Imaging apparatus

Abstract

To improve focusing accuracy on a main subject.SOLUTION: An imaging apparatus comprises: a distance measuring device including a light emitting unit that emits light, a light receiving unit that receives light obtained by reflecting the light emitted from the light emitting unit by an object, and a generation unit that generates information relating to a distance to the object on the basis of a light reception result of the light receiving unit; an imaging element including pixels that receive the light passing through an optical system including a focus lens and output information used for focus detection; and a control unit that controls a position of the focus lens on the basis of the information relating to the distance to the object and the information used for the focus detection.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] It relates to an imaging device.

Background Art

[0002] An imaging device has been proposed that aims to improve focusing accuracy and shorten the focusing time by using a distance measuring device that measures the distance to a subject (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] According to a first aspect of the disclosure, the imaging device includes a light emitting unit that emits light, a light receiving unit that receives light reflected by an object from the light emitted by the light emitting unit, and a generation unit that generates information regarding the distance to the object based on the light receiving result of the light receiving unit. The imaging device further includes an imaging element including pixels that receive light that has passed through an optical system including a focus lens and outputs information used for focus detection, and a control unit that controls the position of the focus lens based on the information regarding the distance to the object and the information used for focus detection.

[0005] According to a second aspect of the disclosure, the imaging device includes an acquisition unit that acquires information regarding the distance to the object from a distance measuring device including a light emitting unit that emits light, a light receiving unit that receives light reflected by the object from the light emitted by the light emitting unit, and a generation unit that generates information regarding the distance to the object based on the light receiving result of the light receiving unit. The imaging device further includes an imaging element including pixels that receive light that has passed through an optical system including a focus lens and outputs information used for focus detection, and a control unit that controls the position of the focus lens based on the information regarding the distance to the object and the information used for focus detection.

[0006] Note that the configuration of the embodiments described below may be improved as appropriate, and at least a part thereof may be replaced with other components. Furthermore, constituent elements with no particular limitation on their arrangement are not limited to the arrangements disclosed in the embodiments, and can be arranged at positions where their functions can be achieved.

Brief Description of the Drawings

[0007]

Figure 1

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Best Mode for Carrying Out the Invention

[0008] 《First Embodiment》 Hereinafter, a digital camera 1 (hereinafter referred to as the camera 1), which is an example of an imaging device according to the first embodiment, will be described with reference to FIGS. 1 to 6.

[0009] FIG. 1 is a diagram showing the configuration of the camera 1 according to the first embodiment. The camera 1 includes a camera body 2, an interchangeable lens 3, and a distance measuring device 50. In the present embodiment, the camera 1 is an interchangeable lens camera, but the camera 1 may be configured as an integrated lens camera instead of an interchangeable lens camera.

[0010] (Distance Measuring Device 50) The distance measuring device 50 is, for example, a distance measuring device using LiDAR (Light Detection And Ranging) that irradiates laser light and measures the distance to an object, the shape and size of the object, etc. based on the information of the reflected light. The distance measuring device 50 includes a light emitting unit 501, a light receiving unit 502, a control unit 503, and a distance measuring device side connector unit 504.

[0011] The light emitting unit 501 is, for example, a vertical cavity surface emitting laser (VCSEL: Vertical-Cavity Surface-Emitting Laser), and emits laser light such as near infrared light toward the target area. Here, the target area is an area corresponding to the imaging range of the distance measuring device 50, and is an area corresponding to the angle of view of the distance measuring device 50.

[0012] The light receiving unit 502 detects light from the target area. Specifically, the light receiving unit 502 is an imaging element that detects light reflected by an object (target object) in the target area from the light emitted from the light emitting unit 501. The light receiving unit 502 includes a light receiving pixel unit 502a and a light receiving pixel control unit 502b. In the following description, the light reflected by an object in the target area may be referred to as reflected light.

[0013] The light-receiving pixel section 502a has a plurality of pixels each having a photoelectric conversion section. The plurality of pixels are arranged two-dimensionally (in the row direction and the column direction). The photoelectric conversion section is constituted by a photodiode (PD) or a SPAD (Single Photon Avalanche Diode) having higher sensitivity than the photodiode. In the present embodiment, the description will proceed on the assumption that the photoelectric conversion section is a photodiode.

[0014] The photoelectric conversion section of each pixel of the light-receiving pixel section 502a receives the reflected light of the light emitted by the light-emitting section 501 and accumulates charges corresponding to the amount of the reflected light. More specifically, the photoelectric conversion section of each pixel accumulates charges corresponding to the amount of the reflected light received within a predetermined exposure time. Then, the light-receiving pixel section 502a outputs, from each pixel to the control section 503, a signal corresponding to the charges accumulated in the photoelectric conversion section in accordance with a control signal from the light-receiving pixel control section 502b.

[0015] The light-receiving pixel control section 502b causes each pixel of the light-receiving pixel section 502a to accumulate charges and causes each pixel to output a signal based on the accumulated charges, based on an instruction signal from the control section 503.

[0016] The control section 503 calculates the time Δt from when the light-emitting section 501 emits light until the reflected light of the emitted light is received by the light-receiving section 502, using the signals output from the respective pixels of the light-receiving pixel section 502a, and calculates the distance to each object in the target area based on the time Δt and the speed of light.

