U.S. patent application number 14/724804 was filed with the patent office on 2016-12-01 for transparent display apparatus and image adjustment method thereof.
The applicant listed for this patent is Chunghwa Picture Tubes, LTD.. Invention is credited to Pei-Lin Hsieh, Hsiang-Tan Lin.
Application Number | 20160351164 14/724804 |
Document ID | / |
Family ID | 57399039 |
Filed Date | 2016-12-01 |
United States Patent
Application |
20160351164 |
Kind Code |
A1 |
Hsieh; Pei-Lin ; et
al. |
December 1, 2016 |
TRANSPARENT DISPLAY APPARATUS AND IMAGE ADJUSTMENT METHOD
THEREOF
Abstract
A transparent display apparatus and an image adjustment method
thereof are provided. The image adjustment method includes
following steps. A background image information is obtained
according to a background scenery at a first side of the
transparent display panel. At least one of a plurality of color
attributes of a display image is adjusted according to the
background image information. The adjusted display image is output
at a second side of the transparent display panel.
Inventors: |
Hsieh; Pei-Lin; (Taoyuan
City, TW) ; Lin; Hsiang-Tan; (Keelung City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chunghwa Picture Tubes, LTD. |
Taoyuan City |
|
TW |
|
|
Family ID: |
57399039 |
Appl. No.: |
14/724804 |
Filed: |
May 28, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G09G 2320/0242 20130101;
G09G 5/026 20130101; G09G 2320/0666 20130101; G09G 5/006 20130101;
G06F 3/147 20130101; G09G 5/06 20130101; G09G 2320/103 20130101;
G09G 5/02 20130101; G09G 5/14 20130101; G09G 2320/066 20130101 |
International
Class: |
G09G 5/02 20060101
G09G005/02; G09G 5/06 20060101 G09G005/06; G09G 5/00 20060101
G09G005/00 |
Claims
1. An image adjustment method of a transparent display apparatus,
the transparent display apparatus comprising a transparent display
panel, the image adjustment method comprising: obtaining a
background image information according to a background scenery at a
first side of the transparent display panel; adjusting at least one
of a plurality of color attributes of a display image according to
the background image information, wherein the step of adjusting at
least one of the color attributes of the display image according to
the background image information comprises: comparing a color
difference between at least one display color of the display image
and at least one background color of the background image
information; and adjusting at least one of the color attributes of
the display image according to the color difference; and outputting
the adjusted display image at a second side of the transparent
display panel.
2. (canceled)
3. The image adjustment method of the transparent display apparatus
as claimed in claim 1, wherein the step of adjusting at least one
of the color attributes of the display image according to the color
difference comprises: comparing the color difference and a
threshold value; and adjusting at least one of the color attributes
of the display image according to a difference obtained by
comparing the color difference and the threshold value.
4. The image adjustment method of the transparent display apparatus
as claimed in claim 3, wherein the step of comparing the color
difference between the display color of the display image and the
background color of the background image information comprises:
converting the display color into a first position in a color
space; converting the background color into a second position in
the color space; and calculating a distance between the first
position and the second position in the color space to obtain the
color difference.
5. The image adjustment method of the transparent display apparatus
as claimed in claim 4, wherein the step of adjusting at least one
of the color attributes of the display image according to the
difference obtained by comparing the color difference and the
threshold value comprises: when the color difference is smaller
than the threshold value, shifting the first position for changing
at least one of the color attributes of the display color according
to the difference between the color difference and the threshold
value; and when the color difference is not smaller than the
threshold value, not changing each of the color attributes of the
display color.
6. The image adjustment method of the transparent display apparatus
as claimed in claim 1, wherein the transparent display apparatus
further comprises a background image capturing unit, and the step
of obtaining the background image information according to the
background scenery at the first side of the transparent display
panel comprises: capturing the background scenery at the first side
of the transparent display panel to generate the background image
information by the background image capturing unit.
7. The image adjustment method of the transparent display apparatus
as claimed in claim 1, wherein the color attribute comprises
saturation, contrast or lightness.
8. An image adjustment method of a transparent display apparatus,
the transparent display apparatus comprising a transparent display
panel, the image adjustment method comprising: obtaining a
background image information according to a background scenery at a
first side of the transparent display panel; comparing a display
image of a second side of the transparent display panel and the
background image information to obtain a color difference;
adjusting at least one of a plurality of color attributes of the
display image by comparing the color difference and a threshold
value; and outputting the adjusted display image at the second side
of the transparent display panel.
