Digital Camera Patent Abstract
The invention provides a digital camera comprising a disk drive
device 1, control circuit 2, flash memory 7, flag processing circuit
8 and memory 9. Power can be supplied to the flag processing circuit
8 and the memory 9 at all times. The control circuit 2 reads image
management data from a disk, writes the read data to the flash memory
7, and thereafter gives a flag rewrite command to the flag processing
circuit 8. The circuit 8 changes a flag in the memory 9 to "1"
in response to the command, and changes the flag to "0"
when withdrawal of the disk from the drive device 1 is thereafter
detected. The control circuit 2 reads and writes the image management
data only when the power source of main body of the camera is turned
on, with the flag set to "0", whereby the power consumption
of the camera can be reduced. Digital Camera Patent Claims
What is claimed is:
1. A digital camera comprising an image pickup device and a disk
drive device adapted to record on a disk images photographed by
the image pickup device and image management data as to the images
as digital data, or to reproduce images and image management data
recorded on the disk, the digital camera being characterized in
that the camera comprises: memory means comprising a nonvolatile
memory for storing the image management data recorded on the disk,
information processing means for reading the image management data
from the disk as placed in the disk drive device and writing the
read image management data to the memory means when a power source
of main body of the camera is turned on, means for storing therein
a flag having a first value indicating a need to cause the information
processing means to read and write the image management data or
a second value indicating that there is no need to do so, said flag
storing means being a separate component from other storing means
of said camera, flag processing means for rewriting the flag in
response to an action of a user, said flag processing means being
a separate component from other processing means of said camera,
and power supply means for holding the flag storing means and the
flag processing means in operation at all times, the information
processing means comprising: means for checking whether the flag
stored in the flag storing means has the first value or the second
value when the camera body power source is turned on, and data processing
means for reading the image management data from the disk as placed
in the disk drive device and writing the read image management data
to the memory means when the flag has the first value.
2. A digital camera according to claim 1 wherein the flag processing
means comprises: means for detecting withdrawal of the disk from
the disk drive device, and flag rewrite means for changing the flag
value to the second value in response to a flag rewrite command
and changing the flag value to the first value when the disk is
drawn out to the disk drive device, the information processing means
comprising means for commanding the flag rewrite means to rewrite
the flag when the image management data has been read and written
by the data processing means.
3. A digital camera according to claim 1 wherein the information
processing means comprises first updating means for updating the
image management data on the disk in response to an action of the
user, and second updating means for updating the image management
data written to the memory means upon updating of the image management
data on the disk.
Digital Camera Patent Description
FIELD OF THE INVENTION
The present invention relates to digital cameras comprising a disk
drive device which is adapted to record on a disk images photographed
by an image pickup device such as a CCD (charge-coupled device)
and image management data as to the images as digital data, or to
reproduce the images and image management data recorded on the disk.
BACKGROUND OF THE INVENTION
Digital cameras are known in recent years which are equipped with
a disk drive device capable of recording the images photographed
by an image pickup device, such as a CCD, on an erasable optical
disk, hard disk or like disk as digital data, or reproducing the
images recorded on the disk.
Optical disks have a region for recording the images photographed
by a CCD, and a region for recording image management data as shown
in a signal recording format of FIG. 4. When the digital camera
equipped with a disk drive device, for example, for optical disks
is used for taking photographs, image data as to the image photographed
by the CCD is converted to digital data and then compressed according
to the JPEG (Joint Photographic Coding Experts Group) system or
MPEG (Moving Picture Coding Experts Group) system, and the compressed
image data obtained is recorded as an image file in the image recording
region of the optical disk. Image management data as to the image
file is recorded in the image management data recording region.
The image management data contains, for example, a file name indicating
the name of the image file, and position data indicating the position
where the image file is recorded.
With the digital camera of the type described, the image management
data recorded on the optical disk is read therefrom and written
to a RAM or like memory incorporated in the camera main body when
the user turns on the power source of the camera main body with
the disk set in the disk drive device, or when the user sets the
disk in the drive device with the power source turned on.
When the user thereafter performs a predetermined procedure for
reproducing the desired image file among a plurality of image files
recorded on the disk, the image file selected by the user is specified
with reference to the image management data written to the memory
as described above and reproduced from the disk.
Since the memory used in the conventional digital camera described
is a volatile memory, the image management data stored in the memory
disappears immediately when the power source of the camera main
body is switched off to discontinue the supply of power to the memory.
