JP2001008091A - Image pickup device and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an image pickup device by which a photographer can obtain a picture with a shorter exposure time than the exposure time of the picture whose exposure time is felt too much by the photographer in the case of photographing in a high sensitivity mode. SOLUTION: In the case that exposure of a solid-state image pickup element 101 is updated for each prescribed reference period, a memory 108 stores image data obtained from the solid-state image pickup element 101 for the first one reference period after starting the exposure, an adder 107 sums the image data obtained from the solid-state image pickup element 101 for the next one reference period and the image data having been stored in the memory 108, a memory 109 stores the sum, and similarly the adder 107 sums the image data obtained from the solid-state image pickup element 101 for the one reference period next to the next one reference period and the image data having been stored in the memory 109 sequentially and the member 108 stores the sum as its control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus for photographing a subject using an image pickup device and a control method thereof, and more particularly to an image pickup apparatus having a high sensitivity photographing mode and a control method thereof.

[0002]

2. Description of the Related Art Conventionally, when performing high-sensitivity photographing with a digital camera using an image pickup device such as a solid-state image pickup device, a solid-state image pickup device capable of controlling the exposure time is used, and the exposure time is set to a plurality of reference periods. A slow shutter control circuit with a take-out time of one reference period is provided, and the taken-out image signal is stored in the image memory, and during the next exposure time, the same image signal previously stored in the image memory is repeatedly read out, thereby achieving a small and high sensitivity. Digital camera.

[0003] Such an imaging device will be described with reference to the drawings.

FIG. 4 is a block diagram showing a configuration of a conventional example. In FIG. 4, reference numeral 201 denotes a solid-state image sensor which is an image sensor, and the solid-state image sensor 201 is known to be of a MOS type, a CCD type, or the like. A description will be given using an apparatus having a so-called electronic shutter function that can control the exposure time by manipulating the sweep timing and the like.

The image sensor control circuit 202, high-speed shutter timing generator 203, and reference oscillator 204
This is a circuit for driving and controlling the solid-state imaging device 201 having an electronic shutter function. An image signal output from the solid-state image sensor 201 is converted into an image signal by a camera signal processing circuit 205.

The slow shutter control circuit 220 operates from 1/6 second to 1/30 longer than one reference time (for example, 1/60 second).
This is a circuit for setting the shutter speed to about second. This circuit includes a mode circuit 211, a shutter switching circuit 212, and a low-speed shutter timing generator 213.

[0007] The image memory unit 221 is a circuit that stores the image signal from the camera signal processing circuit 205 and can read the image signal a required number of times for each reference period. This circuit includes an A / D converter 215, an image memory (field memory) 216, a memory controller 218, a D / A converter 217, and the like.

[0008] The memory controller 218 is an image memory 2
16 is a circuit for controlling a clock and a control signal for writing or reading. The switching signal of the switching circuit 210 is also generated from this circuit.

A clock and control signal generation circuit 214 obtains a timing pulse from the slow shutter control circuit 220 and takes out a continuous image signal even during a slow shutter operation, such as time control of memory writing or reading of the image memory unit 221. It is responsible for generating clock and control signals.

The switching circuit 210 is a switch circuit for switching between sending the output of the camera signal processing circuit 205 directly to the recording signal processing circuit 206 and sending the output from the image memory unit 221.

FIG. 5 is a timing chart showing the operation of the conventional example. The detailed configuration and operation will be described below with reference to FIGS. When the solid-state imaging device 201 uses, for example, an interline CCD, a video signal in a reference period is often output using a field retrace period. One reference period is often one field of a normal television signal (period V shown in FIG. 5), that is, 1/60 second, and the shutter speed is naturally 1/6.
0 seconds is common.

In the case of having an electronic shutter function, in the high-speed shutter, the signal charge storage time from once sweeping out the signal charges in the light receiving portion of the solid-state imaging device 201 to emptying and starting the transfer is made shorter than 1/60 seconds. It is often realized by discarding excess charge.

The slow shutter control circuit 220 of this embodiment
Low-speed shutter timing generator 213
It is important that the operation is completely opposite to that of the high-speed shutter timing generator 203 in terms of concept. That is, charge is not transferred for a plurality of reference periods, and charges are successively accumulated in a light receiving portion for a plurality of reference periods (a period nV (n is a positive integer of 2 or more) shown in FIG. 5), and then charges for signal extraction are obtained. The transfer is in progress.

