JP5596959B2 - Imaging apparatus and control method thereof - Google Patents

Description

  The present invention relates to an imaging apparatus that performs non-flash emission shooting and flash emission shooting in one shooting operation.

  In recent years, a digital camera is equipped with a strobe as a standard, and in a situation where the brightness of the subject is insufficient, the subject can be photographed with an appropriate exposure by flash emission. However, depending on the shooting situation, such as backlighting or dusk, there are scenes where it is difficult to determine which of the flash photography and the non-flash photography is appropriate. To deal with this problem, some conventional digital cameras perform non-flash photography and flash photography continuously in a single release operation (shooting operation). Some images are acquired one by one (for example, see Patent Document 1).

  In addition, after taking a series of non-flash photography and flash photography with a single release operation, a review display is displayed so that the two acquired images can be compared, and the user can select a preferred image. (For example, refer to Patent Document 2).

JP 2004-54231 A JP 2007-256907 A

  However, in Patent Document 1 and Patent Document 2 described above, shooting is sequentially performed sequentially with an exposure time appropriate for both or both of strobe non-flash shooting and strobe flash shooting. For this reason, in scenes where the brightness of the subject is low, the exposure time for each shooting becomes longer, and the elapsed time from the start of the first shooting to the start of the next shooting becomes longer. There is a problem that this difference is likely to occur.

  The present invention has been made in view of the above-described problems, and the subject environment of a light-emitting photographed image and a non-light-emitting photographed image when performing light-emitting photography and non-light-emitting photography in which a light emitting unit emits light by one photographing operation. An object of the present invention is to make it possible to reduce image differences due to changes in the image quality.

In order to solve the above-described problem, an imaging apparatus according to the present invention is an imaging apparatus capable of performing a plurality of times of light emission photography and non-light emission photography in which a light emitting unit emits light in one photographing operation, Determination for determining an exposure time of the imaging means for each of the light emission photography and the non-light emission photography based on an image pickup means for picking up an image of the subject, a photometry means for photometry of the subject, and a photometric result of the photometry means And the image synthesizing means for generating a composite image by synthesizing a plurality of images obtained by the imaging means with the exposure time determined by the determining means, and all the flash photography is completed in one photographing operation. The control means for controlling to perform at least one non-flash photography before, and the light emission amounts of the plurality of flash photography performed by one photographing operation are equal, and the flash photography is performed a plurality of times. As the total emission amount becomes the target amount of light determined on the basis of the photometry result of the photometry means, a plurality of times than the light emitting time required to said target light emission amount in one light emission of the flash shooting A light emission control means for causing the light emission means to emit light by extending a total light emission time, and the image composition means is a composite image obtained by compositing a plurality of images obtained by the light emission photography in one photographing operation. And a synthesized image obtained by synthesizing a plurality of images obtained by the non-flash photography.

  According to the present invention, it is possible to reduce an image difference due to a change in a subject environment between a light-emitting photographed image and a non-light-emitting photographed image when performing light-emitting photographing and non-light-emitting photographing in which a light emitting unit emits light by one photographing operation. The purpose is to do so.

It is a block diagram which shows the structure of the digital camera which concerns on the Example of this invention. FIG. 6 is a diagram illustrating a flowchart of a shooting operation in a special continuous shooting mode according to the first and second embodiments. It is a figure which shows the flowchart of exposure condition determination in the special continuous imaging | photography mode which concerns on the Example of this invention. It is a figure which shows the flowchart of the continuous imaging | photography in the special continuous imaging | photography mode which concerns on Example 1 and Example 2. FIG. 6 is a flowchart of image composition in a special continuous shooting mode according to the first embodiment. It is a program diagram of the digital camera which concerns on the Example of this invention. It is a figure which shows the table of the light emission time with respect to the imaging | photography frequency | count of a guide number and light emission photography. It is a conceptual diagram about the light emission characteristic of LED strobe by a strobe light emission control signal. It is a conceptual diagram about the light emission characteristic of a xenon tube strobe by a strobe light emission control signal. It is the conceptual diagram which showed the relationship between the exposure time of each imaging | photography, strobe light emission time, and the imaging | photography period required for continuous imaging | photography. FIG. 3 is a conceptual diagram illustrating a state in which a composite image is generated from unit images acquired by continuous shooting in the first embodiment. It is the conceptual diagram which showed a mode that a synthesized image was produced | generated from the unit image acquired by continuous imaging | photography in Example 2 and Example 3. FIG. It is a figure explaining the example of the image composition method. It is a figure which shows the flowchart of the image alignment process and image composition in the special continuous imaging | photography mode which concerns on Example 2 and Example 3. FIG. It is a figure explaining the example of the method of detecting a motion vector. FIG. 9 is a flowchart illustrating a shooting operation in a special continuous shooting mode according to the third embodiment. FIG. 10 is a diagram illustrating a flowchart of continuous shooting in a special continuous shooting mode according to the third embodiment.

(Example 1)
Hereinafter, a digital camera as an imaging apparatus according to Embodiment 1 of the present invention will be described. FIG. 1A is a block diagram illustrating a configuration of a digital camera 100 according to the present embodiment. In FIG. 1A, 10 is a photographic lens, 12 is a shutter having a diaphragm function, and 14 is an image pickup unit including a CCD, a CMOS element, or the like that converts an optical image of a captured subject into an electric signal. Reference numeral 16 denotes an A / D converter that converts an analog signal output from the imaging unit 14 into a digital signal.

  A timing generation unit 20 supplies a clock signal and a control signal to the imaging unit 14, the A / D converter 16, and the D / A converter 28, and is controlled by the memory control unit 24 and the system control unit 50.

  An image processing unit 22 performs resizing processing and color conversion processing such as predetermined pixel interpolation and reduction on the image data from the A / D converter 16 or the image data from the memory control unit 24. The image processing unit 22 also performs predetermined calculation processing using the captured image data, and the system control unit 50 performs distance measurement control based on the obtained calculation result, so that a TTL (through-the-lens) is obtained. ) Method AF (autofocus) processing is performed. The image processing unit 22 further performs predetermined calculation processing using the captured image data, and also performs TTL AWB (auto white balance) processing based on the obtained calculation result.

