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Digital Camera Patent Abstract
A digital camera capable of compensating a portion of a captured
image with another image without putting a squeeze on storage capacity.
The digital camera has a plurality of image-capturing systems capable
of essentially simultaneously capturing images of a single subject
at mutually-different angles of view. Information about relevant
image data which are items of the other simultaneously-captured
image data is imparted as relevant information to at least one item
of image data among items of image data captured by the plurality
of image-capturing systems. The image data imparted with the relevant
information and the relevant image data captured simultaneously
with the image data are stored as separate items of data in user
memory which serves as storage means.
Digital Camera Patent Claims
1. A digital camera comprising:a plurality of image-capturing systems
which essentially simultaneously capture images of a single subject
at mutually-different angles of view;an associating unit which imparts,
to at least one of a plurality of items of image data captured by
means of image-capturing actions of the plurality of image-capturing
systems, relevant information indicating association with relevant
image data which are items of the other simultaneously-captured
image data; anda storage unit for storing the image data imparted
with the relevant information and the relevant image data as separate
items of data.
2. The digital camera according to claim 1, wherein the relevant
information includes file names of the relevant image data.
3. The digital camera according to claim 1, wherein the relevant
information includes coordinate information showing a reference
position of an image range overlapping the relevant image.
4. The digital camera according to claim 1, wherein the relevant
information includes magnifying power which is a ratio among sizes
of figures in the plurality of simultaneously-captured images.
5. A data management method for a digital camera which essentially
simultaneously captures images of a single subject through use of
a plurality of image-capturing systems in order to compensate a
portion of a captured image with a relevant image captured at a
different angle of view essentially simultaneously with the image,
the method comprising the steps of:imparting, to at least one of
a plurality of items of image data captured by means of image-capturing
actions of the plurality of image-capturing systems, relevant information
indicating association with relevant image data which are items
of the other simultaneously-captured image data; andstoring in a
storage unit the image data imparted with the relevant information
and the relevant image data as separate items of data.
Digital Camera Patent Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001]This application claims priority to Japanese Patent Application
No. 2005-374823, filed on Dec. 27, 2005, which is incorporated herein
by reference in its entirety.
FIELD OF THE INVENTION
[0002]The present invention relates to a digital camera having
a plurality of image-capturing systems, as well as to a method for
managing data in the digital camera.
Related Art
[0003]A technique for compensating for a portion of a captured
image with another item of image data has been known. One of such
compensation techniques is for synthesizing image data of comparatively
low resolution with image data of comparatively high resolution,
to thus prepare image data which have high resolution in only a
noteworthy portion thereof This is a technique useful for, e.g.,
a portrait. In a portrait, a person is a main subject, and the area
of the person can be said to be an area which gains the user's attention.
Such an area of the person is desirably of high resolution. In contrast,
even when the definition of a background around the person has become
slightly degraded, the user has little complaint. In order to capture
the background as well as the person with high resolution, an enormous
number of CCD elements are required, which in turn renders a camera
expensive. For this reason, in a known technique, telescopic image
data formed by capturing essentially only a person are synthesized
with a wide-angle image formed by capturing the person and a background
thereof. In this case, the number of pixels assigned to the area
of the person in the telescopic image is greater than the number
of pixels assigned to the same in the wide-angle image. The telescopic
image can be said to be of higher definition in connection with
the area of the person. Accordingly, the area of the person in the
telescopic image is pasted to the area of the person in the wide-angle
image, whereby an image which is of high resolution in only a noteworthy
portion thereof is acquired.
BACKGROUND OF THE INVENTION
[0004]Japanese Patent Laid-Open Publication No. 2003-298919 describes
a digital camera having such synthesis means. The digital camera
described in the publication comprises an image-capturing system
having a telescopic lens and an image-capturing system having a
wide-angle lens. A single subject can be captured essentially simultaneously
at different angles of view by means of both image-capturing systems.
This digital camera synthesizes a wide-angle view and a telescopic
view, both of which have been obtained through image-capturing operation,
and stores the thus-synthesized image.
[0005]Although the digital camera described in the patent publication
stores a synthesized image, large-capacity storage means is required,
because the synthesized image is large in file size. When a wide-angle
view and a telescopic view are synthesized together, the number
of pixels of the wide-angle view is usually increased by means of
interpolation so as to match the number of pixels of the telescopic
image, and the wide-angle image complemented with the pixels and
the telescopic image are synthesized together. As a result, the
file size of the synthesized image data is significantly increased.
[0006]For instance, each of a pre-interpolation wide-angle image
and a telescopic image is assumed to have 2592 (width).times.1944
(length) pixels (about 5 million pixels). A wide-angle lens used
for capturing a wide-angle image has a 35 mm-film equivalent focal
length of 48 mm, and the telescopic lens used for capturing a telescopic
image has a 35 mm-film equivalent focal length of 96 mm. In this
case, the range of a field expressed by one pixel in a wide-angle
image is expressed by four pixels in the telescopic image. For instance,
when an image of an object of predetermined size has been captured,
the object is expressed by "n" pixels in a wide-angle
of image and expressed by n.times.4 pixels in a telescopic image.
In other words, a scale of 1:2 exists between a wide-angle image
and a telescopic image.
[0007]In order to synthesize the telescopic image and the wide-angle
image together without involvement of a decrease in the number of
pixels of the telescopic image, the wide-angle image must have been
previously enlarged double in both the vertical and horizontal directions
by means of interpolating pixels. More specifically, the wide-angle
view must have been enlarged to an image of 5184.times.3888 pixels.
The number of pixels of a synthesized image, which is obtained by
synthesizing the wide-angle image having undergone pixel interpolation
with the telescopic image, comes to as many as about 20 million.
