JP2003078820A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate fixed pattern noise that occurs in an imaging device of an electronic camera with high accuracy even though fluctuations of an environment are large in an imaging mode. SOLUTION: Noise data are acquired both before and after imaging an object, and correction processing of the fixed pattern noise is also performed on the basis of the two pieces of noise data. As a result, it is possible to eliminate the fixed pattern noise with high accuracy.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera having a noise removing function for removing fixed pattern noise (described later).

[0002]

2. Description of the Related Art Usually, when a dark object such as a night sky is photographed by a camera, a long exposure with a slow shutter speed (exposure time of 1/15 seconds to several tens of seconds) is required. . When long-time exposure is performed with an electronic camera that uses an image sensor instead of film, fixed pattern noise (white spots or bright spots) on the acquired image may occur due to variations between pixels of the image sensor. In the specification, a phenomenon that "fixed pattern noise" is simply generated occurs. In particular, when shooting a starry sky, the star that is the actual pattern resembles this fixed pattern noise, so
The effect on the image is large.

Therefore, in recent years, one of the additional functions of electronic cameras has been introduced.
As one, a noise removal function was proposed. The noise removal function drives the image sensor with the shutter closed, regards the image data obtained at that time as data indicating fixed pattern noise (hereinafter referred to as "noise data"), and uses this noise data as the subject. Is corrected to obtain a high-quality image from which fixed pattern noise has been removed.

This fixed pattern noise is unique to each electronic camera, and even if it occurs in the same electronic camera, it changes depending on the environment at the time of image pickup. It was executed every time an image was taken.

[0005]

However, even with such a noise removing function, if the environment changes at the time of imaging, the noise removing accuracy cannot be sufficiently obtained, and the image quality cannot be improved. The quality of the image was sometimes degraded.

Therefore, a first object of the present invention is to provide an electronic camera capable of removing fixed pattern noise with high accuracy even if there is a large change in environment during image pickup. By the way, in a general electronic camera, the noise removal function can be set and released, and when the shutter speed becomes slower than a predetermined speed (for example, exposure time T ≧ 1/15 seconds or more). Only when the setting is valid.

However, once the noise removal processing is started when the setting of the noise removal function is effective, there is a waiting time for the operator to take an image until the noise removal is completed. Therefore, conventionally, the operator may miss a photo opportunity due to the noise removal function.

Therefore, a second object of the present invention is to provide an electronic camera capable of immediately switching the priorities of fixed pattern noise removal processing and imaging processing in response to a request from an operator. .

[0009]

An electronic camera according to a first aspect of the present invention includes an image pickup device for picking up an image of a subject, a shutter unit for opening and closing an incident optical path of the image pickup unit, the image pickup unit and the shutter unit. And a control unit for driving and controlling the image pickup device, wherein the control unit drives the image pickup device in a state in which the incident optical path is opened with respect to the shutter unit and acquires image data indicating an image of the subject. And a noise data acquisition procedure for acquiring noise data indicating fixed pattern noise by driving the image sensor in a state where the incident optical path is closed with respect to the shutter means, and noise data acquired by the noise data acquisition procedure. And an image correction procedure for correcting fixed pattern noise of the image data acquired by the image pickup procedure, based on The size data acquisition procedure, and executes in both before and after execution of the imaging procedure and execution,
It is characterized in that the correction in the image correction procedure is performed based on the two noise data acquired by the noise data acquisition procedure.

As described above, if the fixed pattern noise correction processing is performed based on the two noise data obtained before and after the image pickup of the object, the fixed pattern noise can be obtained with high accuracy even if the environment changes at the time of image pickup. Noise can be removed. The electronic camera according to claim 2 is the electronic camera according to claim 1, wherein the control unit indicates the exposure time of the image sensor in the image capturing procedure by the brightness of the subject and / or an instruction from an operator. And the charge accumulation time of the image sensor in the noise data acquisition procedure is set to be the same as the exposure time.

According to a third aspect of the present invention, there is provided an electronic camera according to the first aspect.
Alternatively, the electronic camera according to claim 2, further comprising an imaging man-machine interface unit that receives an instruction to start execution of the imaging procedure from an operator, and the control unit includes the noise data acquisition procedure, the imaging procedure, and the noise. It is characterized in that a series of procedures including a data acquisition procedure is executed immediately after the start instruction is accepted.

