JP5239250B2 - Electronic camera - Google Patents

Description

  The present invention relates to an electronic camera.

  A technique for performing a so-called best shot selector (BSS) operation in which an electronic camera records an image selected from a plurality of continuously shot images is known (see Patent Document 1).

JP 11-136557 A

  In the conventional technique, an image having a high spatial frequency is selected, or an image taken when camera shake detected by a detection sensor is small is selected. For this reason, an image with the optimum focus adjustment state for the main subject may not be selected.

(1) An electronic camera according to a first aspect of the present invention includes an imaging device and focus detection that divides a subject luminous flux into two systems and detects defocus information based on a phase difference between two images formed by the two luminous fluxes. Storage means for storing a plurality of images acquired in time series by the image sensor within a predetermined time before and after the shooting instruction, and a plurality of defocus information acquired by the focus detection means at the time of image acquisition; , An image having a difference from an image acquired immediately before the shooting instruction is equal to or less than a predetermined value, and is stored in a recording medium from among the plurality of stored images based on the plurality of stored defocus information. Selecting means for selecting an image to be stored.
(2) An electronic camera according to a second aspect of the present invention includes an imaging device and a focus detection that divides a subject light beam into two systems and detects defocus information based on a phase difference between two images formed by the two light beams. Storage means for storing a plurality of images acquired in time series by the imaging device within a predetermined time before a shooting instruction, and a plurality of defocus information acquired by the focus detection means at the time of image acquisition; , An image having a difference from an image acquired immediately before the shooting instruction is equal to or less than a predetermined value, and is stored in a recording medium from among the plurality of stored images based on the plurality of stored defocus information. Selecting means for selecting an image to be stored.
(3) An electronic camera according to a third aspect of the present invention includes an image sensor and focus detection that divides a subject luminous flux into two systems and detects defocus information based on a phase difference between two images formed by the two luminous fluxes. Storage means for storing a plurality of images acquired in time series by the image sensor within a predetermined time before and after the shooting instruction, and a plurality of defocus information acquired by the focus detection means at the time of image acquisition; The difference between the display means for sequentially displaying the reproduced images of the plurality of images acquired in time series by the imaging device and the image corresponding to the reproduced image displayed on the display means at the time of the photographing instruction is a predetermined value. Selection means for selecting an image to be stored on a recording medium from the plurality of stored images based on the plurality of stored defocus information. .
(4) An electronic camera according to a fourth aspect of the present invention includes an image sensor and focus detection for dividing the subject light flux into two systems and detecting defocus information based on the phase difference between the two images formed by the two light fluxes. Storage means for storing a plurality of images acquired in time series by the imaging device within a predetermined time before a shooting instruction, and a plurality of defocus information acquired by the focus detection means at the time of image acquisition; The difference between the display means for sequentially displaying the reproduced images of the plurality of images acquired in time series by the imaging device and the image corresponding to the reproduced image displayed on the display means at the time of the photographing instruction is a predetermined value. Selecting means for selecting an image to be stored in a recording medium from among the plurality of stored images based on the plurality of stored defocus information.
(5) The electronic camera according to claim 5 is the electronic camera according to any one of claims 1 to 4, further comprising a release operation member that emits a signal of the imaging instruction, and the time series of the imaging device. Image acquisition and acquisition of defocus information by the focus detection means at the time of image acquisition are started in response to a half-press operation signal from the release operation member.
(6) An electronic camera according to a sixth aspect is the electronic camera according to any one of the first to fifth aspects, wherein an optical system for dividing the subject luminous flux into two systems is formed in the imaging device. Features.
(7) An electronic camera according to a seventh aspect is the electronic camera according to any one of the first to sixth aspects, wherein the selection means selects an image corresponding to the minimum defocus information.

  With the electronic camera according to the present invention, it is possible to select an image with the optimum focus adjustment state.

  The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram for explaining a main configuration of an electronic camera according to an embodiment of the present invention. The electronic camera is controlled by the control device 4.

  The taking lens 1 forms a subject image on an image pickup surface of an image pickup element to be described later. The distance measuring device and imaging device 3 includes an imaging device, an AFE (Analog Front End) circuit, an A / D conversion circuit, and a defocus amount calculation circuit.

