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Digital Camera Patent Abstract
A digital camera includes a gyroscope for sensing an angle by which
the image sensing surface of the camera is tilted relative to the
horizontal direction. A system controller, when receiving the tilt
angle from the gyroscope, adds the tilt angle to image data temporarily
stored in an image memory, which is included in a signal processor,
in the form of tag information. A correcting circuit rotates the
image in the opposite direction by the tilt angle in accordance
with the tag information added to image data and causes a monitor
to display the resulting image. The digital camera thus produces
the image to be displayed in its adequate position without resorting
to any device for holding the camera in its adequate position.
Digital Camera Patent Claims
1. A digital camera comprising: an image sensor for picking up an
image, said image sensor comprising an image sensing surface on
which a plurality of photoelectric transducers are arranged; an
angle sensor for sensing an angle by which the image sensing surface
is rotated from a reference position in a first direction about
an optical axis perpendicular to the image sensing surface; and
an image correcting circuit for rotating the image picked up by
said image sensor in a second direction opposite to the first direction
by the angle sensed by said angle sensor to produce a corrected
digital image.
2. The digital camera in accordance with claim 1, wherein said
image correcting circuit rotates the digital image about a center
of the digital image.
3. The digital camera in accordance with claim 1, wherein said
image correcting circuit rotates the digital image about a desired
point of the digital image in the second direction.
4. The digital camera in accordance with claim 1, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and a background
inserting circuit for displaying a background color in a region
within the reproduction frame where an image to be displayed is
absent.
5. The digital camera in accordance with claim 4, wherein said
background inserting circuit selects the background color from a
color represented by pixels reproduced around the region where an
image to be displayed is absent.
6. The digital camera in accordance with claim 2, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and a background
inserting circuit for displaying a background color in a region
within the reproduction frame where an image to be displayed is
absent.
7. The digital camera in accordance with claim 3, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and a background
inserting circuit for displaying a background color in a region
within the reproduction frame where an image to be displayed is
absent.
8. The digital camera in accordance with claim 1, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and an image enlarging
circuit for enlarging the corrected digital image to a degree that
causes a region of the reproduction frame where an image would be
lost if the corrected digital image were displayed to disappear,
and causing said display to display a resulting enlarged digital
image.
9. The digital camera in accordance with claim 2, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and an image enlarging
circuit for enlarging the corrected digital image to a degree that
causes a region of the reproduction frame where an image would be
lost if the corrected digital image were displayed to disappear,
and causing said display to display a resulting enlarged digital
image.
10. The digital camera in accordance with claim 3, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and an image enlarging
circuit for enlarging the corrected digital image to a degree that
causes a region of the reproduction frame where an image would be
lost if the corrected digital image were displayed to disappear,
and causing said display to display a resulting enlarged digital
image.
11. The digital camera in accordance with claim 1, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and an image reducing
circuit for reducing the corrected digital image to a degree that
causes a region of the reproduction frame which would bulge out
from the reproduction frame if the corrected digital image were
displayed to enter the reproduction frame, and causing said display
to display a resulting reduced digital image.
12. The digital camera in accordance with claim 2, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and an image reducing
circuit for reducing the corrected digital image to a degree that
causes a region of the reproduction frame which would bulge out
from the reproduction frame if the corrected digital image were
displayed to enter the reproduction frame, and causing said display
to display a resulting reduced digital image.
13. The digital camera in accordance with claim 3, further comprising:
a display including a display screen having a reproduction frame
for displaying the digital image on the screen; and an image reducing
circuit for reducing the corrected digital image to a degree that
causes a region of the reproduction frame which would bulge out
from the reproduction frame if the corrected digital image were
displayed to enter the reproduction frame, and causing said display
to display a resulting reduced digital image.
Digital Camera Patent Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a digital camera for picking
up an image of a subject field to reproduce or display the image
picked up.
[0003] 2. Description of the Background Art
[0004] A digital camera is sometimes required to be held in an
adequate position when shooting a desired subject because, if the
position of the camera is not adequate, the subject is displayed
on its display monitor screen, which is usually rectangular, in
a tilted position with respect to the frame of the screen. The tilt
of a captured subject image displayed on the monitor screen is caused
when the camera is positioned with its reference direction, such
as either one of the edges of the imaging frame formed by its photosensitive
array, or image sensing surface, is not coincident with the actual
horizontal direction in the field including the intended subject.
In light of this, it has been customary to provide a digital camera
with a leveling function or mount the camera to a tripod in a horizontal
position.