An electronic camera according to a fourth aspect is the electronic camera according to the first aspect.
Alternatively, the electronic camera according to claim 2, further comprising: an imaging man-machine interface unit that receives a start instruction to execute the imaging procedure from an operator, and the control unit receives the start instruction for the noise data acquisition procedure. It is characterized in that it is continuously executed earlier, and a series of procedures including the imaging procedure and the noise data acquisition procedure is executed immediately after receiving the start instruction.

An electronic camera according to a fifth aspect of the present invention is an image pickup device for picking up an image of a subject, a shutter unit for opening and closing an incident optical path of the image pickup unit, and a control unit for driving and controlling the image pickup unit and the shutter unit. And the image pickup procedure for driving the image pickup device in a state where the incident optical path is opened with respect to the shutter unit to obtain image data showing an image of the subject, and the shutter unit. On the other hand, based on the noise data acquired by the noise data acquisition procedure of driving the imaging device with the incident optical path closed to acquire noise data indicating fixed pattern noise, and the noise data acquired by the noise data acquisition procedure, the imaging is performed. An image correction procedure for correcting fixed pattern noise of image data acquired by the procedure is executed, and the operator gives an instruction to stop the correction. Further comprising a canceling man-machine interface means for accepting the cancel instruction, and the control section cancels the execution when the cancel instruction is accepted during execution of the noise data acquisition procedure and / or the image correction procedure. And

That is, the priority of the fixed pattern noise removal processing and the image pickup processing can be immediately switched according to the operator's request. The electronic camera according to claim 6 is the electronic camera according to claim 5, further comprising imaging man-machine interface means for receiving an instruction to start execution of the imaging procedure from an operator, and the cancellation man-machine interface. The same operation member as that of the imaging man-machine interface is also used.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3 and 4. FIG. 1 is an external view of the electronic camera of this embodiment. FIG. 1A is a view of the electronic camera viewed from above, and FIG. 1B is a view of the electronic camera viewed from the rear (operator side).

As shown in FIG. 1A, on the upper surface of the electronic camera 1, a main switch 4 for turning on / off a power source, a release button 5, and a switching operation between a recording mode and a reproduction mode. A dial 6 for performing the operation, a display panel 7 for displaying camera information, and the like are provided. Further, in FIG. 1, reference numeral 2 is a photographing optical system. Here, the “recording mode” refers to a mode of the electronic camera 1 capable of shooting a subject image and recording the image data thereof. In the recording mode, the image of the subject currently captured by the photographing optical system 2 (through image) is displayed on the display LCD 3 (FIG. 1) provided on the rear surface of the camera.
(See (b)).

The "reproduction mode" refers to a mode of the electronic camera 1 which reproduces and displays an image recorded in the past on the display LCD 3. Further, as shown in FIG. 1B, on the rear surface of the electronic camera 1, in addition to the display LCD 3 for image display,
A viewfinder eyepiece window 8 and a zoom switch button 9 for zooming the photographing optical system 2 are also provided.

FIG. 2 is a block diagram illustrating the configuration of the electronic camera 1 of this embodiment. As shown in FIG. 2, the electronic camera 1 includes various optical systems (reference numerals 2, 214, etc.) and various man-machine interfaces (reference numerals 13, 5, 10, 6,).
11, 9, 12, 4, 3, 3, 462, etc.), various mechanisms (reference numerals 408, 415 etc.), various circuits (reference numeral 43)
1,432,433,436,430,454,45
3,434,435,439,443,445,44
8,440, etc.) are provided.

Each unit of the electronic camera 1 operates under the control of the CPU 439. Electronic camera 1 by CPU439
The control program of is stored in the ROM 443 in advance.
When the main switch 4 is turned on, the electronic camera 1 is turned on and this control program is started by the CPU 439. Hereinafter, each unit that operates under the control of the CPU 439 will be described.

When the recording mode is set by the dial 6, the image data of the through image based on the signal output from the CCD image pickup device (CCD) 214 is sent to the display LCD 3 via the frame memory 435, and
Imaging (described later) by operating the release button 5 is possible.
Also, when the reproduction mode is set by the dial 6, the image data recorded in the memory card 424 is read by the digital signal processor (DSP) 433, and the display L is displayed via the frame memory 435.
The image is reproduced and displayed on the CD3.

The operation relating to image pickup and acquisition of noise data in the recording mode will be described below. The focus adjustment of the photographing optical system 2 is performed by the lens drive circuit 4 according to the focus adjustment state detected by the output signal from the CCD 214.
30 is performed by moving the lens in the photographing optical system 2.

