Digital Camera Patent AbstractA digital camera provided with an optical zoom function and an electronic
zoom function. In accordance with a specified photographic magnification,
a magnification setting section selects a first magnification from
a plurality of fixed magnification values which has been set in
advance and sets the optical zoom function thereto, and sets a second
magnification at the electronic zoom function such that, when the
optical zoom function and the electronic zoom function are combined,
an image of the specified photographic magnification is obtained.
A settable range of magnifications that can be provided by the optical
zoom function is constituted by a plurality of sub-regions which
form portions of that range. For each sub-region, one magnification
value included in that sub-region is selected in advance to serve
as the fixed magnification. Consequently, power consumption during
zooming can be reduced, and a time difference between a time of
instructing photography and a time of actual photography can be
shortened.
Digital Camera Patent ClaimsWhat is claimed is:
1. A digital camera including an optical zoom function and an electronic
zoom function, the two functions providing zooming in accordance
with magnifications that are set for the two functions, and by combining
the two functions, the digital camera being capable of providing
image data which represents a subject image in accordance with a
specified photographic magnification, and the digital camera comprising:
a zoom operation section for operating to specify the photographic
magnification of the subject image; and a magnification setting
section which, in accordance with the specified photographic magnification,
selects a first magnification from a plurality of fixed magnification
values which have been set in advance and sets the first magnification
at the optical zoom function, and sets a second magnification at
the electronic zoom function such that the optical zoom function
and the electronic zoom function, when combined, provide an image
of the specified photographic magnification, wherein a settable
range of magnifications that can be provided by the optical zoom
function is constituted by a plurality of sub-regions which form
portions of the range and, for each of the sub-regions, a single
magnification value, which is included in the sub-region, is set
in advance as one of the fixed magnification values.
2. The digital camera of claim 1, further comprising an image-sensing
device which generates image data representing the subject image.
3. The digital camera of claim 2, further comprising an optical
system which projects an optical image of the subject on the image-sensing
device, the optical zoom function being provided by relatively moving
at least a portion of the optical system.
4. The digital camera of claim 3, wherein the optical system comprises
at least one lens, and the digital camera further includes a moving
mechanism for relatively moving the at least one lens.
5. The digital camera of claim 2, further comprising a data processing
section which processes the image data generated by the image-sensing
device for generating image data, which represents images, which
differ at least in size, the electronic zoom function being provided
by this processing.
6. The digital camera of claim 1, wherein, on the basis of the
specified photographic magnification, the magnification setting
section chooses one of the sub-regions that includes the value of
the specified photographic magnification and selects the fixed magnification
that has been set for that sub-region.
7. The digital camera of claim 1, further comprising a display
section for monitor-displaying the subject image, the subject image
being displayed at the display section in accordance with the specified
photographic magnification.
8. The digital camera of claim 1, further comprising a photographic
operation section for instructing execution of photography, wherein,
at a time when the execution of photography has been instructed,
the magnification setting section assigns the specified photographic
magnification to the optical zoom function.
9. The digital camera of claim 8, wherein the digital camera accommodates
a recording medium for storing an image, the photographic operation
section gives a first instruction and a second instruction for executing
photography, the first instruction causing preparation for photography
and the second instruction causing recording of the image data to
the recording medium, and the magnification setting section assigns
the specified photographic magnification to the optical zoom function
when the photographic operation section causes the preparation for
photography.
10. The digital camera of claim 9, wherein the photographic operation
section comprises a button which includes a function for, consequent
to pressing-operation by an operator when photography is to be executed,
commencing the execution of photography, the first instruction being
carried out when the button is pressed to an intermediate position
and the second instruction being carried out when the button is
pressed beyond the intermediate position to a final pressing position.
11. The digital camera of claim 1, wherein a difference between
the fixed magnification values, which are adjacent to each other,
is less than half of each zoom range of the sub-regions corresponding
to those fixed magnification values.
12. The digital camera of claim 1, wherein a difference between
the fixed magnification values, which are adjacent to each other,
is greater than half of each zoom range of the sub-regions corresponding
to those fixed magnification values and less than each of the zoom
ranges.
13. The digital camera of claim 1, wherein the plurality of sub-regions
includes a portion at which two of the sub-regions, which are adjacent
to each other, overlap one another.
14. A digital camera comprising: an optical system which projects
an optical image of a subject at a first magnification, the first
magnification being set at the optical system; an image-sensing
device which generates image data representing the subject image
in accordance with the optical image, the optical image being projected
onto the image-sensing device; a data processing section which performs
magnification processing on the image data generated by the image-sensing
device on the basis of a second magnification that is set, and which
data processing section is capable of generating image data representing
images which differ at least in size; a zoom operation section for
operating to specify a photographic magnification of the subject
image; and a magnification setting section which, in accordance
with the specified photographic magnification, selects and sets
the first magnification from a plurality of fixed magnification
values which have been set in advance and sets the second magnification
such that the image data generated by the data processing section
represents an image of the specified photographic magnification,
wherein a settable range of photographic magnifications is constituted
by a plurality of sub-regions which form portions of the range and,
for each of the sub-regions, a single magnification value which
is included in the sub-region is set in advance as one of the fixed
magnification values.
15. The digital camera of claim 14, wherein the optical system
comprises at least one lens, and the digital camera further includes
a moving mechanism for relatively moving the at least one lens.
16. The digital camera of claim 14, wherein, on the basis of the
specified photographic magnification, the magnification setting
section chooses one of the sub-regions that includes the value of
the specified photographic magnification and selects the fixed magnification
that has been set for that sub-region.
17. The digital camera of claim 14, further comprising a display
section for monitor-displaying the subject image, the subject image
being displayed at the display section in accordance with the specified
photographic magnification.
