JP5207819B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus.

  In the manual focus (MS) mode of a silver halide camera, it is known to display a split image at the center of the viewfinder in order to make it easier for the operator to focus on the subject. When the split image divided vertically is out of focus, the pair of images in the split image is shifted to the left and right, and when the image is in focus, the left and right of the pair of images are eliminated. The operator focuses on the subject by operating the manual focus ring so that the image in the split image is not displaced.

  Patent Document 1 proposes a digital camera that displays a specific area such as the center of an electronic view image that is virtually shifted to the left and right like a split image from the amount of deviation between the subject distance and the focal length in the MF mode. . Japanese Patent Application Laid-Open No. 2004-228561 proposes a method in which a focus detection image pickup device is provided separately from a shooting image pickup device and a split image using a pupil divided image is combined and displayed on a shooting image.

Other publications include Patent Documents 3 to 6.
JP 2001-309210 A JP 59-50671 A JP 09-46715 A Japanese Patent Application Laid-Open No. 09-043507 Japanese Patent Laid-Open No. 05-093551 JP 2000-292686 A

  When a split image is displayed on an electronic view image during MF in a digital camera or digital video camera, it is mechanically difficult to change the presence / absence, size, position or division direction of the split image if it is a split image of a silver salt camera. It is.

  Further, the method of Patent Document 1 has a problem that a subject distance error in the split image is large and the direction of the camera changes. There is also a problem that when the subject that is a focus detection target changes, such as the subject moving, the amount of left / right shift of the split image suddenly changes, making it difficult for the operator to see. Further, there is a problem that the presence / absence of a split image, change in size, change in position, change in division direction, and the like cannot be appropriately performed on the subject image. The method of Patent Document 2 has a problem that it is not possible to adaptively change the size, position, and division direction of the split image on the subject image.

  Therefore, an object of the present invention is to provide an imaging device that displays a split image that facilitates manual focusing.

An imaging apparatus according to one aspect of the present invention includes a plurality of first objects that include a focus lens and each receive light passing through the entire exit pupil of a photographing lens that forms an image of a subject to generate the image of the subject. Enables manual focusing, an imaging device having pixels and a plurality of second pixels each receiving light passing through a partial region of the exit pupil of the photographing lens and generating a pupil-divided pixel signal And a split image display mode for displaying an image that is formed based on signals from the plurality of second pixels and a pupil generated from the plurality of second pixels is set. the two images on the basis of the divided-pixel signals generated as a split image, based on the respective contrast those said two images, change the display mode of the split image And having a split image region determination means that.

  ADVANTAGE OF THE INVENTION According to this invention, the imaging device which displays the split image which makes manual focus easy can be provided.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram of a digital camera (imaging device) 100 according to the present embodiment. FIG. 2 is a rear view of the digital camera (imaging device) 100 in a state where the operator holds the digital camera 100 sideways. FIG. 3 is a rear view of the digital camera (imaging device) 100 in a state where the operator holds the camera vertically.

  Reference numeral 1 denotes a photographic lens that forms an optical image of a subject by a light beam incident from the subject, and includes a single lens or a plurality of lenses including a focus lens 1a. The focus lens 1 a is driven and controlled in the optical axis direction by the lens control unit 4. A manual focus ring (manual focus operation member) 18 is rotatably provided on the outer periphery of the lens barrel of the photographic lens 1. The rotation of the manual focus ring 18 moves the focus lens 1a in the optical axis direction via a transmission mechanism (not shown).

Reference numeral 2 denotes an image sensor such as a CCD sensor or a CMOS sensor that converts an optical image into an electrical signal. The image sensor 2 is configured so that all pixels can be independently output. Some of the pixels are focus detection pixels (AF pixels), and phase difference detection focus detection (phase difference AF) is possible on the imaging surface. More specifically, the image sensor 2 receives a plurality of shooting pixels (first pixels) that each receive light passing through the entire exit pupil of the shooting lens 1 that forms the image of the subject to generate an image of the subject. ) . In addition, the imaging device 2 further includes a plurality of AF pixels (second pixels) that each receive light passing through a partial region of the exit pupil of the photographing lens 1. The plurality of AF pixels can receive light passing through the entire exit pupil of the photographing lens 1 as a whole. The plurality of AF pixels are pupil division pixels that generate pupil division pixel signals.

  Reference numeral 3 denotes an A / D converter that converts an analog signal output from the image sensor 2 into a digital signal. A lens control unit 4 controls the focus lens of the photographing lens 1 in accordance with the focus control unit 7. A development processing unit 5 receives an image signal from the output of the A / D conversion unit 3 and converts the RGB signal into a YUV signal.

  Reference numeral 6 denotes a pupil division pixel extraction unit that extracts the pupil division pixel signal generated by the AF pixel of the image sensor 2 from the output of the A / D conversion unit 3, and includes a left and right pupil division A pixel extraction unit 6a and a right and left pupil division B pixel. An extraction unit 6b, an upper and lower pupil division A pixel extraction unit 6c, and an upper and lower pupil division B pixel extraction unit 6d are provided. The extracted pupil division pixels are the left and right pupil division A image, the left and right pupil division B image, the upper and lower pupil division A image, and the upper and lower pupil division B image, respectively. In the present application, “A image” and “B image” may be simply referred to as “A image” and “B image”.

  Reference numeral 7 denotes a focus control unit that controls the lens control unit 4 based on the pupil division pixel signal obtained from the pupil division pixel extraction unit 6.

