JP2002084453A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device that can reduce a photographing time and a photographing interval in a multiplex image photographing mode without causing a large scale or a cost increase and decrease the effect of camera-shake or the like to acquire proper images. SOLUTION: The image pickup device is provided with a signal amplifier means 37 that amplifies an image signal obtained by an imaging device 12 at a setting value of the sensitivity equivalent to ISO sensitivity and a sensitivity revision control means 30 applies revision control to the sensitivity setting value equivalent to the ISO sensitivity in response to the photographing mode. Thus, setting the sensitivity setting value in the multiplex image photographing mode higher than the sensitivity setting value in the usual photographing mode can use a high shutter speed, decrease the photographing time and the photographing interval, receive less effect even on the occurrence of a motion in an object or of a camera-shake and acquire images having no problem on synthesis processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an imaging apparatus such as a digital camera having a multiple image shooting mode in addition to a normal shooting mode.

[0002]

2. Description of the Related Art In order to perform multiple image processing for obtaining one composite image from a plurality of captured images, there is known a digital camera capable of capturing a plurality of images in a multiple image capturing mode. Acquisition of the plurality of images in such a multiple image shooting mode is based on the assumption that the same subject is shot at substantially the same shooting position. Therefore, in the multiple image shooting mode, the same subject is continuously shot. Will be.

However, in actual photographing, the subject may move delicately or shake with time, and it is difficult to obtain a plurality of image data which are all suitable for the synthesis processing.

In the multiple image photographing mode, in order to reduce the influence of such camera shake, it is preferable to shorten the photographing time and the photographing interval per time as much as possible.

For this reason, conventionally, a method of simultaneously obtaining a plurality of image data using a plurality of image sensors, and a high-speed system clock in order to shorten the time for reading an image signal from an image pickup device such as a CCD. A method has been devised.

[0006]

However, in the former case, since a plurality of images can be obtained at the same time, it is possible to suppress the influence of the movement of the subject and the effect of camera shake due to the passage of time. , The outer shape becomes large and the production cost rises.
Also, in the latter case, since a high-speed system clock is used, there is a problem that the configuration becomes expensive and is difficult to implement.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and can reduce the photographing time and the photographing interval without increasing the size and the cost, avoiding the effects of camera shake and the like, and performing multiple image processing. It is an object of the present invention to provide an imaging device capable of obtaining a plurality of images suitable for a computer.

[0008]

An object of the present invention is to provide an image pickup device, a mode selection device capable of setting a multiple image photographing mode in addition to a normal photographing mode, and an image signal obtained by the image pickup device, which can be used for ISO sensitivity. It is possible to solve the above problem by an imaging apparatus, comprising: signal amplifying means for amplifying with a corresponding sensitivity setting value; and sensitivity changing control means for changing the sensitivity setting value according to the shooting mode.

In this imaging apparatus, the image signal obtained by the imaging means is amplified by the signal amplifying means at a sensitivity setting value corresponding to the ISO sensitivity. At this time, the sensitivity switching control unit changes the sensitivity setting value according to whether the shooting mode is the normal shooting mode or the multiple image shooting mode.

That is, in the multiple image photographing mode, if the sensitivity setting value corresponding to the ISO sensitivity is set higher than the sensitivity setting value in the normal photographing mode, the exposure time per photographing and photographing at a high shutter speed are increased. The interval is reduced. As a result, it becomes possible to cope with a moving subject, the effects of camera shake and the like are reduced, and it becomes possible to acquire a plurality of appropriate images.

[0011]

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

FIG. 1 is an external perspective view of a digital camera as an imaging apparatus according to an embodiment of the present invention, and FIG. 2 is a rear view of the digital camera.

1 and 2, a digital camera 1 is provided with a photographic lens 11 on the front surface of a camera body 1A, and a finder window 14 and a distance measuring window 19 on the upper front surface. And the camera body 1
A is an image pickup device, which is an image pickup device serving as an image pickup unit that receives an optical image from the photographing lens 11 and performs photoelectric conversion.
D12 is provided.

Further, a release (shutter) button 13 and a photographing condition setting key 17 are provided on the upper surface of the camera body 1A.
And a liquid crystal panel 18 and the like. An insertion port 16 is provided on the side surface of the camera body 1A so that the recording medium 15 can be inserted and removed.

