Digital Camera Patent AbstractA digital camera 10 includes a systems control section 20. When
the systems control section 20 receives any of operation signals
from a key operation section 18, the systems control section 20
measures the passage of time with a timer 22, and continues the
time measurement for a specified period of time until any of the
operation signals is supplied. In an imaging mode, the system controls
section 20 generates an oscillation frequency higher than a normal
oscillation frequency with a signal generation circuit 260 in response
to a button depressing operation of a release shutter button 180,
and generates the normal oscillation frequency upon receipt of any
one of the operation signals in a specified period of time. The
system controls section 20 continues monitoring the operation signals
and generates an oscillation frequency lower than the normal frequency
to thereby control to lower the power consumption depending on the
result of the measurement of the passage of the specified period
of time by the timer 22.
Digital Camera Patent ClaimsWhat is claimed is:
1. A digital camera in which the timing to take in incident light
from a field is made to correspond to an operation of a shutter
button by an operator in order to convert the incident light into
an electrical signal, the electrical signal is output as an imaging
signal, and image data obtained by digitizing the imaging signal
are rendered a signal processing, the digital camera comprising:
an operating device that operates the camera including the shutter
button; an automatic exposure (AE) drive circuit; a charge coupled
device (CCD) drive circuit; a signal processing section comprising
a clock generating device that generates a clock signal having one
of a plurality of oscillation frequencies each corresponding to
an operation of the operating device, wherein the signal processing
section also supplies various parameters found by the signal processing
section; a time measuring device that measures time depending on
the operation resulting from the operator operating the operating
device; and a systems control device that determines an operational
state of the camera based on whether or not operation signals that
indicate operations of the operating device are present and that
controls the clock generating device and the power supply of the
camera, the systems control device using the various parameters
supplied by the signal processing section to generate control signals
that are supplied to and operate the AE drive circuit and the CCD
drive circuit based on the clock signal, wherein the signal processing
section further comprises an evaluation value calculation section
that calculates the various parameters supplied to the systems control
device based on image data supplied to the signal processing section,
wherein the systems control device performs an actual imaging control
to generate, in an imaging mode that includes a sequence to output,
convert and record imaging signals as image data and in response
to a depressing operation of the shutter button, the clock signal
having an oscillation frequency higher than a normal oscillation
frequency from among the plurality of oscillation frequencies generated
by the clock generating device, a normal control to generate, in
an imaging preparation mode, the clock signal having the normal
oscillation frequency in a period after the actual imaging control
or in a period starting from an initial power supply until a predetermined
amount of time has passed, and an energy saving control to generate
the clock signal having a frequency lower than the normal oscillation
frequency while continuing monitoring the operation signals upon
passage of the predetermined amount of time.
2. A digital camera according to claim 1, wherein the operating
device further includes a power supply selection device that selects
a power supply or a power shut-off to the apparatus, and an operational
mode selection device that selects operation modes that represent
general terms of processing procedures performed in association
of operations that operate the apparatus.
3. A digital camera according to any one of claim 1 or claim 2,
wherein the shutter button has only a fully depressing function
to initiate operation of an imaging system.
4. A digital camera according to claim 1, wherein the systems control
device monitors only an operation signal from the power supply selection
device among the operation signals in the energy saving control.
5. A digital camera according to claim 1, wherein: during the imaging
preparation mode, the systems control device supplies power to an
imaging system and to monitor the operation signals; and during
the energy saving control, the systems control device supplies power
only to monitor the operation signals.
6. A digital camera according to claim 1, wherein the evaluation
value calculation section calculates a diaphragm value/shutter speed,
a white balance adjustment value and a gray scale correction value. Digital Camera Patent DescriptionBACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital camera device, whose
ideal application is a digital camera with a pan focus function
or a toy digital camera.
2. Description of Related Art
Digital cameras are devices that convert incident lights into electrical
signals and record the image data obtained from the conversion.
These cameras are known to consume large amounts of power in order
to satisfy the demand for high-speed drive and to have an image
display function. In addition, it is generally considered desirable
for these cameras to be compact and lightweight so that they can
be portable. Consequently, the digital cameras use high-performance
batteries and various ingenious ideas are employed to extend their
operational time.