  Reference numeral 8 denotes a pupil division pixel signal to be used for a split image from the pupil division pixel signal extracted by the pupil division pixel extraction unit 6. The left and right pupil division A image, the left and right pupil division B image, the upper and lower pupil division A image, and the upper and lower pupil division B image This is a split image use pixel selection unit to select from. Reference numeral 9 denotes a split image use area extracting unit that extracts an area to be displayed as a split image. Reference numeral 10 denotes a scaling processing unit that scales the split image extracted by the split image use area extracting unit 9 into a display size. Reference numeral 11 denotes a scaling processing unit that performs scaling according to the display image size.

Reference numeral 12 denotes an evaluation value calculation unit (feature extraction unit or posture detection means ) that calculates evaluation values (features) of two images (A and B images described later) of the split image. Reference numeral 13 denotes a sensor (posture detection unit or posture detection means ) that can detect the posture of the camera (the posture shown in FIG. 2 and the posture shown in FIG. 3).

Reference numeral 14 denotes an operation unit (operation means) for inputting various operation instructions, and is configured by a single or a combination of a switch, a dial, a touch panel, pointing by eye-gaze detection, a voice recognition device, and the like. The operation unit 14 functions as a mode setting unit capable of setting a manual focus (MF) mode and a split image display mode. The MF mode enables MF. In the split image display mode, a split image formed by a plurality of AF pixels and divided into two images by a dividing line is displayed.

  As shown in FIGS. 2 and 3, the operation unit 14 includes a release button 14a, a mode dial 14b, operation buttons 14c to 14f, and a cross key 14g.

  The release button 14a performs a shooting operation. The mode dial 14b is a mode setting unit that sets a manual focus mode (MF mode) or an autofocus mode (AF mode). The operation buttons 14c to 14f are, in the MF mode, ON / OFF of the split image display mode, switching between vertical division and left / right division, ON / OFF of adaptive automatic change of the split image, switching of operation contents of the cross key 14g, menu display I do. In addition, the menu allows the operator to change the size, position, and division direction of the initially set split image. The cross key 14g changes the position and size of the split image.

Reference numeral 15 denotes a split image region determining unit (split image region determining unit) that determines a region to be displayed as a split image based on information from the evaluation value calculating unit 12, the posture detecting unit 13, and the operation unit 14. The split image area determination unit 15 has a memory (not shown). The memory stores the position and size of the split image and the direction of the dividing line (division direction) that are initialized for each posture of the digital camera 100. A timer 19 is connected to the split image area determination unit 15, and the split image area determination unit 15 can know that the set time has elapsed in the timer 19. An image display unit 17 is connected to the split image region determination unit 15, and the split image region determination unit 15 can know that the split image is displayed on the image display unit 17.

  Based on the detection result of the posture detection unit 13, the split image region determination unit 15 splits the split image use pixel selection unit 8, the split image use region extraction unit 9, and the image composition so as to generate the split image in the initially set division direction. The unit 16 is controlled. For example, when the posture detection unit 13 detects that the digital camera 100 is in the horizontal position as shown in FIG. 2, the split image 20 a divided vertically is displayed on the image display unit 17. When the posture detection unit 13 detects that the digital camera 100 is in the vertical position as shown in FIG. 3, the image display unit 17 displays the split image 20 b divided into left and right. The split image 20a has an A image 22a and a B image 24a, and the split image 20b has an A image 22b and a B image 24b. The upper and lower divided split images, the left and right divided split images, the A image, and the B image will be described in detail later.

  The pupil division pixel extraction unit 6, the split image use pixel selection unit 8, the split image use region extraction unit 9, the evaluation value calculation unit 12, and the split image region determination unit 15 function as a split image generation unit that generates a split image. .

  Reference numeral 16 denotes an image composition unit for composing the subject image and the split image. In accordance with the split image area determined by the split image area determining unit 15, selection by the split image use pixel selection unit 8, extraction by the split image use region extraction unit 9, and composition by the image composition unit 16 are performed.

  Reference numeral 17 denotes an image display unit comprising a TFT LCD or the like. The image display unit 17 is connected to the image synthesis unit 16 and displays the subject image and the split image in a synthesized state. The image data captured using the image display unit 17 is sequentially displayed to realize an electronic view function and an electronic viewfinder function.

  Next, the phase difference AF will be described with reference to FIGS.

  FIG. 4 is a plan view of the imaging pixels of the image sensor 2 and is a color array of the basic unit portion of the area sensor having 2 pixels × 2 pixels as a basic unit. 4 (a) is a (pure color) Bayer array, FIG. 4 (b) is a Bayer array applied to a color catching filter (complementary Bayer-like array), and FIG. 4 (c) is a complement of three colors plus G. (G-included complementary color array). Another commonly known pixel array is a complementary color checkered array of 2 × 4 pixel units, which is most often used as a sensor for a video movie camera. Further, a complementary color checkered color array (2 pixels × 8 pixels) proposed by the present applicant in Patent Document 3 is also applicable. The color arrangement of 2 pixels x 4 pixels and 2 pixels x 8 pixels is superior as an area sensor that handles moving images (video that performs interlaced scanning), but 2 pixels x 2 pixels are better for cameras that handle still images. Signal processing can be simplified and high-quality images can be obtained. In the following description, a pixel block of 2 pixels × 2 pixels will be described, but the present invention can also be applied to an area sensor having a color arrangement of 2 pixels × 4 pixels, 2 pixels × 8 pixels.

