Digital Camera Patent AbstractA digital camera includes a CCD imager. In a successive picture-taking
mode, each time a subject is taken by the CCD imager, a corresponding
main image signal is compressed by a JPEG CODEC. The compressed
main image signals produced upon each picture taking are accumulated
in a SDRAM. A compression process of thumbnail image signals is
performed after completing successive picture taking by the CCD
imager. That is, each of the compressed main image signals secured
in the SDRAM is decompressed by the JPEG CODEC, a thumbnail image
signal is produced on the basis of a decompressed image signal so
that a produced thumbnail image signal is compressed by the JPEG
CODEC. When all the compressed thumbnail image signals are produced,
each of a compressed main image signal and compressed thumbnail
image signal is recorded onto a memory card.
Digital Camera Patent ClaimsWhat is claimed is:
1. A digital camera which records, in a coded state, a plurality
of frames of main image data and a plurality of frames of size-reduced
image data which are obtained by successive picture-taking operations
to a recording medium, comprising: a main image coder for coding
a single frame of main image data every time a single picture-taking
operation is carried out so as to create a single frame of coded
main image data which is reduced in a data amount prior to the taking
of the next successive picture; a main image writer for writing
the single frame of coded main image data to an internal memory
every time a single coding operation is carried out by said main
image coder; and a size-reduced image coder for coding the plurality
of frames of size-reduced image data after ending the successive
picture taking operations, wherein said main image coder adopts
a JPEG format as a coding format.
2. A digital camera according to claim 1, further comprising: a
size-reduced image creator for respectively creating the plurality
of frames of size-reduced image data based on a plurality of frames
of the coded main image data held by said internal memory after
ending the successive picture taking operations, wherein said size-reduced
image coder codes the plurality of frames of size-reduced image
data created by said size reduced image creator.
3. A digital camera according to claim 2, wherein said size-reduced
image creator includes a decoder to decode the plurality of frames
of coded main image data held by said internal memory so as to create
a plurality of frames of decoded main image data, and a thinner
to perform thinning out on the plurality of frames of decoded main
image data so as to create the plurality of frames of size-reduced
image data.
4. A digital camera according to claim 1, further comprising: a
size-reduced image creator for creating a single frame of size-reduced
image data every time the single picture-taking operation is carried
out; and a size-reduced image writer for writing the single frame
of size-reduced image data to said internal memory every time a
single creating operation is carried out by said size-reduced image
creator, wherein said size-reduced image coder codes the plurality
of frames of size-reduced image data held by said internal memory
after ending the successive picture taking operations.
5. A digital camera which records, in a coded state, a plurality
of frames of main image data and a plurality of frames of size-reduced
image data which are obtained by successive picture-taking operations
to a recording medium, comprising: a main image coder for coding
a single frame of main image data every time a single picture-taking
operation is carried out so as to create a single frame of coded
main image data which is reduced in a data amount prior to the taking
of the next successive picture; a main image writer for writing
the single frame of coded main image data to an internal memory
every time a single coding operation is carried out by said main
image coder; and a size-reduced image coder for coding the plurality
of frames of size-reduced image data after ending the successive
picture taking operations, wherein both of the main image data to
be coded by said main image coder and the size-reduced image data
to be coded by said size-reduced image coder are digital image data. Digital Camera Patent DescriptionBACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to digital cameras and, more particularly,
to a digital camera which records, to a recording medium, in a compressed
state of main and size-reduced image signals corresponding to respective
images of a subject taken successively.
2. Description of the Prior Art
According to DCF (Design rule for Camera File system), there is
a need of producing thumbnail image signals in addition to main
image signals so that both the image signals are recorded in a compressed
state to a recording medium. Consequently, in the conventional digital
camera, the main image signal is first compressed and then the thumbnail
image signal produced from the main image signal is compressed so
that both compressed signals are recorded to a recording medium.
Meanwhile, during successive picture taking, totally-twice compression
processes of main and thumbnail image signals must be waited for
taking the next picture. After completing the last-time picture
taking, all the compressed signals are recorded to the recording
medium.
However, during successive picture taking, the picture-taking interval
increases if the next picture taking is commenced after twice of
compression processes have been done. It would be possible to shorten
the picture-taking interval by compressing both the main and thumbnail
image signals after completing successive picture taking. This however
results in increase in the capacity of an internal memory.