18. A method for setting a photographic magnification of a digital
camera, the digital camera including an optical zoom function and
an electronic zoom function, the two functions providing zooming
in accordance with magnifications that are set for the two functions,
and by combining the two functions, the digital camera being capable
of providing image data which represents a subject image in accordance
with a specified photographic magnification by, the method comprising
the steps of: providing a photographic magnification value for a
subject image; and in accordance with the provided photographic
magnification value, selecting a first magnification from a plurality
of fixed magnification values which have been set in advance and
setting the first magnification at the optical zoom function, and
setting a second magnification at the electronic zoom function such
that the optical zoom function and the electronic zoom function,
when combined, provide an image at the provided photographic magnification
value; wherein a settable range of magnifications that can be provided
by the optical zoom function is constituted by a plurality of sub-regions
which form portions of the range and, for each of the sub-regions,
a single magnification value which is included in the sub-region
is set in advance as one of the fixed magnification value. Digital Camera Patent DescriptionBACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital camera, and more particularly
to a digital camera which is provided with an optical zoom function
and an electronic zoom function.
2. Description of the Related Art
In recent years, digital cameras, such as digital still cameras,
digital video cameras and the like, that are provided with both
an optical zoom function and an electronic zoom function have become
widespread.
Conventionally, in such a digital camera, from the viewpoint of
maintaining quality of images obtained by photography (subject images),
zooming has been implemented by the optical zoom function in a range
of photographic magnification corresponding to the optical zoom
function, and zooming with the electronic zoom function has been
implemented in cases in which zooming beyond that range was to be
implemented. Note that, although an electronic zoom function may
also be referred to as a digital zoom function, the term "electronic
zoom function" is used throughout the present specification.
Now, when zooming is to be implemented by an optical zoom function,
it is necessary to move a lens that is provided at the digital camera
in an optical axis direction and change a focusing distance which
depends on that lens. Ordinarily, a motor such as a stepper motor
or the like (below referred to as a "zoom motor") is employed
as moving means therefor (see Japanese Patent Application Laid-Open
(JP-A) Nos. 2000-224455, 2001-211373 and the like).
Consequently, there has been a problem with this kind of digital
camera, in that the zoom motor is driven when zooming is to be implemented
within a range of photographic magnification corresponding to the
optical zoom function, and therefore power consumption is high.
As a result, when the power consumption during zooming is large,
there is a problem in that, assuming that the digital camera is
being used in a mobile environment, because of the effect of the
electric power being drawn by the zoom motor in a digital camera
that employs a battery as a power source, a number of photographic
images that can be captured is decreased. Further problems and the
like may arise, such as, in a digital camera which is capable of
executing multi-tasking of various internal processes for the purpose
of increasing the speed of photography, it being necessary in some
cases to apply a limit to the internal processes that can be concurrently
implemented because of the effect of the electric power that is
drawn by the zoom motor.
Accordingly, in order to solve the above-described problems with
the power consumption being large during zooming, JP-A No. 2000-111785
has proposed a technique of reducing power consumption during zooming
of a zoom mechanism of a lens by, at a point in time before photography,
monitor-displaying a subject image for which electronic zoom processing
has been carried out in accordance with a focusing distance specified
by a zoom button, without operating the zoom mechanism of the lens,
and using the zoom mechanism to set the lens to the focusing distance
that has been specified only at a time of photography.
In the technique described in JP-A No. 2000-111785, the power consumption
during zooming can be reduced. However, because the zoom mechanism
is operated only during photography, although there is no problem
if a difference between the photographic magnification that was
set before by electronic zoom processing before photography and
the photographic magnification of the optical zoom that was set
at the time of photography is small, in a case in which this difference
is large, for example, a case in which the photographic magnification
set by the electronic zoom processing is a minimum photographic
magnification and the photographic magnification of the optical
zoom that was set at the time of photography is a maximum photographic
magnification or the like, there is a problem in that a time difference
between a time of instructing photography by pressing-operation
of a release button (a "shutter") and a time of actual
photography becomes large. In cases in which this time difference
is large, operational feedback during photography will seem incongruous
to a photographer, in addition to which good "shutter chance"
moments may be missed, and these are serious problems.
SUMMARY OF THE INVENTION
The present invention has been devised in order to solve the problems
described above, and an object of the present invention is to provide
a digital camera which is capable of shortening a time difference
between a time of instructing photography and a time of actual photography,
while reducing power consumption at times of zooming.
A first aspect of the present invention for achieving the object
described above is a digital camera provided with an optical zoom
function and an electronic zoom function, the two functions providing
zooming in accordance with magnifications that are set for the two
functions, and by combining the two functions, the digital camera
being capable of providing image data which represents a subject
image in accordance with a specified photographic magnification,
and the digital camera including: a zoom operation section for operation
to specify the photographic magnification of the subject image;
and a magnification setting section which, in accordance with the
specified photographic magnification, selects a first magnification
from a plurality of fixed magnification values which have been set
in advance and sets the first magnification at the optical zoom
function, and sets a second magnification at the electronic zoom
function such that the optical zoom function and the electronic
zoom function, when combined, provide an image of the specified
photographic magnification, wherein a settable range of magnifications
that can be provided by the optical zoom function is constituted
by a plurality of sub-regions which form portions of the range and,
for each of the sub-regions, a single magnification value which
is included in the sub-region is set in advance as one of the fixed
magnification values.
According to the digital camera of the first aspect of the present
invention, the zoom operation section is operated when the photographic
magnification of the subject image is to be specified. Specifically,
the zoom operation section of the present invention corresponds
to a zoom button, which is commonly provided at a digital camera
in which a zoom function is incorporated.
In the digital camera of the first aspect of the present invention,
an optical system that is provided with an image-sensing device,
which generates image data representing the subject image, may be
provided. In such a case, the optical system projects an optical
image of the subject on the image-sensing device, and the optical
zoom function is provided by relatively moving at least a portion
of the optical system.
A data processing section may be provided in the digital camera
of the first aspect of the present invention. In such a case, the
data processing section processes the image data that has been generated
by the image-sensing device, and provides the electronic zoom function
by generating image data, which represent images, which are different
at least in size.
In the digital camera of the first aspect of the present invention,
the optical system may include at least one lens. In such a case,
a moving mechanism relatively moves the at least one lens.
