JP2009218725A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus with a continuous shooting function capable of obtaining two or more pieces of photographed image data of different characteristics such as recording sensitivity and an S/N. <P>SOLUTION: A digital camera is provided with a solid-state imaging element 5 and an imaging element drive part 10 for driving the solid-state imaging element 5, and a continuous shooting mode of continuously performing imaging for two or more times by the solid-state imaging element 5 and recording two or more pieces of the photographed image data obtained by the two or more times of imaging can be set. During the continuous shooting mode, the imaging element drive part 10 changes a method of driving the solid-state imaging element 5 in each of the two or more times of imaging. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an imaging apparatus including a solid-state imaging device and a driving unit that drives the solid-state imaging device.

  As a photographing mode of a digital camera, still image photographing by charge mixing (pixel thinning) is known (see Patent Document 1). In this still image shooting, by reducing the number of pixels to be read, not only the reading time per shot image data is shortened, but also the signal amount is increased by charge mixing and multiplied by the imaging signal output from the solid-state imaging device. Since the recording sensitivity (ISO sensitivity) can be improved without increasing the gain, the S / N can be improved with respect to the normal photographing. On the other hand, by performing charge mixing, the number of pixels to be read is reduced, so that the resolution of the captured image data is reduced with respect to normal imaging. Here, since the priority of S / N and resolution in the photographic image data varies depending on the subject and the user's preference, there may be cases where photographic image data with good S / N is preferable even if the resolution is reduced.

  However, it is difficult for the user to understand the mechanism of charge mixing and to determine the condition of charge mixing according to the subject, S / N, and resolution preference before exposure and recording sensitivity in conjunction with the recording sensitivity conditions. This is a burden on the user. Further, in the conventional photographed image data, since there is no means for the user to determine the presence or absence of charge mixing after photographing, there is a problem in terms of convenience such as comparison and selection of photographed image data.

JP 2001-285585 A

  The present invention has been made in view of the above circumstances, and provides an imaging apparatus having a continuous shooting function capable of obtaining a plurality of captured image data having different characteristics such as recording sensitivity and S / N in the same scene. The purpose is to do.

  The imaging device of the present invention is an imaging device having a solid-state imaging device and a driving unit that drives the solid-state imaging device, and performs imaging a plurality of times continuously by the solid-state imaging device. The continuous shooting mode for recording a plurality of captured image data obtained by the above can be set, and in the continuous shooting mode, the driving means drives the solid-state imaging device in each of the multiple times of imaging. change.

  In the imaging apparatus of the present invention, the driving method of the solid-state imaging device for at least one of the plurality of times of imaging includes mixing charges accumulated in photoelectric conversion elements included in the solid-state imaging device, and mixing Charge mixing drive for outputting a signal corresponding to the generated charge.

  In the imaging apparatus according to the aspect of the invention, the driving unit performs imaging by the charge mixing drive at least twice in the continuous shooting mode, and changes the number of charges mixed in each of the charge mixing driving at least twice. .

  The imaging apparatus according to the present invention includes a signal amplifying unit that amplifies a signal output from the solid-state imaging device, and an amplification factor by the signal amplifying unit of a signal output from the solid-state imaging device by normal driving without mixing charges. Is α, the amplification factor β by the signal amplification means of the signal output from the solid-state imaging device by the charge mixing drive is set to n, and β = α / n where n is the number of charges mixed in the charge mixing drive. And an amplification factor control means for controlling.

  In the imaging apparatus of the present invention, when the exposure determined at the time when the shooting instruction is performed in the continuous shooting mode is α, the exposure β at the time of the charge mixture driving is the exposure β in the charge mixture driving. Exposure control means for controlling the number of charges to be n and β = α / n.

  In the imaging apparatus according to the aspect of the invention, the driving unit performs the plurality of times of imaging by the charge mixing driving and normal driving without mixing charges, and the charge mixing driving is performed before the normal driving. carry out.

  In the imaging apparatus according to the aspect of the invention, the driving unit performs the plurality of times of imaging by the charge mixing driving and the normal driving two or more times. It carries out in order with many mixing numbers.

  In the image pickup apparatus of the present invention, the driving means performs the plurality of times of image pickup only by the charge mixture drive, and the charge mixture drive is executed in the order of the charge mixture number.

  An imaging apparatus according to the present invention includes a recording unit that records on a recording medium an image file composed of captured image data obtained by the charge mixing drive and attached information related to the captured image data, and the recording unit includes the captured image Information on the number of charges mixed in the charge mixture driving is recorded in the attached information of the data.