9. The image adjustment method of the transparent display apparatus
as claimed in claim 8, wherein the step of comparing the display
image of the second side of the transparent display panel and the
background image information to obtain the color difference
comprising: converting at least one display color of the display
image into a first position in a color space; converting at least
one background color of the background color into a second position
in the color space; and calculating a distance between the first
position and the second position in the color space to obtain the
color difference.
10. The image adjustment method of the transparent display
apparatus as claimed in claim 9, wherein the step of adjusting at
least one of the color attributes of the display image by comparing
the color difference and the threshold value comprising: when the
color difference is smaller than the threshold value, shifting the
first position for changing at least one of the color attributes of
the display color according to the difference between the color
difference and the threshold value; and when the color difference
is not smaller than the threshold value, not changing each of the
color attributes of the display color.
11. The image adjustment method of the transparent display
apparatus as claimed in claim 8, wherein the transparent display
apparatus further comprises a background image capturing unit, and
the step of obtaining the background image information according to
the background scenery at the first side of the transparent display
panel comprises: capturing the background scenery at the first side
of the transparent display panel to generate the background image
information by the background image capturing unit.
12. The image adjustment method of the transparent display
apparatus as claimed in claim 8, wherein the color attribute
comprises saturation, contrast or lightness.
13. A transparent display apparatus, comprising: a transparent
display panel, having a first side and a second side; and a
processing unit, coupled to the transparent display panel,
obtaining a background image information according to a background
scenery at the first side of the transparent display panel,
adjusting at least one of a plurality of color attributes of a
display image according to the background image information, and
outputting the adjusted display image at the second side of the
transparent display panel, wherein the processing unit compares a
color difference between at least one display color of the display
image and at least one background color of the background image
information, and adjusts at least one of the color attributes of
the display image according to the color difference.
14. (canceled)
15. The transparent display apparatus as claimed in claim 13,
wherein the processing unit compares the color difference and a
threshold value, and adjusts at least one of the color attributes
of the display image according to a difference obtained by
comparing the color difference and the threshold value.
16. The transparent display apparatus as claimed in claim 15,
wherein the processing unit converts the display color into a first
position in a color space, converts the background color into a
second position in the color space, and calculates a distance
between the first position and the second position in the color
space to obtain the color difference.
17. The transparent display apparatus as claimed in claim 16,
wherein when the color difference is smaller than the threshold
value, the processing unit shifts the first position for changing
at least one of the color attributes of the display color according
to the difference between the color difference and the threshold
value, and when the color difference is not smaller than the
threshold value, the processing unit do not change at least one of
the color attributes of the display color.
18. The transparent display apparatus as claimed in claim 13,
further comprising: a background image capturing unit, coupled to
the processing unit, capturing the background scenery at the first
side of the transparent display panel to generate the background
image information.
19. The transparent display apparatus as claimed in claim 13,
wherein the color attribute comprises saturation, contrast or
lightness.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to an image
processing technology, in particular, to a transparent display
apparatus and an image adjustment method thereof.
[0003] 2. Description of Related Art
[0004] Generally, liquid crystal displays (LCDs) can be broadly
classified into three types, namely, transmissive, reflective and
transflective LCDs. With increases in applications of the displays,
transparent display panel has been developed in recent years. The
transparent display panel has a sufficient transparency rate, and
therefore a user can look through the transparent display panel and
observe the background scenery behind the transparent display
panel. In addition to the inherent transparent display function,
the transparent display panel may also be applied as an information
display.
[0005] However, the transparency properties may lead to certain
issues. Specifically, a background scenery behind the transparent
display panel may degrade the display effects of an image displayed
on the transparent display panel. For instance, in a case of
displaying an image of a red cherry with green leaves on the
transparent display panel, it may be difficult to recognize the red
cherry when the background scenery is composed of red roses. On the
other hand, it may be difficult to recognize the green leaves when
the background scenery is composed of green lawn. Thereby, the
readability of the transparent display panel is significantly
affected by the background scenery.
SUMMARY OF THE INVENTION
[0006] Accordingly, the present invention is directed to a
transparent display apparatus and an image adjustment method
thereof, which enhances the display effects of the image displayed
on the transparent display panel, and thereby allows the user to
recognize the display image clearly.