SUMMARY OF THE INVENTION
Therefore, it is a primary object of the present invention to provide
a digital camera capable of reducing the picture-taking interval
during successive shooting and suppresses the capacity of an internal
memory.
According to the present invention, a digital camera for recording,
in a compression state, a plurality of main image signals and a
plurality of size-reduced image signals that correspond to a plurality
of successively taken subject images to a recording medium, comprises:
a main image compressor for compressing one of the main image signals
each time picture taking is made once; and a size-reduced image
compressor for compressing the plurality of size-reduced image signals
after ending successive taking of pictures.
When a subject is successively taken of pictures, a plurality of
main image signals and a plurality of size-reduced image signals
are produced corresponding to a plurality of subject images successively
taken. These image signals thus produced are recorded in a compressed
state to a recording medium. Here, compression of the main signals
is made by a main image compressor while compression of the size-reduced
image signals is by a size-reduced image compressor. However, the
main image compressor compresses one main image signal each time
picture taking is made once, and the size-reduced image compressor
compresses a plurality of size-reduced image signals after ending
the successive picture taking.
Because a plurality of size-reduced image signals are compressed
after ending successive picture taking in this manner, it is possible
to shorten the picture-taking interval. Also, because the main image
signal is compressed each time picture taking is made once, it is
possible to suppress the capacity of an internal memory.
In one embodiment of the invention, a plurality of compressed main
image signals produced by the main image compressor are temporarily
held by a memory. When the successive picture taking is ended, a
size-reduced image producer produces the plurality of size-reduced
image signals on the basis of the plurality of compressed main image
signals held by the memory after ending the successive taking of
pictures. The size-reduced image compressor compresses the plurality
of size-reduced image signals produced by the size-reduced image
producer.
The size-reduced image producer includes a decompressor and a thinner.
The decompressor decompresses the plurality of compressed main image
signals held by the memory and the thinner performs thinning out
on a plurality of decompressed main image signals produced by the
decompressor and produce the plurality of size-reduced image signals.
In another embodiment of the invention, a size-reduced image producer
produces one of the size-reduced image signals each time picture
taking is made once. The size-reduced image signals produced by
the size-reduced image producer are temporarily held the memory.
The size-reduced image compressor compresses a plurality of size-reduced
image signals held by the memory after ending the successive taking
of pictures.
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 part of operation of the FIG. 1 embodiment;
FIG. 3 is an illustrative view showing a configuration of another
embodiment of the invention; and
FIG. 4 is a flowchart showing part of operation of the FIG. 3 embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a digital camera 10 of this embodiment includes
a CCD imager (image sensor) 12. The CCD imager 12 has a light-receiving
surface covered by a color filter (not shown) so that an optical
image of a subject is illuminated through the color filter onto
the light-receiving surface.
When an operator switches a mode-selector switch 37 to a "CAMERA"
side, the system controller 36 establishes a camera mode. Thereupon,
the CPU 32 instructs a timing generator (TG) 14 to perform thinning-out
reading so that the CCD imager 12 is driven in the thinning-out
reading scheme by the TG 14. Due to this, low-resolution camera
signals (pixel signals) corresponding to the subject image are outputted
from the CCD imager 12.
The output camera signal is subjected to well-known noise removal
and level adjustment in a CDS/AGC circuit 16 and then converted
into a digital signal by an A/D converter 18. A signal processing
circuit 20 produces a YUV signal on the basis of the A/D-converted
camera signal and supplies the produced YUV signal together with
a write request to a memory control circuit 22. The YUV signal is
written to an SDRAM 24 by a memory control circuit 22.
On the other hand, a video encoder 26 sends a read request to the
memory control circuit 22. The memory control circuit 22 reads a
YUV signal from the SDRAM 24 in response to that request. The video
encoder 26 fetches the YUV signal thus read-out and converts the
fetched YUV signal into a composite image signal. The converted
composite image signal is outputted onto a monitor 28. As a result,
real-time motion images (through-images) of the subject is displayed
on the monitor 28.
