Digital Camera Patent AbstractA digital camera includes a first CPU 21 and a second CPU 22. The
first CPU 21 determines an operation of a release button 7 which
instructs to photograph an object, and a photographing request is
issued when the release button 7 is operated. On the other hand,
the second CPU 22 photographs the object by driving a CCD imager
1 when the photographing request is issued, and stores image data
of the object photographed into an SDRAM 4 in a compressed state.
The second CPU 22 further records into a memory card 4 compressed
image data stored in the SDRAM 4 predetermined amount by predetermined
amount, and determines whether or not the photographing request
is issued every time that a recording of the predetermined amount
is completed.
Digital Camera Patent ClaimsWhat is claimed is:
1. A digital camera, comprising: an instruction key for instructing
to photograph an object; a first CPU having a register which carries
out a first determination process for repeatedly determining whether
or not said instruction key is operated by checking the setting
value of said register, and an issuing process for issuing a photographing
request when a result of said first determination process is changed
from a negative result to an affirmative result; and a second CPU
which carries out a photographing process for photographing the
object, a storing process for storing into a buffer memory image
data obtained by said photographing process, a recording process
for recording the image data stored in said buffer memory by said
storing process into a recording medium every partial amount which
is smaller than a data amount of one screen, and a second determination
process for determining whether or not the photographing request
is issued by said issuing process every time that a recording of
the partial amount by said recording process is completed, wherein
said photographing process includes a process of photographing the
object when a result of said second determination process is affirmative.
2. A digital camera according to claim 1, further comprising a
selection key for selecting a specific photographing mode, wherein
said second CPU carries out said second determination process when
said specific photographing mode is selected.
3. A digital camera according to claim 1 or 2, wherein said second
CPU further carries out an acquiring process for acquiring an initiative
when the result of said second determination process is affirmative,
and an applying process for applying said initiative to said first
CPU after said storing process is completed, and said first CPU
carries out said first determination process and said issuing process
when said initiative is applied.
4. A digital camera according to any of claims 1 or 2, wherein
said storing process is a process of storing the image data into
said buffer memory in a compressed state.
5. A digital camera according to any of claims 1 or 2, wherein
said recording medium is detachable.
6. An image processing method of a digital camera provided with
a first CPU having a register and a second CPU, wherein said first
CPU carries out the steps of (a1) repeatedly determining whether
or not an instruction key for instructing to photograph an object
is operated by checking the setting value of said register, and
(b1) issuing a photographing request when a determination result
of said step (a1) is changed from a negative result to an affirmative
result, and said second CPU carries out the steps of (a2) photographing
the object, (b2) storing image data obtained by said step (a2) into
a buffer memory, (c2) recording into a recording medium the image
data stored in said buffer memory by said step (b2) every partial
amount which is smaller than a data amount of one screen, and (d2)
determining whether or not the photographing request is issued by
said step (b1) every time that a recording of the partial amount
is completed, wherein said step (a2) includes a step of photographing
the object when a determination result of said step (d2) is affirmative. Digital Camera Patent DescriptionTECHNICAL FIELD
The present invention relates to a digital camera and an image
processing method thereof. More specifically, the present invention
relates to a digital camera and an image processing method thereof
which store into an internal memory image data of an object photographed
in response to an operation of a shutter button, record in a recording
medium the image data in the internal memory predetermined amount
by predetermined amount, and determine whether or not a release
button is operated every time that a recording of the predetermined
amount is completed.
PRIOR ART
In recent years, a digital camera which photographs an object by
an image sensor such as a CCD imager, and etc, and records still
image data of the object photographed into a detachable recording
medium in a compressed state is praisefully used. However, there
is a digital camera which requires a processing time of several
seconds or so from photographing of the object to a completion of
recording the still image data so that it is not possible to operate
the release button during this processing time. In such the digital
camera, there is a problem to miss a perfect moment for a good picture.
It is noted that most of the processing time was spent not on a
generating process of the still image data or a compressing process
of generated still image data but on a recording process of the
compressed image data into the recording medium.
