JP2010032575A - Imaging apparatus, imaging method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an imaging apparatus which facilitates focusing on an AF area which is frequently used by a photographer, in multipoint AF. <P>SOLUTION: The imaging apparatus includes: a storing means for storing the number of times that each of a plurality of AF areas set within an imaging angle of view is used for focusing processing, as a history, and a selection means (24) for selecting the AF area used frequently times as an AF area to be focused based on the history stored in the storing means during focusing processing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, an imaging method, and a program, and more particularly, to an imaging apparatus, an imaging method, and a program having a multipoint AF function.

  Multipoint AF is one of automatic focus (AF) techniques in an imaging apparatus such as a digital camera. In the initial AF, control was performed so as to focus on (focus on) an image in one small rectangular frame (hereinafter referred to as an AF area) provided almost at the center of the shooting angle of view. Depending on the shooting composition, the subject may be located outside the AF area. In such a case, the AF area is focused on the subject and the focus is locked (the shutter button is pressed halfway). After returning to the desired composition, a troublesome operation of shutter release (full pressing of the shutter button) is required. Multipoint AF is an improvement over the disadvantages of such initial AF. In other words, even if the subject to be focused is out of the center of the shooting angle of view, the shutter button is half-pressed (AF) to full-pressed (AF) with the desired composition without going through the above troublesome procedure ( (Continuous imaging) can be performed.

  FIG. 11 is a diagram showing an AF area of multipoint AF. In this figure, a finder screen (or a monitor screen of a digital camera) 1 displays a plurality of rectangular frames, here, for example, 3 × 3 = 9 rectangular frame groups 2.

  Each rectangular frame is an independent AF area. For convenience of explanation, each rectangular frame is identified by assigning a sequential number from the upper left to the lower right. That is, the upper left rectangular frame is the first AF area, the upper middle rectangular frame is the second AF area, the upper right rectangular frame is the third AF area, the middle left rectangular frame is the fourth AF area, and the middle middle rectangular frame is the fifth AF. Area, the right middle rectangular frame is the sixth AF area, the lower left rectangular frame is the seventh AF area, the lower middle rectangular frame is the eighth AF area, the lower right rectangular frame is the ninth AF area, and if necessary, Each will be referred to by the abbreviation “number + E”. For example, when the first AF area is abbreviated as “1E”, the second AF area is abbreviated as “2E”,..., And when the ninth AF area is abbreviated as “9E”.

  FIGS. 12A and 12B are operation conceptual diagrams of multipoint AF. FIG. 12A shows the case of a single subject, and FIG. 12B shows the case of a plurality of subjects. If only a single subject 3 is shown on the finder screen 1 as shown in (a), the AF area (6E in this figure) at the position of the subject 3 is in focus, so the shutter button is fully pressed as it is. It doesn't matter. However, as shown in (b), when a plurality of subjects 4 and 5 are located far and away, the AF area (5E in this figure) of the far subject 4 may be in focus, or It may focus on the AF area of the subject 5 (6E in this figure). Therefore, in the situation as shown in (b), some contrivance is required for selecting the AF area.

Therefore, Patent Document 1 below describes a technique for acquiring an AF evaluation value based on a contrast value for each pixel of a captured subject image and determining an in-focus position of the optical system based on the acquired AF evaluation value (same as above). (See claim 1 of the literature). If this technology is referred to as the prior art, in this prior art, AF area selection is performed based on the AF evaluation value. For example, in the case shown in FIG. Focus on the area.
JP 2004-029105 A

  However, in the prior art, since the AF area is selected based on the AF evaluation value, the following inconvenience may occur. That is, in many shooting scenes, a photographer often takes pictures with his / her favorite composition, and the favorite composition tends to place a subject to be focused at a fixed position. However, in the prior art, in order to focus on a subject with a high AF evaluation value (contrast value), for example, the photographer prefers a composition in which the subject is arranged at the center of the shooting angle of view, and the subject at the center of the shooting angle of view is selected. Even if it is desired to focus, if there is a subject with a higher AF evaluation value in front of the subject, there is a disadvantage that the subject in front is in focus, contrary to the intention of the photographer. .

  Therefore, an object of the present invention is to provide an imaging apparatus, an imaging method, and a program that can easily focus on an AF area frequently used by a photographer in multipoint AF.