[0017] Specifically, the control unit 503 includes a generation unit 505 that calculates the distance to an object for each pixel of the light-receiving pixel unit 502a, and generates an image with the distance (the value corresponding thereto) as the pixel value and an image with information based on the intensity of the reflected light as the pixel value (hereinafter, these are collectively referred to as the distance image). Further, the generation unit 505 generates information regarding the size of each object existing within the target region (within the distance image) based on the distance image. Here, the size of each object means the length in each of the X direction and the Y direction when the photographer takes a horizontally long image with the optical axis OA1 horizontal, with the direction from the subject toward the camera body 2 side at the camera position (hereinafter referred to as the normal position) as the +Z direction, the direction toward the right side when viewed from the camera body 2 side at the normal position as the +X direction, and the direction upward at the normal position as the +Y direction (see FIG. 1). In the present embodiment, the information regarding the size of each object is assumed to include information regarding the position of each object within the distance image in addition to the size of each object.

[0018] The control unit 503 transmits the generated distance image and the information regarding the size of each object to the body control unit 21 via the distance measuring device side connector unit 504 and the body side connector unit 26 described later. Note that the control unit 503 may generate data capable of calculating the distance to the object (for example, data including the time Δt at each pixel) instead of the distance image and output it to the body control unit 21.

[0019] (Interchangeable lens 3) The interchangeable lens 3 includes a lens side mount portion 301, a photographing optical system (imaging optical system) 31, a lens control unit 32, and a lens memory 33. The lens side mount portion 301 includes a lens side connection portion 302. The lens side connection portion 302 has a plurality of terminals such as a terminal for a clock signal, a terminal for a data signal, and a terminal for power supply. The interchangeable lens 3 is detachably attached to the camera body 2 by the lens side mount portion 301 and the body side mount portion 201 described later.

[0020] The imaging optical system 31 includes a plurality of lenses including a zoom lens (variable magnification lens) 31a that changes the focal length and a focus lens (focus adjustment lens) 31b, and a diaphragm 31c, and forms a subject image on the imaging surface 22a of the imaging device 22.

[0021] The lens control unit 32 is composed of a processor such as a CPU, FPGA, or ASIC, and a memory such as a ROM or RAM, and controls each part of the interchangeable lens 3 based on a control program. The lens control unit 32 controls the position of the zoom lens 31a, the position of the focus lens 31b, and the drive of the diaphragm 31c based on a signal output from the body control unit 21 of the camera body 2. When a signal indicating the moving direction and moving amount of the focus lens 31b, etc. is input from the body control unit 21 to the lens control unit 32, the focus lens 31b is moved back and forth in the direction of the optical axis OA1 based on that signal to adjust the focus position of the imaging optical system 31. Further, the lens control unit 32 controls the position of the zoom lens 31a and the aperture diameter of the diaphragm 31c based on a signal output from the body control unit 21 of the camera body 2.

[0022] The lens memory 33 is composed of, for example, a non-volatile storage medium or the like. Information related to the interchangeable lens 3 is stored (recorded) as lens information in the lens memory 33. The lens information includes data regarding the optical characteristics (exit pupil distance and F-number) of the imaging optical system 31, data regarding the shortest shooting distance of the imaging optical system 31, and the like. Note that the lens information varies depending on the type of the interchangeable lens 3. Also, the lens information may be stored in the memory inside the lens control unit 32. Further, the lens information may be stored in the body memory 23 of the camera body 2 described later. In this case, the body memory 23 stores the lens information of a plurality of interchangeable lenses 3.

[0023] The reading of data from the lens memory 33 is controlled by the lens control unit 32. When the interchangeable lens 3 is attached to the camera body 2, the lens control unit 32 transmits lens information to the body control unit 21 via the terminals of the lens-side connection unit 302 and the body-side connection unit 202. Also, the lens control unit 32 transmits to the body control unit 21 information such as the position information (focal length information) of the controlled zoom lens 31a, the position information of the controlled focus lens 31b, and the aperture value (F value) information of the controlled imaging optical system 31.

[0024] The lens control unit 32 performs bidirectional information transmission and reception communication between the camera body 2 and the interchangeable lens 3 via the terminals of the lens-side connection unit 302 and the body-side connection unit 202. When the zoom lens 31a moves and the focal length of the imaging optical system 31 changes, the lens control unit 32 may transmit information on the focal length of the imaging optical system 31 and information on the aperture value of the imaging optical system 31 to the body control unit 21, or may periodically transmit information on the focal length of the imaging optical system 31 and information on the aperture value of the imaging optical system 31 to the body control unit 21.

[0025] (Camera body 2) The camera body 2 includes a body-side mount portion 201, an imaging element 22, a body memory 23, a display unit 24, an operation unit 25, a body-side connector portion 26, and a body control unit 21.

[0026] The body-side mount portion 201 includes a body-side connection unit 202. The body-side connection unit 202 has a plurality of terminals such as a terminal for a clock signal, a terminal for a data signal, and a terminal for power supply.

[0027] When the interchangeable lens 3 is attached to the camera body 2, the terminals provided on the body-side connection unit 202 and the terminals provided on the lens-side connection unit 302 are electrically connected. Thereby, power supply from the camera body 2 to the interchangeable lens 3 and communication between the camera body 2 and the interchangeable lens 3 become possible.

[0028] The imaging device 22 is a CMOS image sensor or a CCD image sensor. The imaging device 22 images the subject image formed by the photographing optical system 31. The imaging device 22 includes a pixel unit 221 in which a plurality of pixels having a photoelectric conversion unit are arranged two-dimensionally (in the row direction and the column direction), and a control unit 222 that controls the pixel unit 221. The photoelectric conversion unit is composed of a photodiode.

