U.S. patent number RE43,647 [Application Number 12/841,862] was granted by the patent office on 2012-09-11 for region-based information compaction as for digital images.
This patent grant is currently assigned to Akikaze Technologies, LLC. Invention is credited to Glenn Arthur Reitmeier, Michael Tinker.
United States Patent |
RE43,647 |
Reitmeier , et al. |
September 11, 2012 |
**Please see images for:
( Certificate of Correction ) ** |
Region-based information compaction as for digital images
Abstract
A method and apparatus for preserving the dynamic range of a
relatively high dynamic range information stream, illustratively a
high resolution video signal, subjected to a relatively low dynamic
range encoding and/or transport process(es). A relatively high
dynamic range information stream is subjected to a segmentation and
remapping process whereby each segment is remapped to the
relatively low dynamic range appropriate to the encoding and/or
transport process(es) utilized. An auxiliary information stream
includes segment and associated remapping information such that the
initial, relatively high dynamic range information stream may be
recovered in a post-encoding (i.e. decoding) or post-transport
(i.e., receiving) process.
Inventors: |
Reitmeier; Glenn Arthur
(Morrisville, PA), Tinker; Michael (Morrisville, PA) |
Assignee: |
Akikaze Technologies, LLC
(Wilmington, DE)
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Family
ID: |
23125789 |
Appl.
No.: |
12/841,862 |
Filed: |
July 22, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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09292693 |
Apr 15, 1999 |
6560285 |
|
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09050304 |
Mar 30, 1998 |
6118820 |
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Reissue of: |
10429985 |
May 6, 2003 |
7403565 |
Jul 22, 2008 |
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Current U.S.
Class: |
375/240.16;
375/E7.205; 375/240.01; 375/E7.272; 375/240.12; 375/E7.081 |
Current CPC
Class: |
H04N
19/46 (20141101); H04N 21/440245 (20130101); H04N
19/85 (20141101); H04N 21/23614 (20130101); H04N
21/4348 (20130101); H04N 19/98 (20141101); H04N
19/61 (20141101); H04N 21/234345 (20130101) |
Current International
Class: |
H04N
7/12 (20060101) |
Field of
Search: |
;375/240,240.01,240.12,240.16,240.24,240.27,E7.081,E7.205,E7.272
;382/233 ;386/227 |
References Cited
[Referenced By]
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Oct 2000 |
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WO |
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Other References
US. Appl. No. 11/635,063, filed Dec. 7, 2006, Tinker et al. cited
by other .
Chen, et al.: "Coding of Subregions Content-Based Scalable Video":
IEEE Transactions on Circuits and Systems for Video Technology,
7(1), Feb. 1, 1997, pp. 256-260. cited by other .
PCT International Search Report dated Apr. 16, 1999 in
corresponding International Application No. PCT/US99/00351. cited
by other .
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by other .
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by other.
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Primary Examiner: Wong; Allen
Attorney, Agent or Firm: Woodcock Washburn LLP
Parent Case Text
This application is a .Iadd.reissue application of U.S. patent
application Ser. No. 10,429,985, filed May 6, 2003, now patented as
U.S. Pat. No. 7,403,565, which is a .Iaddend.continuation of U.S.
patent application Ser. No. 09/292,693, filed Apr. 15, 1999 now
U.S. Pat. No. 6,560,285, which is a continuation in part of U.S.
patent application Ser. No. 09/050,304, filed on Mar. 30, 1998 now
U.S. Pat. No. 6,118,820 for Region-Based Information Compaction as
for Digital Images, which are herein incorporated by reference in
their entirety.
Claims
What is claimed is:
1. A method for encoding an information frame, comprising .[.the
steps of.].: dividing said information frame into a plurality of
information regions, at least one of said information regions
comprising at least one information parameter .[.having.].
associated with .[.it.]. a plurality of intra-region values bounded
by upper and lower value limits defining a dynamic range of said
information parameter; determining, for each of said at least one
of said information regions, a respective maximal value and a
minimal value of said at least one information parameter;
remapping, for each of said at least one of said information
regions and according to a single manipulation of the respective
determined maximal and minimal values, at least one respective of
said plurality of intra-region values of said at least one
information parameter; and encoding each of said information
regions; wherein said information frame comprises an image frame
and said at least one information parameter comprises at least one
of a luminance parameter and a chrominance parameter; wherein said
steps of encoding and determining produce, respectively, an encoded
image stream and an associated dynamic range enhancement stream;
and wherein said step of remapping is performed in accordance with
the following linear equation: TP=[OP*(TR/OR)+0.5] where: TP=Target
Pixel; OP=Original Pixel; TR=Target Range; and OR=Original
Range.
2. A method for encoding an information frame, comprising .[.the
steps of.].: dividing said information frame into a plurality of
information regions, at least one of said information regions
comprising at least one information parameter .[.having.].
associated with .[.it.]. a plurality of intra-region values bounded
by upper and lower value limits defining a dynamic range of said
information parameter; determining, for each of said at least one
of said information regions, a respective maximal value and a
minimal value of said at least one information parameter;
remapping, for each of said at least one of said information
regions and according to a single manipulation of the respective
determined maximal and minimal values, at least one respective of
said plurality of intra-region values of said at least one
information parameter; and encoding each of said information
regions; wherein said plurality of information frames comprise
image frames, said at least one information parameter comprises at
least one of a luminance parameter and a chrominance parameter;
wherein said steps of encoding and determining produce,
respectively, an encoded image stream and an associated dynamic
range enhancement stream; wherein said steps of dividing,
determining, remapping and encoding are repeated for each of a
plurality of information frames; and wherein said step of remapping
is performed in accordance with the following linear equation:
TP=[OP*(TR/OR)+0.5] where: TP=Target Pixel; OP=Original Pixel;
TR=Target Range; and OR=Original Range.