  The image sensor is constituted by, for example, a CMOS image sensor 31 (FIG. 2). The image sensor 31 captures a subject image and outputs an analog image signal to the AFE circuit. The AFE circuit performs analog processing on the analog image signal (such as signal amplification in accordance with the instructed ISO sensitivity). The ISO sensitivity changes the imaging sensitivity (exposure sensitivity) within a predetermined range (for example, equivalent to ISO 50 to ISO 1000) in accordance with a sensitivity setting instruction from the control device 4. The imaging sensitivity is a controlled amount that changes the amplification factor of signal amplification performed by the AFE circuit. The imaging sensitivity value is represented by a corresponding ISO sensitivity value. The A / D conversion circuit converts the image signal after analog processing into a digital signal. The digital image signal is output to the image processing unit 4a in the control device 4.

  The image processing unit 4a performs image processing on the input digital image signal. Image processing includes, for example, γ conversion processing, contour enhancement processing, filter processing, color temperature adjustment (white balance adjustment) processing, format conversion processing for image signals, image compression / decompression processing, and the like. The buffer memory 4b temporarily stores data before and after image processing and during image processing, stores an image file before recording on the recording medium 9, and stores an image file read from the recording medium 9. Used for.

  The display circuit 6 creates display data for displaying a captured image on the liquid crystal monitor 7 and displaying an operation menu on the liquid crystal monitor 7. The liquid crystal monitor 7 displays a reproduced image or menu screen based on the created display data.

  The control device 4 inputs a signal output from each block, performs a predetermined calculation, and outputs a control signal based on the calculation result to each block. The operation member 8 includes operation switches for an electronic camera. The operation member 8 outputs an operation signal from each operation switch to the control device 4 such as a half-press switch, a full-press switch, a menu operation key, and the like that are turned on / off in conjunction with a pressing operation of a release button (not shown). .

  The recording medium 9 includes a memory card that can be attached to and detached from the electronic camera. In the recording medium 9, image data and an image file including the information are recorded according to an instruction from the control device 4. The image file recorded on the recording medium 9 can be read by an instruction from the control device 4.

<Focus detection processing>
The electronic camera according to the present embodiment detects a focus adjustment state by the photographing lens 1 using a light beam incident on a focus detection region on the image sensor 31 by a so-called phase difference detection method. FIG. 2 is a diagram for explaining pixel positions for focus detection formed in the image sensor 31. Among the pixels of the image sensor 31, a predetermined number of pixel rows arranged in the horizontal direction exemplified as the horizontal sensor 1 to the horizontal sensor 3, and three vertical directions exemplified as the vertical sensor 1 to the vertical sensor 3. Each of the predetermined number of pixel columns corresponds to a focus detection area. Masking for pupil division is performed on the pixels constituting these six sensor rows.

  Specifically, substantially half of the on-chip microlens formed corresponding to the pixel is shielded from light. FIG. 3 is an enlarged view of a pixel column constituting the lateral sensor. In each pixel, the left half or right half is masked alternately. Thereby, between the pixels adjacent in the horizontal direction, the half faces masked or the half faces not masked are adjacent to each other.

  FIG. 4 is an enlarged view of a pixel column constituting the vertical sensor. In each pixel, the upper half surface or the lower half surface is masked alternately. Thereby, half-masked or non-masked half-faces are adjacent to each other between pixels adjacent in the vertical direction.

  FIG. 5 is a diagram for explaining a pixel column constituting the lateral sensor and a light beam incident on the pixel column. In FIG. 5, a light beam (referred to as an A component) from the left direction enters a photodiode of a pixel whose right half surface is masked. A light beam (referred to as a B component) from the right direction is incident on the photodiode of the pixel whose left half surface is masked.

  As a result, the pixel output (photoelectric conversion signal value) obtained from the pixel group to which the A component light beam is incident represents an image by the light beam incident from one half of the exit pupil of the photographing lens 1, and the B component light beam is A pixel output (photoelectric conversion signal value) obtained from the incident pixel group represents an image of a light beam incident from the other half of the exit pupil.

  FIG. 6 is a diagram illustrating pixel output waveforms obtained when focusing on the main subject. In FIG. 6, the horizontal axis represents the pixel position, and the vertical axis represents the pixel output. Since a sharp image is formed on the image sensor 31 at the time of focusing, a pair of images formed by pupil-divided light beams coincide on the image sensor 31. That is, the A component waveform and the B component waveform obtained from the pixel group constituting the horizontal sensor (vertical sensor) overlap in shape.

