Digital Camera Patent Abstract
A digital camera whose lens is detachable, comprising a judging
section for judging whether an image failure is caused due to dirt
adhering on an image sensor device unit including image sensor device,
an illuminating member which is disposed in the vicinity of the
image sensor device unit such that irradiation light can enter the
image sensor device and which is driven when at least the judgment
is made, a memory for storing a position of a picture element of
the image sensor device corresponding to image sensor data causing
image failure when the judging section judged that image failure
has been caused, and a correcting section for correcting the image
sensor data output from the image sensor device unit based on picture
element position data stored in the memory when a picture is photographed
after the lens is interchanged. Digital Camera Patent Claims
What is claimed is:
1. A digital camera whose lens is detachable, comprising: a judging
section for judging whether an image failure is caused due to dirt
adhering to an image sensor device unit including an image sensor
device; an illuminating member which is disposed in a vicinity of
the image sensor device unit such that irradiation light can enter
the image sensor device and which is driven at least when the judgment
is made; a memory for storing a position of a picture element of
the image sensor device corresponding to image sensor data causing
image failure when the judging section judges that image failure
has been caused; a correcting section for correcting the image sensor
data output from the image sensor device unit based on image position
data stored in the memory when a picture is photographed after the
lens is interchanged; and a liquid crystal display for displaying
the image data output from the image sensor device unit, wherein
the illuminating member also serves as a backlight which irradiates
illumination light from a back side of the liquid crystal display.
2. The digital camera according to claim 1, wherein the correcting
section corrects the image sensor data which correspond to picture
element position data stored in the memory and which were output
after the lens was interchanged, based on image sensor data corresponding
to a picture element position adjacent to the picture element position
data.
3. The digital camera according to claim 1, wherein the image sensor
device unit comprises at least one of a protecting glass for protecting
a surface of the image sensor device, and a filter.
4. The digital camera according to claim 1, wherein the memory
stores a picture element defect caused by the image sensor device,
and the correcting section corrects an image failure caused by dirt
when there is no picture element defect caused by the image sensor
device.
5. The digital camera according to claim 4, wherein the correcting
section corrects the image sensor data which correspond to picture
element position data stored in the memory and which were output
after the lens was interchanged, based on image sensor data corresponding
to a picture element position adjacent to the picture element position
data.
6. The digital camera according to claim 1, wherein the memory
stores a picture element defect caused by the image sensor device,
and the correcting section corrects an image failure caused by the
image sensor device.
7. The digital camera according to claim 1, further comprising
a second memory for storing a picture element defect caused by the
image sensor device, wherein the correcting section corrects an
image failure caused by dirt when there is no picture element defect
caused by the image sensor device.
8. The digital camera according to claim 1, wherein the correcting
section corrects the image sensor data which correspond to picture
element position data stored in the memory and which were output
after the lens was interchanged, based on image sensor data corresponding
to a picture element position which is adjacent to a picture element
position stored in the memory.
9. A digital camera whose lens is detachable, comprising: a judging
section for judging whether an image failure is caused due to dirt
adhering to an image sensor device unit including an image sensor
device; an illuminating member which is disposed in a vicinity of
the image sensor device unit such that irradiation light can enter
the image sensor device and which is driven at least when the judgment
is made; a memory for storing a position of a picture element of
the image sensor device corresponding to image sensor data causing
image failure when the judging section judges that image failure
has been caused; a correcting section for correcting the image sensor
data output from the image sensor device unit based on image position
data stored in the memory when a picture is photographed after the
lens is interchanged; and a warning section for warning a user that
a picture element which can not be corrected is present, when the
image sensor data can not be corrected by the correcting section.
10. The digital camera according to claim 9, wherein the warning
section warns the user when a number of picture elements which are
adjacent to the picture element position data stored in the memory
and which continuously cause image failure is greater than a predetermined
number.
11. The digital camera according to claim 9, wherein the warning
section warns the user when at least one of (i) the lens is interchanged
and (ii) a power supply is turned on.