In a conventional digital still camera device, the device's operational
state is determined with an operational state determination device
based upon the status of a mode selection device that selects the
operational mode, the status of a power source switch device and
the status of a shutter switch device; a continuous operational
time in the operational mode as determined is measured with a measuring
device; and when it is determined that the predetermined amount
of time for each operational state has been exceeded a power saving
device turns off power to every part of the device except a control
system and the device goes into a power saving mode and thereby
manages to save power in every situation. Furthermore, the power
is turned on in appropriate operational states for a faster shooting
startup.
In supplying power adequately according to the operational state,
a clock in the control system to which power is supplied is at a
frequency lower than its normal frequency in the energy saving mode.
When a preliminary imaging is done by half depressing the release
shutter button in the energy saving mode followed by an actual imaging,
the timing to photograph the subject is sometimes missed.
SUMMARY OF THE INVENTION
The present invention solves such a shortcoming of the prior art
described above, and provides a digital camera device that would
not miss the timing to photograph the subject while minimizing the
power consumption.
In accordance with an embodiment of the present invention, there
is provided a digital camera in which the timing to take in incident
light from a field is made to correspond to an operation of a shutter
button by an operator in order to convert the incident light into
an electrical signal, the electrical signal is output as an imaging
signal, and image data obtained by digitizing the imaging signal
are rendered a signal processing, the digital camera comprising:
an operating device that operates the camera including the shutter
button; a clock generating device that generates a plurality of
oscillation frequencies each corresponding to an operation of the
operating device; a time measuring device that measures time depending
on the operation resulting from the operator operating the operating
device; and a systems control device that determines an operational
state of the camera based on whether or not operation signals that
indicate operations of the operating device are present and that
controls the clock generating device and the power supply of the
camera, accordingly, wherein the systems control device performs
a control to generate, in an imaging mode that includes a sequence
to output imaging signals and in response to a depressing operation
of the shutter button, an oscillation frequency higher than a normal
oscillation frequency from among the plurality of oscillation frequencies
generated by the clock generating device, a control to generate
the normal oscillation frequency within a predetermined amount of
time, and a control to generate a frequency lower than the normal
oscillation frequency while continuing monitoring the operation
signals depending on the result of measuring the passage of a predetermined
amount of time with the time measuring device.
The digital camera device according to the present invention is
operated through: receiving in the systems control device an operation
signal from the operating device; measuring the passage of a predetermined
amount of time until the operation signal is supplied while measuring
time with the time measuring device; controlling the clock generating
device to generate an oscillation frequency higher than normal in
response to the pressing operation of the shutter button in the
imaging mode; supplying the oscillation frequency generated to the
systems control device; performing a control to generate a normal
oscillation frequency within the predetermined amount of time; continuing
to monitor the operation signal depending on the result of measuring
the passage of predetermined amount of time with the time measuring
device; and at the same time controlling to generate a frequency
lower than the normal oscillation frequency and reducing the power
supply. As a result, the digital camera device according to the
present invention precisely images an imaging scene desired by the
operator and controls the power supply, while increasing the operation
speed of the camera according to the pressing operation of the shutter
button.
Other features and advantages of the invention will be apparent
from the following detailed description, taken in conjunction with
the accompanying drawings that illustrate, by way of example, various
features of embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically shows a block diagram of a structure of a
camera in which a digital camera apparatus according to an embodiment
of the present invention is applied.
FIG. 2 shows a table showing the settings of the key operation
section and the relationship between various camera operations and
modes.
PREFERRED EMBODIMENTS OF THE INVENTION
Next, a digital camera device in accordance with an embodiment
of the present invention will be described in detail with references
to the accompanying drawings.
In the present embodiment, the digital camera device is applied
to a toy type digital camera 10 (hereinafter called the "digital
camera 10"). Parts that are not directly related to the present
invention are omitted from drawings as well as their description.
Numbers assigned to various signals correspond to the numbers assigned
to connection lines on which the various signals appear.
