U.S. patent application number 14/706158 was filed with the patent office on 2016-03-24 for real-time color mapping system and method.
The applicant listed for this patent is DELTA ELECTRONICS, INC., National Central University. Invention is credited to Keh-Su CHANG, Yu-Ta CHEN, Ting-Wei HUANG, Jyun-Wei JHUANG, Mang OU-YANG.
Application Number | 20160086573 14/706158 |
Document ID | / |
Family ID | 53937900 |
Filed Date | 2016-03-24 |
United States Patent
Application |
20160086573 |
Kind Code |
A1 |
CHANG; Keh-Su ; et
al. |
March 24, 2016 |
REAL-TIME COLOR MAPPING SYSTEM AND METHOD
Abstract
A real-time color mapping system includes a memory and a
converting module. The memory is configured for storing a mapping
table. The converting module is configured for reading the mapping
table stored in the memory, and for converting first image
grayscale values corresponding to a first image signal into second
image grayscale values corresponding to a second image signal
according to the mapping table. The converting module utilizes at
least part of bits corresponding to each of the first image
grayscale values as a memory address to look up in the mapping
table, thereby converting the first image grayscale values into the
second image grayscale values. A real-time color mapping method is
provided herein as well.
Inventors: |
CHANG; Keh-Su; (Taoyuan
City, TW) ; OU-YANG; Mang; (Hsinchu City, TW)
; HUANG; Ting-Wei; (Taipei City, TW) ; JHUANG;
Jyun-Wei; (Hsinchu City, TW) ; CHEN; Yu-Ta;
(Taoyuan City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DELTA ELECTRONICS, INC.
National Central University |
Taoyuan City
Taoyuan City |
|
TW
TW |
|
|
Family ID: |
53937900 |
Appl. No.: |
14/706158 |
Filed: |
May 7, 2015 |
Current U.S.
Class: |
345/590 |
Current CPC
Class: |
H04N 1/644 20130101;
G09G 5/06 20130101; G09G 2340/06 20130101; H04N 9/67 20130101; H04N
1/62 20130101; G09G 2320/0673 20130101 |
International
Class: |
G09G 5/06 20060101
G09G005/06; G09G 5/02 20060101 G09G005/02; H04N 9/69 20060101
H04N009/69; G06T 15/04 20060101 G06T015/04; G06T 7/40 20060101
G06T007/40 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 23, 2014 |
TW |
103132698 |
Claims
1. A real-time color mapping system, comprising: a memory
configured to store a mapping table; and a converting module
configured to read the mapping table stored in the memory, and to
convert a plurality of first image grayscale values corresponding
to a first image signal into a plurality of second image grayscale
values corresponding to a second image signal according to the
mapping table, wherein the converting module utilizes at least part
of bits corresponding to each of the first image grayscale values
as a memory address to look up in the mapping table, thereby
converting the first image grayscale values into the second image
grayscale values.
2. The real-time color mapping system of claim 1, wherein the
converting module utilizes all of the bits corresponding to each of
the first image grayscale values as the memory address to look up
in the mapping table, thereby converting the first image grayscale
values into the second image grayscale values.
3. The real-time color mapping system of claim 1, wherein each of
the first image grayscale values includes n first pixel grayscale
values with different colors, and each of the n first pixel
grayscale values is represented by m bits, and the converting
module utilizes n.times.(m-i) bits corresponding to each of the
first image grayscale values as the memory address to look up in
the mapping table, where n>1 and m>i.gtoreq.1.
4. The real-time color mapping system of claim 3, wherein the (m-i)
bits corresponding to each of the n first pixel grayscale values
are the highest (m-i) bits.
5. The real-time color mapping system of claim 3, wherein each of
the second image grayscale values includes n corresponding second
pixel grayscale values, and each of the n second pixel grayscale
values is represented by m bits, and the converting module converts
the n.times.(m-i) bits of each of the first image grayscale values
into corresponding n.times.(m-i) bits of each of the second image
grayscale values according to a look-up result.
6. The real-time color mapping system of claim 5, wherein the
converting module is further configured to integrate n.times.i
un-converted bits and the corresponding n.times.(m-i) converted
bits of each of the first image grayscale values to generate the
second image grayscale values.
7. The real-time color mapping system of claim 5, wherein the (m-i)
bits corresponding to each of the n second pixel grayscale values
are the highest (m-i) bits.
8. The real-time color mapping system of claim 5, wherein the
lowest i bits of each of the n second pixel grayscale values are
the same as the lowest i bits of each corresponding pixel grayscale
value of the n first pixel grayscale values.
9. The real-time color mapping system of claim 1, wherein the
converting module is further configured to determine whether any of
the first image grayscale values to be converted is within an image
grayscale value range; and when the first image grayscale value to
be converted is not within the image grayscale value range, the
converting module sets a corresponding second image grayscale value
of the second image grayscale values to be the same as the first
image grayscale value to be converted.
