U.S. patent application number 15/423299 was filed with the patent office on 2018-05-17 for method and system for screen correction.
The applicant listed for this patent is CHRISTIE DIGITAL SYSTEMS USA, INC.. Invention is credited to Ian Chadwyck FARAGHER, Nicholas David JANKOVIC, Kevin MOULE, Derek SCOTT, Daniel Thomson URQUHART, Peter Anthony VAN EERD.
Application Number | 20180139424 15/423299 |
Document ID | / |
Family ID | 58360819 |
Filed Date | 2018-05-17 |
United States Patent
Application |
20180139424 |
Kind Code |
A1 |
URQUHART; Daniel Thomson ;
et al. |
May 17, 2018 |
METHOD AND SYSTEM FOR SCREEN CORRECTION
Abstract
A method, system, and a computer readable medium for screen
correction is provided. The system includes a memory storage unit
for storing model content, a screen having screen parameters, an
input device for receiving the screen parameters, a correction
engine, and a projector. The method involves storing model content
on a memory storage unit, receiving screen parameters, generating
screen content, and projection at least a portion of the screen
content onto the screen. The computer readable medium encoded with
codes for directing a processor to carry out the method.
Inventors: |
URQUHART; Daniel Thomson;
(Kitchener, CA) ; FARAGHER; Ian Chadwyck;
(Kitchener, CA) ; SCOTT; Derek; (Kitchener,
CA) ; VAN EERD; Peter Anthony; (Guelph, CA) ;
JANKOVIC; Nicholas David; (Waterloo, CA) ; MOULE;
Kevin; (Kitchener, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHRISTIE DIGITAL SYSTEMS USA, INC. |
Cypress |
CA |
US |
|
|
Family ID: |
58360819 |
Appl. No.: |
15/423299 |
Filed: |
February 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62420947 |
Nov 11, 2016 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04N 9/3185 20130101;
H04N 9/3194 20130101; H04N 9/3147 20130101 |
International
Class: |
H04N 9/31 20060101
H04N009/31; H04N 13/02 20060101 H04N013/02 |
Claims
1. A system for screen correction, the system comprising: a memory
storage unit for storing content provided by a content producer,
wherein the content provided by the content producer is rendered to
be displayed in accordance with given model parameters; a screen
having screen parameters; an input device configured to receive the
screen parameters, wherein the input device periodically scans the
screen to determine the screen parameters; a correction engine in
communication with the memory storage unit and the input device,
the correction engine configured to process the content provided by
the content producer and the screen parameters to generate screen
content; and a first projector in communication with the correction
engine, the first projector configured to receive a first portion
of the screen content and to project the first portion the screen
content onto the screen.
2. The system of claim 1, further comprising a second projector in
communication with the correction engine, the second projector
configured to receive a second portion of the screen content and to
project the second portion of the screen content onto the screen,
wherein the first portion of the screen content and the second
portion of the screen content overlap on the screen.
3. The system of claim 2, wherein the screen is non-planar.
4. The system of claim 3, wherein the screen is curved.
5. The system of claim 1, wherein the screen includes a plurality
of topographical reference points.
6. The system of claim 5, wherein the plurality of topographical
reference points defines a plurality of facets.
7. The system of claim 1, wherein the input device is a camera
configured to measure the screen parameters.
8. The system of claim 7, wherein the camera measures the screen
parameters using a calibration pattern projected by the first
projector.
9. (canceled)
10. The system of claim 1, wherein the input device is a 3D
scanning unit.
11. A method of screen correction, the method comprising: storing
content provided by a content producer on a memory storage unit,
wherein the content provided by the content producer is rendered to
be displayed in accordance with given model parameters; scanning a
screen to determine screen parameters periodically with an input
device; receiving, at a correction engine, the screen parameters of
the screen from the input device; generating screen content by
processing the content provided by the content producer and the
screen parameters at the correction engine; and projecting at least
a first portion the screen content onto the screen using a first
projector in communication with the correction engine.
12. The method of claim 11, further comprising projecting a second
portion of the screen content onto the screen using a second
projector in communication with the correction engine, wherein the
first portion of the screen content and the second portion of the
screen content overlap on the screen.
13. The method of claim 12, wherein projecting the first portion
and the second portion of the screen content the screen comprises
projecting on a non-planar surface.
