Digital Camera Patent Abstract
On a screen G1 of a liquid crystal display, a digital camera displays
an AF cursor for use as a focusing point. Thus, a shooter shifts
the AF cursor to the portion of a subject to be focused, so as to
carry out the setting. Here, when the subject is zoomed up to an
enlarged screen G2 through an optical zooming operation, the AF
cursor is displayed on the enlarged screen G2, following the subject.
Moreover, in the case when the subject is electronically zoomed
up to an enlarged screen G3, the AF cursor is also displayed on
the enlarged screen G3, following the subject. Thus, even when a
zooming process is carried out, it is not necessary to adjust the
position of the AF cursor; thus, it becomes possible to improve
the operability of the digital camera. Digital Camera Patent Claims
What is claimed is:
1. A digital camera comprising: an image sensor for picking up
an image of a subject and for generating a subject image; a display
for displaying said subject image generated by said image sensor
on a screen; a specifying member for specifying a specific position
on said screen; a calorimetric circuit for carrying out calorimetric
calculations so as to adjust white balance of said subject image
independent of said specified position specified by said specifying
member; and an image-pickup controller for controlling an image-pickup
operation based upon said specified position specified by said specifying
member.
2. The digital camera according to claim 1, further comprising:
an optical image-pickup system; wherein said image-pickup controller
carries out a focusing operation of said optical image-pickup system
with respect to said specified position on said screen that has
been specified by said specifying member.
3. The digital camera according to claim 1, further comprising:
a photometric circuit for measuring subject luminance; wherein said
image-pickup controller carries out photometric calculations with
respect to said specified position on said screen specified by said
specifying member.
4. The digital camera according to claim 1, wherein said colorimetric
circuit carries out calorimetric calculations on an entire portion
of said subject image independent of said specified position specified
by said specifying member.
5. A digital camera according to claim 1, further comprising: an
altering member for altering magnification of said subject image
displayed on said display; and a first specified position controller
for maintaining a relationship between said subject and said specified
position independent of an alteration of magnification carried out
by said altering member.
6. The digital camera according to claim 5, further comprising:
an optical image-pickup system; wherein said image-pickup controller
carries out a focusing operation of said optical image-pickup system
with respect to said specified position on said screen that has
been specified by said specifying member.
7. The digital camera according to claim 6, wherein said optical
image-pickup system has a variable focal length and said altering
member alters a focal length of said optical image-pickup system.
8. The digital camera according to claim 6, wherein said altering
member alters said magnification by displaying in an enlarged manner
one portion of said subject image generated by said image sensor
on said screen of said display.
9. The digital camera according to claim 8 further comprising:
a cursor generator for generating a cursor corresponding to said
specified position specified by said specifying member, wherein
said display composes said cursor and said portion of said subject
image to display the resulting image on said screen.
10. The digital camera according to claim 6, further comprising:
a photometric circuit for carrying out a photometric operation with
respect to a photometric area based upon said specified position,
wherein in the case when said specified position is located at an
edge of said screen, said image-pickup controller shifts a center
of said photometric area in the center direction of said screen
from said specified position.
11. The digital camera according to claim 5, further comprising:
a photometric circuit for measuring subject luminance; wherein said
image-pickup controller carries out photometric calculations with
respect to said specified position on said screen specified by said
specifying member.
12. The digital camera according to claim 11, further comprising:
an optical image-pickup system having a variable focal length, wherein
said altering member alters a focal length of said optical image-pickup
system.
13. The digital camera according to claim 11, wherein said altering
member alters said magnification of said subject image by displaying
in an enlarged manner one portion of said subject image generated
by said image sensor on said screen of said display.
14. The digital camera according to claim 5, further comprising:
a second specified position controller for maintaining a relationship
between said screen and said specified position independent of an
alteration in said magnification by said altering member; and a
selector for selecting either said first specified position controller
or said second specified position controller.
15. The digital camera according to claim 14, wherein in the case
when said second specified position controller is selected by said
selector with said specified position being out of said screen of
said display by said alteration in said magnification by said altering
member, said second specified position controller shifts said specified
position to a predetermined position within said screen.
16. The digital camera according to claim 15, wherein said predetermined
position within said screen is on an edge of said screen or in a
vicinity of an edge of said screen.
17. A method of operating a digital camera comprising the steps
of: picking up an image of a subject; generating a subject image
based on said picked up image of said subject; displaying said generated
subject image on a screen; specifying a specific position on said
screen; carrying out colorimetric calculations so as to adjust white
balance of said subject image independent of said specified position;
and controlling an image-pickup operation based upon said specified
position.
18. An image taking apparatus, comprising: an image sensor for
picking up an image of a subject; a display for displaying an image
of a subject generated by the image sensor; an input mechanism for
permitting a user to designate a position on said display; a means
for changing a magnification of an image displayed on said display;
a processor; and a memory for storing instructions executable by
said processor, said instructions for enabling said processor to
control operations of said apparatus; wherein said instructions
executable by said processor include: executable instructions, responsive
to a user designation of a position on said display, for displaying
on said display an indication of said designated position; executable
instructions, responsive to a user command, for invoking one of
a first display designation magnification mode and a second display
designation magnification mode; executable instructions, operable
when said first display designation magnification mode is invoked,
for controlling the display of a magnified image of a subject on
said display and for controlling the display of an indication of
said designated position so that a location of said indication on
said display prior to magnification is maintained after magnification
in a same location relative to said display; executable instructions,
operable when said second display designation magnification mode
is invoked, for controlling the display of a magnified image of
a subject on said display and for controlling the display of an
indication of said designated position so that a location of said
indication on said display prior to magnification is maintained
after magnification in a same location relative to said image of
a subject; and executable instructions for controlling an image
pickup operation based on said designated position.
19. An image taking apparatus in accordance with claim 18, wherein
said instructions executable by said processor include: executable
instructions for performing photometric operations on an image of
a subject generated by the image sensor, said executable instructions
for performing photometric operations being configured in a first
photometric mode to perform photometric operations based on a portion
of said image corresponding to said designated position on said
display, said executable instructions for performing photometric
operations being configured in a second photometric mode to perform
photometric operations based on a portion of said image shifted
away from said designated position on said display.
