JP5304756B2 - Camera, camera control program, and camera control method - Google Patents

Description

  The present invention relates to a camera, a camera control program, and a camera control method having a multi-AF (Auto Focus) function for performing auto focus adjustment by detecting focus in a plurality of focus detection areas.

  Conventionally, a camera having a multi-AF function capable of changing a focus detection area has been proposed. This camera first performs focus detection (multi-AF) for all of a plurality of focus detection areas to acquire focus detection information for each focus detection area. Next, one of the focus detection areas is determined based on the focus detection information for the plurality of focus detection areas, and the focus lens is driven and focused based on the focus detection information corresponding to the determined detection area. Further, when the determined focus detection area does not match the subject intended by the photographer, the focus detection area is changed according to a predetermined operation by the photographer. Based on the focus detection information corresponding to the changed detection area, the focus lens can be driven and focused to focus on the subject intended by the photographer (for example, a patent) Reference 1 and Patent Reference 2).

Japanese Patent Laid-Open No. 7-168083 JP 2004-53636 A

  However, in such a conventional camera, multi-AF is performed to acquire focus detection information for each focus detection area, and the focus detection area determined based on the focus detection information for the plurality of focus detection areas is the intended subject. The photographer determines whether or not they match, and if they do not match, the focus detection area is changed by performing a predetermined operation, and has already been acquired by the multi-AF corresponding to the changed predetermined detection area. AF is performed based on the focus detection information. Therefore, from the time when focus detection is performed and focus detection information is acquired for each focus detection area until AF is performed based on the focus detection information corresponding to the changed predetermined detection area, it is caused by the judgment and operation of the photographer. A considerable time lag occurs inevitably.

  On the other hand, the subject intended by the photographer is not always static and may be dynamic. Therefore, when the intended subject is dynamic, if there is a change in the front-rear direction, the intended subject will be focused even if the focus detection area is changed and AF is performed based on the corresponding focus detection information. Will not be possible.

  The present invention has been made in view of the conventional problems, and a camera, a camera control program, and a camera control method capable of automatically adjusting a focus on an intended subject even when the subject has changed. Is intended to provide.

In order to solve the above-described problem, the camera according to the first aspect of the present invention includes a multifocal detection unit that detects a focal point of an optical system for a plurality of focus detection areas and acquires focus information, and the multifocal detection unit. Selection means for selecting any of the plurality of focus detection areas based on the acquired plurality of focus information, reoperation control means for re-operating the selection means in response to a predetermined operation, and multi-focus detection means There the object image at the time of detection of the focus for a plurality of focus detection areas, and a comparing means for the re-operation control means for comparing the object image at the time of re-operating the selecting means, the re-operation control means When the two subject images have changed by a predetermined threshold or more based on the comparison result of the comparison means, a plurality of focus detection areas including a focus detection area already selected by the selection means. The selection means selects one of the plurality of focus detection areas without changing the selection criterion of the focus detection area by the selection means, and the comparison means Based on the comparison result, when the two subject images have not changed more than a predetermined threshold, the selection unit selects the other focus detection area except the focus detection area already selected by the selection unit, or the selection The selection means selects one of the plurality of focus detection areas after changing the selection criterion of the focus detection area by the means.

  Therefore, when the subject image when the multi-focus detection unit detects the focus for a plurality of focus detection areas and the subject image when the re-operation control unit re-activates the selection unit are changed by a predetermined threshold value or more. The selection means allows the selection means to select one of a plurality of focus detection areas including the focus detection area already selected by the selection means, or a plurality of focus detections without changing the focus detection area selection criteria by the selection means. Let the selection means select one of the areas. Therefore, when there is a change greater than the predetermined threshold, that is, when there is a change greater than the predetermined value in the subject, the same focus detection area may be selected again. As a result, even when the main subject to be photographed has changed, it is possible to perform photographing while matching the main subject with the focus detection area.

  When the subject image when the multi-focus detection unit detects the focus for a plurality of focus detection areas and the subject image when the re-operation control unit re-activates the selection unit do not change more than a predetermined threshold. The selection means selects other focus detection areas other than the focus detection area already selected by the selection means, or changes the focus detection area selection criteria by the selection means and selects any of the plurality of focus detection areas. Is selected by the selection means. Therefore, the probability that the newly selected focus detection area matches the main subject to be photographed that exists in a focus detection area different from the previously selected focus detection area increases, and the focus detection area matches the main subject. This makes it easy to shoot.

