JP2009089144A - Electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that it is difficult to detect a focus while displaying live view image conventionally in an electronic camera employing a solid-state imaging element with focus detecting pixel for pupil splitting, which is embedded therein. <P>SOLUTION: The electronic camera is provided with: a lens optical system equipped with a focus lens; the solid-state imaging element with a focus detecting pixel through pupil splitting phase shift system which is embedded therein; a display monitor; a control unit which thins and reads pixel signal out of the solid state imaging element to display the same on the display monitor so that the focus detecting pixel pupil-split in a row direction capable of detecting the focus of vertical line is included in the same row as the pixels of the solid state imaging element corresponding to the pixel displayed in the display monitor upon live-view monitoring at a real time while thinning the pixel signal obtained by the solid-state imaging element; and a phase shift focus control unit which detects the position of focus using the pixel signal of the pixel for detecting the focus which was read out of the solid-state imaging element and to control the position of the focus lens for the lens optical system. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic camera using a solid-state imaging device having a focus detection function.

  In recent years, video cameras and electronic cameras having an AF (autofocus) function have been widely used. These cameras use CCD-type or CMOS-type solid-state imaging devices, and a plurality of unit pixels having photoelectric conversion units that generate signal charges according to the amount of incident light are arranged in a two-dimensional matrix. ing. Also, on the side where the light of the photoelectric conversion unit is incident, a microlens is arranged on-chip so that light incident on the pixel unit other than the photoelectric conversion unit is condensed on the photoelectric conversion unit to increase the amount of light. It has become.

Conventionally, a contrast method has been adopted as a focus detection method using a solid-state imaging device, and a camera user equipped with an AF function using the same method does not look into the viewfinder and uses a small monitor provided on the back of the camera. It has become common to check the in-focus state by viewing the displayed live view image.
On the other hand, the pupil division phase difference method capable of high-speed focus detection used in a single-lens reflex camera or the like guides light to a dedicated focus detector arranged separately from the solid-state imaging device. For this reason, no light hits the solid-state imaging device during focus detection, and a live view image could not be confirmed. In view of this, a solid-state image sensor incorporating a focus detection function based on a pupil division phase difference method has also been proposed so that high speed can be achieved even with AF using the solid-state image sensor (see, for example, Patent Document 1).
JP 2003-244712 A

  Even when the focus detection function based on the pupil division phase difference method is incorporated in the solid-state imaging device and AF is speeded up, it is required that the in-focus state can be confirmed with the live view image from the viewpoint of user convenience. For this reason, it is necessary to perform both reading of an image signal for displaying a live view image and reading of a focus detection signal for performing focus detection.

On the other hand, since the live view image is displayed on a small monitor with low resolution mounted on the camera, the image data of all the pixels read from the solid-state image sensor is not displayed on the monitor as it is, but a few pixels are mixed. The display is displayed on the monitor after the resolution is reduced by processing such as processing or pixel thinning.
In addition, when a focus detection area based on the pupil division phase difference method is incorporated in a unit pixel, in order to perform focus detection in the vertical line direction, focus detection is performed by reading only a row with the focus detection areas arranged in the horizontal direction. Can be performed in a short time. However, CMOS-type solid-state imaging devices generally read one line at a time when reading signals from unit pixels arranged in a matrix in the matrix direction. Therefore, in order to perform focus detection in the horizontal line direction, the vertical direction is used. Since it is necessary to read out a plurality of rows including the focus detection areas arranged side by side, it takes time to detect the focus.

  As described above, the conventional technique has a problem that it is difficult to realize high-speed focus detection while displaying a live view image.

  In view of the above problems, an object of the present invention is to provide an imaging apparatus capable of simultaneously performing high-speed focus detection while displaying a live view image.

  An electronic camera according to the present invention includes a lens optical system including a focus lens, a solid-state imaging device incorporating a focus detection pixel based on a pupil division phase difference method, a display monitor, and a pixel signal acquired by the solid-state imaging device. When performing live view display in real time with thinning out, focus detection is performed by dividing the pupil in the row direction so that vertical lines can be detected in the same row as the pixels on the solid-state image sensor corresponding to the pixels displayed on the display monitor. A control unit that thins out and reads out a pixel signal from the solid-state imaging device so as to include a pixel and displays the pixel signal on the display monitor; and a focus position using the pixel signal of the focus detection pixel read out from the solid-state imaging device. And a phase difference focus control unit that detects and controls the position of the focus lens of the lens optical system.

  In particular, when the control unit reads out the rows from the solid-state imaging device, the focus detection pixels are not included in the thinned rows.

  Further, the phase difference focus control unit detects a focus position every time a pixel signal of the focus detection pixel is read out from the solid-state imaging device in units of rows, and controls the position of the focus lens of the lens optical system. It is characterized by that.

  In particular, the control unit includes a pixel signal of the focus detection pixel in a pixel displayed on the display monitor.

  Further, an electronic camera according to the present invention is obtained by a lens optical system including a focus lens, a solid-state imaging device incorporating a focus detection pixel by a pupil division phase difference method, a display monitor, and the solid-state imaging device. When the pixel signal is mixed in the row direction for live view display in real time, the vertical direction can be detected in the same row as the pixel on the solid-state image sensor corresponding to the pixel displayed on the display monitor. The focus detection pixels that are divided into pupils are included, and the focus detection pixels that are mixed are mixed with the pixel signals read from the solid-state imaging device so that the divided pupils are in the same direction. A focus position is detected using a control unit displayed on a monitor and a pixel signal of the focus detection pixel read from the solid-state image sensor, and the position of the focus lens of the lens optical system is detected. And having a phase difference focus control unit that controls.

