JP2004179963A - Imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an image as a photographic intention by automatically changing the light volume of a flash (strobe). <P>SOLUTION: In a control means 41 of a camera main body 1, the serial imaging of a plurality of images is performed by automatically calculating a condition for imaging the plurality of images with the different mix ratio of the light volume of the flash and the light volume of background light, under which a main abject can be photographed at proper exposure. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an imaging apparatus such as a digital still camera, and more particularly to flash photography control thereof.
[0002]
[Prior art]
At the time of flash (strobe) shooting with a digital still camera, the ratio of the amount of flash light and the amount of background light (steady light) mixed to obtain an image with the intended atmosphere depends on the photographer. There were many parts that depended on experience and feeling, so it was difficult to shoot.
[0003]
In view of this, Japanese Patent Application Laid-Open No. H11-157210 proposes that an image using stationary light and an image using strobe light are continuously photographed and stored, and then added and synthesized at an arbitrary ratio.
[0004]
[Patent Document 1]
JP 2000-307941 A
[0005]
[Problems to be solved by the invention]
However, in the method of continuously photographing an image using the steady light and an image using the strobe light and storing the images continuously, the addition and combining are performed at an arbitrary ratio when the subject moves during the continuous shooting. This may result in an unnatural image.
[0006]
The present invention has been made under such a situation, and an object of the present invention is to obtain an image as intended by an image pickup apparatus by automatically changing the light amount of a flash (strobe) a plurality of times to obtain an image. Things.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, the imaging apparatus is configured as in the following (1) to (3), the imaging method is configured as in the following (4), and the program is stored in the following (5). Configure as follows.
[0008]
(1) background light amount determining means for determining a background light amount by a first exposure factor based on luminance information of a subject and a predetermined program chart or a set value;
First flash light amount determination means for determining a flash light amount for adding a main subject to an appropriate exposure by adding the background light amount at the time of imaging;
The second exposure factor is determined by subtracting a predetermined amount from the first exposure factor determined by the background light amount determination means, and is added to the background light amount based on the second exposure factor to make the main subject proper exposure. Flash light amount determining means for determining a second flash light amount for
The third exposure factor is determined by adding a predetermined amount to the first exposure factor determined by the background light amount determining means, and is added to the background light amount based on the third exposure factor to make the main subject proper exposure. Flash light amount determining means for determining a third flash light amount for
The first imaging is performed based on the first exposure factor determined by the background light intensity determination unit and the flash light intensity determined by the first flash light intensity determination unit, and the second exposure factor and the second exposure factor are determined. Control means for performing a second imaging based on a flash light amount, and controlling to perform a third imaging based on the third exposure factor and the third flash light amount;
An imaging device comprising:
[0009]
(2) In the imaging device according to (1),
The control means includes: first image information obtained by the first imaging; second image information obtained by the second imaging; and third image information obtained by the third imaging. Wherein the white balance adjustment amounts are the same.
[0010]
(3) An image pickup apparatus characterized by comprising a control means for automatically controlling a plurality of images in which the mix ratio between the light amount of the flash light and the light amount of the background light is different and the main subject is properly exposed to a plurality of continuous images. apparatus.
[0011]
(4) An image pickup method characterized in that a plurality of images in which the mix ratio of the light amount of the flash light and the light amount of the background light are different and the main subject is appropriately exposed are automatically picked up continuously.
[0012]
(5) A program for realizing the imaging method according to (4).
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to examples of a camera. The present invention is not limited to the form of the apparatus, but can be implemented in the form of a method or a program for realizing the method, supported by the description of the embodiment.
[0014]
【Example】
FIG. 1 is a cross-sectional view mainly showing an arrangement of optical members in a “camera” according to an embodiment.
[0015]
FIG. 1 shows the configuration of a so-called single-lens reflex camera in which a lens is interchangeable, wherein 1 is a camera body, 2 is an interchangeable lens, and 3 is a flash device.
[0016]
In the camera body 1, reference numeral 10 denotes a mechanical shutter, reference numeral 11 denotes a low-pass filter, reference numeral 12 denotes an image sensor including an accumulation type photoelectric conversion element in an area such as CMOS or CCD, reference numeral 13 denotes a semi-transparent main mirror, and reference numeral 14 denotes a first reflection. The main mirror 13 and the first reflection mirror 14 are both mirrors that jump upward when photographing. Reference numeral 15 denotes a paraxial imaging surface conjugate to the surface of the image sensor 12 by the first reflection mirror 14, 16 denotes a second reflection mirror, 17 denotes an infrared cut filter, 18 denotes a stop having two openings, and 19 denotes a stop. A secondary imaging lens 20 is a focus detection sensor.
[0017]
The focus detecting sensor 20 is composed of an accumulation type photoelectric conversion element having an area such as a CMOS or a CCD. As shown in FIG. 2, light receiving sensor sections 20A and 20B divided into a large number corresponding to the two openings of the diaphragm 18 are provided. And two pairs of areas. Further, in addition to the light receiving sensor units 20A and 20B, a signal storage unit, a signal processing peripheral circuit, and the like are formed as an integrated circuit on the same chip.