  Reference numeral 28 denotes a D / A converter, and 30 denotes a display unit including an LCD or the like. Reference numeral 32 denotes a memory for storing captured still images and moving images. The image data output from the A / D converter 16 is written into the memory 32 via the image processing unit 22 and the memory control unit 24 or directly via the memory control unit 24. The memory 32 has a storage capacity sufficient to store a predetermined number of still images, a moving image and sound for a predetermined time. Thereby, even in the case of continuous shooting in which a plurality of still images are continuously shot, a large amount of image writing can be performed on the memory 32 at high speed. The memory 32 can also be used as a work area for the system control unit 50. The memory 32 is also used as a write buffer for the recording medium 200. Further, the memory 32 also serves as an image display memory, and the display image data written in the memory 32 is displayed on the display unit 30 via the D / A converter 28. If the captured image data is sequentially displayed using the display unit 30, an electronic viewfinder function (through display) can be realized.

  A compression / decompression unit 34 compresses and decompresses image data by adaptive discrete cosine transform (ADCT) or the like, reads a captured image stored in the memory 32, performs compression processing, and stores the processed image data in the memory 32. Write to. In addition, the compressed image read from the recording medium 200 or the like is read into the memory 32 and decompressed, and the processed image data is written into the memory 32. The image data written to the memory 32 by the compression / decompression unit 34 is filed in the file unit of the system control unit 50 and recorded on the recording medium 200 via the interface 90.

  Reference numeral 40 denotes an exposure control unit, and reference numeral 45 denotes a strobe as a light emitting means. In this embodiment, the strobe 45 is an LED strobe using an LED (Light Emitting Diode). The strobe 45 emits light according to a control signal from the system control unit 50. The exposure control unit 40 performs AE (automatic exposure) processing and strobe light control processing according to the control of the system control unit 50.

  Reference numeral 42 denotes an image composition unit that composites a plurality of unit images acquired by continuous shooting to generate a composite image. Reference numeral 50 denotes a system control unit that controls the entire digital camera 100. 58 is an electrically erasable / recordable non-volatile memory, such as an EEPROM. Stores constants, programs, and the like for operation of the system control unit 50. A system memory 52 expands constants and variables for operation of the system control unit 50, programs read from the nonvolatile memory 58, and the like. Here, the program is a program for executing various flowcharts in each embodiment described later.

  Reference numeral 60 denotes a mode switch that can switch the operation mode of the digital camera 100 to any one of a still image shooting mode, a continuous shooting (continuous shooting) mode, a moving image shooting mode, a playback mode, and the like. The continuous shooting mode includes a normal continuous shooting mode and a special continuous shooting mode, and one of them can be selected. Note that the normal continuous shooting mode refers to a plurality of ones of a flash shooting that performs a still image shooting by firing the flash 45 in one shooting operation and a non-flash shooting that performs a still image shooting without firing the flash 45. This mode is performed continuously. On the other hand, the special continuous shooting mode is a mode in which flash shooting and non-flash shooting are alternately performed a plurality of times in one shooting operation.

  62 denotes a first shutter switch SW1, and 64 denotes a second shutter switch SW2. The first shutter switch SW1 (62) instructs the start of operations such as AF (autofocus) processing and AE (automatic exposure) processing.

  First, the second shutter switch SW2 (64) instructs the start of operations such as AWB (auto white balance) processing and light control (pre-emission) processing. Subsequently, an instruction to start an exposure process for writing the image data into the memory 32 via the A / D converter 16 and the memory control unit 24 is given to the signal read from the imaging unit 14. At the same time, a series of development processing using computations in the image processing unit 22 and the memory control unit 24, recording processing for reading the image data from the memory 32, compression in the compression / decompression unit 34, and writing the image data in the recording medium 200. Instructs the start of the operation of In addition, in the case of moving image shooting, the start / stop of moving image shooting is instructed. Note that the user operation for switching the state of the second shutter switch SW2 (64) from the OFF state to the ON state is referred to as a photographing operation.

  Reference numeral 70 denotes an operation unit for inputting various operation instructions to the system control unit 50. Each operation member of the operation unit 70 is appropriately assigned a function for each scene by selecting and operating various function icons displayed on the display unit 30 and acts as various function buttons. Examples of the function buttons include an end button, a return button, an image advance button, a jump button, a narrowing button, and an attribute change button. For example, when the menu button is pressed, a menu screen on which various settings can be made is displayed on the display unit 30. The user can make various settings intuitively by using the menu screen displayed on the display unit 30, the four-way key, and the SET button.

  Reference numeral 72 denotes a power control switch for switching power on and power off. Reference numeral 74 denotes a power supply control unit that includes a battery detection circuit, a DC-DC converter, a switch circuit that switches a block to be energized, and the like, and detects whether or not a battery is mounted, the type of battery, and the remaining battery level. Further, the DC-DC converter is controlled based on the detection result and the instruction of the system control unit 50, and a necessary voltage is supplied to each unit including the recording medium 200 for a necessary period.

  A power source 86 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, an AC adapter, or the like. Reference numerals 82 and 84 denote connectors for connecting the power supply unit 86 and the power supply control unit 74.

  Reference numeral 90 denotes an interface with the recording medium 200 such as a memory card or a hard disk, and reference numeral 92 denotes a connector for connecting the recording medium 200 to the interface 90.

  Reference numeral 200 denotes a recording medium such as a memory card or a hard disk. The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, or the like, an interface 204 with the digital camera 100, and a connector 206 for connecting the recording medium 200 and the digital camera 100.

  FIG. 2 shows a flowchart of the shooting operation in the special continuous shooting mode of the present embodiment. Hereinafter, the shooting operation of the digital camera 100 in the special continuous shooting mode will be described with reference to FIG.

  When the power is turned on by the power control switch 72 of the digital camera 100 (S201) and the special continuous shooting mode is set by the mode switch 60 (Yes in S202), the image data from the imaging unit 14 is sequentially displayed on the display unit 30. Through display is performed (S204). In step S202, when another mode, for example, a still image shooting mode, a moving image shooting mode, a playback mode, or the like is set (No in S202), processing of each set mode is performed (S203).

  When the switch SW1 (62) of the release switch is turned on after step S204 (Yes in S205), the system control unit 50 performs a distance measurement process and focuses the photographing lens 10 on the subject based on the distance measurement result (step S204). S206).

Subsequently, the system control unit 50 performs photometry processing. The photometric process will be described below. First, the system control unit 50 performs photometry, and acquires the subject luminance value Bv from the photometry result. The exposure conditions of the photographing sensitivity Sv, the exposure time Tv, and the aperture value Av are determined according to the following formula (Formula 1) so that an appropriate exposure value Ev can be obtained from the acquired subject luminance value Bv.
Ev = Bv + Sv = Tv + Av (Formula 1)
Here, the subject luminance value Bv, the photographing sensitivity Sv, the exposure time Tv, and the aperture value Av are values expressed in APEX.