[0007] The invention provides an image adjustment method of a
transparent display apparatus. The transparent display apparatus
includes a transparent display panel. The image adjustment method
includes the following steps. A background image information is
obtained according to a background scenery at a first side of the
transparent display panel. At least one of a plurality of color
attributes of a display image is adjusted according to the
background image information. The adjusted display image is output
at a second side of the transparent display panel.
[0008] In an embodiment of the invention, the step of adjusting at
least one of the color attributes of the display image according to
the background image information includes following steps. A color
difference between at least one display color of the display image
and at least one background color of the background image
information is compared. At least one of the color attributes of
the display image is adjusted according to the color
difference.
[0009] In an embodiment of the invention, the step of adjusting at
least one of the color attributes of the display image according to
the color difference includes following steps. The color difference
and a threshold value is compared. At least one of the color
attributes of the display image is adjusted according to a
difference obtained by comparing the color difference and the
threshold value.
[0010] In an embodiment of the invention, the step of comparing the
color difference between the display color of the display image and
the background color of the background image information includes
following steps. The display color is converted into a first
position in a color space. The background color is converted into a
second position in the color space. A distance between the first
position and the second position in the color space is calculated
to obtain the color difference.
[0011] In an embodiment of the invention, the step of adjusting at
least one of the color attributes of the display image according to
the difference obtained by comparing the color difference and the
threshold value includes following steps. When the color difference
is smaller than the threshold value, the first position is shifted
for changing at least one of the color attributes of the display
color according to the difference between the color difference and
the threshold value. When the color difference is not smaller than
the threshold value, each of the color attributes of the display
color is not changed.
[0012] In an embodiment of the invention, the transparent display
panel further includes a background image capturing unit. The step
of obtaining the background image information according to the
background scenery at the first side of the transparent display
panel includes following steps. The background scenery at the first
side of the transparent display panel is captured to generate the
background image information by the background image capturing
unit.
[0013] In an embodiment of the invention, the color attribute
includes saturation, contrast or lightness.
[0014] The invention provides another image adjustment method of a
transparent display apparatus. The transparent display apparatus
includes a transparent display panel. The image adjustment method
includes the following steps. A background image information is
obtained according to a background scenery at a first side of the
transparent display panel. A display image of a second side of the
transparent display panel and the background image information are
compared to obtain a color difference. At least one of a plurality
of color attributes of the display image is adjusted by comparing
the color difference and a threshold value. The adjusted display
image is output at the second side of the transparent display
panel.
[0015] In an embodiment of the invention, the step of comparing the
display image of the second side of the transparent display panel
and the background image information to obtain the color difference
includes following steps. At least one display color of the display
image is converted into a first position in a color space. At least
one background color of the background image is converted into a
second position in the color space. A distance between the first
position and the second position in the color space is calculated
to obtain the color difference.
[0016] In an embodiment of the invention, the step of adjusting at
least one of the color attributes of the display image by comparing
the color difference and the threshold value includes following
steps, when the color difference is smaller than the threshold
value, the first position is shifted for changing at least one of
the color attributes of the display color according to the
difference between the color difference and the threshold value.
When the color difference is not smaller than the threshold value,
each of the color attributes of the display color is not
changed.
[0017] In an embodiment of the invention, the transparent display
apparatus further includes a background image capturing unit, and
the step of obtaining the background image information according to
the background scenery at the first side of the transparent display
panel includes following step, the background scenery at the first
side of the transparent display panel is captured to generate the
background image information by the background image capturing
unit.
[0018] In an embodiment of the invention, the color attribute
includes saturation, contrast or lightness.
[0019] The invention provides a transparent display apparatus,
including a transparent display panel and a processing unit. The
transparent display panel has a first side and a second side. The
processing unit is coupled to the transparent display panel. The
processing unit obtains a background image information according to
a background scenery at the first side of the transparent display
panel, adjusts at least one of a plurality of color attributes of a
display image according to the background image information, and
outputs the adjusted display image at the second side of the
transparent display panel.
[0020] In an embodiment of the invention, the processing unit
compares a color difference between at least one display color of
the display image and at least one background color of the
background image information, and adjusts at least one of the color
attributes of the display image according to the color
difference.
[0021] In an embodiment of the invention, the processing unit
compares the color difference and a threshold value, and adjusts at
least one of the color attributes of the display image according to
a difference obtained by comparing the color difference and the
threshold value.