[0018]
As described in detail in Japanese Patent Application Laid-Open No. 9-184965 and the like, the configuration from the first reflection mirror 14 to the focus detection sensor 20 is based on the focus by an image shift method at an arbitrary position in a shooting screen. This enables detection.
[0019]
Reference numeral 21 denotes a diffusing focusing plate, 22 denotes a pentaprism, 23 denotes an eyepiece, 24 denotes a third reflecting mirror, 25 denotes a condensing lens, and 26 denotes a photometric sensor for obtaining information on the brightness of the subject.
[0020]
The photometric sensor 26 is made of, for example, a photoelectric conversion element such as a silicon photodiode, and has a configuration in which a plurality of light-receiving sensors are divided in a grid as illustrated in FIG. And As shown, in this example, the inside of the light receiving visual field is divided into 7 columns × 5 rows = 35 divisions. The light receiving units divided into 35 are referred to as PD11 to PD57. It is well known that a signal amplifier, a signal processing peripheral circuit, and the like in addition to the light receiving sensor are formed as an integrated circuit on the same chip.
[0021]
The focus plate 21, the pentaprism 22, and the eyepiece 23 constitute a finder optical system. A part of the light beam reflected by the main mirror 13 and diffused by the focus plate 21 outside the optical axis enters the photometric sensor 26.
[0022]
FIG. 4 is a diagram showing a corresponding positional relationship between a focus detection position in a shooting screen by a focus detection unit such as the focus detection sensor 20 and the like and the photometric sensor 26 divided into 35 parts. In this example, the focus detection positions in the photographing screen are nine points from S01 to S23, and focus detection is performed at a position corresponding to the light receiving unit PD23 of the photometric sensor 26. Further, as shown in the figure, the focus detection position S02 performs focus detection at a position corresponding to the light receiving unit PD24 of the photometric sensor 26, and the focus detection position S03 focuses at a position corresponding to the light receiving unit PD25 of the photometric sensor 26. The focus detection is performed at the position corresponding to the light receiving portion PD45 of the photometric sensor 26 in the same manner.
[0023]
Returning to the description of FIG. Reference numeral 27 denotes a mount for mounting a photographic lens, 28 denotes a contact for performing information communication with the photographic lens, and 29 denotes a connection for mounting a flash device.
[0024]
In the interchangeable lens 2, reference numerals 30a to 30e denote optical lenses constituting a photographing lens, reference numeral 31 denotes an aperture, reference numeral 32 denotes a contact portion for performing information communication with the camera body, and reference numeral 33 denotes a mount portion for attachment to the camera.
[0025]
In the flash device 3, 34 is a xenon tube, 35 is a reflection shade, 36 is a Fresnel plate, 37 is a monitor sensor for monitoring the light emission amount of the xenon tube 34, and 38 is an attachment for attaching the flash device 3 to the camera body 1. Department.
[0026]
FIG. 5 is a block diagram showing a configuration example of an electric circuit of the camera body 1, the interchangeable lens 2 and the flash device 3 embodying the present invention. In the camera body 1, reference numeral 41 denotes a control means of a one-chip microcomputer having, for example, an ALU, a ROM, a RAM, an A / D converter, a timer, a serial communication port (SPI), and the like, and controls the entire camera mechanism and the like. . A specific control sequence of the control means 41 will be described later. The focus detection sensor 20 and the photometry sensor 26 are the same as those described in FIG. Output signals of the focus detection sensor 20 and the photometry sensor 26 are connected to an A / D converter input terminal of the control means 41.
[0027]
Reference numeral 42 denotes a shutter driving unit which is connected to an output terminal of the control unit 41 and drives the mechanical shutter 10 shown in FIG. Reference numeral 43 denotes a signal processing circuit which controls the image pickup device 12 in accordance with an instruction from the control unit 41, inputs an image pickup signal output from the image pickup device 12 while performing A / D conversion, performs signal processing, and obtains an image signal. Further, necessary image processing is performed on the obtained image signal. Reference numeral 44 denotes storage means such as a nonvolatile memory such as a flash ROM or an optical disk, and stores a captured image signal. Reference numeral 45 denotes a first motor driver, which is connected to and controlled by an output terminal of the control means 41 to perform the up / down operation of the main mirror 13 and the first reflection mirror 14. Reference numeral 47 denotes a display which is constituted by a liquid crystal panel or the like and displays the number of shots, date information, exposure information, and the like. Reference numeral 48 denotes white balance setting means for setting a white balance mode, etc., 49 denotes a photographing mode setting means, and 50 denotes a release switch. Reference numeral 28 denotes a contact portion shown in FIG. 1 to which input / output signals of a serial communication port of the control means 41 are connected. Reference numeral 29 denotes a flash device connection unit shown in FIG. 1, to which input / output signals of a serial communication port of the control unit 41 are connected so that communication with the flash device 3 is possible.