10. The real-time color mapping system of claim 9, wherein each of
the first image grayscale values includes n first pixel grayscale
values with different colors, and the converting module determines
whether the first image grayscale value to be converted is within
the image grayscale value range according to whether the n first
pixel grayscale values of the first image grayscale value to be
converted are within corresponding pixel grayscale value
ranges.
11. The real-time color mapping system of claim 1, further
comprising: a first storage unit electrically connected with the
converting module, wherein the first storage unit is configured to
store first image data of the first image signal, and the first
image data comprise the first image grayscale values; and a second
storage unit electrically connected with the converting module,
wherein the second storage unit is configured to store second image
data of the second image signal, and the second image data comprise
the second image grayscale values.
12. A real-time color mapping method, comprising: reading a mapping
table stored in a memory; and utilizing at least part of bits
corresponding to each of a plurality of first image grayscale
values corresponding to a first image signal as a memory address to
look up in the mapping table, thereby converting the first image
grayscale values into a plurality of second image grayscale values
corresponding to a second image signal.
13. The real-time color mapping method of claim 12, wherein the
operation of utilizing the at least part of bits corresponding to
each of the first image grayscale values as the memory address to
look up in the mapping table utilizes all of the bits corresponding
to each of the first image grayscale values as the memory address
to look up in the mapping table.
14. The real-time color mapping method of claim 12, wherein each of
the first image grayscale values includes n first pixel grayscale
values with different colors, and each of the n first pixel
grayscale values is represented by m bits, and the operation of
utilizing the at least part of bits corresponding to each of the
first image grayscale values as the memory address to look up in
the mapping table utilizes n.times.(m-i) bits corresponding to each
of the first image grayscale values as the memory address to look
up in the mapping table, wherein n>1 and m>i.gtoreq.1.
15. The real-time color mapping method of claim 14, wherein the
(m-i) bits corresponding to each of the n first pixel grayscale
values are the highest (m-i) bits.
16. The real-time color mapping method of claim 14, wherein each of
the second image grayscale values includes n corresponding second
pixel grayscale values, and each of the n second pixel grayscale
values is represented by m bits, and the operation of utilizing the
n.times.(m-i) bits corresponding to each of the first image
grayscale values as the memory address to look up in the mapping
table to convert the first image grayscale values into the second
image grayscale values further comprises: converting the
n.times.(m-i) bits of each of the first image grayscale values into
corresponding n.times.(m-i) bits of each of the second image
grayscale values according to a look-up result.
17. The real-time color mapping method of claim 16, wherein the
operation of utilizing the n.times.(m-i) bits corresponding to each
of the first image grayscale values as the memory address to look
up in the mapping table to convert the first image grayscale values
into the second image grayscale values further comprises:
integrating n.times.i un-converted bits and the corresponding
n.times.(m-i) converted bits of each of the first image grayscale
values to generate the second image grayscale values.
18. The real-time color mapping method of claim 16, wherein the
(m-i) bits corresponding to each of the n second pixel grayscale
values are the highest (m-i) bits.
19. The real-time color mapping method of claim 16, wherein the
lowest i bits of each of the n second pixel grayscale values are
the same as the lowest i bits of each corresponding pixel grayscale
value of the n first pixel grayscale values.
20. The real-time color mapping method of claim 12, wherein the
operation of utilizing the at least part of bits corresponding to
each of the first image grayscale values as the memory address to
look up in the mapping table to convert the first image grayscale
values into the second image grayscale values further comprises:
determining whether any of the first image grayscale values to be
converted is within an image grayscale value range, wherein when
the first image grayscale value to be converted is not within the
image grayscale value range, a corresponding second image grayscale
value of the second image grayscale values is set to be the same as
the first image grayscale value to be converted.
21. The real-time color mapping method of claim 20, wherein each of
the first image grayscale values includes n different-color first
pixel grayscale values, and the operation of determining whether
the first image grayscale value to be converted is within the image
grayscale value range is performed according to whether the n first
pixel grayscale values of the first image grayscale value to be
converted are within corresponding pixel grayscale value
ranges.
22. The real-time color mapping method of claim 12, further
comprising: utilizing a first storage unit to store first image
data of the first image signal, wherein the first image data
comprise the first image grayscale values; and utilizing a second
storage unit to store second image data of the second image signal,
wherein the second image data comprise the second image grayscale
values.
Description
RELATED APPLICATIONS
[0001] This application claims priority to Taiwan Application
Serial No. 103132698, filed Sep. 23, 2014, the entirety of which is
herein incorporated by reference.
BACKGROUND
[0002] 1. Technical Field
[0003] The present disclosure relates to a real-time color mapping
system. More particularly, the present disclosure relates to a
real-time color mapping system and a real-time color mapping method
for performing color mappings by looking up in a mapping table.
