Focusing control device, method of operating the focusing control device, operating program of the focusing control device, and imaging device

Abstract

The present invention provides a focus control device capable of suppressing a decrease in the accuracy of detecting the distance to a subject based on the output from a phase difference detection pixel, an operating method for the focus control device, an operating program for the focus control device, and an imaging device. [Solution] The focusing calculation unit obtains the defocus amount by calculating it according to the first added calculation signal and the second added calculation signal, which are the sum of the calculation signals of calculation data, which are the pixel values ​​of a plurality of phase difference detection pixels. The focusing lens drive control unit performs focusing control using the adapted defocus amount, which is the defocus amount that satisfies the adoption conditions.

Description

Technical Field

[0001] The technology of the present disclosure relates to a focus control device, an operating method of the focus control device, an operating program of the focus control device, and an imaging device.

[0002] Patent Document 1 describes an imaging device having an image sensor, a calculating means, a detecting means, and a focus adjusting means. The image sensor outputs a pair of image signals based on a pair of light beams that have passed through different exit pupil regions of a photographic optical system including a focus lens. The calculating means calculates a plurality of focus adjustment evaluation values with different setting conditions based on the pair of image signals in a focus adjustment region within the image captured by the image sensor. The detecting means detects a plurality of saturations for each of the plurality of focus adjustment evaluation values. The focus adjusting means drives the focus lens using the focus adjustment evaluation value for focus adjustment selected based on the plurality of saturations among the plurality of focus adjustment evaluation values. The setting conditions are at least one of a visual field range for calculating the focus adjustment evaluation value, a filter applied to the pair of image signals, and the number of pixels for horizontal pixel addition performed on the pair of image signals. The detecting means changes parameters used when detecting the plurality of saturations based on the setting conditions.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] One embodiment of the technology according to the present disclosure provides a focus control device, an operating method of the focus control device, an operating program of the focus control device, and an imaging device capable of suppressing a decrease in detection accuracy of the distance to a subject based on the output from pixels for phase difference detection.

Means for Solving the Problems

[0005] The focusing control device of this disclosure includes a processor, which acquires a focusing evaluation value corresponding to the sum of the pixel values ​​of a plurality of phase difference detection pixels, and performs focusing control using the focusing evaluation value that satisfies preset conditions.

[0006] Preferably, the processor detects the distance to the subject based on a focus evaluation value that satisfies certain conditions, and performs focus control according to the distance.

[0007] The preferred condition is that the focus evaluation value, which relates to the difference between the current position of the focus lens and the focused position of the focus lens, is within a first threshold range.

[0008] The processor preferably sets the speed of the focusing lens to a speed that can secure a preset number of focus evaluation values.

[0009] The processor preferably switches between a pixel addition mode, which adds pixel values, and a non-pixel addition mode, which does not add pixel values.

[0010] Preferably, the focus evaluation value that satisfies the conditions is the focus evaluation value obtained after the first threshold count following the switch from non-pixel addition mode to pixel addition mode.

[0011] It is preferable that the processor does not use the focus evaluation value acquired between the time set for switching from non-pixel addition mode to pixel addition mode as the focus evaluation value that satisfies the conditions.

[0012] The processor determines the contrast value in a set area of ​​the imaging surface of the image sensor on which the phase-difference detection pixels are arranged, and it is preferable that the focus evaluation value that satisfies the conditions is the focus evaluation value calculated when the contrast value is within the second threshold range.

[0013] The processor determines the intensity of frequency components in a set region of the imaging surface of the image sensor on which the phase difference detection pixels are arranged, and it is preferable that the focus evaluation value that satisfies the conditions is the focus evaluation value calculated when the intensity at the reference frequency is within the third threshold range.

[0014] It is preferable that the processor does not perform focus control using a focus evaluation value if there is no focus evaluation value that satisfies the conditions.

[0015] The processor preferably adds the pixel values ​​of multiple phase difference detection pixels that are aligned in the phase difference detection direction.

[0016] The method of operating the focusing control device of this disclosure includes obtaining a focusing evaluation value corresponding to the sum of the pixel values ​​of a plurality of phase difference detection pixels, and performing focusing control using the focusing evaluation value that satisfies preset conditions.

[0017] The operating program for the focusing control device of this disclosure causes a computer to perform a process that includes acquiring a focusing evaluation value corresponding to the sum of the pixel values ​​of a plurality of phase difference detection pixels, and performing focusing control using the focusing evaluation value that satisfies a preset condition.

[0018] The imaging apparatus of this disclosure includes the focusing control device described above. [Brief explanation of the drawing]

[0019] [Figure 1] This is a diagram showing the configuration of the imaging device. [Figure 2] This diagram shows the arrangement of pixels in an image sensor. [Figure 3] This figure shows the typical pixel configuration. [Figure 4] This figure shows the configuration of the first phase difference detection pixel. [Figure 5] This figure shows the configuration of the second phase difference detection pixel. [Figure 6] This graph shows the phase difference between the first and second calculation signals. [Figure 7] This is a diagram showing the focus adjustment area. [Figure 8] This diagram shows the data used for calculations, with (A) representing the first calculation data and (B) representing the second calculation data. [Figure 9]It is a block diagram showing the detailed configuration of the control unit. [Figure 10] It is a block diagram showing the processing unit of the CPU. [Figure 11] It is a block diagram showing the detailed configuration of the focus calculation unit. [Figure 12] It is a diagram showing the processing of the pixel addition unit, where (A) shows the processing for the first calculation data and (B) shows the processing for the second calculation data respectively. [Figure 13] It is a diagram showing the processing of the correlation calculation unit. [Figure 14] It is a diagram showing a scene where the subject distance varies greatly. (A) shows the case where a distant mountain is the subject, and (B) shows the case where the subject is switched from a distant mountain to a nearby person. [Figure 15] It is a diagram showing the correlation curve when the subject distance varies greatly, and indicating that the detection of the phase difference and the calculation of the defocus amount become impossible. [Figure 16] It is a diagram for explaining the reason for performing pixel addition when the subject distance varies greatly. [Figure 17] It is a diagram showing the processing of the mode switching setting unit and the mode switching unit. [Figure 18] It is a diagram showing the adoption conditions. [Figure 19] It is a diagram showing the adoption determination result when the defocus amount satisfies the adoption conditions in the pixel addition mode. [Figure 20] It is a diagram showing the adoption determination result when the defocus amount does not satisfy the adoption conditions in the pixel addition mode. [Figure 21] It is a diagram showing the processing of the distance detection unit, where (A) shows the case where there are the required number of matching defocus amounts, and (B) shows the case where there are no required number of matching defocus amounts. [Figure 22] It is a diagram showing the transition of the current position of the focus lens and the estimated in-focus position when switching from a distant view to a close view. [Figure 23] It is a diagram showing the transition of the current position of the focus lens and the estimated in-focus position when switching from a distant view to a close view. [Figure 24] This figure shows the change in the current position of the focus lens and the estimated focus position when switching from a distant view to a close-up view, while the subject is moving. [Figure 25] This is a flowchart showing the processing procedure of the control unit. [Figure 26] This diagram shows the case where the number of suitable defocus amounts is insufficient. [Figure 27] This figure shows a second embodiment in which the speed of the focus lens is set to a slower speed if the number of suitable defocus amounts is insufficient. [Figure 28] This figure shows another example of hiring requirements. [Figure 29] This figure shows the current position of the focus lens and the change in the estimated focus position when switching from a distant view to a close-up view. [Figure 30] This figure shows a fourth embodiment in which the appropriate defocus amount is determined based on the contrast value. [Figure 31] This figure shows a fifth embodiment in which the appropriate defocus amount is determined based on the intensity of frequency components. [Figure 32] This graph shows the processing of the adoption / rejection determination unit of the fifth embodiment. [Figure 33] This figure shows another example of the second switching condition. [Modes for carrying out the invention]

[0020] [First Embodiment] As an example, as shown in Figure 1, the imaging device 10 is, for example, a mirrorless interchangeable-lens digital camera and includes an imaging optical system 11 and an image sensor 12. The imaging optical system 11 has multiple types of lenses for imaging subject light onto the image sensor 12. Specifically, the imaging optical system 11 has an objective lens 13, a focusing lens 14, and a zoom lens 15. These lenses 13 to 15 are arranged in this order from the object side (subject side) to the imaging side (image sensor 12 side). Although simplified in Figure 1, each lens 13 to 15 is actually a lens group made up of multiple lenses. The imaging optical system 11 also has an aperture 16. The aperture 16 is located on the imaging side of the imaging optical system 11. The imaging device 10 may be a type in which the lens barrel containing the imaging optical system 11 etc. and the main body containing the image sensor 12 etc. are integrated, or it may be a so-called interchangeable lens type in which the lens barrel and the main body are separate.

[0021] The focus lens 14 is provided with a focus lens drive mechanism 17, the zoom lens 15 is provided with a zoom lens drive mechanism 18, and the aperture 16 is provided with an aperture drive mechanism 19. The focus lens drive mechanism 17 includes a focus cam ring that holds the focus lens 14 and has a cam groove formed on its outer circumference, a focus motor that rotates the focus cam ring around the optical axis OA to move the focus cam ring along the optical axis OA, and a driver for the focus motor. Similarly, the zoom lens drive mechanism 18 includes a zoom cam ring that holds the zoom lens 15 and has a cam groove formed on its outer circumference, a zoom motor that rotates the zoom cam ring around the optical axis OA to move the zoom cam ring along the optical axis OA, and a driver for the zoom motor. The aperture drive mechanism 19 includes an aperture motor that opens and closes multiple aperture blades of the aperture 16, and a driver for the aperture motor.

[0022] The focusing motor, zooming motor, and aperture motor are, for example, stepping motors. In this case, the position of the focusing lens 14 and the zoom lens 15 on the optical axis OA, as well as the opening degree of the aperture 16, can be derived from the drive amounts of the focusing motor, zooming motor, and aperture motor. Alternatively, instead of using the drive amounts of the focusing motor and zooming motor, position sensors may be provided to detect the positions of the focusing lens 14 and the zoom lens 15.