  FIG. 5 is a plan view of a pixel block including AF pixels of the image sensor 2. FIG. 5A shows a case of a pure color Bayer arrangement, and FIG. 5B shows a case of a complementary color Bayer-like arrangement or a G-included complementary arrangement. In FIG. 5, “S” is a focus detection pixel (AF pixel) for reading out photometric data. In this embodiment, an AF pixel is provided in the pixel of the image sensor 2 and a signal of the image sensor 2 is read to perform high-precision AF, and a mechanism unit required when a sensor is separately provided is eliminated. Is small and low-priced.

  Next, an AF pixel and a pixel block (area sensor) in which the pixel is arranged will be described. As an image sensor for a high pixel digital still camera, an interline CCD or a full frame CCD is mainly used. The interline CCD can read the imaged signal charge even when light is incident on the image sensor. However, in the full frame CCD, the signal charge must be closed unless the mechanical shutter provided on the front surface of the image sensor is closed. Cannot be read. As a solution to this, an improved full-frame CCD provided with a storage unit for accumulating charges for a line between the image area of a full-frame CCD and a horizontal CCD, and AF with a mechanical shutter opened thereby Partial reading is effective. In addition, a method of reading out only a partially necessary part in an image area for AF in an interline CCD at high speed (that is, a method of rapidly clearing signal charges other than the necessary part) is also effective. As a result, in both the interline CCD and the full frame CCD (however, an improved type), the signal charge in the area including the focus detection and photometry pixels arranged in the image area can be shortened without opening and closing the mechanical shutter many times. Can be read out in time. Hereinafter, an embodiment using an improved full frame CCD will be described, but the present invention can also be applied to an interline type.

  FIG. 6A is a plan view of a pixel (CCD cell) in the image area, and FIG. 6B is a cross-sectional view taken along AA in FIG. 6A and a potential profile. Reference numeral 201 denotes a clock gate electrode formed of light-transmitting polysilicon, and a semiconductor surface under the electrode is a clock phase region. The clock phase region is divided into two regions by ion implantation, one of which is a clock barrier region 202 and the other is a clock well region 203 formed by ion implantation so that the potential is higher than that of the clock barrier. It is. Reference numeral 204 denotes a virtual gate for fixing the channel potential by forming a P + layer on the semiconductor surface, and this region is a virtual phase region. This region is also divided into two regions by implanting N-type ions into a layer deeper than the P + layer, one of which is a virtual barrier region 205 and the other is a virtual well region 206. Reference numeral 207 denotes an insulating layer made of an oxide film or the like provided between the electrode and the semiconductor. Reference numeral 208 denotes a channel stop for separating the channels of each VCCD.

  Although not shown in the figure, a function of preventing a blooming phenomenon in which charges overflow into adjacent pixels and becomes a pseudo signal when strong light is incident is added. A typical method is to provide a horizontal overflow drain.

  That is, a drain made of an N + layer is provided in contact with each VCCD, and an overflow drain barrier is provided between the overflow drain and the charge transfer channel. Charges that exceed the height of the overflow drain barrier are swept away by the drain. The drain barrier height is fixed by dust in the ions, or an electrode (over drain barrier electrode) is formed on the overflow drain barrier, so that the drain barrier height can be controlled by controlling the voltage (VOD) applied to the drain electrode. It will be changed.

  In the transfer of the VCCD, an arbitrary pulse is applied to the clock electrode 202 to move the clock phase phase potential up and down with respect to the potential of the virtual layer, thereby transferring the charges in the direction of the horizontal CCD. In FIG. 6B, circles and arrows conceptually indicate charge movement. The above is the pixel structure of the image area, but the pixel structure of the storage unit is similar to this. However, in this region, since the upper part of the pixel is shielded from aluminum, it is not necessary to prevent blooming, so that the overflow drain is omitted. The H-CCD also has a virtual phase structure, but configures the layout of the clock phase region and the virtual phase region so that it can receive the charge from the VCCD and transfer it horizontally.

  FIG. 7A is a plan view of a structure in which a color filter layer 212 of either a pure color or a complementary color is arranged on the CCD cells (201 to 207) shown in FIG. b) is a BB cross-sectional view of FIG. Between the color filter layer 212 and the CCD cell, a protective layer 209 on the semiconductor surface and a metal light shielding film 210 for preventing color mixing of each color are provided. However, it may be composed of a black pigment layer made of the same material as the color filter. 211 is a smoothing layer for flattening the surface on which the color filter layer 212 is placed, and 213 is a protective layer for protecting the filter layer.

  FIG. 8 shows an array in which AF pixels are configured on a full frame CCD. A line having a plurality of AF pixels S1 and a line having AF pixels S2 are arranged on a normal Bayer array sensor. FIG. 9A is a plan view of the AF pixel S1, and FIG. 9B is a CC cross-sectional view of FIG. 9A. Reference numeral 210 denotes a photoelectric conversion element, and 214A denotes a metal light shielding film, which has an opening 214a that is biased (eccentric) from the center of the photoelectric conversion area of the pixel. Reference numeral 215 denotes a smooth layer for forming a plane for forming the microlens. Reference numeral 216 denotes a microlens. The AF pixel S1 does not have a filter layer and has a microlens 216 at the top. FIG. 10A is a plan view of the AF pixel S2, and FIG. 10B is a DD cross-sectional view of FIG. The AF pixel S2 includes a metal light-shielding film 214B having an opening 214b that is eccentric by the same distance in the opposite direction to the pixel center of the AF pixel S1. As shown in FIGS. 9A and 10B, the metal light shielding film 214A of the AF pixel S1 and the metal light shielding film 214B of the AF pixel S2 are provided so as to be bilaterally (or vertically) symmetrical. As a result, one of the images formed on the AF pixels by the light beams from the two positions of the exit pupil that is symmetric about the optical axis is photoelectrically converted by the row of the AF pixels S1, and the other is used for the AF. Photoelectric conversion is performed by the row of the pixels S2, and two images are obtained.