  In particular, the solid-state imaging device includes a Bayer array RGB color filter, and the focus detection pixels are arranged in G filter pixels.

  In addition, an electronic camera according to the present invention includes a lens optical system including a focus lens, a solid-state imaging device incorporating a focus detection pixel based on a pupil division phase difference method, a display monitor, and the readout from the solid-state imaging device. A phase difference focus control unit that detects a focus position using a pixel signal of a focus detection pixel and controls the position of the focus lens of the lens optical system, and a pixel signal acquired by the solid-state image sensor is thinned out in real time. If the phase difference focus control unit does not perform focus control during live view display, the pixels on the solid-state imaging device corresponding to the pixels displayed on the display monitor are not included in the focus detection pixels. Read, when the phase difference focus control unit performs focus control, a vertical line in the same row as the pixels on the solid-state image sensor corresponding to the pixels displayed on the display monitor Characterized in that the read to include the focus detection pixels pupil splitting in the row direction can focus detection and a control unit for displaying on the display monitor.

  Further, an electronic camera according to the present invention is obtained by a lens optical system including a focus lens, a solid-state imaging device incorporating a focus detection pixel by a pupil division phase difference method, a display monitor, and the solid-state imaging device. When live view display is performed in real time by thinning out pixel signals, the pupil is divided in the row direction in which the vertical line focus can be detected in the same row as the pixels on the solid-state imaging device corresponding to the pixels displayed on the display monitor. A control unit that thins out and reads out a pixel signal from the solid-state image sensor so as to include a focus detection pixel and displays it on the display monitor, and a focus using the pixel signal of the focus detection pixel read out from the solid-state image sensor. Extracted from the phase difference focus control unit that detects the position and controls the position of the focus lens of the lens optical system, and the pixel signal output from the solid-state imaging device And contrast information, to accumulate and the focus lens position, and detects the focus position by the contrast method, and having a contrast focus control unit for controlling the position of the focus lens of the lens optical system.

  In particular, the contrast focus detection unit detects a focus position by a contrast method using the accumulated contrast information and focus lens position information when the phase difference focus detection unit does not complete focus detection within a predetermined time. The position of the focus lens of the lens optical system is controlled.

  According to the present invention, in an electronic camera having a focus detection function, a focus detection pixel based on the pupil division phase difference method is provided in the same row as a pixel to be displayed on the display monitor, thereby displaying the live view image on the display monitor. An image signal and a focus detection signal for performing focus detection can be obtained at a time, and high-speed focus detection can be performed while displaying a live view image.

Hereinafter, each embodiment will be described in detail with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram of an electronic camera 101 according to the first embodiment. The electronic camera 101 is a single-lens reflex camera including a camera body 102 and a lens optical system 103 that can be attached to and detached from the camera body 102.

  The camera body 102 includes a solid-state imaging device 104, a signal processing unit 105, a control unit 106, a liquid crystal display unit 107, a memory card 108, a lens driving unit 109, an operation panel 110, and a memory 111. The

  Subject light incident from the lens optical system 103 forms an image on the light receiving surface of the solid-state image sensor 104. On the light-receiving surface of the solid-state image sensor 104, a plurality of unit pixels having photoelectric conversion units in the row direction and the column direction are arranged in a matrix. The image signal photoelectrically converted by each unit pixel is read out to the signal processing unit 105 by a timing signal given from the control unit 106 to the solid-state imaging device 104. At this time, the control unit 106 reads out the image signal from the solid-state imaging device 104 to the signal processing unit 105 in units of rows.

  The signal processing unit 105 includes an image processing unit 112 and a focus detection processing unit 113. The image processing unit 112 performs noise removal processing, white balance processing, color interpolation processing, and the like on the image signal read from the solid-state imaging device 104 and outputs the processed signal to the control unit 106. Further, the focus detection processing unit 113 obtains a defocus amount from the focus detection signal read from the solid-state image sensor 104 and outputs the defocus amount to the control unit 106. Note that the electronic camera 101 according to the present embodiment can perform AF control by the pupil division method. For this reason, focus detection pixels are embedded in the solid-state imaging device 104, and the control unit 106 reads a focus detection signal from the focus detection pixels and inputs the focus detection signal to the focus detection processing unit 113.

  The control unit 106 operates according to a program stored in advance, and displays an image processed by the image processing unit 112 of the signal processing unit 105 on the liquid crystal display unit 107. Alternatively, it is temporarily stored in the memory 111 or stored in the memory card 108 in response to an operation from the operation panel 110. In addition, the control unit 106 instructs the lens driving unit 109 to move the focus lens of the lens optical system 103 to the in-focus position according to the defocus amount obtained by the focus detection processing unit 113 of the signal processing unit 105.

  The operation panel 110 includes operation buttons (release button, zoom button, etc.) and operation switches (power switch, etc.) for the user to operate the entire electronic camera 101, and the operation content is input to the control unit 106. The control unit 106 controls each unit of the electronic camera 101 according to the operation content.

  Next, the configuration of the solid-state image sensor 104 will be described with reference to FIG. FIG. 2 is a diagram illustrating a pixel arrangement (24 columns C1 to C24 and 12 rows R1 to R12) of a part of the light receiving surface of the solid-state imaging device 104.

  In FIG. 2, there are four rows R1, R4, R7, and R10 for live view display on the liquid crystal display unit 107. It should be noted that a portion that is not shown in the drawing is also displayed in a live view on the liquid crystal display unit 107 by reading out one row and thinning out two rows. In addition, the columns to be displayed in live view on the liquid crystal display unit 107 are eight columns of column C1, column C2, column C7, column C8, column C13, column C14, column C19, and column C20. In addition, it corresponds to four rows of row R1, row R4, row R7, and row R10 of FIG. 2, and eight columns of column C1, column C2, column C7, column C8, column C13, column C14, column C19, and column C20. The pixels for live view display are the parts surrounded by thick lines. In addition, a portion not shown in the figure is also displayed on the liquid crystal display unit 107 in a live view by reading out two columns and thinning out four columns in the same manner. Rows R2, R3, R5, R6, R8, R9, R11, and R12 other than the above are rows that are not displayed in live view. Similarly, columns C3 to C6, columns C9 to C12, columns C15 to C18, and columns C21 to C24 are also columns that are not displayed in live view.