[0008]An increase in file size resulting from synthesis of the
images becomes more noticeable with increasing ratio of the focal
length of the wide-angle image to the focal length of the telescopic
image. When the focal length ratio is assumed to be "n,"
the number of pixels of the synthesized image is simply calculated
as n.sup.2 times the number of pixels of a pre-synthesis image.
The synthesized image of such large volume puts a significant squeeze
on the finite storage capacity of the digital camera.
SUMMARY OF THE INVENTION
[0009]Therefore, the present invention provides a digital camera
capable of compensating for a portion of a captured image with another
image without putting a squeeze on storage capacity, as well as
providing a method for managing data in the digital camera.
[0010]The present invention provides a digital camera comprising:
[0011]a plurality of image-capturing systems which essentially
simultaneously capture images of a single subject at mutually-different
angles of view;
[0012]an associating unit which imparts, to at least one of a plurality
of items of image data captured by means of image-capturing actions
of the plurality of image-capturing systems, relevant information
indicating association with relevant image data which are items
of the other simultaneously-captured image data; and
[0013]a storage unit for storing the image data imparted with the
relevant information and the relevant image data as separate items
of data.
[0014]In a preferred mode, the relevant information includes file
names of the relevant image data. Further, the relevant information
desirably includes coordinate information showing a reference position
of an image range overlapping the relevant image. Moreover, the
relevant information includes magnifying power, which is a ratio
among sizes of figures in the plurality of simultaneously-captured
images.
[0015]Another present invention provides a data management method
for a digital camera which essentially simultaneously captures images
of a single subject through use of a plurality of image-capturing
systems in order to compensate a portion of a captured image with
a relevant image captured at a different angle of view essentially
simultaneously with the image, the method comprising the steps of:
[0016]Imparting, to at least one of a plurality of items of image
data captured by means of image-capturing actions of the plurality
of image-capturing systems, relevant information indicating association
with relevant image data which are items of the other simultaneously-captured
image data; and
[0017]storing in a storage unit the image data imparted with the
relevant information and the relevant image data as separate items
of data.
[0018]According to the present invention, a plurality of files
that have been essentially simultaneously captured are stored as
separated items of data. Therefore, when compared with a conventional
technique of synthesizing a plurality of images and storing the
thus-synthesized file, a data size required for storage of data
can be reduced. Further, relevant information is retained, and hence
compensation using another image of the simultaneously-captured
images can be performed as required.
[0019]The invention will be more clearly comprehended by reference
to the embodiments provided below. However, the scope of the invention
is not limited to these embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020]Preferred embodiments of the present invention will be described
in detail based on the following figures, wherein:
[0021]FIG. 1 is a perspective view of a digital camera of an embodiment
of the present invention when viewed from the front;
[0022]FIG. 2 is a perspective view of the digital camera when viewed
from the back thereof;
[0023]FIG. 3 is a block diagram showing the configuration of the
digital camera;
[0024]FIG. 4 is a flowchart showing the flow of image-capturing
operation;
[0025]FIG. 5 is a view showing the configuration of an image file;
[0026]FIGS. 6A and 6B are conceptual renderings of first and second
images;
[0027]FIGS. 7A to 7C are views showing the manner in which a captured
image is displayed on a liquid-crystal monitor;
[0028]FIG. 8 is a view showing the manner of moving a display position
in the liquid-crystal monitor;
[0029]FIG. 9 is a view showing the manner of printing a portion
of the first image while compensating the same with the second image;
and
[0030]FIG. 10 is a view showing example interpolation of pixels
performed when the first image and the second image are synthesized
together.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031]An embodiment of the present invention will be described
hereinbelow by reference to the drawings. FIG. 1 is a perspective
view of a digital camera 10 which is an embodiment of the present
invention when viewed from the front; FIG. 2 is a perspective view
of the digital camera 10 when viewed from the back thereof; and
FIG. 3 is a block diagram showing the configuration of the digital
camera 10.
[0032]This digital camera 10 has two mutually-independent image-capturing
systems. A first image-capturing system 20 has a first image-capturing
lens system 21 having a fixed focal length, and forms an image of
a subject on a first image-capturing element 22. A second image-capturing
system 30 has a second image-capturing zoom lens system 31, and
forms the image of the subject on a second image-capturing element
32.
[0033]The first image-capturing element 22 and the second image-capturing
element 32 are equal to each other in an aspect ratio as well as
in the number of CCD elements. Therefore, the first image-capturing
system 20 and the second image-capturing system 30 of the same screen
size and are arranged so as to be able to capture image data of
the same number of pixels. However, there is no necessity for the
two image-capturing elements to have the same number of pixels,
and the image-capturing elements may differ in the number of pixels.
[0034]As mentioned previously, the first image-capturing lens system
21 is a lens of fixed focal length. The focal length of the first
image-capturing lens system 21 is shorter than the focal length
achieved at a short focal length end of the second image-capturing
zoom lens system 31. For instance, a fixed focal length lens having
a 35 mm-film equivalent focal length of 23 mm can be used as the
first image-capturing lens system 21, and a zoom lens having a 35
mm-film equivalent focal length of 39 to 117 mm can be used as the
second image-capturing lens system 31. So long as the first image-capturing
system 20 can capture an image which is wider than that captured
by the second image-capturing system 30, or conversely the second
image-capturing system 30 can capture an image which is more telescopic
than that captured by the first image-capturing system 20, both
the first image-capturing lens system 21 and the second image-capturing
lens system 31 may be zoom lenses or fixed focal length lenses.