14. The method of claim 11, further comprising defining a plurality
of facets using a plurality of topographical reference points on
the screen.
15. The method of claim 11, wherein receiving the screen parameters
comprises measuring the screen parameters with the input
device.
16. The method of claim 15, further comprises projecting a
calibration pattern to measure the screen parameters.
17. (canceled)
18. The method of claim 11, wherein the input device is a
camera.
19. The method of claim 11, wherein the input device is a 3D
scanning unit.
20. A non-transitory computer readable medium encoded with codes,
the codes for directing a processor to: store content provided by a
content producer on a memory storage unit, wherein the content
provided by the content producer is rendered to be displayed in
accordance with given model parameters; scan a screen to determine
screen parameters periodically with an input device; receive the
screen parameters of the screen from the input device; generate
screen content by processing the content provided by the content
producer and the screen parameters at a correction engine; and
project at least a first portion the screen content onto the screen
using a first projector in communication with the correction
engine.
Description
FIELD
[0001] The present specification relates generally to projector
systems, and more particularly to projector systems displaying
content on a specific screen.
BACKGROUND
[0002] Prior to displaying content on a screen, the content is
generally rendered for a particular setup. Content displayed on the
screen may still appear misaligned on the screen even following a
very good calibration. Screen position and geometry are critical
when content overlaps from two projectors located at different
positions.
SUMMARY
[0003] In accordance with an aspect of the invention, there is
provided a system for screen correction. The system includes a
memory storage unit for storing model content. The model content is
rendered to be displayed in accordance with model parameters. The
system further includes a screen having screen parameters. The
system also includes a correction engine in communication with the
memory storage unit and the input device. The correction engine is
configured to process the model content and the screen parameters
to generate screen content. Additionally, the system includes a
first projector in communication with the correction engine. The
first projector is configured to receive a first portion of the
screen content and to project the first portion the screen content
onto the screen.
[0004] The system may further include a second projector in
communication with the correction engine. The second projector may
be configured to receive a second portion of the screen content and
to project the second portion of the screen content onto the
screen, wherein the first portion of the screen content and the
second portion of the screen content overlap on the screen.
[0005] The screen may be non-planar.
[0006] The screen may be curved.
[0007] The screen may include a plurality of topographical
reference points.
[0008] The plurality of topographical reference points may define a
plurality of facets.
[0009] The input device may be a camera configured to measure the
screen parameters.
[0010] The camera may measure the screen parameters using a
calibration pattern projected by the first projector.
[0011] The camera may periodically scan the screen to determine the
screen parameters.
[0012] The input device may be a 3D scanning unit.
[0013] In accordance with an aspect of the invention, there is
provided a method of screen correction. The method involves storing
model content on a memory storage unit, wherein the model content
is rendered to be displayed in accordance with model parameters.
The method also involves receiving screen parameters of a screen
via an input device. In addition, the method involves generating
screen content by processing the model content and the screen
parameters at a correction engine. The method further involves
projecting at least a first portion the screen content onto the
screen using a first projector in communication with the correction
engine.
[0014] The method may further involve projecting a second portion
of the screen content onto the screen using a second projector in
communication with the correction engine, wherein the first portion
of the screen content and the second portion of the screen content
overlap on the screen.
[0015] Projecting the first portion and the second portion of the
screen content the screen may involve projecting on a non-planar
surface.
[0016] The method may further involve defining a plurality of
facets using a plurality of topographical reference points on the
screen.
[0017] Receiving screen parameters may involve measuring the screen
parameters with the input device.
[0018] The method may further involve projecting a calibration
pattern to measure the screen parameters.
[0019] The method may further involve periodically scanning the
screen to determine the screen parameters.
[0020] The input device may be a camera.
[0021] The input device may be a 3D scanning unit.
[0022] In accordance with an aspect of the invention, there is
provided a non-transitory computer readable medium encoded with
codes. The codes direct a processor to store model content on a
memory storage unit, wherein the model content is rendered to be
displayed in accordance with model parameters. The codes further
direct the processor to receive screen parameters of a screen via
an input device. In addition, the codes further direct the
processor to generate screen content by processing the model
content and the screen parameters at a correction engine.