According to a second aspect of the present invention, there is provided a camera control program comprising: a multi-focal point detection means for detecting a focal point of an optical system for a plurality of focal point detection areas and acquiring focal point information; Selection means for selecting any of the plurality of focus detection areas based on a plurality of focus information acquired by the focus detection means, a re-operation control means for re-activating the selection means in response to a predetermined operation, and The multi-focal point detection unit functions as a comparison unit that compares the subject image when the focus is detected for a plurality of focus detection areas and the subject image when the re-operation control unit re-activates the selection unit. The motion control means, when the two subject images have changed more than a predetermined threshold based on the comparison result of the comparison means, the focus already selected by the selection means. The selection unit causes the selection unit to select any one of a plurality of focus detection areas including a detection area, or the selection unit selects any one of the plurality of focus detection areas without changing a selection criterion for the focus detection area by the selection unit. And when the two subject images have not changed more than a predetermined threshold based on the comparison result of the comparison means, the selection means selects a focus detection area other than the focus detection area already selected by the selection means. Or selecting one of the plurality of focus detection areas after changing the selection criteria of the focus detection area by the selection means. Therefore, when the computer executes processing according to this program, the same effects as those of the first aspect of the invention can be obtained.

In the camera control method according to the third aspect of the invention, the multifocal detection step of detecting the focal point of the optical system and acquiring the focal point information for a plurality of focus detection areas, and the multifocal detection step. A selection step for selecting one of the plurality of focus detection areas based on a plurality of focus information, a re-operation control step for re-operating the selection step in response to a predetermined operation, and a plurality of detection steps in the multi-focus detection step. A comparison step of comparing a subject image when a focus is detected with respect to the focus detection area and a subject image when the selection step is re-activated in the re-operation control step, and the re-operation control step includes Based on the comparison result of the comparison process, when both the subject images have changed by a predetermined threshold value or more, a plurality of focus detection areas including the focus detection area already selected by the selection process are selected. The selection step selects one of the plurality of focus detection areas without changing the focus detection area selection criteria in the selection step, and the comparison result of the comparison step If the two subject images have not changed by a predetermined threshold value or more, the focus detection area other than the focus detection area already selected by the selection step is selected by the selection step, or by the selection step. After changing the selection criteria of the focus detection area, any of the plurality of focus detection areas is selected in the selection step. Therefore, by performing the processing according to the described steps, the same effects as those of the first aspect of the invention can be achieved.

As described above, according to the inventions according to claims 1, 2 and 3 , the subject image when the multi-focus detection means (or the multi-focus detection step) detects the focus for a plurality of focus detection areas, and the re-operation control means. If the subject image when the selection means (or the selection process) re-activates (or the re-operation control step) changes more than a predetermined threshold value, the focus detection area already selected by the selection means is selected. Either one of the plurality of focus detection areas is selected by the selection unit, or one of the plurality of focus detection areas is selected by the selection unit without changing the selection criterion of the focus detection area by the selection unit. Therefore, when there is a change greater than or equal to the predetermined threshold, that is, when there is a change greater than or equal to the predetermined value, the same focus detection area can be selected again. As a result, even when the main subject to be photographed has changed, it is possible to perform photographing while matching the main subject with the focus detection area.

  When the subject image when the multi-focus detection unit detects the focus for a plurality of focus detection areas and the subject image when the re-operation control unit re-activates the selection unit do not change more than a predetermined threshold. The selection means selects other focus detection areas other than the focus detection area already selected by the selection means, or changes the focus detection area selection criteria by the selection means and selects any of the plurality of focus detection areas. Is selected by the selection means. Accordingly, it is possible to increase the probability that the newly selected focus detection area matches the main subject to be photographed that exists in a focus detection area different from the previously selected focus detection area, and focus detection is performed on the main subject. It is possible to facilitate shooting by matching the areas.

It is a block diagram which shows the electric constitution of the digital camera which concerns on one embodiment of this invention. (A) is a diagram showing focus frames [1] to [5], (B) is a diagram showing a display example of a liquid crystal monitor, and (C) is an example of an AF evaluation value for each of the focus frames [1] to [5]. FIG. It is a flowchart which shows the process sequence of the 1st Embodiment of this invention. It is a flowchart which shows the process sequence of the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence in the modification of the 2nd Embodiment of this invention. It is a flowchart which shows the process sequence of the 3rd Embodiment of this invention.