3. A method for decoding an encoded information frame represented
by a plurality of encoded information regions within an encoded
information stream, where at least one of said plurality of encoded
information regions comprises at least one information parameter
having associated with it a plurality of remapped intra-region
values, said method comprising .[.the steps of.].: decoding each of
said plurality of encoded information regions to form a
corresponding plurality of decoded information regions, said
decoded information regions representing a decoded information
frame; extracting, from a dynamic range enhancement stream
associated with said encoded information stream, respective maximal
and minimal values for each of said at least one information
parameter .[.having.]. associated with .[.it.]. a plurality of
remapped intra-region values; inverse remapping, according to a
single manipulation of said respective maximal and minimal values,
each of said at least one information parameter of said at least
one information regions having associated with it a respective
plurality of remapped intra-region values; and demultiplexing a
transport stream to recover said encoded information stream and
said dynamic range enhancement stream; wherein said encoded
information stream and said dynamic range enhancement stream
associated with said encoded information stream comprises
respective portions of said transport stream; wherein said step of
demultiplexing comprises retrieving, from a private data section of
said transport stream, said dynamic range enhancement stream;
wherein said decoded information frame comprises an image frame and
said at least one information parameter comprises at least one of a
luminance parameter and a chrominance parameter; and wherein said
step of inverse remapping is performed in accordance with the
following linear equation: TP=[OP*(TR/OR)+0.5] where: TP=Target
Pixel; OP=Original Pixel; TR=Target Range; and OR=Original
Range.
4. A method for decoding an encoded information frame represented
by a plurality of encoded information regions within an encoded
information stream, where at least one of said plurality of encoded
information regions comprises at least one information parameter
having associated with it a plurality of remapped intra-region
values, said method comprising the steps of: decoding each of said
plurality of encoded information regions to form a corresponding
plurality of decoded information regions, said decoded information
regions representing a decoded information frame; extracting, from
a dynamic range enhancement stream associated with said encoded
information stream, respective maximal and minimal values for each
of said at least one information parameter .[.having.]. associated
with .[.it.]. a plurality of remapped intra-region values; and
inverse remapping, according to a single manipulation of said
respective maximal and minimal values, each of said at least one
information parameter of said at least one information regions
having associated with it a respective plurality of remapped
intra-region values; wherein said steps of decoding, extracting and
inverse remapping are repeated for each of a plurality of
information frames within said encoded information stream and said
dynamic range enhancement stream associated with said encoded
information stream; wherein said decoding step comprises
compression decoding said encoded information frame of said
information stream; and wherein said step of inverse remapping is
performed in accordance with the following linear equation:
TP=[OP*(TR/OR)+0.5] where: TP=Target Pixel; OP=Original Pixel;
TR=Target Range; and OR=Original Range.
5. An apparatus for decoding an encoded information frame
represented by a plurality of encoded information regions within an
encoded information stream, where at least one of said plurality of
encoded information regions comprises at least one information
parameter having associated with it a plurality of remapped
intra-region values, said apparatus comprising: a decoder, for
decoding each of said plurality of encoded information regions to
form a corresponding plurality of decoded information regions, said
decoded information regions representing a decoded information
frame; and an inverse map and scale unit, for extracting, from a
dynamic range enhancement stream associated with said encoded
information stream, respective maximal and minimal values for each
of said at least one information parameter .[.having.]. associated
with .[.it.]. a plurality of remapped intra-region values, and for
inverse remapping, according to a single manipulation of said
respective maximal and minimal values, each of said at least one
information parameter of said at least one of said plurality of
encoded information regions having associated with it said
plurality of remapped intra-region values; wherein said decoded
information frame comprises an image frame and said at least one
information parameter comprises at least one of a luminance
parameter and a chrominance parameter; and wherein said inverse map
and scale unit extracts said respective maximal and minimal values
in accordance with the following linear equation:
TP=[OP*(TR/OR)+0.5] where: TP=Target Pixel; OP=Original Pixel;
TR=Target Range; and OR=Original Range.
6. An apparatus for decoding an encoded information frame
represented by a plurality of encoded information regions within an
encoded information stream, where at least one of said plurality of
encoded information regions comprises at least one information
parameter having associated with it a plurality of remapped
intra-region values, said apparatus comprising: a decoder, for
decoding each of said plurality of encoded information regions to
form a corresponding plurality of decoded information regions, said
decoded information regions representing a decoded information
frame; and an inverse map and scale unit, for extracting, from a
dynamic range enhancement stream associated with said encoded
information stream, respective maximal and minimal values for each
of said at least one information parameter .[.having.]. associated
with .[.it.]. a plurality of remapped intra-region values, and for
inverse remapping, according to a single manipulation of said
respective maximal and minimal values, each of said at least one
information parameter of said at least one of said plurality of
encoded information regions having associated with it said
plurality of remapped intra-region values; wherein said encoded
information stream and said dynamic range enhancement stream
associated with said encoded information stream represent a
plurality of encoded information frames; wherein said apparatus
processes each of said plurality of encoded information frames to
produce a corresponding plurality of decoded information frames;
wherein said plurality of decoded information frames comprise image
frames and said at least one information parameter comprises at
least one of a luminance parameter and a chrominance parameter; and
wherein said inverse map and scale unit extracts said respective
maximal and minimal values in accordance with the following linear
equation: TP=[OP*(TR/OR)+0.5] where: TP=Target Pixel; OP=Original
Pixel; TR=Target Range; and OR=Original Range.
7. A method for remapping a value of a parameter of an information
element from a first representation system to a second
representation system, comprising: dividing a collection of
information elements into regions; determining a region of the
regions, wherein the information element is within the region;
determining, among the information elements within the region, a
maximum value of the parameter; determining, among the information
elements within the region, a minimum value of the parameter;
subtracting the minimum value from the value of the parameter of
the information element to yield a first difference; subtracting
the minimum value from the maximum value to yield a second
difference; dividing a dynamic range of values of the parameter
associated with the second representation system by the second
difference to yield a quotient; multiplying the quotient by the
first difference to yield a product; adding the product to one half
to yield a sum; and rounding the sum to a nearest integer that is
less than or equal to the sum to yield a remapped value of the
parameter of the information element.
8. The method of claim 7, wherein the second difference is raised
to a power before the dividing the dynamic range of values of the
parameter associated with the second representation system by the
second difference, the first difference is raised to the power
before the multiplying the quotient by the first difference, a
function is determined before the adding the product to one half to
yield the sum, and the product is a variable of the function.
9. The method of claim 7, wherein the information element is a
pixel.
10. The method of claim 9, wherein the collection of information
elements is an image frame.
11. The method of claim 7, further comprising performing, for each
remaining information element within the region, the subtracting
the minimum value from the value of the parameter of the
information element, the subtracting the minimum value from the
maximum value, the dividing the dynamic range of values of the
parameter associated with the second representation system by the
second difference, the multiplying the quotient by the first
difference, the adding, and the rounding.
12. The method of claim 11, further comprising performing, for each
remaining region of the regions, the determining, among the
information elements within the region, the maximum value of the
parameter and the determining, among the information elements
within the region, the minimum value of the parameter to yield a
collection of maximum values and a collection of minimum
values.
