JP6577737B2 - IMAGING DEVICE, ITS CONTROL METHOD, PROGRAM, AND STORAGE MEDIUM - Google Patents

Description

  The present invention relates to a focus detection technique during astronomical photography.

  Recent digital cameras can easily perform astronomical photography, which has been difficult in the past, by improving noise reduction technology and dramatically improving image quality through high-sensitivity photography. By the way, when photographing a celestial body, focusing is one of the most difficult camera settings. When focusing using the AF (autofocus) function of the camera, depending on the composition, the light source of the night scene on the ground that is brighter than the stars may be in focus. It was necessary to change the focus.

  In Patent Document 1, when the elevation angle of the camera is equal to or greater than a certain angle, a desired focus can be achieved without changing the AF algorithm by enlarging the size or increasing the number of focus detection areas set with high priority. A method for realizing the state is described.

  Further, Patent Document 2 describes a method of changing the position and size of the focus detection area in accordance with the change in image magnification, because the size and position of the subject in the screen change due to the change in the image magnification of the camera. ing.

JP 2012-128021 A JP 2014-006477 A

  Conventionally, in AF that automatically focuses on a light source such as a star during celestial photography, if a night scene on the ground is reflected in the AF frame (focus detection area), focus on the light source of the night scene on the ground that is not a star. There is a possibility.

  When performing astronomical photography in Japanese Patent Laid-Open No. 2004-260260, shooting is often performed with a composition including a ground scene as a foreground, and the proportion of the night scene on the ground changes in the shooting screen according to the change in the shooting angle of view of the lens. . For this reason, it is difficult to accurately detect a night scene on the ground and to expand the focus detection area except for the night scene on the ground.

  When performing astronomical photography in Patent Document 2, since a plurality of light sources in the photographing screen become subjects, it is not necessary to be very aware of the size and position of the image accompanying the change in image magnification.

  The present invention has been made in view of the above problems, and an object of the present invention is to realize a focus detection technique that makes it difficult to focus on a light source other than a desired subject when performing astronomical photography.

In order to solve the above-described problems and achieve the object, the imaging apparatus of the present invention includes a setting unit that sets a plurality of focus detection areas in a captured image output from the imaging element, and the setting from the output of the imaging element. Processing means for generating evaluation information indicating the in-focus state of the subject in the focus detection area set by the means, attitude detection means for detecting the attitude information of the apparatus, and an angle of view detection means for detecting shooting angle of view information The ground portion of the plurality of focus detection areas set by the setting means based on the attitude information of the device obtained by the attitude detection means and the shooting angle-of-view information obtained by the angle-of-view detection means. evaluation information and evaluation data of the other focus detection areas in the focus detection area including, towards the evaluation information of the focus detection area including the aerial part is weighted so is low, the weighting at the time of performing focus detection A determining means for constant for, a.

  According to the present invention, it is possible to realize a focus detection technique that makes it difficult to focus on a light source other than a desired subject when performing astronomical photography or the like.

The block diagram which shows the apparatus structure of embodiment which concerns on this invention. The figure explaining the attitude | position detection method at the time of imaging | photography. The figure explaining the imaging | photography angle of view detection method. The figure explaining the method of extracting a ground part from the imaging | photography screen. The figure explaining the determination method of the focus detection area | region containing a ground part. The figure explaining the relationship between the angle of view at the time of imaging | photography using a wide angle lens, and an elevation angle. The figure explaining the relationship between a field angle at the time of imaging | photography using a telephoto lens, and an elevation angle. 6 is a flowchart showing weight determination processing for a focus detection area according to the present embodiment. The flowchart which shows the detail of the attitude | position detection process in FIG. The flowchart which shows the detail of the horizon position detection process in FIG.

  Hereinafter, embodiments for carrying out the present invention will be described in detail. The embodiment described below is an example for realizing the present invention, and should be appropriately modified or changed according to the configuration and various conditions of the apparatus to which the present invention is applied. It is not limited to the embodiment. Moreover, you may comprise combining suitably one part of each embodiment mentioned later.

  In this embodiment, an example in which the imaging apparatus of the present invention is realized by a digital camera having an autofocus (AF) function will be described. However, a focus mounted on an electronic device such as a smartphone or a tablet terminal which is a kind of mobile phone. The present invention can also be applied to a detection device.

  <Apparatus Configuration> With reference to FIG. 1, the configuration of an imaging apparatus equipped with a focus detection apparatus for realizing the AF function of this embodiment will be described.

  As shown in FIG. 1, the digital camera of this embodiment includes a camera body 100, a lens unit 200, and a recording medium 300.

  First, the internal configuration of the lens unit 200 will be described.