[0004] 2. Description of Related Art
[0005] With the development of information technology, the
applications of display devices are more and more popular. The
prices of display devices are getting lower, and the performance of
display devices is getting better. Common display devices include
LCD displays, LED displays, plasma displays and projectors. When
the abovementioned display devices are utilized to display an input
image signal (the input image signal can be generated by an
electronic system such as a media player, a computer system or a
handheld electronic device), the display devices usually need to
perform real-time color mappings on the input image signal, so as
to display the contents corresponding to the input image signal
with more precise or optimized colors.
[0006] A conventional real-time color mapping method includes
performing color mappings by using gamma curve adjustments.
However, the color mappings based on the gamma curve adjustments
are not precise enough. Also, it is not easy to perform some
specific color mappings on some specific color ranges. Therefore,
it is a very important topic in this area to design a more precise
real-time color mapping system with more freedom on
conversions.
SUMMARY
[0007] In one aspect, the present disclosure is related to a
real-time color mapping system. The real-time color mapping system
includes a memory and a converting module. The memory is configured
for storing a mapping table. The converting module is configured
for reading the mapping table stored in the memory, and for
converting a plurality of first image grayscale values
corresponding to a first image signal into a plurality of second
image grayscale values corresponding to a second image signal
according to the mapping table. The converting module utilizes at
least part of bits corresponding to each of the first image
grayscale values as a memory address to look up in the mapping
table, thereby converting the first image grayscale values into the
second image grayscale values
[0008] In another aspect, the present disclosure is related to a
real-time color mapping method. The real-time color mapping method
includes: reading a mapping table stored in a memory; and utilizing
at least part of bits corresponding to each of a plurality of first
image grayscale values corresponding to a first image signal as a
memory address to look up in the mapping table, thereby converting
the first image grayscale values into a plurality of second image
grayscale values corresponding to a second image signal.
[0009] In the present disclosure, by utilizing the grayscale values
of image signals as the memory address to look up in the mapping
table, a fast and real-time color mapping between image signals can
be performed. Compared with conventional methods (e.g., color
mappings based on gamma curve adjustments), the color mapping
disclosed in the present disclosure is more precise and provides
more freedom on adjustments. The present disclosure also discloses
utilizing only a part of bits corresponding to image grayscale
values as the memory address to look up in the mapping table.
Consequently, the memory space in the memory required to save the
mapping table can be greatly reduced. Also, the continuity of the
grayscale values can be effectively kept in the converted image
signals. In one embodiment of the present disclosure, a near 24
bits color mapping can be performed by utilizing a mapping table
occupying only 42 M bits of memory space. Therefore, the memory
required for color mappings can be reduced, and the speed of color
mappings can be improved without affecting the effects of color
displaying.
[0010] Moreover, the present disclosure also discloses determining
whether the table look-up operation on a first image grayscale
value is performed by checking whether the first image grayscale
value to be converted is within an image grayscale value range.
Consequently, the memory space in the memory required to save the
mapping table can again be effectively reduced. Moreover, by
setting the abovementioned image grayscale value range, color
mappings for some specific color ranges can be realized.
[0011] These and other features, aspects, and advantages of the
present disclosure will become better understood with reference to
the following description and appended claims.
[0012] It is to be understood that both the foregoing general
description and the following detailed description are by examples,
and are intended to provide further explanation of the disclosure
as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The disclosure can be more fully understood by reading the
following detailed description of the embodiment, with reference
made to the accompanying drawings as follows:
[0014] FIG. 1 is a schematic diagram of a real-time color mapping
system in accordance with one embodiment of the present
disclosure;
[0015] FIG. 2 is a schematic diagram illustrating conversion
between one of first image grayscale values and a corresponding one
of second image grayscale values;
[0016] FIG. 3 is a schematic diagram illustrating conversion
between one of the first image grayscale values and a corresponding
one of the second image grayscale values;
[0017] FIG. 4 is a flow chart of a real-time color mapping method
in accordance with one embodiment of the present disclosure;
and
[0018] FIG. 5 is a flow chart of a real-time color mapping method
in accordance with one embodiment of the present disclosure.
DETAILED DESCRIPTION
[0019] Reference will now be made in detail to the present
embodiments of the disclosure, 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.
[0020] Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms, such
as those defined in commonly used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein.
[0021] In the following description and claims, the terms "coupled"
and "connected", along with their derivatives, may be used. In
particular embodiments, "connected" and "coupled" may be used to
indicate that two or more elements are in direct physical or
electrical contact with each other, or may also mean that two or
more elements may be in indirect contact with each other. "Coupled"
and "connected" may still be used to indicate that two or more
elements cooperate or interact with each other.
[0022] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
the invention. As used herein, the singular forms "a", "an" and
"the" are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising", or "includes"
and/or "including" or "has" and/or "having" when used in this
specification, specify the presence of stated features, regions,
integers, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, regions, integers, steps, operations, elements,
components, and/or groups thereof.