  (First embodiment)

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a circuit configuration of a digital camera 10 to which an embodiment of the present invention is applied. This digital camera 10 has general functions such as AE and AWB as well as a multi-AF function described later. It is what you have. That is, the lens block 11 includes an optical system such as a zoom lens and a focus lens, and a drive mechanism for driving the optical system. The optical system is optically driven by a motor 12 provided in the drive mechanism. Driven in the axial direction. In the present embodiment, the AF detects the AF evaluation value (contrast value) of the image captured at each position while moving the focus lens in the optical axis direction, and focuses the peak position of the AF evaluation value. This is a contrast detection method for position.

  A motor driver 16 is connected to a CPU 13 that controls the entire digital camera 10 via a bus 14 and a timing generator (TG) 15. The motor driver 16 is connected to a timing generator 15 according to a command from the CPU 13. The motor 12 is driven based on the generated timing signal. The strobe 17 is also driven by a timing signal generated by the timing generator 15.

  The digital camera 10 has a CCD 18 as an image sensor. The CCD 18 is disposed on the optical axis of the lens block 11, and the subject is imaged on the light receiving surface of the CCD 18 by the lens block 11. The CCD 18 is driven by a vertical and horizontal driver 19 based on a timing signal generated by the timing generator 15 in accordance with a command from the CPU 13, and outputs an analog imaging signal corresponding to the optical image of the subject to the unit circuit 20. The unit circuit 20 includes a CDS circuit that removes noise included in the output signal of the CCD 18 by correlated double sampling, an A / D converter that converts an imaging signal from which noise has been removed into a digital signal, and the like. The converted imaging signal is output to the image processing unit 21.

  The image processing unit 21 performs processing such as pedestal clamping on the input image pickup signal, converts it into a luminance (Y) signal and a color difference (UV) signal, and performs image processing such as auto white balance, contour enhancement, and pixel interpolation. Perform digital signal processing to improve quality. The YUV data converted by the image processing unit 21 is sequentially stored in the SDRAM 22 and, in the REC through mode, is converted into a video signal every time one frame of data (image data) is accumulated, and the backlight (BL) The image is sent to a liquid crystal monitor (LCD) 23 having 24 and displayed on the screen as a through image.

  In the still image shooting mode, with the shutter key operation as a trigger, the CPU 13 starts from the through image shooting mode (REC through mode) to the CCD 18, the vertical and horizontal drivers 19, the unit circuit 20, and the image processing unit 21. The switching to the still image shooting mode is instructed, and the image data obtained by the shooting process in the still image shooting mode and temporarily stored in the SDRAM 22 is compressed by the CPU 13 and finally as a still image file of a predetermined format. Recorded in the external memory 25. In the movie recording mode, a plurality of image data sequentially stored in the SDRAM 22 is sequentially compressed by the CPU 13 between the first shutter key operation and the second shutter key operation, and recorded in the external memory 25 as a moving image file. Is done. The still image file and the moving image file recorded in the external memory 25 are read out and expanded by the CPU 13 in accordance with the user's selection operation in the PLAY mode, and expanded on the SDRAM 22 as YUV data, and then displayed on the liquid crystal monitor 23. Is done.

  In the flash memory 26, various programs for causing the CPU 13 to control the respective units, for example, a program for controlling AE, AF, and AWB, a program for data communication, and further, the CPU 13 controls the selecting means and the optical system of the present invention. Various programs such as programs for functioning as means, photographing instruction detection means, reoperation control means, and the like are stored.

  In addition, the digital camera 10 includes a key input unit 27 including a plurality of operation keys and switches such as a power switch, a mode selection key, a shutter key, a zoom key, and a focus frame selection key for manually selecting a focus frame, which will be described later. A rechargeable battery 28 such as a battery, a power supply control circuit 29 for supplying power of the battery 28 to each unit, and a microcomputer 30 for controlling them are provided. The microcomputer 30 constantly scans the key input unit 27 for operation of the operation key, and when a user operates any operation key, sends an operation signal corresponding to the operation content to the CPU 13. . The shutter key has a so-called half shutter function that can be half-pressed and fully pressed.