Digital Camera Patent Description
This application is based on application No. 2001-3698 filed in
Japan, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital camera wherein a focusing
point, etc. can be specified.
2. Description of the Background Art
In conventional digital camera techniques, Japanese Patent Application
Laid-Open No. 3-187580/1991 has disclosed techniques in which the
shooter can desirably set AF and AE points with respect to a subject
so as to prevent a centered blanking image and problems with an
image taken with mixed subjects located closely and far apart from
the camera.
However, the above-mentioned camera is applicable to the case in
which a mono-focal point lens is used; however, in the case when
it is applied to the case in which a zooming operation is carried
out by a zoom lens or the case in which an electronic zooming operation
is carried out, the relationship among three factors, that is, the
subject, display screen and AF point, needs to be taken into consideration.
However, the above-mentioned description has not described anything
about this point.
With respect to other conventional techniques, Japanese Patent
Application Laid-Open No. 8-265630/1996 and Japanese Patent Application
Laid-Open No. 10-191132/1998 have disclosed a technique in which
AF and AE points are set through gazing line detection; however,
problems with this technique are the necessity of providing an exclusively-used
hardware for detecting the gazing line, the inapplicability in the
case when the shooter is wearing glasses and the necessity of calibration
for absorbing differences in individual persons; thus, at present,
this technique has not been put into practical use.
SUMMARY OF THE INVENTION
The present invention relates to a digital camera.
In accordance with the present invention, this digital camera is
provided with: an image sensor for picking up an image of a subject
and for generating a subject image; a display for displaying the
subject image generated by the image sensor on a screen; a specifying
member for specifying a specific position on the screen; an image-pickup
controller for controlling an image-pickup operation based upon
the specified position specified by the specifying member; an altering
member for altering magnification of the subject image displayed
on the display; and a first specified position controller for maintaining
the relationship between the subject and the specified position
independent of an alteration of magnification carried out by the
altering member. Therefore, this arrangement eliminates the necessity
of adjusting the specified position upon zooming, thereby making
it possible to improve the operability of the digital camera.
In a preferred embodiment of the present invention, this digital
camera is arranged so that in the case when the second specified
position controller is selected by the selector with the specified
position being out of the screen of the display by the alteration
in the magnification by the altering member, the second specified
position controller shifts the specified position to a predetermined
position within the screen. Therefore, it becomes possible to prevent
an unnatural situation with the specified position disappearing
from the display screen.
Thus, the object of the present invention is to provide a digital
camera that provides better operability in specifying factors such
as focusing point.
These and other objects, features, aspects and advantages of the
present invention will become more apparent from the following detailed
description of the present invention when taken in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a digital camera in accordance with a
first preferred embodiment of the present invention;
FIG. 2 is a back view of the digital camera;
FIG. 3 is a side view of the digital camera;
FIG. 4 is a bottom view of the digital camera;
FIG. 5 is a block diagram that shows an inner construction of the
digital camera;
FIG. 6 is a block diagram that shows a construction of an image
processing unit;
FIG. 7 is a drawing that shows a data arrangement in a memory card;
FIG. 8 is a drawing that explains a live-view display;
FIG. 9 is a partial block diagram of the digital camera;
FIG. 10 is a drawing that explains a photometric process in the
digital camera;
FIG. 11 is a drawing that explains the photometric process in the
digital camera;
FIG. 12 is a drawing that explains the photometric process in the
digital camera;
FIG. 13 is a drawing that explains white balance in the digital
camera;
FIG. 14 is a drawing that explains white balance in the digital
camera;
FIG. 15 is a drawing that explains a zooming operation in the digital
camera;
FIG. 16 is a transition diagram of states that shows basic operations
in the camera;
FIG. 17 is a drawing that explains a screen of LCD;
FIG. 18 is a drawing that explains a screen of LCD when optically
zoomed;
FIG. 19 is a drawing that explains a screen of LCD when electronically
zoomed;
FIG. 20 is a drawing that explains an enlarged screen display;
FIG. 21 is a drawing that explains an enlarged screen display;
FIG. 22 is a drawing that explains an enlarged screen display;
FIG. 23 is a drawing that explains an enlarged screen display;
FIG. 24 is a drawing that explains an enlarged screen display;
FIG. 25 is a drawing that explains an enlarged screen display;
FIG. 26 is a drawing that explains an enlarged screen display;
FIG. 27 is a drawing that explains a n enlarged screen display;
FIG. 28 is a drawing that shows a selected screen with respect
to AF cursor;
FIG. 29 is a drawing that explains operations of a digital camera
in accordance with a second preferred embodiment of the present
invention;
FIG. 30 is a drawing that explains an operation of the digital
camera;
FIG. 31 is a drawing that explains an operation of the digital
camera;
FIG. 32 is a drawing that explains an LCD screen when zoomed;
FIG. 33 is a drawing that explains an LCD screen when zoomed;
FIG. 34 is a drawing that explains an LCD screen when zoomed; and
FIG. 35 is a drawing that explains an LCD screen when zoomed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[First Preferred Embodiment]
<Essential Construction of Digital Camera>
FIGS. 1 through 4 are a front view, a rear face view, a side view
and a bottom view, which show a digital camera 1 in accordance with
the first preferred embodiment of the present invention, and FIG.
5 is a block diagram that shows the inner structure of the digital
camera 1.
As illustrated in FIG. 1, the digital camera 1 is constituted by
a box-shaped camera main body 2 and an image-pickup unit 3 (indicated
by thick lines in FIGS. 1, 2 and 4) having a rectangular parallelepiped
shape. The image pickup unit 3 is provided with a zoom lens 301
having a macro-function that is an image pickup lens, and a light-adjusting
sensor 305 for receiving reflected light of flash light from a subject
and an optical finder 31, in the same manner as a lens-shutter camera
using silver halide films (hereinafter, referred to as "silver
halide camera"). The zoom lens 301 is capable of zooming from
35 mm to 70 mm in the focal length in the case of conversion to
a silver halide camera using a 35-mm film.