Incidentally, the operation of this focus adjustment is usually C
Although it is performed under the control of the PU 439, the operation signal output when the range ring 462 is manually operated also
It can be done. The aperture drive circuit 453 sets the stepper motor 415 to set the aperture stop of the photographing optical system 2.
It is performed by driving the aperture stop 215 in the photographing optical system 2 via.

To set the shutter speed (exposure time), the shutter drive circuit 454 sets the step motor 408.
The shutter plate 208 in the photographing optical system 2 is driven via
This is done by closing or opening the light path. In particular, when capturing an image of a subject, unnecessary electric charges accumulated in the CCD 214 are discharged and the aperture value of the aperture stop 215 is set while the optical path is opened by the shutter plate 208. At this time, since the CCD 214 is exposed, the charge indicating the subject is accumulated in the CCD 214. After a lapse of time, the shutter plate 208 closes the optical path and the charge is discharged from the CCD 214.

At this time, the exposure time T of the CCD 214 is
It is the time from the discharge of the unnecessary charges to the closing of the optical path. On the other hand, when acquiring the noise data, the CCD 214 is used with the optical path closed by the shutter plate 208.
Unnecessary charges accumulated in are discharged. CC at this time
Since D214 is not exposed, only charges showing fixed pattern noise are accumulated in the CCD214. After the lapse of time, the charge is discharged from the CCD 214.

At this time, the charge accumulation time T'of the CCD 214 is the time from the preceding unnecessary charge discharge to the subsequent charge discharge. In the above description, the exposure time T
Is set according to the timing of opening / closing the shutter plate 208 and C
Although it is assumed that it is performed in combination with the driving timing of the CD 214, it may be performed by only one of them.

The CCD 214 is supplied with a horizontal drive signal from a digital signal processor (DSP) 433 and a vertical drive signal from a CCD drive circuit 434 controlled by the DSP 433. That is,
The CCD 214 is a DSP 433 and a CCD drive circuit 43.
4, the timing is controlled. A signal from the CCD 214, that is, image data of a subject, image data such as noise data, is input to the image processing unit 431. The image processing unit 431 has a DC generation circuit and the like, and
Analog processing such as gain control is performed on the image signal output from D214.

The analog image data output from the image processing unit 431 is analog / digital conversion circuit (A /
D conversion circuit) 432 converts into a digital signal. The converted digital image data is input to the DSP 433. The DSP 433 performs predetermined image processing such as contour compensation, γ correction, and white balance adjustment on the digital image data.

Further, the DSP 433 is a buffer memory 4
The data bus connected to the memory card 36 and the memory card 424 is controlled to temporarily store the image data subjected to various image processing in the buffer memory 436. Buffer memory 4
For the image data stored on the CPU 36, the CPU 43
Image data to be recorded is generated by performing a correction process (described later) and the like by 9.

The DSP 433 reads out image data to be recorded from the buffer memory 436, compresses the data in a predetermined compression format (for example, JPEG method) to form a compressed file, and stores it in the memory card 424.
Incidentally, the DSP 433 can also display the image data after being imaged by the CCD 214 and subjected to the image processing on the display LCD 3 via the frame memory 435.

Further, the DSP 433 also manages timing of data input / output in recording in the memory card 424 and recording in the buffer memory 436 described above.
It should be noted that the buffer memory 436 is configured such that the input / output speed of image data to / from the memory card 424 is different, and the CPU 43
9 and DSP433 are used to reduce the difference in processing speed.

Here, the buffer memory 43 of this embodiment is used.
The reference numeral 6 has a capacity sufficient for the CPU 439 to perform at least correction processing (described later) based on three image data, which will be described later, first noise data, subject image data, and second noise data. And In addition, a part or all of the operation by the DSP 433 described above is performed by the CPU.
It can also be performed by 439. DSP433 and CPU
The reason why the processing is shared with 439 is to improve the processing efficiency.

Further, in FIG. 2, reference numeral 445 has a built-in clock circuit, and the time data for the current time is CP.
A reference numeral 448 is an interface for outputting data to and from the CPU 439 and the external device by connecting a predetermined external device (not shown), and a reference numeral 440 is an electronic camera 1. It is a display circuit for displaying the setting contents in the display panel 7.