13. The method of claim 12, further comprising performing, for each
information element within the each remaining region, the
subtracting the minimum value from the value of the parameter of
the information element, the subtracting the minimum value from the
maximum value, the dividing the dynamic range of values of the
parameter associated with the second representation system by the
second difference, the multiplying the quotient by the first
difference, the adding, and the rounding.
14. The method of claim 13, further comprising encoding the regions
to yield encoded regions.
15. The method of claim 14, further comprising transporting the
encoded regions, the collection of maximum values, and the
collection of minimum values.
16. The method of claim 13, further comprising decoding the
regions.
17. A method for remapping a value of a parameter of an information
element from a first representation system to a second
representation system, comprising: dividing a dynamic range of
values of the parameter associated with the second representation
system by a dynamic range of values of the parameter associated
with the first representation system to yield a quotient;
multiplying the quotient by the value of the parameter of the
information element to yield a product; adding the product to one
half to yield a sum; and rounding the sum to a nearest integer that
is less than or equal to the sum to yield a remapped value of the
parameter of the information element.
18. An apparatus for remapping a value of a parameter of an
information element from a first representation system to a second
representation system, comprising: a receiver configured to receive
a collection of information elements; and a processor configured to
divide the collection of information elements into regions, to
determine a region of the regions, wherein the information element
is within the region, to determine, among the information elements
within the region, a maximum value of the parameter, to determine,
among the information elements within the region, a minimum value
of the parameter, to subtract the minimum value from the value of
the parameter of the information element to yield a first
difference, to subtract the minimum value from the maximum value to
yield a second difference, to divide a dynamic range of values of
the parameter associated with the second representation system by
the second difference to yield a quotient, to multiply the quotient
by the first difference to yield a product, to add the product to
one half to yield a sum, and to round the sum to a nearest integer
that is less than or equal to the sum to yield a remapped value of
the parameter of the information element.
19. The apparatus of claim 18, wherein the processor is further
configured to raise the second difference to a power before
dividing the dynamic range of values of the parameter associated
with the second representation system by the second difference, to
raise the first difference to the power before multiplying the
quotient by the first difference, and to determine a function
before adding the product to one half to yield the sum, wherein the
product is a variable of the function.
20. The apparatus of claim 18, further comprising an encoder
configured to encode the regions to yield encoded regions.
21. The apparatus of claim 20, further comprising a transporter
configured to transport the encoded regions, a collection of
maximum values, and a collection of minimum values.
22. The apparatus of claim 18, further comprising a decoder
configured to decode the regions.
23. An apparatus for remapping a value of a parameter of an
information element from a first representation system to a second
representation system, comprising a processor configured to divide
a dynamic range of values of the parameter associated with the
second representation system by a dynamic range of values of the
parameter associated with the first representation system to yield
a quotient, to multiply the quotient by the value of the parameter
of the information element to yield a product, to add the product
to one half to yield a sum, and to round the sum to a nearest
integer that is less than or equal to the sum to yield a remapped
value of the parameter of the information element.
.Iadd.24. In a system for encoding an information stream, a method
comprising: dividing the information stream into a plurality of
information regions; identifying, for at least one of the plurality
of information regions, a maximal value and a minimal value of at
least one information element associated with the least one of the
plurality of information regions; mapping the at least one
information element according to the identified maximal and minimal
values associated with the respective information region, wherein
said mapping comprises determining a target information element as
a function of an original information element, a target range, and
said maximal and minimal values, wherein the difference between the
maximal and minimal values is used to map the original information
element to the target range to generate a mapped information
element; encoding the mapped information element to produce an
encoded information stream; and associating said identified maximal
and minimal values with the at least one of the plurality of
information regions to produce a map identification stream, wherein
said map identification stream includes information sufficient to
substantially recover said identified maximal and minimal values
associated with said mapped at least one information
element..Iaddend.
.Iadd.25. The method of claim 24, wherein said mapping further
comprises using a combination of linear and non-linear
functions..Iaddend.
.Iadd.26. The method of claim 24, wherein said mapping further
comprises using a polynomial segment..Iaddend.
.Iadd.27. The method of claim 24, wherein said mapping further
comprises using a tabulated function comprising an indexable array
of values..Iaddend.
.Iadd.28. A method for encoding an information stream, said method
comprising: receiving a plurality of information frames, each of
said plurality of information frames comprising a plurality of
information elements, each of said plurality of information
elements associated with at least one information element
parameter, each of the at least one information element parameters
having a value between a lower limit and an upper limit, said upper
and lower limits defining a dynamic range of said at least one
information element parameter; defining, for each of the plurality
of information frames, a plurality of information regions, each of
the plurality of information regions being associated with one or
more respective information elements; identifying, for each of the
plurality of information regions, a maximal value and a minimal
value of at least one information element parameter associated with
said plurality of information elements of said region; remapping,
for each of said plurality of information regions, the at least one
information element parameter of each of said plurality of
information elements of said region according to the identified
maximal and minimal value parameters associated with the respective
region, wherein the difference between the maximal and minimal
value parameters is used to remap the at least one of said
plurality of information element parameters to a target range;
encoding each remapped information region of said plurality of
information regions to produce an encoded information stream; and
associating said identified maximal and minimal values with each
remapped information region of said plurality of information
regions to produce a map identification stream, wherein said map
identification stream includes information sufficient to
substantially recover said identified maximal and minimal value
parameters associated with said remapped at least one information
element parameter for each of said plurality of information
regions..Iaddend.
.Iadd.29. A method for encoding an information stream comprising a
plurality of information frames, said method comprising: receiving
the plurality of information frames; for at least one of the
plurality of information frames, dividing the at least one of the
plurality of information frames into regions according to at least
one criterion for rescaling a range of one or more parameters of
interest for at least one of the regions as compared to a range of
the one or more parameters of interest of the at least one of the
plurality of information frames; identifying a target range for
said one or more parameters of interest, the target range being
different from the range of the one or more parameters of interest;
and remapping, for at least one of said regions, the one or more
parameters of interest to the identified target range, the remapped
parameters being bounded by the target range..Iaddend.
.Iadd.30. The method of claim 29, further comprising encoding the
remapped regions to produced a compressed information
stream..Iaddend.
.Iadd.31. The method of claim 30, further comprising multiplexing
the encoded remapped regions with information for recovering the
regions..Iaddend.