[0005] Japanese patent laid-open publication No. 2004-145232, for
example, discloses a device for holding a camera, video camera or
similar image pickup apparatus. With the holding device taught in
this document, a person, operating the camera, hangs a strap from,
e.g., the top of trousers, a belt or the neck and inserts hook portions
formed at the lower end of the holding device into the strap. In
this condition, the person holds the camera by using the hook portions
as a fulcrum, so that a stable image is achievable even during walking.
[0006] However, the problem with the holding device stated above
is that the operator of the camera has to insert the hook portions
formed at the lower end of the holding portion into the strap by
troublesome operation. Moreover, it is awkward for the operator
to use such a holding device simply in order to shoot a desired
subject with the horizontal position maintained.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide a digital
camera for producing a subject image to be displayed in its adequate
position without resorting to any special holding device.
[0008] A digital camera of the present invention includes an image
sensor for picking up an image and having an image sensing surface
on which a plurality of photoelectric transducers are arranged.
An angle sensor senses an angle by which the image sensing surface
is rotated from a reference position in a first direction about
an optical axis perpendicular to the image sensing surface. An image
correcting circuit rotates a digital image picked up by the image
sensor in a second direction opposite to the first direction by
the angle sensed by the angle sensor to produce a corrected digital
image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The objects and features of the present invention will become
more apparent from consideration of the following detailed description
taken in conjunction with the accompanying drawings in which:
[0010] FIG. 1 is a schematic block diagram showing a preferred
embodiment of a digital camera in accordance with the present invention;
[0011] FIG. 2A shows a specific image picked up by the camera of
FIG. 1 held in a tilted position;
[0012] FIG. 2B conceptually shows the outline structure of the
camera in accordance with the illustrative embodiment shown in FIG.
1;
[0013] FIG. 3A shows a specific image picked up;
[0014] FIG. 3B corresponds to FIG. 3A, but shows an image corrected
by rotation unique to the illustrative embodiment;
[0015] FIG. 4A shows the image corrected by rotation;
[0016] FIG. 4B shows an image produced by enlarging the image shown
in FIG. 4A;
[0017] FIG. 5A shows the image corrected by rotation;
[0018] FIG. 5B shows an image produced by reducing the image shown
in FIG. 5A; and
[0019] FIG. 6 schematically shows a roll axis, a pitch axis and
a yaw axis about which the digital camera may be inadvertently rotated.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] Referring to FIG. 1 of the accompanying drawings, a digital
camera embodying the present invention, generally 10, includes an
optics 12, an image pickup section 14, a preprocessor 16, a signal
processor 18, a system controller 20, a control panel 22, a timing
signal generator 24, a driver 26, a video monitor or display 28,
a storage 30, an image correcting circuit 100 and a gyroscope or
angle sensor 104, which are interconnected as illustrated. It is
to be noted that part of the illustrative embodiment not directly
relevant to the understanding of the present invention is not shown,
and detailed description thereof will not be made in order to avoid
redundancy. The optics 12 includes a mechanical shutter, a lens
system, a zoom mechanism, an iris control mechanism and an automatic
focus (AF) control mechanism, although not shown specifically. The
optics 12 is configured to conduct light 13 incident from an imaging
field through the lens system to the image pickup section 14 with
its various mechanisms mentioned above controlled.
[0021] The zoom mechanism controls the angle of field while the
automatic focus mechanism drives a plurality of optical lenses to
focus a desired object. Motors, drivably connected to such mechanisms,
are driven by drive signals 32 output from the driver 26.
[0022] The iris control mechanism, having an automatic exposure
(AE) control function, includes a ring portion configured to rotate
in response to the drive signal 34 for varying the aperture of its
iris diagraph, although not shown specifically. The mechanical shutter
of the iris control mechanism may alternatively be included in the
lens system as a lens shutter, if desired.
[0023] The mechanical shutter prevents light from being incident
on the image pickup section 14 except the time of a shot, i.e.,
selectively opens or closes the shutter in response to the drive
signal 36 fed from the driver 26, thereby determining an exposure
period of time.
[0024] The image pickup section 14 includes an image sensor or
image sensing device 42 that includes an optical low-pass filter
38 and a color filter 40. The optical low-pass filter 38 filters
out the spatial frequency components of the incident light 13 above
the Nyquist frequency. The color filter 40 has its color filter
segments positioned in one-to-one correspondence to photosensitive
cells or photoelectric transducers, which are arranged on the image
sensor 42 to form an array, at the light incidence side of the image
sensor 42. The color filter 40 separates the color components of
the incident light 13 in accordance with the spectral characteristic
of the individual color filter segments.