According to the first aspect of the present invention, for each of a plurality of AF areas set within a shooting angle of view, data representing the number of times used for focusing processing is stored as a history, and during the focusing processing, the storage is performed. An image pickup apparatus comprising: a selection unit that selects an AF area that is frequently used as an AF area to be focused based on a history stored in the unit.
According to the second aspect of the present invention, in the focusing process, an acquisition unit that acquires an AF evaluation value curve for each of the plurality of AF areas, and a gradient of each AF evaluation value curve acquired by the acquisition unit, First determination means for determining whether or not there is an AF area having a maximum size within a shooting angle of view, and an AF area having a size within a predetermined threshold from the maximum size; In addition, the selection unit selects an AF area to be focused from the existing AF areas according to the history stored in the storage unit when it is determined by the first determination unit The imaging apparatus according to claim 1, wherein:
According to a third aspect of the present invention, when the selection unit determines that the first determination unit is present, the selection unit selects an AF area that is used more frequently in the history stored in the storage unit. The imaging apparatus according to claim 2.
According to a fourth aspect of the present invention, when it is determined by the first determination means that the AF area having the maximum size is used for focusing processing and the maximum size is within a predetermined threshold. Further comprising a second determination means for determining whether or not a difference from the number of times an AF area having a size of is used for the focusing process is greater than or equal to a predetermined value. The imaging apparatus according to claim 2, wherein when it is determined that there is a predetermined number or more, the AF area that is used more frequently is selected.
The invention according to claim 5 further comprises changing means for changing the magnitude of the gradient of each AF evaluation value curve acquired by the acquiring means based on the history stored in the storing means, 3. The imaging apparatus according to claim 2, wherein the selection unit selects the AF area based on the magnitude of the gradient changed by the changing unit.
The invention according to claim 6 is the imaging apparatus according to claim 2, wherein the AF evaluation value is a change amount of contrast.
According to the seventh aspect of the present invention, an imaging unit that captures an image in the AF area selected by the selection unit, and the number of times of use corresponding to the selected AF area increases when the imaging unit captures an image. The imaging apparatus according to claim 1, further comprising a storage control unit that controls the storage unit.
The invention according to claim 8 further includes third determination means for determining the vertical and horizontal directions of the imaging apparatus during the focusing process, wherein the storage control means is arranged in the vertical and horizontal directions determined by the third determination means. 8. The image pickup apparatus according to claim 7, wherein control is performed so as to increase the number of times used.
The invention according to claim 9 further includes shooting mode setting means for selectively setting a plurality of shooting modes with different shooting conditions, and the storage control means controls to increase the number of times used for each shooting mode. The imaging apparatus according to claim 7, wherein:
According to a tenth aspect of the present invention, a detection step for detecting an instruction for focusing processing, and when an instruction for the focusing processing is detected in this detection step, the focusing processing is performed for each of a plurality of AF areas previously stored in the memory. Referencing the data representing the number of times used, a focusing step for performing the focusing process, a determining step for determining whether or not the shooting process has been performed in the focused process at the focusing step, and this determination If it is determined that the photographing process is performed in the step, the image capturing method includes a storage control step and means for controlling the memory so as to increase the number of times of use corresponding to the AF area.
According to the eleventh aspect of the present invention, when a computer included in the imaging apparatus detects a focus processing instruction by the detection unit, and the detection unit detects the focus processing instruction, each of a plurality of AF areas stored in the memory in advance is detected. With reference to data representing the number of times used for the focusing process, focusing means for performing the focusing process, determination means for determining whether or not the shooting process is performed in a state in which the focusing process is performed by the focusing means, When it is determined that the photographing process has been performed by the determination unit, the program functions as a storage control unit that controls the memory so as to increase the number of times of use corresponding to the AF area.

  According to the present invention, it is possible to provide an imaging apparatus, an imaging method, and a program that can easily focus on an AF area frequently used by a photographer in multipoint AF.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking application to a digital camera with a multipoint AF function as an example.

  FIG. 1 is a conceptual configuration diagram of a digital camera. In this figure, the digital camera 10 includes an optical system 11 including an AF mechanism 11a (a mechanism for mechanically changing the focal length of the optical lens group 11b), and a subject T captured via the optical system 11. An image pickup unit 12 including a two-dimensional image pickup device such as a CCD or CMOS that converts an image into a two-dimensional image signal and outputs the image, and a required image processing (gamma correction, etc.) on the image signal output from the image pickup unit 12 An image processing unit 13 for performing the above, a focus driving unit 14 for driving the AF mechanism 11a of the optical system 11, and various buttons (a mode switching button 15a between a photographing operation and a reproducing operation, a menu button 15b, a cursor key 15c, and a shutter button) 15d etc.), a flash unit 16, a display unit 17 comprising a liquid crystal display, etc., and a fixed or removable large capacity An external I / F (interface) 20 that mediates data input / output between a storage unit 18 including a storage device, an external device 19 such as a personal computer, a power source unit 21 including a battery, and a control unit 22 Prepare.

