U.S. patent application number 16/354193 was filed with the patent office on 2019-07-11 for image capturing device.
The applicant listed for this patent is ACER INCORPORATED. Invention is credited to Jia-Ling Jhang, Wei-Kuo Shih.
Application Number | 20190215453 16/354193 |
Document ID | / |
Family ID | 59686722 |
Filed Date | 2019-07-11 |
United States Patent
Application |
20190215453 |
Kind Code |
A1 |
Jhang; Jia-Ling ; et
al. |
July 11, 2019 |
IMAGE CAPTURING DEVICE
Abstract
An image capturing device is provided. The image capturing
device includes an image sensing circuit, a determination circuit
and an output circuit. The image sensing circuit is utilized for
capturing a first test image at a first time point and capturing a
second test image at a second time point. The determination circuit
is utilized for calculating a first image feature value associated
with a color value of the first test image and a second image
feature value associated with a color value of the second test
image, calculating a difference value between the first image
feature value and the second image feature value and comparing the
difference value with a threshold value to generate a determination
result. The output circuit is utilized for outputting the images
generated by the image capturing device according to the
determination result.
Inventors: |
Jhang; Jia-Ling; (New Taipei
City, TW) ; Shih; Wei-Kuo; (New Taipei City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ACER INCORPORATED |
New Taipei City |
|
TW |
|
|
Family ID: |
59686722 |
Appl. No.: |
16/354193 |
Filed: |
March 15, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15603430 |
May 23, 2017 |
10306138 |
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16354193 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 21/83 20130101;
G06T 7/97 20170101; G06F 2221/031 20130101; H04N 9/735 20130101;
H04N 5/23229 20130101; H04N 5/232 20130101; G06F 21/629 20130101;
H04N 5/2351 20130101; G06T 2207/20224 20130101 |
International
Class: |
H04N 5/232 20060101
H04N005/232; G06F 21/83 20060101 G06F021/83; H04N 9/73 20060101
H04N009/73; G06F 21/62 20060101 G06F021/62; H04N 5/235 20060101
H04N005/235; G06T 7/00 20060101 G06T007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2017 |
TW |
106106926 |
Claims
1. An image capturing device, comprising: an image sensing circuit,
for capturing a first test image at a first time point and
capturing a second test image at a second time point; a
determination circuit, for calculating a first image feature value
of the first test image and a second image feature value of the
second test image, calculating a difference value between the first
image feature value and the second image feature value, and
comparing the difference value with a threshold value to generate a
determination result, wherein the first image feature value of the
first test image is associated with a color value of the first test
image and the second image feature value of the second test image
is associated with a color value of the second test image; and an
output circuit, for outputting the images generated by the image
capturing device according to the determination result; wherein the
determination result indicates outputting the images generated by
the image capturing device when the difference value is greater
than the threshold value, and the output circuit accordingly
outputs the images generated by the image capturing device.
2. The image capturing device of claim 1, wherein the difference
value is an absolute difference between the first image feature
value and the second image feature value.
3. An image capturing device, comprising: an image sensing circuit,
for capturing a first test image at a first time point and
capturing a second test image at a second time point; a
determination circuit, for calculating a first image feature value
of the first test image and a second image feature value of the
second test image, calculating a difference value between the first
image feature value and the second image feature value, and
comparing the difference value with a threshold value to generate a
determination result, wherein the first image feature value of the
first test image is associated with a brightness value of the first
test image and the second image feature value of the second test
image is associated with a brightness value of the second test
image; and an output circuit, for outputting the images generated
by the image capturing device according to the determination
result; wherein the determination result indicates outputting the
images generated by the image capturing device when the difference
value is greater than the threshold value, and the output circuit
accordingly outputs the images generated by the image capturing
device.