As a method of controlling the exposure time, even when using an image pickup device in which the timing of discharging the surplus signal charge is changed, the signal charge transfer pulse for reading is thinned out so that a plurality of field periods can be continuously applied. Thus, signal charges can be accumulated.

Thus, a shutter that is slower than 1/60 second can be released. Also, even if exposure is performed for a plurality of reference periods, the charge transfer for signal extraction is performed in the same time as the transfer for one reference period, so that one charge is transferred via the camera signal processing circuit 205 without adding a special circuit. Image signals for the period are extracted.

However, according to the above-described means, a blank period occurs until an image signal for the next one reference period is output.
For example, 10 reference periods (1/6 second) (in FIG. 5, n = 1
0) When exposure is performed, a blank period of 9 reference periods occurs. Therefore, the output of the camera signal processing circuit 205 (the output signal M shown in FIG. 5) is sent to the recording signal processing circuit 206 via the switching circuit 210, and is also sent to the image memory unit 221 via the A / D converter 215. The same image signal (the output signal R shown in FIG. 5) is stored in the memory 216 and read out through the D / A converter 217 once every one blank period and one reference period through the switching circuit 210 for recording. The transmission to the signal processing circuit 206 is continued. And L
The image is displayed on the CD 209, and the image signal is stored (recorded medium) by pressing the trigger switch 219.
207.

As described above, the recording signal processing circuit 206 obtains an interpolated image signal in which the same image signal is repeated but there is no blank period during the continuous time required for the exposure.

[0018]

However, in the conventional high-sensitivity imaging apparatus as described above, when the photographer presses the trigger switch 219 at a certain timing to fetch the image signal into the storage 207, the fetched image signal is obtained. Image is LCD
If the image displayed in the image 209 is overexposed when viewed, for example, there is a problem that it is not easy to retake the image.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an image pickup apparatus capable of obtaining an image having a shorter exposure time than the image when the photographer feels that the image has been overexposed. It is an object to provide an apparatus and a control method thereof.

[0020]

An image pickup apparatus and a control method thereof according to the present invention are configured as follows.

(1) In an image pickup apparatus, an image pickup device and first to n-th (n is a positive integer of 2 or more) image data storage means for storing image data obtained by the image pickup device. And adding means for adding the image data obtained by the image sensor and the image data stored in each image data storage means, when the exposure of the image sensor is updated every predetermined period, The image data obtained from the image sensor by the exposure in the first period is stored in the first image data storage means, and the image data obtained from the image sensor by the exposure in the second period is stored in the first image data storage unit. The image data stored in the image data storage unit is added and stored in the second image data storage unit.
The image data obtained by the image pickup device by the exposure during the period of the image and the image obtained by the exposure from the first to the (n-1) th period stored in the (n-1) th image data storage means. The image data to which the data has been added is added and stored in the n-th image data storage means.
, The image data stored in the n-th image data storage means can be arbitrarily read.

(2) In the image pickup apparatus, an image pickup device, first image data storage means for storing image data obtained by the image pickup device, and image data obtained by the image pickup device are stored. A second image data storage unit for storing the image data obtained by the image sensor and the image data stored in the first image data storage unit or the second image data storage unit. Adding means for adding the first image data to the first image data storage means and the second image data storage means, and adding the image data to the first image data storage means and the second image data storage means. Control means for controlling the timing of reading image data from the data storage means, the first image data storage means or the second image data storage means An image selection unit that selects stored image data, a recording medium that records the selected image data, and an image display unit that performs display based on the selected image data. When the exposure is updated every predetermined reference period, the image data obtained from the image sensor in the first reference period after the exposure is started is stored in the first image data storage means, and the next 1 The image data obtained from the image sensor in the reference period and the first
The image data stored in the image data storage means is added to the image data and stored in the second image data storage means. The image data stored in the second image data storage unit is added to the image data, and the added image data is stored in the first image data storage unit.

(3) In the image pickup apparatus of (2), a control switch for recording image data on a recording medium at a desired timing is provided.