Accordingly, even in the case where the power source of the camera
main body which is on is switched off with the disk set in the drive
device, and the power supply is thereafter turned on without changing
the disk, it is necessary to move the pickup of the drive device
to the image management data recording region of the disk to read
the image management data again from the disk and write the read
data to the memory.
Thus, there is a need to read and write the image management data
every time the power source of the cameral main body is turned on
whether the disk is replaced or not, so that the conventional digital
camera has the problem of necessitating great power consumption.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a digital camera
which is reduced in power consumption.
The present invention provides a digital camera comprising an image
pickup device and a disk drive device adapted to record on a disk
images photographed by the image pickup device and image management
data as to the images as digital data, or to reproduce images and
image management data recorded on the disk. The digital camera is
characterized in that the camera comprises: memory means comprising
a nonvolatile memory for storing the image management data recorded
on the disk, information processing means for reading the image
management data from the disk as placed in the disk drive device
and writing the read image management data to the memory means when
a power source of main body of the camera is turned on, means for
storing therein a flag having a first value indicating a need to
cause the information processing means to read and write the image
management data or a second value indicating that there is no need
to do so, flag processing means for rewriting the flag in response
to an action of a user, and power supply means for holding the flag
storing means and the flag processing means in operation at all
times. The information processing means comprises: means for checking
whether the flag stored in the flag storing means has the first
value or the second value when the camera body power source is turned
on, and data processing means for reading the image management data
from the disk as placed in the disk drive device and writing the
read image management data to the memory means when the flag has
the first value.
With the digital camera of the present invention, the image pickup
device, disk drive device, memory means and the information processing
means are in operation with power supplied thereto while the power
source of the camera main body is on, and are held out of operation
with the power supplied discontinued when the power source is off.
On the other hand, the flag processing means is held in operation
at all times, always detecting the action or manipulation by the
user, if any, whether the camera main body power source is on or
off. The flag processing means rewrites the flag in the flag storing
means, for example, when the disk is drawn out of the drive device
by the user or when the user turns on the power source for the data
processing means to write image management data to the memory means
as will be described below. Since the flag storing means is held
in operation at all times, it is unlikely that the flag in the flag
storing means will be lost by turning on the power source of the
camera main body.
With the digital camera described above, a plurality of images
photographed by the image pickup device are recorded on the image
recording region of the disk, and image management data as to these
images is stored in the image management data recording region thereof.
Immediately when the user sets in the drive device the disk having
the images and image management data recorded thereon as described
above and turns on the power source of the camera main body, power
is supplied to the image pickup device, disk drive device, memory
means and information processing means. The checking means of the
information processing means checks whether the flag in the flag
storing means has the first value or second value.
When the flag is found to be of the first value by the checking
means, the image management data is read from the region recording
this data on the disk, and the read image management data is written
to the memory means. The camera is then made ready for photographing
and image reproduction.
If the flag is found to be of the second value by the checking
means, on the other hand, the camera is made ready for photographing
and reproduction without the reading and writing of the image management
data. Since the memory means comprises a nonvolatile memory, the
memory means has stored therein the image management data immediately
before the camera main body power source is switched from off-state
to on-state previously, and the image management data in the memory
means is in match with the image management data recorded on the
disk as set in the drive device.
With the digital camera of the present invention, the image management
data is read and written when the camera main body power source
in off state is turned on only in the case where the flag has the
first value, so that the camera is smaller in power consumption
than the conventional digital camera wherein the image management
data is read and written every time the camera main body power source
is turn on.
Stated more specifically, the flag processing means comprises:
means for detecting withdrawal of the disk from the disk drive device,
and flag rewrite means for changing the flag value to the second
value in response to a flag rewrite command and changing the flag
value to the first value when the disk is drawn out of the disk
drive device; and the information processing means comprises: means
for commanding the flag rewrite means to rewrite the flag when the
image management data has been read and written by the data processing
means.
When the camera main body power source which is off is turned on
by the user, with the disk set in the drive device, the flag is
checked as to whether the flag has the first value or second value
as stated above, and the image management data is read and written
in the case where the flag is of the first value. At this time,
a flag rewrite command is given to the flag rewrite means to change
the flag from the first value to the second value.