[0035]As will be described later, the first image-capturing system
20 and the second image-capturing system 30 can also be used alone
or simultaneously. The first image-capturing system 20 and the second
image-capturing system 30 can essentially simultaneously capture
a single subject. Consequently, two images of the single subject,
which have been captured essentially simultaneously, can be obtained
at mutually-different angles of view.
[0036]Two mutually-independent signal processing sections 26, 36
are provided at a stage subsequent to the two image-capturing systems
20, 30. The two signal processing sections 26, 36 subject image
signals output from the corresponding image-capturing systems 20,
30 to predetermined processing.
[0037]The first signal processing section 26 is provided with an
analogue image processing circuit 23, an AD conversion circuit 24,
and buffer memory 25. An image signal output from the first image-capturing
system 20 is subjected to clamp processing and amplification processing
in the analogue image processing circuit 23. Subsequently, after
having undergone A/D conversion processing in the AD conversion
circuit 24, the image signal is temporarily stored in the buffer
memory 25 as first digital image data.
[0038]The second signal processing section 36 has the same configuration
as that of the first signal processing section 26, and is equipped
with an analogue image processing circuit 33, an AD conversion circuit
34, and buffer memory 35. The image signal output from the second
image-capturing system 30 is subjected to clamp processing, amplification
processing, and AD conversion processing, and is then temporarily
stored in the buffer memory 35 as second digital image data.
[0039]In accordance with a command from a CPU 50, a multiplexer
40 selects either one of the buffer memory 25 and the buffer memory
35, to thereby fetch the image data temporarily stored in the selected
buffer memory. The thus-fetched image data are output to an image
signal processor 60 in a subsequent stage.
[0040]The image signal processor 60 subjects received image data
to various processing operations, such as y correction, color correction,
white balance processing, image compression processing, and the
like. The image signal processor 60 also generates header data appropriate
to respective image data. The thus-generated header data are recorded
in one file along with the image data, and are output as an image
file to buffer memory 62. The header data include photography condition
information such as a date and time of photography, the amount of
exposure, and the like; image information showing thumbnail images
and data sizes of respective items of image data; and information
about other image data captured simultaneously with the image data.
The header data will be described in detail later.
[0041]The buffer memory 62 is work memory, and an image file output
from the previously-described image signal processor 60, an image
file read from memory 70, and the like are temporarily recorded
in the buffer memory 62. The user memory 70 is storage means used
for recording and retaining captured image files. In response to
a user command, a determination is made as to whether or not the
captured image is to be stored in the user memory 70. Specifically,
captured image data are displayed on a liquid-crystal monitor 80.
After having ascertained details of the image displayed on the liquid-crystal
monitor 80, the user issues a command as to whether or not to store
the image file in the user memory 70.
[0042]The liquid-crystal monitor 80 is display means for displaying
the image data instructed by the user from among captured image
data and the image data stored in the user memory 70. This liquid-crystal
display monitor 80 is usually lower than the image data in terms
of the number of pixels. Therefore, when image data are displayed
on the liquid-crystal monitor 80, the image data are subjected to
display processing in the image signal processor 60.
[0043]The CPU 50 controls the entire sequence of the camera in
response to an input from an operation section 90 formed from a
plurality of switches and the like, thereby executing various jobs
associated with image-capturing operation. The operation section
90 is a user interface which receives a command from the user, and
is formed from a release button 91, a zoom button 92, a cross-key
pad 93, a switching lever 94, a playback button 95, and the like.
The release button 91 is a button which receives a command for image-capturing
operation. When depressed halfway down (in a "first release
state"), the release button 91 receives an image-capturing
standby command. When depressed all the way down (in a "second
release state"), the release button 91 receives an image-capturing
command. The zoom button 92 is a button used for instructing the
amount of zoom of the second image-capturing lens 31. The switching
lever 94 is a lever capable of selecting one from three positions;
namely, a position Z (zoom), a position W (wide), and a position
C (combination). When the switching lever 94 is situated at "Z,"
the second image-capturing system 30 is commanded to solely capture
an image. When the switching lever 94 is situated at "W,"
the first image-capturing system 20 is commanded to solely capture
an image. When the switching lever 94 is situated at "C,"
the first and second image-capturing systems 20, 30 are commanded
to simultaneously capture an image.
[0044]Further, the digital camera 10 comprises various types of
members provided in the known digital camera 10, such as a zoom/AE/AF
control section 100 for performing AF control, AE control, zoom
control, and the like, during capture of an image; a strobe firing
section 110; and others. The configurations and features of these
members are analogous to those provided conventionally, and hence
their explanations are omitted.
[0045]Flow of image-capturing operation of the digital camera 10
will now be described briefly. FIG. 4 is a flowchart showing flow
of image-capturing operation performed by the digital camera 10.
When the release button 91 is depressed halfway down and brought
into a first release state (S1001), image-capturing operation is
started. When the first release state is detected, the CPU 50 ascertains
the position of the switching lever 94 (S1002). When the switching
lever 94 is situated at the position "W," image-capturing
operation is performed solely by the first image-capturing system
20. Specifically, the first image-capturing system 20 is switched
to an operating state (S1003). Subsequently, AE (Autoexposure) for
determining the optimum amount of exposure is performed on the basis
of the amount of incident light, and the like (S1004). In this state,
the release button 91 waits for being depressed all the way down
to thus enter a second release state (S1005). When the release button
has entered the second release state, the electric charges accumulated
in the first image-capturing element 22 are emitted once, and the
electric charges are accumulated for a period of time during which
a predetermined amount of exposure is achieved, and image-capturing
operation is performed (S1006). The image signal obtained by means
of image-capturing operation is subjected to predetermined processing
in the signal processing section 26, and the signal is then delivered
to the buffer memory 25. The multiplexer 40 fetches the image data
temporarily stored in the buffer memory 25, and sends the image
data to the image signal processor 60 (S1007). The image signal
processor 60 subjects received image data to predetermined image
processing, to thus prepare header data for the image data, and
creates an image file including the image data and the header data
(S1008).
