JP2002190978A - Electronic camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic camera in which consecutive shots can be taken at high speed. SOLUTION: The electronic camera comprises an photographing lens section 11, means 14 for splitting the light beam from an object passed through the photographing lens section into a plurality of light beams, a plurality of image sensors 15a-15c disposed to receive the plurality of light beams of the object from the light beam splitting means, imaging means 16a-16c causing the image sensors to perform exposing operation and outputting an image signal converted photoelectrically by the image sensor as image data, and means 18 for controlling the imaging means to perform consecutive photographings by shifting the exposure operation timing of the plurality of image sensors sequentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic camera, and more particularly to continuous shooting and bracket shooting in an electronic camera.

[0002]

2. Description of the Related Art Unlike a silver halide camera, an electronic camera is not limited by a film winding speed or the like, and therefore can perform high-speed continuous shooting (continuous shooting). However, when the number of pixels increases, the readout time (charge transfer time) from the image sensor also increases in proportion to the increase, making it difficult to perform continuous shooting at high speed.

[0003] In addition, the above-mentioned problem of high speed may be a problem in bracket photographing. Bracketing is to perform multiple shootings with different exposure conditions.However, conventionally, each shooting must be performed at different shooting timings. In this case, an image taken with the optimal exposure may deviate from a desired composition.

[0004]

As described above, in the conventional electronic camera, when the number of pixels is large and the reading time from the image pickup element is long, it is difficult to perform high-speed continuous shooting or bracket shooting. was there.

An object of the present invention is to provide an electronic camera capable of performing continuous shooting or bracket shooting at high speed.

[0006]

According to the present invention, there is provided an electronic camera comprising: a photographing lens unit; a light beam dividing unit for dividing a subject light beam passing through the photographing lens unit into a plurality of light beams; A plurality of image sensors provided to receive the subject light flux; an imager configured to cause the image sensor to perform an exposure operation, and output an image signal photoelectrically converted by the image sensor as image data; And a photographing control means for controlling the image pickup means so as to perform continuous photographing by sequentially shifting the timing of the exposure operation of the image pickup device.

In the above invention, the light beam splitting means includes:
It is a prism unit that divides an incident light beam into three beams and emits the light beams, and the image pickup device is preferably provided on each of three emission surfaces of the prism unit.

In the above invention, the light beam splitting means includes:
A prism unit that divides the incident light beam into three light beams and emits the divided light beams. The plurality of image sensors are provided on two emission surfaces of the prism unit, and a detection element for performing focus detection is provided on another one emission surface. Preferably, it is provided.

In the above invention, the light beam splitting means includes:
A prism unit that divides the incident light beam into three light beams and emits the divided light beams. The plurality of image pickup devices are provided on two emission surfaces of the prism unit, and a moving image pickup device having a smaller number of pixels than the image pickup device is used. Preferably, it is provided on one emission surface.

Further, the electronic camera according to the present invention has a photographing lens section, a light beam dividing means for dividing a subject light beam passing through the photographing lens section into a plurality of light beams, and a plurality of subject light beams from the light beam dividing means. A plurality of imaging elements provided to receive light, an imaging unit for causing the imaging element to perform an exposure operation, and outputting an image signal photoelectrically converted by the imaging element as image data; and A photographing control means for controlling the image pickup means so that photographing is performed simultaneously with different exposure conditions.

In the above invention, the light beam splitting means includes:
It is a prism unit that divides an incident light beam into three beams and emits the light beams, and the image pickup device is preferably provided on each of three emission surfaces of the prism unit.

According to another aspect of the present invention, there is provided an electronic camera, comprising: a photographing lens unit; a light beam dividing unit for dividing a subject light beam passing through the photographing lens unit into a plurality of light beams; and a plurality of subject light beams from the light beam dividing unit. A plurality of imaging elements provided to receive light; aperture means for changing the diameter of the aperture to limit the amount of light incident on the imaging element; and causing the imaging element to perform an exposure operation and performing photoelectric conversion by the imaging element. And an imaging unit for outputting the obtained image signal as image data, and controlling the imaging unit so as to sequentially change the aperture diameter of the aperture unit and sequentially shift the timing of the exposure operation of the plurality of imaging elements to perform imaging. Shooting control means.

[0013]

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

(Embodiment 1) The present embodiment relates to an electronic camera having a continuous shooting (continuous shooting) function. Hereinafter, a configuration example of the electronic camera according to the present embodiment will be described with reference to the blocks illustrated in FIG.