[0022] In an embodiment of the invention, the processing unit
converts the display color into a first position in a color space,
converts the background color into a second position in the color
space, and calculates a distance between the first position and the
second position in the color space to obtain the color
difference.
[0023] In an embodiment of the invention, when the color difference
is smaller than the threshold value, the processing unit shifts the
first position for changing at least one of the color attributes of
the display color according to the difference between the color
difference and the threshold value. When the color difference is
not smaller than the threshold value, the processing unit do not
change each of the color attributes of the display color.
[0024] In an embodiment of the invention, the transparent display
apparatus further includes a background image capturing unit, which
is coupled to the processing unit. The background image capturing
unit captures the background scenery at the first side of the
transparent display apparatus to generate the background image
information.
[0025] In an embodiment of the invention, the color attributes
comprises saturation, contrast and lightness.
[0026] Based on the above, the transparent display apparatus and
the image adjustment method thereof disclosed by the embodiments of
the invention adaptively adjusts at least one of the color
attributes of the display image according to the background image
information. Thereby, the color difference between the display
image and the background image may be increased for easy
recognition and further enhance readability of the display image on
the transparent display panel.
[0027] In order to make the aforementioned and other features and
advantages of the invention more comprehensible, embodiments
accompanying figures are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0029] FIG. 1 is a block diagram illustrating a transparent display
apparatus according to an embodiment of the invention.
[0030] FIG. 2 is a schematic diagram illustrating a transparent
display apparatus according to an embodiment of the invention.
[0031] FIG. 3 is a flow chart illustrating an image adjustment
method of a transparent display apparatus according to an
embodiment of the invention.
[0032] FIG. 4 is a flow chart illustrating an image adjustment
method of a transparent display apparatus according to another
embodiment of the invention.
[0033] FIG. 5 is a schematic diagram illustrating a color space
according to an embodiment of the invention.
[0034] FIG. 6 is a schematic diagram illustrating a calculation of
a color difference according to the embodiment of FIG. 5.
[0035] FIG. 7A, FIG. 7B and FIG. 7C are schematic diagrams
respectively illustrating an image adjustment method based on the
color space according to the embodiment of FIG. 5 and FIG. 6.
[0036] FIG. 8 is a flow chart illustrating an image adjustment
method of a transparent display apparatus according to another
embodiment of the invention.
DESCRIPTION OF THE EMBODIMENTS
[0037] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0038] For a transparent display apparatus, when a display color of
a display image displayed on the transparent display apparatus and
a background color of a background scenery behind the transparent
display apparatus are similar, it may be difficult for a user to
recognize the display image clearly. In order to solve the problem,
the embodiments of the present invention determine whether the
display color is recognizable with respect to the background color
by analyzing a color difference between the display color and the
background color. When the color difference is too small and thus
the display color is hard to be recognized, the embodiments of the
present invention may adaptively adjust at least one color
attribute of the display color to increase the color difference.
Therefore, the display effects of the display image may be
enhanced, and the user may recognize the display image clearly.
[0039] FIG. 1 is a block diagram illustrating a transparent display
apparatus according to an embodiment of the invention. Referring to
FIG. 1, the transparent display apparatus 100 includes a
transparent display panel 110, a processing unit 120 and a
background image capturing unit 130, where the functionalities
thereof are given as follows.
[0040] The transparent display panel 110 may be characterized by
transparency, such as a liquid crystal display (LCD) panel or an
organic light-emitting diode (OLED) display panel. The transparent
display panel 110 may have a first side S1 and a second side S2. In
the present embodiment, the first side S1 may correspond to the
side closer to the background scenery (e.g. the back of the
transparent display panel 110), while the second side S2 may
correspond to the side closer to the user for displaying (e.g. the
front of the transparent display panel 110).
[0041] The processing unit 120 may be, for example, a single chip,
a general-purpose processor, a special-purpose processor, a
traditional processor, a digital signal processor (DSP), a
plurality of microprocessors, or one or more microprocessors,
controllers, microcontrollers, application specific integrated
circuit (ASIC), or field programmable gate arrays (FPGA) with a DSP
core. In the present embodiment, the processing unit 120 is
configured to implement the proposed method for adjusting the image
displayed on the transparent display panel 110.