[0029] The pixel unit 221 has imaging pixels that photoelectrically convert the received light by the photoelectric conversion unit and output signals used for image generation, and focus detection pixels that photoelectrically convert the received light by the photoelectric conversion unit and output signals used for focus detection.

[0030] Based on the instruction signal from the body control unit 21, the control unit 222 causes the focus detection pixels to output signals used for focus detection. Further, based on the instruction signal from the body control unit 21, the control unit 222 causes the imaging pixels to output signals used for image generation.

[0031] The body memory 23 is composed of, for example, a non-volatile storage medium or the like. Image data, control programs, etc. are recorded in the body memory 23. Writing data to the body memory 23 and reading data from the body memory 23 are controlled by the body control unit 21. The display unit 24 displays an image based on the image data, an image indicating a focus detection area (AF area) such as an AF frame, information related to photographing such as shutter speed and F value, and a menu screen or the like.

[0032] The operation unit 25 includes various setting switches such as a release button, a power switch, and a switch for switching various modes, and outputs an operation signal corresponding to each operation to the body control unit 21.

[0033] The body control unit 21 is composed of a processor such as a CPU, FPGA, or ASIC, and a memory such as a ROM and a RAM, and controls each part of the camera 1 based on a control program.

[0034] Here, for example, when the swimmer is photographed as the main subject by the camera 1, during autofocus, the camera may focus on the water splashes generated around the swimmer instead of the swimmer who is the main subject, or the driving of the focus lens 31b may become unstable due to the water splashes generated around the swimmer.

[0035] Therefore, in the first embodiment, the body control unit 21 determines whether to drive the focus lens 31b based on the information on the size of each object based on the distance image generated by the control unit 503 of the distance measuring device 50 and the defocus amount calculated based on the signal output from the focus detection pixels, thereby improving the focusing accuracy on the main subject and stabilizing the driving of the imaging optical system 31.

[0036] FIG. 2 is a flowchart showing an example of the process executed by the body control unit 21 of the camera body 2, and FIG. 3 is a flowchart showing an example of the process executed by the control unit 503 of the distance measuring device 50.

[0037] The process of FIG. 2 starts when the power of the camera body 2 is turned on. When the process of FIG. 2 starts, the body control unit 21 waits until an AF instruction is received (the release button is half-pressed) (step S11 / NO).

[0038] When the body control unit 21 receives an AF instruction (step S11 / YES), it outputs a distance measurement process start instruction for instructing the start of the distance measurement process to the control unit 503 of the distance measuring device 50 (step S13).

[0039] On the other hand, the control unit 503 of the distance measuring device 50 waits until a distance measurement process start instruction is received (FIG. 3: step S101 / NO). When the control unit 503 receives a distance measurement process start instruction (step S101 / YES), it starts an exposure process (step S103). The exposure process is a process of causing the light emitting unit 501 to emit light and accumulating charges in the photoelectric conversion units of the respective pixels of the light receiving pixel unit 502a.

[0040] When the exposure process ends, the control unit 503 causes the light-receiving pixel unit 502a to output a signal corresponding to the charge accumulated in each pixel of the light-receiving pixel unit 502a (step S105). The control unit 503 (generation unit 505) generates a distance image based on the signal output from the light-receiving pixel unit 502a. Further, the control unit 503 (generation unit 505) generates information regarding the size of each object included in the distance image based on the generated distance image (step S107).

[0041] The control unit 503 transfers the generated distance image and the information regarding the size of each object to the body control unit 21 (step S109).

[0042] The control unit 503 determines whether it has received a ranging process end instruction for instructing the end of the ranging process from the body control unit 21 (step S111). If the ranging process end instruction has not been received (step S111 / NO), the process returns to step S103. The processes of steps S103 to S109 are repeatedly executed until the ranging process end instruction is received. On the other hand, when the ranging process end instruction is received (step S111 / YES), the control unit 503 ends the process of FIG. 3.

[0043] On the other hand, after transmitting the ranging process start instruction (FIG. 2: step S13), the body control unit 21 receives a distance image and information regarding the size of each object in the distance image from the ranging device 50 (step S15). Further, in parallel with the process of step S15, the body control unit 21 executes a focus detection process (step S17). Specifically, the body control unit 21 calculates the deviation amount between the image plane of the imaging optical system 31 and the imaging plane 22a of the imaging device 22 using the signal from the focus detection pixels of the imaging device 22, and converts the calculated deviation amount into a defocus amount.

[0044] Next, the body control unit 21 determines whether or not the defocus amount calculated in step S17 is within the allowable value range (step S19). When the defocus amount is within the allowable value range (step S19 / YES), the body control unit 21 determines that it is in focus and proceeds to step S27. On the other hand, when the defocus amount is outside the allowable value range (step S19 / NO), the body control unit 21 determines that it is out of focus and determines whether or not the size of the object existing in the area where the defocus amount was acquired is less than a predetermined value (step S21).

[0045] Here, for example, when photographing a swimmer SWM1 in a swimming competition as shown in FIG. 4, if the defocus amount calculated for the water splash SPL1 around the swimmer is used to calculate the target position of the focus lens 31b, the swimmer SWM1 may be out of focus depending on the settings of the camera 1 (for example, the aperture value). Therefore, in the first embodiment, the body control unit 21 determines whether or not there is a water splash in the area where the defocus amount used to calculate the target position of the focus lens 31b was acquired, based on the information regarding the size of each object received from the distance measuring device 50. In other words, the body control unit 21 determines whether or not the object existing in the area where the defocus amount used to calculate the target position of the focus lens 31b was acquired is an object other than the main subject (swimmer SWM1).