[0028]
In the interchangeable lens 2, reference numeral 51 denotes a lens control unit using a one-chip microcomputer having, for example, an ALU, a ROM, a RAM, a timer, and a serial communication port (SPI). Reference numeral 52 denotes a second motor driver, which is connected to and controlled by an output terminal of the lens control means 51 and drives a second motor 53 for performing focus adjustment. Reference numeral 54 denotes a third motor driver, which is connected to and controlled by an output terminal of the lens control means 51, and drives a third motor 55 for controlling the diaphragm 31 shown in FIG. Reference numeral 56 denotes a distance encoder for obtaining information on the extension amount of the focusing lens, that is, information on the subject distance, and is connected to the input terminal of the lens control means 51. Reference numeral 57 denotes a zoom encoder for obtaining focal length information at the time of photographing when the interchangeable lens 30 is a zoom lens, and is connected to an input terminal of the lens control means 51. Reference numeral 32 denotes a contact portion shown in FIG. 1, to which input / output signals of a serial communication port of the lens control unit 51 are connected.
[0029]
When the interchangeable lens 2 is mounted on the camera body 1, the respective contact portions 28 and 32 are connected, and the lens control means 51 can perform data communication with the control means 41 of the camera body. The lens-specific optical information necessary for the control means 41 of the camera body to perform focus detection and exposure calculation, information on the subject distance based on the distance encoder 56 or the zoom encoder 57, or the focal length information is provided by the lens control means 51. Is output to the control means 41 of the camera body by data communication. Further, as a result of the focus detection and the exposure calculation performed by the control means 41 of the camera body, the obtained focus adjustment information and aperture information are output from the control means 41 of the camera body to the lens control means 51 by data communication, and the lens The control means 51 controls the second motor driver 52 according to the focus adjustment information, and controls the third motor driver 54 according to the aperture information.
[0030]
In the flash device 3, reference numeral 61 denotes a flash control means by a one-chip microcomputer having an ALU, a ROM, a RAM, an A / D converter, a timer, a serial communication port (SPI) or the like built therein. The booster, the xenon tube 34 and the monitor sensor 37 for generating a high voltage of about 300 V necessary for light emission are the same as those shown in FIG. When the flash device 3 is mounted on the camera body 1, the respective connecting portions 38 and 29 are connected, and the flash control means 61 can perform data communication with the control means 41 of the camera body. The flash control unit 61 controls the boosting unit 62 according to the communication content from the control unit 41 of the camera main body to start or stop the light emission of the xenon tube 34, and also transmits the detection amount of the monitor sensor 37 to the control unit 41 of the camera main body. Output to
[0031]
Next, a specific operation sequence of the control unit 41 of the camera body according to the present invention will be described with reference to a flowchart starting from FIG. When the power switch (not shown) is turned on and the control means 41 becomes operable, the processing is executed from step 101 in FIG. 6 (hereinafter, the number of steps is indicated by parentheses).
[0032]
(101) The setting information is inputted by the photographing mode setting means 49, and it is checked whether or not the flash photographing mode is set. If the mode is not the flash photography mode, the process proceeds to (102).
[0033]
(102) A control signal is output to the focus detection sensor 20 to perform signal accumulation. When the accumulation is completed, A / D conversion is performed while reading out the signal accumulated in the focus detection sensor 20. Further, various necessary data correction such as shading is performed on the read digital data.
[0034]
(103) Lens information and the like necessary for focus detection are input from the lens control means 51, and the focus state of each part of the photographing screen is calculated from this and digital data obtained from the focus detection sensor 20. From the obtained focus state of each part of the photographing screen, an area to be focused in the screen is determined by a method described in, for example, JP-A-11-190816. The lens moving amount for focusing is calculated according to the focus state in the determined area, and the calculated lens moving amount is output to the lens control unit 51. In accordance with this, the lens control means 51 outputs a signal to the second motor driver 52 so as to drive the focus adjusting lens, and drives the second motor 53. As a result, the photographing lens is brought into focus with respect to the subject.
[0035]
(104) A / D conversion is performed while reading out the signals of the light receiving units PD11 to PD57 divided by 35 from the photometric sensor 26, luminance information of each part of the screen is input, and further necessary lens information and the like are input from the lens control unit 51. Then, the brightness information of each section of the input screen is corrected, and the subject brightness information of each light receiving section is obtained.
[0036]
(105) The luminance of the entire screen is calculated by weighting the luminance information of the division unit corresponding to the focus detection part from the obtained luminance information of the subject for each light receiving unit. Based on the luminance information of the entire screen calculated in this way, the storage time (i.e., shutter speed) and aperture value of the image sensor 12 that are optimal for photographing are determined from a predetermined program diagram and displayed on the display 47. When one of the shutter speed and the aperture value is preset, the other factor that provides the optimum exposure is determined in combination with the preset value.
[0037]
(106) Wait until the release switch 50 is turned on. If it is not turned on, the process returns to (101), but if it is turned on, the process proceeds to (107).
[0038]
(107) A control signal is output to the first motor driver 45 to drive the first motor 46 to flip up the main mirror 13 and the first reflection mirror 14. Subsequently, the aperture value information calculated in the step (105) is output to the lens control means 51. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture state.