  FIG. 7 is a diagram illustrating a pixel output waveform obtained when the main subject is out of focus. In FIG. 7, the horizontal axis represents the pixel position, and the vertical axis represents the pixel output. At the time of out-of-focus, a state where a sharp image is formed in front of the image sensor 31 or a state where a sharp image is formed on the back side of the image sensor 31, the pair of images formed by the pupil-divided light beams coincide on the image sensor 31. do not do. In this case, the A component waveform and the B component waveform have different positional relationships (shift direction and shift amount Δd) between the A component waveform and the B component waveform in accordance with the shift (defocus amount) from the focused state.

  A defocus amount calculation circuit in the distance measuring device / imaging device 3 calculates a focus position adjustment state (defocus amount) by the photographing lens 1 based on a positional relationship between the A component waveform and the B component waveform, and calculates the calculation result. It is sent to the control device 4. When the control device 4 outputs a lens drive signal (a signal for instructing the lens drive direction and the lens drive amount) according to the defocus amount to the lens drive mechanism 5, the lens drive mechanism 5 moves the focus lens 2 forward and backward in the optical axis direction. Let Thereby, focus adjustment is performed.

  Note that the comparison region illustrated in FIGS. 6 and 7 is a region that commonly includes feature points (for example, local maximum values) extracted from the A component waveform and the B component waveform. The defocus amount calculation circuit obtains the defocus amount using the waveform data in the comparison region among the A component waveform and B component waveform obtained from the pixel group constituting the horizontal sensor (vertical sensor).

<Best shot function>
The electronic camera of this embodiment has a best shot selector (BSS) function related to focus. When the focus best shot selector (FBSS) function is turned on by the menu operation, the control device 4 validates the FBSS function.

  FIG. 8 is a diagram for explaining the FBSS function. In FIG. 8, the horizontal axis represents the time axis. The electronic camera with the FBSS function enabled sequentially captures subject images at a predetermined frame rate (for example, 30 frames / second), and stores the image data in the buffer memory 4b. This image data is data (RAW) that has not been subjected to image processing. The electronic camera leaves the most recent predetermined number of image data (for example, six) in the buffer memory 4b and overwrites and deletes the old image data. “Image acquisition” in the figure represents imaging timing.

  The “release operation signal” in the figure represents the timing at which an operation signal indicating that the release button has been fully pressed is input to the control device 4. The electronic camera selects the image data with the smallest defocus amount from among a predetermined number of image data captured before the timing of the “release operation signal” and stored in the buffer memory 4b. In this embodiment, it is assumed that the focus adjustment is performed before the predetermined number of “image acquisition” illustrated in FIG. 8 is started.

  Specifically, among the image data stored in the buffer memory 4b, the pixel group data corresponding to the horizontal sensor (vertical sensor) is sent to the distance measuring device / imaging device 3, and the defocus amount is minimized. Identify the image to be. The control device 4 performs image processing on the specified image data in the image processing unit 4 a and stores a file including the image data after the image processing in the recording medium 9.

The flow of camera processing performed by the control device 4 when the above-described FBSS function is valid will be described with reference to the flowcharts of FIGS.
<Release standby processing>
In step S10 of FIG. 9, the control device 4 determines whether or not a half-press operation has been accepted. When an operation signal indicating that the release button has been half-pressed is input from the operation member 8, the control device 4 makes a positive determination in step S10 and proceeds to step S20. When the operation signal indicating that the release button has been half-pressed is not input from the operation member 8, the control device 4 makes a negative determination in step S10 and waits for the release while repeating the determination process.

  In step S20, the control device 4 performs phase difference detection AF (autofocus) processing and proceeds to step S30. Details of the phase difference detection AF processing will be described later. In step S30, the control device 4 performs a release initialization process and proceeds to step S40. Details of the release initialization process will be described later.

  In step S40, the control device 4 determines whether or not the half-press operation has been released. When the operation signal indicating that the release button is half-pressed is continuously input from the operation member 8, the control device 4 makes a negative determination in step S40 and proceeds to step S50. If the operation signal indicating that the release button has been pressed halfway is not input from the operation member 8, the control device 4 makes a positive determination in step S40 and returns to step S10.