Furthermore, the codes further direct the processor to project at
least a first portion the screen content onto the screen using a
first projector in communication with the correction engine.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Reference will now be made, by way of example only, to the
accompanying drawings in which:
[0024] FIG. 1 is a schematic drawing of a system in accordance with
an embodiment;
[0025] FIG. 2 is a schematic drawing of a system of FIG. 1 in
operation with the correction engine deactivated;
[0026] FIG. 3 is a schematic drawing of a system of FIG. 1 in
operation with the correction engine activated;
[0027] FIG. 4 is a schematic drawing of a system in accordance with
another embodiment;
[0028] FIG. 5 is flow chart of a method in accordance with an
embodiment;
[0029] FIG. 6 is a schematic drawing of a system in accordance with
another embodiment; and
[0030] FIG. 7 is a schematic drawing of a system in accordance with
another embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0031] Referring to FIG. 1, a system for screen correction is
generally shown at 50. It is to be understood that the system 50 is
purely exemplary and that it will become apparent to those skilled
in the art that modifications to the system 50 are contemplated.
Examples of variations are discussed in greater detail below and
various components can be substituted and/or added depending on the
requirements of the system 50. The system 50 is generally
configured to project content from at least one projector onto a
screen.
[0032] In the present embodiment, the system 50 includes projectors
55-1 and 55-2 (generically, projector 55 and collectively
projectors 55, this nomenclature is used elsewhere herein), a
screen 60, a memory storage unit 65, an input device 70, and a
correction engine 75. It is to be appreciated by a person of skill
in the art with the benefit of this description that the system 50
is not necessary assembled by a single party and various components
can be sourced from various sources specialized in the manufacture
of the component. In addition, the geometry of the system 50 is not
particularly limited and can be varied based on the application as
discussed in greater detail below. Furthermore, the system 50 can
be operated using one or more processors in communication with the
various components.
[0033] The projector 55 is generally configured to receive content
for projecting images. It is to be understood by a person of skill
in the art with the benefit of this description that the projector
55 is not particularly limited and that several variations are
contemplated. For example, in the present embodiment the projector
is a digital multimirror device projector. In other embodiments,
the projector can be substituted with another type of projector
such as an analog projector, a digital projector, a cinema
projector, an LCOS (Liquid Crystal on Silicon) based projector, or
any other device capable of outputting a projection of a raster
image.
[0034] The screen 60 is generally configured to receive light from
the projectors 55 and to display a generated image to an audience.
The screen 60 is not particularly limited and can be made from any
type of material or coating suitable for the application. In the
present embodiment, the screen 60 is non-planar. In particular, the
screen 60 is curved with an approximate spherical curvature.
However, in other embodiments, the screen 60 can have another
geometry. Although FIG. 1 illustrates the screen receiving an image
from the projectors and reflecting the light to the audience (front
projection), other embodiments can use a screen that receives light
from behind the screen relative to the audience (back projection).
It is to be appreciated by a person of skill with the benefit of
this description that the screen 60 is generally constructed to
typical construction tolerances, such as one percent. For example,
the screen 60 can be approximately 25 meters wide and have a
tolerance of up to 25 centimeters for any given dimension.
Accordingly, the curvature of the screen 60 and the edges of the
screen 60 can be offset by a substantial distance relative to the
typical 3 millimeter pixel size for a screen of this size.
[0035] Accordingly, the actual screen parameters of the screen 60
can be different from the dimensions of the screen 60 from the
original blueprints. This is typical of most construction projects
and would vary based on the skills and tendencies of the workers
building the screen. In addition, due to external conditions, the
screen 60 can shift from the original position after construction.
For example, temperature fluctuations can cause the screen 60 or
components of the screen 60, such as joints, to expand and
contract. As another example, the screen 60 can settle over time or
from vibrations such as vehicle traffic or heavy machinery within
the vicinity. Therefore, the actual screen parameters, which can be
obtained using a 3D mapping of various points of the screen
relative to the projector, can be different from the 3D model
parameters from the original blueprints.
[0036] The screen parameters are not particularly limited. For
example, screen parameters can include the dimensions of the
screen, the curvature of the screen, the location of predetermined
topographical reference points, or whether the screen is a front
projection screen or back projection screen.