  The control unit 22 includes a computer (hereinafter referred to as CPU) 22a, a nonvolatile memory (hereinafter referred to as ROM) 22b, a volatile memory (hereinafter referred to as RAM) 22c, and a rewritable nonvolatile memory (hereinafter referred to as PROM) 22d. The control program stored in advance in the ROM 22b and the data written in advance or arbitrarily in the PROM 22d are loaded into the RAM 22c and executed by the CPU 22a, that is, the shooting function and the playback function of the digital camera 10 by the program control method. However, the present invention is not limited to this, and it is needless to say that all or part of the functions may be realized by hard logic.

The illustrated digital camera 10 operates as follows.
First, an outline of the shooting operation and the playback operation will be given. When the mode switching button of the operation unit 15 is in the “shooting” position, the digital camera 10 operates in the shooting mode. In this shooting mode, an image signal output periodically (several tens of frames per second) from the imaging unit 12 is output to the display unit 17 via the image processing unit 13 and the control unit 22, and is used as a through image for composition confirmation. Displayed continuously. Then, the photographer adjusts the shooting direction and the angle of view of the imaging unit 12 so that the desired composition is obtained while viewing the through image, and when the desired composition is obtained, the shutter button 15d is half-pressed to perform the focusing process. Is detected, multipoint AF is performed. If the photographer selects the desired AF area and proceeds to the release (shooting operation) as it is, the shooting process is performed in the AF area. On the other hand, if the AF area is not selected, the multipoint AF is performed. The operation is continued until a desired AF area is selected. Detailed description of multipoint AF will be described later.

  When an AF area is selected and a release operation by the photographer is detected, an imaging process including AF (automatic focus) and AE (automatic exposure) is executed in response to the release operation, and the imaging unit 12 is operated. A high-quality image signal is taken out from. This image signal is sent to the storage unit 18 via the image processing unit 13 and the control unit 22, and is recorded and saved in the storage unit 18 as a captured image. The captured image may be a raw image (also referred to as a RAW image) corresponding to a high-quality image signal extracted from the imaging unit 12, but the raw image has a large size and a storage capacity of the storage unit 18. Therefore, for example, it is desirable to record an image compressed using a general-purpose compression technique such as JPEG (Joint Photographic Experts Group) as a photographed image. In the present embodiment, it is assumed to follow. That is, the control unit 22 performs JPEG compression conversion on the high-quality image signal captured in response to the release operation, and records and saves the JPEG converted image in the storage unit 18 as a captured image. Needless to say, “JPEG” is merely an example of a general-purpose compression technique, and other compression techniques may be used.

  On the other hand, when the mode switching button of the operation unit 15 is in the “playback” position, the digital camera 10 operates in the playback mode. In this playback mode, several playback styles can be selected. In the first style, the most recently captured image is read from the storage unit 18, and after JPEG decompression processing, the image is enlarged and displayed on the display unit 17, and the second style is a captured image. A reduced image (a thumbnail image, which is generated at the time of JPEG conversion and is incorporated into the JPEG converted image) is read from the storage unit 18 and displayed on the display unit 17. A list is displayed, an image desired to be reproduced is selected from the list, and the original image is read from the storage unit 18 and enlarged and displayed on the display unit 17.

  Next, the multipoint AF in the present embodiment will be described in detail. As explained at the beginning, multipoint AF is one of AF techniques in an imaging apparatus such as a digital camera, and selects a plurality of AF areas within a shooting angle of view, and performs AF using the selected AF areas. It is a technique to be executed. The AF technology in multipoint AF is typically “phase difference detection AF” or “contrast AF”, and the former is often used for a single-lens reflex camera and the latter is often used for a compact digital camera. All of the AF techniques are basically common in that the focusing operation is performed by selectively using a plurality of AF areas set within the shooting angle of view. Specifically, the phase difference detection AF emits a light beam from a camera, receives reflected light from a subject with a semiconductor position detection element called PSD, and based on the light receiving position, the distance to the subject (that is, focal length). ). Contrast AF checks the contrast (brightness / darkness difference) of each AF area in the image signal output from the imaging unit 12 while moving the AF mechanism 11a of the optical system 11, and determines the AF area where the highest contrast is obtained. This is a technique for selecting as a focusing area. In the present invention, any of these AF techniques may be used, or an AF technique other than the above two AF techniques (phase difference detection AF, contrast AF) may be used. In short, multi-point AF may be used. However, for convenience of explanation, in the present embodiment, description will be made using contrast AF as an example.