[0023] The motors or drivers and other electrical components of each drive mechanism 17-19 are connected to the control unit 20. The electrical components of each drive mechanism 17-19 are driven under the control of the control unit 20. More specifically, the control unit 20 drives the electrical components of each drive mechanism 17-19 by issuing drive signals in response to user instructions input via the operation unit 21. For example, if an instruction to change the angle of view to the telephoto side is input via the angle of view change switch on the operation unit 21, the control unit 20 issues a drive signal to the driver of the zoom motor of the zoom lens drive mechanism 18, causing the zoom lens 15 to move to the telephoto side.

[0024] The focus motor, zoom motor, and aperture motor output drive values ​​to the control unit 20. The control unit 20 derives the position of the focus lens 14 and the zoom lens 15 on the optical axis OA, as well as the opening degree of the aperture 16, from the drive values.

[0025] The image sensor 12 is, for example, a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor and has an imaging surface 42 (see Figure 2) that captures subject light. The image sensor 12 is arranged so that the center of the imaging surface 42 coincides with the optical axis OA, and the imaging surface 42 is perpendicular to the optical axis OA. Here, "coincidence" and "perpendicularity" refer not only to perfect coincidence and orthogonality, but also to coincidence and orthogonality that include errors that are generally acceptable in the art to which the technology of this disclosure belongs.

[0026] An image sensor driver 22 is connected to the image sensor 12. The image sensor driver 22 is connected to the control unit 20. Under the control of the control unit 20, the image sensor driver 22 controls the timing of subject light imaging by the image sensor 12 by supplying vertical scanning signals and horizontal scanning signals to the image sensor 12.

[0027] A shutter 23 is provided between the imaging optical system 11 and the image sensor 12. The shutter 23 is, for example, a focal-plane shutter having a front curtain and a rear curtain. A shutter drive mechanism 24 is connected to the shutter 23. The shutter drive mechanism 24 includes an electromagnet that holds the front curtain and the rear curtain and releases its hold to allow the front curtain and the rear curtain to move, and its driver, etc. The shutter drive mechanism 24 is driven under the control of the control unit 20 to open and close the shutter 23.

[0028] The control unit 20 is connected to various components such as the image input controller 25, image memory 26, and image processing unit 27 via a bus line 28. Other components connected to the bus line 28 include VRAM (Video Random Access Memory) 29, display control unit 30, media controller 31, and instruction receiving unit 32. Although not shown in the diagram, the bus line 28 is also connected to a strobe drive control unit that controls the operation of the strobe device, an external communication interface (I / F) that communicates with external devices via connection terminals such as a USB (Universal Serial Bus) terminal, and a wireless communication interface (I / F).

[0029] The image input controller 25 receives image data obtained by capturing the subject light from the image sensor 12. The image input controller 25 outputs the image data to the image memory 26. The image memory 26 is, for example, SDRAM (Synchronous Dynamic Random Access Memory) and temporarily stores the image data.

[0030] The image processing unit 27 reads unprocessed image data from the image memory 26. The image processing unit 27 performs various image processing operations on the image data. These operations include, for example, offset correction, sensitivity correction, pixel interpolation, white balance correction, gamma correction, demosaicing, luminance signal and chrominance signal generation, edge enhancement, and color correction. The image processing unit 27 then writes the processed image data back to the image memory 26.

[0031] Image data that has undergone various image processing steps and is intended to be displayed as a live view image (also called a through image) is input to VRAM29 from image memory26. VRAM29 has an area for storing image data for two consecutive frames. The image data stored in VRAM29 is sequentially overwritten with new image data. VRAM29 sequentially outputs the newer image data from the two consecutive frames of image data to the display control unit30.

[0032] The display control unit 30 performs the function of a so-called video encoder, converting image data from the VRAM 29 into video data and outputting it to either the viewfinder monitor 33 or the rear monitor 34. This allows the user to view the live view image through either the viewfinder monitor 33 or the rear monitor 34. The display frame rate of the live view image is, for example, 60 fps (frames per second).

[0033] The decision of whether to output the video data to the viewfinder monitor 33 or the rear monitor 34 is made, for example, as follows: An eye detection sensor is provided in the viewfinder. If the eye detection sensor detects that the user is looking through the viewfinder, the video data is output to the viewfinder monitor 33. Conversely, if the eye detection sensor detects that the user is not looking through the viewfinder, the video data is output to the rear monitor 34.

[0034] When the shutter release button on the control unit 21 is fully pressed to initiate still image or video recording, the image processing unit 27 compresses the image data in the image memory 26. For still images, the image processing unit 27 compresses the image data using, for example, the JPEG (Joint Photographic Experts Group) format. For videos, the image processing unit 27 compresses the image data using, for example, the MPEG (Moving Picture Experts Group) format. The image processing unit 27 then outputs the compressed image data to the media controller 31.

[0035] The media controller 31 records the compressed image data from the image processing unit 27 onto the memory card 35. The memory card 35 is detachably mounted in a memory card slot (not shown).

[0036] When the image playback mode is selected via the mode switch on the operation unit 21, the media controller 31 reads image data from the memory card 35 and outputs it to the image processing unit 27. The image processing unit 27 performs a decompression process on the image data from the memory card 35. The image processing unit 27 outputs the decompressed image data to the display control unit 30. The display control unit 30 converts the image data into video data and outputs it to the rear monitor 34. As a result, the user can view the playback image through the rear monitor 34.

[0037] The instruction receiving unit 32 receives various operation instructions from the user via the operation unit 21 and the touch panel 36 which is integrated with the rear monitor 34. The instruction receiving unit 32 outputs the received operation instructions to the control unit 20 via the bus line 28.

[0038] As described above, the operation unit 21 includes a field of view change switch, a shutter release button, and a mode switching switch. The shutter release button is a two-stage push button that can be half-pressed and fully pressed. Half-pressing the shutter release button instructs the camera to prepare for still image or video recording, and fully pressing it instructs the camera to start still image or video recording. In addition to these, the operation unit 21 also includes a menu button for displaying various setting menus on the rear monitor 34, a directional pad used for numerical settings and switching between options, and a confirmation button used to confirm settings. The touch panel 36 is superimposed on the display surface of the rear monitor 34. The touch panel 36 recognizes various operation instructions from the user by detecting contact with the user's finger or a dedicated indicator such as a stylus pen.

[0039] The modes that can be switched using the mode switch include still image shooting mode, video shooting mode, image playback mode, and settings mode. Still image shooting mode includes not only the normal shooting mode for taking a single still image, but also a continuous shooting mode that takes still images continuously at a predetermined shooting interval (for example, a frame rate of 5fps to 10fps). Continuous shooting mode is activated, for example, when the shutter release button is held fully pressed for a predetermined time or longer (for example, 1 second or more). Continuous shooting mode ends when the shutter release button is released.

[0040] As an example, as shown in Figure 2, the image sensor 12 is provided with a photoelectric conversion unit 40. The photoelectric conversion unit 40 is composed of a plurality of pixels 41 arranged two-dimensionally along the X and Y directions. The plurality of pixels 41 form an imaging surface 42. As is well known, the pixels 41 are composed of photoelectric conversion elements 47 such as microlenses 45, color filters 46, and photodiodes (see Figures 3 to 5). The X and Y directions are the horizontal and vertical directions when the bottom surface of the imaging device 10 is placed on a horizontal surface. In particular, the X direction is an example of a "phase difference detection direction" related to the technology of this disclosure. In this example, the Y direction is also a "phase difference detection direction".

[0041] Scan lines parallel to the X direction are wired between the rows of pixels 41. Signal lines parallel to the Y direction are wired between the columns of pixels 41. Each pixel 41 (photoelectric conversion element 47) is connected to the signal lines via an amplifier and a switch. The scan lines are also connected to the switch. In the case of storage operation, where a signal charge corresponding to the subject light is stored in the pixel 41 (photoelectric conversion element 47), an off signal is supplied as a vertical scan signal through the scan line, turning the switch off. In the case of readout operation, where an image signal (voltage signal) 43 corresponding to the signal charge is read from the pixel 41 (photoelectric conversion element 47), an on signal is supplied as a vertical scan signal through the scan line, turning the switch on. The ends of the signal lines are connected to a CDS (Correlated Double Sampling) circuit and an ADC (Analog to Digital Converter) circuit. The CDS circuit performs correlated double sampling on the image signal 43 input through the signal lines. The ADC circuit converts the image signal 43 after correlated double sampling into a digital image signal 43.

[0042] Pixels 41 are divided into three types depending on the type of color filter 46: green pixels (labeled "G" in Figure 2) that are sensitive to light in the green wavelength band, red pixels (labeled "R" in Figure 2) that are sensitive to light in the red wavelength band, and blue pixels (labeled "B" in Figure 2) that are sensitive to light in the blue wavelength band. The three types of pixels 41 are arranged regularly in a predetermined array. As a predetermined array, the so-called Bayer array is shown as an example, in which two green pixels, one blue pixel, and one red pixel are placed in a 2x2 pixel grid.

[0043] Pixel 41 consists of normal pixels 41N and phase-difference detection pixels 41P. Phase-difference detection pixels 41P are further divided into first phase-difference detection pixels 411P and second phase-difference detection pixels 412P. Normal pixels 41N come in three types: green, blue, and red, but phase-difference detection pixels 41P are only green.

[0044] The phase difference detection pixels 41P are arranged at predetermined intervals in the X and Y directions. In Figure 2, the phase difference detection pixels 41P are arranged at intervals of 5 pixels in the X direction and 2 pixels in the Y direction. Furthermore, the phase difference detection pixels 41P are arranged such that the first phase difference detection pixels 411P and the second phase difference detection pixels 412P appear alternately in the X and Y directions. For example, looking at the 4th row, the phase difference detection pixels 41P are arranged from left to right in the order of second phase difference detection pixel 412P, first phase difference detection pixel 411P, ... Also, for example, looking at the 10th column, the phase difference detection pixels 41P are arranged from top to bottom in the order of second phase difference detection pixel 412P, first phase difference detection pixel 411P, second phase difference detection pixel 412P, first phase difference detection pixel 411P, ... The first phase difference detection pixel 411P and the second phase difference detection pixel 412P, which are adjacent in the X and Y directions, constitute a set for detecting the phase difference α (see Figure 6).