Description
The invention relates to information processing systems in general,
and, more particularly, the invention relates to a method and
apparatus for preserving a relatively high dynamic range of an
information signal, such as a video information signal, processed
via a relatively low dynamic range information processing
system.
BACKGROUND OF THE DISCLOSURE
In some communications systems the data to be transmitted is
compressed so that the available bandwidth is used more
efficiently. For example, the Moving Pictures Experts Group (MPEG)
has promulgated several standards relating to the compression of
moving images and digital data delivery systems. The first, known
as MPEG-1 refers to ISO/IEC standards 11172 and is incorporated
herein by reference. The second, known as MPEG-2, refers to ISO/IEC
standards 13818 and is incorporated herein by reference. A
compressed digital video system is described in the Advanced
Television Systems Committee (ATSC) digital television standard
document A/53, and is incorporated herein by reference.
The above-referenced standards describe data processing and
manipulation techniques that are well suited to the compression and
delivery of video, audio and other information using fixed or
variable length digital communications systems. In particular, the
above-referenced standards, and other "MPEG-like" standards and
techniques, compress, illustratively, video information using
intra-frame coding techniques (such as run-length coding, Huffman
coding and the like) and inter-frame coding techniques (such as
forward and backward predictive coding, motion compensation and the
like). Specifically, in the case of video processing systems, MPEG
and MPEG-like video processing systems are characterized by
prediction-based compression encoding of video frames with or
without intra- and/or inter-frame motion compensation encoding.
Within respect to still images (or single image frames), several
well known standards are utilized to effect compression of image
information. For example, the Joint Photographic Experts Group
(JPEG) has promulgated a several standard relating to the
compression of still images, most notably the ISO/IEC 10918-1
(ITU-T T.81) standard, which is the first of a multi-part set of
standards for still image compression.
In the context of digital video processing and digital image
processing, information such as pixel intensity and pixel color
depth of a digital image is encoded as a binary integer between 0
and 2.sup.n-1. For example, film makers and television studios
typically utilize video information having 10-bit pixel intensity
and pixel color depth, which produces luminance and chrominance
values of between zero and 1023. While the 10-bit dynamic range of
the video information may be preserved on film and in the studio,
the above-referenced standards (and communication systems adapted
to those standards) typically utilize a dynamic range of only
8-bits. Thus, the quality of a film, video or other information
source provided to an ultimate information consumer is degraded by
dynamic range constraints of the information encoding methodologies
and communication networks used to provide such information to a
consumer.
Therefore, it is seen to be desirable to provide a method and
apparatus to preserve the dynamic range of film, video and other
forms of relatively high dynamic range information that are encoded
and transported according to relatively low dynamic range
techniques. Moreover, it is seen to be desirable to provide such
dynamic range preservation while utilizing economies of scale
inherent to these relatively low dynamic range techniques, such as
the above-referenced MPEG-like standards and techniques.
SUMMARY OF THE INVENTION
The invention comprises a method and apparatus for preserving the
dynamic range of a relatively high dynamic range information
stream, illustratively a high resolution video signal, subjected to
a relatively low dynamic range encoding and/or transport
process(es). The invention subjects the relatively high dynamic
range information stream to a segmentation and remapping process
whereby each segment is remapped to the relatively low dynamic
range appropriate to the encoding and/or transport process(es)
utilized. An auxiliary information stream includes segment and
associated remapping information such that the initial, relatively
high dynamic range information stream may be recovered in a
post-encoding (i.e. decoding) or post-transport (i.e., receiving)
process.
Specifically, a method for encoding an information frame according
to the invention comprises the steps of: dividing the information
frame into a plurality of information regions, at least one of the
information regions comprising at least one information parameter
having associated with it a plurality of intra-region values
bounded by upper and lower value limits defining a dynamic range of
the information parameter; determining, for each of the at least
one information region, a respective maximal value and a minimal
value of the at least one information parameter; remapping, for
each of the at least one information regions and according to the
respective determined maximal and minimal values, the respective
plurality of intra-region values of the at least one information
parameter; and encoding each information region.
BRIEF DESCRIPTION OF THE DRAWING
The teachings of the present invention can be readily understood by
considering the following detailed description in conjunction with
the accompanying figures, in which:
FIG. 1 depicts an information distribution system;
FIG. 2 is a flow diagram of a combined information stream encoding
method and decoding method;
FIG. 3A depicts an image that has been divided into a plurality of
regions using a pixel coordinate technique;
FIG. 3B depicts an image that has been divided into a plurality of
single macroblock regions defined by row and column;
FIG. 4A depicts a diagram illustrative of a non-linear encoding
function;
FIG. 4B depicts a diagram illustrative of a non-linear decoding
function associated with the encoding function of FIG. 4A; and
FIG. 5 depicts a high level function block diagram of an encoding
and decoding method and apparatus.
To facilitate understanding, identical reference numerals have been
used, where possible, to designate identical elements that are
common to the figures.
DETAILED DESCRIPTION
After considering the following description, those skilled in the
art will clearly realize that the teachings of the invention can be
readily utilized in any information processing system in which
relatively high dynamic range information is subjected to
relatively low dynamic range processing (e.g., encoding), and
subsequently reprocessed (e.g., decoded) to reproduce, ideally, the
original high dynamic range information or an approximation
thereto.
While the invention will primarily be discussed within the context
of multiple or moving image processed (e.g., MPEG-like video
processing), it will be appreciated by those skilled in the art
that the teachings of the present invention are readily applicable
to single or still image processing (e.g., JPEG-like image
processing). More generally, the teachings of the present invention
are applicable to any form of information comprising one or more
information parameters having associated with them a relatively
high dynamic range. The invention provides the capability to reduce
that dynamic range for, e.g., processing or transport, and
subsequently restore that dynamic range.
FIG. 1 depicts an information distribution system 100 that encodes,
illustratively, a 10-bit dynamic range information stream using a
pre-processing function to produce a range enhancement information
stream, and an 8-bit encoding process, illustratively an MPEG-like
encoding process, to produce an 8-bit encoded information stream.
The 8-bit encoded information stream and the range enhancement
information stream are transported to, e.g., a receiver. At the
receiver, the 8-bit encoded information stream is subjected to a
decoding process, illustratively an MPEG-like decoding process, to
produce an 8-bit decoded information stream. A post-processing
function utilizes the range enhancement information stream to
enhance the dynamic range of the 8-bit decoded information stream
such that the original 10-bit dynamic range is substantially
restored.