(4) In the control method of the image pickup apparatus, first to n-th (n is a positive integer of 2 or more) image data storage means for storing image data obtained by the image pickup device; Addition means for adding the image data obtained by the image sensor and the image data stored in each of the image data storage means is provided, and when the exposure of the image sensor is updated every predetermined period, The image data obtained from the image sensor by the exposure for one period is stored in the first image data storage means, and the image data obtained from the image sensor by the exposure for the second period and the first image are stored. Adding the image data stored in the data storage means to the second
In the image data storage means, and similarly, the image data obtained by the image sensor by the exposure in the n-th period and the first to the (n-1) th image data stored in the (n-1) th image data storage means. The image data obtained by the exposure up to the (n-1) th period is added to the added image data and stored in the n-th image data storage means.

(5) In the control method of the image pickup apparatus, an image pickup device, first image data storage means for storing image data obtained by the image pickup device, and an image obtained by the image pickup device Second for storing data
And adding the image data obtained by the image sensor and the image data stored in the first image data storage or the image data stored in the second image data storage. Adding means; timing for writing image data to the first image data storage means and the second image data storage means;
Control means for controlling the timing of reading image data from the image data storage means and the second image data storage means, and the image stored in the first image data storage means or the second image data storage means. Image selection means for selecting data, a recording medium for recording the selected image data, and image display means for displaying based on the selected image data are provided, and the exposure of the image sensor is set to a predetermined value. When the image data is updated every reference period, the image data obtained from the image sensor in the first reference period after the exposure is started is stored in the first image data storage unit, and the image data is stored in the next reference period. The image data obtained from the image sensor and the image data stored in the first image data storage unit are added and stored in the second image data storage unit. Next, the image data obtained from the image sensor in the next one reference period and the image data stored in the second image data storage unit are added and stored in the first image data storage unit. It was controlled to go.

[0026]

Next, this embodiment will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of the image pickup apparatus according to the present embodiment. In FIG. 1, reference numeral 101 denotes a solid-state imaging device (CCD) as an imaging device, which is connected to a camera signal processing circuit 105 as signal processing means. The A / D converter 106 converts the digital image signal into a digital image signal. The image sensor control circuit 102, the timing generator 103, and the reference oscillator 104 are circuits for driving and controlling the solid-state image sensor 101 having an electronic shutter function.

FIG. 2 is a timing chart showing the operation of the imaging apparatus. As shown in FIG.
01, the image data 0 that has been exposed and read for one reference period (section 0) is output to the camera signal processing circuit 105 and the A / D
The digital signal is converted into a digital signal through a converter 106, and is written into a memory 108 as a first image data storage unit via an adder 107 as an addition unit.

Next, the next 1
The image data 1 exposed during the reference period (section 1) is read out, and the camera signal processing circuit 105 and the A / D converter 1
The signal is converted to a digital signal through the signal line 06. At this time, the image data 0 written one reference period before is read from the memory 108 at the same time, and the pixel data at the same address of the image data 0 and the image data 1 are added by the adder 107 to the second image data. Memory 1 as storage means
09 is written.

The memories 108 and 109 are controlled by supplying a write control pulse, a read control pulse, and the like by a memory controller 110 as image data storage control means. The memory controller 110 receives the synchronization signal and the reference clock pulse from the timing generator 103 and the reference oscillator 104, and generates the above-described write control pulse and read control pulse.

Next, the image data 2 exposed in the next one reference period (section 2) is read out by the solid-state imaging device 101, and the camera signal processing circuit 105 and the A / D converter 10
The signal is converted into a digital signal through 6. Image data 2
The pixel data of the same address as the added data of the image data 0 and the image data 1, which is simultaneously read from the memory 109 and written one reference period earlier, is added to the adder 1.
07 is added to the memory 108 while being added. In this manner, the memory to be written and the memory to be read out are alternately changed every other reference period, and are integrated with the image data from the solid-state imaging device 1 and stored in the memory 108 or the memory 109.

Here, it is assumed that the photographer operates the trigger switch 111 at the timing of t1 to load an image into the storage 117. When the photographer operates the trigger switch 111 at the timing of t1, at the time when the next VD pulse (synchronous signal) is generated, the reading of the image data 2 from the solid-state imaging device 101 is completed, and the image data 0 and the image data 1 are read from the memory 109. The reading of the addition data has been completed, and the writing to the memory 108 has been completed while adding the addition data of the image data 0 and the image data 1 and the image data 2.