[0045] As an example, as shown in Figures 3 to 5, the normal pixel 41N, the first phase difference detection pixel 411P, and the second phase difference detection pixel 412P have the same basic configuration and are composed of a microlens 45, a color filter 46, and a photoelectric conversion element 47 arranged in order from the object side.

[0046] As shown in Figure 3, the photoelectric conversion element 47 of the normal pixel 41N outputs an image generation signal 43N as an image signal 43, corresponding to the subject light that has been focused by the microlens 45 and passed through the color filter 46. The image generation signal 43N is stored in the image memory 26 as part of the image data.

[0047] As shown in Figures 4 and 5, a light-shielding member 49 is placed between the color filter 46 and the photoelectric conversion element 47 of the first phase difference detection pixel 411P and the second phase difference detection pixel 412P. This light-shielding member 49 is not normally placed in the pixel 41N. The light-shielding member 49 of the first phase difference detection pixel 411P shields the right half of the photoelectric conversion element 47 when viewed from the object side. In contrast, the light-shielding member 49 of the second phase difference detection pixel 412P shields the left half of the photoelectric conversion element 47 when viewed from the object side.

[0048] The photoelectric conversion element 47 of the first phase difference detection pixel 411P outputs a first calculation signal 431P as an image signal 43, corresponding to the subject light that is focused by the microlens 45, passes through the color filter 46, and whose right half is shielded by the light-shielding member 49. In contrast, the photoelectric conversion element 47 of the second phase difference detection pixel 412P outputs a second calculation signal 432P as an image signal 43, corresponding to the subject light that is focused by the microlens 45, passes through the color filter 46, and whose left half is shielded by the light-shielding member 49. The first calculation signal 431P and the second calculation signal 432P are stored in the image memory 26 as part of the image data, just like the image generation signal 43N. The first calculation signal 431P and the second calculation signal 432P are examples of "pixel values ​​of phase difference detection pixels" related to the technology of this disclosure. In the following, unless otherwise specified, the first calculation signal 431P and the second calculation signal 432P will be collectively referred to as calculation signal 43P.

[0049] As an example, as shown in Figure 6, a phase difference α appears between the first calculation signal 431P and the second calculation signal 432P output from the first phase difference detection pixel 411P and the second phase difference detection pixel 412P, which are adjacent in the X and Y directions. The phase difference α is also called parallax. This phase difference α indicates how much and in which direction the focus lens 14 needs to be moved to achieve the in-focus position. The imaging device 10 calculates the defocus amount DF (see Figure 22) based on the phase difference α and performs automatic focusing control to automatically move the focus lens 14 to a position that reduces the defocus amount DF, or more specifically, to a position that makes the defocus amount DF zero. The defocus amount DF is the difference between the position of the focus lens 14 on the optical axis OA, i.e., the current position of the focus lens 14, and the in-focus position. The defocus amount DF is an example of a "focus evaluation value" related to the technology of this disclosure.

[0050] As an example, as shown in Figure 7, the area 50 for calculating the defocus amount DF (hereinafter referred to as the focus adjustment area) is pre-set in the center of the imaging plane 42. The focus adjustment area 50 is a rectangular area that is long in the X direction, which is the phase difference detection direction. Multiple focus adjustment areas 50 are set; in this case, eight are set. The focus adjustment area 50 is an example of a "setting area" related to the technology of this disclosure.

[0051] The focus adjustment area 50 may be an area specified by the user, or an area surrounding a specific subject recognized by a well-known subject recognition technology. A specific subject may be the pupil, face, or torso of a person, the pupil, face, or torso of an animal, or the front or torso of a vehicle such as an automobile, railway car, or airplane. Here, the pupil of a person or animal refers to the pupil, or the black part of the eye. The face of a person or animal refers to the part that has the forehead, cheeks, chin, eyes, nose, mouth, ears, etc. The torso of a person or animal refers to the part excluding the head, neck, limbs, and tail. The front of a vehicle refers to the front body of an automobile, the part of a railway car that has the destination indicator, front windshield, headlights, etc. of the leading car, or the nose section of an airplane that has the radome, front windshield, etc. The torso of a vehicle refers to the entire body excluding the wheels of an automobile, the entire body excluding the wheels of a railway car, regardless of whether it is the leading car, middle car, or last car, or the entire body excluding the nose, main wings, tail wings, etc. of an airplane.

[0052] The image generation signal 43N, as its name suggests, is used to generate captured images such as live view images. In contrast, the calculation signal 43P is used only to calculate the phase difference α and, consequently, the defocus amount DF, and is not used to generate captured images. Therefore, in the pixel interpolation process, the image processing unit 27 interpolates the pixel value of the phase difference detection pixel 41P using the image generation signal 43N of the normal pixels 41N surrounding the phase difference detection pixel 41P.

[0053] Here, the calculation signal 43P is specifically divided into first calculation data DC1, shown in Figure 8(A) as an example, and second calculation data DC2, shown in Figure 8(B). The first calculation data DC1 is data obtained by arranging multiple first calculation signals 431P output from the first phase difference detection pixel 411P in a two-dimensional manner in the X and Y directions, following the arrangement of the first phase difference detection pixel 411P. The second calculation data DC2 is data obtained by arranging multiple second calculation signals 432P output from the second phase difference detection pixel 412P in a two-dimensional manner in the X and Y directions, following the arrangement of the second phase difference detection pixel 412P. These first calculation data DC1 and second calculation data DC2 can be treated as two-dimensional image data. In the following, unless there is a particular need to distinguish between them, the first calculation data DC1 and the second calculation data DC2 will be collectively referred to as calculation data DC.

[0054] As an example, as shown in Figure 9, the control unit 20 includes storage 55, a CPU (Central Processing Unit) 56, and memory 57. These storage 55, CPU 56, and memory 57 are interconnected via a bus line 58. The control unit 20 is an example of a "focusing control device" and "computer" according to the technology of this disclosure.

[0055] Storage 55 is a non-volatile storage device, such as EEPROM (Electrically Erasable Programmable Read-Only Memory). Storage 55 stores various programs and various data associated with those programs. Alternatively, FeRAM (Ferroelectric Random Access Memory) or MRAM (Magnetoresistive Random Access Memory) may be used as storage 55 instead of EEPROM.

[0056] Memory 57 is a work memory for the CPU 56 to execute processing. The CPU 56 loads the program stored in storage 55 into memory 57 and executes processing according to the program. In this way, the CPU 56 comprehensively controls each part of the imaging device 10. CPU 56 is an example of a "processor" related to the technology of this disclosure. Note that memory 57 may be built into the CPU 56.

[0057] As an example, as shown in Figure 10, the storage 55 stores an operating program 65. The operating program 65 is a program that causes the CPU 56 to perform automatic focusing control, etc. In other words, the operating program 65 is an example of an "operating program for a focusing control device" related to the technology of this disclosure. The storage 55 also stores a first switching condition 661, a second switching condition 662, and an adoption condition 67. The adoption condition 67 is an example of a "condition" related to the technology of this disclosure.

[0058] When the operating program 65 is started, the CPU 56 works in cooperation with the memory 57 and other components to function as the focus control unit 68. The focus control unit 68 includes a focus calculation unit 70, a mode switching setting unit 71, an acceptance / rejection determination unit 72, a distance detection unit 73, and a focus lens drive control unit 74. In addition to the focus control unit 68, the CPU 56 also functions as various other processing units.

[0059] The focus control unit 68 receives the drive amount 80 of the focus motor from the focus lens drive mechanism 17. The focus control unit 68 derives the current position of the focus lens 14 from the drive amount 80.

[0060] The focus calculation unit 70 reads calculation data DC from the image memory 26. The focus calculation unit 70 detects the phase difference α shown in Figure 6 from the calculation data DC of the focus adjustment area 50. The focus calculation unit 70 converts the phase difference α into a defocus amount DF. The focus calculation unit 70 outputs the focus calculation result 81, including the calculated defocus amount DF, to the mode switching setting unit 71, the acceptance / rejection determination unit 72, and the focus lens drive control unit 74. Note that the method for converting the phase difference α into a defocus amount DF is well known, so a detailed explanation is omitted here.

[0061] The mode switching setting unit 71 receives the first switching condition 661 and the second switching condition 662 as input. Based on these first and second switching conditions 661 and the focus calculation result 81, the mode switching setting unit 71 sets one of two modes: non-pixel addition mode and pixel addition mode. The non-pixel addition mode is a mode in which the calculation signal 43P, which is the pixel value of the calculation data DC, is used as is without addition. The pixel addition mode is a mode in which the calculation signal 43P is added (see Figure 12). The mode switching setting unit 71 outputs the mode setting information 82 to the focus calculation unit 70.

[0062] The acceptance / rejection determination unit 72 receives the acceptance conditions 67 as input. Based on these acceptance conditions 67, the acceptance / rejection determination unit 72 determines whether or not to accept the defocus amount DF included in the focus calculation result 81 output in pixel addition mode as the suitable defocus amount ADF. The suitable defocus amount ADF is the defocus amount DF used in the distance detection unit 73 for detecting the distance of the target subject (hereinafter referred to as subject distance) and, consequently, for focus control. The suitable defocus amount ADF is an example of a "focus evaluation value that satisfies pre-set conditions" relating to the technology of this disclosure.

[0063] The subject distance is, for example, the distance from the imaging surface 42 to the target subject. The target subject is a subject that is located in the focus adjustment area 50. The acceptance / rejection determination unit 72 outputs the acceptance / rejection determination result 83 to the distance detection unit 73.