  In step S50, the control device 4 performs a pre-release preparation process and proceeds to step S60. Details of the pre-release preparation process will be described later. In step S60, the control device 4 determines whether or not a release operation has been accepted. When an operation signal indicating that the release button has been fully pressed is input from the operation member 8, the control device 4 makes a positive determination in step S60 and proceeds to step S70. If the operation signal indicating that the release button has been fully pressed is not input from the operation member 8, the control device 4 makes a negative determination in step S60 and returns to step S40.

  In step S70, the control device 4 performs a release process and returns to step S10. Details of the release process will be described later.

<Phase difference detection AF processing>
In step S21 of FIG. 10, the control device 4 sends an instruction to the distance measuring device / imaging device 3 to acquire the AF sensor output, and the process proceeds to step S22. As a result, the distance measuring device / imaging device 3 captures the subject image. Of the acquired image data, pixel group data corresponding to the horizontal sensor (vertical sensor) corresponds to the AF sensor output.

  In step S22, the control device 4 sends an instruction to the distance measuring device / imaging device 3, detects the phase difference (calculates the defocus amount), and proceeds to step S23. In step S23, the control device 4 determines whether or not the phase difference has been detected. When the defocus information is received from the distance measuring device / imaging device 3, the control device 4 makes a positive determination in step S23 and proceeds to step S24. If the defocus information is not received from the distance measuring device / imaging device 3, the control device 4 makes a negative determination in step S23 and proceeds to step S28.

  In step S24, the control device 4 determines that phase difference detection AF is possible, and proceeds to step S25. In step S25, the control device 4 calculates the focusing lens position according to the phase difference (defocus amount), and proceeds to step S26. In step S26, the control device 4 sends an instruction to the lens driving mechanism 5, moves the focus lens 2, and proceeds to step S27.

  In step S27, the control device 4 determines whether or not lens driving is completed. When the control device 4 receives a signal indicating that the lens driving is completed from the lens driving mechanism 5, the control device 4 makes a positive determination in step S27, ends the processing of FIG. 10, and proceeds to step S30 of FIG. When the control device 4 does not receive a signal indicating that the lens driving is completed from the lens driving mechanism 5, the control device 4 makes a negative determination in step S27 and waits for the lens driving to be completed while repeating the determination processing.

  In step S28, which proceeds after making a negative determination in step S23, the control device 4 determines that phase difference detection AF is not possible, and proceeds to step S29. In step S29, the control device 4 calculates the lens position when it is impossible, and proceeds to step S26. The lens position when the phase difference detection AF is impossible is a lens position that is focused at a predetermined subject distance (for example, 2 m).

<Release initialization process>
In step S31 of FIG. 11, the control device 4 clears the image buffer, ends the process of FIG. 11, and proceeds to step S40 of FIG. Specifically, the data remaining in the image storage area in the buffer memory 4b is deleted.

<Pre-release preparation>
The pre-release preparation process corresponds to the image acquisition at the predetermined frame rate described as the focus best shot selector (FBSS) function. In step S51 of FIG. 12, the control device 4 sends an instruction to the distance measuring device / imaging device 3, sequentially captures the subject image, and proceeds to step S22. Accordingly, the distance measuring device / imaging device 3 performs “image acquisition” at the timing illustrated in FIG.

  In step S52, the control device 4 determines whether or not the image buffer has accumulated a predetermined number or more. When the number of stored images in the buffer memory 4b has reached a predetermined number (for example, 6), the control device 4 makes a positive determination in step S52 and proceeds to step S54. If the number of stored images in the buffer memory 4b has not reached the predetermined number, the control device 4 makes a negative determination in step S52 and proceeds to step S53.

  In step S53, the control device 4 accumulates the image data acquired by the distance measuring device / imaging device 3 in the buffer memory 4b, ends the processing in FIG. 12, and proceeds to step S60 in FIG.

  In step S54, which proceeds after making an affirmative decision in step S52, the control device 4 deletes the oldest image data in the buffer memory 4b and proceeds to step S53.

<Release processing>
The release process is a process performed in accordance with the “release operation signal” in FIG. In step S71 of FIG. 13, the control device 4 detects phase difference information from the image in the image buffer, and proceeds to step S72. Specifically, among the image data stored in the buffer memory 4 b, the pixel group data corresponding to the above-described horizontal sensor (vertical sensor) is sent to the distance measuring device / imaging device 3.