12. A dirt position detecting method for a digital camera for judging
whether dirt is adhering to an image sensor device unit including
an image sensor element provided in a case of the digital camera,
whose lens is interchangeable, said method comprising: shielding
light entering the case; irradiating light onto the image sensor
device disposed in the case; judging whether image failure is caused
due to dirt by the irradiated light; and storing a position of a
picture element causing image failure when it is judged that the
image failure is caused.
13. The dirt position detecting method according to claim 12, wherein
light is irradiated onto the image sensor element by driving a backlight
which irradiates illumination light, from a back side, to a liquid
crystal display which displays image data output from the image
sensor device.
14. A digital camera whose lens is detachable, comprising: an image
sensor device unit including an image sensor device having a plurality
of picture elements; a memory for storing a position of a picture
element having an image failure in the image sensor device; an illuminating
member disposed in a vicinity of the image sensor device unit to
enable irradiation light to enter the image sensor device; a judging
section for judging whether the lens is interchanged; a driving
section for closing a shutter to prevent outside light from entering
the image sensor device unit, and for driving the illuminating member,
after the judging section judges that the lens is interchanged;
a detecting unit for detecting whether a picture element has an
image failure, when the illuminating member is driven; a determination
unit for removing a position of the picture element having the image
failure in the image sensor device, from a position of the picture
element having the image failure which is detected by the detecting
unit, to thereby determine a position of a picture element having
an image failure caused by dirt adhering to the image sensor device
unit; a storing unit for storing the position of the picture element
having an image failure caused by dirt adhering to the image sensor
device unit in the memory; and a correcting section for correcting
image sensor data output from the image sensor device unit based
on the position of the picture element which is stored in the memory,
when photographing is performed after the lens is interchanged.
15. The digital camera according to claim 14, further comprising
a liquid crystal display for displaying the image data output from
the image sensor device unit, and wherein the illuminating member
comprises a backlight which irradiates illumination light from a
back side of the liquid crystal display.
16. The digital camera according to claim 14, wherein the correcting
section corrects image sensor data which correspond to picture element
position data stored in the memory, and which were output after
the lens was interchanged, based on image sensor data corresponding
to a picture element position adjacent to a picture element position
indicated by the picture element position data.
17. The digital camera according to claim 14, further comprising
a warning section for warning a user that, a picture element which
can not be corrected is present, when the image sensor data can
not be corrected by the correcting section.
18. The digital camera according to claim 17, wherein the warning
section warns the user when a number of picture elements, which
are adjacent to the picture element position indicated by the picture
element position data stored in the memory, and which continuously
cause image failure, is greater than a predetermined number.
19. The digital camera according to claim 17, wherein the warning
section warns the user when at least one of (i) the lens is interchanged
and (ii) a power supply is turned on.
20. The digital camera according to claim 14, wherein the image
sensor device unit comprises at least one of a filter and a protecting
glass for protecting a surface of the image sensor device.
21. A digital camera according to claim 14, wherein the correcting
section corrects an image failure in the image sensor device.
22. A dirt position detecting method for a digital camera for judging
whether dirt adheres to an image sensor device unit including an
image sensor element provided in a case of the digital camera, whose
lens is interchangeable, said method comprising: judging whether
the lens is interchanged, closing a shutter to prevent outside light
from entering the image sensor device unit, after the lens is interchanged,
and then irradiating light onto the image sensor device disposed
in the case; judging whether an image failure is caused in the image
sensor device unit, while irradiating the light; specifying a position
of a picture element in which the image failure is caused by the
dirt adhering onto the image sensor device unit, based on defect
image position data stored in advance in the image sensor device;
storing in a memory image position data of the picture element in
which the image failure is caused by the dirt adhering onto the
image sensor device unit; and correcting the image sensor data output
from the image sensor device based on the image position data stored
in the memory, when photographing is performed after the lens is
interchanged.
