JP2008129082A - Image taking device and light emission control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To alleviate a subject's feeling of glare by radiation of an AF assist beam without needing a special operation beforehand, and secure the precision of focusing on the subject as much as possible. <P>SOLUTION: A camera 100 judges whether there is a chief subject in an adjacent position that an AF assist beam output by an AF assist beam lamp 105b sufficiently reaches before focusing starts in response to the half pressing of a release switch 104, and, if there is a chief subject in the adjacent position, prohibits the AF assist beam lamp 105b from emitting beams. That is, it is possible to prevent the chief subject in the adjacent position from feeling glare due to radiation of an AF assist beam without a photographer performing a special operation before starting automatic focusing (before half pressing a release switch 104). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a camera that performs focus adjustment and distance measurement using auxiliary light (AF auxiliary light) for automatic focus adjustment.

2. Description of the Related Art Conventionally, a technique is known in which focus detection can be accurately performed even with low luminance by irradiating a subject with AF auxiliary light prior to photographing. Patent Document 1 relates to such a technique.
JP 2005-234367 A

  When the AF auxiliary light hits the face of the subject, the subject feels dazzling, and in some cases, the eyes may be closed during shooting. Although there are cameras that can prohibit the AF auxiliary light emission by the photographer's switch operation, usually the photographer rarely pays attention to the AF auxiliary light emission, and the subject's face is illuminated and feels dazzling, Therefore, it is often the case that the switch operation is performed for the first time to prohibit the emission of AF auxiliary light. In addition, the AF auxiliary light emission may be uniformly prohibited by a switch operation in advance, but in that case, the accuracy of focus detection is always lowered.

  The present invention has been made in view of such problems, and can reduce the sensation of the glare of the subject due to the irradiation of the AF auxiliary light without requiring any special operation in advance, and can improve the focusing accuracy on the subject. The purpose is to ensure as much as possible.

  The present invention relates to an image sensor that receives light incident from a subject via a photographic lens, continuously converts it into an image signal, and outputs the image signal that is output from the image sensor. A data conversion unit, a focus adjustment instruction unit for inputting a focus adjustment instruction to the photographing lens, and a focus on the subject of the photographing lens based on image data from the image data conversion unit in response to an input of the focus adjustment instruction to the focus adjustment instruction unit Focus adjustment unit that performs adjustment, auxiliary light emission unit that irradiates the subject with auxiliary light for focus adjustment at the time of focus adjustment by the focus adjustment unit, recording instruction unit that inputs an instruction to record image data, and photographing by the focus adjustment unit Provided with a recording unit that records image data of an imaging signal output from the imaging device at the time of input of a recording instruction to a recording instruction unit that is arbitrarily input after completion of focus adjustment of the lens About the image apparatus.

  An imaging apparatus according to the present invention includes a face detection unit that detects a face area of a subject based on image data output from an image data conversion unit before a focus adjustment instruction is input to the focus adjustment instruction unit, and a face detection A selection unit that selects a main subject that is a subject having the largest face area from among the detected face regions, a ranging unit that measures a distance to the selected main subject of the selection unit, and at least a measurement unit. A light emission control unit that prohibits the auxiliary light emitting unit from irradiating auxiliary light when the distance to the most main subject measured by the distance unit is within a predetermined proximity range.

  According to the present invention, when at least the most main subject (subject having the largest face area) exists in a predetermined proximity range before the focus adjustment instruction is input to the focus adjustment instruction unit, the auxiliary light emission is prohibited. Control to do. Although the most important subject is considered to be the most important subject among the subjects, the present invention automatically prohibits the auxiliary light from being irradiated from a close distance to the most important subject, and assists the most important subject. You can shoot comfortably without making the light feel dazzling.

  However, if the main subject is not in the proximity range, it is possible to irradiate auxiliary light, so that auxiliary light irradiation is prohibited by switch operation as before, and the accuracy of automatic focus adjustment is sacrificed uniformly. Absent.

  The imaging apparatus according to the present invention includes an irradiation position adjusting unit that adjusts the irradiation position of the auxiliary light on the subject by the auxiliary light emitting unit, and image data conversion before the focus adjustment instruction is input to the focus adjustment instruction unit. A face detection unit that detects a face area of a subject based on image data output from the unit, an eye detection unit that detects eyes from the face area detected by the face detection unit, and a face area detected by the face detection unit A sorting unit that sorts out the main subject that is a subject having the largest face area, a distance measuring unit that measures the distance to the selected main subject of the sorting unit, and at least the main subject measured by the ranging unit When the distance up to is within a predetermined proximity range, the emission position adjusting unit is controlled to adjust the irradiation position of the auxiliary light by the auxiliary light emitting unit to a position other than the eyes detected by the eye detection unit in the face area A control unit.