[0042] The background image capturing unit 130, for example, can
include fixed focus optical lens or optical zoom lens, and a
photosensitive element, such as a charge coupled device (CCD) or
complementary metal-oxide semiconductor (CMOS). The background
image capturing unit 130 is coupled to the processing unit 120. In
the present embodiment, the background image capturing unit 130 may
capture the background scenery at the first side S1 of the
transparent display panel 110 to generate the background image
information. For example, when the first side S1 is the back of the
transparent display panel 110, the background image capturing unit
130 may be set toward the back of the transparent display panel 110
for directionally capturing the background scenery behind the
transparent display panel 110.
[0043] Moreover, the transparent display apparatus 100 may also
include a storage unit 140, and yet the invention is not limited
herein. The storage unit 140 is configured to store data and
accessible by the processing unit 120. The storage unit 140 may be,
for example, a hard disk drive (HDD), a volatile memory, or a
non-volatile memory.
[0044] FIG. 2 is a schematic diagram illustrating a transparent
display apparatus according to an embodiment of the invention,
which illustrates an exemplary configuration of the aforementioned
components in the transparent display apparatus 100. It should be
noted that, for convenience, only the transparent display panel 110
and the background image capturing unit 130 of the transparent
display apparatus 100 are illustrated in FIG. 2.
[0045] Referring to FIG. 2, a user 200 may be located in front of
the transparent display apparatus 100 and watch the display image
displayed on the transparent display panel 110. In the present
embodiment, the processing unit 120 may output the display image at
the front side (i.e. the second side S2) of the transparent display
panel 110.
[0046] In addition, a background scenery at the back side (i.e. the
first side S1) of the transparent display panel 110 may be visible
to the user 200 due to the high transparency rate of the
transparent display apparatus 100. In order to capturing the
background scenery conveniently to generate the background image
information, the background image capturing unit 130 may be
configured to the back side of the transparent display apparatus
100. In the present embodiment, the background image capturing unit
130 may be set at the upper-left of the transparent display
apparatus 100. However, the invention is not intended to limit the
configuration of the background image capturing unit 130 in the
transparent display apparatus 100. Thereby, based on the above
device architecture, the present embodiment may adjust the display
image and then output the adjusted display image to display at the
second side S2 of the transparent display panel 110 in
consideration of the influence from the background image
information, so as to enhance the readability of the display image
displayed on the transparent display panel 110.
[0047] It is worth mentioning that, in the embodiment of FIG. 2,
the first side S1 and the second side S2 of the transparent display
panel 110 may be utilized for described the relative position among
the display image and the background image. In other embodiment,
the first side S1 and the second side S2 may be adaptively used to
indicate other regions of the transparent display panel 110
respectively, depending on the position where the display image is
outputted, and the invention is not intend to limit thereto.
[0048] FIG. 3 is a flow chart illustrating an image adjustment
method of a transparent display apparatus according to an
embodiment of the invention, which is adapted to the transparent
display apparatus 100 in FIG. 1 and FIG. 2. Detailed steps of the
proposed method will be illustrated along with the components of
the transparent display apparatus 100 hereafter.
[0049] Referring to FIG. 1 to FIG. 3, in Step S310, the processing
unit 120 obtains a background image information according to a
background scenery at a first side S1 of the transparent display
panel 110. In the present embodiment, the background image
information may be generated by the background image capturing unit
130, as described above. The background image information may
include one or more background colors in the background scenery.
Besides, the background image information may also include location
information of the background color in the background scenery.
[0050] In Step S320, the processing unit 120 adjusts at least one
of a plurality of color attributes of a display image according to
the background image information. In Step S330, the processing unit
120 outputs the adjusted display image at a second side S2 of the
transparent display panel 110. The color attribute may include, for
example, saturation, contrast or lightness.
[0051] Specifically, in an embodiment, the processing unit 120 may
compare a color difference between at least one display color of
the display image and at least one background color of the
background image information, and then may adjust at least one of
the color attributes of the display image according to the color
difference. Further, the processing unit 120 may compare the color
difference and a threshold value, and adjust at least one of the
color attributes of the display image according to a difference
obtained by comparing the color difference and the threshold
value.
[0052] Taking the display image including one display color for
instance, the processing unit 120 may analyze the background image
information, determine a region overlapped with the display image,
and then obtain the background color depending on the color of the
overlapped region. Then, the processing unit 120 may use
coordinates defined by a color space to represent the display color
and the background color respectively, and then calculate the color
difference based on the color space.