  For an area sensor exceeding 1 million pixels, the rows of AF pixels S1 and AF pixels S2 are almost the same in the arrangement of FIG. 8, and an approximate image is formed on the microlens 216. If the photographing lens 1 that connects the image to the image sensor 2 is in focus on the image sensor 2, the image signal from the S1 group in the row including the AF pixel S1 and the S2 group in the row including the AF pixel S2 are used. The image signals from these signal groups coincide. If the focusing point is in front of or behind the imaging surface of the image sensor 2, the image signal from the S1 group in the row including the AF pixel S1 and the signal in the S2 group in the row including the AF pixel S2 are used. A phase difference of the image signals from the group occurs. Then, the phase shift direction is reversed between the case where the image formation point is before and the case where the image formation point is after.

  In principle, this is the same as the pupil division phase difference AF of Patent Document 4. When the camera lens is viewed from the photoelectric conversion unit of the AF pixel S1 and when the camera lens is viewed from the photoelectric conversion unit of the AF pixel S2, it looks as if the pupil is divided into left and right with respect to the optical center. 11 and 12 show the relationship between the phase difference and the focus state. 11 and 12 show two AF pixels S1 and S2 that are adjacent to each other, the imaging pixels are omitted, and a plurality of AF pixels S1 and S2 are shown close to each other on the same cross section. In these drawings, a pair of AF pixels S1 and S2 is covered with the same microlens 216, but actually, the AF pixels S1 and S2 are covered with separate microlenses 216, respectively. .

  Light from a specific point of the subject passes through the pupil for the AF pixel S1 and enters the AF pixel S1, and the light beam L2 enters the AF pixel S2 through the pupil for the AF pixel S2. Divided. When the photographing lens 1 is in focus at a specific point, the two light beams L1 and L2 are condensed at one point on the surface of the microlens 216 and are applied to the AF pixels S1 and S2, as shown in FIG. Forms the same image. Thus, the A image signal read from the AF pixel S1 and the B image signal read from the AF pixel S2 are the same.

  On the other hand, when the photographing lens 1 is not in focus with respect to a specific point, the light beams L1 and L2 intersect at a position different from the surface of the microlens 216 as shown in FIG. The distance between the surface of the microlens 216 and the intersection of the two light beams L1 and L2, that is, the defocus amount is x. In addition, it is assumed that the image shift amount (phase difference) on the AF pixels S1 and S2 generated in this state corresponds to n pixels. Further, when the pixel pitch is d, the distance between the centers of gravity of the two pupils is Daf, and the distance from the principal point of the photographing lens 1 to the focal point is u, the defocus amount x is given by the following equation.

u is approximately equal to the focal length f of the taking lens 1 and is given by the following equation.

  FIG. 13 shows signal levels of the A image signal (image of the AF pixel S1) and the B image signal (image of the AF pixel S2) read from each of the AF pixels S1 and S2 on the image sensor 2. A shift amount (that is, an image shift amount) n × d occurs in these A image and B image signals. The focus control unit 7 obtains a shift amount (phase difference) n × d of the pair of image signals using a correlation calculation method, and obtains a defocus amount x using Formula 1 or 2 from the phase difference. The focusing control unit 7 calculates a target drive amount of the focus lens 1a for keeping the defocus amount x within a predetermined range (preferably zero) based on the calculated defocus amount. Then, the focus lens 1a is moved by the calculated target drive amount through the lens control unit 4. Thereby, a focused state by phase difference AF is obtained.

  14 to 16 are modified examples of the pixel arrangement shown in FIG. 8, and the arrangement of AF pixels S1 and S2 is different from the arrangement shown in FIG. In FIG. 8, the row of the AF pixel S1 and the row of the AF pixel S2 are slightly shifted, but there is no practical problem with the imaging device 2 exceeding 1 million pixels. 14 to 16 try to approximate the row of AF pixels S1 and the row of AF pixels S2 to the same place. In FIG. 14, AF pixels S1 and S2 are alternately arranged in the same row. FIG. 15 shows an AF pixel corresponding to the row of the AF pixel S2 by interpolating the first row and the second row by the AF pixel S1 by providing the row of the AF pixel S1 above and below the row of the AF pixel S2. The line data of S1 is created. FIG. 16 is a modified example of FIG. 14, in which the rows having alternating AF pixels S <b> 1 and S <b> 2 are arranged in two rows in a zigzag manner. As described above, the driving method for reading out only the AF pixel group and its portion enables high-speed and high-precision phase difference AF.

  In the image processing of the subject image in the image sensor 2, the AF pixels S1 and S2 are interpolated by the surrounding photographing pixels. As a result, an image pickup device is realized in which image quality is hardly deteriorated and the focus detection data other than the image capturing can be read. Assuming that such interpolation is performed, as shown in FIG. 5, if 2 × 2 pixels, three colors of photographic pixels and one AF pixel are used, interpolation is simple and image degradation does not become a problem. Of course, a 2 × 4 arrangement is also possible, but the distance between the AF pixel S1 row and the AF pixel S2 row is longer than 2 × 2 pixels. The above description can also be applied to an interline CCD image sensor, a frame transfer CCD image sensor, and an XY address image sensor.