When a shutter button 38 is pressed in a state that a successive-picture-taking
mode on-off switch 40 is set to an "OFF" side, the system
controller 36 outputs a corresponding control signal. At this time,
a CPU 32 instructs the TG 14 to perform all-pixel reading. The TG
14 drives the CCD imager 12 in the all-pixel reading scheme on a
one-screen-period basis. Due to this, a high-resolution camera signal
in one screen is outputted from the CCD imager 12. That is, picture
taking of a subject is made once, and a camera signal corresponding
to a taken subject image is outputted from the CCD imager 12. The
output camera signal is processed similarly to the above and a high-resolution
YUV signal is secured within the SDRAM 24.
Note that a high-resolution YUV signal obtained by operating the
shutter button 38 is hereinafter defined as a main image signal.
Also, the main image signal is secured in a main image area 24a
of the SDRAM 24.
The CPU 32 also instructs a JPEG CODEC 30 to compress the main
image signal in timing of storing the main signal to the SDRAM 24.
Responsive to a given compression command, the JPEG CODEC 30 first
requests the memory control circuit 22 to read out a main image
signal. The memory control circuit 22 reads a main image signal
out of the main image area 24a in response to this read request
and sends a read main image signal to the JPEG CODEC 30. The JPEG
CODEC 30 performs JPEG compression on the main image signal to thereby
produce a compressed main image signal. Producing the compressed
main image, the JPEG CODEC 30 provides the compressed main image
signal, together with a write request, to the memory control circuit
22. The compressed main image signal is stored to a compressed image
area 24c of the SDRAM 24 by the memory control circuit 22.
After storing the compressed main image signal to the SDRAM 24,
the CPU 32 instructs the memory control circuit 22 to perform thinning-out
on the main image signal secured within the main image area 24a.
The memory control circuit 22 performs vertical thinning-out and
horizontal thinning-out processes on the main image signal in response
to that instruction and creates a thumbnail image signal. The created
thumbnail image signal is stored in a thumbnail image area 24b.
After creating a thumbnail image signal, the CPU 32 instructs the
JPEG CODEC 30 to compress the thumbnail image signal. The JPEG CODEC
30 requests the memory control circuit 22 to read out a thumbnail
image signal in response to the compression instruction and then
performs JPEG compression on a read-out thumbnail image signal.
After producing a compressed thumbnail image signal, the JPEG CODEC
30 provides this compressed thumbnail image signal, together with
a write request, to the memory control circuit 22. The compressed
thumbnail image signal is stored to the compressed image area 24c
by the memory control circuit 22.
After securing the compressed main image signal and compressed
thumbnail image signal within the SDRAM 24 in this manner, the CPU
32 sends a file preparing command and read request to the memory
control circuit 22. The memory control circuit 22 first prepares
an image file conforming to DCF in response to the file preparing
instruction. In this image file is accommodated a compressed main
image signal and compressed thumbnail image signal obtained by the
above process. The memory control circuit 22 subsequently reads
an image file out of the SDRAM 24 in response to a read request
and provides a read-out image file to the CPU 32. The CPU 32 records
the image file given from the memory control circuit 22 onto a memory
card 34.
When the shutter button 40 is pressed in a state that a successive-picture-taking
mode is set by the successive-picture-taking-mode on-off switch
42, successive picture taking is performed by the CCD imager 12.
Main image signals and thumbnail image signals corresponding to
respective subject images thus taken are recorded in a compressed
state to the memory card 34. At this time, the CPU 32 processes
a flowchart shown in FIG. 2.
Referring to FIG. 2, when the shutter button 38 is pressed, the
CPU 32 in step S1 first sets a count value of a counter 32a to "1"
and then, in step S3, instructs the TG14 to perform all-pixel reading.
The TG 14 drives the CCD imager 12 in the all-pixel reading scheme
thereby outputting a high-resolution camera signal in one screen
from the CCD imager 12. That is, the subject is taken once due to
once of all-pixel read instruction, and a camera signal corresponding
to a picture-taken subject image is outputted from the CCD imager
12. The output high-resolution camera signal is processed similarly
to the above. As a result, a main image signal in one screen is
secured in the main image area 24a of the SDRAM 24.