When the photographer operates a switch (not shown), an image selection controller 112 serving as image selection means is provided.
And the switching circuit 113 is connected to the A side, and the switching circuit 1
14 is connected to the C side, the image data 3 read out from the solid-state imaging device 101 in the section 3 which is the next one reference period includes the image data 0, the image data 1, and the image data 1 written in the memory 108. The pixel data of the same address as the integrated data of the image data 2 are sequentially stored in the memory 109 while being sequentially added.

At the same time, the data reaches the storage (recording medium) 117 via the switching circuit 113 and the recording signal processing circuit 116, and the integrated data from the image data 0 to the image data 3 is written. Further, the storage 1 is stored in an LCD (liquid crystal display) 119 serving as an image display means via a switching circuit 114, a D / A converter 115, and a monitor signal processing circuit 118.
17, the same image as the integrated image data captured is displayed.

As described above, the VD pulse detected immediately after the trigger switch 111 is operated triggers the storage 1 in one reference section immediately after the VD pulse.
It is easy to think that the timing is set so that the image data is written in 17.

Here, if the photographer wants to monitor the image displayed on the LCD 119 and confirm the image data one reference period before, for example, the image selection controller (not shown) is turned on at time t2 by a switch (not shown). If the switching circuit 114 is connected to D in synchronism with the next VD pulse, the image selecting means 112 is changed from image data 0 to image data 2 which is the integrated image data one reference period earlier.
The integrated image data up to is displayed on the LCD 119.
This image is monitored, and if it is a desired image, the switching circuit 113 is similarly connected to B, and the same integrated image data can be recorded in the storage 117.

Such a case is referred to as an undo mode. In the case of the undo mode, the photographer sets the trigger switch 111 so that the user can return to the integrated image one reference period before.
Is operated, the image data is written into the storage 117 within one section after the detection of the next VD pulse, and further the next VD pulse is detected.
It is preferable that the memory controller 110 operates so that the memory 108 and the memory 109 inhibit the write operation after detecting the D pulse.

The memory controller 110 is set so that reading of the memory 108 or 109 is controlled in accordance with the connection of the switching circuit 113 and the switching circuit 114 selected by the image selection controller 112. Further, in terms of circuit operation, the output of the adder 107 should be fixed at high impedance. Although a specific method of realizing these circuits is not described, all can be realized by conventional circuit design techniques.

The above-described memory writing procedure will be briefly described with reference to the flowchart of FIG. FIG. 3 is a flowchart showing the storage control operation of this embodiment, which is executed by the CPU in the memory controller 110 based on the program stored in the ROM in the memory controller 110.

First, in step S101, the image data 0 in the section 0 of FIG.
When the exposure is updated in step S102, image data 1 in section 1 in FIG.
And the image data 0 read from the memory 108 are stored in the memory 109 while being added.

When the exposure is updated in step S104, the image data 2 in section 2 in FIG. 2 is added to the integrated data of image data 0 and image data 1 read from the memory 109 and stored in the memory 108 in step S105. And continue the same operation.

In this flowchart, the write-inhibiting operation when the trigger switch 111 is pressed is omitted.

Although two memories are used in this embodiment, one memory is naturally divided into two banks, and reading and writing operations to and from the memory are performed at a transfer rate twice or more that of the image data transferred from the solid-state imaging device. , A device having the same effect can be realized.

As described above, in this embodiment, the image pickup device is not driven in the slow shutter mode when performing high-sensitivity photographing, but the image data exposed by the image pickup device for one reference period is divided into two regions. While adding to the image data read from the first image memory of the image memory, the data is written to the other second image memory, and the next 1
In the next one reference period, the image data exposed in the reference period is written to the first image memory while being added to the image data read from the second image memory, and the image exposed by the image sensor on the image memory in the same manner. Data is sequentially added, and image data added for a certain reference period and image data added for one reference period more than the image data are always independently stored in two areas of the image memory. With this configuration, the image data integrated up to that point and the image data integrated up to one reference period earlier can be selectively obtained. The image can be processed by returning to the image before the period.

(Other Embodiments) In the above embodiment, the case where two memories are used has been described.
Is a positive integer of 2 or more).