  In the present embodiment, the memory 32 stores a program diagram for non-flash photography as shown in FIG. The system control unit 50 determines the exposure conditions of the photographing sensitivity Sv_1, the exposure time Tv_1, and the aperture value Av_1 from which the appropriate exposure is obtained in the non-light-emitting photographing from the acquired subject luminance value Bv according to the non-light-emitting photographing program diagram. (S207). In FIG. 6A, when the exposure value Ev is Ev10, the exposure time Tv_1 is determined as Tv6 and the aperture value Av_1 is determined as Av4 from the position A in the figure.

  Subsequently, the system control unit 50 follows the program diagram for flash photography shown in FIG. 6B stored in the memory 32, so that the photographing sensitivity Sv_2, the exposure time Tv_2, and the aperture value at which proper exposure is obtained in the flash photography. Av_2 exposure conditions are determined and recorded in the memory 32 (S208). In FIG. 6B, when the exposure value Ev is Ev10, from the position B in the figure, the exposure time Tv_2 is determined as Tv6.47 and the aperture value Av_2 is determined as AV3.53.

  As described above, when the exposure condition for obtaining the appropriate exposure for non-flash photography and flash photography is determined, the system control unit 50 controls the exposure control unit 40 to set the digital camera 100 as the exposure condition for non-flash photography. (S209).

  After setting the exposure conditions for non-flash photography, if the shutter switch SW2 is not turned on (No in S210) and the shutter switch SW1 is also turned off (No in S211), the process returns to step S205.

  If the shutter switch SW2 (64) is turned on (Yes in S210), the system control unit 50 determines each exposure condition for one non-flash shooting and one flash shooting in continuous shooting (S212). This flow will be described below with reference to FIG.

First, the system control unit 50 reads a predetermined number of consecutive shootings n recorded in the memory 32 (S301). The continuous shooting number n may be a fixed value or may be selectable by the user through the operation unit 70 in FIG. In this embodiment, n = 10. Subsequently, the number of times of shooting for each of the non-flash shooting and the flash shooting is determined (S302). In this special continuous shooting mode, the non-flash shooting and the flash shooting are alternately performed the same number of times, so that the number of shootings is 2 / n each. In this embodiment, since n = 10, each of the non-flash shooting and the flash shooting is 5 times. Next, the system control unit 50 calculates exposure times T1 [s] and T2 in units of time (seconds) from the exposure time Tv_1 for non-light-emission photography and the exposure time Tv_2 for light-emission photography according to the following formulas (Formula 2) and (Formula 3). [S] is calculated.
T1 = (1/2) ^Tv_1 [s] (Formula 2)
T2 = (1/2) ^Tv_2 [s] (Formula 3)
Here, the exposure time Tv_1 for non-light-emission photography and the exposure time Tv_2 for light-emission photography are values expressed in APEX.

By dividing the exposure times T1 [s] and T2 [s] of each photographing calculated from the above formulas (Equation 2) and (Equation 3) by the number of times of photographing n / 2 for each photographing, The exposure time T1 ′ [s] for flash photography and the exposure time T2 ′ [s] for one flash photography are reset (S303 / S304). Expressions (Expression 4) and (Expression 5) for determining the exposure time T1 ′ [s] for one non-flash photography and the exposure time T2 ′ [s] for one flash photography are shown below.
T1 ′ = T1 / (n / 2) [s] (Formula 4)
T2 ′ = T2 / (n / 2) [s] (Formula 5)
In this embodiment, the exposure time T1 ′ [s] for one non-flash photography is T1 ′ = T1 / 5 [s], and the exposure time T2 ′ [s] for one flash photography is T2 ′ =. T2 / 5 [s]. In the present embodiment, the values determined in step S207 and step S208 are used for the aperture and shooting sensitivity of one non-flash shooting and one flash shooting, respectively.

  Next, the strobe 45 pre-emits with a pre-emission amount set in advance (S213). The system control unit 50 performs a photometric process, and measures the subject brightness in the pre-flash to obtain a photometric value ΔEv. This photometric value ΔEv is expressed by a difference from the appropriate level, and this value is substituted into the following equation (Equation 6) to calculate a guide number for obtaining an appropriate exposure.

Here, GNo. Is a guide number, ΔEv is a photometric value, and a and b are predetermined values.
Next, the strobe light emission time is calculated using the guide number calculated by the mathematical formula (Formula 6). The system control unit 50 stores a guide number and a light emission time table for the number of times of light emission photographing as shown in FIG. In the digital camera 100 of the present embodiment, for example, when the guide number calculated from the mathematical formula (Formula 6) is 7.46 and the number n / 2 of flash photography is 5, 1 from the table shown in FIG. The strobe light emission time Ts in each flash photography is determined to be 60 μs.

Here, the flash emission time Ts [s] for one flash shooting at each shooting count shown in FIG. 7 is such that the total flash emission amount when the flash emission is performed n / 2 times is always constant. Has been determined. The strobe light emission time Ts [s] for one flash photography in this embodiment will be described below. In this embodiment, the strobe 45 is an LED strobe. FIG. 8 is a conceptual diagram of a strobe light emission control signal for controlling the light emission of the strobe 45 by the system control unit 50 and the light emission characteristics of the LED strobe by the strobe light emission control signal. The LED strobe emits light like a light emission characteristic 801 by a light emission control signal 802. Here, the light emission time Tso [s] is the light emission time when the number of times of flash photography is one. Further, the time integration of the light emission characteristics indicates the light emission amount. Since the LED strobe has a steep rise and fall of the light emission intensity with respect to the light emission control signal, the light emission amount with respect to the light emission time may be linear. Therefore, the flash emission time Ts [s] for one flash photography in this embodiment is determined by the following equation (Equation 7).
Ts = Tso / (n / 2) [s] (Formula 7)
A light emission control signal determined so as to satisfy the light emission time Ts [s] when the light emission time Ts [s] is determined by the mathematical expression (Expression 7) is shown in 804, and the light emission characteristics of the LED strobe by the light emission control signal 804 are shown in 803. Shown in Here, the number of flash photography n / 2 = 5. Reference numeral 805 shows the light emission characteristics 803 arranged for the number of times of photographing. Comparing the area of 805 representing the total light emission amount of the light emission characteristic 803 with the number of times of photographing five times and the area of 801 representing the light emission amount of the light emission characteristic 801 by the light emission control signal 802, they are almost equal. That is, the total light emission amount when the light emission is performed n / 2 times with the strobe light emission time Ts [s] is substantially equal to the light emission amount with the strobe light emission time Tso [s] when the number of times of flash photography is taken. Therefore, in the present embodiment, the strobe light emission time Ts [s] for one flash photography is determined using Equation (Equation 7). That is, the strobe light emission time table shown in FIG. 7 determined using the mathematical formula (formula 7) is adapted to a strobe having a light emission characteristic that is linear in the light emission amount with respect to the light emission time, such as an LED strobe. It has become.