The digital camera 10 includes an optical lens system 12, a diaphragm
mechanism 14, an imaging section 16, a key operation section 18,
a systems control section 20, a timer 22, a preprocessing section
24, a signal processing section 26, an AE (automatic exposure) drive
circuit 28, a timing signal generating (TG: timing signal generator)
section 30, a CCD (charge coupled device) drive circuit 32, a storage
section 34 and an external IF (interface) circuit 36.
The optical lens system 12 is structured, for example, by combining
a plurality of optical lenses and designed so that an incoming light
flux forms an image by focusing on the imaging section 16 via an
iris comprising the diaphragm mechanism 14. The optical lens system
12 can be configured to pan focus, whereby it fixes its focus in
a broad range on everything from a subject to the background, although
this function is omitted from the drawings. Additionally, the optical
lens system 12 may include an AF (auto focus) adjustment mechanism,
which finds the distance between the subject and the digital camera
10 during a preliminary imaging before an actual imaging and adjusts
the focus depending on the distance, and an AE adjustment mechanism,
which adjusts the amount of incident light. These mechanisms respond
to a drive signal supplied from a drive circuit described later.
The diaphragm mechanism 14 rotates a ring section depending on
the drive signal provided from a diaphragm drive circuit, although
this detail is omitted from the drawings. In the ring section, blades
partially overlap each other to form an iris in a circular shape
that allows light beams to enter. The diaphragm mechanism 14 changes
the aperture of the iris in this way. A mechanical shutter (omitted
from drawings) as a lens shutter may be assembled into the diaphragm
mechanism 14.
The imaging section 16 includes an optical low pass filter 16a,
a color filter 16b and solid imaging elements 16c. The optical low
pass filter 16a is a filter to render a spatial frequency of an
incident light at or below the Nyquist frequency. The color filter
16b is a filter in which its color filter segments comprising the
three primary colors RGB are laid out in predetermined positions
in a one to one relationship with each imaging element of the solid
imaging elements 16c. Consequently, the color filter 16b is dependent
on the layout of imaging elements of the solid imaging elements
16c. If the solid imaging elements 16c are in a staggered pixel
layout, i.e., a honeycomb layout, a G in the square and RB in the
fully checkered pattern, for example, is used. The color filter
16b is not limited to the one with the three primary colors RGB
and may be one with color filter segments of complementary colors.
However, in this case a process to convert complementary colors
into primary colors will be added in a signal processing step to
be performed later.
The solid imaging elements 16c may be a charge coupled device (CCD)
type or a metal oxide semiconductor (MOS) type. In the present embodiment,
the CCD type is used, and the solid imaging elements 16c generate
a signal charge by photoelectrically converting an incident light
that has passed through the optical lens system 12 and the iris
of the diaphragm mechanism 14. Although omitted from drawings, the
imaging elements are arrayed with a pitch that is defined by the
distance between pixels in vertical and horizontal directions, in
which pixels of adjacent elements are half a pitch staggered from
each other in vertical and horizontal directions. A vertical transfer
register that transfers signal charges in the vertical direction
in accordance with this layout is formed to circumvent adjacent
elements and is therefore formed in a meandering or zigzag manner.
A horizontal transfer register is formed in a direction orthogonal
to the vertical transfer register. The horizontal transfer register
transfers the signal charge supplied towards an output amplifier.
The output amplifier converts the signal charge (Q) into voltage
(V) and outputs it. The solid imaging elements 16c, in response
to the drive signal supplied from a CCD drive circuit to be described
later, actually become exposed to the incident light, transfer the
signal charge and reset elements. The imaging section 16 outputs
an imaging signal 16d to the preprocessing section 24.
The key operation section 18 includes a release shutter button
180, a mode selection switch 182 and a power source switch 184.
The release shutter button 180 supplies a timing signal 18a, which
indicates what the imaging timing is, to the systems control section
20. In the toy type digital camera according to the present embodiment,
the release shutter button 180 has only a single stroke (full depression).
Consequently, in the release shutter button 180 in the toy type
digital camera, a half depression for preliminary imaging (S1) and
a full depression (S2) for actual imaging take place at the same
time. The status of the release shutter button 180, i.e., a state
in which the release shutter button 180 is not pressed or a state
in which the release shutter button 180 is pressed, is notified
to the systems control section 20 as the timing signal 18a depending
on the operation.