With the photographing condition setting key 17, the liquid crystal panel 1
While viewing the display contents of 8, the user can set exposure conditions such as aperture priority and shutter speed priority, switch macro shooting, and further set zoom.

As shown in FIG. 2, a liquid crystal monitor 111 for live view display and an image processing mode setting key 110 are provided on the back of the camera body 1A. With the image processing mode setting key 110, a normal shooting mode and a multiple image shooting mode can be selected and set.

This digital camera 1 is capable of recording an image captured by the CCD 12 on a recording medium 15 in the same manner as a normal camera.

The multiple image shooting is a function of obtaining a single image by continuously shooting a plurality of images of the same subject and performing a predetermined synthesizing process on the obtained plurality of image data. Has the following four shooting modes.

(1) High-resolution imaging This is a so-called image shifting method disclosed in Japanese Patent No. 2635917, in which a subject is imaged every time the position of an image sensor is minutely displaced, and a plurality of image data obtained are used. Obtain higher and higher resolution images.

(2) Blur control Patent No. 2883648, Kubota, Aizawa: "Registration in consideration of rotation of multifocal image and high-speed reconstruction by inverse filter method of arbitrary focal image", IE99-IEICE-
25 (1999-07) and the like,
A plurality of images are taken while changing the focus position, and an omnifocal image or an image in which the background blur is enhanced is obtained using the obtained plurality of images.

(3) Shake-off shooting When shooting at a shutter speed Ts at which there is a possibility of camera shake, n images are taken at a shutter speed of Ts / n (select n so that camera shake does not occur), and the images are taken. Is added to obtain an image without camera shake.

(4) Noise Reduction Photographing Noise can be reduced by photographing a plurality of times under the same exposure conditions and averaging a plurality of obtained images.

In this embodiment, as the multiple image shooting,
Although high-resolution shooting by the shift shooting method is performed,
It is needless to say that the present invention can be applied to other multiple image capturing.

FIG. 3 is a block diagram showing the electrical configuration of the digital camera 1, wherein thin arrows indicate the flow of control data, and thick arrows indicate the flow of image data.

In FIG. 3, the CCD 12 is set so as to be slightly displaceable in the optical axis direction, and is driven to be displaced by the CCD position control unit 34 at the time of the second photographing in the shift photographing mode. The CCD position control unit 34 is composed of, for example, a piezoelectric element.

The analog signal amplifier 37 amplifies the analog image signal from the CCD 12, and the analog gain set value switching unit 38 switches the shift shooting mode ON (multiple shooting mode) or OFF (normal shooting mode). A set value (also referred to as a gain) of a sensitivity corresponding to the ISO sensitivity is set in the analog signal amplifier 37 according to the setting.

The A / D converter 31 converts an analog image signal from the CCD 12 into digital image data, and the RAM 32 temporarily stores the image data. The image synthesizing unit 33 is OFF (no processing) in the normal shooting mode.
In the shift shooting mode, a single image is created by combining a plurality of images. The recording medium 15 stores the image data read from the RAM 32 in the normal shooting mode, and stores the image data combined by the image combining unit 33 in the shifted shooting mode.

The CPU 30 controls each section, and controls the entire digital camera 1 as a whole. For example, in addition to storing shooting conditions when the release button 13 is pressed, the setting state of the image processing mode setting key 110, and the like, the shooting lens driving unit 36 is controlled based on the distance measurement result in the distance measurement window 19. It controls and drives the taking lens 11.

Reference numeral 310 denotes a photometric unit. The CPU 30 calculates the integration time of the CCD 12 based on data from the photometric unit 310 and the like, as will be described later.
The CCD 12 is integrated (exposed) via 9.

In this embodiment, as shown in FIG. 4, in the image processing mode, the OF of the shift photographing mode is performed.
At F, a sensitivity setting value corresponding to ISO sensitivity 200 is set, and when the shift shooting mode is ON, ISO sensitivity 8
A sensitivity setting value corresponding to 00 is set.

The CPU 30 calculates the integration time according to the set sensitivity setting value, and integrates the CCD 12 via the integration time control unit 39.