Digital Camera Patent Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims the benefit of priority
from the prior Japanese Patent Applications No. 11-046437, filed
Feb. 24, 1999; and No. 2000-038526, filed Feb. 16, 2000, the entire
contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a digital camera to which a lens
can be attached and to a dirt position detecting method for the
digital camera.
A digital camera which photographs an image by a solid-state image
sensor device such as a CCD and stores the obtained image data in
a storage medium such as a memory or a hard disk becomes widespread.
A digital camera whose lens can be interchanged is also commercially
available like a camera which transfers image data onto a film.
However, in the case of the digital camera whose lens can be interchanged,
there is a problem that dirt or dust (which are collectively called
"dirt", hereinafter) is adhered to the image sensor device,
an image sensor device protecting glass fixed on the image sensor
device, a surface of a filter and the like, or an optical system
when the lens is interchanged. There is a problem that in the case
of an image which was shot in a state where dirt is adhered, since
light does not enter a picture element portion on which dirt is
adhered, image failure is caused.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provided a digital
camera which can correct the degradation of image quality of a shot
image even if dirt is adhered to an image sensor device, an image
sensor device protecting glass fixed on the image sensor device
or a filter when the lens is interchanged, and to provide a dirt
position detecting method for a digital camera for detecting a position
of dirt which causes image failure.
A digital camera of the present invention whose lens is detachable,
comprises: a judging section for judging whether an image failure
is caused due to dirt adhering on an image sensor device unit including
image sensor device; an illuminating member which is disposed in
the vicinity of the image sensor device unit such that irradiation
light can enter the image sensor device and which is driven when
at least the judgment is made; a memory for storing a position of
a picture element of the image sensor device corresponding to image
sensor data causing image failure when the judging section judged
that image failure has been caused; and a correcting section for
correcting the image sensor data output from the image sensor device
unit based on image position data stored in the memory when a picture
is photographed after the lens is interchanged.
Preferable modes of this semiconductor device are as follows: (a)
The digital camera further comprises a liquid crystal display for
displaying the image data output from the image sensor device unit,
wherein the illuminating member also serves as a backlight which
irradiates illumination light from a back side of the liquid crystal
display. (b) The correcting section corrects the image sensor data
which correspond to picture element position data stored in the
memory and which were output after the lens was interchanged, based
on image sensor data corresponding to picture element position adjacent
to the picture element position data. (c) The digital camera further
comprises a warning section for warning of a user of the fact that
there exists a picture element which can not be corrected when the
image sensor data could not be corrected by the correcting section.
The warning section warns when the number of picture elements which
are adjacent to the picture element position data stored in the
memory and which continuously cause image failure is greater than
the predetermined number. The warning section warns when the lens
is interchanged or a power supply is turned on. (d) The image sensor
device unit comprises at least one of a protecting glass for protecting
a surface of the image sensor device, and a filter. (e) A picture
element defect owned by the image sensor device itself is stored
in the memory, and the correcting section corrects an image failure
owned by the image sensor device itself. (f) The correcting section
corrects the image sensor data which correspond to picture element
position data stored in the memory and which were output after the
lens was interchanged, based on image sensor data corresponding
to picture element position adjacent to the picture element position
data. (g) The digital camera further comprises a second memory for
storing a picture element defect owned by the image sensor device
itself, wherein the correcting section corrects an image failure
caused by dirt when there is no defect picture element owned by
the image sensor device itself. (h) The correcting section corrects
the image sensor data which correspond to picture element position
data stored in the memory and which were output after the lens was
interchanged, based on image sensor data corresponding to picture
element position which is adjacent to a picture element position
stored in the memory.
A digital camera of the present invention whose lens is detachable,
comprises: a judging section for judging whether an image failure
is caused due to dirt adhering on an image sensor device unit; an
illuminating member which is disposed in the vicinity of the image
sensor device unit such that irradiation light can enter the image
sensor device and which is driven when at least the judgment is
made; a dirt position detecting section for storing a position of
a picture element of the image sensor device causing image failure
when the judging section judged that image failure has been caused;
a memory for storing a position of a picture element of the image
sensor device corresponding to a dirt position detected by the dirt
position detecting section; and a correcting section for correcting
the image sensor data output from the image sensor device unit based
on picture element position data stored in the memory when a picture
is photographed after the lens is interchanged.
