predicted by said predicting means, wherein based on the variation of the distances determined by the distance measuring means, to claim 1 or 2, characterized in that predicting the distance to the object The focusing device as described. Imaging apparatus characterized by mounting the focusing device according to any one of claims 1 to 3. And focus detection contrast method rather based on the contrast of an image signal obtained from the imaging means, obtained by photoelectrically converting, by a pair of pixel groups for focus detecting optical images which pass through different pupil areas of the imaging optical system and a focus detection and the focus adjustment method of performing the based rather phase difference method the phase difference between a pair of image signals,
The focusing means, when the moving speed of the object is greater than or equal to the threshold, using the focus detection result of the phase difference method, wherein when the moving speed is less than the threshold value, the contrast method and position in accordance with a preset condition a focusing step of performing focus adjustment using the focus detection result of Zureka have retardation scheme,
When the setting means predicts the distance to the subject when the pair of image signals are acquired next time when the moving speed is equal to or higher than the threshold,
A setting step in which the setting means sets a region of the pixel group for acquiring the pair of image signals next time, out of the region of the pixel group for focus detection, based on the predicted distance ;
A subject detection unit for detecting each preset subject from a plurality of images sequentially represented by image signals sequentially obtained from the imaging unit ;
In the setting step, the smaller the distance to the subject is not short, and sets a larger area, the even moving speed is equal to or more than the threshold, the variation in the size of the object detected by the object detecting means in advance The region is not changed when it is within a set range and when at least one of a change in focus detection result by the contrast method is within a preset range. Focus adjustment method.

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