The above-mentioned lens may be structured by just one lens, or
may be structured by a plurality of lenses. The above-mentioned
moving mechanism corresponds to a previously mentioned zoom motor.
The moving mechanism can be any suitable mechanism as long as that
mechanism is electrically capable of moving a lens in the optical
axis direction, such as a motor (such as a stepper motor or the
like), a solenoid or the like. In a case in which the lens is structured
by a plurality of lenses, the moving mechanism operates as a mechanism
which moves at least one of the plurality of lenses in the optical
axis direction.
In the digital camera of the first aspect of the present invention,
the magnification setting section may, on the basis of the photographic
magnification that is set, select a sub-region which includes that
value, and select a fixed magnification that is specified for that
sub-region.
In the digital camera of the first aspect of the present invention,
a display section for monitor-display of the subject image may be
provided. In such a case, a subject image corresponding to the photographic
magnification that has been specified is displayed thereat. Various
kinds of display, such as a liquid crystal display, an organic EL
(electroluminescent) display, a plasma display, a CRT display or
the like may be employed as the display section.
In the digital camera of the first aspect of the present invention,
a photographic operation section for instructing the execution of
photography may be provided. In such a case, when the execution
of photography is instructed, the magnification setting section
assigns the photographic magnification value that has been specified
to the optical zoom function. That is, the photographic operation
section of the present invention corresponds to a release button,
which is commonly provided at a digital camera in which a zoom function
is incorporated.
Now, in a digital camera of the present invention, in accordance
with the photographic magnification that is specified by the magnification
setting section, a first magnification is selected from a plurality
of fixed magnification values which have been set in advance, and
is set at the optical zoom function. A second magnification is set
at the electronic zoom function such that the optical zoom function
and the electronic zoom function, when combined, provide an image
of the specified photographic magnification. A settable range of
magnification that can be provided by the optical zoom function
is constituted by a plurality of sub-regions which form portions
of this range. For each sub-region, a single magnification value
which is included in that region is set in advance as one of the
aforementioned fixed magnification values.
Specifically, when zooming is to be carried out by the magnification
setting section of the present invention consequent to an operation
of the zoom operation section, if this operation is carried out
within a sub-region that includes the photographic magnification
represented by this operation, photographic magnification by the
optical zoom function is set at the fixed magnification value that
was set in advance for that sub-region and processing to set the
photographic magnification in accordance with the operation of the
zoom operation section is carried out by the electronic zoom function,
such that an image of that photographic magnification is obtained.
In a case in which the photographic magnifications represented by
the operation on the zoom operation section shifts out of a sub-region,
the photographic magnification of the optical zoom is changed so
as to attain the fixed magnification value that has been set for
the sub-region that includes the end-point of the shift, and setting
of the photographic magnification within this sub-region is carried
out by the electronic zoom function.
Thus, in a digital camera relating to the present invention, zooming
within a sub-region is carried out only by electronic zoom processing,
and only in a case of moving outside a sub-region is the photographic
magnification shifted to a fixed magnification value in a neighboring
sub-region by the optical zoom function. Therefore, a number of
movements of the lens by the moving mechanism can be greatly reduced
in comparison with a case in which zooming is always carried out
by an optical zoom function. As a result, power consumption at times
of zooming can be greatly reduced.
Here, in the digital camera of the present invention, in accordance
with the photographic magnification that has been specified, the
first magnification is selected from the plurality of fixed magnification
values that have been set in advance and is set at the optical zoom
function. The second magnification is set at the electronic zoom
function such that, when the optical zoom function is combined with
the electronic zoom function, an image of the photographic magnification
that has been specified is obtained. The settable range of magnification
that can be provided by the optical zoom function is constituted
by the plurality of sub-regions that form portions of this range.
For each sub-region, a single magnification value included in that
region is set in advance as the aforementioned fixed magnification
value.
Thus, in a digital camera relating to the present invention, on
the basis of the specified photographic magnification, the magnification
setting section chooses the sub-region that includes that value,
selects the fixed magnification that is specified for that sub-region
and, when the execution of photography is instructed, the magnification
setting section assigns the specified photographic magnification
to the optical zoom function. Therefore, in comparison with a case
in which the photographic magnification has to be set to a photographic
magnification in another sub-region by the optical zoom function,
the photographic magnification of the optical zoom function can
be set to the desired photographic magnification in a short time,
and a time difference between a time of instructing photography
by pressing-operation of the photographic operation section and
a time of actual photography can be made shorter.
In the digital camera of the first aspect of the present invention,
the plurality of sub-regions may include a portion at which two
mutually adjacent sub-regions overlap one another.
As a result, the occurrence of hunting, in which the fixed magnification
value of the optical zoom function is changed many times when zooming
operations in accordance with operation of the zoom operation section
cross a boundary between the sub-regions many times, can be prevented.
In the digital camera of the first aspect of the present invention,
the photographic operation section may give a first instruction
and a second instruction for executing photography, the first instruction
causing preparation for photography and the second instruction causing
recording of the image data to a recording medium, and the magnification
setting section may assign the specified photographic magnification
to the optical zoom function when the photographic operation section
causes the preparation for photography.
Consequently, the photographic magnification of the optical zoom
function can be set to a final magnification in a preparation step
immediately before the execution of photography. As a result, the
time difference between the time of instructing photography and
the time of actual photography can be reliably made shorter.
A digital camera of a second aspect of the present invention includes:
an optical system which projects an optical image of a subject at
a first magnification, the first magnification being set at the
optical system; an image-sensing device which generates image data
representing the subject image in accordance with the optical image,
the optical image being projected onto the image-sensing device;
a data processing section which performs magnification processing
on the image data generated by the image-sensing device on the basis
of a second magnification that is set, and which is capable of generating
image data representing images which differ at least in size; a
zoom operation section for operating to specify a photographic magnification
of the subject image; and a magnification setting section which,
in accordance with the specified photographic magnification, selects
and sets the first magnification from a plurality of fixed magnification
values which have been set in advance and sets the second magnification
such that the image data generated by the data processing section
represents an image of the specified photographic magnification,
wherein a settable range of photographic magnifications is constituted
by a plurality of sub-regions which form portions of the range and,
for each of the sub-regions, a single magnification value which
is included in the sub-region is set in advance as one of the fixed
magnification values.