A dirt position detecting method of the present invention for a
digital camera for judging whether dirt is adhering on an image
sensor device unit including an image sensor element provided in
a case of the digital camera whose lens is interchangeable, comprises
the steps of: shielding light entering the case; irradiating light
into the image sensor device disposed in the case; judging whether
image failure is caused because dirt adheres by the irradiated light;
and storing a position of a picture element causing image failure
when it is judged that the image failure is caused.
A preferred mode of the digital camera is as follows.
In the step for irradiating light to the image sensor element,
a backlight which irradiates illumination light, from a back side,
to a liquid crystal display which displays image data output from
the image sensor device, is driven, and the image sensor device
is allowed to irradiate light.
With the above configuration, the present invention has operations
and effects described below.
By irradiating LCD backlight to the CCD, by detecting picture element
of the CCD corresponding to image data causing image failure due
to dirt, and by removing picture element defect previously owned
by the CCD stored in the camera from the detected picture element,
it is possible to detect a position of the picture element having
the image failure. If the data corresponding to the picture element
position causing the image failure in a new image photographed after
the lens is interchanged are corrected from surrounding image data
in the picture element position, it is possible to suppress the
deterioration of image quality.
Additional objects and advantages of the invention will be set
forth in the description which follows, and in part will be obvious
from the description, or may be learned by practice of the invention.
The objects and advantages of the invention may be realized and
obtained by means of the instrumentalities and combinations particularly
pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
The accompanying drawings, which are incorporated in and constitute
a part of the specification, illustrate presently preferred embodiments
of the invention, and together with the general description given
above and the detailed description of the preferred embodiments
given below, serve to explain the principles of the invention.
FIG. 1 is a sectional view showing a general structure of a digital
camera according to one embodiment of the present invention;
FIG. 2 is a block diagram showing a circuit structure of the digital
camera according to the embodiment of the present invention;
FIG. 3 is a flowchart for explaining the operation from the time
when the power is turned on to the time when the power is turned
off of the digital camera according to the embodiment of the present
invention;
FIG. 4 is a flowchart for explaining the dirt position detecting
operation of the digital camera according to the embodiment of the
present invention; and
FIG. 5 is a flowchart for explaining the shooting operation of
the digital camera according to the embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be explained below
with reference to the drawings.
FIG. 1 is a sectional view showing a general structure of a digital
camera according to the embodiment of the present invention. FIG.
2 is a block diagram showing a circuit structure of the digital
camera according to the embodiment.
A lens 200 mounted to a mount 101 provided in a camera case 100
is detachable. The lens 200 is provided with a shutter or diaphragm
201. An image entering the camera case 100 through the lens 200
is formed on a surface of a CCD 103' in a CCD unit 103 disposed
on a PC board 102. In addition to the CCD 103', a filter and a CCD
protecting glass (not shown) are fixed to the CCD unit 103.
Image data formed on the CCD 103' are subjected to image processing
and then displayed on an LCD 105. When a backlight 104 is lit, if
a user peeps into a finder 108, he or she can see the image displayed
on the LCD 105 through lenses 107 and a mirror 106.
Connected to a CPU 110 in the camera case 100 are the CCD 103',
the backlight 104, the LCD 105, a communication 111, an A/D converter
113, an image buffer memory 114, an image processor 115 comprising
a DSP, a picture element defect position storing memory 116 for
storing a fact that there exists a defect in a predetermined picture
element itself in the CCD, a dirt position storing memory 117 for
storing a position of a picture element in the CCD 103' having an
image failure due to dirt, and a release SW 120. It is preferable
to use nonvolatile memories as the picture element defect position
storing memory 116 and the dirt position storing memory 117. It
is needless to say that the picture element defect position storing
memory 116 and the dirt position storing memory 117 may use the
same memory chip and only their addresses may be changed from each
other.
