JP2012119805A - Photographing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that a photographic lens blocks flash light and shadow (vignetting) occurs in a photographed image when flash photographing is performed including following cases: a case in which because vignetting is determined to have occurred according to an attached lens and photographing condition, an image formation (cropping) is performed avoiding a portion affected by vignetting; and a case in which a zoom position is moved to a position at which no vignetting occurs; these resulting in forming a photographer's undesired angle, and also including one more case in which a high flash position of a camera makes it difficult for vignetting to occur, but extremely increases the size of the camera itself.SOLUTION: A photographing apparatus determines whether or not vignetting occurs in an image when emitting flash light from photographing condition information such as an attached lens, a focal distance, and an attached photoflash, and automatically performs continuous shooting when vignetting occurs. One of those in the continuous shooting is an image in which vignetting has occurred by emitting flash light, and the rest are photographed without flash emission. Image drift and discomfort can be eliminated by performing synthesis for a vignetting portion in which a brightness of an image synthesized from images photographed without flash is adjusted close to a brightness of the image photographed with flash.

Description

  The present invention relates to an imaging device such as a camera that can take a still image and a moving image that can be interchanged with a lens and can emit a flash.

  2. Description of the Related Art Conventionally, a camera with a built-in flash is known as an interchangeable lens single-lens reflex camera.

  This camera with a built-in flash has a function for displaying whether or not charging for flash emission is completed and a warning function for notifying that flash light does not reach the subject. Further, when shooting a subject by combining a camera with a built-in flash with a lens whose length changes, depending on conditions such as the subject distance, the shooting lens blocks the flash light and shadows (hereinafter referred to as vignetting) occur in the shot image. When shooting with an external flash attached to the camera, vignetting may occur in the same manner depending on conditions. Various proposals have been made for the so-called flash vignetting problem.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a method of determining the amount of flash vignetting based on the subject distance, focal length, and the like of an interchangeable lens, and warning or prohibiting flash emission when vignetting occurs.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a method of determining the state of vignetting at the time of shooting and deleting the vignetting image data corresponding to the vignetting area from the image data to create recording image data.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a method of performing an image combining process using an image obtained using a flash and an image obtained using no flash when an image with flash vignetting is obtained.

Japanese Patent Laid-Open No. 4-355736 JP 2006-41741 A JP 2005-323142 A

  In general, in order to reduce vignetting, it is necessary to raise the position of the camera built-in flash and shorten the total lens length. However, increasing the position of the built-in flash is not preferable because it leads to an increase in the size of the camera. In addition, shortening the total lens length also leads to degradation of optical performance, making it difficult to obtain high-performance, high-quality photographic images that are required recently.

  The technique of Patent Document 1 performs a warning or prohibits flash emission when it is determined that vignetting occurs. This is a choice between obtaining an image in which vignetting occurs by emitting a flash or giving up shooting with the flash, and does not eliminate vignetting itself.

  There are a technique for deleting vignetting area image data and a technique for moving the lens zoom position to a position where vignetting does not occur by flash. However, these images may be different from the angle of view desired by the photographer.

  In the technique of Patent Document 3, since the brightness of an image captured with a flash use image and a flash non-use image is different, there is a possibility that an uncomfortable image may be formed at the boundary between the flash use image and the flash non-use image when combined. .

  An object of the present invention is to obtain a high-quality image by preventing vignetting at an angle desired by a photographer without changing the dimensions of a conventional camera or lens.

In order to achieve the above object, in the first invention according to the present invention,
An electronic imaging device (B) configured to be detachable from a lens device (A) including a photographing optical system, and a built-in flash device (C), or a flash device (D) configured to be detachable Get flash information to get (S9)
Lens discrimination means (10) for discriminating the lens type of the lens device
Mounted lens information holding means (16) for holding data of the lens device in the imaging device
Mounted lens focal length detection means (3)
Metering unit for measuring the brightness of the subject (17)
In what comprises
It is determined that vignetting occurs in the vignetting determination unit, including a vignetting determination unit that determines vignetting due to flash emission by calculation from the lens determination unit (10), the flash information acquisition unit (20), and the lens information holding unit (16). In such a case, at least two or more images are acquired continuously (S15 / S16),
The first image obtained by the image acquisition and the second image have different shooting conditions, and an image obtained by combining (S17) an image including at least a vignetting part of the first second image is obtained. To do.