[0046]After having been temporarily stored in the buffer memory
62, the image data generated by the image signal processing processor
60 is displayed on the liquid-crystal monitor 80 (S1009). Upon ascertainment
of details of the displayed image data, the user issues a command
to record the image data, when necessary. When a command to record
an image has been issued by the user, the image data are recorded
in the user memory 70 (S1010).
[0047]Turning back to step S1002, flow of processing performed
when the switching lever 94 is situated at the position Z (zoom)
will now be described. This case is essentially analogous to the
case where the switching lever 94 is situated at the position W
(wide). When the switching lever 94 is situated at the position
Z (zoom), the second image-capturing system 30 is brought into an
operating state (S1011). Subsequently, AE responsive to the amount
of incident light, AF (autofocus) responsive to a distance to a
subject, and zooming action responsive to the amount of zoom commanded
by the user are performed (S1012). In this state, the release button
91 waits for being depressed all the way down to thus enter the
second release state (S1013). When the release button has entered
the second release state, the electric charges accumulated in the
second image-capturing element 32 are emitted once, and the electric
charges are accumulated for a period of time during which a predetermined
amount of exposure is achieved, and image-capturing operation is
performed (S1014). The image signal obtained by means of image-capturing
operation is subjected to predetermined processing in the signal
processing section 36, and the signal is then delivered to the buffer
memory 35. The multiplexer 40 fetches the image data temporarily
stored in the buffer memory 35, and sends the image data to the
image signal processor 60 (S1015). The image signal processor 60
subjects received image data to predetermined image processing,
to thus prepare header data for the image data, and creates an image
file including the image data and the header data (S1016).
[0048]After having been temporarily stored in the buffer memory
62, the image data generated by the image signal processing processor
60 are displayed on the liquid-crystal monitor 80 (S1017). Upon
ascertainment of details of the displayed image data, the user issues
a command to record the image data, when necessary. When a command
to record an image has been issued by the user, the image data are
recorded in the memory (S1018).
[0049]Turning back to step S1002, flow of processing performed
when the switching lever 94 is situated at the position C (combination)
will now be described. In this case the first image-capturing system
20 and the second image-capturing system 30 simultaneously perform
image-capturing operations. Therefore, the CPU 50 brings the first
image-capturing system 20 and the second image-capturing system
30 into operating state (S1020). The first image-capturing system
20 and the second image-capturing system 30 perform AE responsive
to the amount of incident light. In the case of the second image-capturing
system 30 having a zoom lens, AF and zooming are further performed
(S1021). In this state, the camera waits until the release button
enters the second release state (S1022).
[0050]When the second release state has been detected, the electric
charges accumulated in the first image-capturing element 22 and
the second image-capturing element 32 are emitted once, and the
electric charges are accumulated for a period of time during which
a predetermined amount of exposure is achieved, and image-capturing
operation is performed (S1023). In the first image-capturing element
22 and the second image-capturing element 32, emission of the electric
charges and timing of accumulation are basically identical. The
first image-capturing system 20 and the second image-capturing system
30 substantially simultaneously perform image-capturing operation.
[0051]Image signals obtained through image-capturing actions are
subjected to predetermined processing in the corresponding signal
processing sections 26, 36, and the thus-processed signals are temporarily
stored in the corresponding buffer memories 25, 35. The multiplexer
40 fetches the first image data temporarily stored in the buffer
memory 25 assigned to the first image-capturing system 20 among
the two buffer memories 25, 35, and outputs the thus-fetched first
image data to the image signal processor 60 (S1024). The image signal
processor 60 subjects the first image data to predetermined image
processing, to thus prepare header data, and creates an image file
including the image data and the header data (S1025). The first
image data having undergone these processing operations are temporarily
stored in the buffer memory 62.
[0052]Subsequently, the multiplexer 40 fetches the second image
data temporarily stored in the buffer memory 35 assigned to the
second image-capturing system 30, and sends the image data to the
image signal processor 60 (S1026). The image signal processor 60
subjects the second image data to predetermined image processing,
to thus prepare header data for the image data, and creates an image
file including the image data and the header data (S1027). The second
image data having undergone these processing operations are temporarily
stored in the buffer memory 62 along with the first image data.
[0053]Subsequently, the capturing image data are displayed on the
liquid-crystal monitor 80 (S1028). The image data displayed are
basically first image data. The first image data are wide-angle
image data captured by the first image-capturing system 20 having
a fixed focal length lens. Therefore, the entirety of a captured
image can be ascertained by displaying the first image data corresponding
to the wide-angle image. In accordance with a user command, the
second image data may be displayed, or the first image data and
the second image data may be displayed simultaneously.
[0054]Upon ascertainment of details of the displayed image data,
the user issues a command to record the image data, when necessary.
When a command to record an image has been issued by the user, the
first image data and the second image data are recorded in the memory
70 (S1029).
[0055]The configuration of an image file generated by the digital
camera 10 will now be described by reference to FIG. 5. FIG. 5 is
a view showing the configuration of an image file obtained in a
combination mode; namely, when the first image-capturing system
20 and the second image-capturing system 30 have simultaneously
performed image-capturing actions. An image file is generally divided
into image data showing details of a captured image and header data
showing various types of pieces of information relating to the image
file. The header data include photography condition information,
image information, and relevant information. The photography condition
information relates to various conditions required when image-capturing
operation has been performed, such as a date and time of the image
data, the amount of exposure, firing/nonfiring of flash light, white
balance settings, and the like. The image information relates to
image data such as thumbnail images and data sizes of respective
items of image data, and the like. The image-capturing condition
information and the image information are pieces of information
frequently used in conventional image files, and hence their detailed
explanations are omitted.