A third aspect of the present invention is a method for setting
a photographic magnification of a digital camera, the digital camera
including an optical zoom function and an electronic zoom function,
the two functions providing zooming in accordance with magnifications
that are set for the two functions, and by combining the two functions,
the digital camera being capable of for providing image data which
represents a subject image in accordance with a specified photographic
magnification by, the method including the steps of: providing a
photographic magnification value for a subject image; and in accordance
with the provided photographic magnification value, selecting a
first magnification from a plurality of fixed magnification values
which have been set in advance and setting the first magnification
at the optical zoom function, and setting a second magnification
at the electronic zoom function such that the optical zoom function
and the electronic zoom function, when combined, provide an image
at the provided photographic magnification value; wherein a settable
range of magnifications that can be provided by the optical zoom
function is constituted by a plurality of sub-regions which form
portions of the range and, for each of the sub-regions, a single
magnification value which is included in the sub-region is set in
advance as one of the fixed magnification value.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is external views showing the exterior of a digital camera
10 relating to an embodiment of the present invention.
FIG. 2 is a block diagram showing structure of an electric system
of the digital camera 10 relating to the embodiment.
FIG. 3 is a flowchart showing flow of photography processing which
is executed at the digital camera 10 relating to the embodiment.
FIG. 4 is an explanatory diagram for explaining the photography
processing relating to the embodiment.
FIG. 5 is another explanatory diagram for explaining the photography
processing relating to the embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Below, an embodiment of the present invention will be explained
in detail with reference to the drawings. For the present embodiment,
a digital camera of the present invention is described for a mode
in a case in which a digital still camera (below referred to simply
as "the digital camera") is employed. Firstly, with reference
to FIG. 1, external structure of the digital camera 10 relating
to the present embodiment will be described.
As is shown in FIG. 1, a lens 12 and a viewfinder 70 are provided
at a front face of the digital camera 10. The lens 12 is for focusing
a subject image, and the viewfinder 70 is used for determining the
composition of the subject to be photographed. A release button
(a "shutter") 60 and a power switch 66 are provided at
an upper face of the digital camera 10. The release button 60 is
pressed for operation by a camera operator when photography is to
be executed.
The release button 60 relating to the present embodiment is structured
to be capable of detecting pressing operation in two steps: a state
in which the release button 60 is pressed to an intermediate position
(below referred to as a "half-pressed state") and a state
in which the release button 60 is pressed down beyond the intermediate
position to a final pressing position (below referred to as a "fully
pressed state").
When the release button 60 of the digital camera 10 relating to
the present embodiment is put into the half-pressed state, an exposure
state (shutter speed and aperture conditions) is specified by an
AE (automatic exposure) function, and focusing is controlled by
an AF (auto focus) function. Thereafter, when the release button
60 is set to the fully pressed state, exposure (photography) is
carried out.
At a back face of the digital camera 10, an eyepiece of the aforementioned
viewfinder 70, a liquid crystal display (below referred to as an
"LCD") 30, a mode-switching switch 62, a cross-cursor
button 64 and a zoom button 68 are provided. The LCD 30 is for showing
subject images represented by digital image data obtained by photography,
and various menus, messages and the like. The mode-switching switch
62 is operated for setting a mode to either of a photography mode,
which is a mode for carrying out photography, and a playback mode,
which is a mode for displaying (replaying) the subject images represented
by the digital image data obtained by photography at the LCD 30.
The cross-cursor button 64 is structured to include five keys: four
arrow keys which represent four directions of movement (left, right,
up and down) in a display region of the LCD 30, and a confirmation
key which is positioned at a portion central to the four arrow keys.
The zoom button 68 is operated when zooming (enlargement or reduction)
of the subject image is to be carried out during photography.
The zoom button 68 is structured to include a telephoto button,
corresponding to the position of the "T" in FIG. 1, and
a wide angle button, corresponding to the position of the "W"
in FIG. 1. The telephoto button is operated when the subject image
is to be enlarged (zooming in), and the wide angle button is operated
when the subject image is to be reduced (zooming out).
A receptacle 72 is provided at a bottom face of the digital camera
10. The receptacle 72 is used for electrically connecting the digital
camera 10 with an external device using a predetermined interface
standard (in the present embodiment, USB (Universal Serial Bus)).
Next, structure of an electrical system of the digital camera 10
relating to the present embodiment will be described with reference
to FIG. 2.
As shown in FIG. 2, the digital camera 10 includes an optical unit
13, a CCD (charge coupled device) 14, a correlated doubled sampling
circuit (below referred to as a "CDS") 16 and an analog/digital
converter (below referred to as an "ADC") 18. The optical
unit 13 is structured to include the aforementioned lens 12. The
CCD 14 is provided at a rear side of an optical axis of the lens
12. The ADC 18 converts inputted analogue signals to digital data.
An output terminal of the CCD 14 is connected to an input terminal
of the CDS 16, and an output terminal of the CDS 16 is connected
to an input terminal of the ADC 18.
Here, correlated doubled sampling processing by the CDS 16 has
the object of alleviating noise (particularly thermal noise) and
the like that is included in output signals of a solid-state image-sensing
device. This processing provides accurate pixel data by taking differences
between the level of a feed-through component, which is included
in output signals of each pixel of the solid-state image-sensing
device, and the levels of the pixel signal components.
The digital camera 10 incorporates a line buffer with a predetermined
capacity and is structured to include an image input controller
20, an image signal processing circuit 22, a compression/decompression
processing circuit 24 and a video/LCD encoder 28. The image input
controller 20 carries out control to directly store the digital
image data that is inputted in a predetermined region of a second
memory 40, which is described later. The image signal processing
circuit 22 implements various kinds of image processing on the digital
image data. The compression/decompression processing circuit 24
implements compression processing on the digital image data, into
a predetermined compression format, and implements decompression
processing on the digital image data that has been compression-processed,
in accordance with the compression format. The video/LCD encoder
28 generates signals for displaying images represented by digital
image data, menu screens and the like at the LCD 30 and supplies
these signals to the LCD 30, and generates image signals (NTSC signals
in the present embodiment) representing images that are displayed
at the LCD 30 and outputs these image signals to a video output
terminal ("OUT"). An input terminal of the image input
controller 20 is connected to an output terminal of the ADC 18.