The mode selection switch 182 supplies to the systems control section
20 a mode signal 18b that indicates which mode has been selected
for the digital camera 10. The mode selection switch 182 has at
least an imaging mode. The mode selection switch 182 may also have
a reproduction mode. In the reproduction mode, the digital camera
10 reproduces the image data already recorded. However, in the digital
camera 10, which is a toy type digital camera according to the present
embodiment, there is no liquid crystal display section installed
on the camera itself. It is known that in digital cameras the liquid
crystal display section consumes an extremely large amount of power.
In the reproduction mode, the image data are output to an external
monitor (omitted from drawings) to be displayed.
The power source switch 184 supplies to the systems control section
20 a selection signal 18c that indicates whether to supply or cut
off power from a battery, omitted from drawings, to the digital
camera 10.
The systems control section 20 is a microcomputer or a CPU (central
processing unit) that controls the general purpose parts of the
entire camera and the parts that perform digital processing. The
systems control section 20 receives as trigger signals the timing
signal 18a, the mode signal 18b and the selection signal 18c supplied
from the key operation section 18; and taking into account the status
of these trigger signals received, the systems control section 20
supplies to the timer 22 a time measure start signal 20a when the
operation section 18 is operated.
In addition to controlling the preprocessing section 24, the signal
processing section 26, the AE drive circuit 28 and the CCD drive
circuit 32, the systems control section 20 also controls the storage
section 34 and the external IF circuit 36, although the control
over the last two by the systems control section 20 is omitted from
drawings. When imaging, in response to having the release shutter
button 180 fully depressed in the imaging mode, the systems control
section 20 supplies a control signal 20b to the signal processing
section 26. When this happens, the control signal 20b is supplied
as a signal to instruct a signal generating circuit 260 within the
signal processing section 26 to supply a frequency higher (an integral
multiple of a reference clock) than the normal oscillation frequency
from among a plurality of clock signals. In the imaging mode, the
systems control section 20 does not execute any control over the
external IF circuit 36.
A clock signal 26a supplied from the signal generating circuit
260 is supplied to the systems control section 20. In addition,
information 26b regarding various parameters found by the signal
processing section 26 is also supplied to the systems control section
20. The systems control section 20 supplies control signals 20c
and 20d, which correspond to various parameters, to the AE drive
circuit 28 and the CCD drive circuit 32, respectively, to cause
certain operations to take place based upon the clock signal 26a.
Furthermore, the systems control section 20 supplies a control signal
20e to the preprocessing section 24 in order to execute a gain adjustment
of the imaging signal.
Moreover, the systems control section 20 reduces the oscillation
frequency of the clock signal 26a in a shoot preparation mode or
an energy saving mode, both described later, while also controlling
to limit the power supply destinations depending on the mode. In
the shoot preparation mode, the systems control section 20 supplies
power to circuits related to imaging and performs key scanning,
i.e., checks whether any key operations have been performed, while
monitoring the power supply. The systems control section 20 performs
this monitoring in the energy saving mode also but only performs
key scanning and turns off the power supply to other circuits.
The timer 22 has a function to measure the passage of time in which
no operation takes place continuously, such time being predetermined
for each mode. The control signal 20a supplied from the systems
control section 20 to the timer 22 is used as a trigger signal to
reset the timer and start measuring time when there is a key operation
of some sort by an operator at the key operation section 18. The
timer 22 can be set for each operational mode, and when the set
time has passed it outputs a no operation sensor signal 22a that
informs the systems control section 20 that the set time has passed.
Although omitted from drawings, the preprocessing section 24 includes
a correlated double sampling (CDS) circuit, an automatic gain control
(AGC) amplifier and an A/D converter (ADC: analog to digital converter)
section. Upon receiving the control signal 20e from the systems
control section 20, the preprocessing section 24 operates according
to various timing signals (omitted from drawings) supplied from
the timing signal generating section 30.
The correlated double sampling circuit reduces low frequency noise
components contained in the imaging signal 16d supplied. The noise-reduced
signal is waveform-shaped by undergoing amplification on the AGC
amplifier according to the control signal 20e. The A/D converter
section converts an analog signal supplied into a digital signal
24a and outputs it to the signal processing section 26.