In the second invention according to the present invention,
In the imaging device according to the first invention,
When acquiring at least two images in succession, the first image is acquired by emitting a flash (S14), and the second image is acquired without emitting the flash (S15). And

In the third invention according to the present invention,
In the imaging device according to the first invention and the second invention,
In the imaging device according to claim 1 and claim 2,
The photographing condition is a setting of ISO sensitivity.

In the fourth invention according to the present invention,
In the imaging device according to the first invention and the second invention,
The shooting condition is a setting of the number of continuous shots of the second image.

In the fifth invention according to the present invention,
In the imaging device according to the first invention and the second invention,
The photographing condition is an exposure time setting.

In the sixth invention according to the present invention,
In the imaging device according to the first invention and the second invention,
The photographing conditions are setting of exposure time, ISO sensitivity, and number of continuous shots.

In a seventh invention according to the present invention,
In the imaging device according to the first invention and the second invention,
A first image, a second image, an image obtained by combining at least one second image, and a composite image of the first and second images are all stored in a recording medium.

In an eighth invention according to the present invention,
In the imaging device according to the first invention and the second invention,
A first imaging condition in which a first image is a first image taken and a second image is a plurality of second and subsequent images;
A second imaging condition in which the first image is a final image of a plurality of images, and the second image is a plurality of images from the first image to the image one image before the final image;
The photographer can select the first photographing condition and the second photographing condition.

According to the present invention, it is possible to obtain an image in which no vignetting occurs due to flash emission by combining an image shot with flash emission and a plurality of images shot without flash emission. By combining a plurality of composite images taken without flash emission with an image taken by flash emission and bringing the brightness close, it is possible to obtain an image that does not cause a sense of incongruity in the composite portion.
It is possible to capture the image at the timing intended by the photographer by acquiring the image by flash firing in the first continuous shooting and combining multiple images without flashing in the second and subsequent images It is.

  In addition, the flash is fired at the final image of continuous shooting, and the flash firing timing is captured to the photographer by combining multiple images without flashing from the first image to the image one image before the final image. It is possible to inform the end timing.

1 is a block diagram of an imaging system in an embodiment to which the present invention is applied. 5 is a flowchart illustrating an operation of imaging control according to the first exemplary embodiment of the present invention. 6 is a flowchart illustrating an operation of shooting control in Embodiment 2 of the present invention. 1 shows a conceptual diagram of image composition in Embodiment 1 of the present invention. FIG. The conceptual diagram of the image composition in Example 2 of the present invention is shown.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[Example 1]
FIG. 1 is a block diagram illustrating a configuration of an imaging system according to an embodiment.

  In the figure, A is a lens unit (also referred to as an interchangeable lens) that is a lens device, B is a camera unit (also referred to as a camera body) that is an imaging device, C is a built-in flash unit (also referred to as a built-in flash), and D is an external flash unit. (Also called external flash). Reference numeral 1 denotes an imaging optical system, which is a fixed lens group 1a, 1c, a lens group (hereinafter referred to as a zoom group) 1b having a zooming function, a lens group (hereinafter referred to as a focus group) 1d having a focusing function, and an aperture amount. It is comprised by the aperture_diaphragm | restriction 2 for adjusting.

  The lens unit A has a built-in lens microcomputer 10. The camera unit 20 communicates with the lens unit through the communication contacts 8 and 9 from the camera microcomputer 20 of the camera unit B, and the focus drive unit 7 and the aperture stop according to the command value. The operation and control of the drive unit 5 are performed.

  The focal length detection means 3 is provided with a brush portion for position detection on a lens frame (not shown) of the zoom group 1b. On the substrate on which a variable resistor or a gray code pattern is printed as the zoom lens moves. The brush slides. By taking this output with the zoom encoder circuit, the focal length is detected and the information is taken into the lens microcomputer 10.