[0039]
(108) A signal is output to the shutter driving unit 42 to open the shutter 10. Accordingly, light rays from the photographing lens are incident on the image pickup device 12 and imaging can be performed. The accumulation time of the image sensor 12 is set in accordance with the accumulation time calculated in the step (105), and an instruction is issued to the signal processing circuit 43 so that imaging is performed by the image sensor 12. Thereby, imaging is performed. When the imaging is completed, a signal is output to the shutter driving unit 42, and the shutter 10 is set in a light-shielding state. As a result, light rays from the imaging lens to the image sensor 12 are blocked.
[0040]
(109) Information is output to the lens control means 51 so that the aperture 31 is opened. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture open state. Further, a control signal is output to the first motor driver to drive the first motor 44 to lower the main mirror 13 and the first reflection mirror 14.
[0041]
(110) Read out the captured image information from the image sensor 12 while performing A / D conversion, and instruct the signal processing circuit 43 to perform necessary correction processing and interpolation processing.
[0042]
(111) An instruction is issued to the signal processing circuit 43 to perform white balance adjustment on the captured image information. If the white balance setting value is manually set by the white balance setting means 48, the white balance is adjusted by performing gain correction of the red channel and blue channel of the entire screen of the captured image information according to the manual setting value. If the automatic white balance adjustment mode is set by the white balance setting unit 48, one screen is divided into a plurality of pieces in the captured image information, and a white area of the subject is extracted from a color difference signal for each area. Further, based on the signal of the extracted area, gain correction of the red channel and the blue channel of the entire screen is performed to perform white balance adjustment.
[0043]
Note that the case where the white balance setting value is manually set refers to a case where color temperature information of a photographing light source is designated or a case where a light source type such as a daylight or a fluorescent lamp is designated.
[0044]
(112) An instruction is issued to the signal processing circuit 43 so that the captured image information on which the white balance adjustment has been performed is compression-converted into a recording file format and stored in the storage unit 44.
[0045]
This ends the shooting sequence in the case where the flash shooting mode is not set.
[0046]
In the step (101), the setting information by the photographing mode setting means 49 is input, and when the flash photographing mode is set, the process proceeds to (121) in FIG.
[0047]
(121) It is checked whether the setting information by the shooting mode setting means 49 is the normal flash shooting mode or the flash bracket shooting mode. If the normal flash shooting mode is set, the process proceeds to (122).
[0048]
(122) A control signal is output to the focus detection sensor 20 to perform signal accumulation. When the accumulation is completed, A / D conversion is performed while reading out the signal accumulated in the focus detection sensor 20. Further, various necessary data correction such as shading is performed on the read digital data.
[0049]
(123) Lens information and the like necessary for performing focus detection are input from the lens control unit 51 in the same manner as in the above-described step (103), and a photographing screen is obtained from the digital data obtained from the lens control unit 20. The focus state of each part is calculated. Further, an area to be focused on the screen is determined. The lens moving amount for focusing is calculated according to the focus state in the determined area, and the calculated lens moving amount is output to the lens control unit 51. In accordance with this, the lens control means 51 outputs a signal to the second motor driver 52 so as to drive the focus adjusting lens, and drives the second motor 53. As a result, the photographing lens is brought into focus with respect to the subject.
[0050]
(124) A / D conversion is performed while reading out the signals of the light receiving units PD11 to PD57 divided by 35 from the photometric sensor 26, luminance information of each part of the screen is input, and further necessary lens information and the like are input from the lens control unit 51. Then, the brightness information of each section of the input screen is corrected, and the subject brightness information of each light receiving section is obtained. The subject brightness information for each light receiving unit is called B (n). n is 11 to 57 corresponding to each light receiving unit divided into 35.
[0051]
(125) The luminance of the entire screen is calculated by weighting the luminance information of the division unit corresponding to the focus detection part from the obtained luminance information of the subject for each light receiving unit. Based on the luminance information of the entire screen calculated in this way, the storage time (i.e., shutter speed) and aperture value of the image sensor 12 that are optimal for photographing are determined from a predetermined program diagram and displayed on the display 47. When one of the shutter speed and the aperture value is preset, the other factor that provides the optimum exposure is determined in combination with the preset value. The exposure value based on the determined apex value of the shutter speed and the aperture value is called EvT.
[0052]
EvT = Tv + Av (Tv is the apex value of the shutter speed, Av is the apex value of the aperture value, the first exposure factor)
(126) Wait until the release switch 50 is turned on. If it is not turned on, the process returns to (121), but if it is turned on, the process proceeds to (127).
[0053]
(127) The flash controller 61 communicates with the flash controller 61 to instruct preliminary flash emission. As a result, the flash control means 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the xenon tube 34 emits a predetermined amount of preliminary light emission. A / D conversion is performed while reading out the signals of the light receiving units PD11 to PD57 divided into 35 by the photometric sensor 26 in order to obtain the luminance information of the subject during the preliminary light emission, and the preliminary light emission of each part of the screen is performed. Enter hourly luminance information. The pre-emission luminance information for each light receiving unit is referred to as P (n). n is 11 to 57 corresponding to each light receiving unit divided into 35.