The CPU 32, in step S5, subsequently instructs the JPEG CODEC 30
to compress the main image signal. The JPEG CODEC 30 outputs a read
request to the memory control circuit 22 in response to this instruction
and performs JPEG compression on the main image signal read by the
memory control circuit 22. The JPEG CODEC 30 also outputs the compressed
main image signal produced by the JPEG compression, together with
a write request, to the memory control circuit 22. The compressed
main image signal is stored to the compressed image area 24c of
the SDRAM 24 by the memory control circuit 22.
The CPU 32 advances to step S7 in timing that the compressed main
image signal is secured in the compressed image area 24c, to compare
a current count value N of the counter 32a with a predetermined
value M (M: the number of pictures successively taken). Here, if
the count value N has not reached the predetermined value M, the
CPU 32 proceeds to step S9 and increments the counter 32a in this
step, then returning to the step S3. This result in execution of
M times a series of processes of taking a picture of a subject by
the CCD imager 12, producing a main image signal corresponding to
the taken subject image and compressing the produced main image
signal. Thus, compressed main image signals in the number of M are
secured within the compressed image area 24c.
When the count value N reaches the predetermined value M, the CPU
32 in step S7 determines "YES" and proceeds to processes
of step S11 and the following. At first, in step S11, "1"
is set to the counter 32a. Then, in step S13, the JPEG CODEC 30
is instructed to decompress a compressed image signal corresponding
to the current count value N. The JPEG CODEC 30 requests the memory
control circuit 22 to read out Nth-produced compressed main image
signal and performs JPEG decompression on a compressed main image
signal read out of the compressed image area 24c. The JPEG CODEC
30 furthermore requests the memory control circuit 22 to write the
produced decompressed main image signal. The decompressed main image
signal is written to the main image area 24a of the SDRAM 24 by
the memory control circuit 22.
The CPU 32 advances to step S15 in timing that the decompressed
main image signal is written to the SDRAM 24 and, in this step,
instructs the memory control circuit 22 to perform thinning-out
on the decompressed main image signal. The memory control circuit
22 performs thinning-out on the decompressed main image signal stored
in the main image area 24a to create a thumbnail image signal and
stores a created thumbnail image signal to the thumbnail image area
24b.
After creating the thumbnail image signal, the CPU 32 advances
to step S17 to instruct the JPEG CODEC 30 to compress the created
thumbnail image signal. The JPEG CODEC 30 requests the memory control
circuit 22 to read a thumbnail image signal and performs JPEG compression
on a read thumbnail image signal. Obtaining a compressed thumbnail
image signal, the JPEG CODEC 30 outputs the compressed thumbnail
image signal together with a write request to the memory control
circuit 22. The compressed thumbnail image signal is stored in the
compressed image area 24c by the memory control circuit 22. That
is, both the Nth-produced compressed main image signal and the corresponding
thumbnail image signal are secured within the compressed image area
24c.
The CPU 32 in the succeeding step S19 sends a file preparing instruction
to the memory control circuit 22. The memory control circuit 22
prepares an image file conforming to DCF in the compressed image
area 24c, in response to the instruction. In this image file, the
Nth compressed image signal and the Nth thumbnail image signal will
be accommodated.
In step S21, the current count value N is compared to a predetermined
value M. If N<M, the counter 32a in step S23 is incremented and
then the process returns to the step S13. Due to this, the process
of steps S13 to S23 is repeated until the count value N reaches
the predetermined value M. That is, each compressed main image signal
stored in the compressed image area 24c is subjected to JPEG decompression.
Based on the decompressed main image signal, a thumbnail image signal
is produced. The thumbnail image signal is subjected to JPEG compression.
Then, the compressed main image signal and compressed thumbnail
image signal in mutual correspondence is accommodated in a common
image file. Image files in the number of M are obtained in the compressed
image area 24c.
When the count value N reaches the predetermined value M, the CPU
32 advances to step S25 to record the image files in the number
of M stored in the compressed image area 24c to the memory card
34. That is, the memory control circuit 22 is requested to read
out image files so that the image files read out by the memory control
circuit 22 are recorded onto the memory card 34. After recording
all the image files, the CPU 32 returns to the main routine (not
shown).