Furthermore, the digital camera 10 is structured to include a CPU
(central processing unit) 32, an AF detection circuit 34, an AE/AWB
detection circuit 36, a first memory 38 and the second memory 40.
The CPU 32 administers overall operations of the digital camera
10. The AF detection circuit 34 detects a physical quantity that
is required for operation of the AF function (in the present embodiment,
a contrast value of an image that is obtained by imaging by the
CCD 14). The AE/AWB detection circuit 36 detects a physical quantity
that is required for operation of the AE function and an AWB (automatic
white balance) function (in the present embodiment, a value which
represents brightness of the image obtained by the imaging by the
CCD 14). The first memory 38 is structured by SDRAM (synchronous
dynamic random access memory), and is utilized as a work area during
execution of various processes by the CPU 32, and the like. The
second memory 40 is principally structured by VRAM (video RAM) and
stores the digital image data provided by photography.
The digital camera 10 is structured to further include a media
controller 42 and a USB interface 46. The media controller 42 is
for enabling access of the digital camera 10 to a recording medium
42A, which is structured by a SMART MEDIA (R), and a recording medium
42B at a microdrive. The USB interface 46 is connected to the aforementioned
receptacle 72 and administers communications between the digital
camera 10 and the exterior in accordance with USB standards.
The above-mentioned image input controller 20, image signal processing
circuit 22, compression/decompression processing circuit 24, video/LCD
encoder 28, CPU 32, AF detection circuit 34, AE/AWB detection circuit
36, first memory 38, second memory 40, media controller 42 and USB
interface 46 are all connected to one another via a system bus ("BUS").
Thus, the CPU 32 can implement control of the image input controller
20, the image signal processing circuit 22, the compression/decompression
processing circuit 24, and the video/LCD encoder 28, can implement
acquisition of physical quantities that are detected by the AF detection
circuit 34 and the AE/AWB detection circuit 36, can implement access
to the first memory 38, the second memory 40, the recording medium
42A and the recording medium 42B, and can implement intercommunication
with an external device which is connected to the receptacle 72.
The digital camera 10 is also provided with a timing generator
48, which generates timing signals, principally for driving the
CCD 14, and supplies those timing signals to the CCD 14. An input
terminal of the timing generator 48 is connected to the CPU 32 and
an output terminal of the timing generator 48 is connected to the
CCD 14. Thus, driving of the CCD 14 is controlled by the CPU 32
via the timing generator 48.
An input terminal of a motor driving section 50 is connected to
the CPU 32. An output terminal of the motor driving section 50 is
connected to a zoom motor 13A and a focusing adjustment motor 13B,
which are provided at the optical unit 13.
The lens 12, which is included at the optical unit 13 relating
to the present embodiment, has a plurality of lenses and is structured
to serve as a zoom lens which is capable of alterations of focusing
distance (variations of magnification). The lens 12 is provided
with an unillustrated lens-driving mechanism. The zoom motor 13A
and focusing adjustment motor 13B are included at this lens-driving
mechanism. Thus, the zoom motor 13A and the focusing adjustment
motor 13B are driven by driving signals supplied from the motor
driving section 50 under the control of the CPU 32.
The CPU 32 drive-controls the zoom motor 13A when an optical photographic
magnification is to be altered, and changes the focusing distance
of the lenses included in the optical unit 13.
The CPU 32 carries out focus control by drive-controlling the focusing
adjustment motor 13B so as to maximize a contrast value of an image
that is obtained by imaging by the CCD 14. That is, in the digital
camera 10 relating to the present embodiment, the "TTL"
(through the lens) method, in which the position of a lens is set
so as to maximize contrast of an acquired image, is employed as
a focus control method.
Various buttons and switches, such as the aforementioned release
button 60, mode-switching switch 62, cross-cursor button 64, power
switch 66 and zoom button 68 (which are shown as "operation
section 52" in FIG. 2) are also connected to the CPU 32. The
CPU 32 is capable of constantly monitoring operation states of these
buttons and switches.
The lens 12 corresponds to a lens of the present invention, the
LCD 30 corresponds to a display section of the present invention,
the zoom motor 13A corresponds to a moving mechanism of the present
invention, the zoom button 68 corresponds to a zoom operation section
of the present invention, the release button 60 corresponds to a
photographic operation section of the present invention, and the
CPU 32 corresponds to a magnification setting section and a data
processing section of the present invention.
Next, operation of the digital camera 10 relating to the present
embodiment will be described. First, general operations of the digital
camera 10 at a time of photography will be briefly described.
(1) Signals representing a subject image, which are outputted from
the CCD 14 consequent to imaging via the optical unit 13, are sequentially
inputted to the CDS 16 and correlated doubled sampling processing
is executed. Then the signals are sequentially inputted to the ADC
18. The ADC 18 converts R (red), G (green) and B (blue) signals
that have been inputted thereto from the CDS 16 to respective 12-bit
R, G and B signals (digital image data), and outputs these to the
image input controller 20.
(2) Digital image data that has been sequentially inputted to a
line buffer, which is incorporated at the image input controller
20, from the ADC 18 is accumulated and temporarily stored in a predetermined
region of the second memory 40.
(3) The digital image data that has been stored at the predetermined
region of the second memory 40 is read out by the image signal processing
circuit 22, under the control of the CPU 32. White balance adjustment
is carried out by setting digital gain on the digital image data
in accordance with a physical quantity that has been detected by
the AE/AWB detection circuit 36, and gamma processing and sharpness
processing are carried out and 8-bit digital image data is generated.