FIG. 3 shows the CPU 439 in this embodiment.
3 is an operation flowchart of FIG. Note that this operation flowchart is started when the recording mode is set in the electronic camera 1. C between the recording mode and the reproduction mode and when the reproduction mode is set
Since the operation of the PU 439 is the same as the conventional one, its explanation is omitted.

When the release button 5 is pressed halfway (step S1 YES), photometry and the exposure time T based on the photometry are calculated (step S2). Metering: Release button 5
The brightness of the subject is measured based on the output signal of the CCD 214 when is pressed halfway. The exposure time T is calculated according to the brightness of the subject. Also,
In step S2, the aperture stop 215 is set together with the exposure time T.
The aperture value of is also calculated according to this brightness.

Thereafter, when the release button 5 is fully pressed (YES in step S3), the calculated exposure time T is compared with the predetermined value T0 (step S4). Here, when the calculated exposure time T is shorter than the predetermined value T0 (for example, 1/15 second) (step S4 NO), removal of fixed pattern noise is considered unnecessary, and normal imaging (exposure time T Imaging of the subject below and recording of image data) is performed (step S5).

However, the calculated exposure time T is the predetermined value T
When it is determined that the image pickup of the subject is longer than 0 and the exposure is for a long time (YES in step S4), removal of fixed pattern noise is considered necessary, and the following processing is executed. Also in this long-time exposure, image pickup is performed under the calculated exposure time T and image data of the subject is acquired (step S7).

However, in this embodiment, the first noise data is acquired under the charge accumulation time T'before the image pickup of the subject (step S6). Here, the charge accumulation time T '
Is set to the same length as the exposure time T. This is because the noise data can be obtained with higher accuracy as the condition for obtaining the noise data is closer to the condition for capturing the image.

Acquisition of first noise data (step S6)
When the imaging of the subject (step S7) is executed, the second noise data is subsequently acquired in the present embodiment (steps S9 to S11). Here, the charge accumulation time T ′ when acquiring the second noise data is also set to the same value as when acquiring the first noise data.

The exposure start for imaging the subject is
Immediately after the first noise data is acquired, that is, immediately after the first noise data is stored in the buffer memory 436. The charge accumulation for obtaining the second noise data is started immediately after the image data of the subject is obtained, that is, immediately after the image data of the subject is stored in the buffer memory 436.

When the first noise data, the image data of the subject, and the second noise data are acquired in this way (step S11 YES), the correction process is executed (step S12). FIG. 4 is a diagram for explaining the correction process in this embodiment. In the figure, the number of pixels is smaller than the actual number for the sake of clarity.

In the first noise data shown in FIG. 4A,
Although most of the pixel values are 0, the pixel value at the point p is 127 and the pixel value at the point q is 255. This is the fixed pattern noise generated when the first noise data was acquired. The image data shown in FIG. 4B is image data showing a subject, on which fixed pattern noise is superimposed.

In the second noise data shown in FIG. 4C, most of the pixel values are 0, but the pixel value at the point p is 255, the pixel value at the point q is 255, and the point r. The pixel value at is 56. This is the fixed pattern noise generated when the second noise data was acquired. As is apparent from the comparison between FIGS. 4A and 4C, it can be seen that the fixed pattern noise changes before and after the imaging of the subject. The brightness of the bright spot at the point p is high, and at the position of the point r, a bright spot that was not present before the imaging occurs after the imaging.

In the conventional electronic camera, the fixed pattern noise is removed with a low accuracy because the environment at the time when the noise data is acquired is significantly changed from the environment at the time of capturing the image of the object. It is considered that the fixed pattern noise that actually occurred at the time of image capturing was not accurately displayed. In the present embodiment, noise data (first noise data and second noise data) is acquired before and after image capturing, so in the correction process here, the fixed pattern noise that should have occurred at the time of image capturing The estimation is performed based on two pieces of noise data (first noise data and second noise data).

The estimation is performed when the first noise data is acquired and the second noise data is acquired.
Taking the average of these two noise data, it is assumed that the noise data is acquired at the same time as the time when it is captured and the fixed pattern noise changes linearly with time. Done by. That is, the first noise data Dn1 and the second noise data Dn2
On the other hand, the fixed pattern noise Dn at the time of imaging is D
It is estimated by the formula of n = (Dn1 + Dn2) / 2.