  For example, in row R1, pixel (R1, C1), pixel (R1, C2), pixel (R1, C7), pixel (R1, C8), pixel (R1, C13), pixel (R1, C14), pixel ( R1, C19) and pixels (R1, C20) are displayed in live view on the liquid crystal display unit 107. In row R4, the pixels (R4, C1), pixels (R4, C2), pixels (R4, C7), pixels (R4) , C8), pixels (R4, C13), pixels (R4, C14), pixels (R4, C19), and pixels (R4, C20) are displayed in live view on the liquid crystal display unit 107.

  In FIG. 2, pixels indicated by shading indicate image pixels, and pixels on which characters a, b, a ′, and b ′ are written are focus detection pixels.

  Here, the image pixel and the focus detection pixel will be described with reference to FIG. 3A shows an image pixel 201, FIG. 3B shows a focus detection pixel 204 on the left side of the pupil division, and FIG. 3C shows a focus detection pixel 207 on the left side of the pupil division. . In the image pixel 201, the photoelectric conversion unit 202 is largely arranged at the center of the microlens 203 and the image pixel 201. On the other hand, in the focus detection pixel 204, the photoelectric conversion unit 205 is arranged in the left half of the microlens 206 and the image pixel 204. In the focus detection pixel 207, the photoelectric conversion unit 208 is disposed in the right half of the microlens 209 and the image pixel 207. The focus detection pixel 204 and the focus detection pixel 207 are paired and pupil-divided. The focus detection pixels indicated by a and b ′ in FIG. 2 are focus detection pixels on the left side of the pupil division, as in the image pixel 204 in FIG. 3, and the focus detection pixels indicated by a ′ and b are Similarly to the image pixel 207 in FIG. 3, it is a focus detection pixel on the right side of the pupil division.

  In FIG. 2, the focus detection pixels in the row R1 are pupil-divided as a pair of focus detection pixels a located in the pixels (R1, C1) and focus detection pixels b located in the pixels (R1, C7). The Similarly, the focus detection pixel a located at the pixels (R1, C13) and the focus detection pixel b located at the pixels (R1, C19) are pupil-divided as a pair. In the focus detection pixels in the row R4, the focus detection pixel a 'located in the pixel (R4, C2) and the focus detection pixel b' located in the pixel (R4, C8) are pupil-divided as a pair. Similarly, the focus detection pixel a 'positioned at the pixel (R4, C14) and the focus detection pixel b' positioned at the pixel (R4, C20) are pupil-divided as a pair. In row R7, pixels corresponding to the same column as row R1 are focus detection pixels, and in row R10, pixels corresponding to the same column as row R4 are focus detection pixels.

  Note that the focus detection processing unit 113 of the electronic camera 101 according to the present embodiment performs focus detection processing each time a row is read, and obtains a defocus amount in that row. For example, when the row R1 is read, focus detection processing by pupil division is performed using the pair of focus detection pixels a and focus detection pixels b. Similarly, when the row R4 is read, focus detection processing by pupil division is performed using the pair of focus detection pixels a 'and focus detection pixels b'.

  Further, as shown in FIG. 4, the solid-state imaging device 104 has a Bayer array color filter. In the Bayer array, for example, a G (green) filter and a B (blue) filter are alternately arranged in a row R1 as GBGB ..., and in the next row R2, R (... Red (red) filters and G (green) filters are alternately arranged. Similarly, in the rows R3 to R6 and below, the odd-numbered rows are provided with G and B color filters, and the even-numbered rows are provided with R and G color filters. 4, the same reference numerals as those in FIG. 2 indicate the same rows and columns as those in FIG. Accordingly, the focus detection pixels a, b, a ′, and b ′ in FIG. 2 are all arranged at the pixel positions of the G filter.

  Further, the color of the color filter of the pixel to be displayed in the live view on the liquid crystal display unit 107 is pixel (R1, C1), pixel (R1, C7), pixel (R1, C13), pixel (R1, C19) in row R1. Is a G filter, and pixels (R1, C2), pixels (R1, C8), pixels (R1, C14), and pixels (R1, C20) are B filters. In the row R4, the pixel (R4, C1), the pixel (R4, C7), the pixel (R4, C13), and the pixel (R4, C19) are R filters, and the pixel (R4, C2), pixel (R4, C8), Pixels (R4, C14) and pixels (R4, C20) are G filters. In this way, the pixels for live view display surrounded by the thick line in FIG. 2 are also arranged in the Bayer array as shown in FIG. 4, so that the color tone of the subject is the same as before thinning and displayed on the liquid crystal display unit 107 in live view. The

  Here, in the present embodiment, the focus detection pixels a, b, a ′, and b ′ in FIG. 2 are used for focus detection processing by the focus detection processing unit 113 and are also G filter pixels by the image processing unit 112. Used for live view display.

  As described above, since the electronic camera 101 according to the present embodiment includes the focus detection pixels based on the pupil division phase difference method in the same row as the image pixels displayed on the liquid crystal display unit 107, it is displayed as a live view image. The image signal to be displayed on the monitor and the focus detection signal for performing focus detection can be obtained by reading out one row, and high-speed focus detection processing can be performed while displaying the live view image.