Accordingly, in a conventional digital camera which found a solution
to take a good picture in a perfect moment, following processings
are carried out when a specific photographing mode (immediate photographing
mode) is set. When the release button is operated, firstly, a generating
process of one frame of the still image data and a compressing process
of the generated still image data are performed, and the compressed
image data is temporarily stored in a SDRAM. A recording process
of the compressed image data stored in the SDRAM into the recording
medium is carried out predetermined amount by predetermined amount,
and it is determined whether or not the release button is operated
every time that the recording of the predetermined amount is completed.
When the release button is operated, newly generated compressed
image data is stored in the SDRAM by the generating process and
the compressing process described above.
A specific operation at this time is described by reference to
FIG. 4. A mode change switch 9, for changing a photographing mode
between a normal photographing mode and an immediate photographing
mode and a release button 7 are connected to a first CPU 8. The
first CPU 8 applies a corresponding state signal to a second CPU
10 when the mode change switch 9 or the release button 7 is operated.
If the release button 7 is operated in a state that the normal
photographing mode is selected, the second CPU 10 activates a CCD
imager 1. One frame of a raw image signal is output from the CCD
imager 1. The raw image signal is input into a signal processing
circuit 3 as raw image data via an AID converter 2. The signal processing
circuit 3 applies to the input raw image data processes such as
a color separation, a YUV conversion, and so on, and writes into
an image data storing area 4a of an SDRAM 4 through a memory control
circuit 5 still image data of a YUV format thus generated.
An image compressing circuit 6 reads out the still image data stored
in the image data storing area 4a through the memory control circuit
5, and compresses the read still image data according to a JPEG
format. The compressed image data is written into a compressed data
storing area 4b of the SDRAM 4 through the memory control circuit
5. When one frame of the compressed image data is obtained in the
compressed data storing area 4b, the second CPU 10 reads out the
compressed image data through the memory control circuit 5, and
records the read compressed image data into a detachable memory
card (semiconductor memory) 11.
On the other hand, if the release button 7 is depressed in a state
that the immediate photographing mode is selected, a process until
the compressed image data is written in the compressed data storing
area 4b (defined as a photographing process) is the same as above.
However, following processes are carried out in recording the compressed
image data into the memory card 11.
The CPU 10 issues an inquiry signal to the first CPU 8 at a time
that the one frame of the compressed image data is retained in the
compressed data storing area 4b. The first CPU 8 determines whether
or not the release button 7 is operated in response to the inquiry
signal, and sends back a determination result to the second CPU
10. When the determination result indicates "no operation",
the second CPU 10 reads out the compressed image data retained in
the compressed data storing area 4b by a predetermined amount smaller
than one frame of a data amount, and records in the memory card
11 the read compressed image data of the predetermined amount.
Upon completion of recording the predetermined amount, the CPU
10 outputs the inquiry signal once again to the first CPU 8. If
the determination result sent back in response thereto is "operated",
the second CPU 10 interrupts the recording process so as to carry
out a photographing process, and retains newly generated compressed
image data into the compressed data storing area 4b.
Thus, in the immediate photographing mode, it is determined whether
or not the release button 7 is operated every time that the recording
of the compressed image data of the predetermined amount is completed,
and the photographing process was carried out instead of the recording
process when the release button 7 is operated.
However, it is necessary that the inquiry signal is output from
the second CPU 10 toward the first CPU 8, and the determination
result is sent back from the first CPU 8 in order to determine whether
or not the release button 7 is operated. Two CPUs are concerned
regarding a generation of the inquiry signal and a sending back
of the determination result so that it takes time for an operation
determination of the release button 7. Consequently, this gave rise
to a problem that a total time for a recording process of the compressed
image data became prolonged if the determination result of the release
button 7 is often carried out, and a responsive characteristic of
the release button 7 deteriorates if the number of the determination
result of the release button 7 is decreased.
SUMMARY OF THE INVENTION
Therefore, it is a primary object of the present invention to provide
a digital camera capable of shortening a required time for a recording
process of image data, and improving a responsive characteristic
toward a photographing instruction.
It is another object of the present invention to provide an image
processing method of a digital camera capable of shortening a required
time for a recording process of the image data, and improving a
responsive characteristic toward a photographing instruction.