  According to the present invention, when at least the most main subject exists in a predetermined proximity range before the focus adjustment instruction is input to the focus adjustment instruction unit, the irradiation position of the auxiliary light is set to a position other than the eyes of the face region of the most main subject. Adjust to position. Since the present invention irradiates auxiliary light on the face of the main subject while avoiding irradiating auxiliary light from the close distance to the eyes of the main subject, the main subject does not feel the auxiliary light dazzling. Focus adjustment with high accuracy can be performed on the subject.

  The light emission control method according to the present invention is used in the imaging apparatus described above. This method includes a step of detecting a face area of a subject based on image data output from an image data conversion section before a focus adjustment instruction is input to the focus adjustment instruction section, and the most of the detected face areas. A step of selecting a main subject that is a subject having a large face area; a step of measuring a distance to the selected main subject; and at least the measured distance to the main subject within a predetermined proximity range In some cases, the method includes a step of prohibiting irradiation of auxiliary light by the auxiliary light emitting unit.

  The light emission control method according to the present invention is used in the imaging apparatus described above. This method includes a step of detecting a face area of a subject based on image data output from an image data conversion section before a focus adjustment instruction is input to the focus adjustment instruction section, and an eye from the detected face area. At least a step of detecting, a step of selecting a most main subject which is a subject having a face area having the largest area among the detected face regions, a step of measuring a distance to the selected main subject Adjusting the irradiation position of the auxiliary light by the auxiliary light emitting unit to a position other than the eyes detected by the eye detection unit in the face area when the distance to the main subject is within a predetermined proximity range.

  According to the present invention, control is performed so as to prohibit the emission of auxiliary light when at least the main subject is present in a predetermined proximity range. According to the present invention, it is prohibited to irradiate auxiliary light from a close distance to the main subject, and the main subject can be comfortably photographed without making the auxiliary light feel dazzling.

  According to the present invention, when at least the most main subject exists in a predetermined proximity range, the irradiation position of the auxiliary light is adjusted to a position other than the eyes of the face region of the most main subject. Since the present invention irradiates auxiliary light on the face of the main subject while avoiding irradiating auxiliary light from the close distance to the eyes of the main subject, the main subject does not feel the auxiliary light dazzling. Focus adjustment with high accuracy can be performed on the subject.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a front view of a digital camera (hereinafter abbreviated as a camera) 100 according to a preferred embodiment of the present invention.

  A lens barrel 60 provided in front of the camera 100 includes a photographic lens 101 including a zoom lens 101a and a focus lens 101b, and the focal length is adjusted by moving the zoom lens 101a in the optical axis direction. In addition, focus adjustment is performed by moving the focus lens 101b in the optical axis direction.

  The lens barrel 60 is advanced from the camera body 180 by moving forward and backward between the wide end, which is the shortest focal length position, and the tele end, which is the longest focal length position, from the state where the lens barrel 60 is retracted. Also stored. In this figure, a state in which the lens barrel 60 is retracted into the camera body 180 is shown.

  Further, the camera 100 creates a state in which the photographing lens 101 is protected by covering the front surface of the photographing lens 101 and blocking the photographing lens 101 and the outside when not photographing, and a lens cover 61 that exposes the photographing lens to the outside when photographing. Is provided.

  The lens cover 61 is configured by a mechanism that can be freely opened and closed. The lens cover 61 covers the front surface of the photographing lens 101 in an open state, and exposes the front surface of the photographing lens 101 to the outside in a closed state. The lens cover 61 is opened / closed in conjunction with the power switch 121 being turned on / off. In this figure, the lens cover 61 is open.

  On the upper surface of the camera 100, a mode dial 123 and a power switch 121 provided with a release switch 104 at the center are provided, and a strobe 105a, an AF auxiliary light lamp 105b, a self-timer lamp 105c, and the like are provided on the front. Has been deployed.

  FIG. 2 is a rear view of the camera 100. A zoom switch 127 is provided on the back of the camera 100. When the wide (W) side of the zoom switch 127 is pressed, the lens barrel 60 is extended to the wide end (telephoto) side while being pressed, and when the other side of the tele (T) side is pressed, the lens barrel 60 is being pressed. The lens barrel 60 moves to the tele end (wide angle) side.

  On the back of the camera 100, an image display LCD 102, a cross key 124, an information position designation key 126, and the like are also provided. The cross key 124 is an operation system for setting display brightness adjustment / self-timer / macro shooting / flash shooting on the top, bottom, left and right respectively. As will be described later, by pressing the lower key of the cross key 124, the main CPU 20 can set the self-photographing mode in which the CCD 132 performs the shutter operation after the time measurement of the self-timer circuit 83 is completed.

  FIG. 3 is a block diagram of the camera 100 according to the first embodiment. The camera 100 is provided with an operation unit 120 for performing various operations when the user uses the camera 100. The operation unit 120 includes a power switch 121 for turning on the power for operating the camera 100, a mode dial 123 for selecting auto shooting, manual shooting, and the like, and setting and selection of various menus or zooming. A cross key 124, a flash emission switch 125, and an information position designation key 126 for executing or canceling the menu selected by the cross key 124 are provided.