  The aperture of the aperture 2 is detected by the aperture sensor 4 and the current aperture is input to the lens microcomputer 10. Further, a desired opening amount is transmitted from the lens microcomputer 10 to the diaphragm driving unit 5 and the opening amount is adjusted by moving the diaphragm blades.

  The focus group 1d is driven by the focus drive unit 7, and the focus position detection means 6 can detect the position by taking the number of pulses applied to the focus drive unit into the lens microcomputer 10 by a detector (not shown).

  Actually, each lens group is composed of a plurality of lenses, but the number of lenses in each lens group is not particularly limited. Further, the configuration is not particularly limited as long as it is a single-focus configuration without a zooming mechanism, or a lens for forming an image even with a lens configuration without a focus function.

  Reference numeral 11 denotes an image sensor such as a CMOS or CCD that forms a light beam from a subject. The image of the subject image is photoelectrically converted by the image sensor 11 and output as a video signal, which is supplied to a camera process circuit (not shown). The In the case of Contrast AF, the video signal is supplied to the high-frequency component extraction circuit 12 and detected as a focus voltage based on the signal component based on the level of the high-frequency component in the video signal or the sharpness of the edge of the image, etc. And is taken into the camera microcomputer 20.

  The video signal captured from the image sensor 11 is transmitted to the display control unit 13 through the camera microcomputer 20, converted into a luminance signal and a color difference signal, subjected to processing such as gamma correction, and then displayed on the external monitor 14 at the same time. Recorded in the recording means 15. By supplying the image signal output from the image sensor 11, image data is periodically written to the recording means 15 and displayed on the external monitor 14 in real time. Although the image output means is an external monitor this time, an optical viewfinder may be used.

  The camera unit B has various lens data 16 in advance on a recording medium (not shown), identifies the type of lens through communication between the lens unit A and the camera unit B, and sends the lens data 16 of the attached lens to the camera microcomputer 20. take in. The camera microcomputer 20 compares the lens focal length 3, aperture sensor 4 and focus position 6 information obtained through the lens microcomputer 10 with information on the mounted flash captured in the camera and the lens data 16 to determine vignetting. The position to be calculated is calculated.

  Here, the vignetting determination method and the vignetting position calculation method in the present invention will be specifically described. When the type, focal length, and focus position of the lens unit A are determined, the lens extension amount and the subject distance are determined. The aperture is determined by the lens extension amount and the type of the lens unit A, and the outer diameter of the lens unit A is determined. Further, the position of the light emitting unit is determined from the type of the flash unit according to the mounting accessory information. An area where vignetting of the captured image occurs can be calculated based on the position of the light emitting unit, the outer diameter of the lens unit A, and the subject position. In this way, the lens data 16 can be created in advance by experiments or simulations in which the vignetting condition parameters are changed.

  In the camera unit B, there are a photometry unit 17 and a release button 18. When the release button 18 is pushed to a first push-in position (hereinafter referred to as SW1) at which photometry / ranging is started, the camera microcomputer 20, the lens microcomputer 10 and the focus driving unit 7 are synchronized by a known phase difference method. Focus on the subject. At the same time, the lens focal length 3, aperture sensor 4, and focus position 6 are transmitted from the lens microcomputer 10 to the camera microcomputer 20. The photometric unit 17 measures the luminance of the subject and transmits the photometric value to the camera microcomputer 20, thereby determining the aperture value, exposure time, and ISO sensitivity. The camera microcomputer 20 checks the type of the attached accessory through the communication terminal 30 and determines whether to perform flash emission based on the photometric value. When flash emission is necessary, if the external flash unit D is mounted, the external flash is emitted. When the external flash unit D is not attached, the built-in flash unit C is driven to a predetermined position to emit light. The light emission control unit 19 is a circuit that controls the light emission of the light emitting unit 21. The light emission control unit 19 is controlled by the camera microcomputer 20 and controls the presence / absence of flash light emission, light emission timing, charging of a light emitting capacitor (not shown), and the like. The light emission control unit 19 causes the light emitting unit 21 to emit light by flowing the charge accumulated in the light emitting capacitor through a xenon tube (not shown).