[0023] It will be understood that, although the terms first,
second, third etc. may be used herein to describe various elements,
components, regions, layers and/or sections, these elements,
components, regions, layers and/or sections should not be limited
by these terms. These terms are only used to distinguish one
element, component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section without
departing from the teachings of the present invention.
[0024] Reference is first made to FIG. 1. FIG. 1 is a schematic
diagram of a real-time color mapping system 100 in accordance with
one embodiment of the present disclosure. The real-time color
mapping system 100 can be implemented on a display device (e.g., a
projector, a TV, a screen or a wide color gamut display), and
perform color mappings on a first image signal 203 to generate a
second image signal 223, but is not limited thereto. The first
image signal 203 can be generated by a media player (e.g., a DVD
player, a VCD player or a blue-ray disc player), a computer system
(e.g., a desktop computer or a laptop computer) or a handheld
electronic device (e.g., a smart phone or a tablet computer). The
first image signal 203 can also be generated by an optic measuring
device (e.g., a colorimeter, a luminometer or a brightness meter).
The first image signal 203 can be a high definition multimedia
interface (HDMI) signal, but is not limited thereto.
[0025] The real-time color mapping system 100 includes a memory 110
and a converting module 120. According to one embodiment of the
present disclosure, the memory 110 can be a static random access
memory (SRAM), but is not limited thereto. The converting module
120 can be an electric chip, but is not limited thereto. In another
embodiment of the present disclosure, the real-time color mapping
system 100 includes a memory unit and one or more processors. The
converting module 120 is stored in the memory unit and is executed
by the one or more processors.
[0026] In an embodiment of the present disclosure, the real-time
color mapping system 100 optionally includes a first storage unit
210 and a second storage unit 220, in which the first storage unit
210 and the second storage unit 220 are electrically connected with
the converting module 120. In another embodiment of the present
disclosure, the first storage unit 210 and the second storage unit
220 can be a double data rate synchronous dynamic random access
memory (DDR RAM), but is not limited thereto.
[0027] The memory 110 is configured for storing a mapping table
(not shown). The converting module 120 is configured for reading
the mapping table stored in the memory 110, and for converting
first image grayscale values V corresponding to the first image
signal 203 into second image grayscale values Vc corresponding to a
second image signal 223 according to the mapping table. The
converting module 120 utilizes at least part of bits V'
corresponding to each of the first image grayscale values V as a
memory address to look up in the mapping table. The first image
grayscale values V are converted into the second image grayscale
values Vc according to a look-up result Vc'.
[0028] In one embodiment of the present disclosure, the first
storage unit 210 is configured for storing first image data (not
shown) of the first image signal 203. The first image data include
the first image grayscale values V. The second storage unit 220 is
configured for storing second image data (not shown) of the second
image signal 223. The second image data include the second image
grayscale values Vc. Further, the converting module 120 enables the
color mapping between the first image data and the second image
data to be performed by converting the first image grayscale values
V into the second image grayscale values Vc.
[0029] In one embodiment of the present disclosure, the converting
module 120 utilizes all of the bits corresponding to each of the
first image grayscale values V as the memory address to look up in
the mapping table, such that the first image grayscale values V are
converted into the second image grayscale values Vc. In other
words, V' are all of the bits corresponding to the first image
grayscale values V, and Vc' are all of the bits corresponding to
the second image grayscale values Vc. Further, the converting
module 120 utilizes each of the first image grayscale values V as a
memory address to look up in the mapping table in the memory 110,
respectively, and obtains a corresponding look-up result. Then, the
converting module 120 sets the corresponding look-up result to be
the corresponding second image grayscale values Vc. In an example,
each of the first image grayscale values V is a 24-bits long binary
value. The converting module 120 utilizes each of the 24-bits long
binary values as a memory address to look up in the mapping table,
and obtains look-up results with 24-bits binary values,
respectively. The converting module 120 sets the corresponding
look-up results as the corresponding second image grayscale values
Vc, respectively.
[0030] Compared with the abovementioned embodiment, where the
converting module 120 utilizes all of the bits corresponding to
each of the first image grayscale values V as the memory address to
look up in the mapping table, in another embodiment of the present
disclosure, the converting module 120 utilizes only part of bits
corresponding to each of the first image grayscale values V as the
memory address to look up in the mapping table. In another
embodiment of the present disclosure, each of the first image
grayscale values V includes n first pixel grayscale values with
different colors. Each of the n first pixel grayscale values is
represented by m bits. The converting module 120 utilizes
n.times.(m-i) bits corresponding to each of the first image
grayscale values V as the memory address to look up in the mapping
table, in which n>1 and m>i.ltoreq.1. The abovementioned
operations will be explained in more detail in the following
paragraph.