  The imaging apparatus of the present invention includes a recording unit that records, on a recording medium, an image file composed of a plurality of photographed image data obtained by the plurality of times of imaging and attached information regarding each of the plurality of photographed image data, The recording unit records information on the number of charges mixed in the charge mixing drive in the attached information of the captured image data obtained by the charge mixing drive among the plurality of photographed image data.

  When the image pickup apparatus of the present invention displays an image based on the photographed image data on a display unit, the display control unit displays a parameter related to noise and a parameter related to the resolution together with the image. When the parameters related to noise and the parameters related to resolution of the captured image data generated based on the signal output from the solid-state image sensor by normal driving without charge mixing are X and Y, respectively. A parameter related to noise and a parameter related to resolution of the captured image data generated based on a signal output from the solid-state imaging device by the charge mixing drive indicate the number of charges mixed in the charge mixture drive. n is x = n * X and y = Y / n, respectively.

  The imaging apparatus of the present invention includes signal processing means for performing signal processing on a signal output from the solid-state imaging device, and the signal processing means performs driving performed to obtain the signal with respect to the signal. Perform signal processing according to the method.

  In the image pickup apparatus of the present invention, for the signal output from the solid-state image sensor by the charge mixing drive, the signal processing unit performs recording in which the number of pixels of photographed image data generated from the signal is set in advance. Processing for reducing or enlarging the captured image data generated from the signal is performed so that the number of pixels is reached.

  The image pickup apparatus of the present invention can select and record arbitrary image data from a plurality of photographed image data obtained by the plurality of times of image pickup.

  In the imaging apparatus of the present invention, the solid-state imaging device is a CCD solid-state imaging device.

  In the imaging apparatus of the present invention, the solid-state imaging device is a MOS solid-state imaging device.

  According to the present invention, it is possible to provide an imaging apparatus having a continuous shooting function capable of obtaining a plurality of captured image data having different characteristics such as recording sensitivity and S / N in the same scene.

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

FIG. 1 is a diagram showing a schematic configuration of a digital camera which is an embodiment of an imaging apparatus of the present invention.
The imaging system of the digital camera shown in the figure includes a photographic lens 1, a CCD type solid-state imaging device 5, a diaphragm 2 provided therebetween, an infrared cut filter 3, and an optical low-pass filter 4.

  The solid-state imaging device 5 includes a large number of photoelectric conversion elements formed in a semiconductor substrate, a plurality of vertical charge transfer paths for transferring charges generated in each of the large number of photoelectric conversion elements in a vertical direction, and a plurality of vertical conversion paths. A horizontal charge transfer path for transferring the charge transferred through the charge transfer path in a horizontal direction orthogonal to the vertical direction, and an output amplifier for converting the charge transferred through the horizontal charge transfer path into a signal corresponding to the charge amount With.

  A system control unit 11 that performs overall control of the electrical control system of the digital camera controls the flash light emitting unit 12 and the light receiving unit 13 and controls the lens driving unit 8 to adjust the position of the photographing lens 1 to the focus position and zoom. The exposure amount is adjusted by adjusting the aperture amount of the aperture 2 via the aperture drive unit 9.

  Further, the system control unit 11 drives the solid-state imaging device 5 via the imaging device driving unit 10 and outputs a subject image captured through the photographing lens 1 as an imaging signal. An instruction signal from the user is input to the system control unit 11 through the operation unit 14. The operation unit 14 includes a release button for giving a shooting instruction, a continuous shooting setting button for setting a continuous shooting mode, and the like.

  The electric control system of the digital camera further includes an analog signal processing unit 6 that performs analog signal processing such as correlated double sampling processing connected to the output of the solid-state imaging device 5, and RGB output from the analog signal processing unit 6. And an A / D converter 7 for converting the color signals into digital signals, which are controlled by the system controller 11. The analog signal processing performed by the analog signal processing unit 6 includes signal amplification processing for multiplying the imaging signal output from the solid-state imaging device 5 by a predetermined gain and amplifying it.

  Further, the electric control system of the digital camera includes a main memory 16, a memory control unit 15 connected to the main memory 16, a digital signal processing unit 17 that generates photographed image data from an imaging signal, and a digital signal processing unit 17. Mounted on the back of the camera, etc., a compression / decompression processing unit 18 that compresses the image data generated in step 1 into a JPEG format or decompresses the compressed image data, an external memory control unit 20 to which a detachable recording medium 21 is connected. The display control unit 22 is connected to the liquid crystal display unit 23, which are connected to each other by a control bus 24 and a data bus 25, and controlled by a command from the system control unit 11.