  In this embodiment, focus detection processing is performed each time a row is read. However, after a plurality of rows or one screen is read, the focus position is controlled in combination with the defocus amount of different rows. It doesn't matter.

(Second Embodiment)
Next, an electronic camera 101 according to the second embodiment will be described. The configuration of the electronic camera 101 according to the second embodiment is basically the same as the block diagram of the electronic camera 101 of FIG. 1 of the first embodiment. This embodiment is different from the first embodiment in the solid-state imaging device 104, and the arrangement of focus detection pixels is different.

  Here, the arrangement of the pixels of the solid-state imaging device 104a of the present embodiment will be described with reference to FIG. FIG. 5 is a diagram showing a pixel arrangement (24 columns C1 to C24 and 12 rows R1 to R12) of a part of the light receiving surface of the solid-state imaging device 104a.

  In FIG. 5, the rows to be displayed in live view on the liquid crystal display unit 107 are pixels surrounded by bold lines in four rows R1, R4, R7, and R10. It should be noted that a portion that is not shown in the drawing is also displayed in a live view on the liquid crystal display unit 107 by reading out one row and thinning out two rows. Further, the columns of pixels used for live view display on the liquid crystal display unit 107 are all the columns C1 to C24. Rows R2, R3, R5, R6, R8, R9, R11, and R12 other than the above are rows that are not displayed in live view.

  Similarly to the solid-state image sensor 104, the solid-state image sensor 104a has the Bayer array color filter shown in FIG. Accordingly, the focus detection pixels a, b, a ′, and b ′ in FIG. 5 are all arranged at the G filter pixel positions as in FIG. 2 of the first embodiment.

  Next, the pixel mixing process, which is a feature of the present embodiment, will be described. In the first embodiment, the pixels for live view display on the liquid crystal display unit 107 and the pixels read out by thinning out from the solid-state imaging device 104 correspond one-to-one. However, in the present embodiment, a plurality of pixels in the row direction are used. A pixel mixing process for mixing pixels by color is performed.

  For example, when the control unit 106 reads out the row R1 from the solid-state imaging device 104a to the image processing unit 112 of the signal processing unit 105, the image processing unit 112 includes three pixels, a pixel in column C1, a pixel in column C3, and a pixel in column C5. The pixel data is mixed to obtain a focus detection signal for the focus detection pixel a for one pixel and a G pixel image signal for one pixel for live view display on the liquid crystal display unit 107.

  Similarly, in the row R1, the image processing unit 112 mixes three pieces of pixel data of the pixel in the column C2, the pixel in the column C4, and the pixel in the column C6, and the B pixel for one pixel to be displayed in the live view on the liquid crystal display unit 107. An image signal is obtained. The same applies to the columns C13 to C18.

  As an example of pixel mixture, there is a method of obtaining an average value of three pixel data. Alternatively, among the three pixels, the center pixel may be weighted to 0.5 and the pixels on both sides may be weighted and added to 0.25.

  Further, in the row R1, the image processing unit 112 mixes three pixel data of the pixel in the column C7, the pixel in the column C9, and the pixel in the column C11, a focus detection signal for the focus detection pixel b for one pixel, and the liquid crystal An image signal of one G pixel for live view display on the display unit 107 is obtained.

  Similarly, in the row R1, the image processing unit 112 mixes three pixel data of the pixel in the column C8, the pixel in the column C10, and the pixel in the column C12, and the B pixel corresponding to one pixel to be displayed in the live view on the liquid crystal display unit 107. An image signal is obtained. The same applies to the columns C19 to C24.

  In this way, in the row R1, using the columns C1 to C6 and the columns C13 to C18, the focus detection signals of the focus detection pixels a and the G pixels and B pixels to be displayed live on the liquid crystal display unit 107 are displayed. An image signal can be obtained, and using the columns C7 to C12 and columns C19 to C24, the focus detection signal of the focus detection pixel b and the images of the G pixel and the B pixel to be displayed in live view on the liquid crystal display unit 107 Signal. At this time, the focus detection pixel a mixes the focus detection pixels a in the same direction for pupil division, and the focus detection pixel b mixes the focus detection pixels b in the same direction for pupil division. As in the first embodiment, focus detection can be performed by the pupil division method. The same applies to the row R7.

  On the other hand, in the row R4, the image processing unit 112 mixes three pixel data of the pixel in the column C1, the pixel in the column C3, and the pixel in the column C5, and R pixels for one pixel to be displayed in live view on the liquid crystal display unit 107. The image signal is obtained.

  Similarly, in the row R4, the image processing unit 112 mixes three pixel data of the pixel in the column C2, the pixel in the column C4, and the pixel in the column C6 in the row R4, and performs focus detection of the focus detection pixel a ′ for one pixel. And a G pixel image signal for one pixel for live view display on the liquid crystal display unit 107. The same applies to the columns C13 to C18.

  Further, in the row R4, the image processing unit 112 mixes three pieces of pixel data of the pixel in the column C7, the pixel in the column C9, and the pixel in the column C11, and an image of R pixels for one pixel displayed on the liquid crystal display unit 107 for live view display. Get a signal.

  Similarly, in the row R4, the image processing unit 112 mixes the three pixel data of the pixel in the column C8, the pixel in the column C10, and the pixel in the column C12, and the focus detection signal of the focus detection pixel b ′ for one pixel is obtained. Then, a G pixel image signal for one pixel for live view display on the liquid crystal display unit 107 is obtained. The same applies to the columns C19 to C24.