[0053] In the present embodiment, a threshold value is used for
determining whether the color difference may be recognized by the
user 200. Specifically, the threshold value may be a minimal color
variation that can be sensed by human eyes. More particularly, the
threshold value may be, for example, a just-noticeable difference
(IND). Therefore, when the color difference does not satisfy the
threshold value, the processing unit 120 may calculate a difference
between the color difference and the threshold value, and use the
difference between the color difference and the threshold value to
adjust at least one of saturation, contrast and lightness (i.e. the
color attributes) of the display image, so as to make the display
color recognizable with respect to the background color for the
user 200.
[0054] Accordingly, the present embodiment may determine to adjust
the output display image on the second side S2 of the transparent
display panel 110 according to the background scenery at the first
side S1 of the transparent display panel 110, in particular,
according to the color difference between the display color and the
background color. Thereby, the adjusted display image may be easily
recognized by the user 200, and the display effects of the display
image may be improved.
[0055] It should be noted that although the aforementioned
embodiment merely illustrates the case of one display color
included in the display image, the case of multiple display color
included in the display image may also be adapted.
[0056] FIG. 4 is a flow chart illustrating an image adjustment
method of a transparent display apparatus according to another
embodiment of the invention, which is also adapted to the
transparent display apparatus 100 in FIG. 1 and FIG. 2.
[0057] Referring to FIG. 4, in Step S410, the processing unit 120
obtains a background image information according to a background
scenery at a first side S1 of the transparent display panel 110.
Step S410 may be similar to Step S310 of the embodiment in FIG. 3,
so the details are not mentioned here.
[0058] In Step S420, the processing unit 120 compares a display
image of a second side S2 of the transparent display panel 110 and
the background image information to obtain a color difference.
Specifically, the processing unit 120 may respectively execute a
color-space conversion operation to convert at least one display
color of the display image and at least one background color of the
background image information into in a same color-space to
calculate the color difference. For instance, the processing unit
120 may convert the display color into a first position in a color
space and convert the background color into a second position in
the color space. Then, the processing unit 120 may calculate a
distance between the first position and the second position in the
color space to obtain the color difference. The color space may be
two dimensional or three dimensional, where the invention is not
intend to limit thereto.
[0059] The following is an example as shown in FIG. 5 and FIG. 6.
FIG. 5 is a schematic diagram illustrating a color space according
to an embodiment of the invention, and FIG. 6 is a schematic
diagram illustrating a calculation of a color difference according
to the embodiment of FIG. 5. Referring to FIG. 5, a color space 500
may be, for instance, L*a*b* color space, which is formed with
dimension L represented for lightness and dimensions a and b
represented for color. In the color space 500, the a* axis with a
values from -500 to 500 may be used for illustrating the red/green
opponent colors, where the negative a (e.g. -a) values may be
represented for green and the positive a (e.g. +a) values may be
represented for red. In addition, the b* axis with b values from
-200 to 200 may be used for illustrating the yellow/blue opponent
colors, where the negative b (e.g. -b) values may be represented
for blue and the positive b (e.g. +b) values may be represented for
yellow. Besides, the L* axis with L values from 0 to 100 may be
used for illustrating the darkest black and brightness white. It is
worthy mentioning that a unit length of the a* axis, a unit length
of the b* axis and a unit length of the L axis may be different,
where the unit length of the a* axis indicates a distance between
two continuous integers on the a* axis, the unit length of the b*
axis indicates a distance between two continuous integers on the b*
axis, and the unit length of the L* axis indicates a distance
between two continuous integers on the L* axis. Based on the above,
the processing unit 120 may use each of positions in the color
space 500 for indicating a particular color.
[0060] Next, referring to FIG. 6, the color space 500 may also be
represented by a two-dimensional depiction 510 for a chromaticity
diagram and a one-dimensional depiction 520 for the lightness
diagram. When the processing unit 120 converts the display color
into the position P1 (expressed as (L.sub.1, a.sub.1, b.sub.1)) in
the color space 500, and converts the background color into the
position P2 (expressed as (L.sub.2, a.sub.2, b.sub.2)) in the color
space 500, a distance D between the position P1 and P2 may be
treated as the color difference between the display color and the
background color. In the present embodiment, the distance D may be
calculated by an equation (1):
D=(.DELTA.L.sup.2+.DELTA.a.sup.2+.DELTA.b.sup.2).sup.1/2, where
.DELTA.L=L.sub.1-L.sub.2, .DELTA.a=a.sub.1-a.sub.2, and
.DELTA.b=b.sub.1-b.sub.2. Then, the processing unit 120 may use the
distance D to determine whether the display color is easily
recognized by human eyes respective to the background color.