  Here, consider the case where the strobe 45 is a xenon tube strobe using a xenon tube for the light emitting portion. FIG. 9 is a conceptual diagram showing the light emission characteristics of a xenon tube strobe by a strobe light emission control signal. The xenon tube strobe emits light like a light emission characteristic 901 by a light emission control signal 902. As in the case of the LED strobe, the light emission control signal determined so as to satisfy the light emission time Ts [s] when the light emission time Ts is determined by the mathematical formula (Equation 7) is shown at 904, and the xenon tube by the light emission control signal 904 is shown. The light emission characteristics of the strobe are shown at 903. At this time, the number of times of flash photography is n / 2 = 5. Reference numeral 905 shows the emission characteristics 903 arranged for the number of times of photographing. Since the xenon tube strobe has a gentle change in the light emission characteristic with respect to the light emission control signal as compared with the LED strobe, the relationship between the light emission amount and the light emission time is nonlinear. Therefore, a comparison is made between the area 905 that represents the sum of the light emission amounts of the light emission characteristics 903 for the five shooting times and the area 901 that represents the light emission amount of the light emission characteristics 901 by the light emission control signal 902. Therefore, when the strobe 45 is a xenon tube strobe, the flash emission time Ts [s] of one flash shooting when the number of flash shootings is a plurality of times cannot be determined using the formula (Formula 7). .

In a xenon tube strobe, when the flash emission time Ts [s] is determined so that the flash emission time of the flash emission time Tso [s] is equal to the total light emission when the flash photography is performed n / 2 times, A light emission characteristic according to the strobe light emission time Ts [s] is indicated by 906. At this time, the number of times of light emission photographing n / 2 = 5, and the light emission characteristics 906 are arranged for the number of times of photographing. Here, the area of the light emission characteristic 906 representing the total amount of light emission by the strobe light emission time Ts is equal to the area of the light emission characteristic 901 representing the light emission quantity by the strobe light emission time Tso [s]. At this time, the relationship between the flash emission time Tso [s] when the number of shootings is one and the flash emission time Ts [s] of one flash shooting when the number of shootings is a plurality of times is expressed by Equation (Equation 8). It becomes.
Ts ′> Ts / (n / 2) [s] (Formula 8)
The strobe light emission time Ts [s] is longer than the time divided by the number of times of shooting n / 2, as shown by the equation (Equation 8). However, the exposure time T2 ′ [s] for one flash photography is obtained by dividing the exposure time T2 [s] for the flash photography by the number of times n / 2. Therefore, there may be a case where the flash emission time Ts [s] is longer than the exposure time T2 ′ [s] of flash photography. For example, reference numeral 907 denotes an exposure period of flash photography when the light emission characteristic of the flash emission time Ts [s] of single flash photography is 906. An exposure period of one flash photography obtained by dividing the exposure time T2 [s] of the exposure period 907 by the number of photographing times n / 2 is shown at 908. At this time, the flash emission time Ts [s] for one flash photography is shorter than the exposure time T2 ′ [s] for one flash photography. However, when the exposure period of the flash photography is 909, the exposure period of one flash photography obtained by dividing the exposure time T2 [s] of the exposure period 909 by the number of photography n / 2 is 910. At this time, the flash emission time Ts [s] for one flash photography is longer than the exposure time T2 ′ [s] for one flash photography. In this case, the entire light emission amount due to the strobe light emission time Ts [s] is not exposed.

As described above, when the flash emission time Ts [s] of one flash photography satisfies the following formula (Equation 9) between the exposure time T2 ′ [s] and the exposure time T2 ′ [s], even if it is a xenon tube strobe The invention can be applied.
Ts ′ ≦ T2 ′ (Formula 9)
When the strobe 45 is a xenon tube strobe, the system control unit 50 stores a table of the flash time with respect to the guide number and the number of shootings of flash photography in accordance with the light emission characteristics of the xenon tube strobe. The light emission amount Ts [s] is determined. This table has the same contents as those shown in FIG. 7, but the light emission time for each guide number and each number of times of shooting is a time that matches the light emission characteristics of the xenon tube strobe. If the mathematical expression (Formula 9) is not satisfied due to the exposure condition and the number of photographing times, a warning is displayed on the display unit 30 so that continuous photographing is not performed.

  Next, in accordance with the conditions reset in step S212 and the flash emission time determined in step S213, non-flash shooting and flash shooting are alternately and continuously performed (S214). This flow will be described below with reference to FIG.

  First, the system control unit 50 sets the exposure to the exposure condition for non-flash photography that has been reset in step S303 in FIG. 3 (S401), and performs non-flash photography (S402). Subsequently, the system control unit 50 sets the exposure to the exposure condition of the flash photography that has been reset in step S303 in FIG. 3 (S403), and performs flash photography with the flash emission amount determined in step S304 in FIG. S404). It is determined whether or not the total number of shootings of the above-described non-flash shooting and flash shooting has been performed up to a predetermined continuous shooting count n (S405). If the predetermined number n of continuous shooting has not been reached (No in S405), the process returns to step S401 and repeats the processes in steps S401 to S405.

  FIG. 10 is a conceptual diagram showing the relationship among the exposure time, strobe light emission time, and shooting period required for continuous shooting in the shooting flow shown in FIG. In the shooting flow shown in FIG. 4, non-flash shooting 1001, flash shooting 1002, and flash emission 1003 are performed at the timing shown in FIG.

  After the continuous shooting in step S214, the image composition unit 42 synthesizes image data of a plurality of images (5 images each in the present embodiment) obtained by non-light emission photography and light emission photography. Then, one synthesized image obtained by synthesizing a plurality of images obtained by flash photography and one synthesized image obtained by synthesizing a plurality of images obtained by non-emission photography are generated (S215). This flow will be described below with reference to FIG.