[0056]The relevant information relates to relevant image data which
are other image data obtained by means of simultaneous image-capturing
operations. The relevant information comprises a "simultaneous
image-capturing flag," a "relevant image file name,"
"magnifying power," a "compensation start position
X," and a "compensation start position Y." The "simultaneous
image-capturing flag" shows whether or not the image data have
been captured in the combination mode; in other words, whether or
not another item of simultaneously-captured image data is present.
When the image has been captured in the combination mode, a flag
"1" is recorded. When the image has been captured in the
zoom mode or the wide mode, a flag "0" is recorded.
[0057]When the "simultaneous image-capturing flag" is
"1," a value of the "relevant image file name,"
a value of the "magnifying power," a value of the "compensation
start position X," and a value of the "compensation start
position Y" are successively recorded. In contrast, when the
"simultaneous image-capturing flag" is "0,"
NULL is recorded as values for the respective items.
[0058]The "relevant image file name" is the file name
of a relevant image which is another one of the simultaneously-captured
images. Therefore, the file name of a second image captured by the
second image-capturing system is recorded as the value of the "relevant
image file name" in the header of the first image captured
by the first image-capturing system. The file name of a first image,
which also serves as the value of the "relevant image file
name," is recorded in the header of the second image.
[0059]The ratio between the sizes of figures in the simultaneously-captured
two images is recorded as the "Magnifying power." This
magnifying power is determined by the ratio between the focal length
of the first image (an image captured by the first image-capturing
system) and the focal length of the second image (an image captured
by the second image-capturing system) associated with the first
image and the ratio between a pixel pitch of the first image and
that of the second image. Specifically, when the pixel pitch of
the first image is taken as p1, the focal length of the first image
is taken as f1, the pixel pitch of the second image is taken as
p2, and the focal length of the second image is taken as f2, the
magnifying power M is determined by the following equation.
M=(f2/p2)/(f1/p2)=(f2/f1)(p1/p2) (1).
[0060]In the case of an image-capturing system having a zoom lens,
the focal length is changed as appropriate. In this case, the amount
by which the zoom lens is driven during image-capturing operation
is detected by an encoder provided in a lens drive mechanism, and
a set focal length is calculated from the drive amount, and the
magnifying power M is calculated from the thus-obtained set focal
length.
[0061]This magnifying power M will be described more specifically.
Consideration is now given to a case where a first image having
a 35 mm-film equivalent focal length of 23 mm is captured by use
of the first image-capturing system 20, and a second image having
a 35 mm-film equivalent focal length of 69 mm is captured by use
of the second image-capturing system 30. In this digital camera
10, the first image-capturing element 22 and the second image-capturing
element 32 have the same screen size and the same number of pixels.
Therefore, a ratio of pixel pitches p1/p2 is determined as one.
The magnifying power M is computed by means of solely the ratio
of focal lengths. In the case of the present embodiment, the magnifying
power M is calculated as f2/f1=69/23.apprxeq.3.
[0062]Compensation start position X" and "compensation
start position Y" are pieces of information showing a positional
relationship between the subjects whose images have been captured
in the form of the first image and the second image, and correspond
to an X-coordinate value and a Y-coordinate value in the first image
from where compensation of the second image is to be started. Compensation
of the second image will be described by reference to FIGS. 6A and
6B.
[0063]FIG. 6A is a conceptual rendering of a first image which
is a wide-angle image, and FIG. 6B is a conceptual rendering of
a second image which is a telescopic image. When the first and second
images are equal to each other in terms of a pixel pitch and have
a magnifying power M of 3, the second image becomes equal to an
image which is formed by enlarging the center of the first image
and its vicinity by a factor of about three. Put another word, an
area of about one-third of the center of the first image and its
vicinity falls within the range of the figure captured in the second
image.
[0064]A target which receives the user's attention; for example,
a figure or the like, is often situated at the center of the first
image, and high-definition portraying of the target is desired.
However, in the case of a wide-angle image captured with inclusion
of a background that is the surroundings of the target, and the
like, there are many cases where the target fails to acquire sufficient
resolution. For this reason, there is a case where only the target
is acquired as a telescopic image and the target in the wide-angle
image is compensated with the telescopic image. Various compensation
techniques are available, and the conceivable simplest method is
to paste a telescopic image into the center of a wide-angle image.
Another conceivable method is to replace the center of a wide-angle
image with a telescopic image when the center of the wide-angle
image is displayed in an enlarged manner. In order to perform such
compensating operation, there must have been known in advance a
coordinate position in a wide-angle image corresponding to the position
of a figure at the reference coordinate position [e.g., the position
of coordinates (0,0)] in a telescopic image. To this end, the digital
camera 10 records in an image file a coordinate position in a wide-angle
image, which corresponds to the position of a figure at a reference
coordinate position in a telescopic image, as a "compensation
start position X" and a "compensation start position Y."
[0065]This digital camera 10 records in an image file a coordinate
position of a wide-angle image (a first image) corresponding to
the position of a figure at a position (0,0) in a telescopic image
(a second image) as a "compensation start position X"
and a "compensation start position Y." In the example
shown in FIGS. 6A and 6B, coordinates (a, b) in the first image
indicate the position of the figure which corresponds to coordinates
(0,0) in the second image. Therefore, the coordinates (a, b) are
stored as the "compensation start position X" and the
"compensation start position Y."