  In this way, in the row R4, using the columns C1 to C6 and the columns C13 to C18, the focus detection signal of the focus detection pixel a ′ and the R pixel and the G pixel that are displayed in a live view on the liquid crystal display unit 107. Image signals, and using the columns C7 to C12 and columns C19 to C24, the focus detection signals of the focus detection pixels b ′ and the R and G pixels for live view display on the liquid crystal display unit 107. The image signal can be obtained. At this time, the focus detection pixel a ′ mixes the focus detection pixels a ′ in the same direction for pupil division, and the focus detection pixel b ′ mixes the focus detection pixels b ′ in the same direction for pupil division. Therefore, focus detection can be performed by the pupil division method as in the first embodiment. The same applies to the row R10.

  As described above, a focus detection signal that is a pair of pupil divisions is obtained from the focus detection pixel a and the focus detection pixel b from the row R1, and at the same time, image data of the G pixel and image data of the B pixel. And are obtained alternately. Further, a focus detection signal that is a pair of pupil divisions is obtained from the focus detection pixel a ′ and the focus detection pixel b ′ from the row R4, and at the same time, the image data of the R pixel and the image data of the G pixel are alternated. Is obtained. As a result, the pixels displayed in the live view display on the liquid crystal display unit 107 in the rows R1 and R4 have the Bayer arrangement as shown in FIG. 4, so that the color tone of the subject remains the same as before the thinning, and the live view is displayed on the liquid crystal display unit 107. An image is displayed.

  As described above, since the electronic camera 101 according to the present embodiment includes the focus detection pixels based on the pupil division phase difference method in the same row as the image pixels displayed on the liquid crystal display unit 107, it is displayed as a live view image. The image signal to be displayed on the monitor and the focus detection signal for performing focus detection can be obtained by reading out one row, and high-speed focus detection processing can be performed while displaying the live view image. In particular, in the present embodiment, since pixel mixing is performed to mix data of a plurality of pixels, the SN ratio is improved, and the image quality and focus detection accuracy of an image displayed in live view are improved. Further, since the focus detection pixels are a mixture of focus detection pixels in the same direction for pupil division, focus detection can be performed by the pupil division method as in the first embodiment.

  As in the first embodiment, the focus detection process may be performed each time a row is read out, and after a plurality of rows or one screen is read out, the defocus amounts of different rows may be combined. The focal position may be controlled.

(Third embodiment)
Next, an electronic camera 101 according to the third embodiment will be described. The configuration of the electronic camera 101 according to the third embodiment is basically the same as the block diagram of the electronic camera 101 of FIG. 1 of the first embodiment. This embodiment is different from the first embodiment in the solid-state imaging device 104, and the arrangement of focus detection pixels is different.

  Here, the arrangement of the pixels of the solid-state imaging device 104b of the present embodiment will be described with reference to FIG. FIG. 6 is a diagram showing a pixel arrangement (24 columns C1 to C24 and 12 rows R1 to R12) of a part of the light receiving surface of the solid-state imaging device 104b.

  In FIG. 6, there are four rows R1, R4, R7, and R10 for live view display on the liquid crystal display unit 107. In addition, the columns to be displayed in live view on the liquid crystal display unit 107 are eight columns of column C1, column C2, column C7, column C8, column C13, column C14, column C19, and column C20. In addition, it corresponds to four rows of row R1, row R4, row R7, and row R10 of FIG. 6, and eight columns of column C1, column C2, column C7, column C8, column C13, column C14, column C19, and column C20. The pixels for live view display are the parts surrounded by thick lines. It should be noted that a portion not shown in the figure is also displayed in the live view on the liquid crystal display unit 107 by reading out two columns and thinning out four columns in the same manner. Rows R2, R3, R5, R6, R8, R9, R11, and R12 other than the above are rows that are not displayed in live view. Similarly, columns C3 to C6, columns C9 to C12, columns C15 to C18, and columns C21 to C24 are also columns that are not displayed in live view.

  For example, in row R1, pixel (R1, C1), pixel (R1, C2), pixel (R1, C7), pixel (R1, C8), pixel (R1, C13), pixel (R1, C14), pixel ( R1, C19) and pixels (R1, C20) are displayed in live view on the liquid crystal display unit 107. In row R4, the pixels (R4, C1), pixels (R4, C2), pixels (R4, C7), pixels (R4) , C8), pixels (R4, C13), pixels (R4, C14), pixels (R4, C19), and pixels (R4, C20) are displayed in live view on the liquid crystal display unit 107.

  In FIG. 6, pixels indicated by shading indicate image pixels, and pixels on which characters a, b, a ′, and b ′ are written are focus detection pixels.

  Further, like the solid-state image sensor 104, the solid-state image sensor 104b has the Bayer array color filter shown in FIG. Accordingly, the focus detection pixels a, b, a ′, and b ′ in FIG. 6 are different from those in FIG. 2 in the first embodiment, but are all arranged at the pixel position where the G filter is located.

  Next, features of the present embodiment will be described. In the first embodiment and the second embodiment, the pixels for live view display are included in the liquid crystal display unit 107 in the focus detection pixels. However, in the present embodiment, the liquid crystal display unit is used when focus detection is not performed. Control is performed so that the pixel for live view display in 107 does not include the focus detection pixel. For example, when the release button of the operation panel 110 is half-pressed, the pixel data in the row direction is read so as to include the focus detection pixel, and when the release button is not half-pressed, the focus detection pixel is included. Read out the pixel data in the row direction so that there is no.

  In FIG. 6, the focus detection pixels are the focus detection pixels a in the columns C3, C9, C15, and C21 and the focus detection pixels b in the columns C5, C11, C17, and C23 in the row R1. The row R7 is the same as the row R1. In the row R4, the focus detection pixels a 'in columns C4, C10, C16, and C22, and the focus detection pixels b' in columns C6, C12, C18, and C24. The row R10 is the same as the row R4.