Here, at a rear position of the zoom lens 301 inside the image
pickup unit 3, a CCD 303 (see FIG. 5), which is a CCD color area
sensor functioning as an image-pickup means, is provided, and this
CCD 303 serves as one portion of an image-pickup circuit 302.
As illustrated in FIG. 1, on the front face of the camera main
body 2, a grip portion 4 is placed on the left end portion, a built-in
flash 5 is placed on the upper portion in the center and a shutter
button 8 is placed on the upper surface.
As illustrated in FIG. 2, on the rear face of the camera main body
2, a LCD 10 for carrying out a monitor display (corresponding to
a view finder) for a pickup image and for carrying out a reproduction
display, etc., of recorded images are placed virtually in the center.
This LCD 10 has a display screen consisting of 400.times.300 pixels.
Moreover, below the LCD 10, a group of key switches 221 to 226 used
for operating the digital camera 1 and a power switch 227 are installed.
Here, the key switch 224 also serves as an enlarged display button,
the key switch 225 also serves as an AF cursor button for displaying
an AF cursor CR corresponding to a focused point on the LCD 10,
and the key switch 226 also serves as a menu button. On the left
side of the power switch 227, an LED 228 that is lit up when the
power switch is on and an LED 229 for displaying the fact that an
access is being made to a memory card are placed.
Moreover, on the rear face of the camera main body 2, a mode setting
switch 14 for switching modes among "image-pickup mode",
"reproduction mode" and "preference mode" is
placed (see FIG. 3). The image-pickup mode is a mode in which an
image-pickup operation is carried out, the reproduction mode is
a mode in which picked-up images recorded on a memory card are reproduced
and displayed on the LCD 10, and the preference mode is a mode in
which various settings are carried out by making selections among
displayed items (set items).
The mode setting switch 14 is a slide switch having three contacts,
and in FIG. 2, when this is set downward, the image-pickup mode
is set, when set in the middle, the reproduction mode is set, and
when set upward, the preference mode is set.
Moreover, on the right side of the camera rear face, quadruple
switch 230 is placed, and in the image-pickup mode, by pressing
buttons 231, 232, the focal length of the zoom lens 301 is changed
so that the zooming process for altering the zoom magnification
is carried out, and the manual exposure correcting process is carried
out by pressing buttons 233, 234.
As illustrated in FIG. 2, on the rear face of the image-pickup
unit 3, an LCD button 321 for turning on and off the LCD 10 and
a macro button 322 are placed. When the LCD button is pressed, the
LCD display is on/off switched. For example, in the case when an
image-pickup process is carried out by using only the optical finder
31, the LCD display is turned off in order to cut power consumption.
At the time of a macro image-pickup process, the macro button 322
is pressed so that an AF motor 308 (see FIG. 5) is driven so as
to make the zoom lens 301 ready for a macro image-pickup operation.
As illustrated in FIG. 3, a DC input terminal 235 is provided on
the side face of the camera main body 2.
As illustrated in FIG. 4, on the bottom face of the camera main
body 2, a battery housing chamber 18 and a card insertion chamber
17 (card slot section) are installed. A memory card 91, a modem
card 92 and the like are inserted in the card insertion chamber
17. The card insertion chamber 17 is freely opened and closed by
using a clam-shell-type lid 15.
An opening 15a is formed in the lid 15 so that when a modem card
92 is attached, a connector portion for modem card communication
is exposed to outside with the lid 15 being closed. Thus, even with
the lid 15 being closed, it is possible to make a connection to
an external device.
In the digital camera 1, by inserting four size AA batteries into
the battery housing chamber 18, a power-supply battery 236 (see
FIG. 5), formed by series-connecting these batteries, is used as
a power supply source. Of course, power may be supplied from an
adapter through a DC input terminal shown in FIG. 4.
Next, referring to FIG. 5, an explanation will be successively
given of the inner structure of the image-pickup unit 3.
The image-pickup circuit 302 carries out a photo-electric conversion
on a light image of a subject converged on the CCD 303 through the
zoom lens 301, by using the CCD 303, and outputs the image as image
signals (signals consisting of signal trains of pixel signals received
as light in the respective pixels) of color components, R(red),
G(green) and B(blue). Here, the CCD 303 has pixels of 1600.times.1200.
Here, since the digital camera 1 has a fixed diaphragm, the exposure
control in the image-pickup unit 3 is carried out by adjusting the
value of exposure of CCD 303 (charge storage time of CCD 303 corresponding
to the shutter speed). In the case when an appropriate shutter speed
cannot be set due to low luminance of a subject, the inappropriate
exposing process due to an insufficient exposure is corrected by
executing the level adjustment of the image signal released from
the CCD 303. In other words, at the time of low luminance, the exposure
control is carried out by combining the shutter speed and gain adjustment.
Here, the level adjustment of the image signal is carried out by
an AGC (auto gain control) circuit within a signal processing circuit
313 that will be described later. The photometric process in this
automatic exposure (AE) will be described later.
A timing generator 314 is a device in which based upon a clock
sent from the timing control circuit 202 inside the camera main
body 2, a driving control signal for the CCD 303 is generated. The
timing generator 314 generates clock signals such as a timing signal
for start/end of integration (that is, start/end of exposure) and
reading control signals of light-receiving signals from the respective
pixels (horizontal synchronous signal, vertical synchronous signal,
transfer signal, etc.), and outputs these to the CCD 303.
The signal processing circuit 313 carries out a predetermined analog
signal process on an image signal (analog signal) outputted from
the image-pickup circuit 302. The signal processing circuit 313,
which is not shown, is provided with a CDS (correlated double sampling)
circuit and an AGC circuit inside thereof, reduces noise from the
image signal by the CDS circuit, and adjust the gain of the AGC
circuit so that the image signal is level-adjusted.