The signal processing section 26 is a section that processes image
signals and comprises an RISC (reduced instruction set computer)
chip. Inside the chip are a memory, a gamma correction circuit,
an evaluation value calculation section, a pixel interpolation processing
circuit, a color difference matrix processing circuit and a compression/expansion
processing circuit, all omitted from the drawings, in addition to
the signal generating (SG) circuit 260.
The control signal 20b is supplied from the systems control section
20 to the signal processing section 26, and the signal generating
circuit 260 operates in response to the control signal 20b. The
signal generating (SG) circuit 260 has a PLL (phase locked loop)
circuit that can generate a plurality of frequencies. The signal
generating circuit 260 uses the original source oscillation frequency
as the reference clock and multiplies it in integral multiples to
generate a plurality of types of the clock signal 26a. The signal
generating circuit 260 generates the reference clock used in the
energy saving mode, the normal oscillation frequency used in the
shoot preparation mode, and the frequency for actual imaging mode
that is higher than the normal oscillation frequency. The signal
generating section 260 can set the original source reference clock
at a high frequency and divide the frequency of the reference clock,
but this is not desirable in terms of power consumption since it
entails a constant generation of a high frequency reference clock.
The memory receives inputs of image data 24a that have been converted
into digital data, temporarily stores them, and outputs them as
image data to the gamma correction circuit. When reading repeatedly,
it is desirable to use a nonvolatile memory. The gamma correction
circuit includes a look up table for gamma correction, for example.
As one of the preprocessing procedures in image processing, the
gamma correction circuit uses the data on the look up table to perform
gamma correction on the image data supplied. The gamma correction
circuit supplies the gamma-corrected image data to both the evaluation
value calculation section and the pixel interpolation processing
circuit.
The evaluation value calculation section includes an operational
circuit to calculate a diaphragm value/shutter speed, white balance
(hereinafter called WB) adjustment value and gray scale correction
value. The evaluation value calculation section uses operational
processing in the operational circuit to calculate various appropriate
parameters based on the image data supplied. The results of the
calculation are supplied as a parameter 26b to the systems control
section 20.
The evaluation value calculation section does not have to be installed
inside the signal processing section 26 and can be installed in
the systems control section 20. In this case, the signal processing
section 26 supplies the gamma-corrected image data to the systems
control section 20.
The pixel interpolation processing circuit has a function to interpolatedly
generate and calculate pixel data and a function to make the pixel
data generated compatible with broadband. Due to the fact that the
imaging section 16 uses a single plate color filter 16b, colors
other than the colors of the actual color filter segments cannot
be obtained from the imaging elements. The pixel interpolation processing
circuit generates by interpolation the pixel data of colors that
cannot be obtained. Further, it uses the pixel data generated that
includes the colors originally obtained to achieve higher frequency,
i.e., to perform a broadband processing. The pixel interpolation
processing circuit supplies plain broadband image data to the color
difference matrix processing circuit.
When the solid imaging elements 16c in the imaging section 16 are
in a honeycomb type, the pixel interpolation processing circuit
uses the gamma-corrected image data to generate, through interpolation
processing, pixel data in three primary colors RGB in positions
where pixels actually exist (real pixels) and positions where pixels
do not exist (virtual pixels).
The color difference matrix processing circuit generates a brightness
data Y, and color data Cb and Cr from the image data. The image
data generated are supplied to the compression/expansion processing
circuit.
The compression/expansion processing circuit uses JPEG (Joint Photographic
Coding Experts Group) standard, for example, to render compression
processing on the image data (Y/C) supplied in the actual imaging
mode. The compression/expansion processing circuit sends to and
records on the storage section 34 image data 26c compressed after
the actual imaging, and outputs them on a monitor, omitted from
drawings, via the external IF circuit 36. The compression/expansion
processing section reads the image data 26c recorded on the storage
section 34 and expands them. The expansion processing is the reverse
of the compression processing. The expanded image data (Y/C) 26c
are supplied to the external IF circuit 36 and an image signal 36a
reproduced is displayed on the monitor.
In order to eliminate any discrepancies between the predetermined
target diaphragm value and the photometric value of the parameters
related to exposure, the AE drive circuit 28 supplies a drive signal
28a that in response to the control signal 20c causes the ring section
to rotate.