[0061] Referring to FIG. 4 again, in Step S430, the processing unit
120 determines whether the color difference is smaller than a
threshold value. Similar to the aforementioned embodiments, the
threshold value may be the minimal color variation that can be
sensed by human eyes. Particularly, the threshold value may be
determined based on the utilized color space. In the case of the
L*a*b* color space, the minimal color variation (i.e. the
just-noticeable difference) may be a value of 3, based on a unit of
color difference qualified by National Bureau of Standard (NBS).
Hence, the threshold value may be set as 3 in the present
embodiment.
[0062] It should be noticed that the color spaces may also be, for
example, RGB color space, xyY color space, or XYZ color space, and
therefore the threshold value may be adaptively changed with
different color spaces.
[0063] Please continue the flow illustrated in FIG. 4, when the
color difference is smaller than the threshold value, in Step S440,
the processing unit 120 adjusts at least one of the color
attributes of the display image according to a difference between
the color difference and the threshold value. Specifically, the
processing unit 120 may adjust at least one of the color attributes
of the display image based on the dimensions of the color space.
Taking the color space 500 in FIG. 5 and FIG. 6 as an example, the
processing unit 120 may shift the position P1 to increase the
distance D between the position P1 and P2, so as to increase the
color difference between the display color and the background
color. Since the color space 500 may be formed with the dimensions
of lightness and chromaticity, the processing unit 120 may execute
the aforementioned shifting operation to shift the position P1 for
changing at least one of lightness, saturation and contrast of the
display color. Three examples are respectively illustrated in FIG.
7A, FIG. 7B and FIG. 7C as follows.
[0064] FIG. 7A, FIG. 7B and FIG. 7C are schematic diagrams
respectively illustrating an image adjustment method based on the
color space according to the embodiment of FIG. 5 and FIG. 6. For
convenience to illustrate the adjustment of the display color when
the color difference is smaller than the threshold value, only the
position P1 converted from the display color is shown in FIG. 7A,
FIG. 7B and FIG. 7C. However, it may be understood that the
position P2 may be closed to the position P1 in these
embodiments.
[0065] Referring to the embodiment illustrated in FIG. 7A at first,
since the position P1 is on the a* axis with +a value, the
processing unit 120 may change the saturation of the display color
by shifting the position P1 within a range between the a value from
0 (i.e. center C) to +500 on the a* axis. For instance, the
processing unit 120 may shift the position P1 to the position oP1
or the position oP2. It should be noted that the distance between
the position P1 and the position oP1 and the distance between the
position P1 and the position oP2 may be both greater than the
threshold value. Since the present embodiment in FIG. 7A may change
the saturation of the display color by merely shifting the position
P1 within the range of +a values on the a* axis rather than change
the hue of the display color, the image adjustment method disclosed
by the embodiment in FIG. 7A may be applied to, for example,
natural images.
[0066] FIG. 7B illustrates an embodiment of the image adjustment
method by changing the contrast of the display color. Since the
opponent colors are represented along each of the axes in the color
space 500, the processing unit 120 may change the contrast of the
display color by shifting the position P1 to the opposite position
with respect to the center C. For instance, the processing unit 120
may shift the position P1 to the position oP3, where the position
oP3 may be within -a value from 0 to -500 on the a* axis.
Similarly, the distance between the position P1 and the position
oP3 should be greater than the threshold value. With respect to the
saturation adjustment without changing the hue of the display image
in the embodiment in FIG. 7A, the present embodiment in FIG. 7B may
change the contrast of the display color, so as to change the hue
of the display color, and may be particularly applied to text
images accordingly.
[0067] In addition, the processing unit 120 may adjust the display
image by changing the lightness of the display color. Referring to
the embodiment illustrated in FIG. 7C, the processing unit 120 may
change the lightness of the display color by shifting the position
P1 by changing to different L values. For instance, the processing
unit 120 may shift the position P1 upwards to the position oP4 to
raise the lightness of the display color. Alternatively, the
processing unit 120 may also shift the position P1 downwards to the
position oP5 to lower the lightness of the display color. Through
the present embodiment in FIG. 7C, the color difference between the
display color and the background color may be increased by making
the outline or the shape of the display image clear, and thereby
the present embodiment may be applied to a low-light
environment.