[0046] Specifically, in the distance image, the body control unit 21 determines whether or not the size of the object existing in the area corresponding to the area where the defocus amount used to calculate the target position of the focus lens 31b was acquired is less than the threshold value (predetermined value). For example, it is determined whether or not both the horizontal dimension and the vertical dimension of the object are less than the threshold value (for example, 5 mm). Note that it may be determined whether or not both the horizontal dimension and the vertical dimension of the object are equal to or greater than a threshold value (for example, 5 cm) at which it can be determined that the object is not a water splash. Hereinafter, it will be described as determining whether or not the size of the object is less than a predetermined value.

[0047] Returning to FIG. 2, when the size of the object is less than a predetermined value (step S21 / YES), it is highly likely that the defocus amount is the defocus amount calculated for the water splash. In this case, the body control unit 21 drives the focus lens 31b to the target position of the focus lens 31b based on the focus detection result used for the previous drive of the focus lens 31b (step S23). On the other hand, when the size of the object is greater than or equal to the predetermined value (step S21 / NO), since it is highly likely that the defocus amount is the defocus amount calculated for the swimmer SWM1, the focus lens 31b is driven to the target position of the focus lens 31b calculated based on the focus detection result of step S19 (step S25).

[0048] When the determination in step S19 is YES, after the end of step S23 or after the end of step S25, the body control unit 21 determines whether the AF instruction has been canceled (step S27). For example, the body control unit 21 determines that the AF instruction has been canceled when the half-press of the release button is released, or when the release button is fully pressed and a shooting instruction is received. If the AF instruction has not been canceled (step S27 / NO), the process returns to steps S15 and S17. If the AF instruction has been canceled (step S27 / YES), a ranging process end instruction for instructing the end of the ranging process is transmitted to the ranging device 50 (step S29), and the process of FIG. 2 ends.

[0049] FIG. 5 is a sequence diagram for explaining the processes of FIGS. 2 and 3. FIG. 5 shows the processes executed by the ranging device 50 and the camera body 2 after the ranging process start instruction is transmitted to the ranging device 50, and the target position of the focus lens 31b.

[0050] When the distance measurement device 50 receives an instruction to start the distance measurement process, it starts the distance measurement process. The distance measurement process (described as "distance measurement" in FIG. 5) includes a process of accumulating charges in the photoelectric conversion units of the respective pixels of the light receiving pixel unit 502a (described as "exposure" in FIG. 5), and a process of outputting a signal corresponding to the charges accumulated from the respective pixels of the light receiving pixel unit 502a (described as "output" in FIG. 5). In FIG. 5, "transfer" represents a process of transferring the distance image and information regarding the size of each object to the body control unit 21.

[0051] On the other hand, in the camera body 2, after the body control unit 21 outputs an instruction to start the distance measurement process, it starts a process of accumulating charges in the photoelectric conversion unit of the focus detection pixel of the imaging device 22 (described as "accumulation" in FIG. 5). Then, the body control unit 21 executes a focus detection process based on the signal corresponding to the charges accumulated in the photoelectric conversion unit of the focus detection pixel, and calculates the target position (target lens position) of the focus lens 31b. In FIG. 5, the process of executing the focus detection process based on the signal from the focus detection pixel and calculating the target position of the focus lens 31b is described as "AF operation".

[0052] Here, for example, assuming that the target position of the focus lens 31b calculated as a result of the focus detection process based on the signal corresponding to the charges accumulated in accumulation 4 is position TP1. At this time, if the size of the object existing in the region where the defocus amount used for calculating the target position TP1, which is obtained from the information regarding the size of each object transferred in transfer 4, is less than a predetermined value, the body control unit 21 drives the focus lens 31b to the target position TP2 calculated in the previous AF operation 3 instead of the target position TP1.

[0053] FIG. 6 is a diagram illustrating the behavior of the focus lens 31b when the position of the focus lens 31b is controlled by the method according to the first embodiment, and when the position of the focus lens 31b is controlled based on the defocus amount calculated in the focus detection process regardless of the size of the object existing in the region where the defocus amount used for calculating the target position of the focus lens 31b is obtained (comparative example). In FIG. 6, the horizontal axis represents time, and the vertical axis represents the target position of the focus lens 31b.

[0054] In FIG. 6, for example, it is assumed that the swimming competition shown in FIG. 4 is being photographed, and the behavior of the swimmer SWM1, which is the main subject, is indicated by a thin line. In FIG. 6, the black circles indicate the target positions of the focus lens 31b calculated based on the defocus amount calculated for the swimmer SWM1, and the white circles indicate the target positions of the focus lens 31b calculated based on the defocus amount calculated for the water splash SPL1. In the example of FIG. 6, the defocus amount is calculated substantially alternately for the swimmer SWM1 and the water splash SPL1.

[0055] In the comparative example, regardless of the size of the object existing in the region where the defocus amount used for calculating the target position of the focus lens 31b is obtained, the target position of the focus lens 31b is calculated based on the calculated defocus amount, and the position of the focus lens 31b is controlled. Therefore, as shown by the broken line, the driving of the focus lens 31b becomes unstable. On the other hand, in the first embodiment, when the object existing in the region where the defocus amount used for calculating the target position of the focus lens 31b is obtained is smaller than a predetermined value, that is, when the object is a water splash, the focus lens 31b is not driven to the target position of the focus lens 31b calculated based on the defocus amount. Therefore, as shown by the thick line, the driving of the focus lens 31b becomes stable.