The user will turn on the camera main body power source after turning
off the power source with the disk set in the drive device, drawing
out the currently set disk from the drive device for replacement
and setting another disk in the drive device. At this time, the
flag is checked for the value. The flag is found to be of the first
value if the disk is drawn out while the power source is off. The
image management data is therefore read and written, and the camera
then becomes ready for photographing and reproduction.
On the other hand, the user will turn off the camera main body
power source with the disk set in the drive device and thereafter
turn on the power source without replacing the disk. At this time,
the flag is checked for the value. The flag is then changed from
the first value to the second value as stated above and is thereafter
held at the second value. Accordingly, the camera becomes ready
for photographing and reproduction without the reading and writing
of the image management data.
With the digital camera having the foregoing construction, the
image management data is read and written to a memory upon the power
source of the camera main body being turned on only in the case
where the disk has been replaced with the power source off.
Further stated more specifically, the information processing means
comprises first updating means for updating the image management
data on the disk in response to an action of the user, and second
updating means for updating the image management data written to
the memory means upon updating of the image management data on the
disk.
For example when the digital camera thus constructed is used for
photographing, the image photographed by the image pickup device
is recorded on the image recording region of the disk, and the image
management data in the region for recording this data is updated.
The image management data stored in the memory means is also updated.
Accordingly even in the case where the user turns off the power
source of the camera main body after photographing an image and
subsequently turns on the power source again without replacing the
disk, the image management data stored in the memory means is in
match with the image management data recorded on the disk, so that
the image management data need not be read or written when the power
source is turned on. This results in a further reduction in power
consumption.
With the digital camera of the present invention, the image management
data is read and written when the power source of the camera main
body is turned on only in the case where the flag has the first
value. The camera is therefore smaller in power consumption than
the conventional digital camera wherein the image management data
is read and written every time the power source of the camera main
body is turned on.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing the construction of a digital
camera of the invention;
FIG. 2 is a flow chart showing the procedure to be performed by
a control circuit of the invention for reading and writing image
management data;
FIG. 3 is a flow chart showing the flag rewriting procedure to
be performed by a microcomputer incorporated in a flag processing
circuit of the invention; and
FIG. 4 is a diagram showing a signal recording format of optical
disks.
DETAILED DESCRIPTION OF EMBODIMENT
An embodiment of the invention will be described below in detail
with reference to the drawings.
The digital camera of the present invention is adapted to record
on erasable optical disks the images, such as still pictures or
moving pictures, photographed by a CCD, and comprises a disk drive
device 1 for optical disks as shown in FIG. 1.
The disk drive device 1 is connected by a bus 10 to a control circuit
2, which has connected thereto a CCD 3, LCD (liquid-crystal display)
4, RAM 5 and image processing circuit 6 by the bus 10. These components,
i.e., drive device 1, control circuit 2, CCD 3, LCD 4, RAM 5 and
image processing circuit 6, each perform a predetermined operation
with power supplied thereto when the power source of the camera
main body is turned on, or cease the operation upon an interruption
of power supply when the camera main body power source is turned
off.
The user depresses a shutter button (not shown) with the camera
main body power source on, whereupon the data as to the image photographed
by the CCD 3 is fed to the image processing circuit 6 for conversion
to digital data, which is compressed according to the JPEG or MPEG
system or the like. The compressed image data obtained is recorded
as an image file in the image recording region of an optical disk
shown in FIG. 4. Image management data indicating the name of the
image file and the position of the file is recorded in the image
management data recording region of the disk.
Also connected by the bus 10 to the control circuit 2 is a flash
memory 7 for writing thereto the image management data recorded
on the disk as described above. Other known erasable nonvolatile
memory, such as EPROM or EEPROM, is usable in place of the flash
memory 7.
Power is supplied to the flash memory 7 when the camera body power
source is turned on, or the power supply to the memory 7 is discontinued
when the power source is turned off.
A flag processing circuit 8 having a microcomputer incorporated
therein is connected to the disk drive device 1, while a memory
9 is connected to the flag processing circuit 8. The flag processing
circuit 8 and the memory 9 are connected to the control circuit
2. Power can be supplied to the flag processing circuit 8 and the
memory 9 at all times whether the power source of the camera main
body is turned on or off.
The memory 9 is provided with a column to which is written a flag
having the value "0" indicating a need to read the image
management data from the optical disk or the value "1"
indicating that this is unnecessary.
The disk drive device 1 has incorporated therein a switch (not
shown) which is on when the optical disk is set in the device or
off when no disk is set therein.