FIG. 4D shows the estimated fixed pattern noise. The estimated fixed pattern noise is
The pixel value 191 at the point p and the pixel value 25 at the point q
5 and the pixel value 28 at the point r. Then, the correction is performed by subtracting the estimated fixed pattern noise from the image data of the subject.

That is, with respect to the image data D before correction and the fixed pattern noise Dn, the corrected image data D ′ is
It is obtained by the formula of D ′ = D−Dn. As shown in FIG. 4E, fixed pattern noise is removed from the corrected image data. Returning to FIG. 3, when the above correction process is completed (step S14 YES), the corrected image data is recorded as the image data to be recorded (step S15).

Here, since the image data is recorded on the memory card 424 (see FIG. 2), at the time of recording,
A file for recording is created by performing compression processing or the like on the image data. Subsequent imaging is possible at the time when this recording file is created in the buffer memory 436.

Therefore, the determination in step S1 is executed again when this file is created. As described above, in the present embodiment, noise data is acquired both before and after imaging, and fixed pattern noise correction processing is performed on the basis of the two noise data, so there is a large change in the environment during imaging. In both cases, fixed pattern noise can be removed with high accuracy.

By the way, in the electronic camera 1 of the present embodiment, each processing relating to the removal of fixed pattern noise described above can be appropriately interrupted by the operator operating the release button 5. That is, as shown in FIG. 3, in the electronic camera 1, if the release button 5 is half-depressed after the imaging of the subject is performed (step S7) (step S8 YES), the above-mentioned second noise is generated. The image data before correction obtained by the image pickup is recorded without executing the data acquisition process (step S9) (step S16).

Then, when a recording file based on this image data is created in the buffer memory 436, the next image pickup is possible. Therefore, when the operator wants to immediately start the next image capturing rather than removing the fixed pattern noise when the release button 5 is fully pressed and the first image capturing is performed, Release button 5
Press halfway.

Further, in the electronic camera 1, if the release button 5 is pressed halfway while the second noise data is being acquired (after execution of step S9 until YES is obtained in step S11). (Step S10 YES), the acquisition of the second noise data is interrupted, and the image data before correction is immediately recorded (step S16). Then, when a recording file based on this image data is created in the buffer memory 436, the next image pickup is possible.

Further, in the electronic camera 1, if the release button 5 is half-depressed while the correction process is being executed (after execution of step S12 until YES is obtained in step S14) ( (YES in step S13), the correction process is interrupted, and the image data before correction is immediately recorded (step S16). Then, when a recording file based on this image data is created in the buffer memory 436, the next image pickup is possible.

Therefore, when the operator desires to immediately start the next image pickup rather than removing the fixed pattern noise after the first image pickup by pressing the release button 5 fully. , The release button 5 should be pressed halfway.
As described above, in the present embodiment, it is possible to immediately switch the priority of the fixed pattern noise removal processing and the imaging processing according to the operator's request.

Moreover, since the switching is performed by the operation of the release button 5 for picking up an image of the subject, the operator does not have to release the hand from the release button 5 for this switching. That is, the priority switching between the fixed pattern noise removal processing and the imaging processing is performed with good operability. In this embodiment, when the process of removing fixed pattern noise is interrupted (steps S8 and S in FIG. 3).
Although the uncorrected image data D is recorded in S10, S13 YES), the first noise data Dn1 is recorded.
The image data may be corrected based on only (in this case, the corrected image data D ′ is D ′ = D−D
It is obtained by the formula of n1. ).

When this correction is performed, the waiting time until the next image pickup becomes possible is longer than that described above by the amount of the correction. Incidentally, the removal precision of fixed pattern noise in this case is the same as the conventional one. Further, in the present embodiment, the charge storage time T ′ when acquiring noise data is set to be the same as the exposure time T when the subject is imaged, but even if the removal precision of fixed pattern noise is sacrificed to some extent. , If it is desired to shorten the time for removing fixed pattern noise, the charge accumulation time T ′ is set to T / α (where α>
It may be set to 1). In this case, the equation for estimating the fixed pattern noise Dn in the correction process is Dn = α
× (Dn1 + Dn2) / 2.

In particular, if α = 2, the equation for estimating the fixed pattern noise becomes Dn = Dn1 + Dn2, which simplifies the calculation. By the way, the charge storage time is T / α
(However, when α> 1), the process of removing fixed pattern noise is interrupted (step S8 in FIG. 3,
If the correction based on only the first noise data Dn1 is performed in S10 and S13 YES), the corrected image data D '
Is obtained by the formula of D ′ = D−α × Dn1.