Next, the photographing sequence by the digital camera 1 having the above configuration will be described with reference to the flowcharts of FIGS. In the following description and drawings,
Steps are abbreviated as “S”.

Before photographing, the user sets the photographing condition setting key 1
The setting of exposure conditions such as aperture priority and shutter speed priority and switching of white balance mode are performed by the LCD panel 7 and the liquid crystal panel 18.

In S101, it is determined whether or not the release button 13 has been pressed, and when the release button 13 has been pressed (S101).
In step S102, the CPU 30 reads the current photographing conditions and image processing mode settings. If the release button 13 is not pressed (NO in S101), the process waits until the release button 13 is pressed. Thereafter, distance measurement is performed in S103.

In S104, the image processing mode is
It is determined whether or not the shift shooting mode is OFF. If the shift shooting mode is set to OFF (the determination in S104 is Y
ES), since the mode is the normal shooting mode, in S105, the CP
U30 instructs the analog gain setting switching unit 38 to adopt the set value for normal shooting, and performs normal shooting.

That is, in step S106, the photographic lens 11 is driven via the photographic lens driving unit 36 so as to focus on the subject.
From the data obtained in step 10, an operation is performed based on the set sensitivity setting value to calculate an integration time. And S108
Then, the CPU 30 integrates (exposes) the CCD 12 with the calculated integration time via the integration time control unit 39, and reads out an image signal as data in S109.

In S110, the read image signal is
The signal is amplified by the analog signal amplifier 37 with a sensitivity setting value corresponding to the ISO sensitivity 200, that is, a set gain. S
At 111, the amplified image signal is output from the A / D converter 3
In step S112, the digital image data is temporarily stored in the RAM 32. Then, in S113, the CPU 30 sets the image combining unit 33 to OF
F (no processing) is set, and in S114, the image data is read from the RAM 32 and recorded on the medium 15.

On the other hand, if the shift photographing mode ON is set in S104 (the judgment in S104 is N
O), shift shooting is started, and the process proceeds to S201 in FIG.

In FIG. 6, in S201, the CPU 30
Designates the analog gain setting switching unit 38 to adopt the set value for the shift shooting, and the shooting is performed.

That is, in S202, the photographic lens 11 is driven via the photographic lens driving unit 36 so as to focus on the subject. In S203, the CPU 30 sets the data based on the data obtained by the photometric unit 310. The integration time is calculated based on the sensitivity setting value obtained. In S204,
The CPU 30 integrates the CCD 12 with the calculated integration time via the integration time control unit 39, and reads out the image signal as the first image data in S205.

In step S206, the read image signal is amplified by the analog signal amplifier 37 with a sensitivity setting value corresponding to the ISO sensitivity 800, that is, a setting gain larger than the setting gain in the normal photographing mode. In S207, the amplified image signal is converted into digital image data by the A / D converter 31, and in S208, the digital image data is temporarily stored in the RAM 32.

Next, in S209, the CPU 30
The position of the CCD 12 is displaced via the CD position control unit 34, and it is determined whether the CCD 12 has been displaced by a predetermined amount. If the position of the CCD 12 is displaced by a predetermined amount (the determination in S209 is YES), Returning to S202, the second shooting is performed as described above. If the position of the CCD 12 is not displaced by a predetermined amount (NO in S209),
Stand by at 209.

Thereafter, in S210, the CPU 30 determines whether or not a plurality of (two) images have been taken, and if a plurality of (two) images have been taken (the determination in S210 is YES), S211.
After reading these two pieces of image data from the RAM 32, the image combining unit 33 performs a predetermined image combining process on the two pieces of image data to combine one image in S212. Record at 15.

Next, regarding the photographing time for each photographing mode,
This will be described with reference to FIG.

FIG. 7A shows the time required for photographing in the case of normal photographing at a sensitivity setting value equivalent to ISO sensitivity 200,
FIG. 7B shows a time required for photographing when multiple images are photographed (shifted photographing) while keeping a sensitivity setting value equivalent to ISO sensitivity 200, and FIG. 7C shows a sensitivity setting corresponding to ISO sensitivity 800. The value indicates the time required for shooting when multiple images are shot.