  In addition, the camera 100 is provided with an image display LCD 102 for displaying captured images, reproduced images, and the like, and an operation LCD display 103 for assisting operations.

  The camera 100 is provided with a release switch 104. The release switch 104 transmits a shooting start instruction to the main CPU 20. In the camera 100, switching between photographing and reproduction can be freely performed on a predetermined menu screen. Further, the camera 100 is provided with a flash light emitting device having an AF auxiliary light lamp 105b composed of a light emitting diode (LED) for irradiating a subject with a light projection spot during contrast AF, and a strobe 105a that emits flash light.

  In addition, the camera 100 includes a photographing lens 101, a diaphragm 131, and a CCD sensor 132 (hereinafter referred to as an image sensor) that converts a subject image formed through the photographing lens 101 and the diaphragm 131 into an analog image signal. Abbreviated as CCD 132). The CCD 132 generates an image signal by accumulating charges generated by subject light irradiated on the CCD 132 for a variable charge accumulation time (exposure period). The CCD 132 sequentially outputs image signals for each frame at a timing synchronized with the vertical synchronization signal VD output from the CG unit 136.

  When the CCD 132 is used as the image sensor, an optical low-pass filter 132a that removes unnecessary high-frequency components in the incident light is disposed in order to prevent the generation of color false signals and moire fringes. In addition, an infrared cut filter 132b that absorbs or reflects infrared light in incident light and corrects a sensitivity characteristic unique to the CCD sensor 132 having high sensitivity in a long wavelength region is provided. The specific arrangement of the optical low-pass filter 132a and the infrared cut filter 132b is not particularly limited.

  The camera 100 also adjusts the white balance of the subject image represented by the analog image signal from the CCD sensor 132 and adjusts the slope (γ) of the straight line in the gradation characteristics of the subject image, and further amplifies the analog image signal. A white balance / γ processing unit 133 including an amplifier with a variable gain is provided.

  Further, the camera 100 includes an A / D converter 134 that A / D converts an analog signal from the white balance / γ processing unit 133 into digital R, G, B image data, and an A / D converter 134. A buffer memory 135 for storing R, G, B image data is provided.

  The R, G, B image data obtained by the A / D conversion unit 134 is also input to the AF detection unit 150. The AF detection unit 150 averages the R, G, B image data for each predetermined divided area of the screen and for each same color component, and further integrates the R, G, B image data of all areas for each frame. Average values Ir, Ig, and Ib are calculated. The integrated average values Ir, Ig, and Ib are used as the amounts of R, G, and B visible light received.

  However, the R, G, and B visible light receiving amounts Ir, Ig, and Ib can be detected by a light receiving sensor (not shown) other than the CCD 132 that has sensitivity to the R, G, and B visible lights, respectively. is there.

  Further, the camera 100 includes a CG (clock generator) unit 136, a photometry / ranging CPU 137, a charge / light emission control unit 138, a communication control unit 139, a YC processing unit 140, and a power supply battery 68. It has been.

  The CG unit 136 includes a vertical synchronization signal VD for driving the CCD sensor 132, a drive signal including a high-speed sweep pulse P, a control signal for controlling the white balance / γ processing unit 133, the A / D conversion unit 134, and communication control. A control signal for controlling the unit 139 is output. Further, a control signal from the photometry / ranging CPU 137 is input to the CG unit 136.

  The photometry / ranging CPU 137 controls the zoom motor 110, the focus motor 111, and the aperture motor 112 for adjusting the aperture to drive the zoom lens 101a, the focus lens 101b, and the aperture 131, respectively, thereby driving the distance to the subject. Is calculated (ranging), and the CG unit 136 and the charge / light emission control unit 138 are controlled. Driving of the zoom motor 110, the focus motor 111, and the aperture motor 112 is controlled by the motor driver 62, and a control command for the motor driver 62 is sent from the photometry / ranging CPU 137 or the main CPU 20.

  The driving source of the zoom lens 101a, the focus lens 101b, the stop 131, and the AF auxiliary light irradiation angle is not necessarily limited to various motors such as the zoom motor 110, the focus motor 111, and the stop motor 112. It may be.

  The CPU 137 for photometry / ranging is based on image data (through image) obtained periodically (every 1/30 seconds to 1/60 seconds) by the CCD 132 when the release switch 104 is half-pressed (S1 is turned on). Measure the brightness of the subject (calculate EV value).

  That is, the AE calculation unit 151 integrates the R, G, and B image signals output from the A / D conversion unit 134 and provides the integrated values to the photometry / ranging CPU 137. The photometry / ranging CPU 137 detects the average brightness (subject brightness) of the subject based on the integrated value input from the AE calculation unit 151, and calculates an exposure value (EV value) suitable for photographing.

  Then, the photometry / ranging CPU 137 determines the exposure value including the aperture value (F value) of the aperture 131 and the electronic shutter (shutter speed) of the CCD 132 based on the obtained EV value according to a predetermined program diagram. (AE operation).