In the electronic camera according to the present embodiment, the subject light passing through the photographing lens unit 11 is split into a light beam through an aperture 12 controlled by an aperture control unit 13 (including a step motor and a motor control unit). The light is incident on a prism section 14 constituting the means, and the prism section 14 divides a subject light beam into a plurality of light beams. Image sensors 15a, 15b, and 15c are arranged near the emission surfaces 14a, 14b, and 14c of the prism section 14, respectively. These image sensors 15a, 15b and 15
For c, a photoelectric conversion element such as a CCD is used.

The imaging devices 15a, 15b and 15c have imaging units (imaging circuit units) 16a, 16b and 16 respectively.
c is connected, and various processes such as CDS, AGC, and A / D conversion are performed. Imaging units 16a, 16b and 16c
Is connected to the SRAM 17, and the imaging unit 16
a, 16b and 16c are stored in the SRAM 17
Is temporarily held.

Each part of the electronic camera is connected to a bus 19. Each part of the electronic camera is controlled by a main CPU 18, and a control program is stored in a flash memory 20. The bus 19 has a sub CPU.
The sub CPU 21 performs input control of an operation unit 22 (including various instruction switches such as a release button and a cross button), timer management, and the like.

The SDRAM 23 has a function as a buffer memory, and temporarily stores image data obtained by the image pickup unit, and is also used as a work area for various processes such as image processing. The signal processor unit 24 performs various processes such as a γ conversion process, a color conversion process, an AE process, an AF process, and an AWB process.
The G unit 25 performs JPEG compression / decompression processing on image data. The recording unit 26 is for recording image data or the like that has been JPEG-compressed on a recording medium such as a memory card. The LCD display unit 27 displays various information in addition to the image obtained by the imaging unit, and is driven by the LCD drive unit 28.

Next, the operation of continuous shooting (continuous shooting) using the electronic camera shown in FIG. 1 will be described with reference to the timing chart shown in FIG.

After the continuous shooting mode is set by the operation unit 22, the continuous shooting is started by operating the release button of the operation unit 22, but as shown in FIG.
Continuous shooting is performed by sequentially shifting the exposure timings of a, 15b, and 15c.

That is, first, an exposure process (image pickup process) and a readout process (image pickup device 15a) are performed in the image pickup device 15a.
In addition to the reading process of the image signal from the image capturing unit 16a to the image capturing unit 16a, the CDS, AGC and A / D conversion process in the image capturing unit 16a, and the process of storing the image data from the image capturing unit 16a to the SDRAM 23 are also performed. Thereafter, image processing such as γ conversion processing and color conversion processing is performed. In the image pickup device 15b, the exposure process is started while the readout process is being performed by the image pickup device 15a.
In 5c, the exposure process is started while the readout process is being performed in the image sensor 15b. Further, the image sensor 15a
The second exposure process is started while the readout process is being performed by the image sensor 15c. Thereafter, similarly, the exposure process and the readout process are sequentially performed in each image sensor, and each image process is performed after each readout process.

When the continuous shooting is completed in this way, the SDR
Each image data stored in the AM 23 is subjected to a compression process by the JPEG unit 25, and the compressed image data is recorded by the recording unit 26 on a recording medium such as a memory card. Note that the image processing need not be performed each time after each reading processing, and may be performed collectively after the continuous shooting is completed and before the JPEG compression processing is performed.

As described above, in the present embodiment, the image pickup elements 15a, 14b,
15b and 15c are provided, and an exposure process of another image sensor (for example, the image sensors 15b and 15c) is performed during a read process of a certain image sensor (for example, the image sensor 15a). The time interval between each exposure process can be greatly reduced as compared with the case where the next exposure process is performed after the process is completed. Therefore, even if the number of pixels of the image sensor increases and the readout time from the image sensor increases, continuous shooting can be performed at high speed. Also, by using a prism as the light beam splitting means, it is possible to make the optical system compact.

Next, a modification of this embodiment will be described.

FIG. 3 is a block diagram showing a first modification. The basic configuration is the same as the configuration shown in FIG. 1, and the same reference numerals are given to the components corresponding to the components shown in FIG.

In this modification, the image pickup devices 15a and 15b are used for photographing still images, and the image pickup device 15c is used for photographing moving images. As the moving image pickup device 15c, one having a smaller number of pixels than the still image pickup devices 15a and 15b is used. The imaging devices 15a and 15b for still images are connected to imaging units 16a and 16b, respectively, and an SRAM 17a is connected to the imaging units 16a and 16b. The moving image pickup device 15c is connected to the image pickup unit 16c,
The SRAM 17b is connected to 6c.