  The lens unit 200 can be attached to and detached from the camera body 100, and a connector 201 for electrical connection with the camera body 100 is provided. The connector 201 of the lens unit 200 serves as an interface for exchanging information, signals, and the like with the connector 197 provided in the camera body 100, and enables communication with the camera body 100.

  The lens unit 200 includes a zoom lens 202, a focus lens 203, and a shutter 204 having a diaphragm function, which are arranged in front of an image sensor 114 that converts an optical image of a subject into an electrical signal.

  The lens unit 200 may be configured so as to be built in the camera body 100 and cannot be removed like a compact camera.

  Next, the internal configuration of the camera body 100 will be described.

  The subject image light that has passed through the lens unit 200 is imaged on the image sensor 114. The image sensor 114 includes a photoelectric conversion element such as a CCD or CMOS that converts an optical image of a subject into an electrical signal. The gain amplifier 115 amplifies the analog signal output of the image sensor 114 and sets the sensitivity of the camera.

  The A / D converter 116 converts the analog signal output from the image sensor 114 and amplified by the gain amplifier 115 into digital image data. The timing generator 118 supplies a clock signal and a control signal to the image sensor 114, the A / D converter 116, and the D / A converter 126 under the control of the memory control unit 122 and the system control unit 150.

  The image processing unit 120 performs resize processing and color conversion processing such as predetermined pixel interpolation and reduction on the data from the A / D converter 116 or the data from the memory control unit 122. The image processing unit 120 performs predetermined calculation processing using the captured image data, and the system control unit 150 performs exposure control and distance measurement control based on the obtained calculation result. Thereby, AF (autofocus) processing, AE (automatic exposure) processing, and EF (flash pre-emission) processing of the TTL (through-the-lens) method are performed. The image processing unit 120 further performs predetermined calculation processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained calculation result.

  The memory control unit 122 controls the A / D converter 116, the timing generation unit 118, the image processing unit 120, the image display memory 124, the D / A converter 126, the memory 130, and the compression / decompression unit 132.

  The image data output from the A / D converter 116 is written into the memory 130 via the image processing unit 120 and the memory control unit 122 or only through the memory control unit 122. The memory 130 stores image data obtained by the image sensor 114 and converted into a digital signal by the A / D converter 116. The image display memory (video memory) 124 stores image data to be displayed on the image display unit 128. The memory 130 has a sufficient storage capacity to store a predetermined number of still images and a predetermined time of moving images and audio. As a result, even during continuous shooting, a large amount of images can be written in the memory 130 at high speed. Note that the memory 130 may also be used as the image display memory 124.

  The memory 130 can also be used as a work area for the system control unit 150. Further, the memory 130 also has a function of storing focus position information of the focus control unit 142 for zooming control of the zoom control unit 144.

  The D / A converter 126 converts the image display data stored in the image display memory 124 into an analog signal and supplies the analog signal to the image display unit 128. Thus, the display image data written in the image display memory 124 is displayed by the image display unit 128 via the D / A converter 126. The image display unit 128 performs display according to the analog signal from the D / A converter 126 on a display such as an LCD. The A / D converter 116 A / D converts the image data temporarily stored in the image display memory 124 into analog signals in the D / A converter 126 and sequentially transfers them to the image display unit 128 for display. Thus, it functions as an electronic viewfinder and can display a through image (also referred to as a live view image).

  The compression / decompression unit 132 compresses / decompresses image data using a known image compression method such as adaptive discrete cosine transform (ADCT). The compression / decompression unit 132 reads an image stored in the memory 130, performs compression processing or decompression processing, and writes the processed data to the memory 130 again.

  The exposure control unit 140 controls the shutter 204 and the gain amplifier 115 of the lens unit 200 in accordance with instructions from the system control unit 150 based on the photometric information measured by the TTL via the memory control unit 122.

  The focus control unit 142 performs AF processing by driving the focus lens 203 in accordance with an instruction from the system control unit 150 based on the phase difference detection result of the subject image.

  The zoom control unit 144 performs zooming control for driving the zoom lens 202 of the lens unit 200 in accordance with an instruction from the system control unit 150 based on the zoom operation of the user.

  The shutter switch 160 is turned on when a shutter button (not shown) is being operated, so-called half-press (shooting preparation instruction), and generates a first shutter switch signal SW1. In response to the first shutter switch signal SW1, operations such as AF processing, AE processing, AWB processing, and EF processing are started.

  Further, the shutter switch 160 is turned on when the operation of a shutter button (not shown) is completed, so-called full press (shooting instruction), and generates a second shutter switch signal SW2. In response to the second shutter switch signal SW2, the system control unit 150 starts a series of photographing processing operations from reading a signal from the image sensor 114 to writing image data on the recording medium 300. A series of imaging processes uses an exposure process in which a signal read from the image sensor 114 is written to the memory 130 via the A / D converter 116 and the memory control unit 122, and an operation in the image processing unit 120 and the memory control unit 122. Development processing, and recording processing for reading image data from the memory 130, performing compression by the compression / decompression unit 132, and writing the image data to the recording medium 300.

  The operation unit 162 includes operation members such as various switches, buttons, and a touch panel that receive various operations from the user. The system control unit 150 performs various operations in accordance with input signals from the operation unit 162. The operation unit 162 includes, for example, a menu button, a set button, a macro button, a multi-screen playback page break button, a strobe setting button, and a single shooting / continuous shooting / self-timer switching button. In addition to the auto mode, the program mode, the aperture priority mode, and the shutter speed priority mode, the user operates the operation unit 162, as well as the astronomical shooting mode, night view mode, child shooting mode, fireworks shooting mode, underwater shooting mode, and the like. , Settings can be selected according to various shooting scenes.

  In addition, the operation unit 162 includes a menu movement + (plus) button, a menu movement − (minus) button, a reproduction image movement + (plus) button, a reproduction image − (minus) button, an imaging quality selection button, an exposure correction button, a date. Has a date / time setting button.

  The posture detection unit 163 uses an acceleration sensor (gravity sensor), a gyro, or the like, and using the detection result, the system control unit 150 can detect the posture (elevation angle, roll angle, etc.) of the camera body 100 as will be described later. It is.

  The nonvolatile memory 165 is an electrically erasable / recordable memory, and for example, an EEPROM or the like is used. The nonvolatile memory 165 stores operation constants, programs, and the like for the system control unit 150. Here, the program is a program for executing various flowcharts including a focus detection process described later in the present embodiment.

  The system control unit 150 controls the entire digital camera. By executing the program recorded in the nonvolatile memory 165 described above, the focus detection process of the present embodiment is realized. The system memory 166 is a memory for operating the system control unit 150, and a RAM is used. In the system memory 166, constants and variables for operation of the system control unit 150, programs read from the nonvolatile memory 165, and the like are expanded. The system control unit 150 also performs display control by controlling the memory 130, the D / A converter 126, the image display unit 128, and the like.

  The information display unit 167 includes an LCD, a speaker, and the like that display and output the operation state of the camera, messages, and the like using characters, images, sounds, and the like according to instructions from the system control unit 150. One or a plurality of positions are arranged at positions that are easily visible.

  Among the display contents of the information display unit 167, what is displayed on the LCD or the like includes single shot / continuous shooting shooting display, self-timer display, compression rate display, recording pixel number display, recording number display, remaining image number display, There are shutter speed display, aperture value display, and exposure compensation display.

  Also, what is displayed on the LCD or the like includes red-eye reduction display, macro imaging display, buzzer setting display, battery remaining amount display, error display, and information display with multiple digits. Further, what is displayed on the LCD or the like includes an attachment / detachment state display of the recording medium 300 and a date / time display.

  The power supply control unit 181 includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, and detects whether or not a battery is installed, the type of battery, and the remaining battery level. Further, the power supply control unit 181 controls the DC-DC converter according to the detection result and an instruction from the system control unit 150, and supplies a necessary voltage to each unit including the recording medium 300 for a necessary period.

  The power supply unit 186 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a lithium ion battery, an AC adapter, or the like.

  The power supply control unit 181 and the power supply unit 186 are connected by connectors 182 and 184.

  The recording medium 300 is a recording medium such as a memory card or a hard disk for recording captured images, and includes a recording unit 302, a recording medium I / F 304, and a connector 306. The recording unit 302 includes a semiconductor memory, a magnetic disk, or the like. The recording medium I / F 304 is an interface with the recording unit 302.

  The camera body 100 includes a connector 192 to which the connector 306 of the recording medium 300 is connected and a recording medium I / F 190 that is an interface with the recording medium 300.

  As the recording medium interface 190 and the connector 192, those conforming to a standard such as an SD (registered trademark) card are used.

  In addition, the camera body 100 is connected to an external device through a wired cable connected to the antenna of the wireless communication unit 198 or the communication connector 194 so as to transmit / receive images, sounds, and other information. In addition, the camera body 100 can be connected to a wireless LAN (Local Area Network) or the Internet via the wireless communication unit 198 or the communication connector 194.

  Next, functional blocks for the system control unit 150 to realize focus detection according to the present embodiment will be described.

  The system control unit 150 includes an elevation angle acquisition block 151, a roll angle acquisition block 152, a ground portion extraction block 153, a field angle detection block 154, a focus detection area determination block 155, and a weight determination block 156.