  FIG. 2 is a conceptual functional block diagram of AF control in the present embodiment. In this figure, the control unit 22 includes several functional blocks realized by a program control method. That is, a “half-press” operation on the shutter button 15d of the operation unit 15 is used as an instruction for focusing processing, and a “full-press” operation is detected as an instruction for shooting processing, and “ A contrast AF control unit 24 that executes contrast AF control in response to a “half-press” operation, an imaging control unit 25 that executes imaging control in response to a “full press” operation of the shutter button 15d, and an execution of the imaging control. For example, it includes an image compression unit 26 that JPEG compresses the captured image signal and stores it in the storage unit 18.

  Here, the contrast AF control unit 24 applies a plurality of AF areas (here, 3 × 3 = 9 AFs shown in FIG. 11 for convenience of explanation) to the through image captured via the image processing unit 13. Area, that is, 1E, 2E, 3E,..., 9E), and partial images included in the respective AF areas are extracted, and the contrast (difference between light and dark) of each extracted image is extracted. To compare.

  FIG. 3 is a conceptual diagram of contrast AF. In this figure, three of the nine AF areas (4E, 6E, 7E) are shown as representative examples. In the figure, the horizontal axis is the focus lens address, and the vertical axis is the AF evaluation value. “Focus lens address” is an index representing the movement position of the focus lens included in the optical lens group 11b. In the illustrated example, the position of the focus lens can be freely changed between address 0 and address 100 by the function of the AF mechanism 11a. The “AF evaluation value” is an index indicating whether or not the subject is in focus. In contrast AF, the amount of contrast change is used as an evaluation value. Specifically, the contrast change amount is calculated while moving the focus lens, and the higher the change amount, the higher the evaluation value is given. Then, a pseudo curve of the calculated AF evaluation value is acquired, a curve having the largest gradient (slope) is selected, and the focus lens is moved to a position where the AF evaluation value of the selected curve is maximized.

  Now, referring to FIG. 3, in this example, a clear peak is observed in the 4E AF evaluation value curve at the position of the focus address 40, and a slight peak is also observed in the 7E AF evaluation value curve at the same position. The peak is observed. Furthermore, a clear peak in the 6E AF evaluation value curve is observed at the position of the focus address 80. Actually, AF evaluation value curves as shown in FIG. 3 are calculated for all AF areas, but only 4E, 6E, and 7E are shown for explanation.

  FIG. 4 is a diagram showing AF area selection. (A) is a selection state of 4E and 7E, (b) is a selection state diagram of 6E, and the selected AF area is indicated by a thick frame. Here, in (a), both 4E and 7E are in the selected state because the peak in the 4E AF evaluation value curve and the peak in the 7E AF evaluation value curve have substantially the same focus lens address. 4E is actually selected, but 7E is also in focus, and the selected state shown in FIG. 4A is obtained.

  In either state (a) or (b), there is no inconvenience as long as the photographer's intention is selected. For example, the photographer's intention is in (a) and the actual selection is (b). If, on the contrary, the photographer's intention is in (b) and the actual selection is as in (a), the shooting will fail due to the defocusing of the subject of interest. Invite.

  In view of such inconveniences, in the present embodiment, the AF area usage history is recorded, and when the AF area is selected, the history is taken into consideration, thereby making it easier to focus on the AF area intended by the photographer. It is.

  FIG. 5 is a conceptual diagram of an AF area use history data table. The usage history data table 27 is stored in, for example, the PROM 22d of the control unit 22, and is composed of an AF area number field 27a and a history data field 27b. In the AF area number field 27a, the AF area number (1E, 2E, 3E,..., 9E) is stored, and in the history data field 27b, data relating to the usage history of each AF area (in this case, used) Count) is stored. For example, in the illustrated example, 1E → 4 times, 2E → 16 times, 3E → 5 times, 4E → 17 times, 5E → 22 times, 6E → 12 times, 7E → 5 times, 8E → 13 times, 9E → 6 History data for convenience of explanation of times is stored.

  FIG. 6 is a diagram in which history data stored in the use history data table 27 is applied to each AF area. In this example, the center AF area (5E) is used the most 22 times, and the four AF areas (2E, 4E, 6E, 8E) located on the top, bottom, left and right are used 16 times, 17 times, The number of uses of the four AF areas (1E, 3E, 7E, 9E) located at the four corners is 12, 5, 5, and 6 times, respectively. Therefore, from this example, it can be said that the photographer often takes a so-called “Hinomaru composition photograph” in which a subject is placed at the center of the composition and focused. It is considered that a photographer having such a tendency often takes the same “photo of the Hinomaru composition” in the subsequent shooting. Therefore, when selecting the AF area in the subsequent shooting, the center AF area is selected. The degree of selection of (5E) should be increased. By doing so, it is possible to perform an appropriate AF area selection according to the photographer's intention, thereby increasing the focus tendency on the subject of interest.