  The image sensor driving unit 10 can drive the solid-state image sensor 5 by a plurality of driving methods. The plurality of driving methods include normal driving in which charges accumulated in each of a large number of photoelectric conversion elements included in the solid-state imaging element 5 are transferred without being mixed on the charge transfer path and output as imaging signals, and the solid-state imaging element 5 Charge mixing driving in which charges of the same color component accumulated in each of a large number of photoelectric conversion elements included are mixed and transferred on a charge transfer path and output as an imaging signal.

  A well-known method can be adopted for the charge mixing drive. The charge mixing method includes, for example, a method of mixing two charges of the same color component adjacent in the vertical direction on the vertical charge transfer path, or a method of mixing two charges of the same color component adjacent in the horizontal direction on the horizontal charge transfer path. And a method of further mixing on the horizontal charge transfer path a charge obtained by mixing on the vertical charge transfer path and a charge obtained by mixing on the horizontal charge transfer path.

  In the present embodiment, the image pickup device driving unit 10 mixes and transfers four charges of the same color component and mixes the first charge mixture drive for mixing and transferring two charges of the same color component as charge mixing driving. Two types of charge mixing drive can be implemented, but three or more types may be implemented. The total number of charges of the same color component mixed together in the charge mixing drive is defined as the charge mixing number. That is, when the number of charge mixtures is n, the first charge mixture drive can be referred to as n = 2 charge mixture drive, and the second charge mixture drive can be referred to as n = 4 charge mixture drive.

  When the continuous shooting mode is set, the image sensor driving unit 10 drives the solid-state image sensor 5 in accordance with a shooting instruction, and performs control for continuously performing imaging by the solid-state image sensor 5 M (M is a natural number of 2 or more) times. Do. The imaging element driving unit 10 changes the driving method of the solid-state imaging element 5 in each of M times of imaging. Hereinafter, examples of changing the driving method when M = 2, examples of changing the driving method when M = 3, and examples of changing the driving method when M = 4 are listed.

(When M = 2)
In the first imaging, the solid-state image sensor 5 is driven by charge mixing driving (for example, n = 2 charge mixing driving or n = 4 charge mixing driving), and in the second imaging, the solid-state imaging element 5 is driven by normal driving. To do.
In the first imaging, the solid-state imaging device 5 is driven by charge mixing driving (for example, n = 4 charge mixing driving), and in the second imaging, the charge mixing driving is performed by changing the number of charge mixing from the first (for example, n = 2), the solid-state imaging device 5 is driven.

(When M = 3)
In the first imaging, the solid-state imaging device 5 is driven by n = 4 charge mixing drive, in the second imaging, the solid-state imaging device 5 is driven by n = 2 charge mixing driving, and in the third imaging by normal driving. The solid-state image sensor 5 is driven.
In the first imaging, the solid-state imaging device 5 is driven by n = 9 charge mixture driving, in the second imaging, the solid-state imaging device 5 is driven by n = 4 charge mixing driving, and in the third imaging, n = 2. The solid-state imaging device 5 is driven by the charge mixing drive.

(When M = 4)
In the first imaging, the solid-state imaging device 5 is driven by the charge mixing drive of n = 9, in the second imaging, the solid-state imaging device 5 is driven by the charge mixing driving of n = 4, and in the third imaging, n = The solid-state imaging device 5 is driven by the charge mixing driving of 2, and the solid-state imaging device 5 is driven by the normal driving in the fourth imaging.
In the first imaging, the solid-state imaging device 5 is driven by n = 16 charge mixing drive, in the second imaging, the solid-state imaging device 5 is driven by n = 9 charge mixing driving, and in the third imaging, n = The solid-state imaging device 5 is driven by the charge mixing driving of 4, and the solid-state imaging device 5 is driven by the charge mixing driving of n = 2 in the fourth imaging.

  The digital signal processing unit 17 is configured by, for example, a digital signal processor (DSP), and executes a predetermined program, whereby each unit of the signal processing unit 17a, the reproduction control unit 17b, the gain control unit 17c, and the recording control unit 17d. Function.