[0054]
(128) Since the pre-flash luminance information of each part of the screen obtained in the step (127) is subject luminance information in a state where the background light for the subject and the pre-flash of the flash are added, this is used as the flash luminance information. In order to obtain the subject luminance information based on only the preliminary light emission, the subject luminance of only the background light obtained in the step (124) is obtained from the preliminary light emission luminance information obtained in the step (127) for each of the light receiving units PD11 to PD57. Subtract information. The subject luminance information based on only the preliminary flash light emission is referred to as F (n). n is 11 to 57 corresponding to each light receiving unit divided into 35.
[0055]
F (n) = P (n) -B (n)
(129) F (n) and B (n) in a region corresponding to the region in the screen focused in step (123), and main emission from preliminary emission from EvT obtained in step (125) Is calculated.
[0056]
G0 = log ₂ (EvT-B (n)) / (F (n))
Since the numerator EvT-B (n) is obtained by subtracting the luminance information of the main subject from the background light from the Ev value obtained by a combination of the shutter speed and the aperture value used for imaging, the background light is bright like a daytime synchro. Except for the case where a flash is used, if the flash light is applied to the main subject by an amount corresponding to the subtraction result, the proper exposure is obtained. Since F (n) of the denominator is luminance information based on only the flash preliminary light emission in the main subject area, G0 obtained by this equation is determined by multiplying the light emission amount of the preliminary light emission by the main light emission when the main light emission is performed. It indicates whether the proper exposure is obtained by the total light amount of the background light and the flash light.
[0057]
The main light emission amount of the flash is communicated to the flash control means 61 based on the calculated G0.
[0058]
(130) A control signal is output to the first motor driver 45 to drive the first motor 46 to flip up the main mirror 13 and the first reflection mirror 14. Subsequently, the aperture value information calculated in the step (125) is output to the lens control means 51. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture state.
[0059]
(131) A signal is output to the shutter driving means 42 to open the shutter 10. Accordingly, light rays from the photographing lens are incident on the image pickup device 12 and imaging can be performed. The accumulation time of the image sensor 12 is set in accordance with the accumulation time calculated in the step (125), and the signal processing circuit 43 is instructed to perform the image pickup by the image sensor 12. In addition, a flash emission instruction is given to the flash control means 61 in synchronization with the imaging timing. In accordance with the light emission instruction, the flash control means 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the light emission amount corresponds to G0 calculated in step (129). Thus, imaging with flash emission is performed. When the imaging is completed, a signal is output to the shutter driving unit 42, and the shutter 10 is set in a light-shielding state. As a result, light rays from the imaging lens to the image sensor 12 are blocked.
[0060]
(132) Information is output to the lens control means 51 so that the aperture 31 is opened. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture open state. Further, a control signal is output to the first motor driver 45 to drive the first motor 46 to lower the main mirror 13 and the first reflection mirror 14.
[0061]
(133) The captured image information is read from the image sensor 12 while performing A / D conversion, and an instruction is issued to the signal processing circuit 43 to perform necessary correction processing and interpolation processing.
[0062]
(134) An instruction is issued to the signal processing circuit 43 to perform white balance adjustment on the captured image information. If the white balance setting value is manually set by the white balance setting means 48, the white balance is adjusted by performing gain correction of the red channel and blue channel of the entire screen of the captured image information according to the manual setting value. If the automatic white balance adjustment mode is set by the white balance setting unit 48, one screen is divided into a plurality of pieces in the captured image information, and a white area of the subject is extracted from a color difference signal for each area. Further, based on the signal of the extracted area, gain correction of the red channel and the blue channel of the entire screen is performed to perform white balance adjustment.
[0063]
(135) An instruction is issued to the signal processing circuit 43 to compress and convert the captured image information on which the white balance adjustment has been performed into a recording file format and store it in the storage unit 44.
[0064]
This completes the shooting sequence in the normal flash shooting mode.
[0065]
If the setting information by the photographing mode setting means 49 is the flash bracket photographing mode in the step (121), the process proceeds to (151) in FIG.
[0066]
(151) A control signal is output to the focus detection sensor 20 to perform signal accumulation. When the accumulation is completed, A / D conversion is performed while reading out the signal accumulated in the focus detection sensor 20. Further, various necessary data correction such as shading is performed on the read digital data.
[0067]
(152) As in the step (103) described above, lens information and the like necessary for performing focus detection are input from the lens control unit 51, and a photographing screen is obtained based on this and digital data obtained from the focus detection sensor 20. The focus state of each part is calculated. Further, an area to be focused on the screen is determined. The lens moving amount for focusing is calculated according to the focus state in the determined area, and the calculated lens moving amount is output to the lens control unit 51. In accordance with this, the lens control means 51 outputs a signal to the second motor driver 52 so as to drive the focus adjusting lens, and drives the second motor 53. As a result, the photographing lens is brought into focus with respect to the subject.
[0068]
(153) A / D conversion is performed while reading out the signals of the light receiving units PD11 to PD57 divided by 35 from the photometric sensor 26, luminance information of each part of the screen is input, and further necessary lens information and the like are input from the lens control unit 51. Then, the brightness information of each section of the input screen is corrected, and the subject brightness information of each light receiving section is obtained. The subject brightness information for each light receiving unit is called B (n). n is 11 to 57 corresponding to each light receiving unit divided into 35.