Needless to say, in the present embodiment, the procedure for interrupting each process relating to the removal of fixed pattern noise (steps S8, S10, S11, S).
13, S14, S16) can be omitted.
Needless to say, the process for this interruption (steps S8, S10, S11, S13, S14, S16)
Can be performed in a conventional electronic camera (that is, the correction process is performed based on only single noise data).

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIGS. 1, 2 and 5. Here, only the differences from the first embodiment will be described. The external appearance and configuration of the electronic camera of this embodiment are shown in FIG.
This is the same as the electronic camera 1 of the first embodiment shown in FIG.
The content of the correction process is also the same as in the first embodiment. However, the content of the operation by the CPU 439 is partially different (that is, the content of the program stored in advance in the ROM 443 is partially different).

FIG. 5 shows the CPU 439 in this embodiment.
3 is an operation flowchart of FIG. 5, the same steps as those shown in FIG. 3 are designated by the same reference numerals. As is clear from the comparison between FIG. 5 and FIG. 3, in the present embodiment, the process of acquiring the first noise data (step S
6) is before the release button 5 is fully pressed.

That is, in this embodiment, the release button 5
Is pressed halfway (YES in step S1), the exposure time T is calculated (step S2), and then the exposure time T is set to a predetermined value T.
When it is shorter than 0 (step S4 NO), normal imaging (step S5) is executed in response to the release button 5 being fully pressed (step S3 YES), but the exposure time T is longer than the predetermined value T0. When it is long (step S4 YES),
Even if the release button 5 is not fully pressed, the first noise data is acquired (step S6).

In the present embodiment, the acquisition of the first noise data (step S6) is a period in which the release button 5 is half-pressed and not fully pressed (step S3NO), and is calculated. During the period in which the exposure time T is longer than the predetermined value T0 (YES in step S4), the exposure is repeated. Note that it is unknown to the electronic camera 1 which information is repeatedly acquired at which timing the subject is imaged (whether the release button 5 is fully pressed). Therefore, the latest first noise data is always stored in the buffer memory. Four
This is because it is necessary to have it on 36.

Therefore, even if the first noise data is repeatedly acquired, only the latest one is stored in the buffer memory 436 (the acquired first noise data is stored in the buffer memory 436). Will be overwritten sequentially). With this configuration, the electronic camera 1 according to the first embodiment
Compared with, the time from when the release button 5 is pressed halfway to when the release button 5 is fully pressed to enable image capturing is longer, but fixed pattern noise is removed after the release button 5 is fully pressed. Since it is possible to shorten the time until the image data is obtained, the possibility that the operator misses the next photo opportunity is suppressed.

<Others> In each of the above embodiments, the correction processing is executed by the CPU 439, but it is also possible to cause the DSP 433 to execute some or all of the correction processing. Also, an electronic camera capable of performing both the operation described in the first embodiment and the operation described in the second embodiment can be configured.

Further, when the noise removal mode can be set and released in the electronic camera 1 in each of the above-described embodiments, the above-mentioned processing relating to the removal of fixed pattern noise (steps S4, S6 to S16 in FIGS. 3 and 5).
Is executed only when the noise reduction mode is set. Further, when the continuous shooting mode can be set and released in the electronic camera 1 in each of the above-described embodiments, the above-described processing related to the removal of fixed pattern noise (steps S4, S6 to S16 in FIGS. 3 and 5) is not performed. , Is executed only when the continuous shooting mode is canceled. This is to keep the number of imaged frames per unit time high when the continuous shooting mode is set.

Further, when the electronic camera 1 in each of the above-described embodiments is provided with the stroboscopic light emission function, the above-described processing relating to the removal of fixed pattern noise (steps S4, S6 to S16 in FIGS. 3 and 5) is not performed. , It is executed only when the flash is not fired. This is because the noise generated during strobe emission cannot be properly removed by this processing, unlike the fixed pattern noise described above.

[0066]

As described above, according to the present invention,
The fixed pattern noise is removed with high accuracy even if there is a large change in the environment during imaging. Further, according to the present invention, the priorities of the fixed pattern noise removal processing and the imaging processing can be immediately switched in response to the operator's request.

[Brief description of drawings]

FIG. 1 is an external view of an electronic camera according to first and second embodiments. FIG. 1A is a view of the electronic camera viewed from above, and FIG. 1B is a view of the electronic camera viewed from the rear (operator side).