  In step S72, the control device 4 determines whether or not there is an image that can detect the phase difference. When the defocus information is received from the distance measuring device / imaging device 3, the control device 4 makes a positive determination in step S72 and proceeds to step S73. If the defocus information is not received from the distance measuring device / imaging device 3, the control device 4 makes a negative determination in step S72 and proceeds to step S75.

  In step S73, the control device 4 selects an image having the smallest phase difference from the images for which the phase difference has been detected, and proceeds to step S74. Specifically, the minimum defocus amount is selected from the defocus information received from the distance measuring device / imaging device 3. The control device 4 further selects an image including the pixel group data used for calculating the minimum defocus amount from the images stored in the buffer memory 4b.

  In step S74, the control device 4 performs image processing on the image data selected in the previous step by the image processing unit 4a, and saves the file containing the image data after the image processing in the recording medium 9 according to FIG. The process ends.

  In step S75, in which the determination is negative in step S72, the control device 4 selects the latest image from the images stored in the buffer memory 4b and proceeds to step S74.

According to the embodiment described above, the following operational effects can be obtained.
(1) Since the electronic camera includes the image sensor 31 including the pixel columns for pupil division (horizontal sensor 1 to horizontal sensor 3, vertical sensor 1 to vertical sensor 3) used for phase difference detection AF, the pupil is divided. A pair of images can be acquired on an imaging surface for acquiring a captured image. This prevents the occurrence of out-of-focus due to the fact that the imaging surface of the image sensor and the imaging surface of the focus sensor are not exactly the same as when the focus sensor used for phase difference detection AF is provided separately from the image sensor. be able to.

(2) The electronic camera sequentially captures the subject image at a predetermined frame rate, and stores the image data in the buffer memory 4b. Since the accumulated image data includes a pair of images that are pupil-divided for phase difference detection AF, defocus information can be acquired at the same timing as image acquisition.

(3) When the FBSS function is valid, the electronic camera selects, as a storage target, image data having a minimum defocus amount from among a predetermined number of image data that has been captured and stored in the buffer memory 4b. Thereby, an image with the smallest focus deviation can be stored in the recording medium 9.

(4) Image data to be stored is selected from a predetermined number of image data that have been captured before the timing of the “release operation signal” instructing the electronic camera to shoot and stored in the buffer memory 4b. If the predetermined number of images is reduced, only images acquired at a timing close to the timing of the “release operation signal” are candidates for saving, so it is possible to save images that are in focus while saving the so-called release time lag. it can.

(5) The electronic camera does not perform image processing on all of the predetermined number of image data stored in the buffer memory 4b, and the image processing unit 4a performs image processing only on the image data with the smallest defocus amount. It was made to process. As a result, the processing load can be reduced as compared with the case where image processing is performed on all images.

(Modification 1)
Image data to be saved from image data including images taken before the timing of the "release operation signal" as well as images taken before the timing of the "release operation signal" that instructs the electronic camera to shoot You may make it choose. FIG. 14 is a diagram illustrating the FBSS function according to the first modification. In FIG. 14, “release operation signal” represents the timing at which an operation signal indicating that the release button has been fully pressed is input to the control device 4. The control device 4 selects the image data with the smallest defocus amount from among a predetermined number of image data captured before and after the timing of the “release operation signal” and stored in the buffer memory 4b.

  Also in the case of the first modification, if the predetermined number is reduced, only images acquired at a timing close to the timing of the “release operation signal” are candidates for storage, so that the focus is achieved while suppressing the so-called release time lag. Images can be saved.

(Modification 2)
The image data to be stored may be selected in two stages. In the first selection, an image having a high degree of similarity to an image captured immediately before the “release operation signal” instructing the electronic camera to shoot is selected. In the second sorting, image data with the smallest defocus amount is selected from the images selected in the first sorting. FIG. 15 is a diagram illustrating the FBSS function according to the second modification. In FIG. 15, “release operation signal” represents the timing at which an operation signal indicating that the release button has been fully pressed is input to the control device 4. As the first selection, the control device 4 sequentially compares the image immediately before the “release operation signal” timing with a predetermined number of images stored in the buffer memory 4b.

  The control device 4 selects an image whose difference from the image data acquired immediately before the “release operation signal” is equal to or less than a predetermined value (three images in the example of FIG. 15), and selects from the data of the three selected images. Select the image data with the least defocus amount. The difference between the image data is calculated, for example, between corresponding pixel outputs for a predetermined range of pixel output values including the focus detection area. As a result, an image whose similarity is lowered by moving the main subject, closing the eyes, or passing another object between the electronic camera and the main subject may be excluded from the second selection target. it can.