  When the release switch 104 is fully pressed (S2 is turned on), the photometry / ranging CPU 137 drives the aperture 131 based on the determined aperture value, controls the aperture diameter of the aperture 131, and determines the determined shutter speed. Based on the above, the charge accumulation time in the CCD 132 is controlled via the CG 136.

  The AE operation includes an aperture priority AE, a shutter speed priority AE, a program AE, etc. In any case, the subject brightness is measured, and an exposure value determined based on the photometric value of the subject brightness, that is, an aperture value and a shutter. By taking a picture in combination with the speed, control is performed so that an image is taken with an appropriate exposure amount, and it is possible to save troublesome determination of exposure.

  The AF detection unit 150 extracts image data corresponding to the detection range selected by the photometry / ranging CPU 137 from the A / D conversion unit 134. The method of detecting the focal position is performed using the feature that the high frequency component of the image data has the maximum amplitude at the in-focus position. The AF detection unit 150 calculates an amplitude value by integrating the high-frequency component of the extracted image data for one field period. The AF detector 150 is configured such that the photometry / ranging CPU 137 drives and controls the focus motor 111 to move the focus lens 101b within the movable range, that is, between the end point (INF point) on the infinity side and the end point (NEAR point) on the near side. When the maximum amplitude is detected, the detection value is transmitted to the photometry / ranging CPU 137 when the maximum amplitude is detected.

  The photometry / ranging CPU 137 obtains this detection value and issues a command to the focus motor 111 to move the focus lens 101b to the corresponding in-focus position. The focus motor 111 moves the focus lens 101b to the in-focus position in accordance with a command from the photometry / ranging CPU 137 (AF operation).

  The photometry / ranging CPU 137 is connected to the release switch 104 through inter-CPU communication with the main CPU 20, and the in-focus position is detected when the release switch 104 is half-pressed by the user. Further, a zoom motor 110 is connected to the photometry / ranging CPU 137, and when the main CPU 20 acquires a zoom command from the user in the TELE direction or WIDE direction, the zoom motor 110 is used. By driving the motor 110, the zoom lens 101a is moved between the WIDE end and the TELE end.

  The charging / light emission control unit 138 is supplied with electric power from the power supply battery 68 in order to cause the strobe 105a to emit light, and charges a flash light emitting capacitor (not shown) or controls light emission of the strobe 105a.

  The charging / light emission control unit 138 sends various signals such as charging start of the power supply battery 68, a half-press / full-press operation signal of the release switch 104, and signals indicating the light emission amount and the light emission timing to the main CPU 20 and the photometry / ranging CPU 137. Is supplied to the self-timer lamp 105c and the AF auxiliary light lamp 105b, and control is performed so that a desired light emission amount is obtained at a desired timing.

  Note that the self-timer lamp 105c may be constituted by an LED, or may be made common with the LED constituting the AF auxiliary light lamp 105b.

  A self-timer circuit 83 is connected to the main CPU 20. When the self-photographing mode is set, the main CPU 20 measures time based on the full-press signal of the release switch 104. During this timing, the main CPU 20 causes the self-timer lamp 105c to blink while gradually increasing the blinking speed in accordance with the remaining time via the photometry / ranging CPU 137. The self-timer circuit 83 inputs a timing completion signal to the main CPU 20 after timing is completed. The main CPU 20 causes the CCD 132 to perform a shutter operation based on the timing completion signal.

  The communication control unit 139 includes a communication port 107. The communication control unit 139 outputs an image signal of a subject photographed by the camera 100 to an external device such as a personal computer equipped with a USB terminal. In addition, by inputting an image signal from such an external device to the camera 100, data communication with the external device is performed. The camera 100 also has a function of simulating the function of switching to ISO sensitivity 80, 100, 200, 400, 1600, etc. of a normal camera that takes a photograph on a roll-shaped photographic film, and has an ISO sensitivity of 400 or more. When switched, the high-sensitivity mode is set in which the amplification factor of the amplifier of the white balance / γ processing unit 133 is set to a high amplification factor exceeding a predetermined amplification factor. The communication control unit 139 stops communication with the external device during shooting in the high sensitivity mode.

  The camera 100 also includes a compression / decompression & ID extraction unit 143 and an I / F unit 144. The compression / decompression & ID extraction unit 143 reads and compresses the image data stored in the buffer memory 135 via the bus line 142 and stores the image data in the memory card 200 via the I / F unit 144. In addition, the compression / decompression & ID extraction unit 143 extracts an identification number (ID) unique to the memory card 200 and reads the image data stored in the memory card 200 when reading the image data stored in the memory card 200. Are decompressed and stored in the buffer memory 135.

  The Y / C signal stored in the buffer memory 135 is compressed in accordance with a predetermined format by the compression / decompression & ID extraction unit 143, and then the removable medium such as the memory card 200 or the hard disk (HDD) 75 via the I / F 144. Are recorded in a predetermined format (for example, an Exif (Exchangeable Image File Format) file). Data recording to the hard disk (HDD) 75 or reading of data from the hard disk (HDD) 75 is controlled by the hard disk controller 74 in accordance with a command from the main CPU 20.