4. An image capturing device, comprising: an image sensing circuit,
for capturing a first test image at a first time point and
capturing a second test image at a second time point; a
determination circuit, for calculating a first image feature value
of the first test image and a second image feature value of the
second test image, calculating a difference value between the first
image feature value and the second image feature value, and
comparing the difference value with a threshold value to generate a
determination result, wherein the first image feature value of the
first test image is associated with a focal distance of the first
test image and the second image feature value of the second test
image is associated with a focal distance of the second test image;
and an output circuit, for outputting the images generated by the
image capturing device according to the determination result;
wherein the determination result indicates outputting the images
generated by the image capturing device when the difference value
is greater than the threshold value, and the output circuit
accordingly outputs the images generated by the image capturing
device.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 15/603,430, filed on May 23, 2017 and entitled
"IMAGE OUTPUT METHOD AND IMAGE CAPTURING DEVICE", which is included
in its entirety herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to an image capturing device,
and more particularly, to an image capturing device capable of
improving the security of image data.
2. Description of the Prior Art
[0003] With the development of technology and progress of industry,
digital cameras have been widely utilized in all kinds of
electronic devices, such as laptops, tablets, desktops, mobile
phones, wearable devices, smart TVs and so on. Since the electronic
devices have ability to connect to the Internet, users utilize the
digital cameras mounted on the electronic devices to take photos
and share the photos to other electronic devices via the Internet.
However, the electronic devices with the ability to connect to the
Internet are easy to be invaded by hackers via remote control, so
as to manipulate the cameras, peep or steal the images taken by the
camera, thus threatening the privacy and security of the users.
Therefore, there is a need for improvement.
SUMMARY OF THE INVENTION
[0004] Therefore, the present invention primarily provides an image
output method and an image capturing device, which is capable of
improving the security of image data to solve the above mentioned
problems.
[0005] The present invention discloses an image capturing device,
comprising: an image sensing circuit, for capturing a first test
image at a first time point and capturing a second test image at a
second time point; a determination circuit, for calculating a first
image feature value of the first test image and a second image
feature value of the second test image, calculating a difference
value between the first image feature value and the second image
feature value, and comparing the difference value with a threshold
value to generate a determination result, wherein the first image
feature value of the first test image is associated with a color
value of the first test image and the second image feature value of
the second test image is associated with a color value of the
second test image; and an output circuit, for outputting the images
generated by the image capturing device according to the
determination result; wherein the determination result indicates
outputting the images generated by the image capturing device when
the difference value is greater than the threshold value, and the
output circuit accordingly outputs the images generated by the
image capturing device.
[0006] The present invention further discloses an image capturing
device, comprising: an image sensing circuit, for capturing a first
test image at a first time point and capturing a second test image
at a second time point; a determination circuit, for calculating a
first image feature value of the first test image and a second
image feature value of the second test image, calculating a
difference value between the first image feature value and the
second image feature value, and comparing the difference value with
a threshold value to generate a determination result, wherein the
first image feature value of the first test image is associated
with a brightness value of the first test image and the second
image feature value of the second test image is associated with a
brightness value of the second test image; and an output circuit,
for outputting the images generated by the image capturing device
according to the determination result; wherein the determination
result indicates outputting the images generated by the image
capturing device when the difference value is greater than the
threshold value, and the output circuit accordingly outputs the
images generated by the image capturing device.
[0007] The present invention further discloses an image capturing
device, comprising: an image sensing circuit, for capturing a first
test image at a first time point and capturing a second test image
at a second time point; a determination circuit, for calculating a
first image feature value of the first test image and a second
image feature value of the second test image, calculating a
difference value between the first image feature value and the
second image feature value, and comparing the difference value with
a threshold value to generate a determination result, wherein the
first image feature value of the first test image is associated
with a focal distance of the first test image and the second image
feature value of the second test image is associated with a focal
distance of the second test image; and an output circuit, for
outputting the images generated by the image capturing device
according to the determination result; wherein the determination
result indicates outputting the images generated by the image
capturing device when the difference value is greater than the
threshold value, and the output circuit accordingly outputs the
images generated by the image capturing device.
[0008] These and other objectives of the present invention will no
doubt become obvious to those of ordinary skill in the art after
reading the following detailed description of the preferred
embodiment that is illustrated in the various figures and
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic diagram illustrating an image
capturing device according to an embodiment of the present
invention.
[0010] FIG. 2 is a schematic diagram illustrating a procedure
according to an embodiment of the present invention.