  FIG. 7 is a diagram illustrating an operation flow of a shooting mode processing program including an AF area selection process in consideration of an AF area use history. This program is executed by the CPU 22 a of the control unit 22. In this program, first, when a “half-press” operation of the shutter button 15d is detected (step S1), an evaluation value (see an AF evaluation value curve in FIG. 3) of each AF area is calculated (step S2). Next, with reference to the usage history data table 27 of FIG. 5, it is determined whether or not usage history data is stored (step S3). If the usage history data is not stored, that is, the digital camera 10 is started for the first time. When using, an AF area having the maximum gradient of the AF evaluation value curve of the evaluation value of each AF area is selected (step S6).

  On the other hand, if usage history data is stored, next, whether or not there is an AF area having the largest gradient and an AF area having the largest gradient and a gradient within a predetermined range. (Step S4), if not, the process proceeds to step S6. If present, the AF area having the maximum gradient and the gradient having the maximum gradient and a size within a predetermined range are further included. It is determined whether or not there is a difference of a predetermined value or more in the number of uses indicated by the AF area use history data (step S5). If there is no difference, the process proceeds to step S6. If there is a difference, next, the use history of the AF area having the maximum gradient and the AF area having the maximum gradient and the gradient within the predetermined range is used. The one with the larger number of uses indicated by the data is selected (step S7).

  Then, in either case of step S6 or step S7, after performing the focusing process using the selected AF area (step S8), it is determined whether or not to hold the “half-press” operation of the shutter button 15d (step S9). If it is maintained, the process returns to step S1 to re-select the AF area. If not maintained, it is determined whether or not the shutter button 15d is “fully pressed” (step S10). If it is determined that there is a “push” operation, the imaging process is executed (step S11), the usage history data of the selected AF area is updated (the number of uses is increased by +1) (step S12), and the program is terminated.

  Here, “whether there is an AF area having the largest gradient and an AF area having the largest gradient and a gradient within a predetermined range” in step S4, “the largest gradient in step S5”. Whether or not there is a difference greater than or equal to a predetermined value between the use counts indicated in the use history data of the AF area having a maximum gradient and a gradient having a magnitude within a predetermined range, and Regarding “the AF area having the largest gradient and the AF area having the largest gradient and a gradient within a predetermined range among the AF areas having the largest number of uses indicated by the use history data” in step S7, explain.

  In FIG. 3, since the AF evaluation value curve of 6E has a mountain-shaped peak with the highest gradient, the AF area corresponding to the AF evaluation value curve of 6E is “AF area having the largest gradient” in step S4. It can be said that On the other hand, the 4E AF evaluation value curve also has a mountain-shaped peak. If the height of this peak (the height from the base to the top) is within a predetermined range, it corresponds to the 4E AF evaluation value curve. It can be said that the AF area to be performed corresponds to “an AF area having a gradient having a magnitude within a predetermined range” in step S4. Therefore, in the case of FIG. 3, the determination result of step S4 is YES.

  Next, in step S5, there is a difference greater than or equal to a predetermined value in the number of uses indicated by the use history data of the AF area having the maximum gradient and the AF area having the maximum gradient and a gradient within a predetermined range. This corresponds to the “AF area having the maximum gradient”, that is, the AF evaluation value curve having the highest peak in the shape of a mountain, taking FIG. 3 as an example. The number of uses (6E → 12 times according to FIG. 5) indicated by the use history data of the AF area (6E) and “the AF area having the maximum gradient and the gradient within a predetermined range”, that is, The number of times of use (4E → 17 times according to FIG. 5) indicated by the use history data of the AF area (4E) corresponding to the AF evaluation value curve having a mountain-shaped peak within a predetermined range is compared, and the difference To determine whether or not is greater than or equal to a predetermined valueIn this case, since the difference between 12 times of 6E and 17 times of 4E is 17-12 = 5 times, if the predetermined value is 3 times for convenience, at least 12 times of 6E and 17 times of 4E Since the difference (5 times) exceeds a predetermined value (3 times), the determination result in step S5 is YES in this case.