  The camera 100 includes a main CPU 20, an EEPROM 146, a YC / RGB conversion unit 147, and a display driver 148. The main CPU 20 controls the entire camera 100. The EEPROM 146 stores solid data and programs unique to the camera 100. The YC / RGB conversion unit 147 converts the color video signal YC generated by the YC processing unit 140 into RGB signals of three colors, and outputs them to the image display LCD 102 via the display driver 148.

  In addition, the camera 100 has a configuration in which an AC adapter 48 for obtaining power from an AC power supply and a power supply battery 68 are detachable. The power battery 68 is composed of a rechargeable secondary battery such as a nickel-cadmium battery, a nickel metal hydride battery, or a lithium ion battery. The power supply battery 68 may be a single-use primary battery such as a lithium battery or an alkaline battery. The power supply battery 68 is electrically connected to each circuit of the camera 100 by being loaded into a battery storage chamber (not shown).

  When the AC adapter 48 is loaded in the camera 100 and power is supplied from the AC power source to the camera 100 via the AC adapter 48, the power supply battery 68 is preferential even if it is loaded in the battery storage chamber. The power output from the AC adapter 48 is supplied to each part of the camera 100 as driving power. If the AC adapter 48 is not loaded and the power battery 68 is loaded in the battery storage chamber, the power output from the power battery 68 is supplied to each part of the camera 100 as driving power. Is done.

  Although not shown, the camera 100 is provided with a backup battery separately from the power supply battery 68 housed in the battery housing chamber. For example, a dedicated secondary battery is used as the built-in backup battery and is charged by the power supply battery 68. The backup battery supplies power to the basic functions of the camera 100 when the power battery 68 is not loaded in the battery storage chamber, such as when the power battery 68 is replaced or removed.

  That is, when the power supply from the power supply battery 68 or the AC adapter 48 is stopped, the backup battery is connected to the RTC 15 or the like by a switching circuit (not shown) and supplies power to these circuits. As a result, as long as the backup battery 29 does not reach the end of its life, power supply continues to the basic functions such as the RTC 15 without interruption.

  An RTC (Real Time Clock) 15 is a chip dedicated to timekeeping, and continuously operates by receiving power supply from the backup battery even when power supply from the power supply battery 68 or the AC adapter 48 is turned off.

  The image display LCD 102 is provided with a backlight 70 that illuminates the transmissive or transflective liquid crystal panel 71 from the back side. In the power saving mode, the main CPU 20 determines the brightness of the backlight 70 ( Brightness) is controlled through the backlight driver 72, and the power consumption of the backlight 70 is reduced. In the power saving mode, the information position designation key 126 of the operation unit 120 is pressed to display a menu screen on the image display LCD 102, and a predetermined operation can be performed on the menu screen so that on / off can be set. It has become.

  FIG. 4 conceptually shows a program executed by the main CPU 20 in a block diagram. The main CPU 20 includes a face extraction unit 20a, a face size detection unit 20b, a main subject selection unit 20c, and an AF auxiliary light emission control unit 20d, which are programs stored in a computer-readable storage medium such as the EEPROM 146 and the hard disk 75, in the RAM 145. Etc. to read and execute. These are sometimes simply called a program.

  The face extraction unit 20a extracts a face area that is an area including a human face portion from through images sequentially stored in the buffer memory 135. As a face area extraction method, for example, the technique disclosed in Japanese Patent Laid-Open No. 9-101579 “Face Area Extraction Method and Copying Condition Determination Method” by the present applicant can be applied.

  This technology determines whether or not the hue of each pixel of the captured image is included in the skin color range and divides it into a skin color region and a non-skin color region, and detects edges in the image to detect each pixel in the image. The location is classified as an edge portion or a non-edge portion. Then, an area surrounded by pixels that are located in the skin color area and classified as a non-edge part and surrounded by pixels that are determined to be edge parts is extracted as a face candidate area, and the extracted face candidate area becomes a human face. A corresponding region is determined, and a face region is extracted based on the determination result. In addition, a face region can be extracted by a method described in Japanese Patent Application Laid-Open Nos. 2003-209683 and 2002-199221.

  The face size detection unit 20b detects the size of the face area extracted by the face extraction unit 20a. If there are a plurality of extracted face regions, the size of each is detected.

  The main subject selection unit 20c selects the main subject, which is a subject having the largest face area among the face areas detected by the face size detection unit 20b.

  The AF auxiliary light emission control unit 20d uses the photometry / ranging CPU 137 to calculate the distance to the most main subject selected by the most main subject selection unit 20c. If the distance D to the most main subject is within a predetermined proximity range R (for example, a range of 0 m to 2 m or 3 m which is a proximity distance where the AF auxiliary light reaches sufficiently), the most main subject is in the proximity position. And the charge / light emission control unit 138 is commanded to prohibit the light emission of the AF auxiliary light lamp 105b.