  The digital camera 10 has a recording function for recording ambient sounds in the movie recording mode. The CPU 13 has a speaker (SP) 33 and a microphone via an audio chip 32 having an audio processing circuit. (MIC) 34 is connected. In the movie recording mode, the audio chip 32 processes the audio waveform input from the microphone 34 and inputs the audio waveform data to the CPU 13. Then, the CPU 13 compresses the audio waveform data input from the audio chip 32 between the first and second shutter key operations in the movie recording mode, and the moving image with sound including the compressed ambient sound data and the compressed moving image data. A file is generated and recorded in the external memory 25. The moving image file with sound recorded in the external memory 25 is reproduced by the speaker 33 after the surrounding sound data is converted into a sound waveform by the sound chip 32 when the moving image data is reproduced in the PLAY mode.

  As shown in FIG. 2A, the digital camera 10 having the above configuration forms a focus frame [1] to [1] in the subject image that is imaged on the light receiving surface of the CCD 18 by the lens block 11 and displayed on the liquid crystal monitor 23. 5] is performed. Therefore, when the still image shooting mode is set and the multi AF mode is set with the power on, the focus frame [1] to [5] shown in FIG. It is displayed in a predetermined normal color (for example, green).

  In this state, the CPU 13 executes processing as shown in the flowchart of FIG. 3 based on the program stored in the flash memory 26. In the shooting standby state in which the through image shooting mode is set, first, a through image display process is started (step S101), and a through image is displayed on the liquid crystal monitor 23. Next, it is determined whether or not the shutter key is half-pressed (step S102), and the process waits until the shutter key is half-pressed. If the shutter key is half-pressed, it is determined whether it is within 2 seconds from the previous release of the shutter key (step S103). If it is not within 2 seconds, the process proceeds to step S105 without executing the process of step S104, and the multi-AF process is executed.

  That is, the AF evaluation value (contrast value) of the image is detected for each of the focus frames [1] to [5] with the focus lens positioned at the near end (shortest shooting distance). Subsequently, the focus lens is moved one step toward the far end (∞) side, and the AF evaluation value (contrast value) of the image is similarly detected for each of the focus frames [1] to [5]. The above processing is performed from the near end to the far end of the focus lens, and in this embodiment, at each movement position from step 1 to step 6 of the focus lens. Then, the evaluation values of steps 1 to 6 of the focus frames [1] to [5] are stored in the SDRAM 22. Therefore, for example, if a subject as shown in FIG. 2B is imaged and displayed on the liquid crystal monitor 23, the SDRAM 22 has focus frames [1] to [5] as shown in FIG. Each evaluation value is stored in relation to the focus lens moving step.

  Next, focus frame selection display / AF processing is executed (step S106). That is, one of the focus frames [1] to [5], for example, the focus frame with the shortest distance to the subject, that is, the focus frame with the closest AF evaluation value peak value is selected, and the selected focus frame. Is changed to a color different from the normal color (green). Further, the focus lens is driven to the lens position where the peak value is detected in the selected focus frame so that the image in the selected focus frame is in focus. Therefore, in the example shown in FIG. 2, the focus frame [4] having a peak near Step 1 of the lens is selected and changed to a different color so that the image in the focus frame [4] is focused. In addition, the focus lens is driven.

  Subsequently, by repeating the loop of steps S107 and S108, it is determined whether or not the shutter key is fully pressed (step S107) or whether or not the half-press operation of the shutter key is released (step S108). At this time, the photographer confirms the relationship between the focus frame whose display color has changed and the subject on the liquid crystal monitor 23, and if the focus position is the focus frame, that is, “flower” shown in FIG. If you have taken a picture in focus, press the shutter key fully. As a result, the determination in step S107 becomes YES, and the process proceeds from step S107 to step S109 to shift to the capture process. That is, as described above, the CPU 13 switches from the through image shooting mode to the still image shooting mode for the CCD 18, the vertical and horizontal drivers 19, the unit circuit 20, and the image processing unit 21 with the full press of the shutter key as a trigger. The image data obtained by the photographing process in the still image photographing mode and temporarily stored in the SDRAM 22 is compressed and finally recorded in the external memory 25 as a still image file of a predetermined format.