[0056] As described in detail above, the camera 1 according to the first embodiment includes a light emitting unit 501 that emits light, a light receiving unit 502 that receives light reflected by an object from the light emitted by the light emitting unit 501, and a control unit 503 that generates a distance image (information regarding the distance to the object) based on the light receiving result of the light receiving unit 502. The camera 1 further includes an imaging device 22 that includes focus detection pixels that receive light that has passed through an imaging optical system 31 including a focus lens 31b and outputs information used for focus detection, information regarding the size of an object based on the distance image, and a body control unit 21 that controls the position of the focus lens 31b based on the information regarding the size of the object and the information used for focus detection (the defocus amount calculated using the signal output from the focus detection pixels). As a result, based on the size of an object existing in an area where the defocus amount used to calculate the target position of the focus lens 31b has been obtained, it is possible to determine whether the object is the main subject or an object other than the main subject. Thereby, it is possible to suppress focusing on an object other than the main subject, and the focusing accuracy on the main subject is improved.

[0057] Further, in the first embodiment, when the size of an object existing in an area where the defocus amount used to calculate the target position of the focus lens 31b has been obtained is equal to or greater than a predetermined value, the body control unit 21 controls the position of the focus lens 31b based on the information used for focus detection. As a result, since the position of the focus lens 31b is controlled when the object existing in the area where the defocus amount used to calculate the target position of the focus lens 31b has been obtained is the main subject, it is possible to suppress the drive of the focus lens 31b from becoming unstable.

[0058] Further, in the first embodiment, when the size of the object is less than the predetermined value, the body control unit 21 controls the position of the focus lens 31b based on the defocus amount before it is determined that the size of the object is less than the predetermined value. Thereby, it is possible to suppress the drive of the focus lens 31b from becoming unstable.

[0059] In addition, in the above-described first embodiment, when the size of the object existing in the region where the defocus amount used to calculate the target position of the focus lens 31b is obtained is less than a predetermined value, the body control unit 21 may control the position of the focus lens 31b based on the defocus amount calculated based on the signal output from the focus detection pixels provided in the region other than the region including the object. As a result, the position of the focus lens 31b can be controlled based on the defocus amount obtained in the region other than the region where the water splash exists, so that it is possible to prevent focusing on the water splash.

[0060] Also, in the above-described first embodiment, the size information of the object is obtained from the distance image based on the focus detection result. However, for example, a region where an object smaller than a predetermined value exists in the distance image may be obtained, and the body control unit 21 may execute the focus detection process using the region excluding the region as the focus detection region.

[0061] 《Second Embodiment》 In the second embodiment, photographing during rainfall or snowfall will be described. When photographing a person or the like as a main subject during snowfall or rainfall, during autofocus, the focus may be on snow or rain instead of the main subject, or the driving of the focus lens 31b may become unstable due to snow or rain. Therefore, in the second embodiment, the body control unit 21 determines whether rain or snow is falling during photographing, and controls the driving of the focus lens 31b according to the determination result. Since the configuration of the camera 1 is the same as that of the first embodiment, detailed description thereof will be omitted.

[0062] FIG. 7 is a flowchart showing an example of the process executed by the body control unit 21 in the second embodiment. Since the process executed by the control unit 503 of the distance measuring device 50 is the same as that of the first embodiment, detailed description thereof will be omitted. The process of FIG. 7 starts when the power of the camera body 2 is turned on.

[0063] When the process of FIG. 7 starts, the body control unit 21 sets the control defocus amount range to the first range (step S201). As shown in FIG. 8(A), the control defocus amount range is a range set outside the allowable value range of the defocus amount determined to be in focus. If the defocus amount calculated based on the signal from the focus detection pixels is within the control defocus amount range, the body control unit 21 drives the focus lens 31b based on the defocus amount, and if the defocus amount is outside the control defocus amount range, the body control unit 21 does not drive the focus lens 31b.

[0064] Next, the body control unit 21 waits until it receives an AF instruction (step S203 / NO). When the body control unit 21 receives an AF instruction (step S203 / YES), it outputs a distance measurement process start instruction to the control unit 503 of the distance measurement device 50 (step S205).

[0065] The body control unit 21 executes the processes of steps S207 to S215 and the processes of steps S223 to S231 in parallel.

[0066] When the body control unit 21 receives a distance image and information regarding the size of each object from the distance measurement device 50 (step S207), it determines whether or not the number of objects having a size less than a predetermined value is equal to or greater than a first threshold in the portion of the distance image corresponding to the focus detection region based on the information regarding the size of each object (step S209).

[0067] FIG. 8(B) is a diagram illustrating shooting during snowfall. In the second embodiment, as shown in FIG. 8(B), it is assumed that a plurality of focus detection regions AFA1 indicating regions where focus detection is performed are set. In this case, the body control unit 21 selects one focus detection region AFA1 for performing focus detection from the plurality of focus detection regions AFA1, and determines whether or not objects having a size equal to or less than a predetermined value are detected in a number equal to or greater than a first threshold in the selected focus detection region AFA1.

[0068] When the determination in step S209 in FIG. 7 is YES, the body control unit 21 determines whether or not a state where the number of objects having a size less than a predetermined value is equal to or greater than a first threshold has continued (persisted) for a certain period of time or more (step S211). Step S211 determines whether it is raining or snowing at the time of shooting. That is, if the time during which the number of objects having a size less than the predetermined value is detected to be equal to or greater than the first threshold continues for a certain period of time or more, it can be determined that it is raining or snowing. Note that in step S211, it may be determined whether or not the number of times the determination in step S209 was YES has continued for a certain number of times or more.