FIG. 2 is an electronic camera 1 according to the first and second embodiments.
2 is a block diagram illustrating the configuration of FIG.

FIG. 3 is an operation flowchart of a CPU 439 according to the first embodiment.

FIG. 4 is a diagram illustrating a correction process in the first embodiment and the second embodiment.

FIG. 5 is an operation flowchart of a CPU 439 according to the second embodiment.

[Explanation of reference numerals] 1 electronic camera 2 photographing optical system 3 display LCD 4 main switch 5 release button (corresponding to image capturing man-machine interface means and cancel man-machine interface means) 6 dial 7 display panel 8 viewfinder eyepiece window 9 zoom switching Button 10 Menu button 11 Select button 12 Mode switching button 13 Focus mode buttons 201, 202, 203, 204 Lens 208 Shutter plate (corresponding to shutter means) 215 Aperture stop 214 CCD image sensor (CCD) (corresponding to the image sensor in claims) ) 408, 415 Step motor 431 Image processing unit 432 Analog / digital conversion circuit (A / D conversion circuit) 433 DSP 435 Frame memory 436 Buffer memory 424 Memory card 430 Lens drive circuit 434 CCD drive circuit 439 CPU (corresponding to control unit) 440 Display circuit 443 ROM 445 Timer 448 Interface 453 Aperture drive circuit 454 Shutter drive circuit 462 Distance ring

Claims (6)

[Claims] 1. An image pickup device for picking up an image of an object, a shutter unit for opening and closing an incident optical path of the image pickup unit, and a control unit for driving and controlling the image pickup device and the shutter unit. An image pickup procedure in which the image pickup device is driven in a state in which the incident light path is opened with respect to the shutter means, and image data showing an image of the subject is acquired; In the state where the image sensor is driven, noise data acquisition procedure for acquiring noise data indicating fixed pattern noise, and fixing of image data acquired by the imaging procedure based on the noise data acquired by the noise data acquisition procedure An image correction procedure for correcting pattern noise, and performing the noise data acquisition procedure and the imaging procedure. An electronic camera that is executed both before and after execution, and that the correction in the image correction procedure is performed based on two noise data acquired by the noise data acquisition procedure. 2. The electronic camera according to claim 1, wherein the control unit sets an exposure time of the image pickup device in the image pickup procedure according to the brightness of the subject and / or an instruction from an operator. At the same time, the electronic camera is characterized in that the charge accumulation time of the image pickup device in the noise data acquisition procedure is set to be the same as the exposure time. 3. The electronic camera according to claim 1, further comprising: an imaging man-machine interface unit that receives an instruction to start execution of the imaging procedure from an operator, and the control unit includes the noise data acquisition. An electronic camera, characterized in that a series of procedures including a procedure, the imaging procedure, and the noise data acquisition procedure is executed immediately after the start instruction is accepted. 4. The electronic camera according to claim 1, further comprising an imaging man-machine interface unit that receives an instruction to start execution of the imaging procedure from an operator, and the control unit includes the noise data acquisition. An electronic device characterized in that the procedure is continuously executed before the start instruction is accepted, and a series of procedures including the imaging procedure and the noise data acquisition procedure is executed immediately after the start instruction is accepted. camera. 5. An image pickup device for picking up an image of a subject, a shutter unit for opening and closing an incident optical path of the image pickup unit, and a control unit for driving and controlling the image pickup device and the shutter unit. An image pickup procedure in which the image pickup device is driven in a state in which the incident light path is opened with respect to the shutter means, and image data showing an image of the subject is acquired; In the state where the image sensor is driven, noise data acquisition procedure for acquiring noise data indicating fixed pattern noise, and fixing of image data acquired by the imaging procedure based on the noise data acquired by the noise data acquisition procedure An image correction procedure for correcting pattern noise is executed, and a canceling command for canceling the correction is received from the operator. Further comprising a thin interface means, wherein, during execution of the noise data acquisition procedure and / or the image correction procedures, upon receiving the stop instruction, an electronic camera, characterized in that to stop its execution. 6. The electronic camera according to claim 5, further comprising: an imaging man-machine interface unit that receives an instruction to start execution of the imaging procedure from an operator, and the cancel man-machine interface includes the imaging man-machine. An electronic camera characterized in that the same operation member as the machine interface is also used.