[0066]The center of the first image does not necessarily coincide
with the center of the second image, because of an offset between
the position of the first image-capturing lens 21 and that of the
second image-capturing lens 31, a misalignment between the optical
axis of the first image-capturing lens 21 and that of the second
image-capturing lens 31, and the like. Consequently, when the "compensation
start position X" and the "compensation start position
Y" are calculated, the amount of displacement between the centers
of the two images has been calculated in advance from known information,
such as an interval between the first image-capturing lens 21 and
the second image-capturing lens 31, a distance to a subject, a focal
length, and the like. It is better to calculate an accurate "compensation
start position X" and an accurate "compensation start
position Y" from the amount of displacement.
[0067]In the above descriptions, when the image has been captured
in the combination mode, values of the respective items are recorded
in each of the first and second image files. However, the values
of the items may be recorded in only either one of the first image
file and the second image file. When relevant information is stored
in only one of the image files, it is desirable to record the relevant
information in the first image, which is a wide-angle image, by
priority. For instance, the "simultaneous image-capturing flag"
and the "relevant image file name," which have already
been described, may be recorded in the header of the first image
file. In the header of the second image file, the "simultaneous
image-capturing flag" may first be set to 0, and "NULL"
may be recorded in the "relevant image file name" and
the "magnifying power." After the "simultaneous image-capturing
flag" of "1" and the "relevant image file name"
have been recorded in the header of the second image file, "NULL"
may be recorded in the "magnifying power" and the "compensation
start coordinate."
[0068]There will now be described a case where a portion of the
wide-angle image (the first image) may be compensated with the telescopic
image (the second image) by use of an image file including such
relevant information. Compensation of an enlargedly-displayed wide-angle
image is an example compensation of a telescopic image. According
to this compensation, when a wide-angle image is enlargedly displayed
on the liquid-crystal monitor 80 provided in the digital camera
10 and when the number of pixels in the displayed image has become
lower than the number of pixels of the liquid-crystal monitor 80,
a telescopic image is displayed in place of the wide-angle image.
[0069]A specific example will now be described by reference to
FIG. 7. In FIG. 7, each of the first image corresponding to the
wide-angle image and the second image corresponding to the telescopic
image is assumed to have 5 million pixels and a magnifying power
M of 3. The number of pixels of the liquid-crystal monitor 80 is
one million.
[0070]In this state, the user is assumed to have commanded display
of a first image corresponding to a wide-angle image. In this case,
the CPU 50 reads the designated first image and causes the liquid-crystal
monitor 80 to display the entire image. At this time, the liquid-crystal
monitor 80 is smaller than the first image in terms of the number
of pixels. Therefore, when the first image is displayed, the number
of pixels of the first image has been reduced in advance so as to
become equal to the number of pixels of the liquid-crystal monitor
80. In the present embodiment, the first image has five million
pixels whilst the liquid-crystal monitor 80 has one million pixels.
Therefore, the number of pixels of the first image is reduced by
a factor of one-fifth.
[0071]The user is assumed to have commanded to zoom in the display
by a factor of 2 in this state. In this case, about one-fourths
of a range from the center of the first image serves as a display
range E to be displayed on the liquid-crystal monitor 80 (see FIG.
7B). In this case, the number of pixels falling within the display
range E is about 1.25 million pixels, which is greater than the
number of pixels of the liquid-crystal monitor 80. Therefore, in
this case, the area of the first image corresponding to the display
range E is clipped, and the thus-clipped image is matched to the
number of pixels of the liquid-crystal monitor 80. Specifically,
pixels are reduced in such a way that the number of pixels in the
display range is reduced by about 80%. The thus-reduced image is
displayed on the liquid-crystal display 80.
[0072]Subsequently, the user is assumed to have commanded to zoom
in the display by a factor of 2. In this case, about one-eighths
of a range from the center of the first image serves as a display
range E to be displayed on the liquid-crystal monitor 80 (see FIG.
7C). In this case, the number of pixels falling within the display
range E is about 650,000 pixels, which is much smaller than the
number of pixels of the liquid-crystal monitor 80. The CPU 50 does
not display the first image intact. When there is a second image
which is a telescopic image captured simultaneously with the wide-angle
image, the second image is displayed on the liquid-crystal monitor
80.
[0073]Specifically, when the number of pixels included in the display
range E is determined to become smaller than the number of pixels
of the liquid-crystal monitor 80, the CPU 50 ascertains the "simultaneous
image-capturing flag" recorded in the header of the first image
file. When the "simultaneous image-capturing flag" is
set to 0, a simultaneously-captured telescopic image is not present.
In this case, the display range E of the first image is clipped
in an unmodified form, and the number of pixels of the thus-clipped
portion is increased so as to match the number of pixels of the
liquid-crystal monitor 80, and is then displayed on the liquid-crystal
monitor 80.
[0074]Meanwhile, when a value of "simultaneous image-capturing
flag" is set to 1, a value of "relevant image file name,"
a value of "magnifying power," and a value of "compensation
start position" are read, and these values are temporarily
stored. The second image file, which is a relevant image file recorded
in the "relevant image file name," is read. The number
of pixels of the second image is first corrected so as to match
the number of pixels of the liquid-crystal monitor 80, and the second
image is then displayed on the liquid-crystal monitor 80. At this
time, a display range E' in the second image is calculated from
the magnifying power, the compensation start position, and the display
range E in the first image.
[0075]As mentioned above, when the number of pixels included in
the display range E in the first image has become smaller than the
number of pixels of the liquid-crystal monitor 80, the simultaneously-captured
second image is displayed, thereby significantly diminishing degradation
of image quality resulting from enlarged display of the image.