  Next, the control operation on the camera side in the present invention will be described step by step according to the flowchart shown in FIG.

  <S1> With the camera powered on, the camera microcomputer 20 acquires lens information through the contact portions 8 and 9 and the lens microcomputer 10, and specifies the lens data 16 on the camera side.

  <S2> The camera microcomputer 20 enters a shooting standby state and proceeds to S3.

  <S3> It is determined whether or not SW1 of the release button 18 has been pressed. If it has been pressed, the process proceeds to S4, and if not, the process proceeds to S2.

  <S4> The camera microcomputer 20 acquires the lens focal length through the contact portions 8 and 9, the lens microcomputer 10, and the focal length detection means 3, and proceeds to S5.

  <S5> An autofocus operation is performed by a known phase difference detection method. The camera microcomputer 20 drives the focus drive unit 7 through the contact portions 8 and 9 and the lens microcomputer 10 for the calculated focus position, adjusts the focus, and proceeds to S5. Although the phase difference detection method is used here, a contrast AF method may be used.

  <S6> The camera microcomputer 20 acquires the focus position through the contact portions 8 and 9, the lens microcomputer 10, and the focus position detection means 6, and proceeds to S7.

  <S7> The luminance of the subject is measured by the photometric unit 17, the photometric value is acquired, and the process proceeds to S8.

  <S8> Based on the photometric value obtained in S7, it is determined whether flash emission is necessary. If flash emission is necessary, the process proceeds to S9, and if not, the process proceeds to S11.

  <S9> The type of the attached flash is checked through the communication terminal 30, and the process proceeds to S10. If an external flash is attached, the type and data of the attached flash are acquired. If there is no external flash, the internal flash data is acquired.

  <S10> The focal length / focus position / flash data obtained in S4, S6, and S9 are compared with the lens data 16 to determine whether or not vignetting occurs. If vignetting does not occur, the process proceeds to S11. If vignetting occurs, the process proceeds to S13.

  <S11> It is determined whether or not the release button 18 has been pushed to a second push-in position (hereinafter referred to as SW2) at which exposure starts. If it has been pushed, the process proceeds to S12, and if not, the process proceeds to S4. Here, it is assumed that the autofocus is always tracked. However, when the autofocus position is fixed when SW1 is pressed, if SW2 is not pressed, the process waits until SW2 is pressed.

  <S12> The aperture amount and the exposure time are calculated based on the photometric value acquired in S7. Based on the calculated value, the aperture drive unit 5 is driven through the contact units 8 and 9, exposure is performed for a predetermined exposure time, an image is acquired, the image is stored in the recording means 15, and a shooting standby state is entered.

  <S13> Based on the photometric value acquired in S7 and the attached flash information acquired in S9, the optimum luminance is calculated, the luminance value of the subject when the flash is emitted is determined, and the process proceeds to S14.

  <S14> It is determined whether or not the SW2 of the release button 18 has been pressed. If it has been pressed, the process proceeds to S15, and if not, the process proceeds to S4. Here, it is assumed that the autofocus is always tracked. However, when the autofocus position is fixed when SW1 is pressed, if SW2 is not pressed, the process waits until SW2 is pressed.

  <S15> Based on the brightness value, aperture amount, exposure time, etc. acquired in S12, flash light emission is performed for exposure. The camera microcomputer 20 drives the aperture drive unit 5 through the contact units 8 and 9 based on the calculated value, performs exposure for a predetermined exposure time, and proceeds to S16.

  <S16> Based on the brightness value, aperture amount, exposure time, etc. acquired in S13, the ISO sensitivity value is set high so as to approach the brightness value when the flash is emitted even when the flash is not emitted, and the process proceeds to S17. Transition.

  <S17> Exposure is performed without flash emission at the ISO sensitivity set in S16, and the process proceeds to S17.