[0064] The acceptance / rejection determination unit 72 outputs the focus calculation result 81 output in non-pixel addition mode to the distance detection unit 73 as is without making a determination. The distance detection unit 73 unconditionally treats the defocus amount DF included in the focus calculation result 81 output in non-pixel addition mode as the suitable defocus amount ADF and uses it to detect the subject distance.

[0065] The distance detection unit 73 detects the subject distance from the adapted defocus amount ADF. The adapted defocus amount ADF handled by the distance detection unit 73 is, for example, calculated 1 to 3 frames ago. The subject distance detected by the distance detection unit 73 is, for example, the distance corresponding to the position where the subject is predicted to be present in the next frame. In other words, the distance detection unit 73 predicts the future subject distance from the defocus amount DF calculated in the past. The distance detection unit 73 stores a predetermined number of defocus amounts DF (hereinafter referred to as the required number) necessary for detecting the subject distance for multiple consecutive frames. The method for detecting the subject distance from the defocus amount DF is well known, so a detailed explanation is omitted here. The distance detection unit 73 outputs the subject distance detection result 84 to the focus calculation unit 70.

[0066] The focus lens drive control unit 74 controls the drive of the focus lens drive mechanism 17 and, consequently, the focus lens 14. Specifically, the focus lens drive control unit 74 moves the focus lens 14 to an estimated focus position corresponding to the calculated defocus amount DF, based on the current position derived from the drive amount 80, via the focus lens drive mechanism 17. Here, when the focus lens drive control unit 74 moves the focus lens 14, it means that the focus lens drive control unit 74 sends a drive signal to the driver of the focus motor of the focus lens drive mechanism 17, causing the focus motor to move the focus lens 14. If the current position of the focus lens 14 and the estimated focus position are the same (defocus amount DF is 0), the focus lens drive control unit 74 does nothing, and the focus lens 14 is not moved.

[0067] The focus control unit 68 performs the focus calculation by the focus calculation unit 70 and the drive control of the focus lens 14 by the focus lens drive control unit 74 for each frame. Therefore, the focus calculation result 81 from the focus calculation unit 70 is updated for each frame. Consequently, the number of times the focus calculation result 81 is output per unit time is 1 time / frame.

[0068] As an example, as shown in Figure 11, the focus calculation unit 70 includes a mode switching unit 90, a pixel addition unit 91, a correlation calculation unit 92, and a defocus amount calculation unit 93. The mode switching unit 90 receives first calculation data DC1 and second calculation data DC2, and setting information 82 as input. If the setting information 82 indicates that the mode should be set to non-pixel addition mode, the mode switching unit 90 outputs the first calculation data DC1 and second calculation data DC2 to the correlation calculation unit 92. On the other hand, if the setting information 82 indicates that the mode should be set to pixel addition mode, the mode switching unit 90 outputs the first calculation data DC1 and second calculation data DC2 to the pixel addition unit 91.

[0069] A filter processing unit (not shown) is provided prior to the mode switching unit 90. The filter processing unit performs filtering by passing the first calculation data DC1 and the second calculation data DC2 through a bandpass filter. The first calculation data DC1 and the second calculation data DC2 after this filtering are input to the mode switching unit 90.

[0070] The pixel addition unit 91 performs pixel addition on the first calculation data DC1 and the second calculation data DC2 to obtain the added first calculation data DCA1 and the added second calculation data DCA2. The pixel addition unit 91 outputs the added first calculation data DCA1 and the added second calculation data DCA2 to the correlation calculation unit 92. In the following, unless otherwise necessary, the added first calculation data DCA1 and the added second calculation data DCA2 will be collectively referred to as the added calculation data DCA.

[0071] In non-pixel summation mode, the correlation calculation unit 92 performs a correlation calculation between the first calculation data DC1 and the second calculation data DC2. In pixel summation mode, the correlation calculation unit 92 performs a correlation calculation between the summed first calculation data DCA1 and the summed second calculation data DCA2. The correlation calculation unit 92 outputs the correlation calculation result 95 to the defocus amount calculation unit 93.

[0072] The defocus amount calculation unit 93 calculates the defocus amount DF based on the correlation calculation result 95. Furthermore, if the defocus amount calculation unit 93 receives a detection result 84 from the distance detection unit 73, it calculates the defocus amount DF corresponding to the subject distance included in the detection result 84.

[0073] As an example, as shown in Figure 12(A), the pixel addition unit 91 generates the first calculation data DCA1 after addition by repeatedly adding and averaging the first calculation signals 431P for four pixels connected in the X direction, which is the phase difference detection direction, as a pixel addition process. Similarly, as shown in (B), the pixel addition unit 91 generates the second calculation data DCA2 after addition by repeatedly adding and averaging the second calculation signals 432P for four pixels connected in the X direction, as a pixel addition process. The number of pixels in the calculation data DCA after addition is compressed to 1 / 4 of the number of pixels in the calculation data DC. Therefore, the calculation data DCA after addition becomes data in which the intensity of the frequency components is pseudo-shifted to the high-frequency side. The first calculation signal 441P of the first calculation data DCA1 after addition and the second calculation signal 442P of the second calculation data DCA2 after addition are examples of "added values" related to the technology of this disclosure.

[0074] As an example, as shown in Figure 13, in the non-pixel summation mode, the correlation calculation unit 92 fixes the first calculation data DC1 of the focus adjustment region 50 and shifts the second calculation data DC2 of the focus adjustment region 50 by one pixel in the X direction, which is the phase difference detection direction. Each time it is shifted, it calculates the sum of squared differences between the first calculation data DC1 and the second calculation data DC2 of the focus adjustment region 50. On the other hand, in the pixel summation mode, the correlation calculation unit 92 fixes the first calculation data DCA1 after summation of the focus adjustment region 50 and shifts the second calculation data DCA2 after summation of the focus adjustment region 50 by one pixel in the X direction. Each time it is shifted, it calculates the sum of squared differences between the first calculation data DCA1 and the second calculation data DCA2 after summation of the focus adjustment region 50. Note that instead of the sum of squared differences, the sum of absolute differences or the normalized cross-correlation may be calculated.

[0075] Graph 100 plots the shift amount of the second calculation data DC2 or the added second calculation data DCA2 on the horizontal axis and the sum of squared differences on the vertical axis. In Graph 100, the correlation curve CC is formed by connecting the plots of the sum of squared differences for each shift amount with lines. In this correlation curve CC, the shift amount at which the sum of squared differences is minimized is the phase difference α. The correlation calculation unit 92 outputs a correlation calculation result 95 that includes the phase difference α.

[0076] The correlation calculation unit 92 performs the above correlation calculation for each focus adjustment region 50. As a result, multiple correlation curves CC are obtained for each focus adjustment region 50; in this example, eight correlation curves CC are obtained. The correlation calculation unit 92 aggregates the multiple correlation curves CC into a single correlation curve CC by means of averaging the multiple correlation curves CC. Then, it detects the phase difference α from the aggregated single correlation curve CC.

[0077] Let's consider the scenario shown in Figure 14 as an example. Specifically, (A) shows the case where a video is being filmed with a distant mountain 102 as the subject. From the state shown in (A), if the subject is switched from the distant mountain 102 to the foreground person 103, as shown in (B), the subject distance changes significantly.

[0078] As shown in Figure 14, when the subject distance fluctuates significantly, the movement of the focus lens 14 to the estimated focus position may not keep up, resulting in a significantly blurred image. In such a significantly blurred state, as shown in Figure 15 as an example, the waveform of the correlation curve CC obtained by the correlation calculation of the first calculation data DC1 and the second calculation data DC2 becomes distorted, and multiple local minima of the sum of squared differences appear. From such a correlation curve CC, it is not possible to detect the phase difference α, and therefore the defocus amount DF cannot be calculated.

[0079] In contrast, as shown in Figure 16 as an example, by performing pixel addition processing, the correlation curve CC obtained by the correlation calculation of the first calculation data DCA1 and the second calculation data DCA2 after addition shows reduced waveform distortion. This makes it possible to detect the phase difference α, and consequently, to calculate the defocus amount DF. However, since the calculation data DCA after addition compresses the pixel values, the accuracy of calculating the defocus amount DF is lower compared to the non-pixel addition mode that uses the calculation data DC. Thus, the pixel addition mode is provided to overcome situations where the subject distance fluctuates greatly, resulting in significant blurring, and it becomes impossible to calculate the defocus amount DF and perform automatic focusing control. For this reason, in pixel addition mode, a slight decrease in the accuracy of calculating the defocus amount DF is not a concern.

[0080] As an example, as shown in Figure 17, the first switching condition 661 is that the number of consecutive times the defocus amount DF cannot be calculated by the defocus amount calculation unit 93 is equal to or greater than the first threshold count THT1. The first threshold count THT1 is, for example, 3 times. The mode switching setting unit 71 outputs setting information 82 that, if the first switching condition 661 is met in the non-pixel addition mode, the mode is set to the pixel addition mode. As a result, the mode switching unit 90 switches the mode from the non-pixel addition mode to the pixel addition mode.

[0081] The second switching condition 662 is that the defocus amount DF calculated by the defocus amount calculation unit 93 is less than or equal to the first threshold amount THA1. The first threshold amount THA1 is, for example, 1 / 10 of the maximum value of the defocus amount DF. The mode switching setting unit 71 outputs setting information 82 that, if the second switching condition 662 is met in the pixel addition mode, the mode will be set to non-pixel addition mode. As a result, the mode switching unit 90 switches the mode from pixel addition mode to non-pixel addition mode.

[0082] As an example, as shown in Figure 18, adoption condition 67 states that a defocus amount DF less than or equal to the second threshold amount THA2 shall be considered a suitable defocus amount ADF. The second threshold amount THA2 is a value greater than the first threshold amount THA1 and is, for example, 1 / 5 of the maximum value of the defocus amount DF. The second threshold amount THA2 is an example of the "first threshold" related to the technology of this disclosure. Furthermore, a value less than or equal to the second threshold amount THA2 is an example of being "within the first threshold range" related to the technology of this disclosure.