[0069] When the determination in step S211 is NO, the process returns to step S207. On the other hand, when the determination in step S211 is YES, the body control unit 21 sets the control defocus amount range to a second range (step S213). As shown in FIG. 8(C), the second range is a range narrower than the first range. Thereby, for example, even if a defocus amount is calculated for rain or snow located in front of the main subject, since the control defocus amount range is narrow, it is possible to suppress the driving of the focus lens 31b based on the defocus amount calculated for snow or the like. Also, since rain and snow exist on the front side of the main subject, the second range may be changed between the front side (defocus amount is positive) and the back side (defocus amount is negative) of the subject. In this case, the second range on the front side (defocus amount positive side) of the main subject may be set to be narrower than the second range on the back side (defocus amount negative side) of the main subject. Setting the control defocus amount range to the second range can also be said to be setting the shooting mode to the "rain / snow mode". After the end of step S213, the process returns to step S207.

[0070] By the way, when the number of objects having a size less than the predetermined value is less than the first threshold (step S209 / NO), the body control unit 21 sets the control defocus amount range to the first range (step S215), and returns to step S207. This is a process for returning the control defocus amount range to the first range, for example, when the rain or snow becomes light or stops.

[0071] In parallel with the processes of steps S207 to S215, the body control unit 21 executes focus detection processing (step S223). Next, the body control unit 21 determines whether the defocus amount calculated in step S223 is within the allowable value range (step S225).

[0072] When the defocus amount is within the allowable value range (step S225 / YES), the body control unit 21 determines that it is in focus, does not drive the focus lens 31b, and proceeds to step S229.

[0073] When the defocus amount is outside the allowable value range (step S225 / NO), the body control unit 21 determines whether the defocus amount is within the control defocus amount range (step S226). In the control defocus amount range, when the determination in step S211 is YES, that is, when it is determined that rain or snow is falling, a second range is set, and in other cases, a first range wider than the second range is set.

[0074] When the defocus amount is outside the control defocus amount range (step S226 / NO), the body control unit 21 does not drive the focus lens 31b and proceeds to step S229. When the defocus amount is within the control defocus amount range (step S226 / YES), the body control unit 21 drives the focus lens 31b to the target position calculated based on the defocus amount (step S227).

[0075] The body control unit 21 determines whether the AF instruction has been canceled (step S229). If the AF instruction has not been canceled (step S229 / NO), it returns to step S223. If the AF instruction has been canceled (step S229 / YES), it transmits a ranging process end instruction to the ranging device 50 (step S231) and ends the process of FIG. 7.

[0076] As described above, according to the second embodiment, when the defocus amount is within the first range, the body control unit 21 controls the position of the focus lens 31b. When the time during which the size of the object is less than a predetermined value continues for a certain time or more continuously, the control defocus amount range (the range of the defocus amount for controlling the position of the focus lens 31b) is switched to a second range that is narrower than the first range. Thereby, when the defocus amount is calculated for rain, snow, etc. existing in front of the main subject, since the calculated defocus amount is outside the second range, the focus lens 31b is not driven, and it is possible to suppress the drive of the focus lens 31b from becoming unstable.

[0077] In addition, in the second embodiment described above, when the number of times the body control unit 21 detects that the size of the object is less than a predetermined value continues for a predetermined number of times or more continuously, the position of the focus lens 31b may be controlled based on the calculated defocus amount. Alternatively, when the time during which the size of the object is less than a predetermined value continues for a certain time or more continuously, the position of the focus lens 31b may be controlled based on the calculated defocus amount. That is, when the defocus amount for rain or snow is calculated continuously a plurality of times, since it is highly likely that there is rain or snow such that the main subject cannot be confirmed, the position of the focus lens 31b may be controlled based on the calculated defocus amount.

[0078] In the first and second embodiments described above, the case where there is water splash, snow, or rain between the main subject and the camera 1 has been described. However, the first and second embodiments can also be applied when there are obstacles such as a net (such as a wire mesh) between the main subject and the camera 1. In this case, for example, it may be determined whether the minimum dimension of the object is less than a threshold value.

[0079] <<Third Embodiment>> The third embodiment suppresses focusing on an object that has been erroneously detected as a predetermined subject in a shooting mode for detecting a predetermined subject (for example, a person, an airplane, a bird). Since the configuration of the camera 1 is the same as that of the first and second embodiments, detailed description thereof is omitted.

[0080] FIG. 9 is a flowchart showing an example of the processing executed by the body control unit 21 in the third embodiment. Since the processing executed by the distance measuring device 50 is the same as that in the first embodiment, detailed description thereof is omitted.

[0081] The processing in FIG. 9 starts when the power of the camera body 2 is turned on. When the processing in FIG. 9 starts, the body control unit 21 waits until an AF instruction is received (step S301 / NO). When the body control unit 21 receives an AF instruction (step S301 / YES), it outputs a distance measurement processing start instruction to the control unit 503 of the distance measuring device 50 (step S303).

[0082] After transmitting the distance measurement processing start instruction, the body control unit 21 receives a distance image and information regarding the size of each object from the distance measuring device 50 (step S305).