[0031] Reference is made simultaneously to FIG. 2. FIG. 2 is a
schematic diagram illustrating that the converting module 120
converts one of the first image grayscale values V to a
corresponding one of the second image grayscale values Vc. For
simplicity of explanation, FIG. 2 is illustrated based on the
embodiment shown in FIG. 1, but is not limited thereto.
[0032] It is noted that, in the present embodiment, n is 3.
However, in practical applications, n is not limited to 3. The
value of n can be adjusted by persons skilled in the art according
to practical needs.
[0033] As shown in FIG. 2, each of the first image grayscale values
V includes first pixel grayscale values with three different colors
(e.g., red, green and blue). Each of the first pixel grayscale
values is represented by m bits. To be more precise, the
abovementioned three first pixel grayscale values are corresponding
to R[1]-R[m], G[1]-G[m] and B[1]-B[m], respectively. Each of the
second image grayscale values Vc includes three corresponding
second pixel grayscale values, and each of the three second pixel
grayscale values is represented by m bits as well. In other words,
the three second pixel grayscale values are corresponding to
Rc[1]-Rc[m], Gc[1]-Gc[m] and Bc[1]-Bc[m], respectively.
[0034] In an example, when m is 8, and a red first pixel grayscale
value is 146, the red first pixel grayscale value is corresponding
to 10010010. When a green first pixel grayscale value is 61, the
green first pixel grayscale value is corresponding to 00111101.
When a blue first pixel grayscale value is 171, the blue first
pixel grayscale value is corresponding to 10101011.
[0035] The converting module 120 utilizes 3.times.(m-i) bits
corresponding to each of the first image grayscale values V as the
memory address to look up in the mapping table, and converts the
3.times.(m-i) bits of each of the first image grayscale values V
into a corresponding 3.times.(m-i) bits of each of the second image
grayscale values Vc.
[0036] In the present embodiment, the converting module 120
utilizes the highest (m-i) bits of each of the three first pixel
grayscale values as the memory address to look up in the mapping
table, and sets the look-up result Vc' (with a length of
3.times.(m-i) bits) to be the highest (m-i) bits of a corresponding
one of the three second pixel grayscale values.
[0037] Further, the converting module 120 utilizes the
3.times.(m-i) bits V' consisting of R[1]-R[m-i] of R[1]-R[m],
G[1]-G[m-i] of G[1]-G[m] and B[1]-B[m-i] of B[1]-B[m] as the memory
address to look up in the mapping table, and obtains the look-up
result Vc'.
[0038] The converting module 120 then sets Rc[1]-Rc[m-i],
Gc[1]-Gc[m-i] and Bc[1]-Bc[m-i] of the look-up result Vc' to be the
highest (m-i) bits of a corresponding one of the three second pixel
grayscale values, respectively.
[0039] According to one embodiment of the present disclosure, the
converting module 120 is further used for integrating the n.times.i
un-converted bits and the corresponding n.times.(m-i) converted
bits of each of the first image grayscale values V, so as to
generate a corresponding second image grayscale values. As shown in
FIG. 2, the converting module 120 integrates the 3.times.i
un-converted bits R[m-i+1]-R[m], G[m-i+1]-G[m] and B[m-i+1]-B[m],
and the 3.times.(m-i) converted bits Rc[1]-Rc[m-i], Gc[1]-Gc[m-i]
and Bc[1]-Bc[m-i] of the first image grayscale value V to generate
the corresponding second image grayscale value Vc.
[0040] According to another embodiment of the present disclosure,
the converting module 120 optionally includes a delay unit (not
shown). In one embodiment, the delay unit is a circuit. In another
embodiment, the delay unit is realized by a software module. The
delay unit is configured for delaying the n.times.i un-converted
bits of each of the first image grayscale values V for a period of
time to compensate the time needed by the converting module 120 to
look up the n.times.(m-i) bits corresponding to each of the first
image grayscale values V in the mapping table stored in the memory
110. Consequently, the converting module 120 can integrate the
n.times.i un-converted bits and the corresponding n.times.(m-i)
converted bits of each of the first image grayscale values V to
generate a corresponding second image grayscale value Vc when the
look-up operation is finished.
[0041] According to another embodiment of the present disclosure,
the lowest i bits of each of the three second pixel grayscale
values are the same as the lowest i bits of each corresponding
pixel grayscale value of the three first pixel grayscale values. As
shown in FIG. 2, in the corresponding second image grayscale value
Vc, the lowest i bits Rc[m-i+1]-Rc[m] of the second pixel grayscale
value Rc[1]-Rc[m] are the lowest i bits R[m-i+1]-R[m] of the first
pixel grayscale value R[1]-R[m]. The lowest i bits Gc[m-i+1]-Gc[m]
of the second pixel grayscale value Gc[1]-Gc[m] are the lowest i
bits G[m-i+1]-G[m] of the first pixel grayscale value G[1]-G[m].