First, first image data (corresponding to image data 0 in FIG. 2) obtained from the image pickup device by exposure in a first period (corresponding to section 0 in FIG. 2) is stored in a first memory. And the second image data (corresponding to the image data 1 in FIG. 2) obtained from the image sensor by the exposure in the second period (corresponding to the section 1 in FIG. 2) and the first memory The read-out first image data is added and stored in the second memory.

Then, third image data (corresponding to image data 2 in FIG. 2) obtained from the image pickup device by exposure in a third period (corresponding to section 2 in FIG. 2) and a second memory The sum of the product-sum (addition) signal of the first image data and the second image data read from the first image data is added and stored in the third memory.

Subsequently, the fourth image data (corresponding to the image data 3 in FIG. 2) obtained from the image pickup device by the exposure in the fourth period (corresponding to the section 3 in FIG. 2) and the third Adding the sum of products signals from the first image data to the third image data read from the memory and storing the sum in a fourth memory;
... N-th image data (corresponding to image data (n-1) in FIG. 2) obtained from the image sensor by exposure in the n-th period (corresponding to section (n-1) in FIG. 2) And the (n-
From the first image data read from the memory 1) to the (n-1) th image data (the image data (n-2) in FIG. 2).
) Is added and stored in the n-th memory.

As described above, the image data stored in the first memory to the n-th memory can be arbitrarily read, so that the integrated image data in each period (each section) can be selectively read. Can be obtained.

As in the above embodiment, the memory may be divided into n banks and image data may be read and written.

[0051]

As described above, according to the present invention,
An image sensor, first to n-th (n is a positive integer of 2 or more) image data storage means for storing image data obtained by the image sensor, and an image obtained by the image sensor. Adding means for adding data and image data stored in each of the image data storage means, wherein when the exposure of the image sensor is updated every predetermined period, the image sensor is exposed by a first period of exposure. Is stored in the first image data storage means, and the image data obtained from the image sensor by the exposure during the second period and the image data stored in the first image data storage means Are stored in the second image data storage means. Similarly, the image data obtained by the image sensor by the exposure in the n-th period and the (n-1) th image data storage are similarly stored. Stored in the means The image data obtained by the exposure in the first to (n-1) th periods are added with the added image data and stored in the n-th image data storage means. Since the image data stored in the n image data storage means can be arbitrarily read, it is possible to selectively obtain the image data integrated (added) up to that time and the image data integrated up to one period before. There is an effect that the image data can be returned to the image data one period before as soon as it is felt that the image is overexposed, and the image can be processed.

Also, an image sensor, first image data storage means for storing image data obtained by the image sensor, and an image data storage device for storing image data obtained by the image sensor. A second image data storage unit, and image data obtained by the image sensor and image data stored in the first image data storage unit or the second image data.
Adding means for adding the image data stored in the first image data storing means, the writing timing of the image data to the first image data storing means and the second image data storing means, and the first image data Control means for controlling timing of reading image data from the storage means and the second image data storage means; and selecting image data stored in the first image data storage means or the second image data storage means. And an image display means for displaying based on the selected image data, wherein the exposure of the image sensor is performed for a predetermined one reference period. When updated every time, the image data obtained from the image sensor in the first reference period after the start of exposure is stored in the first image data storage means. Adding the image data obtained from the image sensor in the next one reference period and the image data stored in the first image data storage means and storing the result in the second image data storage means; The image data obtained from the image sensor in the next one reference period and the image data stored in the second image data storage are sequentially added and stored in the first image data storage. As a result, the same effect as described above can be obtained, and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment.

FIG. 2 is a timing chart illustrating a storage operation according to an embodiment;

FIG. 3 is a flowchart illustrating a storage control operation according to an embodiment;

FIG. 4 is a block diagram showing a configuration of a conventional example.

FIG. 5 is a timing chart showing an operation of a conventional example.