According to this embodiment, each time the image sensor takes
one picture of a subject, a compression process on the corresponding
main image signal is made. On the other hand, the compression process
of the thumbnail image signal is first performed after ending the
successive taking of pictures. Specifically, after securing the
compressed main image signals in the number of M within the memory,
each of the compressed main image signals is decompressed so that
a thumbnail image signal is produced on the basis of the decompressed
image signal. Then, a compression process is performed on the thumbnail
image signals in the number of M.
Because the compressed thumbnail image signals are produced after
ending the successive taking of pictures in this manner, it is possible
to shorten the picture-taking interval of the image sensor. Also,
the compression of main image signals in timing of between picture
taking enables to reduce the internal memory capacity.
Referring to FIG. 3, a digital camera 10 of another embodiment
has a thinning-out circuit 20a provided in the signal processing
circuit 20 so that the thinning-out circuit 20a can produce thumbnail
image signals from main image signals. Consequently, the operation
after pressing the shutter button 30, in any of setting and not
setting the successive picture-taking mode, is different from that
of the FIG. 1 to FIG. 2 embodiment. However, the through-image display
process before pressing the shutter button 38 is the same as that
of the FIG. 1 to FIG. 2 embodiment. Hence, the through-image display
process is omitted of explanation.
When the shutter button 38 is pressed in a state that the successive
picture-taking mode is off, the CPU 32 instructs the TG 14 to perform
all-pixel reading. The TG 14 drives the CCD imager 12 by the all-pixel-reading
scheme thereby outputting one-screen camera signals corresponding
to a subject image from the CCD imager 12. The output camera signal
is inputted to the signal processing circuit 20 through the CDS/AGC
circuit 16 and A/D converter 18.
In the signal processing circuit 20, a main image signal is produced
on the basis of the input camera signal wherein, in the thinning-out
circuit 20a, a thumbnail image signal is produced from the main
image signal. That is, the thinning-out circuit 20a performs vertical
and horizontal thinning-out processing on the main image signal
thereby producing a thumbnail image signal. The signal processing
circuit 20 outputs the produced main image signal and thumbnail
image signal, together with a write request, to the memory control
circuit 22. The main image signal and the thumbnail image signal
are respectively written to the main image area 24a and the thumbnail
image area 24b of the SDRAM 24 by the memory control circuit 22.
The CPU 32 first instructs, in timing of securing the main image
signal and thumbnail image signal within the SDRAM 24, the JPEG
CODEC 30 to compressed the main image signal. The JPEG CODEC 30
requests, in response to this instruction, the memory control circuit
22 to read out a main image signal and performs JPEG compression
on a main image signal read out of the main image area 24a by the
memory control circuit 22. Obtaining a compressed main image signal,
the JPEG CODEC 30 instructs the memory control circuit 22 to write
the compressed main image signal. The compressed main image signal
is thus written to the compressed image area 24c of the SDRAM 24
by the memory control circuit 22.
The CPU 32 subsequently instructs the JPEG CODEC 30 to compress
the thumbnail image signal. Consequently, the thumbnail image signal
is also processed similarly to the above. That is, the thumbnail
image signal secured in the thumbnail image area 24b is read out
by the memory control circuit 22 and subjected to JPEG compression
by the JPEG CODEC 30. Then, the produced compressed thumbnail image
signal is stored to the compressed image area 24c by the memory
control circuit 22.
After obtaining both the compressed main image signal and the compressed
thumbnail image signal in this manner, the CPU 32 instructs the
memory control circuit to prepare an image file. The memory control
circuit 22 prepares an image file conforming to DCF, in response
to the file-preparing instruction. In the image file, the compressed
main image signal and the compressed thumbnail image signal will
be accommodated. The CPU 32 further sends to the memory control
circuit 22 a request to read out this image file and then fetches
a read image file read by the memory control circuit 22. The fetched
image file is recorded onto the memory card 34.
When the shutter button 38 is pressed in a state that the successive
picture-taking mode is on, the CPU 32 processes a flowchart shown
in FIG. 4. At first, in step S31 the count value N of the counter
32a is set to "1". Then, in step S33, the TG 14 is instructed
to perform all-pixel reading. The TG 14 drives the CCD imager 12
by the all-pixel reading scheme and outputs one-screen camera signals
from the CCD imager. That is, a subject is taken once due to one
instruction of all-pixel reading so that a camera signal corresponding
to the a subject image thus taken is outputted from the CCD imager
12. The output camera signal is processed similarly to the above,
and the corresponding main image signal and the thumbnail image
signal are stored respectively in the main image area 24a and the
thumbnail image area 24b of the SDRAM 24.