  First, the value of the counter k indicating the unit image acquired by the number of times of continuous shooting is set to “1” (S501). Next, it is determined whether the value of the counter k is an odd number or an even number (S502). When the value of the counter k is an odd number (Yes in S502), the unit image acquired by the k (odd) number shooting is recorded in the non-light-emitting shot image composition memory (S503). On the other hand, when the value of the counter k is an even number (No in S502), the unit image acquired by the k (even) -th shooting is recorded in the memory for light emission shooting image composition (S504).

  Next, by determining whether the value of the counter k is equal to the number of consecutive shots n, it is determined whether all unit images acquired by n consecutive shots have been recorded in each memory (S505). If the value of the counter k is less than the number of consecutive shots n (No in S505), the process proceeds to step S506, the value of the counter k is incremented, the process returns to step S502, and the allocation of the unit image to each memory is repeated. When all n unit images are recorded in each memory (Yes in S505), all the unit images recorded in the memory for non-light-emitting photographed image composition are added and synthesized (S507). Subsequently, all unit images recorded in the memory for synthesizing the light-emission photographed image are added and combined (S508).

  FIG. 11 is a conceptual diagram showing how a composite image is generated from unit images obtained by continuous shooting. A plurality of (10 in this embodiment) unit images 1101 are acquired by continuous shooting. The unit image 1101 is divided into a plurality of (5 in this embodiment) unit images 1102 acquired by non-flash photography and a plurality (5 in this embodiment) unit images 1103 obtained by light emission photography. Then, one non-light-emitting photographed image 1104 and one light-emitting photographed image 1105 are generated by combining the images.

  The unit image 1102 is photographed with an exposure time T1 'obtained by dividing an exposure time T1 at which proper exposure is obtained by non-light-emission photographing by the number of times n / 2. Therefore, the non-light-emitting photographed image 1104 generated by adding and synthesizing the unit images 1102 by the number of times obtained by photographing the number of times n / 2 is appropriate exposure. Similarly, the unit image 1103 is photographed with an exposure time T2 'obtained by dividing the exposure time T2 at which proper exposure is obtained by flash photographing by the number of photographing times n / 2. Also, the flash emission time Ts ′ for one flash shooting is set by dividing the flash emission time Tso determined by the flash light control by the number of shooting times n / 2. For this reason, the light emission photographed image 1105 generated by adding and synthesizing the unit images 1103 by the number of times obtained by photographing the number of times n / 2 is appropriate exposure.

FIG. 13A is a diagram illustrating an example of an image composition method. Reference numerals 1301, 1303, and 1304 denote unit images captured by continuous shooting, and these unit images are images of horizontal x pixels and vertical y pixels. The unit image acquired by the first shooting is expressed as A ₁ , and the unit image acquired by the k-th shooting is expressed as A _k . Here, image composition is performed from n unit images.

Reference numeral 1302 denotes a data value of each pixel. For example, the pixel data value of the (1,2) coordinate of the unit image acquired by the k-th shooting is represented by a _k (1,2). In the image composition in this embodiment, addition image composition is performed for each pixel data value of the same coordinates from the photographed unit image to generate a non-light-emitting photograph image B (1305) and a light-emitting photograph image C (1306). At this time, the data values of the coordinates of the non-light-emitting photographed image B (1305) and the light-emitting photographed image C (1306) are respectively expressed as the following formulas (Formula 10) and (Formula 11).

  After the image composition in step S215, the generated one non-light-emitting photograph image with proper exposure and light-emission photograph image with proper exposure are recorded in the memory 32. Then, the system control unit 50 performs a quick review display of the generated non-light-emitting captured image and light-emitting captured image on the display unit 30 (S216). In the quick review display, the generated non-flashed image and the flashed image may be displayed in order, or the generated non-flashed image and the flashed image may be displayed on the same screen. May be.

  After the quick review display, the system control unit 50 executes a recording process for writing the acquired image data as an image file to the recording medium 200 (S217).

  As described above, in this embodiment, non-flash photography and flash photography are alternately and continuously performed with a short exposure time obtained by dividing the exposure time for obtaining a proper exposure into the number of continuous photographing times. Therefore, compared to a shooting method in which non-flash shooting and flash shooting are sequentially performed one by one with an exposure time that provides an appropriate exposure, the exposure time per non-flash shooting and flash shooting is shortened, and non-flash shooting. The time difference from the flash photography is reduced. Accordingly, it is possible to reduce a difference in images due to a change in the subject environment between the non-light-emitting captured image and the light-emitting captured image that are continuously captured. In addition, a plurality of unit images with small image differences due to changes in the subject environment are acquired, and a non-light-emitting photographed image and a light-emitting photographed image with appropriate exposure are generated by image composition. It is possible to reduce the difference between the image and the image due to the change in the subject environment.

  In addition, since the exposure time for each photographing is set to a time shorter than the exposure time for obtaining an appropriate exposure, it is possible to reduce deterioration in image quality due to camera shake and subject blur in a unit image obtained by each photographing.

(Example 2)
In Example 1, in image composition when acquiring one non-light-emitting photographed image and light-emitting photographed image by image composition from a plurality of images obtained by alternately performing non-light-emitting photographing and light-emitting photographing several times, A configuration has been described in which additive synthesis is performed for each identical pixel position between captured images to be combined. On the other hand, in the second embodiment, a configuration will be described in which image alignment is performed after alignment processing of a main subject in an image is performed between captured images to be combined.

  Hereinafter, a digital camera as an imaging apparatus according to Embodiment 2 of the present invention will be described. FIG. 1B is a block diagram showing the configuration of the digital camera according to the present embodiment. In FIG. 1B, the image alignment processing unit 44 performs alignment processing for aligning the position of the main subject in the images between the images to be combined. Since other configurations are the same as those of the digital camera 100 according to the first embodiment, the description thereof is omitted. In addition, since the shooting operation in the special continuous shooting mode of this embodiment is the same as that of the first embodiment except for step S215 in FIG. 2, the description other than step S215 is omitted. Hereinafter, parts different from the first embodiment will be described in detail.

  The image registration process and the image composition process in this embodiment are different from the image composition process (S215) in the first embodiment. Therefore, FIG. 14 shows a flowchart of the image alignment process and the image composition process of the present embodiment, which will be described in detail below.

  First, the value of the counter k indicating the unit image acquired by the number of times of continuous shooting is set to “1” (S1401). Next, it is determined whether the value of the counter k is an odd number or an even number (S1402). The determination method is the same as that in step S502 of the first embodiment. If the value of the counter k is an odd number (Yes in S1402), the unit image acquired by the kth (odd) shooting is recorded in the non-light-emitting shot image composition memory (S1403). Next, it is determined whether or not the unit image recorded in the non-light-emitting photograph image composition memory is the first image (S1404). If the unit image recorded in the non-light-emitting image synthesizing memory is the first image (Yes in S1404), the image alignment process and the image synthesis process are not performed, and the process proceeds to step S1408. If the unit image recorded in the non-light-emitting image synthesizing memory is the second or subsequent image (No in S1404), the process proceeds to step S1405. In step S <b> 1405, the image alignment processing unit 44 calculates a motion vector between images recorded in the non-light-emitting captured image synthesis memory to be synthesized.

  Various methods are known as a motion vector detection method, and any method can be used, but the method illustrated in FIG. 15 is used as an example.

  FIG. 15A is a diagram illustrating a state in which a captured image is divided into small blocks. Reference numeral 1501 denotes a photographed image. Here, an image of 3072 pixels wide and 2048 pixels long is photographed. In order to obtain a motion vector, here, the entire screen is divided into small blocks 1502 each having 256 pixels horizontally and 256 pixels vertically. As a result, as shown in FIG. 15A, the block is divided into 12 horizontal blocks and 8 vertical blocks. Next, for each small block 1502, a two-dimensional correlation value with another image for obtaining the motion vector 1503 is obtained. As the correlation value, the small block 1502 is shifted in units of pixels, the sum of the absolute values of the differences between the corresponding pixels is successively obtained, and the shift amount that minimizes the sum is determined as the motion vector of the small block 1502. 1503. The motion vector 1503 shown in FIG. 15B is displayed as (2, 1), which means that the pixel is shifted by 2 pixels in the X direction (image long side direction) and 1 pixel in the Y direction (image short side). The motion vector 1503 is obtained in all the small blocks 1502 as shown in FIG. Further, the frequency of the motion vector 1503 obtained as described above is examined. FIG. 15C shows a histogram in which the frequencies are plotted in order from the mode value. A motion vector between two images is obtained from the histogram thus obtained. For example, in the case of FIG. 15C, the motion vector (2, 1) is the mode value, and becomes a motion vector between the two images.

  Next, in order to perform image synthesis, the image alignment processing unit 44 performs coordinate transformation using the motion vector values obtained in step S1405 so that the non-light-emitting captured images to be synthesized overlap each other (S1406). .

Next, the image synthesizing unit 42 synthesizes the coordinate-converted images, and records the synthesized image in the non-light-emitting photographic image synthesizing memory (S1407). FIG. 13B is a conceptual diagram illustrating the image composition method of this embodiment. Reference numerals 1311 and 1312 denote unit images taken by the continuous shooting. The image size of the unit image A is x horizontal pixels and y vertical pixels. The unit image A ′ (1312) is coordinate-transformed by the motion vector (s, t), and the image size is horizontal x + s pixels and vertical y + t pixels. FIG. 13B shows an example when s> 0 and t> 0. Reference numeral 1313 denotes a data value of each pixel. By adding and synthesizing the unit images A and A ′, a synthesized image D (1314) is generated. In the image composition in this embodiment, the pixel data value of the composite image D (1314) is obtained by the following mathematical formula (Formula 12).
d (i, j) = a (i, j) + a ′ (i + s, j + t) (1 ≦ i ≦ x, 1 ≦ j ≦ y) (Formula 12)

  Next, by determining whether or not the value of the counter k is equal to the number of consecutive shots n, it is determined whether or not the alignment process and the image composition process have been performed on all unit images acquired by n consecutive shots ( S1408). If the value of the counter k is less than the number of consecutive shots n (No in S1408), the process proceeds to step S1409, the value of the counter k is incremented, and the process returns to step S1402.

  In step S1402, if the value of the counter k is an even number (No in S1402), the unit image acquired by the k (even number) shooting is recorded in the memory for light emission shooting image synthesis (S1410). Next, it is determined whether or not the value of the counter k is “2”, thereby determining whether or not the unit image recorded in the memory for luminescent image synthesis is the first one (S1411). If the unit image recorded in the flash photography image composition memory is the first (Yes in S1411), the image alignment process and the image composition process are not performed, and the process proceeds to step S1408. When the unit image recorded in the memory for synthesizing the light emission photographed image is the second or subsequent image (No in S1411), the process proceeds to step S1412. In step S <b> 1412, the image alignment processing unit 44 calculates a motion vector between images recorded in the light-emission photograph image synthesis memory to be synthesized. The calculation method is the same as that in step S1405.

  Next, in order to perform image synthesis, the image alignment processing unit 44 performs coordinate conversion using the motion vector values obtained in step S1412 so that the light-emitting captured images to be combined overlap each other (S1413). The coordinate conversion method is the same as that in step S1406. Next, the image synthesizing unit 42 synthesizes the coordinate-converted images, and records the synthesized image in the flash light emission photographic image synthesis memory (S1414). The image composition method is the same as that in step S1407.

  When the allocation process of unit images to each memory, the alignment process and the image synthesis process in each memory are repeated, and all n unit images are synthesized, (n / 2) unit images are stored in each memory. To be recorded. In each memory, one non-light-emitting photographed image and one light-emitting photographed image are generated from (n / 2) unit images.

  When alignment processing and image composition processing are performed on all n unit images (Yes in S1408), each non-light-emitting photographed image and light-emitting photographed image recorded in each memory are resized by a predetermined calculation. (S1415). In this calculation, for example, in each composite image, clipping is performed so that the image size is maximized from an area where (n / 2) pieces of pixel data are added. Here, the image sizes of the non-light-emitting photographed image and the light-emitting photographed image are made the same.

  FIG. 12A is a conceptual diagram showing how a composite image is generated from a unit image. By continuous shooting, n (10 in this embodiment) unit images 1201 are acquired. Next, the unit image 1201 includes n / 2 (five in the present embodiment) unit images 1202 acquired by non-flash photography and n / 2 (five in this embodiment) unit images 1202 obtained by flash photography. It is divided into unit images 1203. Each n / 2 (five in the present embodiment) non-light-emitting shooting unit image 1202 and light-emitting shooting unit image 1203 are respectively subjected to motion vector detection and coordinate conversion. Next, each of n / 2 (5 in this embodiment) non-light-emitting shooting unit images 1204 whose coordinates have been converted and the light-emitting shooting unit images 1205 whose coordinates have been converted are combined. Each of the non-light-emitting photographed composite image 1206 and the light-emitting photographed composite image 1207 generated by the image composition is resized, and each of the non-light-emitting photographed image 1208 and the light-emitting photographed image 1209 is generated.

As described above, in the second embodiment, the configuration in which the image is synthesized after performing the alignment process between the captured image data to be synthesized is described.
In the configuration described in the first embodiment, addition and combination are performed for each same pixel position between the captured images to be combined, so that camera shake and subject shake between unit images cannot be reduced. On the other hand, the configuration described in the second embodiment is a configuration in which image alignment is performed after performing alignment processing between captured image data to be combined. As a result, a so-called electronic camera shake correction effect can be obtained, and the effects of camera shake and subject camera shake between unit images can be reduced. Therefore, it is possible to reduce deterioration in image quality due to camera shake and subject shake of each non-light-emitting photographed image and light-emitting photographed image generated by image composition from the acquired unit images.

Example 3
In Example 1 and Example 2, non-flash shooting and flash shooting are alternately and continuously performed for a predetermined number of consecutive shooting times (n times), and the obtained n unit images are combined, and each of the appropriate images is combined. A configuration has been described in which an exposure non-light-emitting photograph image and a proper exposure light-emitting photograph image are acquired. In contrast, in the configuration described in the third embodiment, the number of times of photographing m is larger than the number of times of photographing n necessary to acquire each of the non-light-emitting photographed image with appropriate exposure and the light-emitting photographed image with appropriate exposure. Shoot (m> n). Then, arbitrary n unit images are selected from the acquired m unit images. The selected n unit images are respectively combined to obtain a non-light-emitting photograph image with proper exposure and a light-emission photograph image with proper exposure. That is, a part of the plurality of images obtained by one photographing operation is synthesized to obtain one non-light-emitting photograph image with proper exposure and a light-emission photographing image with proper exposure.

Since the configuration of the digital camera according to the present embodiment is the same as that of the digital camera according to the second embodiment, description thereof is omitted. FIG. 16 shows a flowchart of the photographing operation in the special continuous photographing mode of the present embodiment. Processing steps that perform the same operations as those in the first and second embodiments are given the same reference numerals and description thereof is omitted. Hereinafter, parts different from the first and second embodiments will be described in detail.
After step S213, in accordance with the conditions reset in step S212, non-flash photography and flash photography are alternately and continuously performed (S1601). In this embodiment, unlike the first and second embodiments, the actual number of times of photographing is represented by m, and the number of photographing necessary for generating a properly exposed photographed image by image composition is represented by n. ing. Therefore, the exposure time for one non-flash shooting and the flash shooting in continuous shooting and the strobe flash time in one flash shooting are not the actual shooting count m, but the shooting count necessary for image composition, n. Set based on. Note that m, which is the actual number of times of photographing, is a value larger than n, which is the number of times of photographing necessary for image composition. For this reason, the exposure time for each non-light-emitting photographing and light-emitting photographing set in step S212 is a time obtained by dividing the appropriate exposure time by n / 2, and therefore m / 2, which is the actual number of times of photographing. The time is longer than the time obtained by dividing the appropriate exposure time. Furthermore, since the exposure time for each shooting is set based on n / 2, which is the number of shootings required for image composition, the total exposure time for m / 2 shooting is greater than the appropriate exposure time. become longer. The same applies to the flash emission time per flash shooting determined in step S213.

  FIG. 17 shows a flowchart of continuous shooting in step S1601. In addition, the same code | symbol is provided to the process step which performs the same operation | movement as Example 1 and Example 2, and description is abbreviate | omitted. After the non-flash shooting and the flash shooting from step S401 to step S404, it is determined whether or not the number of shooting has reached the predetermined number of times m (S1701). If the predetermined number m of continuous shooting has not been reached (No in S1701), the process returns to step S401 and repeats the processes in steps S401 to S1701. Here, the number of times of photographing m is set to be larger than the number of times of photographing n read in step S301 in FIG. The number m of times of photographing may be determined by setting of the photographing conditions and the photographing mode of the digital camera 100, or may be arbitrarily determined by the user through the operation unit 70 in FIG. In this embodiment, the number m of photographing is assumed to be m = 20.

  After the continuous shooting in step S1601, arbitrary n shot images are selected for image composition from m unit images (m = 20 in this embodiment) acquired by non-flash shooting and flash shooting (S1602). Here, the n images to be selected may be determined by settings such as the shooting conditions and shooting mode of the digital camera 100, or may be arbitrarily determined by the user via the operation unit 70 in FIG.

  Next, the image synthesizing unit 42 synthesizes the selected n unit images, and generates one non-light-emitting photograph image and one light-emitting photograph image (S215).

  FIG. 12B is a conceptual diagram showing a state in which n unit images are selected from m unit images and a composite image is generated. M (20 in this embodiment) unit images 1211 are acquired by continuous shooting, and n (10 in this embodiment) unit images are arbitrarily selected from the unit images 1211. Here, the unit images acquired by the first to fourth shooting are not selected, but the unit images acquired by the fifth to n shootings are selected.

  Of the set n unit images, each of the unit images 1212 acquired by n / 2 non-light-emission shootings and the unit image 1213 acquired by light-emission shootings are subjected to motion vector detection and coordinate conversion is performed. After the coordinate conversion process, the n / 2 non-light-emitting shooting unit images 1214 and the light-emitting shooting unit images 1215 that have undergone coordinate conversion are combined. Each of the non-light-emitting photographed composite images 1216 and the light-emitting photographed composite image 1217 generated by image composition is resized to generate one non-light-emitting photographed image 1218 and light-emitting photographed image 1219, respectively.

  As described above, in Example 3, continuous shooting is performed for a number of times m (m> n) that is greater than the number of times n required for obtaining a non-light-emitting image and a light-emitting image with appropriate exposure. Then, arbitrary n unit images are selected from the acquired m unit images, and each of the unit images is combined to generate one non-light-emitting photograph image and one light-emitting photograph image. As a result, when there is a significant camera shake effect between the acquired unit images, or when a subject unintended by the user is captured during the shooting period, the problem unit image is not selected and there is no problem. It is possible to compose an image using only the image. By doing so, the effect of electronic camera shake correction can be sufficiently obtained by the alignment processing between the unit images, and the image quality of both the non-light-emitting photographed image and the light-emitting photographed image generated by the image composition Can be improved.

  In addition, as shown in FIG. 12B, after continuous shooting is started, the unit image acquired by the arbitrary number of shootings from the beginning is not selected, but the unit image acquired by the subsequent n shootings is selected, whereby the shooting is performed. It is possible to reduce the influence of camera shake during operation.

  Instead of selecting an image as shown in FIG. 12B, the image may be selected with reference to the motion vector of each image in step S215. For example, alignment processing is performed on all of the m captured images that have been captured, and the absolute value of the motion vector of each image is recorded. N unit images having a small absolute value are selected from the absolute values of the recorded motion vectors. According to this method, when camera shake occurs during the shooting period, it is possible to select a unit image that is less affected by camera shake, and by combining the images, deterioration of the image quality of the generated composite image is prevented. be able to.

  In the above-described three embodiments, the configuration in which the non-flash shooting and the flash shooting are alternately and continuously performed when the mode changeover switch 60 is set to the special continuous shooting mode has been described. It may not be the structure which switches the presence or absence of. For example, in a scene where it is unclear whether a good captured image can be obtained with non-flash photography or flash photography, it is determined whether the subject can change due to time change, and if it is determined that the subject can change It may be configured to automatically switch to the above-described continuous shooting.

  In addition, a configuration has been described in which flash photography and non-flash photography are performed the same number of times in one shooting operation, and flash photography and non-flash photography are alternately performed. However, all flash photography is completed in one shooting operation. Any structure that performs at least one non-light-emitting photographing before the image capturing is performed. For example, non-flash photography and flash photography, such as when the flash's charging voltage drops during continuous shooting and the flash can no longer fire, continuously taking non-flash photography, then charging the flash and taking flash photography again. There may be a part that does not perform alternately.

  In addition, the configuration in which non-flash shooting is performed first in continuous shooting has been described, but the configuration in which flash shooting is performed first may also be used.

  Further, the number of non-flash photography and the number of flash photography may not be the same. For example, in order to reduce the difference in exposure time between non-flash photography and flash photography, the number of non-flash photography is made larger than the number of flash photography, and the combined number of non-flash photography images is It may be greater than the number of composites.

  The strobe as the light emitting means may be a built-in strobe built into the camera body or an external strobe detachable from the camera body.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. A part of the above-described embodiments may be appropriately combined.

(Other examples)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program. It is a process to be executed.

DESCRIPTION OF SYMBOLS 14 Image pick-up part 22 Image processing part 30 Display part 40 Exposure control part 42 Image synthetic | combination part 44 Image alignment processing part 45 Strobe 50 System control part 60 Mode switch 62 Shutter switch SW1
64 Shutter switch SW2
70 Operation unit 100 Digital camera

Claims (7)

An imaging device capable of performing light emission photography and non-light emission photography in which a light emitting unit emits light in one photographing operation, respectively, a plurality of times,
Imaging means for imaging a subject;
Metering means for metering the subject;
Determining means for determining an exposure time of the imaging means per one time of the light emission photography and the non-light emission photography based on a photometric result by the photometry means;
Image synthesizing means for synthesizing a plurality of images obtained by the imaging means with the exposure time determined by the determining means, and generating a synthesized image;
Control means for controlling to perform at least one non-flash photography before all the flash photography is completed in one photographing operation;
Each light emission amount of the plurality of flash photographing operations performed in one photographing operation is equal, and the total light emission amount of the plurality of light emission photographings is a target light emission amount determined based on a light measurement result by the photometry means. And a light emission control means for causing the light emission means to emit light by extending a total light emission time of the plurality of light emission photographings more than a light emission time required for obtaining the target light emission amount in one light emission. ,
The image synthesizing unit generates a synthesized image obtained by synthesizing a plurality of images obtained by the flash photography and a synthesized image obtained by synthesizing the plurality of images obtained by the non-emission photography in one photographing operation. An imaging apparatus characterized by that.   The control means performs control so that the light emission photography and the non-light emission photography are alternately performed with the same number of times of the light emission photography and the non-light emission photography performed in one photographing operation. Item 2. The imaging device according to Item 1.   The determining means calculates an appropriate exposure time for each of the light emission photography and the non-light emission photography based on a photometric result obtained by the photometry means, and the light emission based on the calculated appropriate exposure time and the number of times of each photography. The imaging apparatus according to claim 1, wherein the exposure time per one time of photographing and non-light-emitting photographing is determined. The determining means determines the exposure time per time of the light emission photography and the non-light emission photography as a time longer than a time obtained by dividing the calculated appropriate exposure time by the number of times of each photography,
The image synthesizing means includes a synthesized image obtained by synthesizing a part of a plurality of images obtained by the light emission photographing by one photographing operation, and a plurality of images obtained by the non-light emitting photographing. The imaging apparatus according to claim 3, wherein a combined image obtained by combining a part of the images is generated.   The image synthesizing means combines a composite image obtained by synthesizing a number of images from which a proper exposure is obtained among a plurality of images obtained by the light emission photographing by one photographing operation, and a plurality of images obtained by the non-light emission photographing. The imaging apparatus according to claim 4, wherein a combined image is generated by combining a number of images from which a proper exposure is obtained.   6. The imaging apparatus according to claim 1, wherein the image synthesizing unit generates a synthesized image by aligning a main subject in the image. An imaging apparatus having an imaging unit for imaging a subject and a photometric unit for photometry of the subject, and capable of performing a plurality of times of light emission photography and non-light emission photography in which the light emission means emits light by one photographing operation Control method,
A determination step of determining an exposure time of the imaging means per one time of the light emission photography and the non-light emission photography based on a photometric result by the photometry means;
An image compositing step for compositing a plurality of images obtained by the imaging means with the exposure time determined in the determining step to generate a composite image with appropriate exposure;
A control step for controlling to perform at least one non-flash photography before all the flash photography is completed in one photographing operation;
Each light emission amount of the plurality of flash photographing operations performed in one photographing operation is equal, and the total light emission amount of the plurality of light emission photographings is a target light emission amount determined based on a light measurement result by the photometry means. And a light emission control step of causing the light emitting means to emit light by extending a total light emission time of the plurality of light emission photographings more than a light emission time necessary for obtaining the target light emission amount in one light emission. ,
The image composition step generates a composite image obtained by combining a plurality of images obtained by the light emission photography and a composite image obtained by combining the plurality of images obtained by the non-light emission photography in one photographing operation. And a method of controlling the imaging apparatus.

Images