  At the time of AF, a row including AF pixels S1 and S2 is read from the image sensor 2, and A / D converted by the A / D converter 3, and an image of the AF pixel S1 is obtained from each pixel value by the pupil division pixel extractor 6. And an image of the AF pixel S2. Then, the focus control unit 7 calculates the image shift amount by calculating the correlation between the two images, and controls the lens control unit 4 to move the focus lens in the photographing lens 1 according to the calculated shift amount. To do.

  At the time of shooting, the subject image is exposed on the image sensor 2, read out for all pixels, A / D converted by the A / D converter 3, and input to a signal processing circuit (not shown). In the signal processing circuit, first, the pixel values read from the AF pixels S1 and S2 are discarded, and instead, pixel values corresponding to the AF pixels S1 and S2 are generated from the surrounding pixels and interpolated. Thereafter, the luminance color difference signal is generated and compressed, and stored as an image file on a recording medium.

  In this embodiment, the AF pixels S1 and S2 are not used for photographing, and the AF pixels S1 and S2 are interpolated with surrounding photographing pixels. Interpolation processing may be performed after taking a video signal in a memory during still image shooting. However, when moving images are taken or when the electronic viewfinder is operated, about 30 images are repeatedly read out from the image pickup device per second, so that the lines on the image pickup device 2 are thinned out so that the processing is not in time. As described above, according to the present embodiment, the pixels read out in the thinning-out mode do not include AF pixels, and the number of pixels necessary and sufficient for generating a moving image can be read out.

  Further, as disclosed in Patent Documents 5 and 6, pupil division is performed orthogonally to the horizontal and vertical directions, thereby detecting the phase difference in both the horizontal direction and the vertical direction to improve focusing accuracy. it can. For example, FIG. 17A shows AF pixels for pupil division in the horizontal direction of the image sensor 2, and FIG. 17B shows AF pixels for pupil division in the vertical direction of the image sensor 2. Such AF pixels are uniformly arranged in the image sensor 2 at regular intervals. About 1% of the entire pixels of the image sensor 2 are allocated to the AF pixels. Here, the horizontal direction (left-right direction or horizontal direction) is orthogonal to the optical axis when the digital camera 100 is held so that the optical axis of the photographing lens 1 and the long side of the imaging region are parallel to the ground. And a direction along a straight line extending in the horizontal direction. The vertical direction (vertical direction or vertical direction) is orthogonal to the optical axis when the digital camera 100 is held so that the optical axis of the photographing lens 1 and the long side of the imaging region are parallel to the ground. A direction along a straight line extending in the vertical direction.

  The vertical stripe of the subject when the camera is photographed at the normal position detects the phase difference (defocus amount) by the AF pixel divided in the horizontal direction, and the horizontal stripe of the subject is detected by the AF pixel divided in the vertical direction. If AF is performed by detecting the phase difference (defocus amount), the focusing accuracy can be increased.

  In the present embodiment, left and right pupil division A pixels and B pixels are used as AF pixels obtained by dividing the image sensor 2 shown in FIG. 17A in the horizontal direction, and image data formed based on these is divided into left and right pupil division A. These are called an image and a B image. Further, in this embodiment, the pixels obtained by dividing the image sensor 2 shown in FIG. 17B in the vertical direction are divided into upper and lower divided A pixels and B pixels, and image data formed based on the divided upper and lower pupil divided A images. And B images.

  FIG. 18 is a diagram in which the vertically divided split image 20 c is displayed at the center of the image display unit 17. FIG. 19 is a diagram in which the left and right divided split image 20 d is displayed at the center of the image display unit 17. In this embodiment, the split image is rectangular, but it may be circular or elliptical depending on the design.

  20 to 22 are diagrams illustrating the vertically divided split image 20e. 21A shows the A image 22e of the vertically divided split image 20e, and the hatched area image of FIG. 21B shows the B image 24e of the vertically divided split image 20e. 22A shows the evaluation value calculation target area 23e of the A image 22e along the dividing line 21e of the vertically divided split image 20e, and FIG. 22B shows the area along the dividing line 21e of the vertically divided split image 20e. The evaluation value calculation target area 25e of the B image 24e is shown. The evaluation value calculation target regions 23e and 25e are adjacent portions where two images (A image 22e and B image 24e) are adjacent to each other, and are calculated targets for examining evaluation values along the dividing direction of the vertically divided split image 20e. Become. Hereinafter, an example of calculating the evaluation value will be described.

  For example, the evaluation value calculation target area 23e is composed of a vertical pixel integration value sequence of left and right pupil division A pixel evaluation values HAi (i = 0 to m), and the evaluation value calculation target area 25e is a left and right pupil division B pixel evaluation value HBi (i = 0 to m). The pixel evaluation values at this time are, for example, as shown in FIGS. 23A and 23B, and the evaluation values HAC and HBC are given by the following equations.

  Here, MAX [HAi (i = 0 to m)] is the maximum value of the left and right pupil division A pixel evaluation value HAi (i = 0 to m), and MIN [HAi (i = 0 to m)] is the left and right pupil division A. The minimum value of the pixel evaluation value HAi (i = 0 to m) is shown. When HAC and HBC are above a certain value, it is determined that the contrast is high, and when HAC and HBC are below a certain value, it can be determined that the contrast is low. Further, in the focusing assistance by the operator in the MF, if both HAC and HBC are above a certain value, it is determined that the contrast is sufficient, and if at least one of HAC and HBC is less than a certain value, the contrast is It can be judged that it is insufficient.