[0025] The solid-state image sensor or photoelectric converting
device 42 has an array of photosensitive cells or photoelectric
transducers which are bidimensionally arranged on its image sensing
surface, as a plane substantially perpendicular to the optical axis
15 of, the optics 12, in the horizontal and vertical directions
in order to convert light 13 incident thereto to corresponding electric
signals. In the description, signals are designated by reference
numerals attached to signal lines on which they appear. As shown
in FIG. 1, to the image pickup section 14, drive signals 54 are
fed from the driver 26. Then drive signals 54 include a horizontal
and a vertical drive signal, an overflow drain (OFD) control signal
and so forth. The image pickup section 14 delivers an analog voltage
signal 56 output from the image sensor 42 to the preprocessor 16.
[0026] The preprocessor 16 includes a correlated-double sampling
(CDS) circuit for canceling noise, again-controlled amplifier (GCA)
and an analog-to-digital (A/D) converter, although not shown specifically.
The CDS circuit is fed from the timing signal generator 24 with
CDS pulses 72 in the form of sampling signal. The A/D converter
is fed with a conversion clock signal 74. The preprocessor 16 executes
noise cancellation, wave shaping and digitization and delivers all
data resultant from the processing to the signal processor 18 in
the form of digital data, or image data, 76.
[0027] The signal processor 18 includes an image memory 19 and
executes various image signal processing functions including gamma-correction,
synchronization, image conversion, compressing/expanding, input/output
interfacing, image display processing and image enlarging/reducing.
[0028] The image memory 19 of the signal processor 18 is generally
supplied with the digital image data 76 over a data bus 76 as an
image signal. The operation of the signal processor 18 is controlled
by a control signal 82 fed from the system controller 20 over a
control bus 82. The signal processor 18 is fed with timing signals,
not shown, from the timing signal generator 24. The timing signals
include a horizontal and a vertical synchronous signal.
[0029] The various functions of the signal processor 18 mentioned
earlier will be briefly described hereinafter. The gamma correction
function performs gamma correction on the image data fed from the
image memory 19 by use of data listed in a lookup table which the
signal processor contains.
[0030] The synchronization function executes interpolation on a
pixel of interest with colors not available with either one of the
actual and virtual pixels taken into account, thereby producing
all of the three primary colors at each pixel. Interpolation may
be effected by, e.g., multiplying the individual pixels by weighting
coefficients on the basis of a correlation between the pixel data,
adding the resulting products, and then producing a mean value of
the resulting sum. In this manner, three primary colors can be produced
for a pixel of interest at the same time. The term "synchronization"
is used in this sense. The image data thus synchronized are written
into the image memory 19.
[0031] The image converting function multiplies the synchronized
image data of three primary colors by a preselected coefficient
for thereby executing color-difference matrix processing.
[0032] The compressing/expanding function compresses image data
and color difference data fed thereto in a photo mode or a movie
mode by using the JPEG (Joint Photographic coding Experts Group)
standard, MPEG (Moving Picture coding Experts Group)-1 or MPEG-2
standard or similar standard. The input/output interfacing function
adjusts electric conditions and timing of the signals or data in
the event of writing or reading image data in or out of a card type
recording medium loaded on the storage 30. Image data 84 thus processed
by the input/output interface function are written into the storage
30. Further, the compressing/expanding function reads out image
data 84 from the storage 30 and then expands the image data 84 subjected
to input/output interface processing. It is to be noted that expansion
is opposite to compression in the same processing procedure or standard.
[0033] The image displaying function converts the image data generated
or image data (and color-difference data) expanded in the event
of reproduction to R (red), G (green) and B (blue) components of
image data and then formats the image data in a number of pixels
that can be displayed on the screen of the monitor 28. Image data
86 thus formatted are input to the monitor 28. The number of pixels
to be displayed, or the size of the monitor screen, is so selected
as to protect an image from defects ascribable to pixel skipping
or thinning out that would otherwise be caused.
[0034] The image memory 19 of the signal processor 18 receives
the digital data, i.e., image data 76 and temporarily stores the
data therein. Further, in the various kinds of processing stated
above, image data thus temporarily stored in the image memory 19
are read out from the image memory 19 and again written into the
memory 19 after processed. In an application where the same image
data are expected to be repeatedly read out from the image memory
19, the image memory 19 may preferably be implemented by a nonvolatile
memory device.