[0011] FIGS. 3-5 are schematic diagrams illustrating different
procedures according to alternative embodiments of the present
invention.
DETAILED DESCRIPTION
[0012] Please refer to FIG. 1, which is a schematic diagram
illustrating an image capturing device 10 according to an
embodiment of the present invention. The image capturing device 10
can be utilized in all kinds of electronic devices, such as
notebooks, tablets, desktops, mobile phones, wearable devices,
smart TVs, but not limited thereto. The image capturing device 10
includes an image sensing unit 102, a determination unit 104 and an
output unit 106.
[0013] The image sensing unit 102 is utilized for capturing images.
The image sensing unit 102 can be a charge-coupled device (CCD)
sensor, a complementary metal oxide semiconductor (CMOS) sensor, or
other image sensors. The image captured by the image sensing unit
102 can be raw images. The image captured by the image sensing unit
102 can be outputted directly to other external devices. The image
captured by the image sensing unit 102 can also be provided to an
image signal processor (ISP) of the image capturing device 10, such
that the image signal processor handles corresponding image
processing procedure of the captured image and outputs for
consequent application. For example, image processing procedure
executed by the image signal processor can be image format
transformation, auto white balance (AWB), auto exposure (AE), auto
focus (AF), contrast adjustment, saturation adjustment, noise
elimination, interpolation, edge enhancement and the like, but not
limited thereto. The image sensing unit 102 can capture images
consecutively. For example, the image sensing unit 102 captures
test images in a test mode and captures relative images in a normal
mode. In the test mode, the image sensing unit 102 captures a first
test image at a first time point and a second test image at a
second time point.
[0014] The determination unit 104 is used for calculating a first
image feature value of a first test image and a second image
feature value of a second test image. And the determination unit
104 determines whether to output images generated by the image
capturing device 10 according to the first image feature value of
the first test image and the second image feature value of the
second test image, and accordingly generates a determination
result. The output unit 106 outputs the images generated by the
image capturing device 10 according to the determination result
generated by the determination unit 104. In an embodiment, at least
one of the determination unit 104 and the output unit 106 can be
implemented by an image signal processor.
[0015] In brief, the image capturing device 10 of the present
invention can determine whether to output the images generated by
the image capturing device 10 according to image feature values of
the captured images at different time points. That is, after
determination and authentication of the determination unit 104 and
the output unit 106, the images generated by the image capturing
device 10 can be outputted, so as to provide a security control
procedure of image data access. As such, the invention can
effectively prevent hackers from stealing or peeping the images
generated by the image capturing device 10 via remote control, and
therefore, improving security of image data.
[0016] For an illustration of the operations of the image capturing
device 10, please refer to FIG. 2, which is a schematic diagram
illustrating a procedure 20 according to an embodiment of the
present invention. The procedure 20 includes the following
steps:
[0017] Step S200: Start.
[0018] Step S202: Capture the first test image at the first time
point and capture the second test image at the second time
point.
[0019] Step S204: Calculate the first image feature value of the
first test image and the second image feature value of the second
test image.
[0020] Step S206: Determine whether to output the image generated
by the image capturing device according to the first image feature
value of the first test image and the second image feature value of
the second test image.
[0021] Step S208: End.
[0022] According to the procedure 20, the present invention can
control whether to output the images based on the images captured
by the image sensing unit 102 for improving the security of the
image data. When the image capturing device 10 receives image
access requests or before the image capturing device 10 is ready to
output the images, first, in Step S202, the image capturing device
10 enters a test mode, and the image sensing unit 102 captures a
first test image at a first time point and captures a second test
image at a second time point. For example, the second time point is
after the first time point. A time interval between the first time
point and the second time point can be determined according to
system requirements. For example, the time interval between the
first time point and the second time point is 30 microseconds (ms).
For another example, the time interval between the first time point
and the second time point is 5 seconds(s).
[0023] In Step S204, the determination unit 104 calculates a first
image feature value of the first test image and a second image
feature value of the second test image. For example, the first
image feature value of the first test image can be a brightness
value, a color value, a focal distance (focal length) or any other
image feature values associated with the first test image. The
second image feature value of the second test image can be a
brightness value, a color value, a focal distance or any other
image feature values associated with the second test image.