[0037] The memory storage unit 65 is generally configured to store
model content. Model content refers to content provided by a
content producer that has been rendered for the system 50 in
accordance with model parameters, which are the assumed parameters
of the system 50 based on original blueprint specifications or an
approximated ideal screen model. The memory storage unit 65 is not
particularly limited and can include non-volatile memory, such as
flash drives, and optical or magnetic discs, or volatile memory.
The memory storage unit 65 can also be removeable such as an
optical disc or a flash drive such that the content can be used as
part of multiple systems at different location or such that the
content can be easily delivered from a content producer to the
system 50. In other embodiments, the memory storage unit 65 can
also receive the content from a network. It is to be appreciated
that the memory storage unit 65 can be used for any other purpose
in the system 50. For example, the memory storage unit 65 can be
used to store codes for operating the system 50. As another
example, the memory storage unit 65 can be used to store actual
screen data as discussed in greater detail below.
[0038] In the present embodiment, the content stored on the memory
storage unit 65 is configured to be used on the system 50. For
example, the content can include two portions. The first portion
can be configured to be projected by the projector 55-1 and the
second portion can be configured to be projected by the projector
55-2. The content stored on the memory storage unit 65 is rendered
based on model parameters provided to the producer. In the present
embodiment, the model parameters are the dimensions from the
original blueprints of the system 50.
[0039] In other embodiments, it is to be appreciated by a person of
skill with the benefit of this description that the model
parameters can be an assumed shape that approximated the design
parameters of the system 50. For example, if the screen 60 were
originally designed to have a parabolic curvature, the model
parameters can be dimensions of a spherical curvature that
approximates the originally designed to have a parabolic curvature.
This approximation can be made to simplify the rendering process of
the content such that less computational resources are required to
produce the content. For example, parametric screens can use models
based on standard geometries, such as planes, spheres, or
cylinders. Other examples can use mesh screens defined as a dense
3D mesh, such as one imported from a 3D CAD package.
[0040] The input device 70 is generally configured to receive the
actual screen parameters. The manner by which the input device 70
receives the actual screen parameters is not particularly limited.
In the present embodiment, the actual screen parameters are
uploaded from a flash drive such that the input device 70 is a
flash drive reader. In other embodiments, the input device 70 can
be a user input device such as a keyboard for manually entering the
actual screen parameters. In further embodiments, the input device
70 can be a device configured to measure the actual screen
parameters, such as a 3D scanning unit, for example, a laser
scanner or a camera.
[0041] The correction engine 75 is generally configured to process
the model content stored on the memory storage unit 65 using the
actual screen parameters received from the input device 70 to
generate screen content for projecting a corrected image onto the
screen 60 which accounts for differences between the model
parameters and the actual screen parameters. It is to be
appreciated that in a variation, the correction engine 75 can also
receive the actual screen parameters stored in the memory storage
unit 65 if it was previous entered. In further embodiments, the
correction engine 75 can include a separate memory storage unit
(not shown) for storing actual screen parameters.
[0042] In the present embodiment, there are two projectors 55-1 and
55-2 configured to receive content for projecting images as shown
in FIG. 1. The model content intended to be projected onto the
screen can be divided into two portions. The projector 55-1 is
configured to project a first portion of the content and the
projector 55-2 is configured to project a second portion of the
content where the two portions can be combined to form the overall
content. In the present embodiment, the portion projected by the
projector 55-1 overlaps with the portion projected by the projector
55-2 within an overlap region 100.
[0043] Referring to FIG. 2, the operation of the system 50 is
illustrated with the correction engine 75 deactivated. The model
content stored on the memory storage unit 65 is rendered to be
displayed on a model screen 62. As shown, a point 105 in the
overlap region 100 would receive light from the projectors 55-1 and
55-2. Since the content was rendered from the content producer
using model parameters associated with the model screen 62, the
point 105 would separate and hit the screen 60 at two locations
110-1 and 110-2. Accordingly, when viewed by an audience, this
would produce a double image on the screen 60 and therefore
diminish the user experience.