[0076]When the display range E has extended off the figure range
of the second image, the first image is subjected to electronic
zooming (the number of pixels of the first image is increased),
and the thus-zoomed image is displayed on the liquid-crystal monitor
80. As shown in FIG. 8, for instance, the display position is assumed
to have been moved leftward from the position shown in FIG. 7C.
In this case, a portion of the display range E extends off the figure
range of the second image. In this case, the CPU 50 reads the simultaneously-captured
wide-angle image recorded in the header of the second image file;
namely, the file name of the first image, and displays the thus-read
first image. The display range E in the first image is calculated
from the magnifying power, the compensation start position, and
the display range E' in the second image. At that moment, the number
of pixels in the display range E of the first image is smaller than
the number of pixels of the liquid-crystal monitor 80. Therefore,
when the display range E of the first image is displayed on the
liquid-crystal monitor 80, the number of pixels in the display range
E has been increased in advance by means of interpolation, so as
to match the number of the pixels of the liquid-crystal monitor
80. In this embodiment, when a portion of the display range E has
extended off the figure range of the second image, the entire display
range E is replaced with the first image. However, it may be the
case that only the area having extended off the range is replaced
with the first image. Specifically, for the case of the embodiment
shown in FIG. 8, the first image may be displayed in an area D having
extended off the display range E, and the second image may be displayed
in the other area.
[0077]The method for compensating for the image display on the
liquid-crystal monitor 80 built in the digital camera 10 has been
described. This compensation method can be applied to a case where
an image is displayed on another display device; e.g., a monitor
of a personal computer, and the like. Specifically, in a case where
the first image is displayed in an enlarged manner on the monitor
of the personal computer, when the number of pixels in the first
image within the display range has become smaller than the number
of pixels of the monitor, the second image may also be displayed.
[0078]Another embodiment where a portion of a wide-angle image
(the first image) is compensated with the telescopic image (the
second image) will now be described. Compensation performed during
printing is conceivable as another example compensation using a
telescopic image. When a digital image is printed, a pixel density
of 200 dpi or more is usually said to be required for an output
print. In order to fulfill conditions of a pixel density of 200
dpi or more in an image of 2592 (width).times.1944 (height) pixels
(about 5 million pixels), there is no way but to reduce a print
size to 12.96 inches (329 mm).times.9.72 inches (247 mm) or less.
In order to obtain an output print of larger size, there is a necessity
for reducing image quality or capturing an image with an image-capturing
element of higher resolution. However, the reduction in image quality
poses a problem of causing dissatisfaction on the user's part. The
use of a higher-resolution image-capturing element poses a problem
of a necessity for an expensive camera for capturing an image.
[0079]In general, high image quality is not required over the entire
range of a captured image. Particularly, for the case of a portrait,
high attention is paid to the center portion of an image where a
person is located. However, in many cases, low attention is paid
to the periphery of the person; namely, the degree of attention
paid to a background is low. In the case of an image where high
attention is paid to only a part of the image, the user's satisfaction
can be attained by means of printing only the portion of interest
with high quality.
[0080]As in the case of the embodiment, when the wide-angle image
(the first image) and the telescopic image, which are formed by
means of having essentially simultaneously captured a single subject,
are stored in an associated manner, compensating only a portion
of interest for the user (the center portion of the image) of the
wide-angle image with the telescopic image and printing the thus-compensated
image can be conceived.
[0081]Specifically, by reference to FIG. 9, there will now be described
a case where the first image of 2592 (width).times.1944 (height)
pixels (about 5 million pixels) is printed to a size of 38.9 inches.times.29.2
inches. When the user has commanded printing of the first image,
a printer driver calculates a pixel density of an output print from
the number of pixels of the image and the print size specified by
the user. When the obtained pixel density is a predetermined reference
value; e.g., 200 dpi, or less, the printer driver ascertains the
value of the flag in the simultaneously-captured image recorded
in the header of the first image file. In the case of the present
embodiment, the pixel density achieved after printing is about 67
dpi, and the printer driver ascertains the values of the flag in
the simultaneously-captured image. Consequently, when the value
of the flag in the simultaneously-captured image is 0; namely, when
a simultaneously-captured relevant image is not available, the printer
driver performs ordinary print processing. Specifically, the printer
driver generates print data by means of converting the first image
into a printer language, and performs print processing on the basis
of the print data. The pixel density achieved through printing is
about 67 dpi.
[0082]Meanwhile, when the value of the flag in the simultaneously-captured
image is "1"; namely, when two simultaneously-captured
telescopic images are present, the names of the image files, magnifying
power, and the compensation start position are read. The size of
the second image, which is achieved by means of compensating for
a portion of the first image with the second image in accordance
with the print size and the magnifying power, is calculated as a
compensation size. The term "compensation size" refers
to the size of the second image achieved when the first image is
printed after the portion of the first image has been compensated
with the second image. In the present embodiment, when magnifying
power M is three, about one-third of the first image is replaced
with the second image. Accordingly, the compensation size is one-third
of the print size; namely, about 12.96 inches.times.9.72 inches.
When the compensation size has been calculated, pixel density used
for printing the second image is next calculated from the compensation
size and the number of pixels of the second image. On condition
that the second image has the same number of pixels as does the
first image, the pixel density achieved during printing of the second
image is about 200 dpi. The range of the first image which is compensated
with the second image; namely, the range where replacement is to
be performed, is calculated from the compensation size and the compensation
start position as a compensation range Ez.
[0083]After completion of the calculation, the printer driver generates
print data used for printing the image that has been formed by replacing
the compensation range of the first image with the second image.
At that moment, the print data are generated on condition that the
pixel density of the compensation range Ez is 200 dpi and the pixel
density of a print range Ew other than the compensation range Ez
is 67 dpi. After generation of the print data, print processing
is performed on the basis of the print data.