The lowest i bits Bc[m-i+1]-Bc[m] of the second pixel grayscale
value Bc[1]-Bc[m] are the lowest i bits B[m-i+1]-B[m] of the first
pixel grayscale value B[1]-B[m].
[0042] In other words, the converting module 120 sets
Rc[1]-Rc[m-i], Gc[1]-Gc[m-i] and Bc[1]-Bc[m-i] of the look-up
result Vc' to be the highest (m-i) bits of a corresponding one of
the three second pixel grayscale values, respectively, and the
lowest i bits of each of the three first pixel grayscale values to
be the lowest i bits of a corresponding one of the three second
pixel grayscale values, respectively. An example will be given in
the following paragraph to further explain the abovementioned
operations.
[0043] Additional reference is made to FIG. 3. FIG. 3 is a
schematic diagram illustrating that the converting module 120
converts one of the first image grayscale values V to a
corresponding one of the second image grayscale values Vc. For
simplicity of explanation, FIG. 3 is illustrated based on the
embodiment shown in FIG. 1, but is not limited thereto.
[0044] In the present embodiment, n=3, m=8 and i=1. However, in
practical applications, n, m and i are not limited to the
abovementioned values, and persons skilled in the art can adjust
the abovementioned values according to practical needs.
[0045] As shown in FIG. 3, each of the first image grayscale values
V includes three first pixel grayscale values, i.e., R[1]-R[8],
G[1]-G[8] and B[1]-B[8]. Each of the second image grayscale values
Vc includes three corresponding second pixel grayscale values,
i.e., Rc[1]-Rc[8], Gc[1]-Gc[8] and Bc[1]-Bc[8].
[0046] The converting module 120 utilizes the 21 bits V' consisting
of R[1]-R[7], G[1]-G[7] and B[1]-B[7] as the memory address to look
up in the mapping table, and obtains the look-up result Vc'
[0047] The converting module 120 then sets Rc[1]-Rc[7], Gc[1]-Gc[7]
and Bc[1]-Bc[7] of the look-up result Vc' to be the 1st-7th,
9th-15th and 17th-23rd bits of the corresponding second image
grayscale value Vc, respectively. Moreover, the converting module
120 sets R[8], G[8] and B[9] to be the 8th, 16th and 24th bits of
the corresponding second image grayscale value Vc (i.e, Rc[8],
Gc[8] and Bc[8]), respectively.
[0048] In the abovementioned embodiments, the converting module 120
utilizes part of bits corresponding to each of the first image
grayscale values V as the memory address to look up in the mapping
table. Consequently, the memory space in the memory 110 required to
save the mapping table can be greatly reduced.
[0049] To be more specific, when the converting module 120 utilizes
all of the bits corresponding to each of the first image grayscale
values V as the memory address to look up in the mapping table, the
memory space required in the memory 110 to save the mapping table
is n.times.m.times.(2 (n.times.m)) bits. However, when the
converting module 120 utilizes n.times.(m-i) bits corresponding to
each of the first image grayscale values V as the memory address V'
to look up in the mapping table, and generates the corresponding
second image grayscale values Vc according to the look-up result
Vc', only n.times.(m-i).times.(2 (n.times.(m-i))) bits in the
memory 110 are required to save the mapping table.
[0050] As an example, when n=3, m=8 and i=1, when the converting
module 120 utilizes all of the bits corresponding to each of the
first image grayscale values V as the memory address to look up in
the mapping table, the memory space in the memory 110 required to
save the mapping table is 3.times.8.times.(2 24)=384 M bits.
However, when the converting module 120 utilizes n.times.(m-i) bits
corresponding to each of the first image grayscale values V as the
memory address V' to look up in the mapping table, only
3.times.7.times.(2 21)=42 M bits in the memory 110 are required to
save the mapping table. Consequently, 384 M-42 M=342 M bits of
memory space are saved.
[0051] Furthermore, the grayscale values of neighboring color data
are usually successive values. Therefore, by utilizing the
n.times.(m-i) bits consisting of the highest (m-i) bits of each of
the n first pixel grayscale values as the memory address to look up
in the mapping table, and setting the lowest bit of each of the n
second pixel grayscale values to be the same as the lowest bit of a
corresponding one of the n first pixel grayscale values, the
successive property can be effectively kept for the grayscale
values in the converted image signal. In the previous example, a
near 24 bits color mapping operation is realized by utilizing a
mapping table occupying 42 M bits of memory space.
[0052] According to another embodiment of the present disclosure,
the converting module 120 is further configured for determining
whether a first image grayscale value to be converted is within an
image grayscale value range, in which the first image grayscale
value to be converted is one of the first image grayscale values.
If the first image grayscale value to be converted is not within
the image grayscale value range, the converting module 120 sets a
corresponding second image grayscale value of the second image
grayscale values Vc to be the same as the first image grayscale
value to be converted.