[0035] The system controller 20 is implemented by a microcomputer
or a CPU (Central Processing Unit) adapted to overall control the
common portions and digital processing portions of the camera 10.
The system controller 20 includes a ROM (Read Only Memory) storing
a program sequence of operation instructions. Further, the system
controller 20 controls the timing signal generator 24 and driver
26.
[0036] The system controller 20 receives a command signal 90 representative
of a mode selected or an operational trigger entered through the
control panel 22, and generates a control signal 92 in accordance
with the content of the command signal 90 to feed it to the timing
signal generator 24.
[0037] The system controller 20 takes account of line interpolation
to be executed by the signal processor 18, and control over a signal
generator and signal processing to also produce a control signal
82. Further, the system controller 20 also outputs a control signal
96 for writing and reading of image data to and from the storage
30 as well. In addition, the system controller 20 controls the operation
timing of the preprocessor 16, although not shown specifically.
[0038] The control panel 22 includes a shutter release button 23,
an enlarging/reducing key 25 for instructing enlargement and reduction
of a display image, a display image selector 27 for selecting and
deciding a display image device, and a correction commanding key
29 for commanding image correction. The control panel 22 is responsive
to the states of the shutter release button 23 and keys 25 through
29 to feed a command signal 90 to the system controller 20. The
control panel 22 may additionally be provided with a zoom select
key and direction keys, not shown, so that the operator of the camera
10 is allowed to use them to select desired one of the conditions
displayed on the monitor 28. The monitor 28 is equipped with a display
screen, not shown, having its reproduction frame 200, FIG. 3A, which
will be described later, and is generally implemented by a liquid
crystal display (LCD) panel. The role of the enlarging/reducing
key 25 may be assigned to the direction keys. In such a case, an
"up" key and a "down" key may be assigned to
enlargement and reduction functions, respectively, so as to allow
the operator to easily operate the control panel 22 as imagined.
[0039] The shutter release button 23 is implemented as a button
having two stepwise strokes or positions, e.g., the first stroke
or half-stroke position for conditioning the camera 10 for preliminary
image pickup and the second stroke or full-stroke position for conditioning
it for actual image pickup. The command signal 90 is representative
of the trigger timing indicative of the first and second strokes
also.
[0040] The correction commanding key 29 is adapted to indicate
that image correction should be executed on image data by rotation,
as will be described more specifically later. The display image
selector 27 is a key for feeding, when manipulated, the system controller
20 with the command signal 90 that causes the signal processor 18
to sequentially reads image data 82 stored in the storage 30 one
by one while displaying them on the monitor 28. The enlarging/reducing
key 25 serves as instructing enlargement or reduction of an image
being displayed on the monitor 28, as will also be described more
specifically later.
[0041] The timing signal generator 24 is adapted to generate various
timing signals from a reference or basic clock signal. The timing
signal includes a horizontal transfer signal, a vertical synchronous
signal, a horizontal synchronous signal, field shift pulses, a vertical
transfer signal and an electronic shutter pulse. In addition, the
timing signal generator 24 generates CDS pulses 72 and a conversion
clock signal 74 to deliver them to the preprocessor 16. The timing
signal generator 24 provides the driver 26 with the timing signals
98, including the vertical synchronous signal, horizontal synchronous
signal, field shift pulses, vertical transfer signal and electronic
shutter pulse.
[0042] The driver 26 includes a drive circuit for generating the
drive signals 32 through 36 and 54 in response to the timing signal
98 and control signal 94. More specifically, the driver 26 feeds
the drive signals 32, 34 and 36 to the lens system and iris control
mechanism included in the optics 12 for causing them to effect automatic
focus control and automatic exposure control. The driver 26 is operative
in accordance with the timing of an actual shot defined by the manipulation
on the shutter release button 23 of the control panel 22 to produce
the drive signal 36, causing the mechanical shutter to open and
then close.
[0043] The driver 26 also generates the drive signal 54 in response
to the timing signal 98 to feed the signal 54 to the image sensor
42 of the image pickup section 14. The drive signal 54 functions
as causing the image pickup section 14 to store signal charges in
the photo-sensitive areas of the individual photosensitive cells
or photoelectric transducers during an exposure period of time,
and subsequently causing the signal charges to be read out to the
vertical transfer paths and then transferred to the horizontal transfer
path to output the signal charges from the horizontal transfer path
in the form of an analog voltage signal 56 via an output amplifier.