[0069]
(154) The luminance of the entire screen is calculated by weighting the luminance information of the division unit corresponding to the focus detection part from the obtained luminance information of the subject for each light receiving unit. The storage time (ie, shutter speed) and aperture value of the image pickup device 12 that are optimal for photographing are determined from a predetermined program diagram based on the luminance information of the entire screen calculated in this manner. Is displayed on the display 47. When one of the shutter speed and the aperture value is preset, the other factor that provides the optimum exposure is determined in combination with the preset value. The exposure value based on the determined apex value of the shutter speed and the aperture value is called EvT1.
[0070]
EvT1 = Tv1 + Av1
(Tv1 and Av1 are the shutter speed and the apex value of the aperture value in the first imaging)
(155) Wait until the release switch 50 is turned on. If the switch is not turned on, the process returns to (151). If the switch is turned on, the process proceeds to (156).
[0071]
(156) The flash controller 61 communicates with the flash controller 61 to instruct preliminary flash emission. As a result, the flash control means 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the xenon tube 34 emits a predetermined amount of preliminary light emission. A / D conversion is performed while reading out the signals of the light receiving units PD11 to PD57 divided into 35 by the photometric sensor 26 in order to obtain the luminance information of the subject during the preliminary light emission, and the preliminary light emission of each part of the screen is performed. Enter hourly luminance information. The pre-emission luminance information for each light receiving unit is referred to as P (n). n is 11 to 57 corresponding to each light receiving unit divided into 35.
[0072]
(157) Since the pre-flash luminance information of each part of the screen obtained in the step (156) is subject luminance information in a state where the background light for the subject and the pre-flash of the flash are added, the luminance information of the flash is used. In order to obtain the subject luminance information only by the preliminary light emission, the subject luminance of only the background light obtained in the step (153) is obtained from the preliminary light emission luminance information obtained in the step (156) for each of the light receiving units PD11 to PD57. Subtract information. The subject luminance information based on only the preliminary flash light emission is referred to as F (n). n is 11 to 57 corresponding to each light receiving unit divided into 35.
[0073]
F (n) = P (n) -B (n)
(158) F (n) and B (n) in a region corresponding to the region in the screen focused in step (152), and main emission from preliminary emission from EvT1 obtained in step (154) Is calculated in the same manner as in step (129).
[0074]
G1 = log ₂ (EvT1-B (n)) / (F (n))
As described in the above step (129), G1 obtained by this equation is appropriate for the total light amount of the background light and the flash light, provided that the light emission amount at the time of the main light emission is several times the light amount of the preliminary light emission. Indicates whether it will be exposed. The main light emission amount of the flash is communicated to the flash control means 61 based on the calculated G1.
[0075]
(159) A control signal is output to the first motor driver 45 to drive the first motor 46 to flip up the main mirror 13 and the first reflection mirror 14. Subsequently, the aperture value information calculated in the step (154) is output to the lens control means 51. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture state.
[0076]
(160) A signal is output to the shutter driving means 42 to open the shutter 10. Accordingly, light rays from the photographing lens are incident on the image pickup device 12 and imaging can be performed. The accumulation time of the image sensor 12 is set in accordance with the accumulation time calculated in the step (154), and the signal processing circuit 43 is instructed to perform the image pickup by the image sensor 12. In addition, a flash emission instruction is given to the flash control means 61 in synchronization with the imaging timing. In accordance with the light emission instruction, the flash control means 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the light emission amount corresponds to G1 calculated in step (158). As a result, the first imaging with flash emission is performed. When the imaging is completed, a signal is output to the shutter driving unit 42, and the shutter 10 is set in a light-shielding state. As a result, light rays from the imaging lens to the image sensor 12 are blocked.
[0077]
(161) Information is output to the lens control means 51 so that the aperture 31 is opened. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture open state. Further, a control signal is output to the first motor driver 45 to drive the first motor 46 to lower the main mirror 13 and the first reflection mirror 14.
[0078]
(162) Read out the first captured image information from the image sensor 12 while performing A / D conversion, and instruct the signal processing circuit 43 to perform necessary correction processing and interpolation processing.
[0079]
(163) An instruction is issued to the signal processing circuit 43 to perform white balance adjustment on the first captured image information. If the white balance setting value is manually set by the white balance setting means 48, the white balance is adjusted by performing gain correction of the red channel and blue channel of the entire screen of the captured image information according to the manual setting value. If the automatic white balance adjustment mode is set by the white balance setting means 48, one screen is divided into a plurality of sections in the first captured image information, and a white area of the subject is extracted from a color difference signal for each area. . Further, based on the signal of the extracted area, gain correction of the red channel and the blue channel of the entire screen is performed to perform white balance adjustment. The white balance adjustment amount executed in this step is stored because it is used in a later step.
[0080]
(164) An instruction is issued to the signal processing circuit 43 so that the first captured image information on which the white balance adjustment has been performed is compression-converted into a recording file format and stored in the storage unit 44.