[0084]As mentioned above, the portion of the first image; namely,
the center portion of the first image which gains the high degree
of user's attention, is compensated with the second image that is
the telescopic image, and the thus-compensated first image is printed,
so that the area of high interest can be printed at high pixel density.
Consequently, even when the size of the print has been increased,
an output print which affords great satisfaction to the user can
be acquired. Meanwhile, the peripheral area other than the center
area is printed on the basis of the first image, and hence the pixel
density of the peripheral area is low. However, in many cases, the
user's attention paid to the peripheral area is low. Even when the
pixel density of the peripheral area is low, the user's satisfaction
is not greatly affected. Namely, in the present embodiment, even
when the print size is increased, an output print which affords
great satisfaction to the user can be obtained.
[0085]When the first image is printed after a portion of the first
image has been replaced with the second image, there may arise a
case where the user feels a sense of discomfort induced by discontinuity
between the items of data along the boundary area between the first
and second images. A weighted average between the pixel data pertaining
to the first image and the pixel data pertaining to the second image
may be obtained in connection with the periphery of the boundary
between the first and second images, to thus effect gradual transition
from the first image to the second image. As a distance from the
boundary line between the first and second images increases outwardly,
a weighting coefficient W1 of the first image is increased. Conversely,
as the distance increases inwardly with reference to the boundary
line, a weighting coefficient W2 of the second image is increased.
A weighted average Mave={(M1.W1)+(M2.W2)}/2 of the weighting coefficients
W1, W2; the pixel data M1 pertaining to the first image=(R1, G1,
B1); and the pixel data M2 pertaining to the second image=(R2, G2,
B2) are taken as pixel data for printing operation. In the periphery
of the boundary, gradual transition from the first image to the
second image is effected, whereby a natural printed image is obtained
and higher user satisfaction can be achieved.
[0086]As is evident from the above descriptions, in the present
embodiment, only when compensation using the second image is required,
data pertaining to the first image and data pertaining to the second
image are managed so that the second image can be used. Put another
way, the first image and the second image are stored and retained
in memory as separate items of image data. Consequently, when compared
with a case where an image formed from synthesis of the first and
second image is stored and retained, a required data size is significantly
reduced, and the user's satisfaction is more easily attained.
[0087]When an image formed from synthesis of the first and second
image is generated and stored, the first image must be interpolated
so as to match the number of pixels of the second image. Specifically,
it is assumed that the first and second images are equal in the
number of pixels and that magnifying power M is three. In this case,
in order to obtain an image formed from synthesis of the first and
second images, the figure range indicated by one pixel of the first
image must be matched with the figure range indicated by one pixel
of the second image. Before interpolation of pixels, one pixel of
the second image corresponds to one-ninth of one pixel of the first
image. Therefore, in order to synthesize the images, pixels must
be interpolated such that one pixel of the first image is increased
to nine pixels, as shown in FIG. 10. In FIG. 10, hatched squares
depict pixels P2 of the second image. Squares outlined by thick
lines depict pixels P1 of the first image. Unhatched squares outlined
with fine lines depict the pixels p1 of the first image acquired
before interpolation of the pixels. As shown in FIG. 10, in order
to synthesize the first and second images, each of the pixels P1
of the first image must be interpolated to nine pixels. When the
first image having undergone such pixel interpolation and the second
image are synthesized, the data size of resultant image data becomes
nine times as large as that of the first image achieved before pixel
interpolation, which in turn puts a squeeze on memory having finite
storage capacity.
[0088]In contrast, in the present embodiment, predetermined data
are embedded into the header of an image file so that compensation
can be performed by a second image only when required, and the first
and second images are preserved as separate items of data. Therefore,
an increase in the number of pixels, which would otherwise be caused
by pixel interpolation, is prevented, and no squeeze is put on memory
having limited storage capacity. Concurrently, since the images
are managed in such a manner that the first image can be compensated
with the second image as required, the user's satisfaction can also
be fulfilled. Consequently, there can be provided the digital camera
10 that on the whole affords high satisfaction to the user.
PARTS LIST
[0089]10 camera [0090]20 first image-capturing system [0091]21
first image-capturing lens system [0092]22 first image-capturing
element [0093]23 analogue image processing circuit [0094]24 AD conversion
circuit [0095]25 buffer memory [0096]26 signal processing sections
[0097]30 second image-capturing system [0098]31 second image-capturing
zoom lens [0099]32 second image-capturing element [0100]33 analogue
image processing circuit [0101]34 AD conversion circuit [0102]35
buffer memory [0103]36 signal processing sections [0104]40 multiplexer
[0105]50 CPU [0106]60 signal processor (S 1007) (S 1015) (S 1024)
(S 1026) [0107]62 buffer memory [0108]70 user memory (S 1010) (S
1029) [0109]80 liquid-crystal monitor (S 1009) (S 101 7) (S 1028)
[0110]90 operation section [0111]91 release button [0112]92 zoom
button [0113]93 cross-key pad [0114]94 switching lever (S1002) [0115]95
playback button [0116]100 control section [0117]110 strobe firing
section [0118]S1001 first release state [0119]S1003 operating state
[0120]S1004 incident light [0121]S1005 second release state [0122]S1006
image-capturing operation [0123]S1008 image and header date [0124]S1011
operating state [0125]S1012 zooming [0126]S1013 second release state
[0127]S1014 image-capturing operation [0128]S1016 image data and
header data [0129]S1018 memory [0130]S1020 operating state [0131]S1021
AF and zooming [0132]S1022 second release state [0133]S1023 image-capturing
operation [0134]S1025 image data and header data [0135]S1027 image
data and header data
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