[0024] In Step S206, the determination unit 104 determines whether
to output the images generated by the image capturing device 10
according to the first image feature value of the first test image
and the second image feature value of the second test image, and
accordingly generates a determination result. The determination
unit 104 can calculate an image difference value between the first
image feature value and the second image feature value. For
instance, the determination unit 104 can subtract the second image
feature value from the first image feature value to calculate a
difference value between the first image feature value and the
second image feature value. As such, the calculated difference
value is the image difference value between the first image feature
value and the second image feature value. For another example, the
determination unit 104 can calculate an absolute difference between
the first image feature value and the second image feature value,
and the absolute difference is the image difference value between
the first image feature value and the second image feature value.
As such, the image difference value represents a variation between
the first test image at the first time point and the second test
image at the second time point. Then, the determination unit 104
compares the image difference value with a threshold and generates
the determination result accordingly. For example, when the image
difference value is greater than the threshold, the determination
result indicates to output the images generated by the image
capturing device 10. When the image difference value is equal to or
smaller than the threshold, the determination result indicates not
to output the images generated by the image capturing device
10.
[0025] Furthermore, the output unit 106 outputs the images
generated by the image capturing device 10 according to the
determination result determined by the determination unit 104. In
an embodiment, when the determination result indicates to output
the images generated by the image capturing device 10, the output
unit 106 outputs the images generated by the image capturing device
10 to other external devices or other devices, wherein the images
generated by the image capturing device 10 includes at least one of
test images captured by the image sensing unit 102 in the test
mode, images captured by the image sensing unit 102 in the normal
mode, images processed by the image processor. In other words, the
output unit 106 can output the test images captured by the image
sensing unit 102 of the image capturing device 10 in the test mode
and/or output the images captured by the image sensing unit 102 of
the image capturing device 10 in the normal mode. Or, the output
unit 106 can output the images processed by the image processor of
the image capturing device 10. Therefore, after the determination
and authentication procedure of the procedure 20, if the
determination result indicates to output the images generated by
the image capturing device 10, the image capturing device 10
performs image output procedure normally.
[0026] In an embodiment, when the determination result indicates
not to output the images generated by the image capturing device
10, the output unit 106 will not perform any operation. In such a
situation, the images generated by the image capturing device 10
will not be outputted and provided to other devices. For example,
when the determination result indicates not to output the images
generated by the image capturing device 10, the output unit 106 can
output (or control a display device to display) a monochrome image,
for instance, a black image or a white image, to indicate not
allowable to access the images generated by the image capturing
device 10. That is, in this situation, if the determination result
indicates not to output the images generated by the image capturing
device 10, the image capturing device 10 will not be allowed to
perform the image output procedure normally.
[0027] On the other hand, after the determination unit 104
generates the corresponding determination result, the image
capturing device 10 can inform a user whether the images generated
by the image capturing device 10 can be outputted (or not) by an
alarming unit (not illustrated in the figure). For example, the
alarming unit can generate alarm signals (via all kinds of ways,
e.g., words, voices, lights or vibration) to inform the user.
[0028] Please refer to FIG. 3, which is a schematic diagram
illustrating a procedure 30 according to an embodiment of the
present invention. The procedure 30 includes the following
steps:
[0029] Step S300: Start.
[0030] Step S302: Capture the first test image and the second test
image.
[0031] Step S304: Calculate the brightness value associated with
the first test image and the brightness value associated with the
second test image.
[0032] Step S306: Calculate the image difference value between the
brightness value associated with the first test image and the
brightness value associated with the second test image.
[0033] Step S308: Determine whether the image difference value is
greater than the threshold; if yes, perform the Step S310; if no,
perform the Step S312.
[0034] Step S310: Output the image.
[0035] Step S312: Not output the image.
[0036] According to the procedure 30, in Step S302, when the image
capturing device 10 receives image access requests or before the
image capturing device 10 is ready to output the images, the image
capturing device 10 enters a test mode, and the image sensing unit
102 captures a first test image at a first time point and captures
a second test image at a second time point.