(Modification 3)
When the FBSS function is enabled, reproduced images of images sequentially acquired by the distance measuring device / imaging device 3 may be sequentially displayed on the liquid crystal monitor 7. In this case, the control device 4 sends to the display circuit 6 data thinned out in accordance with the number of display pixels of the liquid crystal monitor 7 among the image data stored in the buffer memory 4b. As a result, the latest monitor image is displayed on the liquid crystal monitor 7.

  In the electronic camera of the third modification, the image (actually displayed on the liquid crystal monitor 7 at the timing of the “release operation signal” instructing the electronic camera to take a picture when performing the first selection as in the second modification. Selects an image having a high similarity to the image in the buffer memory 4b from which the display image is based. The second selection is the same as in the second modification. According to the third modification, when the photographer operates the release button while observing the monitor image displayed on the liquid crystal monitor 7, the image has a high similarity to the image intended by the photographer and is in focus. Can be saved.

  In the above description, the focus operation for moving the focus lens 2 according to the detected defocus amount is performed before the predetermined number of “image acquisition” is started. FIG. 16 is a diagram for explaining the FBSS function. In the case illustrated in FIG. 16, the “half-press operation signal” represents the timing at which an operation signal indicating that the release button has been half-pressed is input to the control device 4.

  In response to the half-press operation signal, the control device 4 sends the pixel group data corresponding to the above-described horizontal sensor (vertical sensor) to the distance measuring device / imaging device 3 among the latest image data acquired at that time. The feed and defocus amount are detected. The control device 4 further performs a focusing operation according to the detected defocus amount. Subsequent image acquisition is the same as in the case of FIG. 8 described above. By controlling in this way, the focus state obtained by the focusing operation during the half-press operation can be fixed until the release operation.

(Modification 4)
The focusing operation may be performed each time “image acquisition” is performed. FIG. 17 is a diagram for explaining the FBSS function. The control device 4 sends pixel group data corresponding to the above-described horizontal sensor (vertical sensor) to the distance measuring device / imaging device 3 among the latest image data, and detects the defocus amount. The control device 4 further performs a focusing operation according to the detected defocus amount. By controlling in this way, focusing can always be performed based on the latest defocus amount.

(Modification 5)
A configuration may be adopted in which a predetermined number of “image acquisitions” are repeated while the focus lens 2 is moved between the infinity (∞) end and the close end. FIG. 18 is a diagram for explaining the FBSS function. The control device 4 sends an instruction to the lens driving mechanism 5 to move the focus lens 2. Further, when the focus lens 2 starts to move, the control device 4 starts a predetermined number of “image acquisition”.

  By controlling in this way, images can be acquired at a predetermined number of focus lens positions, so that an image in which at least one image is focused on the main subject can be obtained. By selecting the image data with the smallest defocus amount from the predetermined number of image data stored in the buffer memory 4b, it is possible to save the focused image.

(Modification 6)
A focus sensor used for phase difference detection AF may be provided separately from the image sensor 31. Even when the focus sensor is provided separately, image acquisition is possible if the pair of images divided by the focus sensor is sequentially acquired in accordance with the timing of sequentially capturing the subject images to be accumulated in the buffer memory 4b. The defocus information can be acquired at the same timing as the above, and the present invention can be applied.

  In the above-described embodiment, as a pre-release preparatory process, a predetermined number of images are accumulated in the buffer memory 4b, and then an image selection process based on defocus information is performed on the image accumulated in the buffer memory 4b. Is going. However, the present invention is not limited to this, and the defocus information of the captured image is extracted before being stored in the buffer memory 4b, and the extracted defocus information is compared with the defocus information of the image already stored in the buffer memory 4b. Thus, it may be selected whether or not to store the image captured this time in the buffer memory 4b in place of the image already stored in the buffer memory 4b. If this method is adopted, only the best image selected based on the defocus amount comparison is always stored in the buffer memory 4b. As a result, the buffer memory 4b only needs to be able to store one image, so that it is possible to realize an image selection function based on the defocus amount while saving the capacity of the buffer memory 4b.

  The above description is merely an example, and is not limited to the configuration of the above embodiment. You may combine suitably embodiment and each modification which were mentioned above.