  Next, in step S7, “the AF area having the largest gradient and the AF area having the largest gradient and a gradient within a predetermined range, which has a larger number of uses indicated by the use history data” "" Refers to the AF area 4E showing the maximum 17 times out of 17 times 4E and 12 times 6E according to the above example. That is, in this case, one AF area 4E is selected from a plurality of candidate AF areas (4E, 6E) by referring to past use history data of the AF area. Since this selected AF area (4E) is an area that is often used by a photographer, by providing such a characteristic selection characteristic, the above-described object of the present invention, that is, “multipoint” In AF, an appropriate AF area can be selected according to the photographer's intention, and thus an imaging apparatus, an imaging method, and a program capable of increasing the tendency to focus on the subject of interest can be achieved. is there.

  When the AF area 4E is selected and the focus lens is moved to a position having a peak in the corresponding AF evaluation value curve, the AF evaluation value curve corresponding to the AF area 7E is Therefore, the AF area 7E is also focused, and the final AF area selection result is as shown in FIG.

  In this case, 4E may be counted and recorded as the selected AF area in step S12, or 4E and 7E may be counted as the selected AF area.

  In the above description, the AF area is selected by comparing the use history data (the past use count of the AF area), but the present invention is not limited to this. In short, any AF area may be selected as long as it refers to a past use history.

  FIG. 8 is a diagram showing another operation flow of the shooting mode processing program including the AF area selection processing considering the use history of the AF area. In this program, first, when a “half-press” operation of the shutter button 15d is detected (step S21), an evaluation value (see an AF evaluation value curve in FIG. 3) of each AF area is calculated (step S22). Next, with reference to the usage history data table 27 of FIG. 5, it is determined whether usage history data is stored (step S23). If usage history data is stored, the calculated AF evaluation value is used. After raising the level according to the number of uses (step S24) and changing the gradient, the AF area having the maximum gradient is selected (step S25). On the other hand, if usage history data is not stored, step S24 is executed. Pass and select the AF area with the maximum gradient (step S25).

  Then, after performing the focusing process using the selected AF area (step S26), it is determined whether or not the “half-press” operation of the shutter button 15d is maintained (step S27). In order to perform selection again, the process returns to step S21, and if not maintained, the presence / absence of the “full press” operation of the shutter button 15d is determined (step S28). Is executed (step S29), the use history data of the selected AF area is updated (the number of uses is increased by +1) (step S30), and the program is terminated.

  The difference from the program of FIG. 7 is that “if usage history data is stored in the usage history data table 27, the calculated AF evaluation value is raised according to the number of uses (step S24) to change the gradient. Then, the AF area having the maximum gradient is selected (step S25).

  FIG. 9 is a conceptual diagram of raising the AF evaluation value. As shown in (a), the number of times each of 1E to 9E is used is 4, 9, 5, 3, 57, 6, 5, 5, 5 and 6. That is, it is assumed that the number of uses of the central AF area (5E) is the maximum (57 times). The AF evaluation value graph on the left side of (a) is the one before “bottom-up”, and the AF evaluation value graph on the right side is after “bottom-up”. Each of these evaluation value graphs includes four AF evaluation value curves 28a to 28d and 29a to 29d. Of these, the AF evaluation value curves 28c and 29c shown by two-dot chain lines indicate the center AF with the maximum number of uses. Corresponds to area (5E).

  When observing the AF evaluation value graph before “bottom raising”, the one-dot chain line AF evaluation value curve 28d has the maximum gradient, and the solid line AF evaluation value curve 28a has the second gradient. Therefore, if an AF area is selected based solely on the “gradient (gradient)”, in this case, the AF area corresponding to the AF evaluation value curve 28d showing the maximum change is selected.

  However, the AF area with the largest number of past uses is the center AF area (5E), and the AF evaluation value curve corresponding to this AF area (5E) is 28c. When the AF area is selected based only on the “gradient magnitude”, it cannot be denied that the AF area may be selected against the photographer's intention.

  On the other hand, in the AF evaluation value graph after “lifting up”, the AF evaluation value curve 29c is “bottomed up” and the gradient changes according to the past number of times of use. Therefore, the gradient of the AF evaluation value curve 29c is changed. Is apparently the maximum, and the AF area can be selected according to the photographer's intention. Incidentally, “raising the bottom” is a term for convenience that means increasing the gradient (slope) of the AF evaluation value curve. Such raising can be performed by, for example, a method of multiplying a value (typically, a differential value) representing a change in the AF evaluation value curve by a predetermined coefficient, but the present invention is not limited to this. Any method can be used as long as the method is obtained.