[0037] In Step S304, the determination unit 104 calculates the
brightness value associated with the first test image and the
brightness value associated with the second test image. The pixel
brightness value of the first test image can be an average
brightness value of pixels of at least a portion of the first test
image. The brightness value of the second test image can be an
average brightness value of pixels of at least a portion of the
second test image. In detail, the determination unit 104
respectively detects the pixel brightness value of each pixel of at
least a portion of the first test image, and calculates an average
of brightness values of all pixels of the at least a portion of the
first test image, and the calculated result is the brightness value
associated with the first test image. Similarly, for the second
test image, the determination unit 104 respectively detects the
pixel brightness value of each pixel of at least a portion of the
second test image and calculates an average of brightness values of
all pixels of at least a portion of the second test image, and the
calculated result is the brightness value associated with the
second test image.
[0038] For example, assume that a first region of the images
captured by the image sensing unit 102 usually corresponds to a
head region of the user when using the image capturing device 10.
The determination unit 104 can respectively detect the pixel
brightness value of each pixel of the first region of the first
test image and the second test image. And then, the determination
unit 104 calculates the average pixel brightness value of all
pixels of the first region of the first test image to obtain the
brightness value associated with the first test image, and
calculates the average pixel brightness value of all pixels of the
second region of the second test image to obtain the brightness
value associated with the second test image.
[0039] For example, calculation of the whole region of the image is
also available. The determination unit 104 can respectively detect
the brightness value of each pixel of the first test image and the
second test image. After that, the determination unit 104
calculates an average of brightness values of all pixels of the
first test image to obtain the brightness value associated with the
first test image, i.e. taking the calculated average value as the
brightness value associated with the first test image. The
determination unit 104 calculates an average of brightness values
of all pixels of the second test image to obtain the brightness
value associated with the second test image, i.e. taking the
calculated average value as the brightness value associated with
the second test image.
[0040] In Step S306, the determination unit 104 calculates an image
difference value between the brightness value associated with the
first test image and the brightness value associated with the
second test image. For example, the determination unit 104 can
subtract the brightness value associated with the second test image
from the brightness value associated with the first test image, so
as to calculate a difference between the brightness value
associated with the first test image and the brightness value
associated with the second test image. In this situation, the
calculated result is the image difference value between the
brightness value associated with the first test image and the
brightness value associated with the second test image. The
calculated image difference value can show a variation between the
first test image and the second test image. For example, the
determination unit 104 can calculate an absolute difference between
the brightness value associated with the first test image and the
brightness value associated with the second test image, and the
calculated result is the image difference value between the
brightness value associated with the first test image and the
brightness value associated with the second test image.
[0041] Since an object remains stationary in the images,
neighboring frames usually do not exhibit any significant
variation, so that the image difference value is usually small.
When the object is moving in the images, the image difference value
will be larger. Moreover, the user's body usually moves slightly or
slenderly and is not completely stationary when the user is in
shooting range of the image capturing device 10. Therefore, in Step
S308, the determination unit 104 can compare the image difference
value calculated in Step S306 with a threshold to generate a
determination result. For example, when the image difference value
is greater than the threshold, this means that the user is in the
shooting range of the image capturing device 10 and the user is
using the image capturing device 10. As a result, the determination
result indicates to output the images generated by the image
capturing device 10. The output unit 106 accordingly outputs the
images generated by the image capturing device 10 (Step S310). On
the other hand, when the image difference value is smaller than or
equal to the threshold, this means that the user is not in the
shooting range of the image capturing device 10. As such, the
determination result indicates not to output the images generated
by the image capturing device 10. The output unit 106 will not
output any image generated by the image capturing device 10, or the
output unit 106 controls a display device to display a black image
(Step S312). In other words, the present invention can determine
whether to output the images generated by the image capturing
device 10 according to the variation of brightness of the images,
and effectively improve the security of image data access.
[0042] Besides, in an embodiment, the relative operations performed
by the determination unit 104 in steps S304, S306 and S308, can
also be implemented by an auto exposure module of an image signal
processor.
[0043] Please refer to FIG. 4, which is a schematic diagram of a
procedure 40 according to another embodiment of the present
invention. The procedure 40 includes the following steps:
[0044] Step S400: Start.