[0081]
(165) The exposure value based on the shutter speed and the aperture value calculated in the step (154) is reduced by a predetermined amount ΔE in the bracket shooting mode to determine the second exposure factor for imaging. ΔE may be a fixed value set in advance or a value set by a user.
[0082]
EvT2 = EvT1-ΔE
EvT2 = Tv2 + Av2
(Tv2, Av2 are the shutter speed and the apex value of the aperture value in the second imaging)
(166) The main emission gain G2 in the second imaging is calculated from the second imaging EvT2.
[0083]
G2 = log ₂ (EvT2-B (n)) / (F (n))
Since EvT2 is smaller than EvT1 by ΔE as compared with the first imaging, G2 is smaller than G1 and the flash emission amount is smaller. However, the fact that EvT2 is smaller than EvT1 by ΔE means that the shutter speed becomes slower or the aperture opens, so that the background light component at the time of imaging becomes larger. Therefore, it is possible to control to perform imaging in which the flash light component is small and the background light component is large while the exposure amount based on the sum of the flash light and the background light of the main subject remains the same appropriate value as in the first imaging. The main light emission amount of the flash is communicated to the flash control means 61 based on the calculated G2.
[0084]
(167) A control signal is output to the first motor driver 45 to drive the first motor 46 to flip up the main mirror 13 and the first reflection mirror 14. Subsequently, the aperture value information calculated in the step (165) is output to the lens control means 51. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture state.
[0085]
(168) A signal is output to the shutter drive unit 42 to open the shutter 10. Accordingly, light rays from the photographing lens are incident on the image pickup device 12 and imaging can be performed. The accumulation time of the image sensor 12 is set in accordance with the accumulation time calculated in the step (165), and an instruction is issued to the signal processing circuit 43 so that the image sensor 12 performs imaging. In addition, a flash emission instruction is given to the flash control means 61 in synchronization with the imaging timing. In accordance with the light emission instruction, the flash control means 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the light emission amount corresponds to G2 calculated in step (166). As a result, the second imaging with flash emission is performed. When the imaging is completed, a signal is output to the shutter driving unit 42, and the shutter 10 is set in a light-shielding state. As a result, light rays from the imaging lens to the image sensor 12 are blocked.
[0086]
(169) Information is output to the lens control unit 51 so that the aperture 31 is opened. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture open state. Further, a control signal is output to the first motor driver 45 to drive the first motor 45 to lower the main mirror 13 and the first reflection mirror 14.
[0087]
(170) Read out the second captured image information from the image sensor 12 while performing A / D conversion, and instruct the signal processing circuit 43 to perform necessary correction processing and interpolation processing.
[0088]
(171) An instruction is issued to the signal processing circuit 43 to perform white balance adjustment on the second captured image information. In this case, the white balance is adjusted according to the white balance adjustment amount executed in the step (163).
[0089]
(172) An instruction is issued to the signal processing circuit 43 so that the second captured image information on which the white balance adjustment has been performed is compression-converted into a recording file format and stored in the storage unit 44.
[0090]
(173) The exposure value based on the shutter speed and aperture value calculated in the step (154) is increased by a predetermined amount ΔE in the bracket photographing mode to determine the third exposure factor for imaging. ΔE may be a fixed value set in advance or a value set by the user as in the step (165).
[0091]
EvT3 = EvT1 + ΔE
EvT3 = Tv3 + Av3
(Tv3, Av3 are the shutter speed and the apex value of the aperture value in the third imaging)
(174) The main emission gain G3 in the third imaging is calculated from the third imaging EvT3.
[0092]
G3 = log ₂ (EvT3-B (n)) / (F (n))
Since EvT3 is larger than EvT1 by ΔE compared to the first imaging, G3 is larger than G1 and the flash emission amount is larger. However, the fact that EvT3 is larger than EvT1 by ΔE means that the shutter speed becomes faster or the aperture becomes narrower, so that the background light component at the time of imaging becomes smaller. Therefore, it is possible to control to perform imaging in which the flash light component is large and the background light component is small while the exposure amount based on the sum of the flash light and the background light of the main subject remains the same appropriate value as in the first imaging. The main light emission amount of the flash is communicated to the flash control means 61 based on the calculated G3.
[0093]
(175) A control signal is output to the first motor driver 45 to drive the first motor 46 to flip up the main mirror 13 and the first reflection mirror 14. Subsequently, the aperture value information calculated in the step (173) is output to the lens control means 51. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture state.
[0094]
(176) A signal is output to the shutter driving means 42 to open the shutter 10. Accordingly, light rays from the photographing lens are incident on the image pickup device 12 and imaging can be performed. The storage time of the image sensor 12 is set in accordance with the storage time calculated in the step (173), and an instruction is issued to the signal processing circuit 43 so that imaging is performed by the image sensor 12. In addition, a flash emission instruction is given to the flash control means 61 in synchronization with the imaging timing. In response to the light emission instruction, the flash control means 61 causes the xenon tube 34 to emit light based on the output signal of the monitor sensor 37 so that the light emission amount corresponds to G3 calculated in step (174). As a result, the third imaging with flash emission is performed. When the imaging is completed, a signal is output to the shutter driving unit 42, and the shutter 10 is set in a light-shielding state. As a result, light rays from the imaging lens to the image sensor 12 are blocked.