  However, if the focus position intended by the photographer is a subject within another focus frame (for example, “person” instead of “flower”), release the shutter key halfway once. Press the shutter key halfway again within 2 seconds. Then, after the determination in step S108 is YES and the process returns to step S102, both the determination in step S102 and the determination in step S103 are YES, and the process proceeds from step S103 to step S104.

  Then, the selected focus frame up to the previous time, that is, the focus frame selected in step S106 until the previous time is deleted and deleted from the liquid crystal monitor 23 (step S104). Further, the multi-AF is performed on the remaining focus frame excluding the deleted focus frame (step S105). Therefore, after the multi AF is executed in the previous step S105 and before the multi AF is executed again in this step S104, even if the subject has a change in the front-rear direction, the change is caused by executing the multi AF again. It is possible to shoot an image focused on the (existing) focus frame with respect to the subject where there was.

  In step S106, one of the remaining focus frames [1] to [5], the focus frame having the shortest distance to the subject is selected, and the selected focus frame is defined as the normal color (green). The color is changed to a different color, and the same processing as described above is executed.

  In this embodiment, if the shutter key is half-pressed within 2 seconds from the release of the previous half-press operation of the shutter key, the determination in step S103 is YES and the process in step S104 is executed. Therefore, there are cases where all the focus frames are deleted. Therefore, in this case, multi-AF is again performed for all the focus frames in step S105, and all the focus frames [1] to [5] are also displayed on the liquid crystal monitor 23.

  In this embodiment, the selected focus frame up to the previous time is deleted in step S104, but multi-AF is performed in step S105 for all the focus frames [1] to [5] without deleting them. In step S106, the focus frame is selected based on a different standard from the previous time. For example, the focus frame corresponding to the object at the shortest distance is selected for the first time, and the focus frame corresponding to the object at long distance is selected for the second time and thereafter. You may make it do.

  In this embodiment, when the shutter key is pressed halfway again within 2 seconds from the release of the shutter key halfway, the selection focus frame up to the previous time is deleted and multi-AF is performed again. In response to a predetermined key operation, the previously selected focus frame may be deleted and multi-AF may be performed again. In addition, AF may be performed by reselecting the focus frame based on the information by the multi AF performed in advance similarly to the above-described prior art without performing the multi AF (step S105) again.

  (Second Embodiment)

  4 and 5 are flowcharts showing a processing procedure in the second embodiment of the present invention. In this embodiment, the number of times the focus frame used for photographing is stored in the flash memory 26, and the focus frame is automatically selected based on the number of times used. That is, when the focus frame manual selection mode is previously set in the key input unit 27, the processing shown in the flowchart shown in FIG. 4 is executed. First, a through image display process is started (step S201), and a through image is displayed on the liquid crystal monitor 23. Next, all the focus frames [1] to [5] are displayed on the liquid crystal monitor 23 on which the through image is displayed (step S202). Then, it is determined whether or not any focus frame has been selected by the operation of the key input unit 27 (step S203), and waits until it is selected. If any one of the focus frames is selected, the non-selected focus frame that has not been selected is deleted from the liquid crystal monitor 23, and only the selected focus frame remains (step S204).

  Next, it is determined whether or not the shutter key is half-pressed (step S205), and the process waits until the shutter key is half-pressed. If the shutter key is half-pressed, contrast AF processing is executed, and the focus lens is driven so that the displayed image within the focus frame is in focus (step S206). Subsequently, by repeating the loop of steps S207 and S208, it is determined whether or not the shutter key is fully pressed (step S207) or whether or not the half-press operation of the shutter key is released (step S208). At this time, the photographer confirms the relationship between the focus frame that is displayed only on the liquid crystal monitor 23 and the subject, and if the focus position is within this focus frame, fully presses the shutter key. As a result, the determination in step S207 is YES, and the count value of the focus frame selected when the shutter key is fully pressed is incremented in the flash memory 26 (step S209). Thereafter, the process proceeds to the capture process (step S210).

  If the focus position intended by the photographer is a subject in another focus frame, the shutter key half-press operation is once released. Then, the determination in step S208 is YES, and the process returns to step S202.

  On the other hand, when the multi-AF mode is previously set in the key input unit 27, the processing shown in the flowchart shown in FIG. 5 is executed. That is, through image display processing is started (step S301), and a through image is displayed on the liquid crystal monitor 23. Next, it is determined whether or not the shutter key is half-pressed (step S302), and the process waits until the shutter key is half-pressed. If the shutter key is half-pressed, it is determined whether it is within 2 seconds from the release of the previous half-press operation of the shutter key (step S303). If it is not within 2 seconds, it is determined whether there is a focus frame that exceeds a predetermined number of selections based on the number of times of use of the focus frames [1] to [5] stored in the flash memory 26. (Step S304), if not, the process proceeds to Step S308 described later.