  24 to 26 are diagrams illustrating the left and right divided split image 20f. The hatched area image in FIG. 25A shows the A image 22f of the left and right divided split image 20f, and the hatched area image in FIG. 25B shows the B image 24f of the left and right divided split image 20f. FIG. 26A shows the evaluation value calculation target region 23f of the A image 22f along the dividing line 21f of the left and right divided split image 20f, and FIG. 26B shows the dividing line 21f of the left and right divided split image 20f. The evaluation value calculation target area 25f of the B image 24f is shown. The evaluation value calculation target areas 23f and 25f are calculation targets for examining the evaluation value along the dividing direction of the left and right split image 20f. Hereinafter, an evaluation value calculation example will be described.

  For example, the evaluation value calculation target area 23f is composed of a horizontal pixel integrated value sequence of upper and lower pupil division A pixel evaluation values VAi (i = 0 to n), and the evaluation value calculation target area 25f is an upper and lower pupil division B pixel evaluation value VBi (i = 0 to n). The pixel evaluation values at this time are, for example, as shown in FIGS. 27A and 27B, and the evaluation values VAC and VBC are given by the following equations.

  Here, MAX [VAi (i = 0 to n)] indicates the maximum value among the upper and lower pupil division A pixel evaluation values VAi (i = 0 to n), and MIN [VAi (i = 0 to n). ] Indicates the minimum value among the upper and lower pupil division A pixel evaluation values VAi (i = 0 to n). When VAC and VBC are above a certain value, it is determined that the contrast is high, and when VAC and VBC are below a certain value, it can be determined that the contrast is low. Further, in the focusing assistance by the operator in the MF, it is determined that the contrast is sufficient when both VAC and VBC are above a certain value, and when at least one of VAC and VBC is less than a certain value, the contrast is It can be judged that it is insufficient.

  Although feature extraction is performed based on the evaluation value calculation result here, feature extraction is performed by examining the frequency distribution to obtain the correlation calculation evaluation value, or examining whether periodic features can be seen. May be.

  FIG. 28 is a diagram illustrating an example in which the contrast in the vertically divided split image 20g is insufficient. In FIG. 28, the wall of the house that is the subject is an area of the vertically divided split image 20g. As shown in FIGS. 29A and 29B, the contrast between the left and right pupil division A image 22g and the left and right pupil division B image 24g of the upper and lower division split image 20g is not high. In this case, the operator does not have enough MF using the split image.

  Hereinafter, with reference to FIG. 30, it is a flowchart for demonstrating the operation | movement in the split image display mode of a present Example. In FIG. 30, “S” represents a step.

  The split image area determination unit 15 determines whether or not the MF mode is set by the mode dial 14b of the operation unit 14 (S1), and ends the process if the MF mode is not set. When the split image area determination unit 15 determines that the MF mode is set (S1), the split image region determination unit 15 determines whether the split image display mode is set by the operation button (14c-14f) of the operation unit 14 (S2). . When the split image area determination unit 15 determines that the split image display mode is not set by the operation unit 14 (S2), the process ends.

  Next, when the split image area determination unit 15 determines that the split image display mode is set (S2), the split image use pixel selection unit 8 selects one to be used for the split image from the pupil division pixel signal. Then, the split image usage area extraction unit 9 extracts an area to be displayed as a split image, and the scaling processing unit 10 scales the split image extracted by the split image usage area extraction unit 9 to a display size. Next, the image combining unit 16 combines the subject image and the split image, and the image display unit 17 displays the combined image (S3). In this case, a split image having a split image division direction, position, and size that is given as an initial value is generated and displayed along with the subject image on the electronic view.

  Next, the split image area determination unit 15 refers to the operation unit 14 and determines whether there is any operation by the operator (S4). When the split image area determination unit 15 determines that there is an operation (S4), it determines whether or not the MF mode is set by the operation unit 14 (S10). If it is not set, the process ends. Next, when the split image area determination unit 15 determines that the MF mode is set, the split image region determination unit 15 determines whether the split image display mode is set by the operation unit 14 (S11). To do.

  Next, when the split image area determination unit 15 determines that the split image display mode is set by the operation unit 14 (S11), the split image area determination unit 15 determines whether an instruction to change the split image area is given (S12). The change instruction in this case is an instruction to change the region such as the position, width, and division direction of the split image by the operation of the operation unit 14 by the operator.

  On the other hand, when the split image area determination unit 15 determines that there is no operation (S4) or when it is determined that the change of the split image area is not instructed (S12), the set time has elapsed with reference to the timer 19 Whether or not (S5). If the split image area determination unit 15 determines that the set time has not elapsed (S5), the process returns to S4. On the other hand, when the split image area determination unit 15 determines that a certain time has elapsed without any operation (S5), it takes in the evaluation value (contrast) calculated by the evaluation value calculation unit 12 (S6).

  In this embodiment, as shown in FIG. 1, the image display unit 17 and the timer 19 are connected to the split image region determining unit 15, and the split image region determining unit 15 makes a determination in S5, and the evaluation value in S6 is determined. The capture timing is controlled. However, in another embodiment, the image display unit 17 and the timer 19 are connected to the split image use pixel selection unit 8 so that the split image use pixel selection unit 8 makes a determination in S5 and calculates the evaluation value instead of S6. May be controlled. Needless to say, another control unit (not shown) may perform evaluation value fetch timing and calculation timing.