  As described above, according to the embodiment using the operation program of FIG. 7 (hereinafter referred to as the first embodiment), the gradient (slope) of the AF evaluation value is the highest in the digital camera equipped with the contrast multi-AF. When there is another area with a large area and the largest gradient and a gradient within a predetermined threshold, the AF is focused according to the number of times the AF area corresponding to the plurality of curves is used. Since the area is selected, it is possible to provide an imaging apparatus, an imaging method, and a program that can easily focus on the AF area intended by the photographer.

  If the number of times of use is very small (4E is 33 times, 6E is 32 times, etc.), the area where the change amount of the AF evaluation value is the highest is given priority without considering the number of times. Further, the number of times of use may be considered only when the difference in the number of times of use is greater than or equal to a predetermined range (for example, when there is a difference of 5 times or more).

  Further, according to the embodiment using the operation program of FIG. 8 (hereinafter referred to as the second embodiment), the gradient of the corresponding AF evaluation value is raised according to the number of times of use of the AF area (the gradient gradient is sharpened). As a result of raising the bottom, the area having the largest gradient is selected (that is, the slope of the corresponding curve is raised according to the number of times the AF area is used), so that an extremely specific AF area is selected. Even if there is a large number of images biased to (for example, 5E), the AF area (5E) can be selected because the 5E pseudo curve with a small gradient is raised so as to have a large gradient. As a result, it is possible to provide an imaging apparatus, an imaging method, and a program that can easily focus on the AF area intended by the photographer.

  In addition, raising the bottom may be performed according to the number of times of use, or a rank may be given according to the number of times of use, and this rank may be performed. A combination with the first embodiment is also possible.

  In the above description, the pseudo curve of the AF evaluation value is obtained and the AF area is selected from the magnitude of the gradient. However, the magnitude of the difference between the maximum value and the minimum value of the AF evaluation value is not the gradient. Alternatively, the AF area may be selected based on the maximum AF evaluation value.

  In the first embodiment, the AF area is selected according to the number of times of use. However, the number of times of use may be used after the number of times of use for a predetermined number of times is recorded.

  In the first embodiment, when the difference in the number of times of use is less than a predetermined value, the number of times of use is not used and the AF area having the maximum AF evaluation value gradient is selected. This difference may not be used.

  In the second embodiment, the gradient of the AF evaluation value is raised (increase the gradient) according to the number of times of use. However, the gradient of the AF evaluation value in the AF area where the number of times of use is less than the predetermined number of times is reduced. It may be lowered (decrease the inclination).

  Further, in the second embodiment, for raising the bottom, an amount corresponding to the number of times of use may be raised, or an amount corresponding to the rank of the number of times of use may be raised.

  In the first and second embodiments, the photographing process is performed in response to the “full press” operation of the shutter button 15d. However, the “half press” operation of the shutter button 15d is maintained after the focusing process. In this case, the photographing process may be performed. Alternatively, the photographing process may be performed immediately after the focusing process is completed.

  Further, the timing for counting the AF area selected at the time of focusing (update of usage history data) may be any time during shooting instruction, during shooting processing, or when saving a shot image.

  Further, the count result is stored in the use history data table 27. However, the present invention is not limited to this, and for example, the count result may be recorded as shooting information in a captured image. In addition, the number of times may be taken into account from the AF area selected when the image stored in the memory mounted on the imaging apparatus is captured.

  Further, the two embodiments (the first embodiment and the second embodiment) may be combined. That is, the gradient of the corresponding AF evaluation value is raised according to the number of times of use of the AF area, and as a result of raising the bottom, there are other areas having the gradient of the area where the gradient of the AF evaluation value is the largest and the gradient within a predetermined threshold. When the AF area exists, the AF area to be focused may be selected according to the number of times the AF area corresponding to the plurality of curves is used.

  Further, in each of the above-described embodiments, no particular mention has been made of how to hold the digital camera 10 in the vertical and horizontal directions (that is, vertical shooting set in the vertical direction and horizontal shooting set in the horizontal direction). When leaving it as a history, it may be left separately for each way. That is, the usage history data table 27 of FIG. 5 may be modified as follows.

  FIG. 10 is a diagram showing a modification of the usage history data table 27. In this figure, the usage history data table 27 is the same as the usage history data table 27 shown in FIG. 5 in that it has an AF area number field 27a and a history data field 27b. The difference is that the subfields 27c and 27d are divided into two for vertical shooting and horizontal shooting. The vertical shooting subfield 27c stores the number of AF area selections when the digital camera 10 is shot in the vertical direction. The horizontal shooting subfield 27d holds the digital camera 10 in the horizontal direction. The number of times the AF area is selected is stored. The holding method can be distinguished by, for example, providing an appropriate sensor (such as a gravity sensor) inside the digital camera 10.