  If there is a focus frame exceeding the predetermined number of times of use, the focus frame having the largest number of selections is selected and displayed on the liquid crystal monitor 23 (step S305). Then, the focus lens is driven so that the image within the displayed focus frame is in focus (step S306). Subsequently, the loop of steps S310 and S311 is repeated to determine whether or not the shutter key is fully pressed (step S310) or whether or not the half-press operation of the shutter key is released (step S311). At this time, the photographer confirms the relationship between the focus frame displayed on the liquid crystal monitor 23 and the subject. If the focus position is within this focus frame, the photographer fully presses the shutter key. As a result, the determination in step S310 becomes YES, and the process proceeds from step S310 to step S312. In the flash memory 26, the count value of the focus frame selected when the shutter key is fully pressed is counted up (step S312). ). Thereafter, the process proceeds to the capture process (step S313).

  However, when the focus position intended by the photographer is the subject in another focus frame, the half-press operation of the shutter key is once released, and the shutter key is pressed halfway again within 2 seconds. Then, after the determination in step S311 is YES and the process returns to step S302, both the determination in step S302 and the determination in step S303 are YES, and the process proceeds from step S303 to step S307.

  Then, the selected focus frame up to the previous time, that is, the focus frame selected in step S305 or step S309 described later is deleted, and the remaining focus frames excluding the deleted focus frame are displayed on the liquid crystal monitor 23 (step S307). ). Further, the multi-AF is performed on the remaining focus frames excluding the deleted focus frame (step S308). In step S309, one of the remaining focus frames [1] to [5], the focus frame having the shortest distance to the subject is selected, and the selected focus frame is defined as the normal color (green). The focus lens is driven to the lens position where the peak value is detected in the selected focus frame so that the image in the selected focus frame is in focus, and the same processing as described above is executed. .

  In the present embodiment, the flash memory 26 counts and stores the automatically selected focus frame use count and the manually selected focus frame use count without identifying them. Both may be counted separately and stored, and the focus frame may be automatically selected based on one of the count values. Also, only the number of times of use of the focus frame automatically selected by the multi-AF is stored, and the focus frame is automatically selected based on this, or only the number of times of use of the manually selected focus frame is stored. Based on this, the focus frame may be automatically selected.

  Further, in this embodiment, after determining whether or not there is a focus frame exceeding the predetermined number in step S304, the focus frame having the largest number of selections is selected, but without making the above determination. The focus frame with the largest number of selections may be selected. In this embodiment, as described above, it is determined whether or not there is a focus frame exceeding a predetermined number of times, that is, the absolute value of the number of selections is determined. You may make it judge using relative values, such as whether the difference with the focus frame with many selections is more than predetermined.

  In the present embodiment, as in the above-described embodiment, in step S309, one of the remaining focus frames [1] to [5], which is the shortest distance to the subject, is selected. However, a focus frame having a large number of selections may be sequentially selected.

  Also in this embodiment, when the shutter key is pressed halfway again within 2 seconds after the shutter key is half pressed, the selection focus frame up to the previous time is deleted and multi AF is performed again. Alternatively, in response to a predetermined key operation, the previously selected focus frame may be deleted and multi-AF may be performed again. Alternatively, AF may be performed by reselecting a focus frame based on information obtained by using multi AF performed in advance in the same manner as the above-described conventional technique without performing multi AF (step S308) again.

  In the present embodiment, the case where the number of times of selection is stored as the selection history of the focus detection area has been shown. However, the present invention is not limited to this, for example, the focus detection area selected together with the selection date and time is stored, The selection history and its criteria may be of any configuration, such as selecting a focus detection area based on the recent selection frequency.