[0044] Referring to FIG. 3, the operation of the system 50 is
illustrated with the correction engine 75 activated. As shown, the
point 105 in the overlap region 100 is mapped from the model screen
62 to the screen 60 at a single location 110. In the present
embodiment, the point is mapped to a (u, v) Cartesian coordinate
system (UV mapped). However, it is to be appreciated that the
manner by which the point is translated from the model screen 62 to
the screen 60 is not particularly limited. Since the point 105
intended for the model screen 62 now appears at a single point on
the screen 60, the double image in the overlap region 100 that
would have been generated without the correction engine 75 (such as
shown in FIG. 2) would not be present. However, it is to be
understood that by mapping the screen content onto the screen 60,
some warping of images may occur. Depending on the amount of
deviation of the screen 60 from the model screen 62, the amount of
warping can be small or unnoticeable to an audience, whereas a
double image would be very noticeable since the image is no longer
sharp. Furthermore, it is to be appreciated that the mapping can
also account for the location of the audience to reduce the effects
of image warping. For example, the mapping can be performed
relative to an eye-point. In other embodiments, the mapping can be
done relative to the surface normal of the screen 60 or using
topographical reference points as discussed in greater detail
below. It is to be appreciated by a person of skill in the art that
a mapping derived from the eye-point is more suitable when the
audience will primarily view the display from a small area known in
advance, such as in a flight simulator. Other approaches, such as
using the screen normal or using topographical reference points to
map between screens are more appropriate when the audience is not
constrained to a small viewing area, such as for digital signage
applications.
[0045] It is to be appreciated by a person of skill with the
benefit of this description that the system 50 can be modified to
also reduce the appearance of imperfections in the screen.
Referring to FIG. 4, a system 50' is generally shown with an
imperfect screen 60'. The screen 60' can be designed to have a
smooth curvature, but manufacturing defects or subsequent damage
can cause the screen to have the warped shape shown in FIG. 4. The
system 50' also includes a projector 55', a memory storage unit
65', an input device 70', and a correction engine 75', each of
which function similar to the corresponding components from FIG. 1.
It is to be appreciated that the model content store on the memory
storage unit 65' is rendered to be displayed on a model screen 62'.
Deviations of the screen 60' from the model screen 62' results in
warping as an image point intended to be displayed on the model
screen 62' at point 105' would appear at point 110' on the screen
60' viewed from an eyepoint 300' when the correction engine 75' is
deactivated. When the correction engine 75' is activated, the point
110' is translated to the point 120', which would be at the same
position as the intended point 105' when viewed from the eyepoint
300' and thus reducing the appearance of the imperfection of the
screen 60'.
[0046] Referring to FIG. 5, a method of screen correction is
represented in the form of a flow-chart and indicated generally at
500. For illustrative purposes, it can be assumed the method 500 is
implemented using the system 50 described above. However, it is to
be understood that the method 500 is not limited to the system 50
and can be implemented on a wide variety of systems. Furthermore,
the following discussion of the method 500 will lead to further
understanding of the system 50 and its various components. Although
some blocks of the method 500 are described below as occurring
within certain components of the system 50, it is to be understood
that the system 50 or the method 500 can be varied, and need not
work exactly as discussed herein in conjunction with each
other.
[0047] Beginning at block 510, model content is stored on the
memory storage unit 65. The manner by which the model content is
obtained or transferred to the memory storage unit 65 is not
particularly limited. For example, the model content can be
downloaded via a network connection or transferred manually using a
portable computer readable storage medium, such as an optical disc
or a flash drive.
[0048] Block 520 involves receiving screen parameters of the screen
60. The manner by which the screen parameters are obtained are not
particularly limited. In the present embodiment, the screen
parameters are obtained by performing a laser scan of the physical
screen 60 and manually entering the information via the input
device 70.
[0049] Block 530 comprises generating screen content based on the
model content stored in the memory storage unit 65 using the screen
parameters received at block 520. In the present embodiment, the
correction engine 75 uses points from the model content and maps
the model content onto the screen 60 (as determined from the screen
parameters) using a UV layout. The UV layouts can be automatically
generated from the projector centric channel extents or any other
content channel definition. The UV layouts can be saved in a lookup
table where model content can be readily converted into screen
content using substantially less computation resources than if the
content were to be re-rendered for the screen 60.
[0050] Next, block 540 involves projecting the screen content onto
the screen 60. The manner by which the screen content is projected
is not particularly limited. In the present embodiment, the screen
content is projected by the projectors 55, where the screen content
is corrected for deviations of the physical screen 60 from the
model screen 62 such that the image appears sharper by reducing
double imaging.