  Here, processing when the readout of the focus detection pixels is controlled in accordance with the half-press operation of the release button will be described with reference to the flowchart of FIG. The flowchart in FIG. 7 shows processing after the electronic camera 101 starts shooting.

  (Step S301) The user turns on the power switch of the operation panel 110 of the electronic camera 101 so that the user can take a picture. In this state, light from the subject incident from the lens optical system 103 is projected onto the light receiving surface of the solid-state image sensor 104.

  (Step S <b> 302) The control unit 106 reads out the image signal of the image pixel from the solid-state imaging device 104 to the image processing unit 112.

  (Step S <b> 303) The control unit 106 inputs the image processed by the image processing unit 112 and displays a live view image on the liquid crystal display unit 107. At this time, the image to be displayed is an image read from the image pixels thinned out in the row direction and the column direction as described with reference to FIG.

  (Step S304) It is determined whether or not the user has pressed the release button of the operation panel 110 halfway. If the release button is not half-pressed, the process returns to step S302. If the release button is half-pressed, the process proceeds to step S305.

  (Step S305) The control unit 106 reads out the image signal of the image pixel from the solid-state imaging device 104 to the image processing unit 112, and as described with reference to FIG. 6, the focus detection pixels a, b, a ′, b ′. The focus detection signal is read out to the focus detection processing unit 113.

  (Step S306) Similar to step S303, the control unit 106 inputs the image processed by the image processing unit 112 and displays the live view image on the liquid crystal display unit 107.

  (Step S307) The focus detection processing unit 113 obtains the defocus amount from the focus detection signals of the focus detection pixels a, b, a ′, and b ′ read from the solid-state imaging device 104, and outputs the defocus amount to the control unit 106. . At this time, the focus detection signals of the focus detection pixels a, b, a ′, and b ′ read out by the focus detection processing unit 113 are the pair of focus detection pixels a and b or the pair of focus detection pixels. A defocus amount is obtained for each pixel a ′ and b ′.

  (Step S308) The control unit 106 instructs the lens driving unit 109 to move the focus lens position of the lens optical system 103 according to the defocus amount obtained by the focus detection processing unit 113. After the processing, the process returns to step S304, and the same operation is repeated until the power switch of the operation panel 110 of the electronic camera 101 is turned off.

  As described above, in a state where the release button is not half-pressed, the control unit 106 receives the image signal from the image pixels in the columns C1, C2, C7, C8, C13, C14, C19, and C20 in the row R1. The data is read to 112 and displayed on the liquid crystal display unit 107 as a live view. For the rows R4, R7, and R10, image data is read from the image pixels in the same column as the row R1. Thus, in a state where the release button is not half-pressed, the control unit 106 does not read any focus detection signal of the focus detection pixels a, b, a ′, and b ′.

  When the release button is half-pressed, the control unit 106 reads the image signal from the image pixels in the columns C1, C2, C7, C8, C13, C14, C19, and C20 to the image processing unit 112 in the row R1. At the same time, focus detection signals are read out to the focus detection processing unit 113 from the columns C3, C5, C9, C11, C15, C17, C19, C21, and C23 having the focus detection pixels a and b in the same row. The row R7 is read in the same manner as the row R1. Further, in the row R4, the control unit 106 reads out the image signal from the image pixels in the columns C1, C2, C7, C8, C13, C14, C19, and C20 to the image processing unit 112 and simultaneously detects the focus in the same row. A focus detection signal is read out to the focus detection processing unit 113 from the columns C4, C6, C10, C12, C16, C18, C20, C22, and C24 having the pixels a ′ and b ′. The row R10 is read in the same manner as the row R4.

  In the present embodiment, only the columns with the focus detection pixels a, b, a ′, and b ′ are read out, but the pixels in all the columns for one row may be read out. In this case, the signal processing unit 105 performs processing for separating the pixels for live view display and the focus detection pixels, and discards unnecessary pixels. For example, in the case of row R1 in FIG. 6, the data of each pixel in columns C4, C6, C10, C12, C16, C18, C22, and C24 are discarded.

  Further, in the case of this embodiment, since it is necessary to read out the focus detection pixels in addition to the pixels for live view display, the processing time is longer than that in the first embodiment, and when the live view display is performed accordingly. It is necessary to lower the frame rate. However, in the present embodiment, the focus detection pixels a, b, a ′, and b ′ are arranged in the same row as the pixels for live view display, and thus the rows R2, R3, R5, R6, and R8 that do not need to be read out. , R9, R11, and R12 can be thinned out, and high-speed processing is possible as compared with the case where focus detection pixels are arranged in a different row from the pixels for live view display.

  As described above, since the electronic camera 101 according to the present embodiment includes the focus detection pixels based on the pupil division phase difference method in the same row as the image pixels displayed on the liquid crystal display unit 107, it is displayed as a live view image. The image signal to be displayed on the monitor and the focus detection signal for performing focus detection can be obtained by reading out one row, and high-speed focus detection processing can be performed while displaying the live view image. In particular, in this embodiment, the focus detection signal is read from the focus detection pixel only when the focus detection operation is performed, and when the focus detection operation is not performed, only the image pixel is read without reading the focus detection pixel. Since live view display is performed on the liquid crystal display unit 107, a high-quality live view image can be displayed.

  As in the first embodiment, the focus detection process may be performed each time a row is read out, and after a plurality of rows or one screen is read out, the defocus amounts of different rows may be combined. The focal position may be controlled.

(Fourth embodiment)
Next, an electronic camera 101 according to the fourth embodiment will be described. The configuration of the electronic camera 101 according to the fourth embodiment is basically the same as the block diagram of the electronic camera 101 of FIG. 1 of the first embodiment. This embodiment is different from the first to third embodiments in that it also has AF control by a contrast method.