  (Modification of the second embodiment)

  FIG. 6 is a flowchart showing a processing procedure in a modification of the second embodiment of the present invention. In this flowchart, steps S401 to S404 and S406 to S414 other than step S405 are the same as steps S301 to S313 in the flowchart shown in FIG. Then, in the only different step S405, the focus frame with the least number of uses is deleted based on the number of times of use of the focus frames [1] to [5] stored in the flash memory 26, and the deleted focus frame is removed. The remaining focus frame is displayed on the liquid crystal monitor 23. Therefore, according to this modification, when there is a focus frame whose number of use exceeds the predetermined number (step S404; YES), the multi-AF described above is excluded in step S409 except for the focus frame with the least number of use. Will be executed. However, if there is no focus frame in which the number of times of use exceeds the predetermined number (step S405; NO), the focus frame having the least number of times of use is not excluded, and the remaining focus frame is described above. Multi AF is executed.

  In this modification, the focus frame with the smallest number of uses is deleted, but the focus frames with the least number of uses may be deleted.

  Also in this embodiment, when the shutter key is pressed halfway again within 2 seconds after the shutter key is half pressed, the selection focus frame up to the previous time is deleted and multi AF is performed again. Alternatively, in response to a predetermined key operation, the previously selected focus frame may be deleted and multi-AF may be performed again. Alternatively, AF may be performed by reselecting a focus frame based on information obtained by using multi AF performed in advance in the same manner as the above-described conventional technique without performing multi AF (step S308) again.

  (Third embodiment)

  FIG. 7 is a flowchart showing a processing procedure in the third embodiment of the present invention. In this embodiment, the subject image when the multi-AF is performed and the subsequent subject image are compared, and if both change more than the threshold value, the multi-AF is performed again at that time. is there. In the shooting standby state in which the through image shooting mode is set, first, a through image display process is started (step S501), and a through image is displayed on the liquid crystal monitor 23. Next, it is determined whether or not the shutter key is half-pressed (step S502), and the process waits until the shutter key is half-pressed. If the shutter key is half-pressed, it is determined whether or not it is within 2 seconds from the release of the previous half-press operation of the shutter key (step S503). If it is not within 2 seconds, the process proceeds to step S506 without performing the processes of steps S504 to S507, and all the focus frames are displayed on the liquid crystal monitor 23. Then, multi-AF processing is executed corresponding to the focus frame displayed on the liquid crystal monitor 23. At this time, the subject image when the multi-AF is performed is stored in the SDRAM 22 (step S509).

  Next, the above-described focus frame selection display / AF processing is executed (step S510), and then the loop of steps S511 and S512 is repeated to determine whether or not the shutter key is fully pressed (step S511), or the shutter key. It is determined whether or not the half-press operation has been released (step S512). At this time, the photographer confirms the relationship between the focus frame whose display color has changed and the subject on the liquid crystal monitor 23, and if the focus position is the focus frame, the photographer fully presses the shutter key. As a result, the determination in step S511 becomes YES, and the process proceeds from step S511 to step S513 to shift to the capture process. However, when the focus position intended by the photographer is the subject in another focus frame, the half-press operation of the shutter key is once released, and the shutter key is pressed halfway again within 2 seconds. Then, the determination in step S512 is YES, and after returning to step S502, both the determination in step S502 and the determination in step S503 are YES, and the process proceeds from step S503 to step S504.

  Then, the subject image stored in the SDRAM 22 in S509 is compared with the subject image captured at the present time (halfway when the shutter key is pressed) from the CCD 18 (step S504), and whether there is a difference greater than a predetermined threshold. It is determined whether or not (step S505). If there is no difference greater than the threshold value and the current subject does not change by more than the threshold value relative to the subject image during the multi-AF, the selected focus frame up to the previous time, that is, the focus frame selected in step S510 until the previous time is selected. Delete and erase from the liquid crystal monitor 23 (step S507).

  However, if a change equal to or greater than the threshold value occurs in the subject, the process proceeds from step S505 to step S506, and all the focus frames are displayed on the liquid crystal monitor 23. Therefore, even if the processing in step S507 has already been performed and the previous focus frame has been deleted, this deletion is canceled and all the focus frames are displayed on the liquid crystal monitor 23. Accordingly, in this case, in step S508, multi-AF is performed corresponding to all the focus frames, and the processing after step S509 described above is executed. Therefore, when a change in the left / right / up / down direction occurs in the subject, the focus is detected again for each focus frame with respect to the changed subject by changing to the multi-AF process using all the focus frames. It will be.