[0053] In one embodiment of the present disclosure, the converting
module 120 determines whether the first image grayscale value to be
converted is within the image grayscale value range according to
whether the n first pixel grayscale values of the first image
grayscale value to be converted are within corresponding pixel
grayscale value ranges.
[0054] In one embodiment, n=3, m=8 and i=1, and each of the first
image grayscale value V is a 24 bits value as shown in FIG. 3.
Furthermore, in that embodiment, the corresponding pixel grayscale
value ranges are 0.ltoreq.R.ltoreq.127, 0.ltoreq.G.ltoreq.127 and
128.ltoreq.B.ltoreq.255.
[0055] As an example, a first image grayscale value to be converted
has R[1]-R[8] being 10010010, G[1]-G[8] being 00111101 and
B[1]-B[8] being 10101011 (i.e., R=146, G=61 and B=171). Since the
grayscale value of R is not within the corresponding pixel
grayscale value range, 0.ltoreq.R.ltoreq.127, the converting module
120 determines that the first image grayscale value to be converted
is not within the image grayscale value range. Hence, the
converting module 120 sets a corresponding second image grayscale
value to be the same as the first image grayscale value to be
converted.
[0056] In another example, a first image grayscale value to be
converted has R[1]-R[8] being 01110010, G[1]-G[8] being 01010101
and B[1]-B[8] being 11001010 (i.e., R=114, G=85 and B=202). Since
the grayscale values of R, G and B are within the corresponding
pixel grayscale value ranges, the converting module 120 determines
that the first image grayscale value to be converted is within the
image grayscale value range. Hence, the converting module 120
performs the table look-up operation as shown in FIG. 3 on the
first image grayscale value to be converted, so as to generate a
corresponding second image grayscale value.
[0057] It is noted that the corresponding pixel grayscale value
ranges are not limited to the abovementioned 0.ltoreq.R.ltoreq.127,
0.ltoreq.G.ltoreq.127 and 128.ltoreq.B.ltoreq.255. Persons skilled
in the art can adjust the abovementioned ranges according to
practical needs. In another embodiment, the corresponding pixel
grayscale value ranges are 64.ltoreq.R.ltoreq.192,
64.ltoreq.G.ltoreq.192 and 64.ltoreq.B.ltoreq.192.
[0058] In the previous embodiment, by checking whether a first
image grayscale value to be converted is within an image grayscale
value range, the converting module 120 determines whether the table
look-up operation on the first image grayscale value is performed.
Consequently, the memory space in the memory 110 required to save
the mapping table can be effectively reduced. Moreover, by setting
the abovementioned image grayscale value range, color mappings for
some specific color ranges can be realized.
[0059] Reference is now made to FIG. 4. FIG. 4 is a flow chart of a
real-time color mapping method in accordance with one embodiment of
the present disclosure. The real-time color mapping method may be
implemented by the real-time color mapping system 100 shown in FIG.
1, but is not limited in this regard. For convenience and clarity,
it is assumed that the real-time color mapping method is
implemented by the real-time color mapping system 100 shown in FIG.
1.
[0060] In step 402, the converting module 120 reads a mapping table
stored in a memory 110.
[0061] In step 404, the converting module 120 utilizes at least
part of bits V' corresponding to each of a plurality of first image
grayscale values V corresponding to a first image signal 203 as a
memory address to look up in the mapping table, so as to convert
the first image grayscale values V into a plurality of second image
grayscale values Vc corresponding to a second image signal 223.
[0062] According to one embodiment of the present disclosure, the
operation of utilizing the at least part of bits corresponding to
each of the first image grayscale values V as the memory address to
look up in the mapping table is to utilize all of the bits
corresponding to each of the first image grayscale values V as the
memory address to look up in the mapping table.
[0063] According to another embodiment of the present disclosure,
each of the first image grayscale values V includes n first pixel
grayscale values with different colors. Each of the n first pixel
grayscale values is represented by m bits. The operation of
utilizing the at least part of bits corresponding to each of the
first image grayscale values V as the memory address to look up in
the mapping table is to utilize n.times.(m-i) bits corresponding to
each of the first image grayscale values V as the memory address to
look up in the mapping table, in which n>1 and
m>i.gtoreq.1.
[0064] According to still another embodiment of the present
disclosure, the (m-i) bits corresponding to each of the n first
pixel grayscale values are the highest (m-i) bits (e.g., as the
first image grayscale values V and the bits V' illustrated in FIG.
2).