  FIG. 5 shows an example of the most main subject selected from a plurality of face regions. Here, of the four face regions, the subject located on the left end side of the angle of view is selected as the main subject.

  Since the face area of the most main subject is the largest, it can be considered as the most important person (for example, a child who is a central person in the family) who wants to remain as an image among the persons who are the subject. However, the subject is not necessarily a human and may be a living organism other than a human. Also, if it is necessary to shoot by avoiding strong AF auxiliary light from a close distance and the object can detect the face area, draw a modeled object or human face. It may be a painting. If the detected face area is one, the subject having the face area is selected as the most main subject.

  Hereinafter, the flow of shooting processing performed by the camera 100 will be described with reference to the flowchart of FIG.

  In S1, the face extraction unit 20a performs face detection from the through image. The face size detection unit 20b detects the size of each face area extracted from the through image by the face extraction unit 20a. Then, the main subject selection unit 20c selects the main subject having the largest face area.

  In S2, the AF auxiliary light emission control unit 20d instructs the photometry / ranging CPU 137 to calculate the distance to the most main subject (ranging).

  In S3, the AF auxiliary light emission control unit 20d determines whether or not the release switch 104 is half-pressed. If half-pressed, the process proceeds to S4. If not half-pressed, the process proceeds to S1.

  In S4, the AF auxiliary light emission control unit 20d determines whether or not the distance D to the most main subject is within a predetermined proximity range R. If the distance D is within the predetermined proximity range R, the process proceeds to S5, and if the distance D is not within the predetermined proximity range R, the process proceeds to S6.

  In S5, the AF auxiliary light emission controller 20d instructs to prohibit the AF auxiliary light lamp 105b from emitting light. Thereafter, the focus position is detected and the AF operation is performed. However, since the AF auxiliary light lamp 105b is prohibited from emitting light, the focus position may not be detected accurately. Therefore, detection of the focal position may be omitted, and the AF operation may be completed by moving the focus lens 101b to a standard focus position such as pan focus.

  In S6, the charging / light emission control unit 138 controls the light emission of the AF auxiliary light lamp 105b to detect the focal position and perform the AF operation.

  In S7, in response to the release switch 104 being fully pressed, the CCD 132 is caused to perform a shutter operation to acquire image data for recording.

  If face detection cannot be performed in S1, it is considered difficult to perform focus adjustment without irradiation of AF auxiliary light because the surroundings are too dark. Therefore, if face detection is not possible in S1, or if detection is possible, the detection accuracy is lower than a predetermined threshold (for example, accuracy of 50%), the process proceeds to S6, and AF auxiliary light may be emitted.

  As described above, the camera 100 according to the present embodiment determines whether or not the main subject is present at a close position where the AF auxiliary light emitted from the AF auxiliary light lamp 105b reaches sufficiently. If it is determined before the automatic focus adjustment is started in response to the push, and the most main subject is present in the proximity position, the AF auxiliary light lamp 105b is prohibited from emitting light. That is, even if the photographer does not perform a special operation before the focus adjustment is started (before the release switch 104 is half-pressed), the AF auxiliary light is irradiated to an important subject at a close position to make it feel dazzling. Can be prevented.

  In addition, if an important subject is at a relatively remote position where the AF auxiliary light does not feel dazzling, the emission of the AF auxiliary light is not prohibited. Can be done.

<Second Embodiment>
Instead of prohibiting the light emission of the AF auxiliary light lamp 105b itself, the sensation of glare of the subject may be reduced by changing the irradiation spot by adjusting the angle of the optical axis of the AF auxiliary light lamp 105b.

  FIG. 7 is a block diagram of the camera 100 according to the second embodiment. The camera 100 includes an optical axis angle adjustment motor 114. When the optical axis angle adjustment motor 114 is driven by the drive signal from the CPU 20, the AF auxiliary light lamp 105b changes the angle of the optical axis of the AF auxiliary light lamp 105b within a plane including the optical axis of the photographing optical system. Driven by.

  In addition to extracting a face area, the face extraction unit 20a detects an eye area where an eye exists from the extracted face area. The eye region can be detected from the relative positional relationship of the approximate face center position obtained as a result of face detection. The face extraction unit 20a can also detect facial components other than the mouth, nose, ears, forehead, head, chin, and other eyes from the relative positional relationship of the approximate face center position.

  The AF auxiliary light emission control unit 20d uses the photometry / ranging CPU 137 to calculate the distance to the most main subject selected by the most main subject selection unit 20c. If the distance D to the main subject is within the predetermined proximity range R, it is determined that the main subject is in the proximity distance. Then, the AF auxiliary light emission control unit 20d controls the optical axis angle adjustment motor 114, and the position (for example, mouth, nose, ear, forehead, forehead, etc.) other than the eyes in the face area of the main subject detected by the face extraction unit 20a. The optical axis angle of the AF auxiliary light lamp 105b is adjusted so that the AF auxiliary light is irradiated to the detection position of the facial component other than the head, chin, and other eyes.