[0083] As an example, as shown in Figure 19, in pixel addition mode, the defocus amount DF (represented as defocus amount Z in Figure 19, and similarly in Figure 20) is calculated from the defocus amount calculation unit 93, and if the defocus amount DF satisfies the adoption condition 67, the adoption determination unit 72 outputs an adoption determination result 83 indicating that the defocus amount DF is adopted as the suitable defocus amount ADF. In this case, the adoption determination unit 72 includes the defocus amount DF in the adoption determination result 83.

[0084] On the other hand, as shown in Figure 20 as an example, in the pixel addition mode, if the defocus amount DF is calculated by the defocus amount calculation unit 93 but does not satisfy the acceptance condition 67, the acceptance / rejection determination unit 72 outputs an acceptance / rejection determination result 83 indicating that it is not accepted.

[0085] As shown in Figures 19 and 20, if the defocus amount DF is calculated by the defocus amount calculation unit 93, the focus calculation result 81 includes the calculated defocus amount DF. Conversely, if the defocus amount DF cannot be calculated, the focus calculation result 81 naturally does not include the defocus amount DF and indicates that the defocus amount DF could not be calculated.

[0086] As an example, as shown in Figure 21(A), if there are the required number of compatible defocus amount ADFs, the distance detection unit 73 detects the subject distance. Conversely, as shown in (B), if there are not the required number of compatible defocus amount ADFs, the distance detection unit 73 does not detect the subject distance. The required number varies depending on the mode. Specifically, the required number is 2 in pixel addition mode and 3 in non-pixel addition mode.

[0087] Figure 22 shows the changes in the current position of the focus lens 14 and the estimated focus position when the subject is switched from a distant to a close-up in time TA in non-pixel summation mode. Switching the subject from a distant to a close-up refers to a situation where the subject distance changes significantly, as shown in Figure 14. In such situations, it becomes impossible to calculate the defocus amount DF, as shown in Figure 15. Therefore, in time TA, the defocus amount DF cannot be calculated, and the estimated focus position cannot be detected.

[0088] Even during time TB and time TC after time TA, the state in which the defocus amount DF cannot be calculated continues. If this state in which the defocus amount DF cannot be calculated continues for three consecutive times and the first switching condition 661 is met, the mode switching unit 90 switches the mode from non-pixel addition mode to pixel addition mode, as shown in Figure 17.

[0089] In the first time TD after switching to pixel addition mode, the defocus amount DF is calculated from the defocus amount calculation unit 93 and the estimated focus position PD is detected. In pixel addition mode, the accuracy of calculating the defocus amount DF decreases, so the estimated focus position PD deviates from the original focus position of the foreground shown by the dashed line. Under the control of the focus lens drive control unit 74, the movement of the focus lens 14 toward the estimated focus position PD is started at a preset speed in order to reduce the defocus amount DF.

[0090] At time TD, the current position of the focus lens 14 and the estimated focus position PD are far apart, so the defocus amount DF calculated at time TD does not satisfy the acceptance condition 67. For this reason, the acceptance / rejection determination unit 72 determines that the defocus amount DF calculated at time TD will not be accepted as the suitable defocus amount ADF, as shown in Figure 20.

[0091] In the subsequent time TE, the defocus amount DF is calculated by the defocus amount calculation unit 93 and the estimated focus position PE is detected. However, the current position of the focus lens 14 and the estimated focus position PD are still far apart, so the defocus amount DF does not meet the acceptance condition 67. For this reason, the acceptance / rejection determination unit 72 determines that the defocus amount DF calculated in time TE will not be accepted as a suitable defocus amount ADF.

[0092] As the focus lens 14 moves towards the estimated focus position, the blurred state is gradually resolved. This restores the detection accuracy of the phase difference α, and consequently the calculation accuracy of the defocus amount DF, causing the estimated focus position to gradually converge to the original focus position. Therefore, at time TE, the estimated focus position PE is updated to be closer to the original focus position than the estimated focus position PD at time TD.

[0093] During time TF, the defocus amount DF is calculated from the defocus amount calculation unit 93, and an estimated focus position PF that is closer to the original focus position is detected. In this case, the defocus amount DF satisfies the acceptance condition 67. Therefore, the acceptance / rejection determination unit 72 determines that the defocus amount DF calculated during time TF is to be accepted as the suitable defocus amount ADF, as shown in Figure 19.

[0094] Between time TA and time TF, there are no required number (in this case, two) of compatible defocus amount ADFs. Therefore, between time TA and time TF, as shown in Figure 21(B), the distance detection unit 73 does not detect the subject distance.

[0095] During time TG, the defocus amount DF is calculated by the defocus amount calculation unit 93, and an estimated focus position PG that is almost identical to the original focus position is detected. In this case, the defocus amount DF also satisfies the acceptance condition 67. Therefore, the acceptance / rejection determination unit 72 determines that the defocus amount DF calculated during time TG is also to be accepted as the suitable defocus amount ADF.

[0096] Furthermore, the amount of defocus DF in time TG satisfies the second switching condition 662. When the second switching condition 662 is satisfied, the mode is switched from pixel addition mode to non-pixel addition mode by the mode switching unit 90, as shown in Figure 17.

[0097] In time TG, there are two adapted defocus amounts ADF: the defocus amount DF in the previous time TF and the defocus amount DF in the current time TG. Therefore, in time TG, as shown in Figure 21(A), the distance detection unit 73 detects the subject distance.

[0098] At the first time TH after switching to non-pixel summing mode, the defocus amount calculation unit 93 calculates a defocus amount DF corresponding to the subject distance detected at time TG, and the estimated focus position PH is detected. The estimated focus position PH coincides with the original focus position. Also at time TH, the focus lens 14 reaches the estimated focus position PH. Under the control of the focus lens drive control unit 74, the focus lens 14 is stopped at the estimated focus position PH. In this way, the focus lens 14 is moved to the estimated focus position PH, which is a position corresponding to the subject distance detected using the defocus amount DF at time TF and time TG, which is the adapted defocus amount ADF. Note that "stop" does not mean to permanently stop the focus lens 14 at a specific position, but rather to stop it temporarily.

[0099] As an example, as shown in Figure 23, at time TH, there are three adapted defocus amounts ADF: the defocus amounts DF at times TF and TG, and the defocus amount DF at time TH. Therefore, at time TH, the distance detection unit 73 detects the distance to the subject.

[0100] At time TI following time TH, the defocus amount calculation unit 93 calculates a defocus amount DF corresponding to the subject distance detected at time TH, and the estimated focus position PI is detected. The estimated focus position PI, like the estimated focus position PH, coincides with the original focus position. Under the control of the focus lens drive control unit 74, the focus lens 14 is kept at the estimated focus position PI. In this way, even when switching from pixel addition mode to non-pixel addition mode, the subject distance is detected using both the adapted defocus amount ADF obtained in the pixel addition mode and the adapted defocus amount ADF obtained in the non-pixel addition mode.

[0101] The estimated focus position is updated over time as PD, PE, PF, PG, PH, etc. Under the control of the focus lens drive control unit 74, the focus lens 14 is moved toward this estimated focus position that is updated over time.

[0102] As an example, the transition between the current position of the focus lens 14 and the estimated focus position shown in Figure 24 represents a case in non-pixel summation mode where the subject is switched from a distant to a close-up, and the close-up subject is moving. In this case as well, for example, at time TH, the subject distance is detected using the defocus amount DF at times TF, TG, and TH, which are adopted as the adapted defocus amount ADF. Then, at time TI, the defocus amount calculation unit 93 calculates the defocus amount DF according to the subject distance detected at time TH, and the estimated focus position PI is detected. By detecting the subject distance using the adapted defocus amount ADF obtained in pixel summation mode, it is possible to predict the distance according to the future position of the moving subject, making it easier to focus on the moving subject.

[0103] Next, the operation of the above configuration will be explained with reference to the flowchart shown in Figure 25 as an example. As shown in Figure 10, the CPU 56 of the control unit 20 functions as a focus control unit 68 when the operation program 65 is activated. The focus control unit 68 includes a focus calculation unit 70, a mode switching setting unit 71, an acceptance / rejection determination unit 72, a distance detection unit 73, and a focus lens drive control unit 74. Also, as shown in Figure 11, the focus calculation unit 70 includes a mode switching unit 90, a pixel addition unit 91, a correlation calculation unit 92, and a defocus amount calculation unit 93.

[0104] When the shutter release button is fully pressed in video recording mode and the instruction to start video recording is received by the instruction reception unit 32, the image sensor 12 performs an operation to accumulate signal charge according to the subject light under the control of the control unit 20. Subsequently, an image signal 43 corresponding to the signal charge is read out. The image signal 43 is stored in the image memory 26 via the image input controller 25. After various image processing is performed by the image processing unit 27, the image signal 43 is written back to the image memory 26. Immediately after starting video recording, the mode switching unit 90 is set to non-pixel addition mode.

[0105] Calculation data DC is read from the image memory 26 to the focus calculation unit 70. Then, as shown in Figure 13, the focus calculation unit 70 detects the phase difference α from the calculation data DC of the focus adjustment region 50, and calculates the defocus amount DF from the phase difference α. The focus calculation result 81 is output from the focus calculation unit 70 to the mode switching setting unit 71, the acceptance / rejection determination unit 72, and the focus lens drive control unit 74. In addition, the focus control unit 68 derives the current position of the focus lens 14 based on the drive amount 80 of the focus motor from the focus lens drive mechanism 17.

[0106] If the first switching condition 661 is met, setting information 82 indicating that the mode switching setting unit 71 is set to pixel addition mode is output to the focus calculation unit 70. The focus calculation unit 70 outputs calculation data DC from the mode switching unit 90 to the pixel addition unit 91.

[0107] In the pixel addition unit 91, as shown in Figure 12, pixel addition processing is performed on the calculation data DC (step ST100). The added calculation data DCA is output from the pixel addition unit 91 to the correlation calculation unit 92.