  The signal processing unit 17a performs imaging processing on the imaging signal that is captured by the solid-state imaging device 5 and output from the solid-state imaging device 5 by this imaging and digitally converted by the A / D conversion unit 7. (Processing for giving red (R), green (G), and blue (B) information to each pixel position of the captured image data), γ correction processing, white balance processing, YC conversion processing (RGB generated at each pixel position) Signal processing such as processing for generating a luminance signal Y and a color difference signal C from the information) is performed to generate captured image data. The captured image data generated here is compressed by the compression / decompression processor 18 and then recorded on the recording medium 21.

  The reproduction control unit 17b performs control to reproduce this image in accordance with an image reproduction instruction based on the captured image data recorded on the recording medium 21. Specifically, the captured image data is read from the recording medium 21, and an image based on the captured image data and information related thereto are displayed on the display unit 23 via the display control unit 22.

  The gain control unit 17 c changes the gain used in the signal amplification processing by the analog signal processing unit 6 in accordance with the method for driving the solid-state imaging device 5 by the imaging device driving unit 10.

  When the continuous shooting mode is set, the recording control unit 17d converts the captured image data generated by the signal processing unit 17a and compressed by the compression / decompression processing unit 18 together with information related to the captured image data, to the external memory control unit 20. To the recording medium 21.

  Hereinafter, the operation in the continuous shooting mode of the digital camera configured as described above will be described. Hereinafter, an example will be described in which three shootings are continuously performed when a shooting instruction is issued when the continuous shooting mode is set.

FIG. 2 is a flowchart for explaining the operation in the continuous shooting mode of the digital camera of the present embodiment.
When the release button is pressed halfway and an AF (autofocus) or AE (automatic exposure) instruction is issued, the system control unit 11 performs AF processing and determines the exposure. Next, when the release button is fully pressed to give a shooting instruction, the system control unit 11 determines whether or not the continuous shooting mode is set (step S1). If the continuous shooting mode is not set, the image sensor driving unit 10 performs normal driving with the determined exposure (step S9).

  On the other hand, when the continuous shooting mode is set, the system control unit 11 determines whether or not the setting for performing the continuous shooting with the recording sensitivity (ISO sensitivity) fixed is set (step S2). Whether or not this recording sensitivity is fixed can be set by the user. If the continuous shooting mode is set in step S1, the imaging element driving unit 10 sets the charge mixture number n to an initial value = “4”.

  If the recording sensitivity is set to be fixed (step S2: YES), the gain used for the signal amplification processing in the analog signal processing unit 6 by the gain control unit 17c is a specified gain set during normal driving. 1 / n (step S3). Since “n” in step S3 uses the value set at the time of step S2, in the example of this embodiment, the gain used for the signal amplification processing in the analog signal processing unit 6 is set during normal driving. Is set to 1/4 of the specified gain.

  On the other hand, when the setting for fixing the recording sensitivity has not been made (step S2: NO), the gain used for the signal amplification processing in the analog signal processing unit 6 is set by the system control unit 11 during normal driving. The fixed exposure is fixed and a new exposure is determined. This new exposure is obtained by multiplying the determined exposure by 1 / n (step S4). The value set at the time of step S2 is also used for “n” here.

  Next, the charge mixture driving of the charge mixture number n (= 4) set at the time of step S2 is performed by the image sensor driving unit 10 with the exposure determined in step S4 or the exposure determined at the time of photographing. (Step S5). The imaging signal output from the solid-state imaging device 5 by imaging by this charge mixing drive is amplified with the gain set in step S3 or step S4, converted into a digital signal, and input to the digital signal processing unit 17.

  The signal processing unit 17a generates the captured image data A from the imaging signal obtained by this driving, and the captured image data A is set so that the number of pixels of the generated captured image data A becomes a preset number of recording pixels. A process of reducing or enlarging is performed (step S6). Specifically, when the preset number of recording pixels is m and the maximum number of pixels that can be recorded by the digital camera of this embodiment is 1, the captured image data A is multiplied by (n * m / l) times. Zoom in or out. Note that the process of step S6 may be omitted.

  The enlarged or reduced photographed image data A is compressed and then recorded on the recording medium 21 by the recording control unit 17d.

  Here, as shown in FIG. 3A, the recording control unit 17d is an image file that includes an image data area for recording captured image data and a header area that is an area for recording additional information related to the captured image data. Is recorded on the recording medium 21, the captured image data A is recorded in the image data area of the image file, and information on the number of charge mixtures in driving for obtaining the captured image data A (information that n = 4), The parameter information related to the resolution of the captured image data A, the parameter information related to the S / N of the captured image data A, and the recording sensitivity information of the captured image data A are recorded in the header area as attached information.