The digital camera 1 here has a CCD 12
For example, it is assumed that a device having 3 million pixels is mounted and the system clock is driven at 60 MHz. Therefore, it takes 0.05 sec to read one screen. In the normal shooting mode, shooting is performed with a sensitivity setting value equivalent to ISO sensitivity 200, and in the case of shooting multiple images, shooting is performed twice.

In this digital camera, it is assumed that the proper shutter speed when photographing a subject in the normal photographing mode is 0.1 sec as shown in FIG.

If multiple image shooting is performed without changing the sensitivity setting value corresponding to the ISO sensitivity 200, the time until the multiple image shooting ends is 0.2 as shown in FIG. 7B.
It takes 5 seconds. In this case, it is difficult to cope with a moving subject, and the influence of camera shake is large, so that it is difficult to obtain an appropriate image for the synthesis processing.

On the other hand, as shown in FIG.
If the sensitivity setting value corresponding to the ISO sensitivity 800 has been changed at the time of multiplex image shooting, the appropriate shutter speed becomes １ ／ of that of normal shooting. That is, one exposure period is 0.025 sec. As a result, the time until the end of the multiple image shooting may be the same as the time required for the normal shooting (0.1 sec).

As described above, when shooting multiple images, the ISO
By setting the sensitivity setting value corresponding to the sensitivity higher than the sensitivity setting value at the time of normal photographing, a fast shutter speed can be used for a fixed integral value, and the photographing time and the photographing interval can be shortened. For this reason, even if the subject moves or shakes, it is possible to acquire a plurality of image data having no problem in response to the movement and synthesize the desired image.

Further, as compared with a device using a large number of image pickup devices, the device can be made smaller and more compact, and can be manufactured at a lower cost than a device using a high-speed system clock.

In the above-described embodiment, the shift photographing method has been described as the method of photographing multiple images. However, another method may be used.

Further, in the above embodiment, the signal amplification processing corresponding to the ISO sensitivity is performed by the analog signal amplifier 37. However, the present invention is not limited to this, and the A / D converter 31 performs the A / D conversion.
By providing a digital signal amplifier for the converted image data, signal processing corresponding to ISO sensitivity may be performed. Further, a gamma correction unit may be provided.

Further, the digital camera 1 is provided with an image synthesizing means 33 for synthesizing one image from a plurality of images shot in the multiple image shooting mode. Although the processing up to the generation of the image is performed by a single imaging apparatus, the digital camera may perform only shooting without providing an image synthesis unit, and the image synthesis may be performed by an image processing apparatus such as a personal computer.

[0055]

According to the present invention, the sensitivity setting value corresponding to the ISO sensitivity is changed according to the photographing mode. Therefore, the sensitivity setting value in the multiple image photographing mode is changed to the sensitivity setting value in the normal photographing mode. Setting a higher value can use a faster shutter speed and shorten the shooting time and shooting interval. As a result, even if the subject moves or shakes, it is possible to acquire multiple images that have no problem in the synthesis process while minimizing the effects of these and minimize the size and cost. It will be easier.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a digital camera according to an embodiment of the present invention.

FIG. 2 is a rear view showing the same digital camera.

FIG. 3 is a block diagram showing an electrical configuration of the digital camera.

FIG. 4 is also a shift shooting mode O of the digital camera.
It is a table | surface which shows the example of the setting content corresponding to FF and ON.

FIG. 5 is a flowchart showing a shooting sequence of the digital camera.

FIG. 6 is a flowchart illustrating processing in a shift shooting mode.

FIG. 7 is an explanatory diagram of a photographing time for each photographing mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Digital camera 12 ... CCD (imaging means) 30 ... CPU (Sensitivity change control means) 37 ... Analog signal amplifying part (signal amplifying means) 110 ... Image processing mode setting key (mode) Selection means)

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Claims (1)

[Claims] 1. An image pickup unit, a mode selection unit capable of setting a multiple image pickup mode in addition to a normal image pickup mode, and an image signal obtained by the image pickup unit is amplified by a sensitivity set value corresponding to an ISO sensitivity. An image pickup apparatus, comprising: a signal amplifying unit that performs a setting operation; and a sensitivity change control unit that changes a set value of the sensitivity in accordance with the shooting mode.