The system 100 of FIG. 1 comprises an information coding section
(10-30) suitable for use by, illustratively, an information
provider such as a television studio; an information distribution
section (35), illustratively a communication channel such as a
terrestrial broadcast channel; and an information decoding section
(40-60), suitable for use by, illustratively, an information
consumer having an appropriate decoding device.
The information coding section comprises a region map and scale
unit 10 that receives a relatively high dynamic range information
signal S1, illustratively a 10-bit dynamic range video signal, from
an information source such as a video source (not shown). The
region map and scale unit 10 divides each picture-representative,
frame-representative or field-representative portion of the 10-bit
video signal S1 into a plurality of, respectively, sub-picture
regions, sub-frame regions or sub-field regions. The operation of
region map and scale unit 10 will be described in more detail below
with respect to FIG. 2. Briefly, each of the plurality of regions
are processed to identify, illustratively, a maximum luminance
level (Y.sub.max) and a minimum luminance level (Y.sub.min)
utilized by pixels within the processed region. The luminance
information within each region is then scaled (i.e., remapped) from
the original 10-bit dynamic range (i.e., 0 to 1023) to an 8-bit
dynamic range having upper and lower limits corresponding to the
identified minimum luminance level (Y.sub.min) and maximum
luminance level (Y.sub.max) of the respective region to produce, at
an output, an 8-bit baseband video signal S3. The maximum and
minimum values associated with each region, and information
identifying the region, are coupled to an output as a map region ID
signal S4. In the case of, e.g., a region not requiring dynamic
range compaction, the map region ID signal may comprise an empty
set.
An encoder 15, illustratively an MPEG-like video encoder (or
JPEG-like image encoder), receives the remapped, 8-bit baseband
video (or image) signal S3 from the region map and scale unit 10.
The encoder 15 encodes the 8-bit baseband video signal to produce a
compressed video signal S5, illustratively an MPEG-like video
elementary stream.
An audio encoder 20, illustratively an MPEG-like audio encoder,
receives a baseband audio signal S2 from an audio source (not
shown). The baseband audio signal S2 is, typically, temporally
related to the baseband video signal S3. The audio encoder 20
encodes the baseband audio signal to produce a compressed audio
signal S16, illustratively an MPEG-like audio elementary stream. It
must be noted that audio encoder 20, and other audio functionality
to be described later, is not strictly necessary to the practice of
the invention.
A service multiplexer 25 wraps the map region ID signal S4, the
elementary stream S5 and the audio elementary stream S16 into
respective variable-length or fixed length packet structures known
as packetized elementary streams. The packetized elementary streams
(PES) are combined to form a multiplexed PES S6. The PES structure
provides, e.g., functionality for identification and
synchronization of decoding and presentation of the video, audio
and other information. A transport encoder 30 converts the PES
packets of multiplexed PES S6 into fixed-length transport packets
in a known manner to produce a transport stream S7.
It should be noted that the map region ID signal S4 may be
communicated to an end user (e.g., a decoder) via a plurality of
means within the context of, e.g., the various communications
standards. User private data tables and private data or message
descriptors incorporating the map region ID signal S4 may be placed
in designated locations throughout messages as described in the
MPEG and ATSC standards. The use of such data, and other MPEG,
ATSC, DVB and similar private, user or auxiliary data communication
formats is contemplated by the inventors. For example, since the
map region ID signal S4 includes information corresponding to
encoded region information within the elementary stream S5, in one
embodiment of the invention the map region ID signal is included as
private data within the multiplexed elementary stream S5.
The map region ID signal S4 may be communicated as an auxiliary
data stream, an MPEG-like data stream or a user private data or
message stream. Private data may comprise a data stream associated
with a particular packet identification (PID), private or user data
inserted into, e.g., a payload or header portion of another data
stream (e.g., a packetized elementary stream including the
elementary stream S5) or other portions of an information stream.
In the case of a transport stream, the map region ID signal S4 is
optionally incorporated into a transport stream private
section.
In one embodiment of the invention, the transport encoder includes,
in a private data section of the transport stream being formed, the
dynamic range enhancement stream. In another embodiment of the
invention, the transport encoder associated the encoded information
stream and the associated dynamic range enhancement stream with
respective packet identification (PID) values. In another
embodiment of the invention, the transport encoder incorporates,
into a packetized stream, the encoded information stream.
Additionally, the transport encoder includes, within a header
portion of the packetized stream incorporating the encoded
information stream, the associated dynamic range enhancement
stream.
The information distribution section comprises a communications
network 35, illustratively a terrestrial broadcast, fiber optic,
telecommunications or other public or private data communications
network. The communications network receives the transport stream
S7 produced by the information coding section; modulates or encodes
the transport stream S7 to conform to the requirements of the
communications network (e.g., converting the MPEG transport stream
S7 into an asynchronous transfer mode (ATM) format); transmits the
modulated or encoded transport stream to, e.g., a receiver; and
demodulates or decodes the modulated or encoded transport stream to
produce an output transport stream S8.
The information decoding section comprises a transport decoder 40
that converts the received transport stream S8 into a multiplexed
PES S9. The multiplexed PES S9 is demultiplexed by a service
demultiplexer 45 to produce a map region ID signal S14, a video
elementary stream S12 and an audio elementary stream S10
corresponding to, respectively, map region ID signal S4, elementary
stream S5 and audio elementary stream S16.
The video elementary stream S12 is decoded in a known manner by a
video decoder 55 to produce, an 8-bit baseband video signal S13
corresponding to the remapped 8-bit baseband video signal S3. The
audio elementary stream S10 is decoded in a known manner by an
audio decoder 50 to produce a baseband audio output signal S11,
corresponding to the baseband audio signal S2, which is coupled to
an audio processor (not shown) for further processing.