  If the recording sensitivity is not set to be fixed, the recording control unit 17d records the recording sensitivity in association with the captured image data obtained by normal driving (this is a preset value, for example, ISO100). ) Information obtained by multiplying the charge mixture number n (= 4) of charge mixture driving for obtaining the photographed image data A (= ISO400) information on the recording sensitivity of the photographed image data A to be recorded in the header area. And

  Next, the system control unit 11 determines whether or not the number of times of photographing has reached the prescribed number of times of photographing (in this embodiment, twice) (step S7). Here, since the number of times of photographing is one, it is determined that the prescribed number of times of photographing has not been reached, and the value of the charge mixture number n is updated to a value smaller than the current value (n = 4 to n = 2) ( Steps S8) and S2 to S6 are performed to generate captured image data B.

  The photographed image data B is recorded in the image data area of the image file on the recording medium 21, and information on the number of charge mixtures in driving for obtaining the photographed image data B (information of n = 2) and the photographed image data B Information on the parameters related to the resolution, information on the parameters related to S / N of the captured image data B, and information on the recording sensitivity of the captured image data B are recorded in the header area of the image file.

  If the recording sensitivity is not set to be fixed, the recording control unit 17d includes the captured image data B in the information of the recording sensitivity (= ISO100) recorded in association with the captured image data obtained by normal driving. A value (= ISO200) obtained by multiplying the number n (= 2) of charge mixture driving for obtaining the charge mixture is used as information on the recording sensitivity of the photographed image data B to be recorded in the header area.

  When it is determined in step S7 that the number of times of photographing has reached the prescribed number of times of photographing, normal driving is performed by the image sensor driving unit 10 (step S9), and from the imaging signal output from the solid-state image sensor 5 by this normal driving. Captured image data C is generated. In step S9, imaging is performed with the exposure determined at the time when the shooting instruction is given, and the imaging signal obtained by this imaging is amplified with a specified gain set during normal driving.

  The captured image data C is recorded in the image data area of the image file on the recording medium 21, and information on the number of charge mixtures in driving for obtaining the captured image data C (information that n = 0) and the captured image data C Parameter information related to resolution, parameter information related to S / N of the captured image data C, and recording sensitivity information of the captured image data C (recording sensitivity set during continuous shooting, for example, ISO 100). Recorded in the header area of the image file.

  In the above description, the captured image data A, B, and C and their associated information are recorded in separate image files. However, there are a plurality (for example, three) sets of image data areas and header areas. An image file as shown in FIG. 3B is generated on the recording medium 21, and the photographed image data A, B, C and associated information corresponding thereto are recorded in the image file. good.

  As shown in FIG. 3B, in the uppermost image data area and the corresponding header area, the photographed image data A and its associated information are recorded, and the middle image data area and the corresponding header are recorded. The captured image data B and associated information related thereto may be recorded in the area, and the captured image data C and associated information related thereto may be recorded in the lowermost image data area and the corresponding header area.

  In this way, it is possible to manage a plurality of photographed image data obtained by continuous shooting using a single image file, and to improve convenience when confirming the photographed image data later. it can.

  The parameter information related to the resolution of the captured image data is an index indicating the level of resolution, and in this embodiment, the level of resolution is expressed by the number of stars. The parameter information related to the S / N of the photographed image data is an index indicating the quality of the S / N. In this embodiment, the information indicating the quality of the S / N by the number of asterisks is used. These pieces of information are generated by the recording control unit 17d.

  The recording control unit 17d sets a parameter related to noise and a parameter related to resolution (number of stars) of the captured image data generated based on a signal output from the solid-state imaging device 5 by normal driving to the reference value X. , Y, and a parameter related to noise and a parameter related to resolution (number of stars) of the captured image data generated based on the signal output from the solid-state imaging device 5 by the charge mixing drive. Where n is the number of mixed charges in x, and x = n * X and y = Y / n.

  Next, an operation for reproducing the three captured image data recorded on the recording medium 21 by the operation as described above will be described. FIG. 4 is a view showing a display example of an image based on captured image data obtained by continuous shooting with the digital camera of the present embodiment. FIG. 4 shows a display example at the time of reproducing captured image data recorded with the recording sensitivity fixed.