[0045] Step S402: Capture the first test image and the second test
image.
[0046] Step S404: Calculate the color value associated with the
first test image and the color value associated with the second
test image.
[0047] Step S406: Calculate the image difference value between the
color value associated with the first test image and the color
value associated with the second test image.
[0048] Step S408: Determine whether the image difference value is
greater than the threshold; if yes, perform Step S410; if no,
perform Step S412.
[0049] Step S410: Output the image.
[0050] Step S412: Not output the image.
[0051] According to the procedure 40, in Step S402, when the image
capturing device 10 receives image access requests or before the
image capturing device 10 is ready to output the images. The image
capturing device 10 enters a test mode, and the image sensing unit
102 captures a first test image at a first time point and captures
a second test image at a second time point.
[0052] In Step S404, the determination unit 104 calculates the
color value associated with the first test image and the color
value associated with the second test image. The color value of the
first test image can be an average of color values of pixels of at
least a portion of the first test image. The color value of the
second test image can be an average of color values of pixels of at
least a portion of the second test image. The color value can be at
least a color component value of three-primary colors or component
value of other colors. In detail, the determination unit 104
respectively detects the color value of each pixel of at least a
portion of the first test image, and calculates the average of
color values of all pixels of the at least a portion of the first
test image, so that the calculated result is the color value
associated with the first test image. Similarly, for the second
test image, the determination unit 104 respectively detects the
pixel color value of each pixel of at least a portion of the second
test image, and calculates the average of color values of all
pixels of the at least a portion of the second test image, so that
the calculated result is the color value associated with the second
test image.
[0053] For example, calculation of blue component value of the
whole region of the image is also available. The determination unit
104 can respectively detect blue component value of each pixel of
the first test image and the second test image. After that, the
determination unit 104 calculates the average of blue component
values of all pixels of the first test image to obtain the color
value associated with the first test image, i.e. taking the
calculated average value as the color value associated with the
first test image. The determination unit 104 calculates the average
of blue component values of all pixels of the second test image to
obtain the color value associated with the second test image, i.e.
taking the calculated average value as the color value associated
with the second test image.
[0054] In Step S406, the determination unit 104 calculates an image
difference value between the color value associated with the first
test image and the color value associated with the second test
image. For example, the determination unit 104 can calculate a
difference or an absolute difference between the color value
associated with the first test image and the color value associated
with the second test image. In this situation, the calculated
result is the image difference value between the color value
associated with the first test image and the color value associated
with the second test image. The calculated image difference value
can show a color variation between the first test image and the
second test image.
[0055] Therefore, in Step S408, the determination unit 104 can
compare the image difference value calculated in Step S406 with a
threshold to generate a determination result. For example, assume
that the blue component value is taken as a calculation basis in
Step S404. When the image difference value is greater than the
threshold, this means that a blue or similar color object is
approaching the shooting range of the image capturing device 10. As
such, the determination result indicates to output the images
generated by the image capturing device 10. The output unit 106
accordingly outputs the images generated by the image capturing
device 10 (Step S410). On the other hand, when the image difference
value is smaller than or equal to the threshold, this means that no
blue or similar color object is approaching the shooting range of
the image capturing device 10. As such, the determination result
indicates not to output the images generated by the image capturing
device 10. The output unit 106 will not output any image generated
by the image capturing device 10, or the output unit 106 controls a
display device to display a black image (Step S412). That is, the
present invention can take colors as a key of image output control.
For example, when the blue component value is used as the
calculation basis and the user takes a blue card in front of lens
of the image sensing unit 102, the output unit 106 will output the
images captured by the image capturing device 10 after performing
the steps of the procedure 40. In other words, the present
invention can determine whether to output the images generated by
the image capturing device 10 according to the variation of the
color value of the images, and effectively improve the security of
image data access.
[0056] In an embodiment, relative operations performed by the
determination unit 104 in steps S406, S406 and Step S408 can also
be implemented by an auto white balance module of an image signal
processor.
[0057] Please refer to FIG. 5, which is a schematic diagram of a
procedure 50 according to another embodiment of the present
invention. The procedure 50 includes the following steps:
[0058] Step S500: Start.