  Also in this embodiment, when the shutter key is half-pressed again within 2 seconds from the release of the half-press of the shutter key, the multi-AF (step S508) is performed again, but the multi-AF is performed again. Instead, AF (step S510) may be performed by re-selecting the focus frame based on information by multi-AF performed in advance as in the above-described related art.

  In the present embodiment, when it is determined that it is within 2 seconds from the previous half-press release of the shutter key, that is, when the determination in step S503 is YES, the image comparison (step S504) and the threshold value are performed. The determination as to whether or not there is the above change (step S505) is performed. In the loop of steps S511 and S512, the comparison between the images (step S504) and the determination as to whether there is a change equal to or greater than the threshold value (step S505). S505) may be performed, and if there is a change equal to or greater than the threshold value, the entire AF frame display (step S506) may be performed to execute the multi-AF process (step S508).

10 Digital Camera 11 Lens Block 12 Motor 13 CPU
14 bus 15 timing generator 16 motor driver 17 strobe 18 CCD
19 Horizontal driver 20 Unit circuit 21 Image processing unit 22 SDRAM
23 LCD monitor 25 External memory 26 Flash memory 27 Key input unit 30 Microcomputer

Claims (3)

Multi-focal point detection means for detecting the focal point of the optical system for a plurality of focal point detection areas and acquiring focal point information;
Selection means for selecting any of the plurality of focus detection areas based on a plurality of focus information acquired by the multi-focus detection means;
Reoperation control means for reactivating the selection means in response to a predetermined operation;
Comparing means for comparing the subject image when the multi-focus detection means detects the focus for a plurality of focus detection areas and the subject image when the re-operation control means re-operates the selection means,
The re-operation control means includes
Based on the comparison result of the comparison means, when both the subject images change more than a predetermined threshold, any one of a plurality of focus detection areas including the focus detection area already selected by the selection means is used as the selection means. Let the selection means select one of the plurality of focus detection areas without changing the selection criteria of the focus detection area by the selection means,
Whether the selection means selects other focus detection areas other than the focus detection area already selected by the selection means when the two subject images have not changed more than a predetermined threshold based on the comparison result of the comparison means. Alternatively, the selection unit selects one of the plurality of focus detection areas after changing a selection criterion of the focus detection area by the selection unit. The computer that the camera has
Multi-focal point detection means for detecting the focal point of the optical system for a plurality of focal point detection areas and acquiring focal point information;
Selection means for selecting any of the plurality of focus detection areas based on a plurality of focus information acquired by the multi-focus detection means;
Reoperation control means for reactivating the selection means in response to a predetermined operation;
The multi-focal point detection unit functions as a comparison unit that compares the subject image when the focus is detected for a plurality of focus detection areas and the subject image when the re-operation control unit re-activates the selection unit,
The re-operation control means includes
Based on the comparison result of the comparison means, when both the subject images change more than a predetermined threshold, any one of a plurality of focus detection areas including the focus detection area already selected by the selection means is used as the selection means. Let the selection means select one of the plurality of focus detection areas without changing the selection criteria of the focus detection area by the selection means,
Whether the selection means selects other focus detection areas other than the focus detection area already selected by the selection means when the two subject images have not changed more than a predetermined threshold based on the comparison result of the comparison means. Alternatively, the selection unit selects one of the plurality of focus detection areas after changing a selection criterion of the focus detection area by the selection unit. A multi-focus detection step of detecting the focus of the optical system for a plurality of focus detection areas and acquiring focus information;
A selection step of selecting any of the plurality of focus detection areas based on a plurality of focus information acquired by the multi-focus detection step;
A re-operation control step for re-activating the selection step in response to a predetermined operation;
A comparison step of comparing a subject image when a focus is detected for a plurality of focus detection areas in the multi-focus detection step and a subject image when the selection step is re-activated in the re-operation control step;
The re-operation control step includes
Based on the comparison result of the comparison step, when the two subject images have changed by a predetermined threshold value or more, any of a plurality of focus detection areas including the focus detection area already selected by the selection step is selected in the selection step. Or select one of the plurality of focus detection areas in the selection step without changing the selection criterion of the focus detection area in the selection step,
Whether the selection step selects other focus detection areas excluding the focus detection area already selected in the selection step when the two subject images have not changed more than a predetermined threshold based on the comparison result of the comparison step. Alternatively, after changing a selection criterion of the focus detection area in the selection step, any of the plurality of focus detection areas is selected in the selection step.

Images