Furthermore, YC signal processing is executed to generate luminance
signals Y and chroma signals Cr and Cb (below referred to as "YC
signals"), and the YC signals are stored at a region of the
second memory 40 which is different from the aforementioned predetermined
region.
(4) When the release button 60 is put into the fully pressed state
by a camera operator, YC signals that are stored at the second memory
40 at that point in time are compressed into a predetermined compression
format (JPEG format in the present embodiment) by the compression/decompression
processing circuit 24, and then recorded to the recording medium
42A via the media controller 42.
The LCD 30 relating to the present embodiment is structured to
display a moving image (a through-image) which is obtained by continuous
imaging by the CCD 14, and to be employable as a viewfinder. In
a case in which the LCD 30 is thus employed as a viewfinder, in
the above stage (2), a simple YC signal conversion is executed on
the digital image data that is stored in the second memory 40, the
YC signals that have been generated are then stored in the predetermined
region of the second memory 40, and these YC signals in the second
memory 40 are sequentially outputted to the LCD 30 via the video/LCD
encoder 28. Accordingly, the through-image is displayed at the LCD
30. This processing is referred to as stage (2').
Now, the CPU 32 relating to the present embodiment is structured
to be capable of multi-task processing, and implements the processing
of stages (1) and (2') in parallel with execution of the processing
of the above stage, (3) and (4). Thus, while the user observes the
through-image which is displayed at the LCD 30 by these operations,
the user decides on the composition of a subsequent photograph,
and carries out preparatory tasks, such as zooming by operation
of the zoom button 68 and the like.
Next, of processing that is executed at the digital camera 10 during
photography, a portion of the processing that particularly relates
to the present invention will be described in detail, with reference
to FIGS. 3 to 5. FIG. 3 is a flowchart showing flow of a portion
of photography processing which is executed at the CPU 32 of the
digital camera 10 when the photography mode has been selected by
the mode-switching switch 62, which portion particularly relates
to the present invention. FIGS. 4 and 5 are explanatory diagrams
for explanation of the photography processing. Here, in order to
avoid confusion, the general operations of the digital camera 10
that have already been described are omitted from the explanation
as much as possible.
In step 100 of FIG. 3, it is judged whether or not the zoom button
68 is being pressed for operation. In the case of a positive judgement,
the process advances to step 102, and a photographic magnification
SZ of the subject image is deduced in accordance with operation
of the zoom button 68. Here, when the telephoto button of the zoom
button 68 is pressed for operation, the photographic magnification
SZ is deduced by incrementing the photographic magnification at
that point in time by a predetermined value (in the present embodiment,
0.1), and when the wide angle button of the zoom button 68 is pressed
for operation, the photographic magnification SZ is deduced by decrementing
the photographic magnification SZ at that point in time by a predetermined
value (in the present embodiment, 0.1).
In a subsequent step 104, it is judged whether or not a value which
is deduced by subtracting a photographic magnification OZ of the
optical zoom at this point in time from the photographic magnification
SZ exceeds a value .DELTA.X (which is 0.5 in the present embodiment).
If this judgement is positive, the process advances to step 106,
and the photographic magnification OZ is increased by the amount
of .DELTA.X. Then, in step 108, the zoom motor 13A is controlled,
via the motor driving section 50, such that the photographic magnification
of the optical zoom attains the photographic magnification OZ that
has been obtained by the processing of step 106. Thereafter, the
process advances to step 116.
If the judgement in step 104 is negative, that is, if the photographic
magnification SZ minus the photographic magnification OZ is less
than or equal to .DELTA.X, the process advances to step 110, and
it is determined whether or not the photographic magnification SZ
minus the photographic magnification OZ is less than -.DELTA.X.
If this judgement is positive, the process advances to step 112,
and the photographic magnification OZ is decreased by the amount
of .DELTA.X. Then, in step 114, the zoom motor 13A is controlled,
via the motor driving section 50, such that the photographic magnification
of the optical zoom attains the photographic magnification OZ that
has been obtained by the processing of step 112. Thereafter, the
process advances to step 116. Note that in a case in which the judgement
in the above-mentioned step 110 is negative, the process advances
to step 116 without executing the processing of steps 112 and 114.
In step 116, a photographic magnification DZ of the electronic
zoom is deduced by the following equation (1).
##EQU00001##
In a subsequent step 118, electronic zoom processing is carried
out on the digital image data that corresponds to the subject image
that is to be displayed at the LCD 30 such that the photographic
magnification of the electronic zoom attains the photographic magnification
DZ which has been found in step 116. Thereafter, the process returns
to the aforementioned step 100.
In the electronic zoom processing relating to the present embodiment
described above, in a case in which the electronic zoom photographic
magnification DZ exceeds 1, pixel data which cannot be provided
by imaging by the CCD 14 (by pixel units of the digital image data)
is implemented by creating new data in accordance with the magnitude
of the photographic magnification DZ, by interpolation processing.
Further, in a case in which the electronic zoom photographic magnification
DZ is less than 1, pixel units that correspond to the magnitude
of the photographic magnification DZ are implemented by thinning-out
processing of the digital image data that is provided by imaging
by the CCD 14.
Now, in a case in which the judgement in the above-mentioned step
100 is negative, that is, in a case in which the zoom button 68
is not being pressed for operation, the process advances to step
120, and it is judged whether or not the release button 60 has been
put into the half-pressed state. If this judgement is negative,
the process returns to step 100, but if this judgement is positive,
the process advances to step 122.
In step 122, the zoom motor 13A is controlled, via the motor driving
section 50, such that the photographic magnification of the optical
zoom attains the photographic magnification SZ. In a subsequent
step 124, it is judged whether or not the release button 60 has
been put into the fully pressed state. If this judgement is negative,
the process advances to step 126 and it is judged whether or not
the release button 60 has been returned to an unpressed position.
If this judgement is negative, the process returns to step 124,
but if this judgement is positive, the process returns to step 100.
Alternatively, if the judgement in step 124 is positive, then the
process advances to step 128.