  In this embodiment, in FIG. 1, the control unit 106 serves as a contrast focus control unit, and the image processing unit 112 extracts contrast information from the pixel signal read from the solid-state imaging device 104 and outputs the contrast information to the control unit 106. As a method for extracting contrast information, for example, there is a method for obtaining a contrast value of a predetermined region by converting each RGB color into a gray scale.

  The control unit 106 stores the contrast information obtained by the image processing unit 112 in association with the focus lens position obtained from the lens driving unit 109 in the memory 111. In addition, when storing in the memory 111, there is a storage method such as a ring buffer for overwriting information after a predetermined period with new information so that information of the latest predetermined period (for example, 1 second) is always recorded. desirable.

  Here, the process of this embodiment is demonstrated using the flowchart of FIG. The flowchart in FIG. 8 shows AF control processing of the electronic camera 101. In this embodiment, focus detection control by the pupil division method of any one of the first to third embodiments is performed in parallel, and the control unit 106 has the focus detection processing unit 113 within a predetermined time. If the desired defocus amount does not become a predetermined value even when the lens driving unit 109 is driven to change the position of the focus lens, that is, if focus detection is not completed within a predetermined time, the defocus amount is stored in the memory 111 at that time. The focus position by the contrast method is detected using the information on the contrast information and the focus lens position, and the focus lens position of the lens optical system 103 is controlled.

  Hereinafter, the AF control process will be described in order.

  (Step S401) When the user half-presses the release button on the operation panel 110 of the electronic camera 101 from the shooting state, AF control is started.

  (Step S402) The control unit 106 reads out the image signal of the image pixel from the solid-state imaging device 104 to the image processing unit 112, and as described in FIG. 6, the focus detection pixels a, b, a ′, b ′. The focus detection signal is read out to the focus detection processing unit 113.

  (Step S403) The control unit 106 inputs the image processed by the image processing unit 112, and displays a live view image on the liquid crystal display unit 107. At this time, the image processing unit 112 extracts contrast information from the input image signal.

  (Step S <b> 404) The focus detection processing unit 113 obtains the defocus amount from the focus detection signals of the focus detection pixels a, b, a ′, and b ′ read from the solid-state imaging device 104 and outputs the defocus amount to the control unit 106. .

  (Step S405) The control unit 106 instructs the lens driving unit 109 to move the focus lens position of the lens optical system 103 in accordance with the defocus amount obtained by the focus detection processing unit 113.

  (Step S406) The control unit 106 acquires the focus lens position of the lens optical system 103 via the lens driving unit 109, and stores it in the memory 111 together with the contrast information extracted by the image processing unit 112 in step S403.

  (Step S407) The control unit 106 determines whether or not the in-focus state is obtained from the defocus amount obtained by the focus detection processing unit 113. If it is in focus, the process returns to step S402. If it is not in focus, the process proceeds to step S408.

  (Step S408) It is determined whether or not a predetermined time has elapsed since the start of AF control. If the predetermined time has not elapsed, the process returns to step S402, and if the predetermined time has elapsed, the process proceeds to step S409. The determination of the predetermined time is performed using a counter, and the counter is reset before the process proceeds to step S409 after the predetermined time has elapsed.

  (Step S409) The control unit 106 detects the in-focus position by the contrast method using the information on the contrast information and the focus lens position stored in the memory 111. The focus position detection by the contrast method uses a general hill climbing method.

  (Step S410) The control unit 106 instructs the lens driving unit 109 to move the focus lens position of the lens optical system 103 to the in-focus position obtained in step S409.

  As described above, when the electronic camera 101 according to this embodiment performs AF control, the pupil detection method focus detection process and the contrast method focus detection process described in the first to third embodiments are used in combination. Therefore, when the focus detection process by the pupil division method does not end within a predetermined time, the focus detection process by the contrast method can be performed. In particular, the focus lens position and contrast information necessary for the contrast method are accumulated during focus detection processing using the pupil division method, so the focus detection by the contrast method is performed immediately after switching from the pupil division method to the contrast method. Processing can be performed.

  As described above, in each embodiment, the electronic camera 101 according to the present invention is provided with focus detection pixels based on the pupil division phase difference method in the same row as the image pixels displayed on the liquid crystal display unit 107. Therefore, it is possible to obtain an image signal to be displayed on a display monitor as a live view image and a focus detection signal for performing focus detection by reading out one row, and high-speed focus detection processing while displaying a live view image. It can be performed.

  In addition, by performing pixel mixing that mixes data of a plurality of pixels, the SN ratio is improved, and the image quality and focus detection accuracy of an image displayed in live view can be improved.

  Alternatively, only when the focus detection operation is performed, the focus detection signal is read out from the focus detection pixel, and when the focus detection operation is not performed, only the image pixel is read out to the liquid crystal display unit 107 without reading the focus detection pixel. Since live view is displayed, high-quality live view images can be displayed.

  Further, by combining the focus detection process based on the pupil division method and the focus detection process based on the contrast method, when the focus detection process based on the pupil division method cannot be performed, it is possible to immediately switch to the focus detection process based on the contrast method.

  In each embodiment, the case where the AF control is continuously performed has been described. However, for example, when the AF lock is applied, the AF control may be terminated at the time of focusing once.

  Further, in each embodiment, as shown in FIG. 3, only the focus detection pixels that are paired in the horizontal direction, which is a feature of the present invention, are described, but in the vertical direction as shown in FIG. The focus detection pixels 501 and the focus detection pixels 504 may be arranged at pixel positions in rows and columns to be thinned out. In FIG. 9, in the focus detection pixel 501 on the upper side of the pupil division, the photoelectric conversion unit 502 is arranged in the upper half of the microlens 503 and the focus detection pixel 501. In the focus detection pixel 504 on the lower side of the pupil division, the photoelectric conversion unit 505 is arranged in the lower half of the microlens 506 and the focus detection pixel 504. The focus detection pixel 501 and the focus detection pixel 504 are paired to detect a pupil image divided in the vertical direction.