A digital camera according to the present invention, comprises:
an instruction key for instructing to photograph an object; a first
CPU which carries out a first determination process for determining
whether or not the instruction key is operated and an issuing process
which issues a photographing request when it is determined that
the instruction key is operated; and a second CPU which carries
out a photographing process for photographing the object when it
is determined that the photographing request is issued, a storing
process for storing into a buffer memory image data of the object
photographed, a recording process for recording the image data stored
in the buffer memory into a recording medium predetermined amount
by predetermined amount which is smaller than one screen of a data
amount, and a determination process for determining whether or not
the photographing request is issued every time that a recording
of the image data of the predetermined amount is completed.
The first CPU determines whether or not an instruction key for
instructing to photograph an object is operated and issues a photographing
request when the instruction key is operated. On the other hand,
the second CPU photographs the object when the photographing request
is issued, stores image data of the object photographed into a buffer
memory. Furthermore, the second CPU records into a recording medium
the image data stored in the buffer memory predetermined amount
by predetermined amount, and determines whether or not the photographing
request is issued every time that a recording of the predetermined
amount is completed.
Thus, the first CPU issues the photographing request by itself.
Therefore, the second CPU does not require more than to determine
whether or not the photographing request is issued so that a required
time for determining whether or not the instruction key is operated
is shortened. Consequently, it is possible to shorten a required
time for a recording process of the image data, and also improve
a responsive characteristic toward the photographing instruction.
In a preferred embodiment, the second CPU determines whether or
not the photographing request is issued according to an aforementioned
manner when a specific photographing mode is selected by the selection
key.
In another preferred embodiment, the second CPU acquires an initiative
when the photographing request is issued, and applies the initiative
to the first CPU after completing storing the image data into the
buffer memory. Thus, the acquiring the initiative is performed by
the second CPU. The first CPU carries out an operation determination
process of the instruction key and an issuing process of the photographing
request when the initiative is applied.
In still another preferred embodiment, the image data of the object
photographed is stored into the buffer memory in a compressed state.
In yet still another preferred embodiment, the recording medium
is detachable.
According to the present invention, an image processing method
of a digital camera provided with a first CPU and a second CPU,
wherein the first CPU determines whether or not an instruction key
for instructing to photograph an object is operated and issues a
photographing request when it is determined that the instruction
key is operated, and the second CPU photographs the object when
it is determined that the photographing request is issued, stores
image data of the object photographed into a buffer memory, records
into a recording medium the image data stored in the buffer memory
predetermined amount by predetermined amount which is smaller than
one screen of a data amount, and determines whether or not the photographing
request is issued every time that a recording of the image data
of the predetermined amount is completed.
Since the first CPU 21 issues the photographing request by itself,
and the second CPU does not require more than to determine whether
or not the photographing request is issued, so that a required time
for determining whether or not the instruction key is operated is
shortened. As a consequence, it is possible to shorten a required
time for the recording process of the image data, and it is also
possible to improve a responsive characteristic toward the photographing
instruction.
The above described objects and other objects, features, aspects
and advantages of the present invention will become more apparent
from the following detailed description of the present invention
when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram showing a configuration of one embodiment
of the present invention;
FIG. 2 is a flowchart showing one portion of an operation of a
first CPU;
FIG. 3 is a flowchart showing one portion of an operation of a
second CPU; and
FIG. 4 is a block diagram showing a configuration of a prior art.
BEST FORM FOR PRACTICING THE INVENTION
By reference to FIG. 1, a digital camera in this embodiment is
the same as a prior art shown in FIG. 4 except that a first CPU
21 processes a flowchart shown in FIG. 2 and a second CPU 22 processes
a flowchart shown in FIG. 3 so that a portion of duplicated descriptions
common to the prior art is omitted. It is noted that FIG. 3 shows
a process of the second CPU 22 when an immediate photographing mode
is selected.
Firstly, by reference to FIG. 2, a process of the first CPU 21
is described. In a step S1, it is determined whether or not an operation
of a release button 7 or a mode change switch 9 is operated by reference
to a register 21a of one bit which retains an operating state of
the release button 7 and a register 22b of two bits which retains
a changing state of the mode change switch 9.