[0044] The monitor 28 generally implemented by an LCD panel, as
mentioned earlier, includes a display controller, not shown, which
is adapted for visualizing the image data 86 fed from the image
memory 18 to display an image represented by the data on its display
screen. The LCD panel is equipped with an LCD controller, not shown,
which is configured to controllably apply a voltage to the LCD panel
so as to switch the orientation of liquid crystal molecules to thereby
display an image. Of course, the LCD panel may be replaced with
any other display unit so long as it is small in size and capable
of saving power.
[0045] The storage 30 is loaded with a semiconductor memory or
similar recording medium for storing therein the image data/tagged
image data 84 and data of background colors fed from the signal
processor 18. Tagged image data, as distinguished from the usual
image data, and background colors will be described specifically
later. The recording medium may, of course, be implemented by an
optical disk or a magneto-optical disk instead of a semiconductor
memory. The storage 30 selectively writes or reads the data in or
out of the recording medium by using a pickup or transducer, or
a combination of an optical pickup with a magnetic head matching
the recording medium to use. Writing and reading the data to and
from the storage 30 is executed by a control signal 96 fed from
the system controller 20.
[0046] The illustrative embodiment is specifically characterized
by the correcting circuit 100 and gyroscope 104 included in the
digital camera 10. Reference will be made to FIGS. 2 trough 6 for
describing the functions of the correcting circuit 100 and gyroscope
104 in detail.
[0047] The gyroscope 104 has two different degrees of freedom in
position. More specifically, as shown in FIG. 6, the camera 10 is
provided with the gyroscope 104 such that, when the camera 10 is
oriented with the image sensing surface, formed by the photosensitive
array of the camera 10, substantially parallel to the vertical direction,
the camera 10 has its optical axis 15, FIG. 1, substantially horizontal
so that the gyroscope 104 has its roll axis 205 extending substantially
in the direction of the optical axis 15, its horizontal pitch axis
210 substantially perpendicular to the roll axis 205 and its yaw
axis 220 substantially vertical. In that orientation, the gyroscope
104 is capable of sensing tilt angles of the camera about the roll
axis 205 and pitch axis 210. In the illustrative embodiment, the
position of the camera 10 is determined by the tilt angles of the
camera 10 about the two axes 205 and 210.
[0048] If desired, the gyroscope 104 with two degrees of freedom
may be replaced with a gyroscope with a single degree of freedom
because the present invention may sufficiently be implemented by
correcting the tilt angle about the roll axis 205. Further, because
the gyroscope 104 should only play the role of a sensor responsive
to the tilt angle about the roll axis 205, it may be replaced even
with an acceleration sensor, angle meter or similar inertia-based
device.
[0049] The solid-state image sensor 42 included in the image pickup
section 14, FIG. 1, has an array of photoelectric transducers or
cells, which are bidimensionally arranged in the horizontal and
vertical directions on its image sensing surface. As shown in FIG.
2B, let a vector 300a parallel to the image sensing surface, or
the array of photosensitive cells, of the image sensor 32 and extending
in parallel to the vertical transfer paths be referred to as a vertical-direction
position vector, and let another vector 300b parallel to the image
sensing surface and extending perpendicularly to the vertical transfer
paths be referred to as a horizontal-direction position vector.
The directions of the two vectors 300a and 300b vary in dependence
upon the position of the camera 10, but are always perpendicular
to each other.
[0050] Also conceptually shown in FIG. 2B is the rectangular monitor
screen of the monitor 28 mounted on the camera 10 and having its
short sides 302 and long sides 304. In FIG. 2B, assume that the
vertical-direction position vector 300a and horizontal-direction
position vector 300b are identical in direction with the short sides
302 and long sides 304, respectively.
[0051] While the gyroscope 104 is capable of sensing tilt angles
of the camera 10 about both of the roll axis 205 and pitch axis
210, the illustrative embodiment pays attention simply to the tilt
angle about the roll axis 205 as to the correction of an image.
More specifically, the embodiment aims at correcting the rotation
or tilt of the camera 10 occurring about its own optical axis. Stated
another way, when the camera 10 is tilted upward or downward about
the pitch axis 210 for shooting a desired subject, the camera 10
of the embodiment does not correct such an image.