  When there is an instruction to reproduce the photographed image data C, the reproduction control unit 17b reads the photographed image data C and its attached information from the recording medium 21. Then, an image based on the captured image data C is displayed on the display unit 23. Further, a star based on the parameters included in the attached information of the photographed image data C is synthesized and displayed on the image (FIG. 4A). This star indicates that the greater the number, the higher the resolution and the better the S / N. In normal driving, charge mixing is not performed, so the resolution is the highest (4 stars) in continuous shooting.

  When there is an instruction to reproduce the captured image data B, the reproduction control unit 17b reads the captured image data B and its associated information from the recording medium 21. Then, an image based on the captured image data B is displayed on the display unit 23. Also, stars based on parameters included in the attached information of the photographed image data B are synthesized and displayed on the image (FIG. 4B). In the charge mixture drive of n = 2, the resolution is lower than in the normal drive (star becomes 1/2 of (a)). However, as a result of the charge mixture, the analog signal processing unit 6 sets the resolution. Therefore, the amount of noise to be amplified is reduced, and the S / N is improved (star is twice that of (a)).

  When there is an instruction to reproduce the photographed image data A, the reproduction control unit 17b reads the photographed image data A and its attached information from the recording medium 21. Then, an image based on the captured image data A is displayed on the display unit 23. Further, stars based on the parameters included in the attached information of the photographed image data A are combined and displayed on the image (FIG. 4C). In the charge mixture drive with n = 4, the resolution is lower than that in the charge mixture drive with n = 2 (star becomes 1/2 of (b)), but the number of charge mixture is increased. / N is improved (star is twice that of (b)).

  As described above, according to the digital camera of the present embodiment, when a shooting instruction is given in the continuous shooting mode, the imaging by the charge mixing drive of n = 4, the imaging by the charge mixing driving of n = 2, and n = 0, normal imaging is continuously performed in this order. If the recording sensitivity is set to be fixed, the image pickup signal output from the solid-state image pickup device 5 is not amplified with the same gain in each image pickup, but the drive with a large number of charge mixtures is performed. Amplification is performed with a lower gain as the image pickup signal obtained in step 1 is obtained. For this reason, it is possible to record three photographed image data having different resolutions and S / N by one photographing instruction.

  In the digital camera of this embodiment, since a plurality of captured image data having different S / N can be obtained by one shooting without the user being aware of charge mixing, S / N is used as a criterion for determining whether the image is good or bad. Even an important user can obtain captured image data with satisfactory image quality. Also, even for users who place importance on resolution rather than S / N, it is possible to record a plurality of photographed image data with different resolutions, so that it is possible to obtain photographed image data with satisfactory image quality.

  Further, according to the digital camera of the present embodiment, when the recording sensitivity is set not to be fixed, the gain in the analog signal processing unit 6 is always constant, and the exposure is increased as the charge mixture number n increases. Therefore, it is possible to obtain three photographed image data having different recording sensitivities with the same S / N by one photographing. For this reason, it is possible to obtain a good image even in a scene in which the recording sensitivity is not known.

  Further, according to the digital camera of the present embodiment, in step S6 in FIG. 2, the captured image data is enlarged or reduced so as to have a preset number of recording pixels, so the resolution is the same and the S / N is different. Three pieces of photographed image data can be obtained, and it is possible to determine whether the image quality is good or bad only by comparing S / N.

  In addition, according to the digital camera of the present embodiment, when the captured image data obtained by continuous shooting is reproduced, the image quality of the captured image data is represented by a star that indicates whether the resolution is high or low and the S / N is good or bad. It can be intuitively grasped by numbers. In this way, by informing the user of the advantages and disadvantages of charge mixing, the user can easily select a favorite image, and convenience is improved.

  In the digital camera of the present embodiment, imaging by charge mixture driving is performed before imaging by normal driving. In the charge mixing drive, the number of signals output from the solid-state imaging device 5 is smaller than that in the normal drive, and therefore the drive time can be shorter than that in the normal drive. For this reason, by performing the charge mixing drive before the normal drive, the time until the start of the next exposure can be made shorter than when the normal drive is performed first. As a result, the continuous shooting interval can be shortened, and the subject can be prevented from shifting. In addition, when the charge mixing drive is performed a plurality of times, the subject misalignment can be further suppressed by performing the charge mixing drive in order of increasing n as in the present embodiment.

Hereinafter, modifications of the digital camera of this embodiment will be listed.
(1) Before the captured image data A, B, and C are recorded on the recording medium 21, they are reproduced and displayed on the display unit 23 so that only the captured image data selected by the user from the displayed captured image data can be recorded. May be. As a result, unnecessary data is not recorded, and the recording medium can be used efficiently.
(2) The normal driving in step S9 in FIG. 2 may be omitted.