The light-adjusting circuit 304 controls the amount of light emission
of the built-in flash 5 at the time of a flash image-pickup operation
to a predetermined amount of light emission that is set by an entire-system
control unit 211 of the camera main body 2. In the case of the flash
image-pickup operation, simultaneously with the start of exposure,
reflected light of the flash light from the subject is received
by the light-adjusting sensor 305, and when this amount of received
light has reached a predetermined amount of light emission, the
light-adjusting circuit 304 outputs a flashing stop signal to a
flash control circuit 214 of the camera main body 2 through the
entire-system control unit 211. In response to this flashing stop
signal, the flash control circuit 214 forcefully stops the flashing
of the built-in flash 5, thereby controlling the amount of light
emission of the built-in flash 5 to a predetermined amount of light
emission.
Moreover, a zoom monitor 307 for altering the zoom ratio of the
zoom lens 301 and for shifting the lens between its housing position
and an image pickup position and an AF (auto focus) motor 308 for
carrying out a focusing operation are installed inside the image-pickup
unit 3.
Next, an explanation will be given of the inner structure of the
camera main body 2.
The entire-system control unit 211, which is mainly constituted
by a CPU, controls the driving operations of respective peripheral
constructions inside the above-mentioned image-pickup unit 3 and
the camera main body 2 that are connected by address buses, data
buses and control buses so that it systematically controls the image-pickup
operations of the digital camera 1.
Here, for convenience of explanation, a flow of image data in FIG.
5 (and FIG. 6 that will be described later) is indicated by arrows
between the peripheral constructions; however, in fact, the image
data is sent to each of the peripheral constructions through the
entire-system control unit 211. Moreover, inside the entire-system
control unit 211, a work RAM 211 a constituted by a DRAM and a flash
ROM 211b for storing programs are installed.
Next, an explanation will be given of a construction for processing
image signals and for displaying images inside the camera main body
2.
An analog image signal, sent from the signal processing circuit
313 of the image-pickup unit 3, is subjected to various image processes
in an image processing unit 200 inside the camera main body 2. FIG.
6 is a block diagram that shows the construction of the image processing
unit 200. First, an analog image signal sent to the image processing
unit 200 is converted to a digital signal of 10 bits for each pixel
in an A/D converter 205. Based upon a clock for A/D conversion inputted
from the timing control circuit 202, the A/D converter 205 converts
each pixel signal (analog signal) to a digital signal of 10 bits.
Here, the timing control circuit 202, controlled by the entire-system
control unit 211, is allowed to generate a reference clock and clocks
for a timing generator 314 and the A/D converter 205.
A black-level correction circuit 206 corrects the black level of
a pixel signal that has been A/D converted (hereinafter, referred
to as "pixel data"), to a reference black level. Moreover,
a WB circuit 207, which carries out a level conversion on pixel
data of each of color components, R, G, B, executes an automatic
adjusting (AWB) operation of white balance in which .gamma.-correction,
which will be executed in a succeeding process, is taken into consideration.
The white balance adjustment is carried out based upon a level conversion
table (more exactly, the data thereof) that is inputted to the WB
circuit 207 from the entire-system control unit 211, and the conversion
coefficient (gradient of the characteristic) of each of the color
components on the level conversion table is set for each picked-up
image by the entire-system control unit 211. The adjustment of the
white balance will be described later in detail.
A .gamma.-correction circuit 208 is used for correcting the .gamma.-characteristic
of image data. The output from the .gamma.-correction circuit 208
is sent to an image memory 209 as illustrated in FIG. 5.
The image memory 209 is a memory for storing pixel data outputted
from the image processing unit 200, and has a storage capacity corresponding
to one frame. In other words, in the case when the CCD 303 has pixels
arranged in a matrix format of 1600.times.1200, the image memory
209 has a storage capacity of pixel data corresponding to 1600.times.1200
pixels, and respective pixel data are stored in the corresponding
storage areas (addresses).
A VRAM 210 is a buffer memory for image data that is to be reproduced
and displayed on the LCD 10. The VRAM 210 has a storage capacity
of image data corresponding to 400.times.300 pixels of LCD 10, that
is, a capacity corresponding to 400.times.300 pixels.
With this arrangement, at the time of an image-pickup stand-by
state in the image-pickup mode, respective pixel data of images
that have been picked up by the image-pickup unit 3 with predetermined
intervals are processed by the image-processing unit 200, and stored
in the image memory 209, and also transferred to the VRAM 210 through
the entire-system control unit 211, and displayed on the LCD 10.
Thus, an image of a subject prior to an image-pickup operation is
displayed on the LCD 10 in a manner of moving-picture images, that
is, a live view display is carried out.
In other words, as illustrated in FIG. 8, in the live view display,
image data within the image memory 209 of 1600.times.1200 pixels
are thinned longitudinally as well as laterally to 1/4, and transferred
to the VRAM 210 having 400.times.300 pixels. Moreover, when the
enlarged display button 224 is depressed at this time, the image
data corresponding to 400.times.300 pixels within the image memory
209 are cut out, and transferred to the VRAM 210, thereby making
it possible to provide an enlarged display of 4 times in longitudinal
and lateral directions.
In this manner, the depression of the enlarged display button 224
allows the shooter to easily switch the picked up image currently
given by the CCD 303 to its enlarged image on the LCD 10.
Moreover, in the reproduction mode, after an image read from the
memory card 91 has been subjected to a predetermined signal processing
by the entire-system control unit 211, the resulting image is transferred
to the VRAM 210, and reproduced and displayed on the LCD 10. Here,
upon displaying an image on the LCD 10, a back light 16 is turned
on by the control of the entire-system control unit 211.
Next, an explanation will be successively given of the other constructions
inside the camera main body 2.
A card I/F 212 is an interface for passing and receiving signals
to and from various functional cards inserted to the card insertion
chamber 17. More specifically, image data is written on the memory
card 91 or image data is read therefrom, and data input-output operations
of the digital camera 1 are carried out to and from an external
device through a modem card 92.
As described earlier, the flash control circuit 214 is a circuit
for controlling flash light of the built-in flash 5. Based upon
the control signal from the entire-system control unit 211, the
flash control circuit 214 carries out controlling operations as
to the presence or absence of flash light, the amount of light emission,
the timing of light emission, etc. of the built-in flash 5, and
based upon the flashing stop signal inputted from the light adjusting
circuit 304, controls the amount of light emission of the built-in
flash 5.