[0059] Step S502: Capture the first test image and the second test
image.
[0060] Step S504: Calculate the focal distance associated with the
first test image and the focal distance associated with the second
test image.
[0061] Step S506: Calculate the image difference value between the
focal distance associated with the first test image and the focal
distance associated with the second test image.
[0062] Step S508: Determine whether the image difference value is
greater than the threshold; if yes, perform Step S510; if no,
perform Step S512.
[0063] Step S510: Output the image.
[0064] Step S512: Not output the image.
[0065] According to the procedure 50, in Step S502, when the image
capturing device 10 receives image access requests or before the
image capturing device 10 is ready to output the images. The image
capturing device 10 enters a test mode, and the image sensing unit
102 captures a first test image at a first time point and captures
a second test image at a second time point.
[0066] In Step S504, the determination unit 104 calculates the
focal distance associated with the first test image and the focal
distance associated with the second test image. The focal distance
of the first test image can be the focal distance of at least a
portion of the first test image. The focal distance of the second
test image can be the focal distance of at least a portion of the
second test image. For example, assume that a first region of the
images captured by the image sensing unit 102 is taken as a focal
distance evaluation region. The determination unit 104 respectively
calculates a first focal distance corresponding to the first region
of the first test image and a second focal distance corresponding
to the first region of the second test image. For example, assume
that the whole region of the images captured by the image sensing
unit 102 can be taken as the focal distance evaluation region. The
determination unit 104 can respectively calculate the first focal
distance corresponding to the first test image and the second focal
distance corresponding to the second test image.
[0067] In Step S506, the determination unit 104 calculates an image
difference value between the first focal distance associated with
the first test image and the second focal distance associated with
the second test image. For example, the determination unit 104 can
calculate a difference between the first focal distance associated
with the first test image and the second focal distance associated
with the second test image. In this situation, the calculated
result is the image difference value between the first focal
distance associated with the first test image and the second focal
distance associated with the second test image. The calculated
image difference value can show a variation of an object's movement
in the first test image and the second test image. For example, the
determination unit 104 can calculate the absolute difference
between the first focal distance associated with the first test
image and the second focal distance associated with the second test
image, and the calculated result is the image difference value
between the focal distance associated with the first test image and
the focal distance associated with the second test image.
[0068] In Step S508, the determination unit 104 can compare the
image difference value calculated in Step S506 with a threshold to
generate a determination result. For example, when the image
difference value is greater than the threshold, this means that a
user is moving, so that the determination result indicates to
output the images generated by the image capturing device 10. The
output unit 106 accordingly outputs the images generated by the
image capturing device 10 (Step S510). On the other hand, when the
image difference value is smaller than or equal to the threshold,
this means that no user exists, so that the determination result
indicates not to output the images generated by the image capturing
device 10. And the output unit 106 will not output any image
generated by the image capturing device 10 (Step S512). In other
words, by the above mentioned method, the invention can
automatically recognize whether the object is moving in the image,
and allow image output when detecting movement variation of the
object. That is, the present invention can determine whether to
output the images generated by the image capturing device 10
according to the focal distance variation of the images, and
effectively improve the security of image data access.
[0069] Besides, in an embodiment, relative operations performed by
the determination unit 104 in steps S506, S506 and S508 can also be
implemented by an auto focus balance module of an image signal
processor.
[0070] In summary, in the traditional method, the captured images
are directly transmitted to the display device or the external
device for preview or storage after capturing images. In
comparison, the image capturing device 10 of the present invention
can determine whether to output the images captured by the image
capturing device 10 according to the image feature values of the
captured images at different time points. That is, the images
generated by the image capturing device 10 of the present invention
can be outputted only after determination and authentication. As
such, the present invention can effectively prevent hackers from
stealing or peeping the images generated by the image capturing
device 10 via remote control and thus enhancing the security of
image data access.
[0071] Those skilled in the art will readily observe that numerous
modifications and alterations of the device and method may be made
while retaining the teachings of the invention. Accordingly, the
above disclosure should be construed as limited only by the metes
and bounds of the appended claims.
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