  The elevation angle acquisition block 151 calculates elevation angle information at the time of shooting of the camera body 100 described later with reference to FIG. 4 using the detection result by the acceleration sensor as the posture detection unit 163.

  The roll angle acquisition block 152 functions as an inclination detection unit that calculates roll angle information (inclination about the optical axis) at the time of shooting of the camera body 100 using a detection result by the acceleration sensor as the posture detection unit 163.

  The angle-of-view detection block 154 uses the elevation angle information calculated by the elevation angle acquisition block 151, the roll angle information calculated by the roll angle acquisition block 152, the focal length information of the zoom lens 202 obtained by the zoom control unit 144, and the like. The shooting field angle information of the lens is calculated.

  The ground extraction block 153 uses the elevation angle information calculated by the elevation angle acquisition block 151, the roll angle information calculated by the roll angle acquisition block 152, and the shooting angle information calculated by the field angle detection block 154 to capture the image on the imaging screen. The position of the ground part included in is calculated. Here, the terrestrial part is exemplified as a horizon indicating the boundary between the sky and the surface part of the subject area existing on the ground and the ground other than the starry sky and the celestial body, for example, the concept including the topography, structures, water surfaces such as rivers and the sea It is.

  The focus detection area determination block 155 sets a plurality of focus detection areas on the imaging surface of the image sensor 114. The focus detection area determination block 155 determines whether or not there is a focus detection area including the ground part obtained by the ground part extraction block 153 or, if there is, the position of the focus detection area including the ground part.

  The weight determination block 156 determines the weight indicating the reliability of each focus evaluation information of the focus detection area according to the determination result by the focus detection area determination block 155. The focus evaluation information corresponds to, for example, a defocus amount indicating the focused state of the subject in AF using a phase difference detection method.

  The system control unit 150 further includes processing means for generating focus evaluation information for each focus detection area from the output signal of the image sensor 114, focus detection means for performing focus detection by performing predetermined weighting on each focus evaluation information, Based on the obtained focus position information, the focus control unit 142 is controlled to function as a focus adjustment unit that performs AF.

  <Attitude and angle of view of camera body at the time of photographing> Next, referring to FIGS. 2 to 4, a method of calculating the posture (elevation angle and roll angle) and angle of view of the camera body 100 of the present embodiment at the time of photographing. Will be described.

  FIG. 2 shows the axial direction of the camera body 100 detected by an acceleration sensor used as the attitude detection unit 163 of the digital camera of this embodiment. In FIG. 2, when the optical axis direction of the camera body 100 is a Z axis, a vertical direction is defined as a Y axis and a horizontal direction is defined as an X axis among two axes orthogonal to the Z axis that is an optical axis. As for the output value from the acceleration sensor, the value in the Z-axis direction becomes zero when the optical axis is horizontal, whereas the value in the Z-axis direction becomes −1g when the optical axis is directed in the vertical direction. Using this characteristic, the elevation angle is calculated as the first posture information of the camera body 100 by the change in the output value of the acceleration sensor in the Z-axis direction. Further, the output values in the X-axis direction and the Y-axis direction are also detected based on the same principle as in the Z-axis direction, and the roll angle (tilt around the Z-axis) is used as the second posture information of the camera body 100 from the output values in the three-axis direction. Can be calculated.

  The posture detection of the camera body 100 is not limited to a method using an acceleration sensor, and may be realized using other means such as a gyro.

  FIG. 3 shows the shooting angle of view of the lens. In FIG. 3, when the vertical size (Y-axis direction) size of the imaging surface of the imaging element 114 is a and the focal length of the zoom lens 202 is b, the shooting angle of view θ of the lens can be calculated by the following formula 1. .

θ = 2 * arcTan ((a / 2) / b) [rad] (1)
In other words, the shooting angle of view θ of the lens increases as the imaging surface size a of the image sensor 114 increases, and decreases as the focal length b increases.

  FIG. 4 shows a method of calculating the position of the horizon as a predetermined subject area in the shooting screen by changing the elevation angle of the camera body 100.

  FIG. 4A shows the size of the imaging surface of the image sensor 114. The maximum value of the shooting angle of view θ of the lens is the diameter of the image circle, but since the shooting angle of view θ is determined by the vertical size of the imaging surface, here the size of the imaging surface in the vertical direction (Y-axis direction) is av. The size in the horizontal direction (X-axis direction) is defined as ah.

  FIG. 4B shows the relationship between the shooting field angle θ and the elevation angle γ when the camera body 100 is seen through from the side including the optical axis. If the angle formed by the optical axis direction of the camera body 100 and the horizontal direction (horizon line) of the ground part (horizon line) is an elevation angle, the horizon line on the imaging surface is at a position passing through the center of the optical axis when the elevation angle is 0 °. When the elevation angle becomes γ (> 0 °) from this state, the position of the horizon is calculated with the ratio of the shooting angle of view θ as the ratio A / B of the size av on the imaging surface.