[0083] In parallel with the processing in step S305, the body control unit 21 also executes a process of detecting a subject (subject detection process) set in advance according to the shooting mode (step S309). Specifically, the body control unit 21 detects, as a subject, an object set in advance according to the shooting mode in the image generated based on the signals from the imaging pixels of the imaging device 22. For example, if the shooting mode is the portrait mode, a human face is detected as the subject, if the shooting mode is the bird mode, a bird is detected as the subject, and if the shooting mode is the airplane mode, an airplane is detected as the subject. In the following description, it is assumed that the shooting mode is the portrait mode and the body control unit 21 detects a human face as the subject.

[0084] FIG. 10 shows an example of an image generated based on the signals from the imaging pixels of the imaging device 22. Here, in FIG. 10, the body control unit 21 detects, as subjects, the face of the main subject MSB1 and the face of a person in a poster photographed together with the main subject MSB1. In this case, the body control unit 21 sets subject detection frames CVF1 to CVF3 surrounding the detected subjects.

[0085] Next, the body control unit 21 determines whether the actual size of the subject (detected subject) detected according to the shooting mode preset in the camera 1 is within a predetermined range (step S311). Specifically, the body control unit 21 detects, as the subject, an object that has been predetermined according to the shooting mode in the image generated based on the signals from the imaging pixels of the imaging device 22.

[0086] The body control unit 21 obtains, for example, the size of the subject detection frame CVF3 using the distance image. Next, the body control unit 21 determines whether the actual size of the subject, which is the size of the subject detection frame CVF3, is within a predetermined range defined as the size of a human face.

[0087] If the actual size of the detected subject is not within the predetermined range (step S311 / NO), the body control unit 21 determines whether there is another subject detection frame (step S317). In FIG. 10, for example, since the size of the subject detection frame CVF3 is outside the predetermined range defined as the size of a human face, the determination in step S311 is NO, and the process proceeds to step S317. Then, since there are other subject detection frames CVF2 and CVF1, the determination in step S317 is YES.

[0088] If there is another subject detection frame (step S317 / YES), the process returns to step S311. Also for the subject detection frame CVF2, since its size is outside the predetermined range defined as the size of a human face, the determination in step S311 is NO. Then, since there is the subject detection frame CVF1, step S317 is YES, and the process returns to step S311.

[0089] Here, when the size of the subject detection frame CVF1 is within a predetermined range defined as the size of a human face (step S311 / YES), the body control unit 21 determines whether the subject within the subject detection frame CVF1 has unevenness based on the distance image (step S313). For example, there may be cases where symbols or characters printed on a signboard or the like are misdetected as a human face. At this time, if the size of the character is within the predetermined range defined as the size of a human face, focusing will be performed on the misdetected subject. Therefore, in this third embodiment, it is determined whether the detected subject has unevenness based on the distance image, and it is determined whether the detected subject is the subject to be detected (human face). This is because if it is a human face, the subject has unevenness.

[0090] When the detected subject has unevenness (step S313 / YES), the body control unit 21 performs a focus detection process on the subject detection frame CVF1 (step S314). Then, based on the defocus amount calculated in the focus detection process of step S314, the target position of the focus lens 31b is calculated, and the focus lens 31b is driven (step S315). As a result, the focusing accuracy on the subject specified in advance according to the shooting mode is improved. On the other hand, when the detected subject has no unevenness (step S313 / NO), the process proceeds to step S317.

[0091] After the end of step S315, or when the determination in step S317 is NO, the body control unit 21 determines whether the AF instruction has been canceled (step S319). If the AF instruction has not been canceled (step S319 / NO), the process returns to the processes of step S305 and step S309.

[0092] When the AF instruction has been canceled (step S319 / YES), the body control unit 21 transmits a ranging process end instruction to the ranging device 50 (step S321), and ends the process of FIG. 9.

[0093] As described in detail above, according to the third embodiment, the body control unit 21 controls the position of the focus lens 31b based on the information on the size of the object in the distance image and the information on the type of the object (for example, a human face, an airplane, a bird) specified in advance as the detection target. Thereby, for example, when a human face is set as the detection target, the body control unit 21 can determine whether the detected object is a human face from the size of the object detected as the subject that can be obtained from the distance image, so that it is possible to suppress focusing on an object other than the object specified in advance as the detection target (an object misrecognized as the detection target).

[0094] Also, in the third embodiment, when the size of the object is within the range of the size preset according to the type of the object specified in advance as the detection target, the body control unit 21 calculates the defocus amount based on the signal output from the focus detection pixel corresponding to the region including the object, and controls the position of the focus lens 31b. Thereby, it is possible to focus on the object specified in advance as the detection target.

[0095] Also, in the third embodiment, the body control unit 21 determines whether the object has unevenness based on the distance image, and controls the position of the focus lens 31b based on the type of the object specified in advance as the detection target, the size of the object, and whether the object has unevenness. Thereby, even when a symbol, character, or photograph printed on a flat surface such as a signboard is misrecognized as a human face, it is possible to suppress focusing on the symbol, character, or photograph misrecognized as a human face.

[0096] In the first to third embodiments described above, the camera 1 includes the distance measuring device 50, but the distance measuring device 50 may be detachable from the camera 1. In this case, the processes of FIGS. 2, 7, and 9 are started when the power of the camera body 2 is turned on and the distance measuring device 50 is attached to the camera 1.

[0097] In addition, in the first to third embodiments described above, the interchangeable lens 3 was a zoom lens with a variable focal length, but the interchangeable lens 3 may be a single-focus lens. Further, in the first and second embodiments, the interchangeable lens 3 was detachable from the camera body 2, but the present invention is not limited thereto, and the interchangeable lens 3 and the camera body 2 may be integrated.