An inverse region map and scale unit 60 receives the 8-bit baseband
video signal S13 and the map region ID signal S14. The inverse
region map and scale unit 60 remaps the 8-bit baseband video signal
S13, on a region by region basis, to produce a 10-bit video signal
S15 corresponding to the original 10-bit dynamic range video signal
S1. The produced 10-bit video signal is coupled to a video
processor (not shown) for further processing. The operation of
inverse region map and scale unit 60 will be described in more
detail below with respect to FIG. 2. Briefly, the inverse region
map and scale unit 60 retrieves, from the map region ID signal S14,
the previously identified maximum luminance level (Y.sub.max) and
minimum luminance level (Y.sub.min) associated with each picture,
frame or field region, and any identifying information necessary to
associate the retrieved maximum and minimum values with a
particular region within the 8-bit baseband video signal S13. The
luminance information associated with each region is then scaled
(i.e., remapped) from the 8-bit dynamic range bounded by the
identified minimum luminance level (Y.sub.min) and maximum
luminance level (Y.sub.max) associated with the region to the
original 10-bit (i.e., 0-1023) dynamic range to produce the 10-bit
video signal S15. It will be appreciated by those skilled in the
art that other high dynamic range parameters associated with an
information signal (e.g., chrominance components, high dynamic
range audio information and the like) may also be advantageously
processed using the apparatus and method of the invention.
As previously noted, the map region ID signal S4 may be
communicated to an end user (e.g., a decoder) via a plurality of
means within the context of, e.g., the various communications
standards. Thus, in one embodiment of the invention, the map region
ID signal S4 is recovered from a private data section of said
transport stream. In another embodiment of the invention, the map
region ID signal is associated with a respective identification
(PID) value and recovered using that value. In another embodiment
of the invention, the encoded information stream is recovered from
a packetized stream associated with a predefined packet
identification (PID) value, while the map region ID signal is
retrieved form a header portion of the packetized stream associated
with the predefined packet identification (PID) value.
FIG. 2 is a flow diagram of a combined information stream encoding
method and decoding method. The method 200 is entered at step 210
when a relatively high dynamic range information stream comprising
a plurality of logical information frames is received by, e.g.,
region map and scale unit 10. The method 200 proceeds to step 215,
where each logical information frame of the received information
stream is divided into regions according to, illustratively, the
criteria depicted in box 205 which includes: fixed or variable
coordinate regions based on picture, frame, field, slice
macroblock, block and pixel location, related motion vector
information and the like. In the case of a video information
stream, any exemplary region comprises a macroblock region
size.
After dividing the logical information frames into regions (step
215) the method 200 proceeds to step 220, where the maximum and
minimum values of one or more parameters of interest are determined
for each region. In the case of a video information signal, a
parameter of interest may comprise a luminance parameter (Y), color
difference parameter (U, V), motion vector and the like.
The method 200 then proceeds to step 225, where the parameters of
interest in each pixel of each region are remapped to a parameter
value range bounded by respective maximum and minimum parameter
values. That is, if the parameter of interest of a pixel is a
luminance parameter, all the luminance parameters within a
particular region are remapped to a range determined by the maximum
luminance value and the minimum luminance value within the
particular region as previously determined in step 220.
The above described steps of regional division of logical frames,
maximum and minimum parameter(s) determination and remapping
comprise the steps necessary to generate an information stream and
an associated dynamic range enhancements stream. Specifically,
dynamic range degradation visited upon the information stream due
to a subsequent, relatively low dynamic range processing step
(e.g., step 230 below), may be largely corrected by a second,
subsequent processing step (e.g., steps 240-245 below). This
concept is critical to the understanding of the invention.
After remapping all of the parameters of interest in one or more
regions (step 225), the method 200 proceeds to step 230, where the
information within the region is encoded, to produce an encoded
information stream. In the case of a video information stream,
encoding may comprise one of the MPEG-like encoding standards
referenced above. The method 200 then proceeds to step 235, where
the encoded information stream, maximum and minimum data associated
with each region of the encoded information stream, and information
sufficient to associate each region with its respective maximum and
minimum parameter(s) information are transported to, e.g., a
receiver. The method 200 then proceeds to step 240, where the
encoded information stream is decoded to produce a decoded
information stream.
It is important to note that the dynamic range of the decoded
information stream, specifically the dynamic range of the
parameters of interest in the decoded information stream, will not
exceed the dynamic range of the encoding or processing methodology
employed in, e.g., steps 230-235. Thus, in the case of a ten bit
dynamic range luminance parameter of a video signal, and MPEG-like
encoding and decoding methodology which utilizes an eight bit
dynamic range will produce, at the decoder output, a video
information stream having only an eight bit dynamic range luminance
parameter.
After decoding the transported information stream (step 240), the
method 200 proceeds to step 245, where the eight bit dynamic range
decoded information stream is remapped on a region by region basis
using the respective maximum and minimum values associated with the
parameter or parameters of interest in each region. The resulting
relatively high dynamic range information stream is then utilized
at step 250.
The portions of the above-described method 200 related to regional
division and remapping will now be described in more detail below.
In addition, the relationship of the invention to information
streams in general, and video information streams in particular,
will also be described in more detail.
Information streams are typically segmented or framed according to
a logical constraint. Each logical segment or frame comprises a
plurality information elements, and each information element is
typically associated with one or more parameters. In particular,
video information streams are typically segmented in terms of a
picture, frame or field. The picture, frame or field comprises a
plurality of information elements known as picture elements
(pixels). Each pixel is associated with parameters such as
luminance information and chrominance information. In the case of
MPEG-like systems, pixels are grouped into blocks or macroblocks.
Pixels, blocks and macroblocks may also have associated with them
motion parameters and other parameters. Each of the parameters
associated with a pixel, block or macroblock is accurate to the
extent that the dynamic range of the information defining the
parameter is accurate. Moreover, preservation of the dynamic range
of some parameters, such as pixel luminance, is more critical than
preservation of the dynamic range of other parameters, such as
block motion. As such, degradation of some parameters due to
dynamic range constraints may be acceptable, while other parameters
should be preserved with as high a fidelity as possible.
In the case of luminance parameters, in an image comprising very
light areas (i.e., high intensity values) and very dark areas
(i.e., low intensity values), the dynamic range of the luminance
information representing the image may be fully utilized. That is,
the value of luminance parameters associated with pixels in the
image may be between (in a 10-bit dynamic range representation)
from zero (black) to 1023 (white). Thus, if the dynamic range of
the luminance information representing the image, illustratively a
10-bit studio image, exceeds the dynamic range of an information
processing operation used to process the image, illustratively an
8-bit MPEG encoding operation, quantization errors will necessarily
degrade the resulting processed image. However, by segmenting the
image into smaller regions, the probability that the full 10-bit
dynamic range of the luminance information is utilized in a region
decreases.
Regions may be selected according to any intra-frame selection
criteria. For example, in the case of a video information frame,
appropriate criteria include scan lines, regions defined by pixel
coordinates, blocks, macroblocks, slices and the like. In general,
the smaller the region selected, the greater the probability of
preserving the full dynamic range of the information element
parameter.