  If the moving distance of the horizon from the optical axis center on the imaging surface is A and the size from the vertical optical axis center of the imaging surface is B, the moving distance A of the horizon on the imaging surface at the elevation angle γ is It can be approximated by the following formula 2.

A≈ (γ / θ) · B · 2 (2)
FIG. 4C shows the positional relationship between the elevation angle of the camera body 100 and the horizon on the imaging surface. FIG. 4C shows that the horizon on the imaging surface is a position moved by a distance A from the center of the optical axis. That is, when the first focus detection region to the third focus detection region are set in three rows in the vertical direction in the captured image as shown in FIG. 4C, the horizon is detected as the second focus due to the change in elevation angle. This indicates that the region has moved to the third focus detection region.

  Note that the size B from the center of the optical axis in the vertical direction of the imaging surface changes depending on the roll angle that is the inclination of the camera body 100 around the optical axis, and B when the camera body 100 is in a horizontal state (normal position, horizontal position). = Av / 2, and in the vertical state (vertical position), B = ah / 2.

  <Relationship Between Shooting Field Angle and Elevation Angle> Next, with reference to FIGS. 5 and 6, the manner in which the shooting field angle of the lens changes in accordance with the elevation angle change of the camera body 100 of this embodiment will be described.

  FIG. 5 shows a change in the shooting angle of view when the elevation angle of the camera body 100 is changed when a wide-angle lens is attached to the camera body 100.

  FIG. 5A shows a state where the camera body 100 is placed in a horizontal state to perform astronomical photography, and in the focus detection areas in which the imaging surface is divided into nine, the horizon lines appear in the lower six focus detection areas. It is crowded. In this case, in order to focus on the star as the light source of the celestial body, it is necessary to detect the in-focus position of the star using the focus evaluation information of the upper three focus detection areas.

  FIG. 5B shows a state in which the elevation angle of the camera body 100 is changed to δ ° from the horizontal state of FIG. In FIG. 6B, the horizon line is reflected in the lower three focus detection areas among the nine focus detection areas. In this case, the weight of the focus evaluation value of each focus detection area is determined so as to detect the in-focus position of the star using the focus evaluation information of the upper six focus detection areas.

  FIG. 5C shows a state where the elevation angle of the camera body 100 is changed to ε ° from the horizontal state of FIG. 5A (ε> δ). In this case, since the horizon is not reflected in any focus detection area, the focus evaluation information of each focus detection area is weighted so that the focus position of the star is detected using the focus evaluation information of all focus detection areas. decide.

  FIG. 6 shows a state in which the elevation angle of the camera body 100 is changed from 0 ° to δ ° when a telephoto lens is attached to the camera body 100.

  FIG. 6A shows a state in which astronomical photography is performed with the camera body 100 in a horizontal state, and in the focus detection area in which the imaging surface is divided into nine, the horizon is reflected in the lower six focus detection areas. It is crowded. In this case, in order to focus on the star as the light source of the celestial body, it is necessary to detect the in-focus position of the star using the focus evaluation information of the upper three focus detection areas.

  FIG. 6B shows a state in which the elevation angle of the camera body 100 is changed to δ ° from the horizontal state of FIG. In this case, since the horizon is not reflected in any focus detection area, the focus evaluation information of each focus detection area is weighted so that the focus position of the star is detected using the focus evaluation information of all focus detection areas. decide.

  5 and 6 that the amount of movement of the position of the imaging surface due to the elevation angle change of the camera body 100 is larger when the telephoto lens is attached than when the wide-angle lens is attached.

  The weighting method is a method of processing each focus evaluation value using a coefficient, a method of determining a focus evaluation value by comparison with a threshold value, or a focus evaluation value by relative comparison for each focus detection area. Various methods, such as a method of performing, can be applied.

  <Focus Detection Area Determination Method> Next, a method for determining the focus detection area including the horizon when the elevation angle of the camera body 100 changes will be described with reference to FIG.

  FIG. 7A shows the positional relationship between the horizon and the focus detection area when the elevation angle of the camera body 100 is 0 °. In FIG. 7A, since the horizon is at a position passing through the center of the optical axis, the horizon exists in the second focus detection region. In this case, the second focus detection area including the horizon is likely to be affected by the light source of the night scene on the ground. For this reason, the weighting of the focus evaluation information of the second focus detection region estimated to include the ground portion and the third focus detection region below the second focus detection region is higher than that of the first focus detection region above the second focus detection region. And set it low.