A clock circuit 219 is a time-counting circuit for managing the
time and date of an image-pickup operation. This is driven by another
power supply, not shown.
Moreover, a zoom motor driving circuit 215 and the AF motor driving
circuit 216 for driving the zoom motor 307 and the AF motor 308
are installed inside the camera main body 2. These circuits carry
out functions in response to the operations on the operation unit
250 given through the shutter button 8 and the other various switches
and buttons.
For example, the shutter button 8 is a two-step switch that can
detect a half-pressed state (S1) and a full-pressed state (S2),
as is adopted in the silver halide camera, and when the shutter
button 8 is half-pressed in the stand-by state, the AF motor driving
circuit 216 drives the AF motor 308 so that the zoom lens 301 is
shifted to a focusing position.
Moreover, when the buttons 231, 232 are pressed, signals from these
buttons are sent to the entire-system control unit 211 so that based
upon an instruction from the entire-system control unit 211, the
zoom motor driving circuit 215 drives the zoom motor 307 so as to
shift the zoom lens, thereby carrying out an optical zooming operation.
The above-mentioned description has discussed the respective constructions
inside the camera main body 2; and in addition to data passing and
receiving processes to and from the peripheral constructions and
timing controls, the entire-system control unit 211 carries out
various other functions on a software basis.
For example, the entire-system control unit 211 is provided with
a luminance determining function and a shutter-speed setting function
for setting an exposure control value (shutter speed). The luminance
determining function refers to a function in which in the image-pickup
stand-by state, by utilizing images that have been acquired by the
CCD 303 every 1/30 second, and stored in the image memory 209, the
luminance of a subject is determined. The shutter-speed setting
function refers to a function in which, based upon the result of
determination as to the luminance of the subject by the luminance
determination, the shutter speed (integral action time of CCD 303)
is set.
Moreover, the entire-system control unit 211 is provided with a
filtering process function, a recording image generating function
and a reproduced image generating function so as to carry out recording
processes on picked-up images.
The filtering process function refers to a function in which high-frequency
components of an image to be recorded are corrected by a digital
filter so as to carry out an image-quality correction relating to
the outline portions.
The recording image generating function refers to a function in
which image data is read out from the image memory 209 so as to
generate a thumb-nail image and a compressed image to be recorded
in the memory card 91. More specifically, while scanning the image
memory 209 in a raster scanning direction, pixel data is read out
every 8 image pixels in the respective lateral and longitudinal
directions, and successively transferred to the memory card 91 so
that, while generating a thumb nail image, this is also recorded
in the memory card 91. Moreover, upon recording compressed image
data onto the memory card 91, all the pixel data are read out from
the image memory 209, and after these image data have been subjected
to a 2-dimensional DCT conversion, these are also subjected to a
predetermined compressing process by a JPEG system such as Huffman
coding process, etc., and then recorded on the memory card 91.
With respect to specific operations, in the image-pickup mode,
when the shutter button 8 gives an instruction to pick up an image,
after the instruction to pick up the image, a thumb nail image of
the image taken in the image memory 209 and a compressed image compressed
by the JPEG system based on a set compressing rate are generated,
and both of the images are stored in the memory card 91 together
with tag information relating to the picked-up image (information
such as frame numbers, exposure value, shutter speed, compressing
rate, the date of the image-pickup, data relating to on/off of flash
at the time of the image pickup, scene information and the results
of image determination). Here, the data format of the recording
image will be described later.
Moreover, the reproduced image generating function is a function
for data-decompressing a compressed image recorded in a memory card
to generate a reproduced image. With respect to specific operations,
when the mode setting switch 14 is set to a reproduction mode, the
image data having the greatest frame number within the memory card
is read out and subjected to data-decompression, and the resulting
data is transferred to the VRAM 210. Thus, the image having the
greatest frame number, that is, the image that was picked up most
recently, is displayed on the LCD 10.
FIG. 7 is a drawing that shows a data arrangement in a memory card
91. This memory card 91 functions as a recording medium for mainly
recording picked-up image data. As illustrated in FIG. 7, in the
memory card 91, respective frames of images, recorded by the digital
camera 1, are stored in a manner so as to be successively aligned.
Moreover, each frame has tag information TG, high-resolution image
data HD ((1600.times.1200) pixels) compressed by JPEG format and
thumb nail image data SD ((80.times.60) pixels) used for thumb nail
display, which are recorded therein. Moreover, the image data capacity
corresponding to one frame is set to approximately 1 MB. Furthermore,
this digital camera is allowed to also record sound files by inserting
a sound card. Thus, link information (the leading address of the
stored area) to the sound file is written in the tag TG of the image
file so that the sound file SF is stored on the address indicated
by the link information and thereafter.
<Concerning AF>
In the digital camera 1, an AF cursor corresponding to the AF area
is displayed on the LCD 10, and the following description will discuss
this area.
FIG. 9 is a block diagram that partially shows the digital camera
1.
The entire-system control unit 211 is provided with a cursor generation
unit 211f, a cursor display position control unit 211g, a resolution
conversion unit 211h, an image composing unit 211i, a focusing area
setting unit 211j and an evaluation value calculation unit 211k.
In the LCD 10, the cursor generation unit 211f reads out cursor
data from the flash ROM 211b so as to generate an AF cursor CR shown
in FIG. 15, and transfers it to a cursor display position control
unit 211g. Here, the cursor CR has a cross shape, and its size is
set to 16.times.16 pixels on the LCD 10.
Based upon an operation input on the operation unit 250 by the
shooter, the cursor display position control unit 211g alters the
display position of the AF cursor CR on the LCD 10.
As described earlier, in the normal display state, the resolution
conversion unit 211h sends image data formed by thinning image data
acquired by the CCD 303 into 1/4 to the image composing unit 211i,
and in the enlarged display state, it transfers one portion of image
data acquired by the CCD 303 to the image composing unit 211i, as
it is.