Based on the clock signal 26a supplied from the signal generating
circuit 260, the timing signal generating circuit 30 generates various
timing signals such as a horizontal synchronizing signal, a vertical
synchronizing signal, a field shift gate pulse, a horizontal transfer
signal and a vertical transfers signal. The timing signal generating
circuit 30 supplies a timing signal 300 generated to the CCD drive
circuit 32.
The CCD drive circuit 32 controls the exposure time, reads onto
a transmission line a signal charge generated through photoelectric
transfer and supplies a drive signal 32a to the imaging section
16 to have the signal charge transferred in vertical and horizontal
directions.
The storage section 34 uses a semiconductor memory as a recording
medium and records the image data 26c supplied. Optical disks and/or
magnetic optical disks can also be used as the memory medium.
The external IF circuit 36 has interface functions to output to
the outside the image data and/or digital data supplied and to read
data input from the outside. The external IF circuit 36 manifests
these functions in the reproduction mode in the present embodiment.
The external IF circuit 36 has interfaces based on PIO (program
input/output), UART (universal asynchronous receive-transceiver),
USB (Universal Serial Bus), IEEE1394 standard (The Institute of
Electrical and Electronics Engineers), for example.
PIO is an interface section that can change input and output through
programs. UART is a device used in serial interfaces. This device
has a function to convert a parallel signal supplied into a serial
signal or to convert a serial signal sent from a serial device into
a parallel signal. An IEEE1394 standard interface, for example,
supports data transfer of up to 400 Mbps.
Although the digital camera 10 according to the present embodiment
is described above as not having an image display section, a liquid
crystal display may be mounted. However, in this case the digital
camera 10 will be controlled in such a way that power supply is
turned off in the energy saving mode to minimize power consumption.
In a camera with the structure described above, the operation speed
can be increased by supplying in the imaging mode a higher than
normal clock frequency, so that the imaging scene can be imaged
without being missed.
Next, the operational mode of the digital camera 10 will be described
(see FIG. 2). The operational mode is determined by inputting into
the systems control section 20 the timing signal 18a, the mode signal
18b and the selection signal 18c, which indicate the operational
status of the release shutter button 180, the mode selection switch
182 and the power source switch 184, respectively, of the key operation
section 18. The systems control section 20 changes the mode depending
on the result of the determination. First, regardless of the status
of the release shutter button 180 and of the mode selection switch
182, if the power source switch 184 is off, the camera 10 goes into
a power off state.
Next, when the power source switch 184 is turned on and if the
mode selection switch 182 indicates reproduction (the reproduction
mode), the release shutter button 180 does not become involved in
any operations. In this case, regardless of whether the energy saving
mode is set, the systems control section 20 switches to the energy
saving mode after a predetermined amount of time has passed. The
energy saving mode in the reproduction mode is a mode to perform
key scanning, which monitors whether the signals 18a, 18b and/or
18c from the key operation section 18 have been supplied, and to
monitor power supply. If there is a liquid crystal display section,
omitted from the drawings, installed, the systems control section
20 in this mode controls to turn off the power supply to the display
system related to a display on the liquid crystal display section.
When the power source switch 184 is turned on and the mode selection
switch 182 indicates imaging (shooting mode), the systems control
section 20 performs an operational control according to the status
of the release shutter button 180 and to each of a plurality of
states (modes) having the following measured time. First, if the
release shutter button 180 has been fully depressed, the systems
control section 20 controls the signal generating circuit 260 to
generate a clock signal having a frequency higher than the normal
clock signal and immediately begins an imaging sequence. In the
imaging sequence, a preliminary imaging takes place as the shutter
is operated on the digital camera 10 and an exposure parameter is
generated; the AE drive and the CCD drive corresponding to the exposure
parameter generated take place and the imaging signal 16d is obtained
from the imaging section 16. After this, the imaging signal 16d
goes through the preprocessing section 24 and the signal processing
section 26 and is supplied to the storage section 34 as the image
data 26c to be recorded there. This is the series of procedures
that takes place.