[0095]
(177) Information is output to the lens controller 51 so that the aperture 31 is opened. According to this information, the lens control unit 51 outputs a signal to the third motor driver 54 so as to drive the diaphragm 31 and drives the third motor 55. As a result, the taking lens is brought into the aperture open state. Further, a control signal is output to the first motor driver 45 to drive the first motor 46 to lower the main mirror 13 and the first reflection mirror 14.
[0096]
(178) The third captured image information is read from the image sensor 12 while performing A / D conversion, and an instruction is issued to the signal processing circuit 43 to perform necessary correction processing and interpolation processing.
[0097]
(179) An instruction is issued to the signal processing circuit 43 to perform white balance adjustment on the third captured image information. In this case, the white balance is adjusted according to the white balance adjustment amount executed in the step (163).
[0098]
(180) An instruction is issued to the signal processing circuit 43 so that the third captured image information on which the white balance adjustment has been performed is compression-converted into a recording file format and stored in the storage means 44.
[0099]
Thus, the sequence of the bracket shooting mode ends.
[0100]
As described above, according to the present embodiment, a plurality of images in which the mix ratio between the light amount of the flash (strobe) and the light amount of the background light (stationary light) is different and the main subject is properly exposed are automatically captured. Then, it is possible to select an image as intended. In addition, since the mix ratio of the light amount of the flash (strobe) and the light amount of the background light (stationary light) is automatically different and the white balance adjustment amounts of a plurality of images in which the main subject is properly exposed are set to the same value, especially the image pickup is performed. It is possible to reliably reflect the change in the color development of the image due to the difference in the mix ratio at the time of shooting under a colored light source such as tungsten light which produces an atmosphere of the image.
[0101]
In the above-described embodiment, the first balance is obtained by applying the white balance adjustment amount obtained from the first captured image information in the step (163) to the second captured image and the third captured image. , The white balance adjustment amounts for the third captured image are the same, but the white balance adjustment amount obtained from the first captured image information and the white balance adjustment amount obtained from the second The adjustment amount and the white balance adjustment amount obtained from the third captured image information are obtained, and the average value is calculated, and the same white balance adjustment amount based on the calculated average value is applied to the first to third captured images. The form of application is also conceivable.
[0102]
【The invention's effect】
As described above, according to the present invention, it is possible to automatically change the light amount of a flash (strobe) and perform image capturing a plurality of times to obtain an image as intended.
[0103]
More specifically, it is possible to automatically capture a plurality of images in which the mix ratio of the light amount of the flash (strobe) and the light amount of the background light (stationary light) is different and the main subject is properly exposed, and select an image as intended. I can do it. In addition, automatically, the white balance adjustment amounts in a plurality of images in which the mix ratio of the light amount of the flash (strobe) and the light amount of the background light (stationary light) are different and the main subject is properly exposed are the same, and particularly, It is possible to reliably reflect a change in the color development of an image due to a difference in the mix ratio when photographing under a tinted light source such as tungsten light that creates an atmosphere.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an arrangement of optical members in an embodiment.
FIG. 2 is a diagram illustrating a configuration of a focus detection sensor.
FIG. 3 is a diagram showing a configuration of a photometric sensor.
FIG. 4 is a diagram showing a focus detection position.
FIG. 5 is a block diagram showing a configuration of an electric circuit in the embodiment.
FIG. 6 is a flowchart showing the operation of the camera (part 1).
FIG. 7 is a flowchart showing the operation of the camera (part 2).
FIG. 8 is a flowchart showing the operation of the camera (part 3).
[Explanation of symbols]
1 Camera body
2 interchangeable lenses
3 Flash device
12 Image sensor
41 Camera control means
43 signal processing circuit
51 Lens control means
61 Flash device control means

Claims (1)

Background light amount determining means for determining a background light amount based on luminance information of a subject and a first exposure factor based on a predetermined program diagram or a set value;
First flash light amount determination means for determining a flash light amount for adding a main subject to an appropriate exposure by adding the background light amount at the time of imaging;
The second exposure factor is determined by subtracting a predetermined amount from the first exposure factor determined by the background light amount determination means, and is added to the background light amount based on the second exposure factor to make the main subject proper exposure. Flash light amount determining means for determining a second flash light amount for
The third exposure factor is determined by adding a predetermined amount to the first exposure factor determined by the background light amount determining means, and is added to the background light amount based on the third exposure factor to make the main subject proper exposure. Flash light amount determining means for determining a third flash light amount for
The first imaging is performed based on the first exposure factor determined by the background light intensity determination unit and the flash light intensity determined by the first flash light intensity determination unit, and the second exposure factor and the second exposure factor are determined. Control means for performing a second imaging based on a flash light amount, and controlling to perform a third imaging based on the third exposure factor and the third flash light amount;
An imaging device comprising:

Images