[0065] According to yet another embodiment, each of the
abovementioned second image grayscale values Vc includes n
corresponding second pixel grayscale values. Each of the n second
pixel grayscale values is represented by m bits. Moreover, the
operation of utilizing the n.times.(m-i) bits corresponding to each
of the first image grayscale values V as the memory address to look
up in the mapping table to convert the first image grayscale values
V into the second image grayscale values Vc further includes:
converting the n.times.(m-i) bits of each of the first image
grayscale values V into corresponding n.times.(m-i) bits of each of
the second image grayscale values Vc according to a look-up result
(e.g., as the bits Vc' and the second image grayscale values Vc
shown in FIG. 2).
[0066] According to still yet another embodiment, the (m-i) bits
corresponding to each of the n first pixel grayscale values are the
highest (m-i) bits (e.g., as the second image grayscale values Vc
illustrated in FIG. 2).
[0067] According to another embodiment, the operation of utilizing
the n.times.(m-i) bits corresponding to each of the first image
grayscale values V as the memory address to look up in the mapping
table to convert the first image grayscale values V into the second
image grayscale values Vc further includes: integrating the
n.times.i un-converted bits and the corresponding n.times.(m-i)
converted bits of each of the first image grayscale values V to
generate the corresponding second image grayscale value.
[0068] According to still another embodiment, the lowest i bits of
each of the abovementioned n second pixel grayscale values are the
same as the lowest i bits of each corresponding pixel grayscale
value of the abovementioned n first pixel grayscale values.
[0069] According to still yet another embodiment, the operation of
utilizing the at least part of bits corresponding to each of the
first image grayscale values V as the memory address to look up in
the mapping table to convert the first image grayscale values V
into the second image grayscale values Vc further includes:
determining whether a first image grayscale value to be converted
is within an image grayscale value range, in which the first image
grayscale value to be converted is one of the first image grayscale
values V; and if the first image grayscale value to be converted is
not within the image grayscale value range, setting a corresponding
second image grayscale value of the second image grayscale values
Vc to be the same as the first image grayscale value to be
converted.
[0070] According to another embodiment, each of the first image
grayscale values includes n first pixel grayscale values with
different colors. Moreover, whether the first image grayscale value
to be converted (from one of the first image grayscale values V) is
within the image grayscale value range is determined according to
whether the n first pixel grayscale values of the first image
grayscale value to be converted are within corresponding pixel
grayscale value ranges.
[0071] Reference is further made to FIG. 5. FIG. 5 is a flow chart
of a real-time color mapping method in accordance with one
embodiment of the present disclosure. Compared with the real-time
color mapping method shown in FIG. 4, the real-time color mapping
method shown in FIG. 5 further includes steps 502 and 504. The
real-time color mapping method may be implemented by the real-time
color mapping system 100 shown in FIG. 1, but is not limited in
this regard. For convenience and clarity, it is assumed that the
real-time color mapping method is implemented by the real-time
color mapping system 100 shown in FIG. 1.
[0072] In step 502, the first storage unit 210 is utilized to store
first image data of the first image signal 203. The first image
data include a plurality of first image grayscale values V.
[0073] In step 504, the second storage unit 220 is utilized to
store second image data of the second image signal 223. The second
image data include the second image grayscale values Vc.
[0074] The above illustrations include exemplary operations, but
the operations are not necessarily performed in the order shown.
Operations may be added, replaced, changed order, and/or eliminated
as appropriate, in accordance with the spirit and scope of various
embodiments of the present disclosure.
[0075] In the present disclosure, by utilizing the grayscale values
of image signals as the memory address to look up in the mapping
table, a fast and real-time color mapping between image signals can
be realized. Compared with the conventional methods (e.g., color
mappings based on gamma curve adjustments), the color mapping
disclosed in the present disclosure is more precise with more
freedom for conversions. The present disclosure also discloses
utilizing only part of bits corresponding to image grayscale values
as the memory address to look up in the mapping table.
Consequently, the memory space in the memory required to save the
mapping table can be greatly reduced. Also, the continuity of the
grayscale values can be effectively kept in the converted image
signals. In one embodiment of the present disclosure, a near 24
bits color mapping can be performed by utilizing a mapping table
occupying only 42 M bits of memory space. Therefore, the memory
required for color mappings can be reduced, and the speed of color
mappings can be improved without affecting the effects of color
displaying.
[0076] Moreover, the present disclosure also discloses determining
whether the table look-up operation on a first image grayscale
value is performed by checking whether the first image grayscale
value to be converted is within an image grayscale value range.
Consequently, the memory space in the memory required to save the
mapping table can again be effectively reduced. Moreover, by
setting the abovementioned image grayscale value range, color
mappings for some specific color ranges can be realized.
[0077] Although the present disclosure has been described in
considerable detail with reference to certain embodiments thereof,
other embodiments are possible. Therefore, the spirit and scope of
the appended claims should not be limited to the description of the
embodiments contained herein.
[0078] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present disclosure without departing from the scope or spirit of
the disclosure. In view of the foregoing, it is intended that the
present disclosure cover modifications and variations of this
disclosure provided they fall within the scope of the following
claims.
* * * * *