The basic operation in continuous shooting is shown in FIGS.
In the same manner as in the example shown in FIG. 1, during the reading process of a certain image sensor (for example, the image sensor 15a), the exposure process of another image sensor (for example, the image sensor 15b) is performed. The same effect as the example shown in FIG. 2 can be obtained.

FIG. 4 is a block diagram showing a second modification. The basic configuration is the same as the configuration shown in FIG. 1, and the same reference numerals are given to the components corresponding to the components shown in FIG.

In this modification, an AF phase detecting element 31 is provided on the exit surface 14c of the prism instead of the image pickup element 15c. The phase detection element 31 performs focus detection by a phase difference detection method, and includes a light detection element 31a (1
Dimensional photocell) and a pair of separator lenses 31b. That is, the subject light emitted from the emission surface 14c is formed as a pair of images on the light detection element 31a by the pair of separator lenses 31b. When the image interval on the photodetector 31a when the focus is at the position of the reference imaging plane P (that is, when the taking lens is in focus on the subject) is the reference interval L, When the image is focused on the near side of the imaging plane P (on the exit surface 14c side), the image interval on the photodetector 31a is narrower than the reference interval L, and conversely behind the reference imaging plane P. Side (photodetection element 31a
Side), the light detection element 31a is in focus.
The above image interval is wider than the reference interval L. Since a signal corresponding to the image interval is output from the light detection element 31a, the defocus amount can be obtained from the output signal.

The output of the light detecting element 31a is input to the defocus amount calculation unit 33 via the amplifier 32, and the defocus amount calculation unit 33 calculates the defocus amount. The calculation result of the defocus amount is the main CPU 1
8, a drive control signal corresponding to the defocus amount is sent from the main CPU 18 to a lens driving unit (not shown), and the lens unit is controlled so that the image interval on the photodetector 31 a becomes the reference interval L. The position of the focusing lens at 11 is adjusted.

The basic operation in continuous shooting is shown in FIGS.
In the same manner as in the example shown in FIG. 1, an exposure process for another image sensor (for example, the image sensor 15b) is performed during a read process for a certain image sensor (for example, the image sensor 15a). The same effect as the example shown in FIG. 2 can be obtained.

FIG. 5 is a diagram showing a third modification.
In the example shown in FIG. 1 and the like, the exit surface of the prism section 14 has a three-sided configuration (three-plate type). In the example shown in FIG. 5, the exit side of the prism portion 14 has a two-sided configuration (two-plate type). Imaging elements 15a and 15b are provided on the emission surfaces 14d and 14e, respectively.
Has been arranged. Other basic configurations are the same as those in the example shown in FIG. 1 and the like, and basic operations and basic effects in continuous shooting are the same as those in the examples already shown.

FIG. 6 is a diagram showing a fourth modification.
In the example shown in FIG. 1 and the like, a prism is used as the light beam splitting means, but in this example, the light beam splitting means is constituted by the half mirrors 41a and 41b. That is, the image sensors 15a, 15b are provided by the half mirrors 41a and 41b.
And 15c, the subject light is evenly distributed, for example. Figure 1 shows other basic configurations
And the like, and the basic operation and basic effects in continuous shooting are the same as the examples already shown.

FIG. 7 is a diagram showing a fifth modification.
In this example, the prism 14 and the half mirror 41 constitute a light beam splitting unit.
For example, the subject light is evenly distributed to a, 15b, and 15c. The other basic configuration is the same as the example shown in FIG. 1 and the like, and the basic operation and basic operation and effect in continuous shooting are the same as the example already shown.

(Embodiment 2) Next, a second embodiment of the present invention will be described. The present embodiment relates to an electronic camera having a bracket photographing function of performing photographing a plurality of times with different exposure conditions. Note that the basic configuration of the electronic camera is the same as that of the first embodiment, and it is possible to adopt various configurations shown in the first embodiment. In the following description, unless otherwise specified, the configuration shown in the block diagram of FIG. 1 is used.

The operation of the bracket photographing using the electronic camera shown in FIG. 1 will be described with reference to the timing chart shown in FIG. In this example, as shown in FIG.
It is assumed that the bracketing shooting is performed by setting the exposure condition to five levels from -1 EV to +1 EV.

The bracket photographing is started by operating the release button of the operation unit 22 after setting the bracket photography mode by the operation unit 22.

First, the image pickup devices 15a, 15b and 15c
, Exposure processing (imaging processing) and readout processing (imaging elements 16a, 15b, and 15c
In addition to the readout processing of the image signals to the 6b and 16c, the CDS, AGC and A / D conversion processing in the imaging units 16a, 16b and 16c, and the storage processing of the image data from the imaging units 16a, 16b and 16c to the SDRAM 23 are also included.
Are performed substantially simultaneously in parallel. At this time, the exposure time of each of the imaging devices 15a, 15b and 15c (element shutter speed, t2 = 1.4 × t1, t3 = 0.7 × t
1, t4 = 2.0 × t1, t5 = 0.5 × t1) to change the exposure conditions (0 EV, +0.5 EV, −0.5
EV).