(3) Although the solid-state imaging device 5 is a CCD type, it may be a MOS type.
FIG. 5 is a diagram showing an example of a structure that enables charge mixing in a MOS type solid-state imaging device.
As shown in FIG. 5, between the two adjacent photoelectric conversion elements 51a and 51b, a charge for temporarily storing the charge generated and accumulated in each of the two photoelectric conversion elements 51a and 51b. An accumulation unit (floating diffusion) 61 and a signal output circuit 65 that converts the charge accumulated in the charge accumulation unit 61 into a signal and outputs the signal are formed.

  Each of the two photoelectric conversion elements 51a and 51b is connected to the charge storage unit 61 via MOS transistors 60a and 60b. The MOS transistor 60a functions as means for controlling the transfer of the charge accumulated in the photoelectric conversion element 51a to the charge accumulation unit 61 by controlling the voltage applied to the gate. The MOS transistor 60b functions as means for controlling the transfer of the charge accumulated in the photoelectric conversion element 51b to the charge accumulation unit 61 by controlling the voltage applied to the gate.

  The signal output circuit 65 is connected to the charge storage unit 61, and is connected to the reset transistor 62, which is a MOS transistor for resetting the charge stored therein, and the charge storage unit 61, and the charge stored therein is signaled. An output transistor 63 that is a MOS transistor that converts the signal into an output, and a selection transistor 64 that is connected to the output transistor 63 and performs control to output a signal converted by the output transistor 63 to a signal output line. It has a known three-transistor configuration.

Hereinafter, a driving method (charge mixing driving and normal driving) of the solid-state imaging device configured as described above will be described.
<During mixed charge driving>
When the exposure period ends, the image sensor driving unit 10 turns on the two MOS transistors 60 a and 60 b and transfers the charges accumulated in the photoelectric conversion elements 51 a and 51 b to the charge accumulation unit 61. Thereby, in the charge storage unit 61, the charges generated in the two photoelectric conversion elements 51a and 51b are mixed. The charge transfer from each of the two photoelectric conversion elements 51a and 51b to the charge storage unit 61 may be performed simultaneously or with a time difference. Next, the imaging element driving unit 10 turns on the selection transistor 64, outputs the signal converted by the output transistor 63 connected to the selected selection transistor 64 to the signal output line, and ends the imaging operation.

<During normal driving>
When the exposure period ends, the image sensor driving unit 10 turns on the MOS transistor 60 a and transfers the charge accumulated in the photoelectric conversion element 51 a to the charge accumulation unit 61. Next, the image sensor driving unit 10 turns on the selection transistor 64, outputs a signal converted by the output transistor 63 connected to the selected selection transistor 64 to the signal output line, and accumulates it in the photoelectric conversion element 51a. The output of the signal corresponding to the charged electric charge is completed, the reset transistor 62 is turned on, and the electric charge accumulated in the charge accumulating unit 61 is discharged.
Next, the imaging element driving unit 10 turns on the MOS transistor 60 b and transfers the charge accumulated in the photoelectric conversion element 51 b to the charge accumulation unit 61. Next, the image sensor driving unit 10 turns on the selection transistor 64, outputs the signal converted by the output transistor 63 connected to the ON selection transistor 64 to the signal output line, and accumulates it in the photoelectric conversion element 51b. The signal output according to the charged electric charge is completed.

  As described above, even in the MOS type solid-state imaging device, it is possible to perform both the charge mixture driving and the normal driving as described above by sharing the charge storage portion among the plurality of photoelectric conversion elements. . Therefore, the present invention can be applied.

The figure which shows schematic structure of the digital camera which is embodiment of the imaging device of this invention. The flowchart for demonstrating the operation | movement at the time of the continuous shooting mode of the digital camera of this embodiment. Diagram showing an example of the structure of an image file The figure which shows an example of the reproduction | regeneration screen of the picked-up image data obtained by continuous shooting The figure which showed the structural example which enables charge mixing with the MOS type solid-state image sensor

Explanation of symbols

5 Solid-state image sensor 10 Image sensor drive unit

Claims (16)