[0108] In the correlation calculation unit 92, as shown in Figure 13, a correlation calculation is performed between the first calculation data DCA1 and the second calculation data DCA2 after addition in the focus adjustment region 50, and the phase difference α is detected (step ST110). The correlation calculation result 95 is output from the correlation calculation unit 92 to the defocus amount calculation unit 93.

[0109] In the defocus amount calculation unit 93, the defocus amount DF is calculated based on the correlation calculation result 95 (step ST120).

[0110] In the acceptance / rejection determination unit 72, it is determined whether the defocus amount DF included in the focus calculation result 81 is a suitable defocus amount ADF that satisfies the acceptance condition 67 (step ST130). If the defocus amount DF is a suitable defocus amount ADF (YES in step ST140) and there are the required number of suitable defocus amounts ADF (YES in step ST150), the distance detection unit 73 detects the subject distance using the suitable defocus amount ADF (step ST160). The subject distance detection result 84 is output from the distance detection unit 73 to the defocus amount calculation unit 93 of the focus calculation unit 70.

[0111] In the defocus amount calculation unit 93, a defocus amount DF is calculated according to the subject distance included in the detection result 84. Then, under the control of the focus lens drive control unit 74, the focus lens 14 is moved to a position corresponding to the subject distance (step ST170). In other words, focusing control is performed using the adapted defocus amount ADF.

[0112] If the defocus amount DF is not the correct defocus amount ADF (NO in step ST140), and if there are not enough correct defocus amounts ADF (NO in step ST150), the focus lens 14 is moved to a position corresponding to the most recently calculated defocus amount DF under the control of the focus lens drive control unit 74.

[0113] As described above, the imaging device 10 includes a control unit 20, which is a focus control device that controls the focusing of the focus lens 14 based on the output from the phase difference detection pixel 41P. The CPU 56 of the control unit 20 functions as a focus control unit 68. The focus control unit 68 includes a focus calculation unit 70 and a focus lens drive control unit 74.

[0114] The focusing calculation unit 70 obtains the defocus amount DF by calculating it according to the added first calculation signal 441P and the added second calculation signal 442P, which are the sum of the calculation signals 43P of the calculation data DC, which are the pixel values ​​of a plurality of phase difference detection pixels 41P. The focusing lens drive control unit 74 performs focusing control using the adapted defocus amount ADF, which is the defocus amount DF that satisfies the adoption condition 67.

[0115] The defocus amount DF calculated in pixel-addition mode has lower calculation accuracy than the defocus amount DF calculated in non-pixel-addition mode. However, some defocus amounts DF calculated in pixel-addition mode have calculation accuracy comparable to those calculated in non-pixel-addition mode. Therefore, in the technology disclosed herein, the defocus amount DF calculated in pixel-addition mode is divided into suitable defocus amount ADF and non-suitable defocus amount ADF according to the adoption condition 67, and the subject distance is detected using the suitable defocus amount ADF. By doing so, it is possible to suppress the decrease in the accuracy of subject distance detection compared to the case where all of the defocus amount DF calculated in pixel-addition mode is used without any constraints to detect the subject distance.

[0116] The distance detection unit 73 detects the subject distance based on the appropriate defocus amount ADF. The focus lens drive control unit 74 performs focusing control according to the subject distance. Therefore, focusing control according to the subject distance, which has relatively high detection accuracy, can be performed.

[0117] As shown in Figure 18, the adoption condition 67 is that the defocus amount DF, which is the difference between the current position of the focus lens 14 and the in-focus position of the focus lens 14, is less than or equal to the second threshold amount THA2. Therefore, it is possible to easily determine whether the defocus amount DF is the appropriate defocus amount ADF.

[0118] In this example, the defocus amount DF, which is the difference between the current position and the in-focus position of the focus lens 14, is used as the focus evaluation value. The defocus amount DF is a very common value and its calculation method is well established, making it suitable as a focus evaluation value. Alternatively, the phase difference α may be used as the focus evaluation value instead of the defocus amount DF.

[0119] As shown in Figure 17, the mode switching unit 90 switches between a pixel addition mode in which the calculation signal 43P is added and a non-pixel addition mode in which the calculation signal 43P is not added. Therefore, in the non-pixel addition mode, if the subject distance fluctuates greatly as shown in Figure 14 and it becomes impossible to calculate the defocus amount DF, the situation can be resolved by switching to the pixel addition mode.

[0120] The focus lens drive control unit 74 does not perform focusing control using the appropriate defocus amount ADF if there is no appropriate defocus amount ADF. Therefore, it is possible to suppress the deterioration of the quality of focusing control compared to when the subject distance is forcibly detected using the set value of the defocus amount DF instead of the calculated defocus amount DF, and focusing control is performed according to the detected subject distance.

[0121] As shown in Figure 12, the pixel summing unit 91 adds the calculation signals 43P of the phase difference detection pixels 41P that are connected in the X direction, which is the phase difference detection direction. Therefore, the post-sum calculation data DCA can be treated in the same way as the calculation data DC, and the detection of the phase difference α and the calculation of the defocus amount DF based on the post-sum calculation data DCA can be performed without any problems.

[0122] [Second Embodiment] As an example, as shown in Figure 26, if the speed of the focus lens 14 is relatively fast, or if the subject is moving, there is a risk that the number of compatible defocus amounts (ADF) will not be sufficient (3 in Figure 26). In such cases, as an example, as shown in Figure 27, the focus lens drive control unit 74 sets the speed of the focus lens 14 to a speed that can secure the required number of compatible defocus amounts (ADF) at the timing (time TG in Figure 27) when it is determined that the defocus amount DF satisfies the second switching condition 662 and to switch from pixel addition mode to non-pixel addition mode. Specifically, the focus lens drive control unit 74 sets the speed of the focus lens 14 to a slower speed. The speed that can secure the required number of compatible defocus amounts (ADF) is the speed related to the vector sum of the vector of the movement trajectory that the focus lens 14 would have followed at the original speed and the vector parallel to the time axis for one output (one frame) of the focus calculation result 81. Note that the vector parallel to the time axis becomes longer as the required number increases, and the speed of the focus lens 14 is set to a slower speed.

[0123] By setting the speed of the focus lens 14 to a slower setting, it is possible to obtain the defocus amount DF at time TI, in addition to the fitted defocus amount ADF at time TG and the defocus amount ADF at time TH. This allows for the detection of the subject distance at time TI using the three fitted defocus amounts ADF at time TG, TH, and TI. As a result, at time TJ, the defocus amount DF corresponding to the subject distance detected at time TI is calculated, and the estimated focus position PJ is detected.

[0124] Thus, in the second embodiment, the focus lens drive control unit 74 sets the speed of the focus lens 14 to a speed that can secure the required number of correct defocus amounts ADF. Therefore, the required number of correct defocus amounts ADF can be secured regardless of the speed of the focus lens 14, and the focus lens 14 can be moved to a position corresponding to the subject distance. In addition, by normally setting the speed of the focus lens 14 to the fastest setting and only setting the speed of the focus lens 14 to a slower setting when it is not possible to secure the required number of correct defocus amounts ADF, it is possible to avoid slowing down the normal automatic focusing control speed.

[0125] [Third Embodiment] As an example, as shown in Figure 28, the adoption condition 110 of the third embodiment is to set the defocus amount DF calculated after the second threshold count THT2 following the switch from non-pixel addition mode to pixel addition mode as the appropriate defocus amount ADF. The second threshold count THT2 is, for example, 3 times. The adoption condition 110 is an example of a "condition" relating to the technology of this disclosure. The second threshold count THT2 is an example of a "first threshold count" relating to the technology of this disclosure.

[0126] Since the acceptance condition 110 is as described above, in the third embodiment, the acceptance / rejection determination unit 72 determines that the defocus amount DF calculated from the time set after switching from the non-pixel addition mode to the pixel addition mode is not the suitable defocus amount ADF. Therefore, in this case, the distance detection unit 73 does not detect the subject distance. The set time is from the time of switching to the pixel addition mode until the defocus amount DF of the second threshold count THT2 is calculated.

[0127] As an example, as shown in Figure 29, the time TD when switching from non-pixel addition mode to pixel addition mode, and the following time TE, are before the set time has elapsed. Therefore, the acceptance / rejection determination unit 72 does not accept the defocus amount DF at time TD and TE as the suitable defocus amount ADF. For this reason, the distance detection unit 73 does not detect the subject distance at time TD and TE.

[0128] Time TF and the following time TG occur after the second threshold count THT2 following the switch from non-pixel addition mode to pixel addition mode. Therefore, the acceptance / rejection determination unit 72 adopts the defocus amount DF in time TF and TG as the appropriate defocus amount ADF. The distance detection unit 73 uses the appropriate defocus amount ADF in time TF and TG to detect the subject distance. As a result, at time TH, the defocus amount DF corresponding to the subject distance detected in time TG is calculated, and the estimated focus position PH is detected.

[0129] Thus, in the third embodiment, the adoption condition 110 is to use the defocus amount DF calculated after the second threshold count THT2 following a switch from the non-pixel addition mode to the pixel addition mode as the appropriate defocus amount ADF. Therefore, the subject distance can be detected using the defocus amount DF, which has relatively high calculation accuracy. In addition, in the third embodiment, the adoption / rejection determination unit 72 determines that the defocus amount DF calculated from the time set after switching from the non-pixel addition mode to the pixel addition mode is not the appropriate defocus amount ADF. Therefore, it is possible to prevent the subject distance from being detected using the defocus amount DF, which has relatively low calculation accuracy, and thus prevent the prediction of an incorrect subject distance. The third embodiment also makes it possible to suppress the decrease in the accuracy of subject distance detection compared to the case where all of the defocus amount DF calculated in the pixel addition mode is used to detect the subject distance without any restrictions.