  In this way, it is possible to record the number of times of focusing separately according to the position of the digital camera 10 (vertical orientation, landscape orientation), and AF control is performed so that focusing is performed in consideration of the orientation of the digital camera 10. Therefore, it is possible to select an appropriate AF area corresponding to an actual photographing tendency.

It is a conceptual block diagram of a digital camera. It is a conceptual functional block diagram of AF control in this embodiment. It is a conceptual diagram of contrast AF. It is a figure which shows AF area selection. It is a conceptual diagram of the use history data table of AF area. It is the figure which applied the history data stored in the use history data table 27 to each AF area. FIG. 10 is a diagram (first embodiment) illustrating an operation flow of a shooting mode processing program including an AF area selection process considering an AF area use history. FIG. 12 is a diagram (second embodiment) illustrating another operation flow of a shooting mode processing program including an AF area selection process in consideration of an AF area use history. It is a conceptual diagram of raising the AF evaluation value. It is a figure which shows the modification of the usage log data table. It is a figure which shows AF area of multipoint AF. It is an operation | movement conceptual diagram of multipoint AF.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Digital camera 11a AF mechanism 14 Focus drive part 24 Contrast AF control part 27 Usage history data table

Claims (11)

For each of a plurality of AF areas set within the shooting angle of view, storage means for storing data representing the number of times used for focusing processing as a history,
A selection unit that selects an AF area that has been used many times as an AF area to be focused based on a history stored in the storage unit during the focusing process;
An imaging apparatus comprising: An acquisition means for acquiring an AF evaluation value curve for each of the plurality of AF areas during the focusing process;
About the gradient of each AF evaluation value curve acquired by the acquisition means, the AF area having the maximum size within the shooting field angle, and the AF area having a size within a predetermined threshold from the maximum size First determination means for determining whether or not exists,
Further comprising
The selecting means selects an AF area to be focused from the existing AF areas according to the history stored in the storage means when it is determined by the first determination means. The imaging apparatus according to claim 1, wherein the imaging apparatus is characterized.   3. The selection unit, when it is determined by the first determination unit that the AF area is used more frequently in the history stored in the storage unit, is selected. The imaging device described in 1. When it is determined by the first determination means that the AF area having the maximum size is used for the focusing process and the AF area having a size within a predetermined threshold from the maximum size. A second determination unit for determining whether or not a difference from the number of times used for the focusing process is a predetermined value or more;
The imaging apparatus according to claim 2, wherein the selection unit selects an AF area that is used more frequently when the second determination unit determines that there is a predetermined number or more. Change means for changing the magnitude of the gradient of each AF evaluation value curve acquired by the acquisition means based on the history stored in the storage means;
Further comprising
The imaging apparatus according to claim 2, wherein the selection unit selects an AF area based on the magnitude of the gradient changed by the changing unit.   The imaging apparatus according to claim 2, wherein the AF evaluation value is a change amount of contrast. Imaging means for imaging in the AF area selected by the selection means;
A storage control means for controlling the storage means to increase the number of times of use corresponding to the selected AF area when imaged by the imaging means;
The imaging apparatus according to claim 1, further comprising: A third determination unit that determines the vertical and horizontal directions of the imaging apparatus during the focusing process;
The imaging apparatus according to claim 7, wherein the storage control unit controls to increase the number of times of use according to the vertical and horizontal directions determined by the third determination unit. A shooting mode setting means for selectively setting a plurality of shooting modes with different shooting conditions;
The imaging apparatus according to claim 7, wherein the storage control unit performs control so as to increase the number of times used for each photographing mode. A detection step of detecting an instruction for focusing processing;
When a focus processing instruction is detected in this detection step, a focus step for performing the focus processing with reference to data representing the number of times used for the focus processing for each of a plurality of AF areas stored in advance in the memory. When,
A determination step for determining whether or not the photographing process is performed in a state where the focusing process is performed in the focusing step;
A storage control step and means for controlling the memory so as to increase the number of times of use corresponding to the AF area when it is determined that the photographing process is performed in this determination step;
An imaging method comprising: A computer included in the imaging apparatus;
Detecting means for detecting an instruction for focusing processing;
When detecting the focus processing instruction by the detection means, the focus means for performing the focus processing with reference to data representing the number of times used for the focus processing for each of the plurality of AF areas stored in the memory in advance,
Determining means for determining whether or not the photographing process is performed in a state where the focusing process is performed by the focusing means;
A program which functions as a storage control means for controlling the memory so as to increase the number of times of use corresponding to this AF area when it is determined that the photographing process is performed by the determination means.

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