When the reading process is completed, the image pickup devices 15a and 15b perform the second exposure process and the reading process in the same manner as the above-described operation. Also at this time, the exposure conditions (+1 EV, -1 EV) are changed by changing the exposure time of the imaging elements 15a and 15b.

When the bracket photography is completed in this manner, image processing such as γ conversion processing and color conversion processing is performed on each image data stored in the SDRAM 23. Furthermore, JPEG is applied to each image data subjected to image processing.
The compression processing is performed by the unit 25, and the compressed image data is recorded by the recording unit 26 on a recording medium such as a memory card.

As described above, in the present embodiment, the image pickup elements 15a, 14b,
15b and 15c are provided so that the exposure process and the readout process are performed in parallel by each image pickup device. Therefore, unlike the conventional case where the exposure process and the readout process are repeatedly performed by a single image pickup device, Simultaneity and high speed can be ensured. Therefore, even if the number of pixels of the image sensor increases and the readout time from the image sensor increases, bracket shooting can be performed at high speed.
Even in the case where the subject moves, it is possible to obtain an image of the optimal composition photographed with the optimal exposure. Also, by using a prism as the light beam splitting means, it is possible to make the optical system compact.

(Embodiment 3) Next, a third embodiment of the present invention will be described. As in the second embodiment, the present embodiment also relates to an electronic camera having a bracket photographing function. The basic configuration of an electronic camera is
This is the same as the first embodiment, and it is possible to adopt various configurations shown in the first embodiment. In the following description,
Unless otherwise specified, the configuration shown in the block diagram of FIG. 1 is used.

The operation of bracket photographing in this embodiment will be described with reference to the timing chart shown in FIG. Also in this example, as in the second embodiment, it is assumed that bracket exposure is performed with exposure conditions set to five levels from -1 EV to +1 EV.

The bracket photographing is started by operating the release button of the operation unit 22 after setting the bracket photography mode by the operation unit 22. In the second embodiment shown in FIG. 8, each of the imaging elements 15a, 15b, and 15
Although the exposure condition is varied by changing the exposure time (element shutter speed) of c, in the present embodiment,
As shown in FIG. 9, the exposure condition is varied by keeping the element shutter speed constant (for example, 1/125 second) and changing the aperture diameter of the aperture 12 (setting the F number from F4 to F8). . Further, since a single stop 12 is used, the exposure timings of the imaging elements 15a, 15b and 15c are sequentially shifted.

First, the F number is set to F5.6,
In addition to the exposure process (imaging process) and the reading process (the process of reading the image signal from the imaging device 15a to the imaging unit 16a), the CDS in the imaging unit 16a,
AGC and A / D conversion processing, SDRA from imaging unit 16a
M23 (including a process of storing image data in M23).
When the exposure processing in the image sensor 15a ends, the F number is changed to F4.5, and the exposure processing in the image sensor 15b is started while the read processing is being performed in the image sensor 15a. Thereafter, similarly, the exposure process and the readout process are sequentially performed in each image sensor while sequentially changing the F-number.

When the bracket shooting is completed in this way, image processing such as γ conversion processing and color conversion processing is performed on each image data stored in the SDRAM 23. Furthermore, JPEG is applied to each image data subjected to image processing.
The compression processing is performed by the unit 25, and the compressed image data is recorded by the recording unit 26 on a recording medium such as a memory card.

As described above, in the present embodiment, the image pickup elements 15a, 14b,
15b and 15c are provided, and the exposure process of another image sensor is performed during the read process of a certain image sensor, so that the exposure process and the read process are repeatedly performed by a single image sensor as in the related art. In contrast, it is possible to ensure high-speed shooting. Therefore, even if the number of pixels of the image sensor increases and the readout time from the image sensor increases, bracket shooting can be performed at high speed. It is possible to obtain an image of the photographed optimal composition. Also, by using a prism as the light beam splitting means, it is possible to make the optical system compact.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining the disclosed constituent elements. For example, even if some constituent elements are deleted from the disclosed constituent elements, they can be extracted as an invention as long as a predetermined effect can be obtained.

[0049]

According to the present invention, a plurality of image sensors can be operated in parallel by receiving a plurality of divided subject luminous fluxes by the plurality of image sensors, so that continuous shooting or bracket shooting can be performed. It can be performed at high speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an electronic camera according to an embodiment of the present invention.