  Next, the split image region determination unit 15 determines whether or not the correlation between the characteristics of the two images (A image and B image) of the split image is sufficient (S7). In the present embodiment, “the feature correlation is sufficient” means that the contrast of each feature is sufficient and the feature of the out-of-focus characteristic is sufficiently expressed. On the other hand, “feature correlation is sufficient” means that MF cannot be performed (including a case where it is difficult) with each feature of the two images (A image and B image) of the split image.

  When the split image area determination unit 15 determines that the feature correlation is sufficient (S7), the process returns to S4. On the other hand, when it is determined that the feature correlation is not sufficient (S7) or when it is determined that the split image area has been changed (S12), the split image area determination unit 15 changes the split image area (S8). The change in S8 includes any one of change of the position of the split image, change of the direction of the dividing line (division direction), and enlargement of the split image. Then, the split image use pixel selection unit 8, the split image use region extraction unit 9, and the image composition unit 16 are controlled to update the split image display by the image display unit 17 (S9). Thereafter, the process returns to S4.

  Hereinafter, with reference to FIG. 31 and FIG. 32, the enlargement on the display of the split image (that is, the enlargement of the A image and the B image) in the change of S8 of FIG. FIG. 31 shows the upper and lower sides expanded in the horizontal direction when the contrast is insufficient (that is, as shown in FIG. 28, the contrast between the left and right pupil division A images 22g and B image 24g of the split image 20g is not sufficient). It is a figure which shows the division | segmentation split image 20h. FIG. 32A is a graph showing the evaluation value of the left and right pupil division A image 22h of the upper and lower division split image 20h. FIG. 32B is a graph showing the evaluation value of the left and right pupil division B image 24h of the upper and lower division split image 20h. The split image area determination unit 15 examines the contrast between the A image and the B image of the split image 20g, and automatically displays the split image up to an area where sufficient contrast is obtained, as shown in FIGS. 32 (a) and 32 (b). Spread left and right. Similarly, in the case of a split image on the left and right, the image is automatically expanded up and down to an area where sufficient contrast can be obtained. Note that the direction in which the split image is enlarged is the direction in which the dividing line extends. The term “enlargement” as used herein refers to enlargement on the display, and it does not matter whether the signal amount in the enlargement area is increased or not when performing signal processing.

  Next, with reference to FIGS. 33 and 34, the change of the position of the split image (that is, the change of the positions of the A image and the B image) in the change of S8 of FIG. 30 will be described. FIG. 33 is a diagram in which the position of the split image 20g is changed to the position of the split image 20i when the contrast is insufficient as shown in FIG. FIG. 34A is a graph showing the evaluation value of the left and right pupil division A image 22i of the upper and lower division split image 20i. FIG. 34B is a graph showing the evaluation value of the left and right pupil division B image 24i of the upper and lower division split image 20i. The split image area determination unit 15 checks the contrast of the A image and the B image of the split image 20g, and as shown in FIGS. 34 (a) and 34 (b), the position of the split image 20g is at a position where sufficient contrast is obtained. Automatically change. Similarly, in the case of a left / right split image, the position is automatically changed to an area where sufficient contrast can be obtained.

  Next, with reference to FIGS. 35 to 42, the change of the split image dividing direction (direction of the dividing line) among the changes of S8 of FIG. 30 will be described. FIG. 35 is a diagram illustrating a case where the focus shift feature is not sufficient in the vertically divided split image 20j. FIG. 36A is a graph showing the evaluation value of the left and right pupil division A image 22j of the upper and lower division split image 20j. FIG. 36B is a graph showing the evaluation value of the left and right pupil division B image 24j of the upper and lower division split image 20j. It will be understood that the evaluation values of the A image 22j shown in FIG. 36A and the B image 24j shown in FIG. 36B are almost the same. The vertically divided split image 20j shown in FIG. 35 is not a case where the contrast of the A image 22g and the B image 24g is low as shown in FIG. However, from the viewpoint of the operator, there is almost no deviation between the A image 22j and the B image 24j of the vertically divided split image 20j, making it difficult to focus.

  Therefore, the division direction is changed as shown in FIG. FIG. 37 is a diagram showing a left / right divided split image 20k in the same image portion as FIG. FIG. 38A is a graph showing the evaluation value of the A image 22k of the left and right divided split image 20k. FIG. 38B is a graph showing the evaluation value of the B image 24k of the left and right divided split image 20k. As shown in FIGS. 38 (a) and 38 (b), the evaluation values of the A image 22k and the B image 24k are clearly different. In the case of the left and right split split image 20k shown in FIG. This makes it easier for the operator to perform the focusing operation. In this case, the split image region determination unit 15 calculates the evaluation values of the division directions (upper and lower divisions and left and right divisions) of different split images, and selects and displays a division direction with sufficient features. When the feature extraction is not sufficient in the vertically divided split image 20j shown in FIG. 35, the split image area determining unit 15 automatically switches to the left and right divided split image 20k as shown in FIG. As a result, it is possible to automatically select and display a split image that is easy for the operator to perform sufficient focusing work.

  As described above, S8 shown in FIG. 30 determines that MF cannot be performed with the features of the two images (A image and B image) extracted by the split image use pixel selection unit 8 which is the feature extraction unit. Done in case. Then, in S8, the split image area determination unit 15 performs any one of change of the position of the split image, change of the direction of the dividing line (division direction), and enlargement of the split image. As a result, a split image suitable for MF can be provided to the operator together with the subject image.

  In this embodiment, the split image using the upper and lower pupil divided images and the left and right pupil divided images has been described. However, the present invention is similarly applied to the oblique split image using the pupil divided images divided in the oblique direction. Is possible.

It is a block diagram of the digital camera (imaging device) of the present embodiment. FIG. 2 is a rear view of the digital camera shown in FIG. 1 in a state of being held sideways. FIG. 2 is a rear view of the digital camera shown in FIG. 1 in a state where it is held vertically. It is a top view of the pixel block of the pixel for imaging | photography of the image pick-up element shown in FIG. FIG. 2 is a plan view of a pixel block including AF pixels of the image sensor shown in FIG. 1. It is a figure which shows the structure of the pixel for imaging | photography of the image pick-up element shown in FIG. It is a figure which shows the structure of the pixel for imaging | photography of the image pick-up element shown in FIG. It is a figure which shows the pixel arrangement | sequence of the image pick-up element shown in FIG. It is sectional drawing which shows the structure of the pixel for AF of the image pick-up element shown in FIG. It is sectional drawing which shows the structure of the pixel for AF of the image pick-up element shown in FIG. FIG. 11 is an optical path diagram for explaining the operation of the AF pixel shown in FIG. 9 or FIG. 10. FIG. 11 is an optical path diagram for explaining the operation of the AF pixel shown in FIG. 9 or FIG. 10. It is a graph which shows the signal read from two AF pixels of the image pick-up element 2 shown in FIG. It is a figure which shows the modification of the pixel arrangement | sequence of the image pick-up element shown in FIG. It is a figure which shows another modification of the pixel arrangement | sequence of the image pick-up element shown in FIG. It is a figure which shows another modification of the pixel arrangement | sequence of the image pick-up element shown in FIG. It is a figure which shows the pixel for AF which divides | segments the image pick-up element shown in FIG. 1 into the horizontal and vertical direction. It is the figure which displayed the upper and lower division | segmentation split image on the center part of the display part shown in FIG. It is the figure which displayed the right-and-left division | segmentation split image in the center part of the display part shown in FIG. It is a figure which shows an up-and-down division | segmentation split image. It is a figure which shows A image and B image of the up-and-down division | segmentation split image shown in FIG. It is a figure which shows the evaluation value calculation object area | region of A image and B image shown in FIG. It is a graph of the evaluation value calculation object area | region of A image and the evaluation value calculation object area | region of B image shown in FIG. It is a figure which shows a right-and-left division | segmentation split image. It is a figure which shows A image and B image of the right-and-left division | segmentation split image shown in FIG. It is a figure which shows the evaluation value calculation object area | region of A image and B image shown in FIG. It is a graph of the evaluation value of the evaluation value calculation target area of the A image and the evaluation value calculation target area of the B image shown in FIG. It is a figure which shows the up-and-down division | segmentation split image in case the contrast of A image and B image is inadequate. It is a graph of the evaluation value of A image and B image of the up-and-down division | segmentation split image shown in FIG. It is a flowchart for demonstrating the operation | movement in the split image display mode of a present Example. It is a figure explaining an example of S8 of FIG. It is a graph for demonstrating an example of S8 of FIG. It is a figure explaining another example of S8 of FIG. It is a graph for demonstrating another example of S8 of FIG. It is a figure explaining another example of S8 of FIG. It is a graph for demonstrating another example of S8 of FIG. It is a figure which solves the problem of FIG. It is a graph of the evaluation value of A image and B image of the split image shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shooting lens 1a Focus lens 6 Pupil division pixel extraction part 8 Split image use pixel selection part 9 Split image use area extraction part 12 Evaluation value calculation part 13 Posture detection part 14 Operation part 15 Split image area determination part 17 Display part 19 Timer 20a ˜20k Split image 22a˜22k A image 23e A portion adjacent to B image of A image (evaluation value calculation target region)
24a-24k B image 25e Adjacent part of B image with A image (evaluation value calculation target region)
100 Digital camera (imaging device)

Claims (7)

A plurality of first pixels each including light that passes through the entire exit pupil of the photographing lens that includes a focus lens and forms an image of the subject and generates the image of the subject, and each of the exits of the photographing lens A plurality of second pixels that receive light passing through a partial region of the pupil and generate a pupil-divided pixel signal; and
When both a manual focus mode that enables manual focus and a split image display mode that displays an image formed based on signals from the plurality of second pixels are set, the plurality of second pixels based on the pupil division pixel signals generated from the generated two images as the split image, based on the respective contrast those the two images, the split image region determining means for changing a display mode of the split image An imaging apparatus comprising: The imaging apparatus according to claim 1, wherein the contrast is an integral value in a direction perpendicular to a dividing line between the two images. 3. The imaging apparatus according to claim 1, wherein the split image area determination unit enlarges the split image based on respective contrasts of the two images . 4. The split image area determination unit according to claim 3 , wherein when the split image is enlarged, each image is enlarged in a direction in which a dividing line extends when the split image is enlarged based on the contrast of each of the two images . Imaging device. The split image region determination means, before when the set time in the timer after displaying kiss split image has elapsed, according to claim 1, wherein the incorporation of each of the contrast of the previous SL two images The imaging device as described in any one of them. The imaging apparatus further includes an attitude detection unit that detects an attitude of the imaging apparatus,
The said split image area | region determination means determines the area | region displayed as the said split image based on the detection result of the said attitude | position detection means, and the stored information, The Claim 1 characterized by the above-mentioned. The imaging device described. The imaging apparatus further includes an operation unit operated to change at least one of a position, a size, and a dividing line direction of the split image,
The split image area determining means changes the area of the split image based on the information changed by the operating means when the operating means is operated. The imaging device according to item.