  <S18> The vignetting image obtained in S15 and the vignetting-free image obtained in S17 are synthesized, and an image obtained by synthesizing the portion where the vignetting has occurred by the flash is obtained by the method described later, and the recording means 15 To save the image and exit.

  Next, an image composition method according to the present invention will be described with reference to FIG.

  Based on the photometric value obtained in S7, the ISO sensitivity is calculated in S13 so that the luminance at the time of flash emission approaches the luminance at the time of no flash emission. FIG. 4A shows an image taken with flash emission. The portion K in the figure is vignetting. Here, as an example, it is assumed that FIG. 4A is set to the full aperture (F2.8) ISO sensitivity 200. In the case where the brightness of the subject is measured in S7 and shooting is performed without flash emission, it is assumed that the ISO sensitivity 3200 is calculated in S13 in order to perform exposure at a brightness close to that in flash emission. FIG. 4B is an image taken with ISO sensitivity 3200. FIG.

  As described above, when exposure is performed with a higher ISO sensitivity, noise in the image due to gain increase increases, but a luminance image close to that at the time of flash emission can be obtained even with a short exposure time. FIG. 4C is obtained by adding coordinates (L frame) at which the image is vignetted in step S9 to the image of FIG. 4B. The image shown in FIG. 4D without vignetting can be obtained by replacing the L frame and the image taken by flash emission with the K portion in FIG. 4A.

  As in this embodiment, the second image is continuously shot with high ISO sensitivity without flash emission, and is combined with the flash image to minimize the effects of camera shake and other effects on the first and second images. The image without vignetting can be acquired.

  In this embodiment, the K portion image in FIG. 4 (a) and the L portion image in FIG. 4 (c) are replaced. However, the high ISO sensitivity image in FIG. May be recorded in the recording means 15. 4A, 4B, and 4D may be recorded in the recording unit 15 so that the photographer can select a desired image after shooting.

[Example 2]
This embodiment has the same block diagram as that of the first embodiment. Therefore, the description similar to Example 1 is omitted.
The control operation on the camera side in the present invention will be described according to the flowchart shown in FIG. Here, S1 to S12 are the same as those in the first embodiment, and will be omitted.

  <S20> Based on the photometric value acquired in S7 and the attached flash information acquired in S9, the optimum luminance at the time of flash emission is calculated. Next, at least two or more images taken without flash firing are shot continuously (continuous shooting), combined, and the optimum number of shots, ISO, is set when the brightness setting is close to the brightness at the time of flash firing. Calculate sensitivity and exposure time.

  <S21> It is determined whether or not the SW2 of the release button 18 has been pressed. If it has been pressed, the process proceeds to S22, and if not, the process proceeds to S4. Here, it is assumed that the autofocus is always tracked. However, when the autofocus position is fixed when SW1 is pressed, if SW2 is not pressed, the process waits until SW2 is pressed.

  <S22> Based on the brightness value acquired in S20, the number of shots, the exposure time, etc., the flash is emitted to perform exposure for a predetermined exposure time, and the process proceeds to S23.

  <S23> Based on the brightness value, number of shots taken, ISO sensitivity, exposure time, etc. acquired in S20, continuous shooting is performed without flash emission, and the process proceeds to S24.

  <S24> The vignetting image obtained in S22 and the vignetting-free image obtained in S23 are combined, and the image without the vignetting portion is stored by the recording means 15 and the process ends.

  Next, an image composition method according to the present invention will be described with reference to FIG.

  Based on the photometric value obtained in S7, the exposure time is divided into a plurality of short exposure times in S20, and continuous shooting is repeated for the number divided in S23. FIG. 5A is an image taken with flash emission. The portion K in the figure is vignetting. Here, as an example, it is assumed that FIG. 5A is set to the full aperture (F2.8) ISO sensitivity 200. When the subject brightness is metered in S7 and shooting is performed without flash emission, the aperture is open (F2.8), shutter exposure time 1/8, ISO sensitivity 1600 and S20 are calculated for exposure at a brightness close to that of flash emission. Suppose that However, when the ISO sensitivity is 1600, noise is generated in the image. Therefore, eight images with ISO 200 and shutter exposure time 1/8 as shown in FIG. 5B are taken.