  FIG. 7B shows a state where the elevation angle of the camera body 100 is changed downward from the horizontal state of FIG. In FIG. 7B, the horizon exists in the first focus detection area. In this case, since all the focus detection areas including the horizon are likely to be affected by the light source of the night scene on the ground, the weight of the focus evaluation information of all the focus detection areas is set low.

  FIG. 7C shows a state in which the elevation angle of the camera body 100 is changed upward from the horizontal state of FIG. In FIG. 7C, since the horizon exists in the third focus detection region, the first focus detection above the focus evaluation information weighting of the third focus detection region estimated to include the ground part is performed. It is set lower than the area and the second focus detection area.

  FIG. 7D shows a state in which the elevation angle of the camera body 100 is changed further upward from the state of FIG. In FIG. 7D, the horizon exists below the lowermost third focus detection region. In this case, since all the focus detection areas are unlikely to be affected by the light source of the night scene on the ground, the weights of the focus evaluation values of all the focus detection areas are set high.

  In the illustrated example, a configuration in which three first focus detection areas to three third focus detection areas are set in the vertical direction is illustrated. However, a focus detection area divided into a plurality of vertical and horizontal directions is set. The same applies even if Further, even when the camera body 100 is tilted around the optical axis, it is determined whether the ground portion exists in any focus detection region according to the tilt (roll angle), and the same as described above. What is necessary is just to determine the weight of focus evaluation information.

  <Weighting Determination Process> Next, with reference to FIG. 8, a description will be given of the weighting determination process for the focus evaluation information of the focus detection area when the imaging apparatus of this embodiment performs focus detection.

  In the present embodiment, as shown in FIG. 7, three first focus detection areas, second focus detection areas, and third focus detection areas are set on the imaging surface in the vertical direction. . In the present embodiment, it is assumed that the horizon is used as the ground part and the subject area existing on the ground part. Needless to say, the present invention is not limited to these embodiments.

  The processing in FIG. 8 is executed during AF processing triggered by a shooting preparation instruction from the shutter switch 160 when the astronomical shooting mode is set. The flowchart of FIG. 8 is realized by developing a program read from the nonvolatile memory 165 by the CPU of the system control unit 150 into the system memory 166 and executing it. The same applies to flowcharts shown in FIGS. 9 and 10 described later.

  In step S800, the system control unit 150 detects the posture (elevation angle, roll angle) of the camera body 100.

  In step S801, the system control unit 150 detects the position of the horizon on the imaging surface.

  In step S802, the system control unit 150 determines whether or not the position of the horizon detected in step S801 in the focus detection area determination block 155 exists in the first focus detection area. As a result of the determination, if the horizon exists within the first focus detection area, the process proceeds to step S807, and if not, the process proceeds to step S803.

  In step S807, the system control unit 150 sets the weight of each focus evaluation information from the first focus detection area to the third focus detection area low in the weight determination block 156, and ends the process. This process corresponds to the state described with reference to FIG.

  In step S803, the system control unit 150 determines whether the horizon detected in step S801 in the focus detection area determination block 155 exists in the second focus detection area. As a result of the determination, if the horizon exists in the second focus detection region, the process proceeds to step S808, and if not, the process proceeds to step S804.

  In step S808, the system control unit 150 sets the weight of the focus evaluation information in the first focus detection area high in the weight determination block 156, and sets the weight of the focus evaluation information in the second focus detection area and the third focus detection area. Set it low and finish the process.

  In step S804, the system control unit 150 determines whether or not the horizon detected in step S801 in the focus detection area determination block 155 exists in the third focus detection area. As a result of the determination, if the horizon exists within the third focus detection area, the process proceeds to step S809, and if not, the process proceeds to step S805.

  In step S809, the system control unit 150 sets the weight of the focus evaluation information of the first focus detection area and the second focus detection area to be high in the weight determination block 156, and sets the weight of the focus evaluation information of the third focus detection area. Set it low and finish the process. This process corresponds to the state described with reference to FIG.

  In step S805, the system control unit 150 determines whether or not the horizon detected in step S801 in the focus detection area determination block 155 exists below the third focus detection area. As a result of the determination, if the horizon exists below the third focus detection area, the process proceeds to step S810; otherwise, the process proceeds to step S806.

  In step S810, the system control unit 150 determines that the optical axis of the camera body 100 is oriented in the zenith direction, and thus, in the weight determination block 156, each focus evaluation value from the first focus detection area to the third focus detection area. The information weighting is set high, and the process ends. This process corresponds to the state described with reference to FIG.

  In step S806, since the system control unit 150 can determine that the horizon is located above the first focus detection area, the weight of each focus evaluation information from the first focus detection area to the third focus detection area is set low, The process ends.

  <Attitude Detection Process> Next, with reference to FIG. 9, the attitude detection process of the camera body 100 in step S800 of FIG. 8 will be described.

  In the present embodiment, a method for detecting the posture (elevation angle, roll angle) of the camera body 100 using an acceleration sensor as the posture detection unit 163 will be described, but other means such as a gyro may be used.

  In step S900, the system control unit 150 acquires an output value in the Z-axis direction of the camera body 100 using an acceleration sensor.

In step S901, the system control unit 150 calculates the elevation angle of the camera body 100 using the output value in the Z-axis direction acquired in step S900 in the elevation angle acquisition block 151. In step S902, the system control unit 150 uses an acceleration sensor. The respective output values of the camera body 100 in the X axis direction and the Y axis direction are acquired.

  In step S903, the system control unit 150 calculates the roll angle of the camera body 100 using the output values in the X-axis direction and the Y-axis direction acquired in step S902 in the roll angle acquisition block 152.

  <Horizon Line Position Detection Processing> Next, the horizon position detection processing in step S801 in FIG. 8 will be described with reference to FIG.

  In step S <b> 1000, the system control unit 150 acquires focal length information of the zoom lens 202 in the view angle detection block 154.

  In step S1001, the system control unit 150 acquires posture information (elevation angle and roll angle) of the camera body 100 obtained by the process of FIG.

  In step S1002, the system control unit 150 acquires size information in the vertical direction (distance B = av / 2 in FIG. 4) as the effective pixel range of the imaging surface of the imaging device 114. Then, in the angle-of-view detection block 154, shooting angle-of-view information is calculated using the focal length information of the zoom lens 202 acquired in step S1000 and the size information of the imaging surface.

  In step S1003, the system control unit 150 determines the position of the horizon on the imaging surface (distance in FIG. 4) from the elevation angle of the camera body 100 acquired in step S1001 and the shooting angle of view information calculated in step S1002 in the ground part extraction block 153. A) is calculated.

  As described above, according to the present embodiment, when shooting a subject such as a star in the astrophotography mode, a starry sky or a night view of the ground other than the celestial body enters the composition, so that the ground It is difficult to perform focus detection that causes the light source to focus on the night view.

  In the present embodiment, weighting is determined for the focus evaluation information of a plurality of focus detection areas using the elevation angle of the camera body 100, but current position information (shooting position information) by GPS (Global Positioning System) and direction sensor In combination with the direction information, map information, and the like, the height in determining the weight for each focus detection area can be improved by estimating the height of the terrain and structures such as buildings in the shooting screen.

  In this embodiment, the weight of the focus evaluation information of the focus detection area including the horizon is set low, but the focus evaluation value of the focus detection area is set to zero and is not used for focus detection. Also good.

  In this embodiment, the focus evaluation information in the focus detection area including the horizon is reduced in weight so that it is difficult to focus on a light source other than the celestial body. The detection accuracy of a desired subject such as a star may be improved by considering the additional information.

  In the present embodiment, the weight of the focus detection area is determined according to the posture change of the camera body 100 and the shooting angle of view, but the focus evaluation information is weighted using the brightness distribution information in the shooting screen. Reliability can be increased.

  In the present embodiment, the horizon of the ground part is detected and the weight of the focus evaluation information in the focus detection area is determined. However, a starry sky or a celestial body may be detected as the subject area. In this case, it is only necessary to increase the weight of the focus evaluation information of the focus detection area including only the starry sky and the celestial body, and to decrease the weight of the focus evaluation information of the focus detection area including the other subject such as the ground.

  In the present embodiment, the focus detection area is set regardless of changes in the posture of the camera body 100 and the shooting angle of view. However, the size of the focus detection area depends on changes in the posture of the camera body 100 and the shooting angle of view. The sheath shape, number, position on the imaging surface, etc. may be changed.

[Other Embodiments]
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 100 ... Camera body, 150 ... System control part, 163 ... Attitude detection part, 151 ... Elevation angle acquisition block, 152 ... Roll angle acquisition block, 153 ... Ground part extraction block, 154 ... View angle detection block, 155 ... Focus detection area determination Block, 156 ... Weight determination block

Claims (13)