Information concerning kind of the lens 200, an instruction signal
from the CPU 110 and the like are transmitted by the communications
111 and 202 respectively provided in the camera case 100 and the
lens 200.
Next, the operation from the time when the power is turned on to
the time when the power is turned off will be explained with reference
to FIG. 3. In the following explanation of the operation, the CPU
110 controls various parts in accordance with a program. First,
if a power supply switch is turned on, a picture element defect
of the CCD 103' and a picture element of the CCD 103' corresponding
to image data having image failure caused by dirt are detected,
and an address of the picture element detected by removing a picture
element defect existing from the beginning is stored in the dirt
position storing memory 117 (step S1). A method for detecting a
picture element having a problem in its image data caused by dirt
will be explained later.
Next, it is judged whether the lens was interchanged by detecting
that the lens 200 was attached or detached (step S2). When the lens
200 was attached or detached, a picture element corresponding to
image data having an image failure caused by dirt is again detected
as in step S1, and the address of the detected picture element of
the CCD 103' is stored in the dirt position storing memory 117 (step
S3). Then, it is judged whether the power supply switch is turned
off (step S4). If the power supply switch was turned off, the procedure
is completed here. If the power supply switch was not turned off,
the flow proceeds back to step S2.
When it is judged that the lens was not interchanged in step S2,
a state of the release SW 120 is detected to judge whether the release
SW 120 was turned on (step S5). When the release SW 120 was not
turned ON, it is judged the power supply switch was turned off (step
S4).
When the release SW 120 was turned on, an image entering the CCD
103' is photographed (step S6). Then, the addresses of the picture
element defect and image failure picture element stored in the picture
element defect position storing memory 116 and the dirt position
storing memory 117 are read out, and it is judged whether a picture
element adjacent to the picture element stored in the picture element
defect position storing memory 116 and the dirt position storing
memory 117 has failure (step S7). When the adjacent picture element
has no failure, it is judged whether the power supply switch was
turned off (step S4).
When the adjacent picture element has a failure, it is judged whether
the number of picture elements continuously causing failure is greater
than the given number (step S8). If the number is not greater than
the given number, it is judged whether the power supply switch was
turned off (step S4). If the number is greater than the given number,
the user is warned and advised to remove the dirt adhering to the
CCD 103' (step S9). As the warning, the user is warned by beep tones
using a PCV and the like, or by warning display for displaying the
position of the dirt on the LCD 105 using highlight.
Next, a method for detecting a position of a picture element having
failure caused by dirt will be explained. FIG. 4 is a flowchart
showing the dirt position detecting method according to the embodiment
of the present invention.
First, the shutter or the diaphragm 201 is completely closed so
that no light except from the backlight 104 does not enter the CCD
103' (step S21). Instead of closing the shutter or the diaphragm
201, a lens cap may be put on. Next, the backlight 104 is allowed
to light (step S22). The order of the steps S21 and S22 may be reversed.
Next, the image data are read out by the CCD 103', the detected
image data are converted into digital data by the A/D converter
113, and the converted digital data are stored in the image buffer
memory 114 (step S23).
Next, the backlight 104 is allowed to light out (step S24). The
shutter or the diaphragm 201 is opened, thereby bringing back the
camera into its normal state (step S25). The order of the steps
S24 and S25 may be reversed.
Then, image data respectively corresponding to positions of picture
elements stored in the image buffer memory 114 are called up in
sequence (step S26). The called-up image data value is compared
with a preset threshold level (step S27). If dirt is adhered to
the CCD, the amount of light entering a picture element in the corresponding
position is reduced. Therefore, if the obtained data are compared
with the set threshold level, it is possible to detect a picture
element having image failure. If outside light enters the camera
body when the failure is detected, the obtained data may become
higher than the threshold level in some cases even though the failure
has been caused. Therefore, the outside light must be shut off.