[0130] [Fourth Embodiment] As an example, as shown in Figure 30, in the fourth embodiment, a contrast value calculation unit 120 is provided before the acceptance / rejection determination unit 72. Focus adjustment area data 121 is input to the contrast value calculation unit 120. Focus adjustment area data 121 is a collection of image generation signals 43N output from normal pixels 41N present in the focus adjustment area 50. The contrast value calculation unit 120 calculates the contrast value CV of the focus adjustment area data 121 and outputs the calculated contrast value CV to the acceptance / rejection determination unit 72. Since there are multiple focus adjustment areas 50, the contrast value calculation unit 120 calculates the contrast value CV for each of the multiple focus adjustment areas 50 and outputs their average value to the acceptance / rejection determination unit 72. The contrast value CV is the so-called luminance contrast, and in this case it is the ratio of the relative luminance of the brightest color to the relative luminance of the darkest color in the focus adjustment area data 121.

[0131] In the fourth embodiment, adoption condition 122 is that the defocus amount DF calculated when the contrast value CV is equal to or greater than the contrast threshold THCV is set as the appropriate defocus amount ADF. Adoption condition 122 is an example of a "condition" relating to the technology of this disclosure. The contrast threshold THCV is an example of a "second threshold range" relating to the technology of this disclosure. Furthermore, being equal to or greater than the contrast threshold THCV is an example of being "within the second threshold range" relating to the technology of this disclosure.

[0132] The acceptance / rejection determination unit 72 determines that the defocus amount DF calculated when the contrast value CV is equal to or greater than the contrast threshold THCV will be accepted as the suitable defocus amount ADF. Conversely, the acceptance / rejection determination unit 72 determines that the defocus amount DF calculated when the contrast value CV is less than the contrast threshold THCV will not be accepted as the suitable defocus amount ADF.

[0133] Thus, in the fourth embodiment, the contrast value calculation unit 120 determines the contrast value CV in the focus adjustment region 50. The adoption condition 122 is that the defocus amount DF calculated when the contrast value CV is equal to or greater than the contrast threshold THCV is used as the appropriate defocus amount ADF. Generally, as the focus lens 14 approaches the focus position, the contrast value CV increases, and the calculation accuracy of the defocus amount DF also increases. Therefore, by setting the constraint that the contrast value CV is equal to or greater than the contrast threshold THCV, the subject distance can be detected using the defocus amount DF, which has relatively high calculation accuracy. Accordingly, even in the fourth embodiment, it is possible to suppress the decrease in the accuracy of subject distance detection compared to the case where all of the defocus amount DF calculated in the pixel addition mode is used to detect the subject distance without any constraints.

[0134] Note that the setting area is not limited to the example focus adjustment area 50. It may be the entire imaging surface 42. Also, if the imaging device 10 has a function for automatic focus control using the contrast method, the contrast value CV derived in the automatic focus control using the contrast method may be reused.

[0135] [Fifth Embodiment] As an example, as shown in Figure 31, in the fifth embodiment, a frequency intensity calculation unit 125 is provided before the adoption / rejection determination unit 72. Focus adjustment region data 121 is input to the frequency intensity calculation unit 125. The frequency intensity calculation unit 125 performs a well-known frequency analysis, such as a Fourier transform, on the focus adjustment region data 121 to obtain the intensity FS of each frequency component in a preset frequency band of the focus adjustment region data 121, and outputs the obtained intensity FS to the adoption / rejection determination unit 72. The preset frequency band is, for example, 1 Hz to 1000 Hz. Since there are multiple focus adjustment regions 50, the frequency intensity calculation unit 125 obtains the intensity FS for each of the multiple focus adjustment regions 50 and outputs their average value to the adoption / rejection determination unit 72.

[0136] The adoption condition 126 in the fifth embodiment is that the defocus amount DF calculated when the intensity FS at the reference frequency RF is equal to or greater than the intensity threshold THFS is set as the appropriate defocus amount ADF. The reference frequency RF is, for example, the high-frequency cutoff frequency of the bandpass filter used for filtering the first calculation data DC1 and the second calculation data DC2. The adoption condition 126 is an example of a "condition" relating to the technology of this disclosure. The intensity threshold THFS is an example of a "third threshold range" relating to the technology of this disclosure. Furthermore, being equal to or greater than the intensity threshold THFS is an example of being "within the third threshold range" relating to the technology of this disclosure.

[0137] As an example, as shown by the solid line in Figure 32, the adoption determination unit 72 determines that the defocus amount DF calculated when the intensity FS at the reference frequency RF is equal to or greater than the intensity threshold THFS will be adopted as the suitable defocus amount ADF. Conversely, as shown by the dashed line, the adoption determination unit 72 determines that the defocus amount DF calculated when the intensity FS at the reference frequency RF is less than the intensity threshold THFS will not be adopted as the suitable defocus amount ADF.

[0138] Thus, in the fifth embodiment, the frequency intensity calculation unit 125 determines the intensity FS of the frequency components in the focus adjustment region 50. The adoption condition 126 is that the defocus amount DF calculated when the intensity FS at the reference frequency RF is equal to or greater than the intensity threshold THFS is set as the appropriate defocus amount ADF. Generally, as the focus lens 14 approaches the focus position, the high-frequency intensity FS increases, and the calculation accuracy of the defocus amount DF also increases. Therefore, by setting the constraint that the intensity FS at the reference frequency RF is equal to or greater than the intensity threshold THFS, the subject distance can be detected using the defocus amount DF, which has relatively high calculation accuracy. Thus, even in the fifth embodiment, it is possible to suppress the decrease in the accuracy of subject distance detection compared to the case where all of the defocus amount DF calculated in the pixel summing mode is used to detect the subject distance without any constraints.

[0139] As with the fourth embodiment described above, the setting area is not limited to the example focus adjustment area 50. It may be the entire imaging surface 42. Also, the focus adjustment area data 121 may be a collection of calculation signals 43P output from the phase difference detection pixels 41P present in the focus adjustment area 50.

[0140] In the first embodiment described above, a second switching condition 662 was given as an example in which the defocus amount DF is less than or equal to the first threshold amount THA1, but it is not limited to this. For example, as shown in Figure 33, the second switching condition 1302 may be such that the number of consecutive times the defocus amount DF has been calculated is greater than or equal to the third threshold count THT3. The third threshold count THT3 is, for example, 4 times.

[0141] The number of pixels to which the calculation signal 43P is added in the pixel addition process is not limited to the four shown in the example. It may be six or eight. If the defocus amount DF cannot be calculated after performing pixel addition for four pixels, the system may be configured to switch to pixel addition for six or eight pixels.

[0142] In the embodiments described above, the example of switching from a distant view to a close-up view was used, but the invention is not limited to this. Conversely, the technology of this disclosure can also be applied when switching from a close-up view to a distant view. Furthermore, in the embodiments described above, the example of video recording was used, but the invention is not limited to this. The technology of this disclosure may also be applied when taking still images or displaying live view images.

[0143] The imaging device relating to the technology disclosed herein is not limited to the example mirrorless interchangeable-lens digital camera, but may also be a compact digital camera, video camera, surveillance camera, smartphone, or tablet device.

[0144] In each of the above embodiments, for example, the hardware structure of the Processing Unit that performs various processes such as the image processing unit 27, display control unit 30, instruction reception unit 32, focus control unit 68, focus calculation unit 70, mode switching setting unit 71, adoption / rejection determination unit 72, distance detection unit 73, focus lens drive control unit 74, mode switching unit 90, pixel addition unit 91, correlation calculation unit 92, defocus amount calculation unit 93, contrast value calculation unit 120, and frequency intensity calculation unit 125 can be any of the following types of processors. The types of processors include a CPU 56, which is a general-purpose processor that executes software (operation program 65) and functions as various processing units, as well as a Programmable Logic Device (PLD), which is a processor whose circuit configuration can be changed after manufacturing, such as an FPGA (Field Programmable Gate Array), and / or a dedicated electrical circuit, which is a processor with a circuit configuration specifically designed to perform a particular process, such as an ASIC (Application Specific Integrated Circuit).

[0145] A single processing unit may consist of one of these various processors, or it may consist of a combination of two or more processors of the same or different types (for example, a combination of multiple FPGAs, and / or a combination of a CPU and an FPGA). Alternatively, multiple processing units may be composed of a single processor.

[0146] Examples of configuring multiple processing units with a single processor include, firstly, a configuration where one or more CPUs and software combine to form a single processor, which then functions as multiple processing units, as exemplified by client and server computers. Secondly, a configuration using a processor that realizes the functions of the entire system, including multiple processing units, on a single IC (Integrated Circuit) chip, as exemplified by System-on-a-Chip (SoC). Thus, various processing units are configured, in terms of hardware structure, using one or more of the above-mentioned processors.

[0147] Furthermore, the hardware structure of these various processors can more specifically utilize electrical circuits (Circuitry) that combine circuit elements such as semiconductor elements.

[0148] From the above description, the technology described in the following supplementary information can be understood.