[0098] In addition, in the first to third embodiments, the generation unit 505 of the distance measuring device 50 generated information regarding the size of each object based on the distance image, but the present invention is not limited thereto. The control unit 503 of the distance measuring device 50 may transmit the distance image to the body control unit 21, and the body control unit 21 may generate information regarding the size of each object based on the distance image.

[0099] In addition, in the first to third embodiments, the body control unit 21 determined whether an AF instruction was received (Figs. 2, 7, 9), but in addition to determining whether an AF instruction was received, it may also determine whether a moving image shooting instruction was received. That is, the first to third embodiments can also be applied to the shooting of moving images.

[0100] In addition, in the first to third embodiments, the body control unit 21 of the camera body 2 transmitted a distance measurement start instruction, and when the control unit 503 of the distance measuring device 50 received the distance measurement start instruction, it started the distance measurement process, but the present invention is not limited thereto. The control unit 503 of the distance measuring device 50 may start the distance measurement process when the power of the camera body 2 is turned on and the power of the distance measuring device 50 is turned on. The control unit 503 of the distance measuring device 50 may execute the distance measurement process at predetermined time intervals while the power of the distance measuring device 50 is turned on, and transfer the distance image and the information regarding the size of each object to the body control unit 21.

[0101] The processes executed by the body control unit 21 described in the first to third embodiments may be arbitrarily combined.

[0102] The above-described embodiments are preferred examples of the present invention. However, the present invention is not limited thereto, and various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0103] 1 Camera 2 Camera Body 3 Interchangeable Lens 21 Body Control Unit 22 Image Sensor 31 Imaging Optical System 31b Focusing Lens 50 Distance Measuring Device 501 Light Emitting Unit 502 Light Receiving Unit 503 Control Unit

Claims

1. A distance measuring device including a light emitting unit that emits light, a light receiving unit that receives light reflected by an object from the light emitted by the light emitting unit, and a generation unit that generates information regarding the distance to the object based on the light receiving result of the light receiving unit; An imaging device including an imaging element including pixels that receive light that has passed through an optical system including a focus lens and output information used for focus detection; A control unit that controls the position of the focus lens based on the information regarding the distance to the object and the information used for focus detection; The imaging device comprising the above.

2. The generation unit included in the distance measuring device generates information regarding the size of the object based on the information regarding the distance to the object, and the control unit controls the position of the focus lens based on the information regarding the size of the object and the information used for focus detection. The imaging device according to Claim 1.

3. The control unit generates information regarding the size of the object based on the information regarding the distance to the object, and controls the position of the focus lens based on the information regarding the size of the object and the information used for focus detection. The imaging device according to Claim 1.

4. When the size of the object is equal to or greater than a predetermined value, the control unit controls the position of the focus lens based on the information used for focus detection. The imaging device according to any one of Claims 1 to 3.

5. The control unit acquires information regarding the distance to the object at predetermined time intervals, and when the number of consecutive times the size of the object is less than the predetermined value is equal to or greater than a predetermined number of times, controls the position of the focus lens based on the information used for focus detection. The imaging device according to Claim 4.

6. When the size of the object is less than the predetermined value, the control unit controls the position of the focus lens based on the information used for focus detection output from the pixels provided in a region other than the region including the object. The imaging device according to Claim 4 or Claim 5.

7. The control unit controls the position of the focus lens within a first defocus range, and when the time during which the size of the object based on the information regarding the distance to the object is less than a predetermined value continues for a certain time or longer, switches the range of the defocus amount for controlling the position of the focus lens to a second defocus range that is narrower than the first defocus range. The imaging device according to any one of claims 1 to 5.

8. When the size of the object is less than the predetermined value, the control unit controls the position of the focus lens based on either the information used for the focus detection before it is determined that the size of the object is less than the predetermined value or the information regarding the distance to the object before it is determined that the size of the object is less than the predetermined value. The imaging device according to any one of claims 4 to 7.

9. The generation unit generates a distance image indicating the distance to the object. The control unit controls the position of the focus lens based on the information regarding the size of the object based on the information regarding the distance to the object included in a predetermined region based on the distance image and the information regarding the type of the object designated in advance as the detection target. The imaging device according to any one of claims 1 to 8.

10. When the size of the object is within the range of the size preset according to the type of the object designated in advance as the detection target, the control unit controls the position of the focus lens based on the information used for the focus detection output from the pixel corresponding to the region including the object. The imaging device according to claim 9.

11. The control unit determines whether the object has unevenness based on the distance image, and controls the position of the focus lens based on the type of the object designated in advance as the detection target, the size of the object, and whether the object has unevenness. The imaging device according to claim 10.

12. When the size of the object is within the range of the size preset according to the type of the object designated in advance as the detection target and the object has unevenness, the control unit controls the position of the focus lens based on the information used for the focus detection output from the pixel corresponding to the region including the object. The imaging device according to claim 11.

13. An acquisition unit that acquires information regarding the distance to the object from a distance measurement device having a light emitting unit that emits light, a light receiving unit that receives the light reflected by the object from the light emitting unit, and a generation unit that generates information regarding the distance to the object based on the light receiving result of the light receiving unit. An image sensor including a pixel that receives light that has passed through an optical system including a focus lens and outputs information used for focus detection; A control unit that controls the position of the focus lens based on information regarding the distance to the object and the information used for the focus detection; An imaging device comprising the same.

Images