It is a block diagram which shows the structure of the electronic camera 101 which concerns on each embodiment. It is explanatory drawing which shows arrangement | positioning of the pixel of the solid-state image sensor 104 of 1st Embodiment. It is explanatory drawing for demonstrating the kind of pixel. It is explanatory drawing which shows arrangement | positioning of a color filter. It is explanatory drawing which shows arrangement | positioning of the pixel of the solid-state image sensor 104a of 2nd Embodiment. It is explanatory drawing which shows arrangement | positioning of the pixel of the solid-state image sensor 104b of 3rd Embodiment. It is a flowchart which shows the process of the electronic camera 101 which concerns on 3rd Embodiment. It is a flowchart which shows the process of the electronic camera 101 which concerns on 4th Embodiment. It is explanatory drawing which shows the pixel for a focus detection which performs pupil division in the vertical direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Electronic camera 102 ... Camera main body 103 ... Lens optical system 104 ... Solid-state image sensor 105 ... Signal processing part 106 ... Control part 107 ... Liquid crystal display part 108 ... Memory card 109 ... Lens drive unit 110 ... Operation panel 111 ... Memory 112 ... Image processing unit 113 ... Focus detection processing unit

Claims (9)

A lens optical system with a focus lens;
A solid-state imaging device incorporating a focus detection pixel by a pupil division phase difference method;
A display monitor;
When the pixel signal acquired by the solid-state image sensor is thinned out and displayed in real-time in live view, vertical line focus detection can be performed in the same row as the pixels on the solid-state image sensor corresponding to the pixels displayed on the display monitor. A control unit that thins out and reads out pixel signals from the solid-state imaging device so as to include focus detection pixels that are pupil-divided in a row direction, and displays them on the display monitor;
A phase difference focus control unit configured to detect a focus position using a pixel signal of the focus detection pixel read from the solid-state imaging device and control a position of the focus lens of the lens optical system. Electronic camera. The electronic camera according to claim 1,
When the controller reads out rows from the solid-state image sensor, the focus detection pixels are not included in the thinned rows. The electronic camera according to claim 1 or 2,
The phase difference focus control unit detects a focus position each time a pixel signal of the focus detection pixel is read out from the solid-state imaging device in units of rows, and controls the position of the focus lens of the lens optical system. A featured electronic camera. The electronic camera according to any one of claims 1 to 3,
The electronic camera, wherein the control unit includes a pixel signal of the focus detection pixel in a pixel displayed on the display monitor. A lens optical system with a focus lens;
A solid-state imaging device incorporating a focus detection pixel by a pupil division phase difference method;
A display monitor;
When pixel signals acquired by the solid-state image sensor are mixed in the row direction and live view display is performed in real time, vertical lines in the same row as the pixels on the solid-state image sensor corresponding to the pixels displayed on the display monitor Pixels read out from the solid-state imaging device include focus detection pixels that are pupil-divided in the row direction in which focus detection is possible, and the focus detection pixels that are mixed are in the same direction. A control unit that mixes signals and displays the signals on the display monitor;
A phase difference focus control unit configured to detect a focus position using a pixel signal of the focus detection pixel read from the solid-state imaging device and control a position of the focus lens of the lens optical system. Electronic camera. The electronic camera according to any one of claims 1 to 5,
2. The electronic camera according to claim 1, wherein the solid-state imaging device has an RGB color filter in a Bayer array, and the focus detection pixels are arranged in a G filter pixel. A lens optical system with a focus lens;
A solid-state imaging device incorporating a focus detection pixel by a pupil division phase difference method;
A display monitor;
A phase difference focus control unit that detects a focus position using a pixel signal of the focus detection pixel read from the solid-state image sensor and controls a position of the focus lens of the lens optical system;
When the phase difference focus control unit does not perform focus control when thinning out pixel signals acquired by the solid-state imaging device and performing live view display in real time, the solid-state imaging corresponding to the pixels displayed on the display monitor When the pixels on the element are read so as not to include the focus detection pixels and the phase difference focus control unit performs focus control, the same row as the pixels on the solid-state image sensor corresponding to the pixels displayed on the display monitor An electronic camera comprising: a control unit that reads out and displays on the display monitor so that focus detection pixels that are pupil-divided in a row direction in which vertical line focus detection is possible are included. A lens optical system with a focus lens;
A solid-state imaging device incorporating a focus detection pixel by a pupil division phase difference method;
A display monitor;
When the pixel signal acquired by the solid-state image sensor is thinned out and displayed in real-time in live view, vertical line focus detection can be performed in the same row as the pixels on the solid-state image sensor corresponding to the pixels displayed on the display monitor. A control unit that thins out and reads out pixel signals from the solid-state imaging device so as to include focus detection pixels that are pupil-divided in a row direction, and displays them on the display monitor;
A phase difference focus control unit that detects a focus position using a pixel signal of the focus detection pixel read from the solid-state image sensor and controls a position of the focus lens of the lens optical system;
Contrast focus for controlling the position of the focus lens of the lens optical system by accumulating the contrast information extracted from the pixel signal output from the solid-state image sensor and the focus lens position, detecting the focus position by a contrast method An electronic camera comprising: a control unit. The electronic camera according to claim 8,
The contrast focus detection unit detects a focus position by a contrast method using the information of the accumulated contrast information and the focus lens position when the phase difference focus detection unit does not finish the focus detection within a predetermined time, An electronic camera that controls a position of the focus lens of the lens optical system.

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