[0068] In the embodiments in FIG. 7A to FIG. 7C, the position P1
may be with the +a value on the a* axis for convenient description.
However, other positions in the color space 500 may also be adapted
to the adjustment methods disclosed by the embodiments in FIG. 7A
to FIG. 7C. In addition, It is worth mentioning that the adjustment
methods disclosed by the embodiments in FIG. 7A to FIG. 7C may be
combined to use depending on design requirements, and thus the
invention is not intend to limit thereto.
[0069] Referring to FIG. 4 again, in Step S450, the processing unit
120 outputs the adjusted display image at a second side S2 of the
transparent display panel 110. Step S450 may be similar to Step
S330 of the embodiment in FIG. 3, so the details are not mentioned
here.
[0070] On the other hand, when the color difference is not smaller
than the threshold value, that is, the display image may be
recognized clearly, the processing unit 120 may not change each of
the color attributes of the display color. Therefore, in Step S460,
the processing unit 120 outputs the display image without image
adjustment at the second side S2 of the transparent display panel
110.
[0071] Accordingly, the aforementioned embodiments may execute the
color-space conversion operation to calculate the color difference
between the display image and the background image. Further,
whether to adjust the display color of the display image may be
determined according to the color difference. Besides, the applied
environment or the type of the display image may be also considered
to determine that which one of the color attributes of the display
color is adjusted, so as to increase the color difference and
provide good display effects.
[0072] FIG. 8 is a flow chart illustrating an image adjustment
method of a transparent display apparatus according to another
embodiment of the invention, which is also adapted to the
transparent display apparatus 100 in FIG. 1 and FIG. 2. Besides,
the color space 500 disclosed by the embodiments in FIG. 5 and FIG.
6 is utilized in the present embodiment.
[0073] Referring to FIG. 8, in Step S810, the processing unit 120
obtains a background image information according to a background
scenery at a first side S1 of the transparent display panel 110.
Step S810 in the present embodiment is similar to Step S310 and
Step 410, and thus the details are not mentioned here.
[0074] In Step S820, the processing unit 120 obtains a display
image. In an embodiment, the processing unit 120 may use at least
one image information to drive the transparent display panel 110 to
display. In other words, the processing unit 120 may obtain the
display image and the display color through the image
information.
[0075] In Step S830, the processing unit 120 executes a color-space
conversion operation to respectively convert the display color and
the background color into the position P1 and P2. In Step S840, the
processing unit 120 calculates a distance D between the position P1
and P2 in the color space 500 to obtain a color difference. The
Steps S830 and S840 have been described in detail in the
embodiments of FIG. 5 and FIG. 6, so the details are not mentioned
here.
[0076] Then, in Step S850, the processing unit 120 determines
whether the color difference is smaller than a threshold value.
When the color difference is smaller than the threshold value, in
Step S860, the processing unit 120 shifts the position P1 for
changing at least one of the color attributes of the display color.
The processing unit 120 may adjusting at least one of saturation,
contrast and lightness of the display color with reference to the
embodiments in FIG. 7A, FIG. 7B and FIG. 7C, so the details are not
mentioned here.
[0077] Afterwards, the processing unit 120 outputs the adjusted
display image at a second side S2 of the transparent display panel
110 in Step S870.
[0078] As for the case that the color difference is not smaller
than the threshold value, the processing unit 120 may not change
each of the color attributes of the display color, and then output
the display image without image adjustment at the second side S2 of
the transparent display panel 110 in Step S880. Step S880 may be
similar to the Step S460 of the embodiment in FIG. 4, so the
details are not mentioned here.
[0079] To conclude the above, the embodiments disclosed by the
invention may adjust at least one of the color attributes of the
display image based on the color difference between the display
color and the background color, and the color difference may be
calculated through executing the color-space conversion operation.
Besides, the applied environment is also considered. Accordingly,
good display effects of the transparent display apparatus may be
provided in consideration of the background scenery, the display
image may be recognized easily, and therefore the readability of
the display image may be enhanced.
[0080] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
* * * * *