FIG. 3A depicts an image 300 that has been divided into a plurality
of regions 301-307 using a pixel coordinate technique. In an
embodiment of the invention utilizing region partitioning of an
image according to FIG. 3A, identifying indicia of region location
comprise pixel coordinates defining, e.g., corners or edges of the
regions.
FIG. 3B depicts an image 300 that has been divided into a plurality
of single macroblock regions defined by row (R.sub.1-R.sub.N) and
column (C.sub.1-C.sub.N). Since the regions defined in FIG. 3B are
much smaller then the regions defined in FIG. 3A, there is a
greater probability of preserving the dynamic range of the
parameters of interest forming the image. In an embodiment of the
invention utilizing region partitioning of an image according to
FIG. 3B, identifying indicia of region location comprise macroblock
address, as defined by row (i.e., slice) number and column number.
A simpler method of region identification comprises identifying
each region (i.e., macroblock) by a macroblock offset value
representing the number of macroblocks from the start of a picture
(i.e., the number of macroblocks from the top left, or first,
macroblock).
A simple linear remapping of, e.g., pixel luminance or chrominance
parameters from an original dynamic range to a target dynamic range
may be represented by equation 1, where TP=Target Pixel;
OP=Original Pixel; TR=Target Range; and OR=original Range. In the
case of remapping a 10-bit pixel (such as used in a studio) to an
8-bit pixel (such as used in MPEG-like processing systems),
equation 1 becomes equation 2. Similarly, in the case of remapping
the 8-bit pixel back to a 10-bit pixel equation 1 becomes equation
3. It should be noted that the quantities or results within the
floor function operators .left brkt-bot. .right brkt-bot. are
rounded down to the nearest integer value. TP=.left
brkt-bot.OP*(TR/OR)+0.5.right brkt-bot. (eq. 1) TP=.left
brkt-bot.OP*(256/1024)+0.5.right brkt-bot. (eq. 2) TP=.left
brkt-bot.OP*(1024/256)+0.5.right brkt-bot. (eq. 3)
Using equation 2, an OP of 525 will result in a TP of 131. Using
equation 3, an OP of 131 will result in a TP of 524. It can be seen
that the process of linear remapping from a 10-bit dynamic range to
an 8-bit dynamic range and back to the 10-bit dynamic range results
in a loss of information due to quantization errors.
The above equations 1-3 mathematically illustrate the quantization
error inherent in present remapping functions. By contrast, the
below described remapping equations 4 and 5 are suitable for use
in, respectively, the region map and scale unit 10 and inverse
region map and scale unit 60 of FIG. 1.
In one embodiment of the invention a linear remapping function,
such as the exemplary linear remapping function of equation 4, is
utilized, where TP=Target Pixel; OP=Original Pixel; TR=Target
Range; MAX=maximum parameter value and MIN=minimum parameter value.
In the case of a minimum of a 10-bit system having a regional
minimum of 400 and a regional maximum of 600, equation 4 becomes
equation 5. TP=.left brkt-bot.(OP-MIN)*(TR/(MAX-MIN))+0.5.right
brkt-bot. (eq. 4) TP=.left
brkt-bot.(OP-400)*(TR/(600-400))+0.5.right brkt-bot. (eq. 5)
Within the context of the invention, a function such as equation 4
will be able to preserve the relatively high dynamic range of the
original pixel parameter as long as the difference between the
maximum and minimum parameter values does not exceed a range
defined by the ratio of the original dynamic range and the target
dynamic range. That is, in the case of a 10-bit original dynamic
range and an 8-bit target dynamic range where the ratio is 1023:255
(i.e., 4:1), the difference between the maximum and minimum values
must not be greater than one fourth of the original dynamic range.
Thus, a threshold level of dynamic range for each region is
established that determines if the full, original dynamic range of
the parameter will be preserved by the invention. Since, in
equation 5, the difference between the maximum (600) and minimum
(400) is less than one fourth of the 10-bit dynamic range (256),
full 10-bit dynamic range will be preserved.
It must be noted that equations 4 and 5 should not in any way be
construed as limiting the scope of the invention. Rather, equations
4 and 5 are presented as only one of a plurality of linear
functions suitable for use in the invention. The invention may also
be practiced using non-linear functions (such as gamma correction
and companding functions). Moreover, the invention may be practiced
using a combination of linear and non-linear functions to optimize
data compaction. The linear and/or non-linear functions selected
will vary depending on the type of information stream being
processed, the typical distribution of parameters of interest
within the information elements of that stream, the amount of
dynamic range allowed for a given application, the processing
constraints of the encoder and/or decoder operating on the
information streams and other criteria.
To help ensure that the difference between the maximum and minimum
values remains below the threshold level, it is desirable to reduce
the size of the regions. However, a reduction in region size
necessarily results in additional maximum and minimum information
that must be identified and processed, though this overhead may not
be significant as will now be demonstrated.
The above-described method advantageously provides substantially
full dynamic range preservation of selected information element
parameters in an information frame. The cost, in terms of extra
bits necessary to implement the invention, e.g., the overhead due
to the use of minimum and maximum pixel values for each region of a
picture, will now be briefly discussed. Specifically, the
additional number of bits to be transported by, e.g., the
communications network 35 of FIG. 1 will be discussed.
Consider the case of preserving the 10-bit dynamic range of the
luminance parameter of a video information stream processed
according to an 8-bit dynamic range process. Assume that a small
region size is selected, such as a 16.times.16 block of 8-bit
pixels (monochrome). The 16.times.16 block of 8-bit pixels is
represented by 256*8 bits=2048 bits. Adding two 10-bit values, a
minimum and a maximum, to this block increases the number of bits
by 20 to 2068 bits, or an increase of about 1%. In return for this,
the pixel intensity resolution is never worse than 8 bits, and may
be as high as 10 bits, a factor of four improvement in the
intensity depth resolution.
Consider the case of a 10-bit digital video stream according to the
well known 4:4:4 format. In this case the luminance (Y) and color
difference (U, V) signals each have 10-bit dynamic range. Again,
assuming that a small region size is selected, such as a
16.times.16 block of 8-bit pixels. The 8-bit pixels are represented
by 256*8*3 bits=6144 bits. In this case also, adding six 10-bit
values, a minimum and a maximum for each of the luminance (Y) and
color difference (U, V) signals, to this block increases the number
of bits by 60 to 6204 bits, or an increase of about 1%. In return
for this, each of the luminance (Y) and color difference (U, V)
signals are never worse than 8 bits, and may be as high as 10 bits,
a factor of four improvement in the respective intensity and color
depth resolutions.