In the image composing unit 211i, the image inputted from the resolution
conversion unit 211h and the image of the AF cursor inputted from
the cursor display position control unit 211g are composed, and
transmitted to the VRAM 210. This composing operation makes the
size of the AF cursor CR on the LCD 10 set to a constant size independent
of the thinning rate in the resolution conversion unit 211h. This
is also true for the case of the electronic zooming process.
The focusing area setting unit 211j sets an AF area AR that is
utilized for focusing in accordance with the AF cursor CR on the
screen of the LCD 10.
The evaluation value calculation unit 211k carries out an evaluation
value calculating operation so as to carry out an AF operation in
a contrast method, in the case when the shutter button 8 is in a
half-pressed state (S1). In this case, with respect to the picked-up
image data corresponding to the AF area AR which will be described
later, the evaluation value is calculated as the sum of the absolute
values of differences in the adjacent pixels. Then, the lens is
driven, and the lens position having the highest evaluation value
is set as a focusing position. Therefore, the zoom lens 301 is driven
with respect to the AF area AR corresponding to the focusing point
so as to carry out the focusing operation; thus, it is possible
to bring a target main subject, etc. into focus.
<Concerning AE>
With respect to AE, based upon the position of the AF cursor CR
on the screen of the LCD 10, an AE operation is carried out based
upon the center-weighted photometry. In other words, the AF cursor
CR also functions as the AE cursor corresponding to the photometric
point.
As illustrated in FIG. 10, in this photometric process, an ellipse
Ea and an ellipse Eb serving as photometric areas are set centered
on the AF cursor CR, and the inside of the ellipse Ea is set as,
for example, a weighting coefficient 8, while the area from the
ellipse Ea to the ellipse Eb is set as, for example, a weighting
coefficient 2; thus, with respect to the image data acquired by
the CCD 303, photometric calculations are carried out. Thus, an
appropriate photometric operation aiming at the main subject is
executed.
Here, for example, in the case when the main subject is located
at the end of the screen, while the AF cursor CR is located at the
edge of the screen as illustrated in FIG. 11, if the ellipses Ea
and Eb using for the photometric operation are set centered on the
AF cursor CR, one portion of the ellipses Ea, Eb is located out
of the screen, the photometric operation has degradation in its
balance.
Therefore, as illustrated in FIG. 12, a limited area IG having
a short rectangular shape is set in the center of the screen, and
if the center of the AF cursor CR is located out of this limited
area IG, the center of the ellipse Ea is shifted to the end of the
limited area IG, while the ellipse Eb is shifted so as to contact
the edge of the screen EG. In this manner, by shifting the center
of the photometric area in the center direction of the screen from
the AF cursor CR, it becomes possible to carry out a well-balanced
photometric operation. Then, by using the results of this photometric
operation, it is possible to carry out an appropriate exposing control
operation.
<Concerning AWB>
The following description will discuss AWB more specifically.
As illustrated in FIG. 13, the image data within the screen memory
209 is divided into blocks of 16.times.12, each having a size corresponding
to 100.times.100 pixels.
Next, the respective pixel values of RGB are accumulated for each
block, and these are set to Rbij, Gbij, Bbij (1.ltoreq.i.ltoreq.12,
1.ltoreq.j .ltoreq.16). Then, as shown in the following equations
(1) to (3), the sums of these blocks are respectively calculated
and the values are represented by Rs, Gs and Bs. Then, as indicated
by equation (4), Gs/Rs and Gs/Bs are found to set (gr, gb). ##EQU1##
Next in the digital camera 1, depending on set conditions of white
balance, such as incandescent lamp and daylight, (gr, gb) can be
corrected.
For example, as illustrated in FIG. 14, an area Ra related to incandescent
lamp and an area Rb related to daylight are set, and (gr, gb) are
shifted to the closest points to each of these areas. Here, in the
case when (gr, gb) are located within each of the set areas, the
values, as it is, are used. The white balance control value thus
shifted are set as (grw, gbw), and by using these (grw, gbw), the
values of RGB, (Rw, Gw, Bw)=(G/grw, G, G/gbw), are calculated; thus,
by reflecting these values to the image data, the adjustment of
white balance is carried out.
<Operation of Digital Camera 1>
The following description will discuss the operation of the digital
camera 1. This operation is automatically carried out by the entire-system
control unit 211.
First, an explanation will be given of a zoom operation in the
digital camera 1.
FIG. 15 is a drawing that explains the zoom operation in the digital
camera 1.
A screen G1 shows a state of a subject OB that is displayed on
the LCD 10 in the case of a view angle with a focal length of 35
mm (converted to the case of 135) in the zoom lens 301.
Different from the screen G1 in the focal length, a screen G2 shows
a state of the subject OB that is displayed on the LCD 10 in the
case of a view angle with a focal length of 70 mm (converted to
the case of 135) in the zoom lens 301. The screens G1, G2 are switched
to each other by the operation of buttons 231, 232.
A screen G3 shows a state in which a subject is enlarged to double
the size by an electronic zooming operation. In this electronic
zooming operation, for example, the original image data having 1600.times.1200
pixels, acquired by the CCD 303, is trimmed to have 800.times.600
pixels, and recorded. In this case, the data corresponding to 800.times.600
pixels are thinned to 1/2, and displayed on the LCD 10.
In these alterations in the zooming magnification, the image is
enlarged centered on the center Oc of the screen.
Moreover, in the respective screens G1 to G3, the AF cursor CR
corresponding to the AF area AR is displayed by the depression of
the AF cursor button 225.
FIG. 16 is a drawing that shows state transitions in a basic operation
of the digital camera 1.
At state ST1, a live view display is given on the LCD 10, with
the AF area AR being set in the center of the screen of the LCD
10 without displaying the AF cursor CR. Here, when the shutter button
8 is half-pressed (S1), the sequence proceeds to state ST2, and
when the shutter button 8 is fully pressed (S2), the sequence proceeds
to state ST3. Moreover, when the enlarged display button 224 is
pressed, the sequence proceeds to state ST4, and when the AF cursor
button 225 is pressed, the sequence proceeds to state ST6.