By repeating the processing of steps 100 to 126, display at the
LCD 30 of a subject image with a photographic magnification corresponding
to operations of the zoom button 68 is implemented by the processing
of steps 100 to 118 while the zoom button 68 is being operated by
a user, and at a time when the release button 60 has been put into
the half-pressed state by the user, the optical zoom photographic
magnification OZ is set such that the photographic magnification
that has been specified in accordance with operations by the zoom
button 68 up to this moment is attained.
Hence, in a case in which the release button 60 returns to the
unpressed position without continuing on from the half-pressed state
to be put into the fully pressed state, it is considered that photography
is not to be carried out, and the process returns to step 100. The
process waits for further pressing operation of the zoom button
68 or of the release button 60. In a case in which the release button
60 is advanced from the half-pressed state and continues on to the
fully pressed state, photography it is considered that photography
is to be carried out, and the process advances to step 128.
In step 128, the YC signals that are stored in the second memory
40 at this point in time are compressed into the predetermined compression
format (JPEG format in the present embodiment) by the compression/decompression
processing circuit 24, and then recorded to the recording medium
42A via the media controller 42. In a subsequent step 130, it is
judged whether or not the setting of the mode-switching switch 62
has been switched into playback mode, and thus it is judged whether
or not the photography processing is to finish. If this judgement
is negative, the process returns to step 100, and when this judgement
becomes positive, the photographic processing is terminated.
As shown in FIG. 4, a settable range of the photographic magnification
OZ of the optical zoom function (in the present embodiment, a range
from 1.0.times.to 3.0.times.) is divided into a plurality of sub-regions
(in the present embodiment, three sub-regions, sub-region A1 to
sub-region A3, which are set to zoom ranges of 2.times..DELTA.X)
and, for each sub-region, a single photographic magnification which
is included in that sub-region (in the present embodiment, photographic
magnifications of 1.5, 2.0 and 2.5, which are photographic magnifications
at mid-points of the sub-regions) is set in advance to serve as
a fixed magnification value. By repeating the processing of steps
100 to 118 of the present photographic processing, the zoom motor
13A is controlled such that the photographic magnification of the
optical zoom function is set to the fixed magnification value of
the sub-region which includes the photographic magnification SZ
corresponding to operations on the zoom button 68, and the photographic
magnification DZ of the electronic zoom function is set such that,
in combination with the fixed magnification value, the photographic
magnification of the subject image that is displayed at the LCD
30 is at the photographic magnification SZ corresponding to operations
on the zoom button 68.
Accordingly, as shown in FIG. 5, which is an example, when zooming
is carried out by operations on the zoom button 68 by a user, while
the operations are carried out within a sub-region that encompasses
the photographic magnifications represented by these operations
(in FIG. 5, the sub-region A3), the optical zoom photographic magnification
OZ is fixedly set at the fixed magnification value that is specified
for that sub-region, and processing for setting a photographic magnification
of a subject image which is monitor-displayed at the LCD 30 to the
photographic magnification SZ is carried out only by electronic
zoom processing. Further, when the photographic magnification SZ
represented by operations on the zoom button 68 transits to outside
the sub-region mentioned above, the optical zoom photographic magnification
OZ is changed to the fixed magnification value that is specified
for a sub-region that includes the end-point of this transition,
and setting of photographic magnifications within this sub-region
is carried out by electronic zoom processing.
Thus, in the digital camera 10 relating to the present invention,
zooming within each sub-region is implemented only by electronic
zoom processing, and only when the photographic magnification moves
outside a sub-region is the optical zoom photographic magnification
OZ moved to the fixed magnification value of a neighboring sub-region.
Therefore, a number of driving operations of the zoom motor 13A
can be greatly reduced in comparison with a case in which zooming
is always implemented by the optical zoom function. Consequently,
in the digital camera 10 relating to the present embodiment, power
consumption at times of zooming can be greatly reduced.
As a result, limits to multi-task processing due to limits of capacity
of an unillustrated battery can be moderated, zooming processing
can be carried out without interrupting the processing of the aforementioned
stages (3) and (4), and it is possible to greatly increase a number
of successive photographic images.
In addition, in the digital camera 10 relating to the present embodiment,
when the release button 60 is put into the half-pressed state by
a user, by the processing of steps 120 and 122, the optical zoom
photographic magnification OZ is promptly shifted to the photographic
magnification SZ that has been specified by the repeated processing
of steps 100 to 118. At this time, because the optical zoom photographic
magnification OZ has been set to the fixed magnification value that
had been set in advance for the sub-region that includes the photographic
magnification SZ, in comparison with a case in which the optical
zoom photographic magnification OZ is to be set to a photographic
magnification in another sub-region, the optical zoom photographic
magnification OZ can be set to the desired photographic magnification
in a short time, and a time difference between the time of pressing-operation
of the release button 60 and a time of actual photography can be
made shorter.
As is described in detail above, with the digital camera 10 relating
to the present embodiment, the settable range of photographic magnifications
according to the optical zoom function is divided into the plurality
of sub-regions and, for each sub-region, a single photographic magnification
included in the sub-region is set in advance as the fixed magnification
value thereof. A photographic magnification according to the optical
zoom function is controlled so as to attain the fixed photographic
magnification of a sub-region that includes a photographic magnification
SZ that corresponds to operations on the zoom button 68, and a photographic
magnification DZ according to the electronic zoom is specified such
that the photographic magnification of a subject image attains,
in combination with that fixed magnification value, the photographic
magnification SZ that corresponds to the operations on the zoom
button 68. When the release button 60 is operated, the photographic
magnification OZ according to the optical zoom function is controlled
so as to attain the photographic magnification SZ that corresponds
to the operations on the zoom button 68. Thus, while the power consumption
during zooming is reduced, the time difference between the time
of instructing photography and the time of actual photography can
be made shorter.
Further, in the digital camera 10 relating to the present embodiment,
because the plurality of sub-regions are specified such that portions
of adjacent sub-regions overlap one another, the occurrence of hunting,
in which the fixed magnification value of the optical zoom function
is changed many times when zooming operations in accordance with
operations of the zoom button 68 cross a boundary between adjacent
sub-regions many times, can be prevented.