Setting means for setting a plurality of focus detection areas in the captured image output from the image sensor;
Processing means for generating evaluation information indicating an in-focus state of the subject in the focus detection area set by the setting means from the output of the imaging device;
Posture detection means for detecting posture information of the device;
Angle-of-view detecting means for detecting shooting angle-of-view information;
Based on the posture information of the apparatus obtained by the posture detection means and the shooting angle-of-view information obtained by the angle-of-view detection means , the ground portion is selected from the plurality of focus detection areas set by the setting means. Regarding the evaluation information of the focus detection area including the evaluation information and the evaluation information of the other focus detection areas, the weight for performing the focus detection is determined so that the evaluation information of the focus detection area including the ground portion has a lower weight. An imaging device comprising: a determination unit;   Setting means for setting a plurality of focus detection areas in the captured image output from the image sensor;
  Processing means for generating evaluation information indicating an in-focus state of the subject in the focus detection area set by the setting means from the output of the imaging device;
  Posture detection means for detecting posture information of the device;
  Angle-of-view detecting means for detecting shooting angle-of-view information;
  Of the plurality of focus detection areas set by the setting means, based on the attitude information of the device obtained by the attitude detection means and the shooting angle-of-view information obtained by the angle-of-view detection means, the starry sky and the celestial body The focus detection area evaluation information including at least one of the focus detection area and the other focus detection area evaluation information is evaluated so that the evaluation information other than the focus detection area including at least one of the starry sky and the celestial body has a lower weight. And an deciding means for deciding a weight when performing detection. Elevation angle acquisition means for obtaining elevation angle information of the apparatus at the time of photographing from the attitude information of the apparatus obtained by the attitude detection means;
Extraction means for extracting a predetermined subject area on the ground part included in the shooting screen based on the elevation angle information obtained by the elevation angle acquisition means and the shooting angle of view information obtained by the angle of view detection means;
A determination means for determining a focus detection area including at least the ground predetermined subject area obtained by the extraction means among the plurality of focus detection areas set by the setting means;
The determination unit, the evaluation information of the focus detection area determined by the determining means, the image pickup apparatus according to claim 1 or 2, characterized in that setting the weighting at the time of performing the focus detection low. Further comprising an inclination detecting means for obtaining an inclination around the optical axis of the apparatus at the time of photographing from the attitude information of the apparatus obtained by the attitude detecting means;
4. The determination unit according to claim 3 , wherein the determination unit determines a focus detection region including at least a predetermined subject region on the ground obtained by the extraction unit according to the inclination obtained by the inclination detection unit. The imaging device described. Said determining means according to claim 4, characterized in that setting a higher weighting of the evaluation information of the focus detection region located above the focus detection area including the aerial part predetermined subject region obtained by at least said extraction means The imaging device described in 1. Said determining means according to claim 5, characterized in that setting a low weighting of evaluation information of the focus detection region located below the focus detection area including the aerial part predetermined subject region obtained by at least said extraction means The imaging device described in 1. 5. The determination unit according to claim 3 or 4 , wherein, when it is determined from the elevation angle information that the optical axis of the apparatus is directed to a celestial body, the determination unit sets a high weighting of evaluation information of all focus detection areas. The imaging device described. When it is determined from the elevation angle information that the optical axis of the apparatus is directed to a predetermined subject area on the ground , the determination means sets the weight of evaluation information for all focus detection areas to be low. Item 5. The imaging device according to Item 3 or 4 . The aboveground predetermined subject area, the imaging apparatus according to any one of claims 3 to 8, characterized in that as an object region existing on the ground and the ground other than starry or astronomical. A control method for an image pickup apparatus, comprising: an attitude detection unit that detects an attitude of the device; and an angle-of-view detection unit that detects an angle of view during shooting,
A setting step for setting a plurality of focus detection areas in a captured image output from the image sensor;
A step of generating evaluation information indicating an in-focus state of a subject in the set focus detection area from the output of the image sensor;
Based on the posture information of the device obtained by the posture detection means and the shooting angle-of-view information obtained by the angle-of-view detection means, focus detection including the ground portion among the plurality of set focus detection areas. evaluation information and evaluation data of the other focus detection areas in the region, as it is weighted lower rating information of the focus detection area including the aerial part, a determination step of determining a weighting for performing focus detection And a method of controlling the imaging apparatus.   A control method for an imaging apparatus, comprising: an attitude detection unit that detects an attitude of the apparatus; and an angle-of-view detection unit that detects an angle of view at the time of shooting,
  A setting step for setting a plurality of focus detection areas in a captured image output from the image sensor;
  A step of generating evaluation information indicating an in-focus state of a subject in the set focus detection area from the output of the image sensor;
  Based on the posture information of the apparatus obtained by the posture detection means and the shooting angle of view information obtained by the angle of view detection means, at least one of the starry sky and the celestial body among the set focus detection areas. The focus detection is performed so that the weight of the evaluation information other than the focus detection area including at least one of the starry sky and the celestial body is lower than the evaluation information of the focus detection area including the focus information and the evaluation information of the other focus detection areas. And a determination step for determining the weighting at the time. The program for functioning a computer as each means of the imaging device described in any one of Claims 1 thru | or 9 . A computer-readable storage medium storing a program for causing a computer to function as each unit of the imaging apparatus according to any one of claims 1 to 9 .

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