At state ST2, the AF and AE operations are carried out in the center
of the screen of the LCD 10 while the AWB operation is carried out
on the entire screen. Here, in this case, the entire screen represents
not the entire display screen, but the entire image-pickup area.
In the case when the shutter button 8 is released from the half-pressed
state (S1), the sequence returns to state ST1.
At state ST3, picked-up image data is recorded in the memory card
91.
At state ST4, the subject OB is displayed in an enlarged manner
centered on the center of the screen of the LCD 10. In this state
also, in the same manner as state ST1, the AF area AR is set in
the center of the screen with no AF cursor CR being displayed. In
this case, when the shutter button 8 is half-pressed (S1), the sequence
proceeds to state ST5, and when the shutter button 8 is fully pressed
(S2), the sequence proceeds to state ST3. Moreover, when the enlarged
display button 224 is pressed, the sequence proceeds to state ST1,
and when the AF cursor button 225 is pressed, the sequence proceeds
to state ST9.
At state ST5, in the same manner as state ST2, the AF and AE operations
are carried out in the center of the screen of the LCD 10, and the
AWB operation is carried out on the entire screen. Here, in the
case when the shutter button 8 is released from the half-pressed
state (S1), the sequence returns to state ST4.
As illustrated in FIG. 17, at state ST6, the live view display
related to the subject OB is carried out on the LCD 10, and the
AF cursor CR is displayed on the screen of the LCD 10. Here, the
center of the AF area AR is coincident with the center of the AF
cursor CR.
In this case, when the shutter button 8 is half-pressed (S1), the
sequence proceeds to state ST7, and when the shutter button 8 is
fully pressed (S2), the sequence proceeds to state ST3. Moreover,
the enlarged display button 224 is pressed, the sequence proceeds
to state ST9, and when the AF cursor button 225 is pressed, the
sequence proceeds to state ST1. Moreover, when the crossed switches
230 are operated, the sequence proceeds to state ST8.
At state ST6, in the case when the shooter specifies a zooming
operation in which screen Gi shown in FIG. 15 is optically zoomed
to screen G2, the subject OB is displayed on the LCD 10 as illustrated
in FIG. 18. In this screen G2, the AF cursor CR is displayed while
being held in the same position with the same size as screen G1.
Moreover, in the case when the shooter specifies an electronic
zooming operation in which the screen is zoomed to screen G3 shown
in FIG. 19, the subject OB is displayed on the LCD 10 as illustrated
in FIG. 19. In this screen G3 also, the AF cursor CR is displayed
while being held in the same position with the same size as screens
G1, G2.
In this manner, even when the zooming operation is carried out,
since the position of the cursor CR is unchanged on the screen,
the shooter is free from incongruous feelings in visibility, thereby
making it possible to improve the operability of the digital camera
1.
At state ST7, the AF and AE operations are carried out at the AF
cursor CR position on the screen of the LCD 10, the AWB operation
is carried out on the entire screen independent of the position
of the AF cursor CR. Here, in the case when the shutter button 8
is released from the half-pressed state (S1), the sequence returns
to state ST6.
At state ST8, the AF cursor CR is shifted in the horizontal and
vertical directions through the input operations in the crossed
switches 230 by the shooter so that the focusing point is altered.
Here, upon completion of the operation of the crossed switches 230,
the sequence proceeds to state ST6.
At state ST9, an enlarged display area Au (FIG. 20), centered on
the AF cursor CR, is displayed in an enlarged manner on the screen
of the LCD 10, as illustrated in FIG. 21. This enlarged display
area Au is set as an area having a short rectangular shape centered
on the AF cursor CR, which includes the AF cursor CR. In this case,
as illustrated in FIG. 9, since the cursor and the displayed image
are composed in the image composing unit 211i, the size of the AF
cursor CR is displayed in the same size as the size prior to the
enlargement.
At this state ST9, for example, as illustrated in FIG. 22, in the
case when the AF cursor CR is located at the edge of the screen
with the enlarged display area Au set centered on the AF cursor
CR, since there is a portion sticking out from the screen, that
is, an area Ap (portion indicated by parallel slanted lines) other
than the image acquired by the CCD 303, the left portion Aq (portion
indicated by parallel slanted lines) of the enlarged display screen
corresponding this area Ap is displayed in a specific color such
as a blue back area as illustrated in FIG. 23. Thus, it becomes
possible to clearly indicate that there is an area that cannot be
displayed by the enlarged display screen.
In this state ST9, when the shutter button 8 is half-pressed (S1),
the sequence proceeds to state ST10, and when the shutter button
8 is fully pressed (S2), the sequence proceeds to state ST3. Moreover,
when the enlarged display button 224 is pressed, the sequence proceeds
to state ST6, and when the crossed switches 230 are operated, the
sequence proceeds to state ST11.
At state ST10, the AF and AE operations are carried out at the
AF cursor CR position on the screen of the LCD 10, and the AWB operation
is carried out on the entire screen independent of the position
of the AF cursor CR. In this manner, since the AF operation is carried
out in response to the directive input operation of the shutter
button 8 in a state where the enlarged display is operative, it
is possible to confirm the result of a focusing operation while
viewing the subject in detail. Here, when the shutter button 8 is
released from the half-pressed state (S1), the sequence proceeds
to state ST9.
At state ST11, the AF cursor CR is shifted in the horizontal and
vertical directions by the operation of the crossed switches 230
carried out by the shooter. In this case, the shift of the AF cursor
CR is limited to the inside of the screen. In the case when the
AF cursor CR reaches the end of the screen, the enlarged display
area Au related to the subject may be shifted and displayed in a
manner so as to follow the AF cursor in its shifting direction.
Upon completion of the crossed switches 230, the sequence proceeds
to state ST9.
The above-mentioned operations of the digital camera 1 make it
possible to improve the operability in specifying processes of items,
such as the AF cursor.
Here, at step ST9 as described above, the enlarged display screen
may be displayed as described below.