  The adjustment amount of the optical axis angle may be determined according to the positional relationship between the constituent parts of the face, such as half the distance between the eyes detected by the face extraction unit 20a. In addition, when the detection accuracy of the face component of the face extraction unit 20a is different for each component, the optical axis angle is adjusted so that the AF auxiliary light is irradiated toward the component other than the eye with the highest detection accuracy. Good. In this way, the probability that the AF auxiliary light is irradiated to the constituent parts of the face other than the eyes increases.

  FIG. 8 illustrates a state in which the AF auxiliary light is irradiated to the mouth detection position, which is an example of the position other than the eyes of the most main subject, as a result of controlling the optical axis angle adjustment motor 114. Although illustration is omitted, the optical axis angle of the AF auxiliary light lamp 105b is adjusted so that the AF auxiliary light is irradiated to the detection position of the constituent parts of the face other than the nose, ears, forehead, head, chin and the like. May be.

  Other configurations and functions of the camera 100 are the same as those in the first embodiment and FIG.

  Hereinafter, the flow of the photographing process performed by the camera 100 will be described with reference to the flowchart of FIG.

  In S11, the face extraction unit 20a performs face detection from the through image. The face size detection unit 20b detects the size of each face area extracted from the through image by the face extraction unit 20a. Then, the main subject selection unit 20c selects the main subject having the largest face area.

  In S12, the AF auxiliary light emission control unit 20d instructs the photometry / ranging CPU 137 to calculate the distance to the most main subject (ranging).

  In S13, the AF auxiliary light emission control unit 20d determines whether or not the release switch 104 is half-pressed. If half-pressed, the process proceeds to S14. If not half-pressed, the process proceeds to S11.

  In S14, the AF auxiliary light emission control unit 20d determines whether or not the distance D to the main subject is within a predetermined proximity range R. If it is within the proximity range R, the process proceeds to S15, and if not within the proximity range R, the process proceeds to S16.

  In S15, the AF auxiliary light emission control unit 20d controls the optical axis angle adjustment motor 114 so that the AF auxiliary light is irradiated to a position other than the eyes in the face area of the most main subject detected by the face extraction unit 20a. The optical axis angle of the AF auxiliary light lamp 105b is adjusted. Thereafter, the charging / light emission control unit 138 controls the light emission of the AF auxiliary light lamp 105b, and performs the focus position detection and the AF operation.

  In S16, the charging / light emission control unit 138 controls the light emission of the AF auxiliary light lamp 105b, and performs the focus position detection and the AF operation.

  In S17, in response to the release switch 104 being fully pressed, the CCD 132 is caused to perform a shutter operation to acquire image data for recording.

  As described above, in the camera 100 according to the present embodiment, the AF auxiliary light lamp 105b is the most important when the most important subject exists at a close position where the AF auxiliary light irradiated by the AF auxiliary light lamp 105b sufficiently reaches. The optical axis angle is adjusted so that the AF auxiliary light is irradiated to positions other than the eyes of the subject's face. That is, it is possible to irradiate the AF auxiliary light without making an important subject feel dazzling, and to perform accurate focus adjustment without sacrificing the detection accuracy of the focal position as much as possible.

Front view of digital camera Rear view of digital camera Block diagram of a digital camera according to the first embodiment A diagram conceptually showing a program executed by the main CPU A figure showing an example of the selected main subject The flowchart which shows the flow of the imaging | photography process which concerns on 1st Embodiment. Block diagram of a digital camera according to the second embodiment The figure which shows a mode that AF auxiliary light was irradiated to positions other than the eyes of the face of the main subject The flowchart which shows the flow of the imaging | photography process which concerns on 2nd Embodiment.

Explanation of symbols

20: main CPU, 101: photographing lens, 105b: AF auxiliary light lamp, 114: optical axis angle adjustment motor, 132: CCD, 134: A / D converter, 150: AF detector, 151: AE calculator

Claims (4)