[0149] [Additional note 1] Equipped with a processor, The aforementioned processor, Obtain a focus evaluation value corresponding to the sum of the pixel values ​​of multiple phase difference detection pixels. Focus control is performed using the focus evaluation value that satisfies the pre-set conditions. Focusing control device. [Additional note 2] The aforementioned processor, Based on the focus evaluation value that satisfies the above conditions, the distance to the subject is detected. The focusing control device according to Appendix 1, which performs the focusing control according to the distance. [Additional note 3] The focusing control device according to Appendix 1 or Appendix 2, wherein the condition is that the focusing evaluation value relating to the difference between the current position of the focusing lens and the focused position of the focusing lens is within a first threshold range. [Additional note 4] The aforementioned processor, The focusing control device according to Appendix 3, which sets the speed of the focusing lens to a speed that can secure a preset number of the aforementioned focusing evaluation values. [Additional note 5] The aforementioned processor, A focusing control device according to any one of the appendix 1 to 4, which switches between a pixel addition mode in which the aforementioned pixel values ​​are added and a non-pixel addition mode in which the aforementioned pixel values ​​are not added. [Additional note 6] The focusing control device according to Appendix 5, wherein the focusing evaluation value that satisfies the above conditions is the focusing evaluation value obtained after the first threshold number of cycles following a switch from the non-pixel addition mode to the pixel addition mode. [Additional note 7] The aforementioned processor, The focusing control device according to Appendix 5 or Appendix 6, wherein the focusing evaluation value acquired from the time set to elapse after switching from the non-pixel addition mode to the pixel addition mode is not considered the focusing evaluation value that satisfies the conditions. [Additional note 8] The aforementioned processor, The contrast value in a set region of the imaging surface of the image sensor on which the phase difference detection pixels are arranged is determined. The focusing control device according to any one of Appendix 1, Appendix 2, or Appendix 5, wherein the focusing evaluation value that satisfies the above conditions is the focusing evaluation value calculated when the contrast value is within the second threshold range. [Additional note 9] The aforementioned processor, The intensity of frequency components in a set region of the imaging surface of the image sensor on which the phase difference detection pixels are arranged is determined. The focusing control device according to any one of Appendix 1, Appendix 2, or Appendix 5, wherein the focusing evaluation value that satisfies the above conditions is the focusing evaluation value calculated when the intensity at the reference frequency is within the third threshold range. [Additional Note 10] The aforementioned processor, If there is no focus evaluation value that satisfies the above conditions, the focus control device described in any one of the appendix items 1 to 9 does not perform the focus control using the focus evaluation value. [Additional Note 11] The aforementioned processor, A focusing control device according to any one of the appendix 1 to 10, which adds the pixel values ​​of a plurality of phase difference detection pixels that are connected in the phase difference detection direction. [Additional Note 12] The aforementioned processor, The system switches between a pixel addition mode in which the aforementioned pixel values ​​are added and a non-pixel addition mode in which the aforementioned pixel values ​​are not added. When the preset first switching condition is met in the non-pixel addition mode, the system switches to the pixel addition mode. The focusing control device according to any one of the appendix items 1 to 11, which switches to the non-pixel addition mode when a preset second switching condition is met in the pixel addition mode. [Additional Note 13] The focusing control device according to Appendix 12, wherein the first switching condition is that the number of consecutive times the focusing evaluation value cannot be calculated in the non-pixel summing mode is equal to or greater than the second threshold number of times. [Additional Note 14] The focusing control device according to appendix 12 or appendix 13, wherein the second switching condition is that the focusing evaluation value is within the fourth threshold range. [Additional Note 15] The focusing control device according to appendix 12 or appendix 13, wherein the second switching condition is that the number of consecutive times the focusing evaluation value is calculated in the pixel addition mode is equal to or greater than the third threshold number. [Additional Note 16] An imaging device equipped with a focusing control device as described in any one of the appendices 1 to 15.

[0150] Note that the first threshold count THT1 is an example of the "second threshold count" in Appendix 13. The first threshold amount THA1 is an example of the "fourth threshold range" in Appendix 14. An amount less than or equal to the first threshold amount THA1 is an example of being "within the fourth threshold range" in Appendix 14. The third threshold count THT3 is an example of the "third threshold count" in Appendix 15.

[0151] The technology of this disclosure can be appropriately combined with the various embodiments and / or variations described above. Furthermore, it is understood that various configurations can be adopted without departing from the spirit of the invention, and the invention is not limited to the embodiments described above. In addition, the technology of this disclosure extends not only to programs, but also to storage media for non-temporarily storing programs, and to computer program products containing programs.

[0152] The descriptions and illustrations presented above are detailed explanations of the technical aspects of this disclosure and are merely examples of the technical aspects. For example, the above descriptions of the structure, function, operation, and effect are examples of the structure, function, operation, and effect of the technical aspects of this disclosure. Therefore, it goes without saying that you may delete unnecessary parts, add new elements, or replace elements in the descriptions and illustrations presented above, as long as you do not deviate from the essence of the technical aspects of this disclosure. Furthermore, in order to avoid confusion and facilitate understanding of the technical aspects of this disclosure, explanations of common technical knowledge and the like that do not require special explanation to enable the implementation of the technical aspects of this disclosure have been omitted from the descriptions and illustrations presented above.

[0153] In this specification, "A and / or B" is synonymous with "at least one of A and B." That is, "A and / or B" means that it may be A alone, or B alone, or a combination of A and B. Furthermore, in this specification, the same concept as "A and / or B" applies when expressing three or more things linked by "and / or."

[0154] All documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference. [Explanation of Symbols]

[0155] 10 Imaging device 11. Imaging optical system 12 Image sensor 13 Objective lens 14 Focus Lens 15 zoom lens 16 aperture 17 Focus lens drive mechanism 18 Zoom lens drive mechanism 19 Aperture drive mechanism 20 Control Unit 21 Control section 22 Image sensor driver 23 Shutter 24. Shutter drive mechanism 25 Image Input Controller 26 Image memory 27 Image Processing Unit Bus lines 28 and 58 29 VRAM 30 Display Control Unit 31 Media Controller 32 Instruction Reception Department 33. Viewfinder Monitor 34 Rear monitor 35 memory cards 36 Touch Panel 40 Photoelectric conversion unit 41 pixels 41N Standard Pixels 41P Pixel for phase difference detection 42 Imaging surface 43 Image signal 43N signal for image generation 43P Calculation Signal 45 Microlenses 46 Color Filters 47 Photoelectric conversion element 49 Light-shielding material 50. Area for calculating the amount of defocus (focus adjustment area) 55 storage 56 CPU 57 memory 65 Operating Program 67, 110, 122, 126 Recruitment conditions 68 Focusing Control Unit 70 Focus calculation section 71 Mode switching setting section 72 Adoptability Judgment Department 73 Distance detection unit 74 Focus lens drive control unit 80 Drive amount 81 Focus calculation result 82 Configuration Information 83 Recruitment decision result 84 Detection Results 90 Mode switching section 91 Pixel Addition Unit 92 Correlation Calculation Unit 93 Defocus Amount Calculation Unit 100 graphs 102 Mountain 103 People 120 Contrast Value Calculation Unit 121 Focus adjustment area data 125 Frequency Intensity Calculation Unit 411P First phase difference detection pixel 412P Second phase-difference detection pixel 431P 1st calculation signal 432P Second calculation signal 441P First calculation signal after addition 442P Second calculation signal after addition 661 First switching condition 662, 1302 Second switching conditions α phase difference ADF (Automatic Definition Function) Compatible Defocus Amount CC Correlation Curve CV contrast value DC calculation data DC1 Data for First Calculation DC2 Second Calculation Data DCA data for post-addition calculations DCA1 Data for the first calculation after addition DCA2 Data for the second calculation after addition DF Defocus Amount FS frequency component intensity NS threshold count OA optical axis PD, PE, PF, PG, PH, PI, PJ Estimated focus position RF reference frequency ST100, ST110, ST120, ST130, ST140, ST150, ST160, ST170 Step TA, TB, TC, TD, TE, TF, TG, TH, TI, TJ Time THA1 First Threshold THA2 Second Threshold THCV contrast threshold THFS intensity threshold THT1 First Threshold Count THT2 Second Threshold Count THT3 Third Threshold Count

Claims

1. Equipped with a processor, The aforementioned processor, Obtain a focus evaluation value corresponding to the sum of the pixel values ​​of multiple phase difference detection pixels. Focus control is performed using the focus evaluation value that satisfies the pre-set conditions. Focusing control device.

2. The aforementioned processor, Based on the focus evaluation value that satisfies the above conditions, the distance to the subject is detected. The focusing control device according to claim 1, which performs the focusing control according to the distance.

3. The focusing control device according to claim 1, wherein the condition is that the focusing evaluation value relating to the difference between the current position of the focusing lens and the focused position of the focusing lens is within a first threshold range.

4. The aforementioned processor, The focusing control device according to claim 3, which sets the speed of the focusing lens to a speed that can secure a preset number of the aforementioned focusing evaluation values.

5. The aforementioned processor, The focusing control device according to claim 1, which switches between a pixel addition mode in which the pixel values ​​are added and a non-pixel addition mode in which the pixel values ​​are not added.

6. The focusing control device according to claim 5, wherein the focusing evaluation value that satisfies the above conditions is the focusing evaluation value obtained after the first threshold count following a switch from the non-pixel addition mode to the pixel addition mode.

7. The aforementioned processor, The focusing control device according to claim 5, wherein the focusing evaluation value obtained from switching from the non-pixel addition mode to the pixel addition mode until the set time has elapsed is not the focusing evaluation value that satisfies the conditions.

8. The aforementioned processor, The contrast value in a set region of the imaging surface of the image sensor on which the phase difference detection pixels are arranged is determined. The focusing control device according to claim 1, wherein the focusing evaluation value that satisfies the above conditions is the focusing evaluation value calculated when the contrast value is within the second threshold range.

9. The aforementioned processor, The intensity of frequency components in a set region of the imaging surface of the image sensor on which the phase difference detection pixels are arranged is determined. The focusing control device according to claim 1, wherein the focusing evaluation value that satisfies the above conditions is the focusing evaluation value calculated when the intensity at the reference frequency is within the third threshold range.

10. The aforementioned processor, The focusing control device according to claim 1, wherein if there is no focusing evaluation value that satisfies the above conditions, the focusing control using the focusing evaluation value is not performed.

11. The aforementioned processor, The focusing control device according to claim 1, which adds the pixel values ​​of a plurality of phase difference detection pixels that are aligned in the phase difference detection direction.

12. To obtain a focus evaluation value corresponding to the sum of the pixel values ​​of multiple phase difference detection pixels, and, Focus control is performed using the focus evaluation value that satisfies the pre-set conditions. A method for operating a focus control device, including the operation of a focus control device.

13. To obtain a focus evaluation value corresponding to the sum of the pixel values ​​of multiple phase difference detection pixels, and, Focus control is performed using the focus evaluation value that satisfies the pre-set conditions. An operating program for a focus control device that causes a computer to perform a process including the following.

14. An imaging device comprising the focusing control device described in claim 1.

Images