The timer 22 begins to measure time when the imaging sequence ends
or immediately after the power is turned on. When the predetermined
amount of time has passed, the timer 22 outputs the no operation
sensor signal 22a to the systems control section 20 to indicate
that the time measuring has finished. During the predetermined amount
of time, the systems control section 20 determines the device to
be in the shoot preparation mode and controls in such a manner that
the oscillation frequency is one that is commonly and generally
used in cameras. In this mode, power is supplied to the imaging
system related to imaging, and the key scanning and the monitoring
of the power supply described earlier are controlled. If the liquid
crystal display section is installed, the systems control section
20 supplies power according to the user setting that has been set
beforehand.
When the release shutter button 180 is fully depressed in this
mode, the imaging sequence described above operates on a high-speed
clock signal, which allows an imaging scene to be shot precisely
without being missed. The systems control section 20 controls these
operations whose top priority is imaging and that take place starting
with the shoot preparation mode to when the imaging begins.
When the time measuring is completed and the no operation sensor
signal 22a is supplied to the systems control section 20, the systems
control section 20 controls to switch to the energy saving mode
within the shooting mode, as indicated by an arrow. The operation
to switch modes after a predetermined amount of time has passed
takes place when the energy saving mode is not the set mode. In
this energy saving mode, the power supply monitoring and key scanning
are utilized but power to other systems is turned off. At the same
time, the systems control section 20 controls to have the signal
generating circuit 260 output the reference clock, i.e. the lowest
frequency, for example. By restraining the power supply itself and
reducing the frequency, the power consumption in this mode can be
diminished significantly.
In contrast, if the energy saving mode is set to function within
the shooting mode, the imaging sequence begins when the release
shutter button 180 is fully depressed. However, when the digital
camera 10 is in the energy saving mode, the systems control section
20 allows the imaging sequence to take place after power supply
is resumed. The systems control section 20 controls to switch to
the energy saving mode as soon as the imaging sequence ends. By
operating in this manner, an imaging control with the greatest emphasis
on minimizing power consumption can be executed.
By controlling and causing the digital camera 10 to operate in
this way depending on whether the energy saving mode is set, the
systems control section 20 can cause the digital camera 10 to have
two contradictory functions of giving a priority to imaging scenes
and of restraining power consumption.
Although a pan focus camera has been described in the present embodiment,
needless to say the present invention's application is not limited
to such a camera and would allow a precise imaging while also reducing
power consumption in any camera in which a half depression of the
release shutter button 180 is possible and that at least has an
AE locking function when the shutter button 180 is half depressed.
With a structure as described above, the digital camera 10 is able
to have two contradictory functions of giving a priority to imaging
scenes and of restraining power consumption through the following:
the oscillation frequency, which is generated in the signal generating
circuit by taking into account the operation signal supplied when
an operator performs a key operation and the measurement of the
predetermined amount of time using a timer is controlled; the signal
of the oscillation frequency generated is supplied to the systems
control section 20 as the clock signal; and the camera is operated
based on whether the energy saving mode is set.
The digital camera device according to the present invention restrains
power consumption and achieves a long drive for the camera, while
at the same time capturing images without missing any imaging opportunities
by precisely imaging the imaging scene desired by the operator and
controlling the power supply, and these are achieved through the
following: it receives in the systems control device the operation
signal from the operating device; it measures the passage of the
predetermined amount of time until the operation signal is supplied
while measuring time with the time measuring device; it controls
the clock generating device to generate an oscillation frequency
higher than normal in response to the pressing operation of the
shutter button in the imaging mode; it supplies the oscillation
frequency generated to the systems control device; it controls to
generate a normal oscillation frequency within the predetermined
amount of time; it continues to monitor the operation signal depending
on the result of measuring the passage of predetermined amount of
time with the time measuring device, while at the same time controlling
to generate a frequency lower than the normal oscillation frequency
and reducing the power supply; and it increases the operation speed
of the camera according to the pressing operation of the shutter
button.
The embodiment above describes preview display, but index printing
in which a plurality of thumbnail images are printed can be processed
similarly. When an automatic index printing is selected, thumbnail
images that have not been index printed can be printed first.
In the embodiment described above, various circuits are constructed
in hardware. However, functions equivalent to the various circuits
can be constructed through software.
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