[Explanation of symbols]

Reference Signs List 101 solid-state imaging device 102 imaging device control circuit 103 timing generator 104 reference oscillator 105 camera signal processing circuit 106 A / D converter 107 adder (addition means) 108 memory (first image data storage means) 109 memory (second image) Data storage means) 110 Memory controller (Image data storage control means) 111 Trigger switch (Control switch) 112 Image selection controller (Image selection means) 113 Switching circuit 114 Switching circuit 115 D / A converter 116 Recording signal processing circuit 117 Storage ( Recording medium) 118 Monitor signal processing circuit 119 LCD (image display means)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4M118 AA10 AB01 BA13 FA06 GA10 5C022 AA02 AB17 AB20 AB52 AC01 AC32 AC42 AC52 AC54 AC69 CA02 5C024 AA01 CA03 CA12 DA04 DA07 FA11 GA11 GA49 GA50 HA14 HA17 HA21 HA24 HA27 JA21

Claims (5)

[Claims] 1. An image pickup device and first to n-th (n is 2) for storing image data obtained by the image pickup device.
(Positive integer as described above) image data storage means, and addition means for adding the image data obtained by the image sensor and the image data stored in each of the image data storage means. When the exposure is updated every predetermined period, the image data obtained from the imaging device by the exposure during the first period is stored in the first image data storage unit,
The image data obtained from the image sensor by the exposure during the second period is added to the image data stored in the first image data storage unit, and the added image data is stored in the second image data storage unit. The image data obtained by the image sensor by the exposure in the n-th period and the (n-
1) to (n) stored in the image data storage means of (1).
The image data obtained by the exposure up to -1) is added to the added image data and stored in the n-th image data storage means, and the first to n-th image data storage means are added. An image pickup apparatus characterized in that image data stored in the image data can be arbitrarily read. 2. An image pickup device, first image data storage means for storing image data obtained by the image pickup device, and an image data storage device for storing image data obtained by the image pickup device. Second image data storage means, and image data obtained by the image sensor and image data stored in the first image data storage means or image data stored in the second image data storage means. Adding means for adding, timing for writing image data to the first image data storage means and the second image data storage means, and a timing for writing the image data from the first image data storage means and the second image data storage means. Control means for controlling image data readout timing; and image data stored in the first image data storage means or the second image data storage means. An image selection means for selecting, a recording medium for recording the selected image data, and an image display means for displaying based on the selected image data, wherein the exposure of the image sensor is determined by a predetermined standard. When updated every period, image data obtained from the image sensor in the first one reference period after the start of exposure is stored in the first image data storage means, and the image sensor is stored in the next one reference period. Is added to the image data stored in the first image data storage means and stored in the second image data storage means.
Controlling to add the image data obtained from the image sensor in the reference period and the image data stored in the second image data storage unit and store the added image data in the first image data storage unit. An imaging device characterized by the above-mentioned. 3. The image pickup apparatus according to claim 2, further comprising a control switch for recording image data on a recording medium at a desired timing. 4. A first to n-th (n is a positive integer of 2 or more) image data storage means for storing image data obtained by an image sensor, and an image obtained by the image sensor. Adding means for adding data and the image data stored in each of the image data storing means is provided, and when the exposure of the image sensor is updated every predetermined period, the first
The image data obtained from the image sensor by the exposure during the period is stored in the first image data storage means, and the image data obtained from the image sensor by the exposure during the second period and the first image data are stored. Adding the image data stored in the storage means and storing the result in the second image data storage means;
Similarly, the image data obtained by the image sensor by the exposure in the n-th period sequentially and the first to (n-1) -th periods stored in the (n-1) -th image data storage means. Wherein the image data obtained by the exposure is added to the added image data and stored in the n-th image data storage means. 5. An image pickup device, first image data storage means for storing image data obtained by the image pickup device, and a storage device for storing image data obtained by the image pickup device. Second image data storage means, and image data obtained by the image sensor and image data stored in the first image data storage means or image data stored in the second image data storage means. Adding means for adding, timing for writing image data to the first image data storage means and the second image data storage means, and a timing for writing the image data from the first image data storage means and the second image data storage means. Control means for controlling image data readout timing; and image data stored in the first image data storage means or the second image data storage means. Image selection means for selecting, a recording medium for recording the selected image data, and image display means for displaying based on the selected image data are provided, and the exposure of the image sensor is set to a predetermined value. When updated every reference period, image data obtained from the image sensor in the first one reference period after the start of exposure is stored in the first image data storage means, and the image data is stored in the next one reference period. The image data obtained from the element and the image data stored in the first image data storage unit are added and stored in the second image data storage unit. And controlling the image data obtained from the image sensor and the image data stored in the second image data storage means to be added and stored in the first image data storage means. To be Control method for an image device.