While a setting value of the register 21a indicates "0"
if the release button 7 is turned off, the setting value of the
register 21a is renewed from "0" to "1" if the
release button 7 is turned on. In addition, the setting value of
the register 21b is renewed from "00" to "01"
or "11" when the photographing mode is changed, and restored
to "00" when a changing of the photographing mode is notified
to the second CPU 22. "01" is a value set when a normal
photographing mode is changed to an immediate photographing mode,
and "11" is a value set when changed to the normal photographing
mode from the immediate photographing mode.
Due to this, it is determined that the key is operated in the step
S1 when the setting value of the register 21a shows "1"
or the setting value of the register 21b shows "01" or
In a succeeding step S2, it is determined whether or not an initiative
is applied from the second CPU 22. Giving and losing the initiative
is carried out by the first CPU 21. More specifically, the initiative
is applied to the first CPU 21 in a step S22 described later, and
the initiative is lost from the first CPU 21 in a step S31. Accordingly,
it is determined whether or not the initiative is present in a step
S2. When the initiative is applied, a content of the key operation
is determined in the step S3 and in a step S6. The determination
is carried out based on the setting values in the register 21a and
21b.
When the register 21b shows "00" and the register 21a
shows "1", the process proceeds from the step S3 to a
step S4 on the assumption that the release button 7 is depressed.
In the step S4, it is notified to the second CPU 22 that the release
button 7 is operated. That is, a photographing request is output
to the second CPU 22. The register 21a is reset in a step S5, and
the process returns to the step S1 upon completion of the process
in the step S5.
When the register 21a shows "0" and the register 21b
shows "11", the process proceeds from the step S6 to a
step S7 on the assumption that the normal photographing mode is
selected by the mode change switch 9 in a state that the immediate
photographing mode is selected. In the step S7, the process inquires
of the second CPU 22 a state of a flag F owned by the second CPU
22. The flag F is validated in the immediate photographing mode,
shows "1" when the compressed image data is stored in
the compressed data storing area 4b, and shows "0" when
the compressed data storing area 4b is vacant.
A state of the flag F is determined based on a state signal sent
back from the second CPU 22 in a step S8. Herein, if the flag F
is "1", the process directly returns to the step S1 on
the assumption that the compressed image data is remained in the
compressed data storing area 4b and a photographing mode is not
to be changed. Therefore, the mode changing operation this time
is invalidated. On the other hand, if the flag F is "0",
it is notified to the second CPU 22 in a step S9 that the normal
photographing mode is selected. That is, a changing request to the
normal photographing mode is output to the second CPU 22. In a succeeding
step S10, the register 21b is reset, and the process returns to
the step S2 upon completion of the process in the step S10.
When the register 21a shows "0" and the register 21b
shows "01", the process proceeds from the step S6 to a
step S11 on the assumption that the immediate photographing mode
is selected by the mode change switch 9 in a state that the normal
photographing mode is selected. It is notified to the second CPU
22 that the immediate photographing mode is selected in the step
S11. That is, a changing request to the immediate photographing
mode is output to the second CPU 22. In a succeeding step S12, the
register 21b is reset, and the process returns to the step S1 upon
completion of the process in the step S12.
Next, by reference to FIG. 3, a description is made with regard
to a process of the second CPU 22 when the immediate photographing
mode is selected. The process starts in response to the step S11
process shown in FIG. 11. Firstly, the process sets the flag F to
"0" in a step S21, and applies the initiative to the second
CPU 22 in a step S22. The initiative moves from the second CPU 22
to the first CPU 21.
It is determined whether or not there is an inquiry from the first
CPU 21 in a step S23. If there is the inquiry, the state signal
showing a state of the flag F is sent back to the first CPU 21 in
a step S24, and the process returns to the step S22 later. When
there is no inquiry from the first CPU 21, YES is determined in
the step S24, and a state of the flag F is determined in a step
S26. Then, when the flag F shows "0", the process directly
returns to the step S22 on the assumption that the compressed data
storing area 4b is vacant.
The process proceeds to a step S25 when there is no inquiry from
the first CPU 21 so as to determine whether or not any notification
(photographing request or changing request) is applied from the
first CPU 21. When the notification is applied, the initiative is
obtained in a step S31, and a content of the notification is determined
in a step S32. If the content of the notification is a request to
change from the immediate photographing mode to the normal photographing
mode, NO is determined in the step S32, and the process shown in
FIG. 3 is terminated so as to start a process of the normal photographing
mode not shown.