Further still, in the digital camera 10 relating to the present
embodiment, an apparatus (the release button 60) which instructs
preparation for photography by a first instruction (the half-pressed
state), and records image data to a recording medium by a second
instruction (the fully pressed state) serves as the photographic
operation section of the present invention. When the photographic
operation section is set for preparation for photography, the photographic
magnification of the optical zoom function is assigned so as to
attain the photographic magnification SZ that has been set by the
zoom button 68. Therefore, the photographic magnification of the
optical zoom function can be set to the final magnification in a
preparation step immediately before the execution of photography.
As a result, the time difference between the time of instructing
photography and the time of actual photography can be made shorter.
Note that for the present embodiment a case in which the fixed
magnification values are set to photographic magnifications at mid-points
of the sub-regions has been described. However, the present invention
is not limited thus. The fixed magnification values may be set to
photographic magnifications that are shifted to a high magnification
side or a low magnification side of each sub-region, in accordance
with user requirements, limitations of control and the like. In
such a case, the same effects as with the present embodiment can
be implemented. Furthermore, in such a case, if the fixed magnification
values are set to the lowest photographic magnification of each
sub-region, the electronic zoom processing may be carried out by
interpolation processing alone, without any implementation of thinning-out
processing. Thus, in comparison with the present embodiment, electronic
zoom processing may be carried out more simply.
Further, for the present embodiment, a case in which the fixed
magnification values are set to photographic magnifications at mid-points
of the sub-regions and the differences between mutually adjacent
fixed magnification values are set to be equivalent to half of the
zoom range of each of the sub-regions corresponding to those fixed
magnification values has been described. However, the present invention
is not limited thus. For example, a mode in which the fixed magnification
values are set to photographic magnifications at the mid-points
of the sub-regions and the differences between mutually adjacent
fixed magnification values are set to be smaller than half of the
zoom range of either of the sub-regions corresponding to those fixed
magnification values, a mode in which the fixed magnification values
are set to photographic magnifications at the mid-points of the
sub-regions and the differences between mutually adjacent fixed
magnification values are set to be greater than half of the zoom
range of either of the sub-regions corresponding to those fixed
magnification values but smaller than those zoom ranges, and the
like are also possible. In the former case, overlapping portions
of neighboring sub-regions are greater than in the present embodiment,
and in the latter case, overlapping portions of neighboring sub-regions
are smaller than in the present embodiment. Accordingly, in the
former case, the occurrence of hunting can be prevented more effectively
than in the present embodiment, and in the latter case, the frequency
of changes of the photographic magnification of the optical zoom
during zooming can be reduced, and thus power consumption during
zooming can be reduced.
Further yet, for the present embodiment, a case in which the settable
range of photographic magnification according to the optical zoom
function is divided into three regions has been described. However,
the present invention is not limited thus. Obviously, modes in which
the range is divided into two or more than three sub-regions are
also possible. Here, the greater the number of sub-regions, the
smaller the amount of a change in the optical zoom at the time of
photography. Therefore, when the number of sub-regions is greater,
the time difference between the time of instructing photography
by pressing-operation of the release button 60 and the time of actual
photography can be made shorter. However, because the frequency
of changes in the photographic magnification of the optical zoom
during zooming is increased, power consumption during zooming is
increased.
Thus, there is a trade-off relationship between the time difference
(between the time of instructing photography and the time of actual
photography) and power consumption during zooming, and the number
of sub-regions can be specified as is preferable.
Further again, for the present embodiment, a case in which widths
of the zoom ranges of the sub-regions are the same has been described.
However, the present invention is not limited thus. For example,
depending on the demands of users and the like, the zoom range widths
of the sub-regions may be set to be different. In such a case, the
user demands and the like can be met. Thus, a zoom function of extremely
high versatility can be realized.
Further yet, for the present embodiment, a case has been described
in which the sub-regions are set such that portions of pairs of
mutually neighboring sub-regions overlap one another. However, the
present invention is not limited thus. Modes in which neighboring
pairs of sub-regions adjoin one another without overlapping are
also possible. In such a case, although the occurrence of hunting,
when zooming operations by a user that cross a boundary between
sub-regions many times are carried out, cannot be prevented, the
other effects of the digital camera 10 relating to the present embodiment
can be implemented.
Further still, the flow of photographic processing described for
the present embodiment (see FIG. 3) is an example. Obviously, it
is possible to suitably alter the processing within a scope that
does not deviate from the spirit of the present invention.
According to the present invention, in accordance with a photographic
magnification that is specified by a magnification setting section,
a first magnification is selected from a plurality of fixed magnification
values that have been set in advance, and is set at an optical zoom
function. A second magnification is set at an electronic zoom function
such that, when the optical zoom function is combined with the electronic
zoom function, an image is obtained at the photographic magnification
that has been specified. A settable range of magnifications that
can be provided by the optical zoom function is constituted by a
plurality of sub-regions that form portions of this range. For each
sub-region, a single magnification value included in that region
is set in advance as the aforementioned fixed magnification value.
Thus, power consumption during zooming can be reduced and, when
execution of photography is instructed thereafter, a time difference
between the time of instructing photography and the time of actual
photography can be made shorter.
Furthermore, when the plurality of sub-regions of the present invention
are structured such that portions of neighboring sub-regions overlap
one another, the occurrence of hunting, in which the fixed magnification
value of the optical zoom function is changed many times when zooming
operations in accordance with operation of a zoom operation section
cross a boundary between the sub-regions many times, can be prevented.
Moreover, a magnification operation section of the present invention
gives a first instruction and a second instruction for executing
photography, causing preparation for photography with the first
instruction and causing recording of image data to a recording medium
with the second instruction, and is structured such that, when the
photographic operation section causes preparation for photography,
the magnification setting section assigns the photographic magnification
that has been specified to the optical zoom function. Therefore,
the photographic magnification of the optical zoom function can
be set to a final magnification in a preparation step immediately
before the execution of photography. As a result, the time difference
between the time of instructing photography and the time of actual
photography can be made shorter. |