[0051] Referring to FIG. 6, another embodiment of a system for
screen correction is generally shown at 50a. In the present
embodiment, like components of the system 50a bear like reference
to their counterparts in the system 50, except followed by the
suffix "a". In the present embodiment, the system 50a includes
projectors 55a-1 and 55a-2, a screen 60a, a memory storage unit
65a, cameras 70a-1 and 70a-2, and a correction engine 75a.
[0052] In the present embodiment, the cameras 70a-1 and 70a-2 are
used to provide the screen parameters to the correction engine 75a.
For example, the cameras 70a-1 and 70a-2 can be used to detect a
calibration pattern projected onto the screen 60a to determine the
screen parameters. The manner by which the calibration pattern is
projected is not particularly limited. For example, the calibration
pattern can be projected using one or both of the projectors 55a
and the screen parameters measured using the cameras 70a as a
stereo pair. In the other embodiments, the calibration pattern can
be projected using an additional projector configured specifically
for projecting calibration patterns.
[0053] It is to be appreciated by a person skilled in the art that
the calibration pattern need not be visible to a human eye. In some
embodiments, the calibration pattern can be projected onto the
screen 60a in an ultraviolet or infrared spectrum such that the
audience would not be able to view the calibration process. In
other embodiments, the test pattern can be integrated into the
visible spectrum temporarily over a very short period of time to
make the test pattern substantially invisible to a human eye. By
using an invisible calibration pattern, the cameras can be
collecting data during the projection of content on the screen 60a
without an audience noticing and thus provide the ability to adjust
for variations on the fly on a screen 60a that may move slightly
due to vibrations or other factors during the projection of
content. Accordingly, the cameras 70a can be configured to scan the
screen periodically to determine screen parameters.
[0054] It is to be re-emphasized that the system 50a described
above is a non-limiting representation. For example, the system 50a
can be modified to be function with a single camera measuring a
point cloud from a single projector such that the camera and
projector form a stereo pair. In addition, the camera 70a can be
substituted with another input device for periodic scanning.
[0055] Referring to FIG. 7, another embodiment of a system for
screen correction is generally shown at 50b. In the present
embodiment, like components of the system 50b bear like reference
to their counterparts in the system 50, except followed by the
suffix "b". In the present embodiment, the system 50b includes a
projector 55b, a screen 60b, a memory storage unit 65b, an input
device 70b, and a correction engine 75b.
[0056] In the present embodiment, the system 50b includes a single
projector 55b. The system 50b further includes a screen 60b having
a 3D shape. In particular, the screen 60b includes a plurality of
planar facets 200b at various angles to form a ball shape. It is to
be appreciated that where two planar facets 200b meet, a sharp edge
comprising a plurality of topographical reference points 210b is
formed around each facet 200b.
[0057] In the present embodiment, the memory storage unit 65b can
include model content for displaying a plurality of images on the
screen 60b such that each facet 200b is to display one image or a
well-defined region within a larger image. Accordingly, any
deviation in the screen 60b from the model parameters would result
in images extending beyond each facet boundary defined by the
topographical reference points 210b. Therefore, the correction
engine 75b can be used on the model content to generate screen
content that is warped to fit on the facets 200b of the screen
60b.
[0058] It is to be understood that combinations, variations and
subsets of the embodiments and teachings herein are contemplated.
For example, it is to be appreciated that one or more of the
components can be integrated within a projector, such as the
projector 55. As another example of a variation, the model content
stored on the memory storage unit 65 need not be provided by a
content provider and can be rendered locally using model parameters
by system based on camera input.
[0059] Various advantages will now be apparent to a person of skill
in the art. Of note is the ability to apply a screen correction to
rendered content at the location where the system 50 is set up
using very little computational resources. This provides the
advantage of not requiring a custom rendering for each site which
may have similar parameters with minor deviations introduced during
construction or though other environmental factors. Alternatively,
if the system 50 includes parameters close to an ideal system where
computational resources would be significantly reduced, the model
content can be rendered based on the model parameters that reduce
the use of computational resources to provide a faster rendering
which can be subsequently corrected using the system 50.
[0060] While specific embodiments have been described and
illustrated, such embodiments should be considered illustrative
only and should not serve to limit the accompanying claims.
* * * * *