On the other hand, if the content of the notification is a photographing
request, YES is determined in the step S32, and the photographing
process is carried out. Firstly, a CCD imager 1 is activated in
a step S33, and one frame of photographing is performed. Image data
of an object photographed is stored in an image data storing area
4a of the SDRAM 4. Subsequently, an image compression circuit 6
is activated in a step S34 so as to compress the image data and
store the compressed image data into the compressed data storing
area 4b. The image data stored in the image data storing area 4a
is read out by the memory control circuit 5, and subjected to a
JPEG compression by the image compression circuit 6. The compressed
image data obtained by the JPEG compression is stored into the compressed
data storing area 4b of the SDRAM 4 by the memory control circuit
5. Upon completion of the process in the step S34, the process returns
to the step S22 after setting the flag F to "1" in a step
S35.
When the notification is not applied from the first CPU 21, the
process proceeds from the steps S25 to the step S26 so as to determine
a state of the flag F. When the flag F shows "0", the
process directly returns to the step S23 on the assumption that
the compressed data storing area 4b is vacant. However, when the
flag F shows "1", the process proceeds to a step S27 so
as to carry out a recording process. In the step S27, only a predetermined
amount of the compressed image data stored in the compressed data
storing area 4b is recorded in the memory card 11. While a data
amount of one frame of the compressed image data is several M bytes,
the data amount (predetermined amount) recorded in the memory card
11 in a single recording process is some tens of K bytes. That is,
the predetermined amount is smaller than the amount of one frame
of the data.
Upon completion of the recording process of the predetermined amount,
it is determined whether or not the recording of all the compressed
image data stored in the compressed data storing area 4b is completed
in a step S28. Then, if there is image data yet to be recorded,
the process directly returns to the step S23. However, if there
is no image data yet to be recorded, the process returns to the
step S23 after setting the flag F to "0" in a step S29.
As understood from the above descriptions, the first CPU 21 determines
an operation of the release button 7 which instructs to photograph
an object, and issues the photographing request when the release
button 7 is operated. On the other hand, the second CPU 22 photographs
the object by driving the CCD imager 1 when the photographing request
is issued, and stores the image data of the object photographed
into the SDRAM (buffer memory) 4 in a compressed state. Furthermore,
the second CPU 22 records the compressed image data stored in the
SDRAM 4 in the memory card 4 predetermined amount by predetermined
amount, and determines whether or not the photographing request
is issued every time that the recording of the predetermined amount
is completed. It is noted that the predetermined amount is smaller
than the data amount of one frame of (one screen of) compressed
image data.
Thus, the first CPU 21 issues the photographing request by itself,
and the second CPU 22 does not require more than to determine whether
or not the photographing request is issued, so that a required time
for determining whether or not the release button 7 is operated
is shortened. As a consequence, it is possible to shorten a required
time for the recording process of the compressed image data, and
it is also possible to improve a responsive characteristic toward
the operation of the release button 7.
It is noted that in this embodiment, although the YUV conversion
process of the raw image data and the compressing process of the
image data in the YUV format are performed in a state that the initiative
is obtained, it may be possible that a process until the storing
process of the image data in the YUV format into the SDRAM is carried
out in a state that the initiative is obtained and the compressing
process of the image data and the recording process of the compressed
image data are carried out predetermined amount by predetermined
amount after the initiative is released. Furthermore, it may be
also possible that the raw image data is stored in the SDRAM in
a state that the initiative is obtained, and the YUV conversion
process, the compressing process, and the recording process are
carried out predetermined amount by predetermined amount after the
initiative is released.
Furthermore, in this embodiment, a semiconductor memory is used
as a recording medium. However, a disk recording medium such as
a magnetooptical disk, a hard disk, and so on may be used in stead
thereof. In addition, although a CCD-type image sensor is used in
this embodiment, a CMOS-type image sensor may be used instead thereof.
Although the present invention has been described and illustrated
in detail, it is clearly understood that the same is by way of illustration
and example only and is not to be taken by way of limitation, the
spirit and scope of the present invention being limited only by
the terms of the appended claims. |