It is a block diagram explaining the principal part structure of the electronic camera by one embodiment of this invention. It is a figure explaining the pixel position for focus detection formed in an image sensor. It is an enlarged view of the pixel row which comprises a horizontal sensor. It is an enlarged view of the pixel row | line which comprises a vertical sensor. It is a figure explaining the light beam which enters into the pixel row | line which comprises a horizontal sensor, and a pixel row | line. It is a figure which illustrates the pixel output waveform obtained at the time of focusing. It is a figure which illustrates the pixel output waveform obtained at the time of non-focusing. It is a figure explaining an FBSS function. It is a flowchart explaining a release standby process. It is a flowchart explaining a phase difference detection AF process. It is a flowchart explaining a release initialization process. It is a flowchart explaining a pre-release preparation process. It is a flowchart explaining a release process. It is a figure explaining the FBSS function by the modification 1. It is a figure explaining the FBSS function by the modification 2. It is a figure explaining the case where the focus state obtained at the time of half-pressing operation is fixed until the time of release operation. It is a figure explaining the FBSS function of the modification 4. It is a figure explaining the FBSS function of the modification 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Shooting lens 2 ... Focus lens 3 ... Distance measuring device and imaging device 4 ... Control apparatus 4a ... Image processing part 4b ... Buffer memory 5 ... Lens drive mechanism 6 ... Display circuit 7 ... Liquid crystal monitor 8 ... Operation member 9 ... Recording medium

Claims (7)

An image sensor;
A focus detection unit that divides a subject light beam into two systems and detects defocus information based on a phase difference between two images formed by the two light beams;
Storage means for storing a plurality of images acquired in time series by the image sensor within a predetermined time before and after a shooting instruction, and a plurality of defocus information acquired by the focus detection means at the time of image acquisition;
An image whose difference from the most recently acquired image of the shooting instruction is a predetermined value or less, and is stored in a recording medium from among the plurality of stored images based on the plurality of stored defocus information An electronic camera comprising: selection means for selecting an image to be performed. An image sensor;
A focus detection unit that divides a subject light beam into two systems and detects defocus information based on a phase difference between two images formed by the two light beams;
Storage means for storing a plurality of images acquired in time series by the image sensor within a predetermined time before an imaging instruction and a plurality of defocus information acquired by the focus detection means at the time of image acquisition;
An image whose difference from the most recently acquired image of the shooting instruction is a predetermined value or less, and is stored in a recording medium from among the plurality of stored images based on the plurality of stored defocus information An electronic camera comprising: selection means for selecting an image to be performed. An image sensor;
A focus detection unit that divides a subject light beam into two systems and detects defocus information based on a phase difference between two images formed by the two light beams;
Storage means for storing a plurality of images acquired in time series by the image sensor within a predetermined time before and after a shooting instruction, and a plurality of defocus information acquired by the focus detection means at the time of image acquisition;
Display means for sequentially displaying reproduced images of the plurality of images acquired in time series by the imaging device;
The difference between the image corresponding to the reproduced image displayed on the display means at the time of the photographing instruction is an image having a predetermined value or less, and based on the stored defocus information, An electronic camera comprising: selection means for selecting an image to be stored in a recording medium from among the images. An image sensor;
A focus detection unit that divides a subject light beam into two systems and detects defocus information based on a phase difference between two images formed by the two light beams;
Storage means for storing a plurality of images acquired in time series by the image sensor within a predetermined time before an imaging instruction and a plurality of defocus information acquired by the focus detection means at the time of image acquisition;
Display means for sequentially displaying reproduced images of the plurality of images acquired in time series by the imaging device;
The difference between the image corresponding to the reproduced image displayed on the display means at the time of the photographing instruction is an image having a predetermined value or less, and based on the stored defocus information, An electronic camera comprising: selection means for selecting an image to be stored in a recording medium from among the images. In the electronic camera as described in any one of Claims 1-4,
A release operation member that emits a signal of the shooting instruction;
The time-series image acquisition by the image sensor and the acquisition of defocus information by the focus detection means at the time of image acquisition are started in response to a half-press operation signal from the release operation member. camera. In the electronic camera as described in any one of Claims 1-5,
An electronic camera, wherein an optical system that divides the subject light flux into two systems is formed in the imaging device. In the electronic camera as described in any one of Claims 1-6,
The electronic camera according to claim 1, wherein the selection means selects an image corresponding to minimum defocus information.

Images