The microcomputer of the flag processing circuit 8 recognizes the
on-state of the switch and feeds a set signal to the control circuit
2. When thereafter given the flag rewrite command to be described
below by the control circuit 2, the microcomputer changes the flag
in the memory 9 from "0" to "1".
Upon the switch changing from on-state to off-state, the microcomputer
of the flag processing circuit 8 detects this change and changes
the flag in the memory 9 from "1" to "0".
FIG. 2 shows the image management data reading and writing procedure
to be performed by the control circuit 2 of the invention.
When the power source of the camera main body is turned on, an
inquiry is made in step S1 as to whether a set signal has been received
from the flag processing circuit 8. If an optical disk is set in
the disk drive device 1, the inquiry is answered in the affirmative
with the set signal supplied from the circuit 8, followed by step
S2, whereas if not disk is set in the drive device 1, the inquiry
of step S1 is answered in the negative, followed by step S1 again
to repeat the same inquiry.
Step S2 inquires whether the flag written to the memory 9 is "0".
If the answer is affirmative, the sequence proceeds to step S3,
in which image management data is read from the optical disk, and
the read management data is written to the flash memory 7 in step
S4. Subsequently in step S5, the control circuit 2 gives a flag
rewrite command to the flag processing circuit 8, followed by step
S1 again.
When the flag in the memory 9 is found to be "1" and
step S2 is answered in the negative, step S6 follows to inquire
whether the shutter button has been depressed. If the answer is
negative, the sequence returns to step S1.
Upon the user depressing the shutter button for photographing,
step S6 is answered in the affirmative, followed by step S7 to write
compressed data as to the image taken by the CCD 3 and update the
image management data recorded on the disk.
Subsequently, the image management data in the flash memory 7 is
updated in step S8, an inquiry is made in step S9 as to whether
the power source is off, and the sequence returns to step S1 if
the answer is negative. On the other hand, the procedure is terminated
when the answer is affirmative.
According to the procedure described, the image management data
is read from the optical disk and written to the flash member 7
when the flag in the memory 9 is "0", while if the flag
in the memory 9 is "1", this operation is not performed,
and the camera is ready for photographing and reproduction.
FIG. 3 shows the flag rewriting procedure to be performed by the
microcomputer incorporated in the flag processing circuit 8.
A flag with "0" is written to the memory 9 first in step
S11, and an inquiry is then made in step S12 as to whether an optical
disk is set in the disk drive device 1 with reference to the on-off
state of the switch incorporated in the drive device 1. When the
answer is negative, step S12 follows again to repeat the same inquiry.
On the other hand, when the inquiry of step S12 is answered in
the affirmative, step S13 follows, starting to output a set signal
to the control circuit 2. An inquiry is thereafter made in step
S14 as to whether a flag rewrite command is given by the control
circuit 2. If the answer is negative, step S14 follows again to
repeat the same inquiry.
In the case where the flag rewrite command is given by the control
circuit 2 in step S5 shown in FIG. 2, an affirmative answer is obtained
in step S14 of FIG. 3, and the flag in the memory 9 is changed from
"0" to "1" in step S15.
Subsequently in step S16, an inquiry is made as to whether the
disk is drawn out of the drive device 1 with reference to the on-off
state of the switch incorporated in the drive device 1. When the
answer is negative, step S16 follows again to repeat the same inquiry.
When the inquiry of step S16 is answered in the affirmative with
the disk removed from the drive device 1, step S17 follows to cease
the set signal output to the control circuit 2, and the sequence
returns to step S11.
According to the procedure described, the flag in the memory 9
is changed from "0" to "1" when the image management
data recorded on the disk set in the drive device 1 is written to
the flash member 7. The switch is thereafter checked for the withdrawal
of the disk, and the flag is changed from "1" to "0"
upon the disk being drawn out of the drive device.
With the digital camera thus embodying the invention, image management
data is read and written to a memory upon the power source of the
camera main body being turned on in the case where the disk has
been replaced with the power source off, and image management data
is read and written upon replacement of the disk while the power
source is on.
With the digital camera of the present embodiment, the image management
data is read and written when the power source of the camera main
body is turned on only in the case where disk replacement is made
while the power source is off. The camera is therefore smaller in
power consumption than the convention digital camera wherein the
image management data is read and written every time the power source
of the camera main body is turned on. |