In the case when the enlarged display area Au is determined, centered
on the AF cursor CR, if this area sticks out of the screen, the
enlarged display area may be set in a manner so as not to be centered
on the AF cursor CR, but to allow the end of the enlarged display
area Au to coincide with the end of a picked-up image, as illustrated
in FIG. 24. Thus, an enlarged display as shown in FIG. 25 is given,
making it possible to eliminate the necessity of displaying the
non-displayable portion in a specific color.
Moreover, in the case when an enlarged display is given from the
screen that has been zoomed up by the electronic zooming operation,
if the enlarged display area Au is set centered on the AF cursor
CR as illustrated in FIG. 26, a portion Ap sticking out of the display
screen appears; however, by utilizing the original image data acquired
by the CCD 303 prior to the trimming process by the electronic zooming
operation, the image data of the sticking-out portion Ap is interpolated
so that as illustrated in FIG. 27, the portion Ar corresponding
to the area Ap shown in FIG. 26 can be displayed on the screen.
Consequently, even in the case when the AF cursor CR is positioned
at the end of the screen, the AF cursor CR is displayed in the center
of the enlarged display screen, thereby making it possible to improve
the visibility.
<Second Preferred Embodiment>
A digital camera 1A according to the second preferred embodiment
has a construction similar to that of the digital camera 1 in the
first preferred embodiment; however, it is different in the construction
of an entire-system control unit 211A that executes the operations
described below.
<Operation of Digital Camera 1A>
A digital camera 1A carries out the same operations as the digital
camera 1 in the first preferred embodiment that has explained by
reference to FIG. 16, and an operation, which allows the AF cursor
CR to be constant with respect to a subject even in the case when
the zooming magnification is altered, is added thereto.
In this digital camera 1A, a selection screen related to the AF
cursor as shown in FIG. 28 is displayed by pressing the menu button
226; and when "constant with respect to the screen" is
selected by specifying a selection cursor SK, the position of the
AF cursor CR is maintained with respect to the screen, independent
of the zooming magnification in the same manner as the first preferred
embodiment. Moreover, when "constant with respect to the subject"
is selected, the position of the AF cursor CR is maintained with
respect to the subject. In this manner, by shifting the selection
cursor SK up and down, it is possible to switch functions of the
AF cursor CR.
The following description will discuss the operation for allowing
the AF cursor CR to be constant with respect to the subject independent
of the zooming magnification.
In the case when a zooming operation is carried out on a screen
G1 shown in FIG. 29 with a focal length of 35 mm to a screen with
a focal length of 70 mm, the screen is given as screen G2 shown
in FIG. 30. In this screen G2, the position of the AF cursor CR
is not the same as that of the AF cursor CR shown in screen G1 (FIG.
29), and follows the subject, and is maintained with respect to
the subject.
Here, an explanation will be briefly given of the principle for
allowing the position of AF cursor CR to be constant with respect
to the subject even in the case of varied zooming magnifications.
First, as illustrated in FIG. 31, supposing that the center of
the screen G is Oc, that x-axis is set in the horizontal direction
from the center Oc and that y-axis is set in the vertical direction
therefrom, the coordinates of the AF cursor CR in the case of a
focal length of 35 mm are set to (x.sub.35, y.sub.35), and the coordinates
of the AF cursor CR in the case of a focal length f are set to (x.sub.f,
y.sub.f). Then, the relationship between (x.sub.35, y.sub.35) and
(x.sub.f, y.sub.f) is represented by the following equations (5)
and (6): ##EQU2##
In other words, when coordinates (x.sub.35, y.sub.35) on the screen
of the AF cursor CR set with a focal length 35 mm are found, by
substituting the above-mentioned equations with the focal length
f after the zooming operation, the coordinates (x.sub.f, y.sub.f)
after the zooming operation can be obtained. The application of
the coordinates (x.sub.f, y.sub.f) after the zooming operation allows
the position of AF cursor CR to be constant with respect to the
subject even in the case of varied zooming magnifications.
Moreover, in the case when an electronic zooming operation of double
is carried out, if the enlarging rate with respect to the screen
with a focal length of 35 mm is found, the coordinates on the screen
after the zooming operation are found in the same manner. Therefore,
even in the case of the electronic zooming operation, the position
of the AF cursor CR is made constant with respect to the subject
as illustrated in FIG. 32.
In the case when the AF cursor CR is located at the end of the
screen, if a zooming operation is carried out, the AF cursor CR
is shifted following the subject so that, as illustrated in FIG.
33, the AF cursor CR tends to stick out from the screen. In this
case, as illustrated in FIG. 34, the AF cursor CR is allowed to
shift to the end of the screen G2. Thus, it is possible to prevent
the AF cursor CR from disappearing from the screen.
Here, in this case, as illustrated in FIG. 35, the AF cursor CR
may be further shifted toward the inner side of the screen as shown
in FIG. 34; that is, this may be shifted to a position close to
the end of the screen. In the example of FIG. 35, since the cursor
size is 16 pixels.times.16 pixels, it is shifted by a distance corresponding
to 8 pixels from the end; however, it can be shifted to a degree
in which the end of the cursor is made coincident with the edge
of the screen. Thus, it is possible to allow the shooter to have
an improved visibility in the AF cursor CR.
With the above-mentioned operations of the digital camera 1A, in
the same manner as the first preferred embodiment, it becomes possible
to improve the operability of the digital camera. Further, in the
digital camera 1A, since the position of the AF cursor is made constant
with respect to the subject, it is possible to carry out an appropriate
focusing operation with a desired focusing point, even when a zooming
operation is carried out.
<Modified Example>
In the above-mentioned preferred embodiments, a photometric area
related to AE is set in response to the AF cursor; however, in a
separate manner from the AF cursor, an AE cursor indicating the
center of the photometric area that corresponds to a photometric
point may be displayed.
Moreover, in the electronic zooming operation, not only trimming
but also a pixel interpolating operation may be carried out after
the trimming.
While the invention has been shown and described in detail, the
foregoing description is in all aspects illustrative and not restrictive.
It is therefore understood that numerous other modifications and
variations can be devised without departing from the scope of the
invention. |