An image sensor that receives light incident from a subject via a photographic lens, continuously converts it into an imaging signal, and outputs it, and an image data converter that converts the imaging signal output from the imaging element into image data and outputs the image data A focus adjustment instruction unit that inputs a focus adjustment instruction of the photographic lens, and the image of the photographic lens based on image data from the image data conversion unit in response to the input of the focus adjustment instruction to the focus adjustment instruction unit A focus adjustment unit that performs focus adjustment on a subject, an auxiliary light emitting unit that irradiates the subject with auxiliary light for focus adjustment when the focus adjustment is performed by the focus adjustment unit, and a recording instruction unit that inputs an instruction to record the image data And at the time of inputting the recording instruction to the recording instruction unit arbitrarily input after the focus adjustment of the photographing lens by the focus adjustment unit is completed. An imaging apparatus comprising a recording unit for recording the image data of the force by the imaging signal,
A face detection unit that detects a face area of the subject based on image data output from the image data conversion unit before the focus adjustment instruction is input to the focus adjustment instruction unit;
A selection unit for selecting a main subject that is a subject having the largest face area among the face areas detected by the face detection unit;
A distance measuring unit for measuring a distance to the most main subject selected by the selecting unit;
A light emission control unit that prohibits the auxiliary light emitting unit from irradiating the auxiliary light when at least the distance measured by the distance measuring unit is within a predetermined proximity range;
An imaging apparatus comprising: An image sensor that receives light incident from a subject via a photographic lens, continuously converts it into an imaging signal, and outputs it, and an image data converter that converts the imaging signal output from the imaging element into image data and outputs the image data A focus adjustment instruction unit that inputs a focus adjustment instruction of the photographic lens, and the image of the photographic lens based on image data from the image data conversion unit in response to the input of the focus adjustment instruction to the focus adjustment instruction unit A focus adjustment unit that performs focus adjustment on a subject, an auxiliary light emitting unit that irradiates the subject with auxiliary light for focus adjustment when the focus adjustment is performed by the focus adjustment unit, and a recording instruction unit that inputs an instruction to record the image data And at the time of inputting the recording instruction to the recording instruction unit arbitrarily input after the focus adjustment of the photographing lens by the focus adjustment unit is completed. An imaging apparatus comprising a recording unit for recording the image data of the force by the imaging signal,
An irradiation position adjusting unit for adjusting an irradiation position of the auxiliary light to the subject by the auxiliary light emitting unit;
A face detection unit that detects a face area of the subject based on image data output from the image data conversion unit before the focus adjustment instruction is input to the focus adjustment instruction unit;
An eye detection unit for detecting eyes from the face area detected by the face detection unit;
A selection unit for selecting a main subject that is a subject having the largest face area among the face areas detected by the face detection unit;
A distance measuring unit for measuring a distance to the most main subject selected by the selecting unit;
When at least the distance to the main subject measured by the distance measuring unit is within a predetermined proximity range, the irradiation position adjusting unit is controlled so that the irradiation position of the auxiliary light by the auxiliary light emitting unit is the face region A light emission control unit for adjusting to a position other than the eyes detected by the eye detection unit,
An imaging apparatus comprising: An image sensor that receives light incident from a subject via a photographic lens, continuously converts it into an imaging signal, and outputs it, and an image data converter that converts the imaging signal output from the imaging element into image data and outputs the image data A focus adjustment instruction unit that inputs a focus adjustment instruction of the photographic lens, and the image of the photographic lens based on image data from the image data conversion unit in response to the input of the focus adjustment instruction to the focus adjustment instruction unit A focus adjustment unit that performs focus adjustment on a subject, an auxiliary light emitting unit that irradiates the subject with auxiliary light for focus adjustment when the focus adjustment is performed by the focus adjustment unit, and a recording instruction unit that inputs an instruction to record the image data Output from the image sensor at the time of input of the recording instruction to the recording instruction section arbitrarily input after the focus adjustment of the photographing lens by the focus adjustment section is completed. And a light emission control method used in an image pickup apparatus including a recording unit for recording the image data of the image signal,
Detecting a face area of the subject based on image data output from the image data conversion unit before the focus adjustment instruction is input to the focus adjustment instruction unit;
Selecting a main subject that is a subject having the largest face area among the detected face areas; and
Measuring the distance to the selected main subject;
When at least the measured distance to the main subject is within a predetermined proximity range, prohibiting irradiation of the auxiliary light by the auxiliary light emitting unit; and
A light emission control method comprising: An image sensor that receives light incident from a subject via a photographic lens, continuously converts it into an imaging signal, and outputs it, and an image data converter that converts the imaging signal output from the imaging element into image data and outputs the image data A focus adjustment instruction unit that inputs a focus adjustment instruction of the photographic lens, and the image of the photographic lens based on image data from the image data conversion unit in response to the input of the focus adjustment instruction to the focus adjustment instruction unit A focus adjustment unit that performs focus adjustment on a subject, an auxiliary light emitting unit that irradiates the subject with auxiliary light for focus adjustment when the focus adjustment is performed by the focus adjustment unit, and a recording instruction unit that inputs an instruction to record the image data Output from the image sensor at the time of input of the recording instruction to the recording instruction section arbitrarily input after the focus adjustment of the photographing lens by the focus adjustment section is completed. Recording unit that records the image data of the image signal, and said a light emission control method used in an imaging apparatus including an irradiation position adjusting unit for adjusting by the auxiliary light emitting portion the irradiation position of the auxiliary light to the subject,
Detecting a face area of the subject based on image data output from the image data conversion unit before the focus adjustment instruction is input to the focus adjustment instruction unit;
Detecting eyes from detected face areas;
Selecting a main subject that is a subject having the largest face area among the detected face areas; and
Measuring the distance to the selected main subject;
When at least the measured distance to the main subject is within a predetermined proximity range, the irradiation position of the auxiliary light by the auxiliary light emitting unit is adjusted to a position other than the eyes detected by the eye detection unit in the face region And steps to
A light emission control method comprising:

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