An image pickup apparatus having a solid-state image sensor and a driving unit for driving the solid-state image sensor,
A continuous shooting mode in which a plurality of times of imaging are continuously performed by the solid-state imaging device and a plurality of captured image data obtained by the plurality of times of imaging is recorded can be set.
In the continuous shooting mode, the driving unit changes the driving method of the solid-state imaging device in each of the plurality of times of imaging. The imaging apparatus according to claim 1,
The driving method of the solid-state imaging device for at least one of the plurality of times of imaging mixes the charges accumulated in the photoelectric conversion elements included in the solid-state imaging device, and outputs a signal corresponding to the mixed charges. An imaging device that is charge mixed drive to output. The imaging apparatus according to claim 2,
An imaging apparatus in which the driving means performs imaging by the charge mixing drive at least twice in the continuous shooting mode, and changes the number of charges mixed in each of the charge mixing driving at least twice. The imaging device according to claim 2 or 3,
A signal amplifying means for amplifying a signal output from the solid-state imaging device;
The signal amplification of the signal output from the solid-state imaging device by the charge mixing drive, where α is the amplification factor by the signal amplification means of the signal output from the solid-state imaging device by normal driving without charge mixing An imaging apparatus comprising: an amplification factor control unit configured to control an amplification factor β by the unit to β = α / n, where n is the number of charges mixed in the charge mixture driving. The imaging device according to claim 2 or 3,
Assuming that the exposure determined at the time when the shooting instruction is given in the continuous shooting mode is α, the exposure β when performing the charge mixing drive is set to n as the number of charges mixed in the charge mixture driving. An imaging apparatus comprising exposure control means for controlling β = α / n. The imaging apparatus according to any one of claims 2 to 5,
An imaging apparatus in which the driving means performs the multiple times of imaging by the charge mixing driving and normal driving without mixing charges, and performs the charge mixing driving before the normal driving. The imaging apparatus according to claim 6,
The drive means performs the plurality of times of imaging by the charge mixing drive and the normal drive at least twice, and the charge mixing drive at least twice is performed in descending order of the number of charges mixed. An imaging device. The imaging apparatus according to any one of claims 2 to 5,
An imaging apparatus in which the driving unit performs the plurality of times of imaging only by the charge mixing driving, and performs the charge mixing driving in descending order of the number of charge mixing. The imaging device according to any one of claims 2 to 8,
A recording means for recording on a recording medium an image file composed of captured image data obtained by the charge mixing drive and attached information on the captured image data;
The recording device records information on the number of charges mixed in the charge mixture drive in the attached information of the captured image data. The imaging device according to any one of claims 2 to 8,
A recording means for recording, on a recording medium, an image file composed of a plurality of captured image data obtained by the plurality of times of imaging and attached information regarding each of the plurality of captured image data;
The image recording apparatus, wherein the recording unit records information on the number of charges mixed in the charge mixing drive in the attached information of the captured image data obtained by the charge mixing drive among the plurality of photographed image data. The imaging apparatus according to any one of claims 1 to 10,
When displaying an image based on the captured image data on a display unit, the image processing apparatus includes display control means for displaying together with the image a parameter related to noise of the captured image data and a parameter related to resolution,
When the parameters related to noise and the parameter related to resolution of the captured image data generated based on the signal output from the solid-state image sensor by normal driving without mixing of charges are X and Y, respectively, the charge A parameter relating to noise and a parameter relating to resolution of captured image data generated based on a signal output from the solid-state imaging device by mixing driving, where n is the number of charges mixed in the charge mixing driving, Imaging devices in which x = n * X and y = Y / n, respectively. The imaging apparatus according to any one of claims 1 to 10,
Comprising signal processing means for performing signal processing on a signal output from the solid-state imaging device;
The image processing apparatus, wherein the signal processing unit performs signal processing on the signal in accordance with a driving method performed to obtain the signal. The imaging apparatus according to claim 12,
For the signal output from the solid-state imaging device by the charge mixing drive, the signal processing unit is configured so that the number of pixels of captured image data generated from the signal is a preset number of recording pixels. An imaging apparatus that performs processing for reducing or enlarging photographed image data generated from the signal. The imaging apparatus according to any one of claims 1 to 13,
An imaging apparatus capable of selecting and recording arbitrary image data from a plurality of photographed image data obtained by the plurality of times of imaging. The imaging apparatus according to any one of claims 1 to 14,
An imaging apparatus in which the solid-state imaging device is a CCD solid-state imaging device. The imaging apparatus according to any one of claims 1 to 14,
An imaging apparatus in which the solid-state imaging device is a MOS solid-state imaging device.

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