[0052] As shown in FIG. 2A, when the camera 10 is tilted about
the roll axis 205 at the time of shooting a desired object, an image
viewed on the screen of the monitor 28 is tilted accordingly. The
embodiment corrects such a tilted image by rotating it. More specifically,
the camera 10 of the embodiment is adapted to rotate the image of
FIG. 2A tilted counterclockwise in the clockwise direction about
the roll axis 205 by an angle of .theta. with respect to a reference,
e.g., horizontal, direction 17. The resulting corrected image is
identical with an image which would have been picked up if the camera
10 were held in its adequate position, i.e., if the camera 10, actually
tilted, were operated with the image sensing surface of the image
sensor 40 rotated about the optical axis perpendicularly thereto
in order to position either the vertical-direction position vector
300a, FIG. 2B, or the horizontal-direction position vector 300b,
FIG. 2B, horizontal.
[0053] In the illustrative embodiment, the tilt angle .theta. is
selected to be 45 degrees or less. More specifically, one of the
vertical-direction and horizontal-direction position vectors 300a
and 300b, which is smaller in rotation angle up to the horizontal
when the camera 10 is rotated in the image sensing surface formed
by the photosensitive array is assumed to be the tilt angle .theta..
This is because the camera 10 is selectively held either horizontally
or vertically long in dependence on the field selectively snipped
by a horizontally long or a vertically long range. Thus, an image
is corrected such that the horizontal-direction position vector
300b becomes directed horizontally when the camera 10 is held horizontally
long, or the vertical-direction position vector 300a becomes directed
horizontally when the camera 10 is held vertically long.
[0054] FIG. 2B schematically shows the rotation angle .theta. in
a specific condition where in the camera 10 shot a subject in a
position tilted about the roll axis 205. In this case, a vertical-direction
vector 300 can be divided in component into the vertical-direction
and horizontal-direction position vectors 300a and 300b. Assuming
that the two vectors 300a and 300b have lengths of a and b, respectively,
then the rotation or tilt angle .theta. may be expressed as b/a=tan
.theta..
[0055] The system controller 20 serves as receiving a trigger timing
signal 90 sent from the control panel 22 in response to the shutter
release button 23 on the control panel 22 depressed by the second
stroke, i.e., to its full-stroke position for an actual shot, to
take in data representing an angle .theta. sensed by the gyroscope
104 over a signal line 102 and then send the data to the signal
processor 18 in the form of signal 82.
[0056] The signal processor 18 has the function of receiving the
signal 82 from the system controller 20 to add the angle .theta.
to the image data as tag information and then deliver the resulting
tagged image data 84 to the storage 30. The signal processor 18
is capable of reading the tagged image data 84 thus stored in the
storage 30 and sending them to the correcting circuit 100.
[0057] The correcting circuit 100 is adapted for receiving the
tagged image data 84 over a line 108, and detecting the angle .theta.
represented by tag information contained in the tagged image data.
If a subject 202 represented by the image data is detected to be
tilted, as shown in FIG. 3A by way of example, then the correcting
section 100 rotates the image or picture of the data counterclockwise
by the angle .theta. about the center of the pickup range by an
arithmetic operation, thereby correcting the image data as if the
image were picked up by the camera 10 substantially accurately held
in the horizontal or the vertical position, as shown in FIG. 3B.
The correcting circuit 100 then returns the corrected image data
to the signal processor 18 over the signal line 108. In regions
204, image data to be reproduced are absent while, in regions 206,
image data to be reproduced are present, but not contained in the
reproduction frame 200.
[0058] The camera 10 may be adapted, if desired, such that the
center of the rotation of an image of the data may be on any desired
point in a frame of image selected on the control panel 22 by the
operator of the camera 10. The correcting section 100, implemented
as an independent circuit, may alternatively be included in the
signal processor 18.
[0059] The signal processor 18 functions as filling the regions
204, FIG. 3B, where image data to be displayed after correction
are absent with one of the background colors stored in the storage
30. The signal processor 18 may be adapted to automatically select
as a background color a color which is identical with majority one
of the colors represented by the pixels reproduced or contained
around, or in the vicinity of, the regions 204, e.g., the edges
of the image. Alternatively, the camera 10 may be adapted such that
the operator of the camera 10 use the display image selector 27
of the operation panel 22 to reproduce the background colors and
any desired image stored in the storage 30 and then select and set
one of the background colors adequate for the image. The background
color thus selected by the operator is reproduced or visualized
in the regions 204.
[0060] The signal processor 18 is capable of enlarging or reducing
the image data instead of filling up the empty regions 204 within
the reproduction frame 200, FIG. 3B, with a background color. More
specifically, the signal processor 18 enlarges an image in order
to exclude the empty regions 204, or reduces an image in order to
reproduce or include regions 206 lost due to the rotation of the
image data in the reproduction frame 200.
[0061] While the enlargement and reduction of an image of the data
may be executed by any conventional method, image data appearing
on the monitor 28 or image data selected from image data stored
in the storage 30 may be enlarged or reduced by a method disclosed
in, e.g., Japanese patent laid-open publication No. 2004-288198
or 243218/1998. If desired, a plurality of different image data
selected may be enlarged or reduced at the same time. The operator
is capable of varying the magnification of enlargement or that of
reduction by operating the image data enlarging/reducing key 25
of the operation panel 22.
[0062] FIGS. 4A and 4B demonstrate how image data corrected by
rotation are enlarged specifically. As shown in FIG. 4A, image data
corrected by rotation are displayed as a visible image within the
reproduction frame 200, but there exist the regions 204 where image
data to be reproduced are absent and the regions 206 where image
data are present, but not contained in the reproduction frame 200.
In this case, the signal processor 18 may enlarge the image little
by little until all the regions 204 disappear, as shown in FIG.
4B, and then reproduce the final image, in which case the image
is reproduced within the entire reproduction frame 200.
[0063] FIGS. 5A and 5B show how image data corrected by rotation
are reduced specifically. FIG. 5A, like FIG. 4A, shows image data
corrected by rotation and reproduced in the reproduction frame 200.
When the image data shown in FIG. 5A should be reduced, the signal
processor 18 may reduce them little by little until the regions
206, not lying in the reproduction frame 200, entirely lie in the
reproduction frame 200, as shown in FIG. 5B, and then reproduce
the image, in which case the entire image picked up is reproduced
within the reproduction frame 200. At this instant, a desired background
color may be reproduced or visualized in the regions 204.
[0064] An alternative method of enlarging or reducing an image
of the data corrected by rotation will be described hereinafter.
The alternative method begins with a step of determining the number
of persons present or viewed in an image by use of a face image
separating procedure taught in Japanese patent laid-open publication
No. 2000-295574. If the number of persons is equal to or smaller
than a predetermined number, then the signal processor 18 enlarges
the image with a magnification that causes the regions 204 to be
excluded from the reproduction frame 200, as shown in FIG. 4B. Conversely,
if the number of persons is greater than the predetermined number,
then the signal processor 18 reduces the image data with a magnification
that causes even the regions 206 to be reproduced or included within
the reproduction frame 200, as shown in FIG. 5B. In the event of
reduction, the regions 204 may be filled with a desired background
color.
[0065] A specific operation of the digital camera 10 having the
above construction will be described hereinafter. As shown in FIGS.
2A and 2B, assume that the operator inadvertently holds the camera
10 in a position tilted by the angle .theta. when shooting a desired
subject 202. Then, when a pickup timing is reported from the shutter
release button 23 to the system controller 20, the system controller
20 sends a control signal 92 to the timing signal generator 24 and
a control signal 102 to the gyroscope 104 at the same time. In response
to the control signal 102, the gyroscope 104 senses the tilt angle
.theta.. The system controller 20 reads the tilt angle .theta. thus
sensed by the gyroscope 104 over the signal line 102 and then feeds
data of the tilt angle .theta. to the signal processor 18 as a signal
82.
[0066] On receiving the control signal 92, the timing signal generator
24 generates a timing signal 98 and feeds it to the driver 26. In
response, the driver 26 generates drive signals 32, 34, 36 and 54
based on the timing signal 98. The driver 26 delivers the drive
signals 32, 34 and 36 to the optical lens system and iris control
mechanism of the optics 12 in response to the control signal 94,
causing them to execute automatic focus and exposure control. Further,
the driver 26 sends the drive signal 36 to the mechanical shutter
for causing it to open and close. In addition, the driver 26 generates
the drive signal 54 in response to the timing signal 98 and sends
the drive signal 54 to the image sensor 42 included in the image
pickup section 14. The image sensor 42 produces an analog, imagewise
voltage signal 56 in response to the drive signal 54.
[0067] The preprocessor 16 executes noise cancellation, wave shaping
and digitization on the analog voltage signal 56 by using CDS pulses
72 and a conversion clock signal 74, which are fed from the timing
signal generator 24. The preprocessor 16 then sends all the processed
image data to the signal processor 18 as digital image data 76.
[0068] The signal processor 18 temporarily writes the digital data
76 in the image memory 19 thereof and then executes gamma conversion,
synchronization, image conversion, compression or expansion, input
interface processing and image display processing on the digital
data 76 in response to the control signal 82. As a result, the digital
data 76 are converted to image data 84. Further, when the control
signal 82 input to the signal processor 18 includes the data of
the tilt angle .theta., the signal processor 18 adds the data of
the angle .theta. to the image data as tag information and then
writes the resulting tagged image data 84 in the storage 30.
[0069] The operator of the camera 10 is capable of operating the
image selector 27 to watch a plurality of tagged images stored in
the storage 30 on the monitor 28 one by one. The operator may then
use the correction commanding key 29 in order to correct a desired
image viewed on the monitor 28. When a command indicative of the
correction of image data by rotation is output from the correction
commanding key 29, the control panel 22 generates a command signal
90 and sends it to the system controller 20. In response, the system
controller 20 sends a control signal 82 to the signal processor
18.
[0070] The signal processor 18, having received the control signal
82, sends the tagged image data representative of an image being
reproduced to the correcting circuit 100. In response, the correcting
circuit 100 detects the tilt angle .theta. out of the tagged image
data and then rotates the image of the tagged image data about the
center of the image by the angle .theta. in the opposite direction,
which is opposite to the direction in which the tilt angle 0 is
formed with respect to the reference direction 17. As a result the
image data are corrected as if they were picked up by the camera
10 substantially accurately held in the horizontal or the vertical
position. For example, the tilted image shown in FIG. 3A is rotated
by the angle .theta. indicated by the tag information in the opposite
direction, so that the corrected image shown in FIG. 3B is obtained.
The data of the image thus corrected by rotation are transferred
or returned from the correcting circuit 100 to the signal processor
18 and then displayed oh the monitor 28. At this instant, the regions
206 of the image not lying in the reproduction frame 100 are not
displayed.
[0071] The signal processor 18 fills the regions 204, FIG. 3B,
where image data to be displayed after corrected are absent with
one of the background colors stored in the storage 30. At this instant,
the signal processor 18 automatically selects a background color
identical with a color represented by most of the pixels reproduced
around, or in the immediate neighborhood of, the regions 204.
[0072] When the image data should be enlarged or reduced, a command
signal 90 indicative of enlargement or reduction of the image of
the data corrected or not corrected is sent from the enlarging/reducing
key 25 of the control panel 22 to the system controller 20. In response,
the system controller 20 sends a control signal 82 to the signal
processor 18 so as to cause the latter to enlarge or reduce the
image data to be viewed on the monitor 28 and again feeds them to
the monitor 28.
[0073] More specifically, in the case of enlargement, image data
corrected by rotation, as shown in FIG. 4A are displayed in the
reproduction frame 200, but there exist the regions 204 where image
data to be reproduced are absent and the regions 206 where image
data are present, but not contained in the reproduction frame 200.
In this case, the signal processor 18 may enlarge the image little
by little until all the regions 204 disappear from the frame 200,
as shown in FIG. 4B, and then reproduce the resultant image, in
which case the image is reproduced in, or occupies, the entire reproduction
frame 200.
[0074] On the other hand, in the case of reduction, image data
corrected by rotation are reproduced in the reproduction frame 200,
as shown in FIG. 5A. When the image of the data shown in FIG. 5A
should be reduced, the signal processor 18 may reduce the image
little by little until the regions 206, not lying in the reproduction
frame 200, entirely lie within the reproduction frame 200, as shown
in FIG. 5B, and then reproduce the resultant image, in which case
the entire image picked up is reproduced within the reproduction
frame 200. At this instant, a desired background color may be reproduced
in the regions 204.
[0075] The signal processor 18 delivers the image data corrected
by rotation, or enlarged or reduced, to the storage 30 over the
signal line 84.
[0076] In summary, it will be seen that the present invention provides
a digital camera capable of correcting an image after a shot for
thereby reproducing and displaying an adequate image. It is therefore
not necessary for the operator of the digital camera to care about
the position of the camera at the time of shooting. Thus, the present
invention is clearly distinguishable from conventional technologies
that correct the position of a camera by use of a holder or similar
exclusive apparatus before shooting.
[0077] The entire disclosure of Japanese patent application No.
2005-055517 filed on Mar. 1, 2005, including the specification,
claims, accompanying drawings and abstract of the disclosure is
incorporated herein by reference in its entirety.
[0078] While the present invention has been described with reference
to the particular illustrative embodiment, it is not to be restricted
by the embodiment. It is to be appreciated that those skilled in
the art can change or modify the embodiment without departing from
the scope and spirit of the present invention. |