  If the exposure time is divided in such a short time, each image is underexposed. However, after shooting, a plurality of images are combined to form a single image as shown in FIG. 5C. Improvements can be made. FIG. 5 (d) is obtained by adding coordinates (L frame) at which the image is vignetted in step S10 to the image of FIG. 5 (c). The image shown in FIG. 5E without vignetting can be obtained by replacing the L frame and the image taken by flash emission with the K portion in FIG. 5A.

  When the gain of the entire image is increased by synthesizing many images as in this embodiment, the noise of each image is averaged, so that an image with a large SN ratio can be obtained, and the noise is suppressed. Exposure can be optimized.

  In this embodiment, the image of the K portion in FIG. 5A and the image of the L portion in FIG. 5D are replaced, but a plurality of continuous shot images in FIG. 5C are combined into one. The image may be recorded in the recording means 15 as an image free from vignetting caused by the flash. 5A, 5C, and 5E may be recorded in the recording unit 15 so that the photographer can select a desired image after shooting.

  In the present embodiment, the case where the flash photography is performed first and then the photography without flash is described, but the flash photography may be performed last. In that case, in the flowchart 2 of the first embodiment, S15 follows S17. Further, in the flowchart of FIG. 3 in the second embodiment, S22 follows S23.

  Although this embodiment is applied to a general digital single-lens reflex camera, the present embodiment is not limited to this and can be applied to a camera having a photographing function of an interchangeable lens imaging system.

1: Optical system 2: Aperture 3: Focal length detection means 4: Aperture sensor 5: Aperture drive unit 6: Focus position 7: Focus drive unit 8: Lens side contact 9: Camera side contact 10: Lens microcomputer 11: Image sensor 12 : High frequency component extraction circuit 13: Display control unit 14: Liquid crystal monitor 15: Recording means 16: Lens data 17: Photometry unit 18: Release button 19: Light emission control unit 20: Camera microcomputer 21: Light emission unit 30: Communication terminal 31: Light emission Control unit 32: light emitting unit

Claims (8)

An imaging device (B) configured to be detachable from a lens device (A) including a photographing optical system, and a built-in flash device (C), or a flash device (D) configured to be detachable Acquire flash information to be acquired (S9),
Lens discriminating means (10) for discriminating the lens type of the lens device;
Wearing lens information holding means (16) for holding data of the lens device in the imaging device;
A focal length detection means (3) of the mounted lens;
A photometric unit (17) for measuring the luminance of the subject;
In an imaging apparatus comprising:
The lens discriminating means (10), the flash information acquiring means (20), and a vignetting determining unit for determining vignetting by flash emission from the lens information holding means (16).
If the vignetting determination unit determines that vignetting occurs, continuously obtain at least two images (S15 / S16),
The first image obtained by the image acquisition and the second image have different shooting conditions, and an image obtained by combining (S17) an image including at least a vignetting part of the first second image is obtained. An imaging device.   When acquiring at least two images in succession, the first image is acquired by emitting a flash (S14), and the second image is acquired without emitting the flash (S15). The imaging apparatus according to claim 1. The imaging apparatus according to claim 1, wherein the photographing condition is setting of ISO sensitivity. The imaging apparatus according to claim 1, wherein the photographing condition is a setting of the number of continuous shots of the second image. The imaging apparatus according to claim 1, wherein the photographing condition is setting of an exposure time. The imaging apparatus according to claim 1, wherein the photographing condition is setting of an exposure time, ISO sensitivity, and the number of continuous shots. The first image, the second image, an image obtained by synthesizing at least one or more second images, and a synthesized image of the first and second images are all stored in a recording medium. The imaging device according to claim 1 or 2. A first imaging condition in which a first image is a first image taken and a second image is a plurality of second and subsequent images;
A second imaging condition in which the first image is a final image of a plurality of images, and the second image is a plurality of images from the first image to the image one image before the final image;
The imaging apparatus according to claim 1, wherein a photographer can select the first imaging condition and the second imaging condition.