When the image data value is lower than the threshold level, the
value is compared with a position of picture element defect which
is previously factory-stored in a picture element defect position
storing memory, thereby judging whether there is a picture element
defect (step S28). Only when it is judged that the defect is not
caused by the picture element defect, the position of the corresponding
picture element is stored in the dirt position storing memory (step
S29). Thereafter, it is confirmed whether all the picture elements
are read out (step S30).
In step S30, if it is judged that the reading-out operation of
all the picture elements is not completed, the flow proceeds back
to step S26, where image data in the next picture element are read
out.
Then, if the detection of all the picture elements is completed
and a picture element photographing the image failure due to dirt
is detected in step S30, it is checked whether there exists image
failure in a picture element adjacent to the detected picture element
position due to picture element defect or dirt (step S31). If the
adjacent picture element has defect or failure, it is judged whether
the number of picture elements continuously causing image failure
is greater than the constant number (step S32). If the number is
not greater than the constant number, it is judged whether the power
supply switch was turned off (step S4). If the number of the continuous
picture elements is greater than the constant number, the user is
warned and advised to remove the dirt adhering to the CCD 103' (step
S33). As the warning, the user is warned by beep tones using a PCV
and the like, or by warning display for displaying the position
of the dirt on the LCD 105 using highlight. By warning the user
here, if the picture element defect could not be corrected, it is
possible to advise the user to remove the dirt when the power is
on or the lens is interchanged. Further, the user may be warned
absolutely when the power is on or the lens is interchanged. If
it is judged that the adjacent picture element has no defect or
there is no dirt, the flow is completed.
Next, the operation at the time of photographing (step S6) will
be explained using a flowchart shown in FIG. 5. First, the image
data obtained by the CCD 103' are converted into digital data by
the A/D converter 113, and the converted data are stored in the
image buffer memory 114 (step S41).
Then, the image data of the picture elements are read out in sequence
from the image buffer memory 114 (step S42). Address of the read-out
image data and address of picture element registered in the picture
element defect position storing memory 116 are compared with each
other, and it is checked whether the read-out image data have defect
(step S43).
If the read-out image data did not have defect, address of the
read-out image data and address of position of picture element registered
in the dirt position storing memory 117 are compared with each other,
and it is checked whether the read-out image data have defect caused
by dirt (step S44).
In steps S43 and S44, if the address of the read-out image data
corresponds to address of the picture element defect or address
of picture element having dirt, the image data are corrected using
surrounding normal image data (step S45). If there is no defect
in eight picture elements adjacent to the read-out image data, the
image data can be corrected excellently.
Thereafter, it is checked whether all the picture elements have
been read out (step S46), and if all the picture elements have not
yet been read out, the flow again proceeds back to step S42, where
the next picture element is read out. When it is judged that all
the picture elements have been read out, this means that all the
image data corresponding to one sheet have been corrected and thus,
the image data are subjected to image processing such as compression
(step S47), and the photographing is completed.
According to the digital camera of the present embodiment, picture
elements causing image failure is detected by irradiating the CCD
with light from the LCD backlight, and the picture element having
the defect is removed from the detected picture elements so that
the picture element causing the image failure due to dirt can be
detected. Further, by correcting image data causing image failure
from image data located in the vicinity, it is possible suppress
deterioration of the image quality without using special illuminating
members or the like.
Furthermore, when the failure could not be corrected, it is possible
to advise the user to remove the dirt by warning the user of the
fact that the failure could not be corrected.
The present invention should not be limited to the above embodiment,
and it is possible to variously deform and carry out the present
invention without departing the subject of the present invention.
Additional advantages and modifications will readily occur to those
skilled in the art. Therefore, the invention in its broader aspects
is not limited to the specific details and representative embodiments
shown and described herein. Accordingly, various modifications may
be made without departing from the spirit or scope of the general
inventive concept as defined by the appended claims and their equivalents. |