The CPU 32 advances, in timing of securing the main image signal
and thumbnail image signal to the SDRAM 24, to step S35 where it
instructs the JPEG CODEC to compress the main image signal. The
JPEG CODEC 30 instructs, in response to the compression instruction,
the memory control circuit 22 to read out a main image signal and
performs JPEG compression on a main image signal read out of the
main image area 24a by the memory control circuit 22. Obtaining
a compressed main image signal, the JPEG CODEC 30 requests the memory
control circuit 22 to write this compressed main image signal. The
compressed main image signal is thus written to the compressed image
area 24c of the SDRAM 24 by the memory control circuit 22.
The CPU 32 advances, in timing of storing the compressed main image
signal to the SDRAM 24, to step S37 where it compares the current
count value N with a predetermined value M. If N<M, the counter
32a in step S39 is incremented and then the process returns to the
step S33. Consequently, a series of processes of steps S33 to S39
are repeated until the count value N reaches M. At a time of reaching
the count value N=predetermined value M, thumbnail image signals
in the number of M are obtained within the thumbnail image area
24b and compressed main image signals in the number of M are within
the compressed image area 24c.
If "YES" is determined in the step S37, the CPU 32 in
step S41 sets the count value N again to "1" and subsequently,
in step S43, instructs JPEG CODEC 30 to compress a thumbnail image
signal corresponding to the current count value N. The JPEG CODEC
30 instructs the memory control circuit 22 to read out an Nth-produced
thumbnail image signal and performs JPEG compression on a thumbnail
image signal read out of the thumbnail image area 24b by the memory
control circuit 22. The JPEG CODEC 30 further requests the memory
control circuit 22 to write the produced compressed thumbnail image
signal. Due to this, the compressed thumbnail image signal is written
to the compressed image area 24c.
The CPU 32 thereafter, in step S45, sends a file preparing instruction
to the memory control circuit 22. The memory control circuit 22
prepares, in response to this instruction, an image file conforming
to DCF in the compressed image area 24 and accommodates an Nth compressed
main image signal and compressed thumbnail image signal in this
image file. In the following step S47, it is determined whether
the current count value N is equal to the predetermined value M.
If "NO", the counter 32a in step S47 is incremented and
then the process returns to the step S43. The process of the steps
S43 to S47 is repeated M times. As a result, image files in the
number of M accommodating therein the mutually-corresponded compressed
main image signals and compressed thumbnail image signals within
the compressed image area 24c.
When the count value N reaches the predetermined value M, the CPU
32 advances to step S51 where it performs a record process for the
image files in the number of M stored in the SDRAM 24. That is,
the memory control circuit 22 is requested to read out an image
file and records an image file read out by the memory control circuit
22 onto the memory card 34. Such a process is repeated M times,
thereby recording all the image files in the number of M to the
memory card 34. Completing the recording process, the CPU returns
to the main routine (not shown).
According to this embodiment, each time the image sensor takes
one picture, a main image signal and thumbnail image signal is produced
and the main image signal is compressed. At a time of ending successive
picture taking, compressed main image signals in the number M and
thumbnail image signals in the number of M are secured within the
memory. The compression process on the thumbnail image signals is
performed after ending the successive picture taking, thereby providing
compressed thumbnail image signals in the number of M.
In this manner, no compression process is done for the thumbnail
image signals between the picture taking in the present time and
the picture taking in the next time. That is, the compression process
of thumbnail image signals, conventionally made between picture
taking operations, is postponed up to the end of successive picture
taking. This reduces the time interval of taking pictures. Also,
compressing the main image signal between taking pictures reduces
the internal memory capacity.
Incidentally, although the above embodiment takes picture of a
subject by the CCD-type image sensor, it is needless to say that
a CMOS-type image sensor may be used in place thereof. Also, although
in the embodiment the image-file recording medium used a semiconductor
memory, it is needless to say that a disk recording medium may be
used in place 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.
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