Returning now to the first case, if all the pixels were to be
represented by 10 bits, then the total number of bits would be
256*10=2560 bits. In other words, full 10-bit representation would
require 24% more bits than the regional coding described here.
Thus, the method provides a substantial improvement in dynamic
range without a correspondingly substantial increase in bit count.
Moreover, by utilizing the method within the context of
mass-produced encoder/decoder chipsets, such as the various
implementations of the MPEG and MPEG-like compression standards,
JPEG and JPEG-like compression standards (and other known
techniques) the method leverages the cost-savings of existing 8-bit
chipsets to provide a 10-bit (or higher) effective dynamic
range.
The above-described embodiments of the invention achieve the
desired result using linear compaction methods. However, in some
applications it is desirable to process information using
non-linear methods. For example, analog video signals are
non-linearly processed (i.e., "gamma corrected") to compensate for
non-linearity in, e.g., picture tubes in television sets.
Non-linear mapping methods according to the invention may be used
to implement gamma correction and other functions while preserving
the dynamic range of the underlying signal. Moreover, linear and
non-linear methods may be used together.
Another scenario appropriate for non-linear processing in the
mapping function occurs when there is a loss of accuracy because
the original range and the target range are too far apart, even
with the above-described intensity compaction methods. In this
case, non-linear mapping is used to preserve the original pixel
values (i.e., dynamic range) over some part of the range. This
situation is depicted below with respect to FIGS. 4A and 4B, where
the information located within a lower bit range (e.g., 0-131) is
illustratively deemed to be more important than the information
located within an upper bit range (e.g., 132-1023).
FIG. 4A depicts a diagram 4 illustrative of a non-linear encoding
function. The diagram comprises an original dynamic range 410A of
1024 bits and a target dynamic range 420A of 255 bits. A signal
430A, 440A having a 1024 bit dynamic range is remapped into the 255
bit dynamic range space in two segments. The first segment 430A
utilizes a substantially linear transfer function, while the second
segment 440A utilizes a compressed transfer function. That is, the
range of 0-131 in the original map is retained in the target map,
while the range of 132 to 1023 in the original map is compressed
into the 132-255 range of the target map.
FIG. 4B depicts a diagram illustrative of a non-linear decoding
function associated with the encoding function of FIG. 4A. Thus, to
retrieve, at a decoder, the information signal encoded according to
a remapping function having the transfer function depicted in FIG.
4A, the decoder implements a remapping function having the transfer
function depicted in FIG. 4B.
FIG. 5 depicts a high level function block diagram of an encoding
and decoding method and apparatus according to the invention.
Specifically, the encoding and decoding method and process
comprises a function mapper 530, which is responsive to an
information stream S1 received from, illustratively, a pixel source
510. The function mapper remaps the information stream S1 according
to various function criteria f.sub.c provided by a function
criteria source 520 to produce a remapped information stream S3 and
an associated map information stream S4.
The remapped information stream S3 is coupled to an encoder 540
that encodes the remapped information stream S3 to produce an
encoded information stream S5. The encoded information stream S5
and the map information stream S4 are transported to, respectively,
a decoder 550 and an inverse function mapper 560.
The decoder 550 decodes the transported and encoded information
stream to retrieve an information stream substantially
corresponding to the initial remapped information stream.
The inverse function mapper 560 performs, in accordance with the
transported map information stream S4, an inverse function mapping
operation on the retrieved stream to produce an information stream
substantially corresponding to the original information stream. It
must be noted that the information stream produced by the inverse
function mapper 560 may advantageously include linear and/or
non-linear modifications in furtherance of the specific application
(e.g., gamma correction and the like).
It should be noted that the function mapper 530 and inverse
function mapper 560 may be operated in substantially the same
manner as the region map and scale unit 10 and inverse region map
and scale unit 60 depicted in FIG. 1.
In one embodiment of the invention, the remapping function
performed by, e.g., the function mapper 530 or region map and scale
unit 10 performs a remapping function according to an arbitrary
function. An arbitrary function remapping of, e.g., pixel luminance
or chrominance parameters from an original dynamic range to a
target dynamic range may be represented by equation 6, where
TP=Target Pixel; OP=Original Pixel; TR=Target Range; OR=original
Range; MAX=maximum value; MIN=minimum value; and F=the arbitrary
function. TP=F(OP,MAX,MIN,TR) (eq. 6)
It is important to note that the function F may take a number of
forms and be implemented in a number of ways. For example, the
function F may implement: 1) a simple linear function such as
described above with respect to FIGS. 1-2; 2) a gamma correction
function that varies input video intensity levels such that they
correspond to intensity response levels of a display device; 3) an
arbitrary polynomial; or 4) a tabulated function (i.e., a function
purely described in terms of a lookup table, where each input bit
addresses a table to retrieve the contents stored therein.
In the case of remapping using a fixed gamma correction function, a
function of the following form may be implemented: TP=.left
brkt-bot.F[(OP-MIN).sup..gamma.*TR/(MAX-MIN).sup..gamma.]+0.5.right
brkt-bot. (eq. 7)
In the case of remapping using a polynomial segment, illustratively
a parabola (X.sup.2+X), a function of the following form may be
implemented, assuming that the polynomial segment is never be less
than 0 nor greater than the target range: TP=.left
brkt-bot.[(OP-MIN).sup.2+(OP-MIN)*TR/[(MAX-MIN).sup.2+(MAX-MIN)]+0.5.righ-
t brkt-bot. (eq. 8)
In the case of remapping using a tabulated function, the table
comprises an indexable array of values, where the index values are
the original range and the values in the table are included in the
target range. This allows any arbitrary mapping between the two
ranges. Unless, like gamma correction, that mapping is one-way only
(i.e., the remapping is not intended to be "unmapped"), then there
an inverse table at the decoder 550 or inverse map and scale unit
60 will restore the original information values.
It should be noted that the terms dynamic range enhancement stream
and map region identification stream are used in substantially the
same manner to describe information streams carrying auxiliary or
other data suitable for use in recovering at least a portion of the
dynamic range of an information stream processed according to the
invention.
Although various embodiments that incorporate the teachings of the
present invention have been shown and described in detail herein,
those skilled in the art can readily devise many other varied
embodiments that still incorporate these teachings.
* * * * *