FIG. 2 is a timing chart showing an operation example of the electronic camera according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a modified example of the electronic camera according to the embodiment of the present invention.

FIG. 4 is a block diagram showing a modification of the electronic camera according to the embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a main part of a modified example of the electronic camera according to the embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a main part of a modification of the electronic camera according to the embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a main part of a modification of the electronic camera according to the embodiment of the present invention.

FIG. 8 is a timing chart showing an operation example of the electronic camera according to the second embodiment of the present invention.

FIG. 9 is a timing chart showing an operation example of the electronic camera according to the third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Photographing lens part 12 ... Aperture 13 ... Aperture control part 14 ... Prism part 14a, 14b, 14c, 14d, 14e ... Emission surface 15a, 15b, 15c ... Image sensor 16a, 16b, 16c ... Imaging part 17, 17a, 17b ... SRAM 18 ... Main CPU 19 ... Bus 20 ... Flash memory 21 ... Sub CPU 22 ... Operation unit 23 ... SDRAM 24 ... Signal processor unit 25 ... JPEG unit 26 ... Recording unit 27 ... LCD display unit 28 ... LCD drive unit 31 ... Phase Detection element 31a Photodetector 31b Separator lens 32 Amplifier 33 Defocus amount calculator 41, 41a, 41b Half mirror

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 7/00 G03B 19/02 2H054 17/00 H04N 101: 00 5C022 19/02 G02B 7/11 Z // H04N 101: 00 G03B 3/00 A F-term (reference) 2H002 GA06 GA08 JA07 2H011 AA03 BA21 BB01 BB02 2H020 MB00 MD08 MD09 2H042 CA08 CA10 CA14 CA17 2H051 AA00 BA02 CB14 CB20 2H054 AA01 BB02 AC07 AC04

Claims (7)

[Claims] A photographic lens unit; a light beam splitting unit for splitting a subject light beam passing through the shooting lens unit into a plurality of light beams; and a plurality of light source units provided to receive the plurality of subject light beams from the light beam splitting unit. And an imaging device for causing the imaging device to perform an exposure operation, outputting an image signal photoelectrically converted by the imaging device as image data, and sequentially shifting timings of the exposure operations of the plurality of imaging devices. An electronic camera, comprising: imaging control means for controlling the imaging means so that continuous imaging is performed. 2. The light beam splitting means is a prism unit for splitting an incident light beam into three light beams and emitting the light beams, and the image pickup devices are provided on three emission surfaces of the prism unit, respectively. 2. The electronic camera according to 1. 3. The light beam splitting means is a prism unit for splitting an incident light beam into three light beams and outputting the divided light beams. The plurality of image pickup devices are provided on two output surfaces of the prism unit, respectively, and focus detection is performed. 2. The electronic camera according to claim 1, wherein the detection element is provided on another emission surface. 4. The light beam splitting means is a prism unit that splits an incident light beam into three beams and emits the light beams. The plurality of image sensors are provided on two emission surfaces of the prism unit, respectively, and the number of pixels is smaller than that of the image sensor. 2. The electronic camera according to claim 1, wherein a small number of imaging devices for capturing moving images are provided on another emission surface. 5. A photographing lens unit, a light beam dividing unit for dividing a subject light beam passing through the photographing lens unit into a plurality of light beams, and a plurality of light sources provided to receive the plurality of subject light beams from the light beam dividing unit. An imaging device for performing an exposure operation on the imaging device and outputting an image signal photoelectrically converted by the imaging device as image data; and simultaneously photographing the plurality of imaging devices with different exposure conditions. An electronic camera, comprising: imaging control means for controlling the imaging means so that the image processing is performed. 6. The light beam splitting means is a prism unit that splits an incident light beam into three light beams and emits the divided light beams, and the image pickup devices are provided on three emission surfaces of the prism unit, respectively. 6. The electronic camera according to 5. 7. A photographing lens unit, a light beam dividing unit for dividing a subject light beam passing through the photographing lens unit into a plurality of light beams, and a plurality of light beams provided to receive the plurality of subject light beams from the light beam dividing unit. An image sensor, aperture means for changing the aperture diameter to limit the amount of light incident on the image sensor, and causing the image sensor to perform an exposure operation, and converting an image signal photoelectrically converted by the image sensor into image data. Imaging means for outputting, and imaging control means for controlling the imaging means so as to perform imaging by sequentially changing the aperture diameter of the aperture means and sequentially shifting the exposure operation timing of the plurality of imaging elements. An electronic camera, characterized in that: