APPARATUS AND METHOD THAT PRESENT PROJECTION IMAGE
CROSSREFERENCE TO RELATED APPLICATION
The present invention contains subject matter related to
Japanese Patent Application JP 2006-064568 filed in the Japanese
Patent Office on March 9, 2006, the entire contents of which
being incorporated herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
This invention relates to an apparatus and a method that
present a projection image including sections of the image which
a plurality of projectors project on a screen.
Description of Related Art
Japanese Patent Application Publication No. 2004-15204
has disclosed a multi-projection system that projects an image
on a screen by using a plurality of projectors.
FIG. 1 is a schematic view of a multi-projection system
300 as related art. This multi-projection system 300 is
constituted of a total of 12 projectors 301_i to 301-i2 that are
arranged in a matrix of four projectors per row and three
projectors per column.
FIG. 2 shows an example of a projection image 302 which
these 12 projectors 301-1. to 301.12 project onto a screen 310.
This projection image 302 is divided into 12 equal sections 302.
i to 302-12, and each section is a section (projected section) of
the projection image 302 that each of the projectors 301_i to
301-12 projects onto the screen 310. In FIG. 2, broken lines
represent boundaries between adjacent sections among the 12
sections 302_! to 302.12.
FIG. 3 clearly shows a relationship between each of the
projectors 301_i to 301.12 and their corresponding sections 302-i
to 302-12 of the projection image in which the displayed
projection image is omitted from each of the sections. It is to
be noted that slightly overlapping parts (blending regions)
practically exist between the adjacent sections projected by the
adjacent projectors but these overlapping parts is omitted
herein.
SUMMARY OF THE INVENTION
In the multi-projection system 300 shown in FIG. 1, the
section projected by an individual projector does not depend on
the contents of the image 302 being projected and thus, this
section is previously set and made unchanged. In other words,
the number of projectors assigned per unit area of the screen
310 is constant at any parts on the screen, and the resolution
(resolving power) of the display is uniform all over the screen.
However, in general, an image includes a section thereof
with a large amount of information (places with fine details,
for example, trees, buildings and structures) and a section
thereof with a small amount of information (flat places with few
details, for example, cloudless sky), as shown in FIG. 2.
In the multi-projection system 300 shown in FIG. 1,
regardless of the unevenness in the amount of information in
such an image, all the places in the image are presented at a
constant resolution. In other words, a section showing a sky,
which has a small amount of information per unit area as well as
a section showing trees, buildings and structures, which has a
large amount of information per unit area, are presented by
using the same number of projectors.
It is desirable to provide an apparatus and a method
that present a projection image having high presentation
resolution without increasing the number of projectors to be
used.
According to an embodiment of the present invention,
there is provided an apparatus that presents a projection image.
The apparatus contains a screen and plural projectors, each of
which projects a section of the projection image onto the screen
to reproduce the projection image. The apparatus also contains
a projected-section-determining unit that determines as a
projected section the section of the projection image, based on
an input image signal. The section of the projection image
corresponds to a part of the screen onto which each of the
projectors projects the section of the projection image therefor.
The apparatus further contains an image-signal-generating unit
that generates an image signal corresponding to the section of
the projection image which each of the projector projects onto
the part of the screen, based on the input image signal and the
projected section which has been determined by the projectedsection-
determining unit. The apparatus additionally contains a
projectors-controlling unit that controls the projectors,
respectively, to adjust any one of centers and ranges of the
projections by the projectors based on the projected section
which has been determined by the projected-section-determining
unit.
In this embodiment of the present invention, plural
projectors, each of which projects the section of the projection
image onto the screen, are provided to reproduce the projection
image on the screen. On the basis of the input image signal, a
projected-section-determihing unit determines as a projected
section the section of the projection image corresponding to a
part of the screen onto which each of the projectors projects
the section of the projection image therefor. In this
embodiment, the sections of the projection image to be projected
by the projectors, respectively, are determined such that the
number of projectors assigned to a section of the projection
image containing a large amount of information per unit area is
increased while the number of projectors assigned to a section
of the projection image containing a small amount of information
per unit area is decreased.
For example, on the basis of the input image signal, the
local dynamic range is calculated by the projected-sectiondetermining
unit for each pixel by using a signal relative to
the pixel and a predetermined number,of other pixels adjacent to
the pixel. On the basis of the local dynamic ranges for each of
the pixels, the section of the projection image to be projected
by each of the plural projectors is determined as the projected
section such that the sum total of the local dynamic ranges for
all the projected sections can be equal.
In this embodiment, as the plural projectors are
arranged, for example, in a matrix of rows and columns, the
section of the projection image to be projected by the
projectors will be determined as follows. At first, the local
dynamic range is obtained for each pixel by using a target pixel
and a predetermined number of other pixels adjacent to the
target pixel. Then, on the basis of the local dynamic range for
each pixel, every horizontal, line where the accumulated sum of
the local dynamic ranges equals the quotient of the sum total of
the local dynamic ranges for all the pixels divided by the
number of projectors per the column is determined as a vertical
section boundary. Likewise, on the basis of the local dynamic
range for each pixel, every vertical line where the accumulated
sum of the local dynamic ranges equals the quotient of the sum
total of the local dynamic ranges for all the pixels divided by
the number of projectors per the row is determined as a
horizontal section boundary. In this moment, the horizontal and
vertical section boundaries, which define the sections of the
projection image to be projected by the projectors, are
respectively continuous.
For example, it is possible that all the pixels are set
as pixels belonging to each vertical section defined by the
vertical section boundaries delimited as described above, and
that horizontal section boundaries are then delimited for each i - i
vertical section. In this moment, the vertical section
boundaries, which define the, sections to be projected by the
projectors, respectively, are, continuous, but the horizontal
section boundaries are not continuous and are positioned
different for each vertical section.
It is also possible that, conversely, all the pixels are
set as pixels belonging to each horizontal section defined by
the horizontal section boundaries delimited as described above,
and that vertical section boundaries are then delimited for each
horizontal section. In this moment, the horizontal section
boundaries, which define the sections to be projected by the
projectors, respectively, are continuous, but the vertical
section boundaries are not continuous and are positioned
different for each horizontal section.
Also, preferably, for example, on the basis of the input
image signal, the amount of image information is calculated for
each vertical strip aligned in a horizontal direction as well as
the amount of image information is calculated for each
horizontal strip aligned in..the vertical direction. On the
basis of the amounts of image information for each of the strips,
the section of the projection image to be projected by each of
the projectors is determined as the projected section such that
an equal amount of image information is distributed for each
section.
In this case, for example, as plural projectors are
arranged in a matrix of rows and columns, the section of the
projection image to be projected by each of the projectors will
be determined as follows. At first, the amount of image
information is calculated for each vertical strip aligned in the
horizontal direction by using plural.bandwidth-compression image
signals which are bandwidth-limited horizontally at plural
levels and an original image signal thereof. Then, on the basis
of the amount of image information for each vertical strip, a
horizontal section boundary is delimited by every predetermined
vertical line where the accumulated sum of the amounts of image
information equals a quotient of the sum total of the amounts of
image information for all the vertical strips divided by the
number of projectors per the row
Likewise, the amount of image information is calculated
for each horizontal strip aligned in the vertical direction by
using plural bandwidth-compression image signals which are
bandwidth-limited vertically at plural levels and the original
image signal thereof. Then, on the basis of the amount of image
information for each horizontal strip, a vertical section
boundary is delimited by every predetermined horizontal line
such that the accumulated sum of the amounts of image
information equals the quotient of the sum total of the amounts
of image information for all the horizontal strips divided by
the number of projectors per the column. In this moment, the
horizontal and vertical section boundaries, which define the
sections of the projection image to be projected by the
projectors, respectively, are continuous.
For example, all the vertical strips are set as vertical
strips belonging to the respective vertical sections defined by
the vertical section boundaries, which are delimited as
described above, and then horizontal section boundaries are
delimited for each vertical section. In this moment, the
vertical section boundaries, which define the sections of the
projection image to be projected by the projectors, respectively,
are continuous, but the horizontal section boundaries are not
continuous and are positioned different for each vertical
section.
Conversely, all the horizontal strips are set as
horizontal strips belonging .to all the horizontal sections
defined by the horizontal section boundaries, which are
delimited as described above, . and then vertical section
boundaries are delimited for each horizontal section. In this
moment, the horizontal section boundaries, which define the
sections of the projection image to be projected by the
projectors, respectively, are continuous, but the vertical
section boundaries are not continuous and are positioned
different for each horizontal section.
According to another embodiment of this invention, there
is provided a method that presents a projection image on a
screen by projecting separate sections of the projection image
on the screen from plural projectors. The method includes the
steps of: determining as a projected section each of the
sections of the projection image to be projected on the screen
by each of the projectors, based on an input image signal;
generating an image signal corresponding to each of the section
of the projection image to be projected on the screen by each of
the projectors, based on the input image signal and the
projected section which has been determined at the above
determining step; and controlling the projectors to adjust any
one of centers and ranges of projections by the projectors based
on the section of the projection image determined at the above
determining step.
Thus, on the basis of the sections of the projection
image projected by the respective projectors, which are
determined as described above, an image signal that corresponds
to each of the sections of the projection image to be projected
on the screen by the projectors, respectively, is generated from
the input image signal. Each projector receives its
corresponding image signal which is generated in this way, to
project the respective sections of the projection image.
On the basis of the sections of the projection image to
be projected by the projectors, respectively, which are
determined as described above, the projectors are controlled so
that the centers and/or ranges of the projections by the
projectors can be adjusted. Displacement of the centers of the
projections by the projectors can be achieved by, for example, a
lens-shift mechanism or a mechanism that uses a mirror. In
addition, change of the projection ranges by the projectors can
be achieved by, for example, a zoom mechanism and an aspectratio
change mechanism that uses a cylindrical mirror or a
cylindrical lens. Adjusting any one of the centers and ranges
of the projections by the projectors allows the sections of the
projection image to be projected onto their proper parts of the
screen.
As described above, according to the embodiments of the
present invention, the sections of the projection image to be
projected on the screen by the plural projectors, respectively,
are determined on the basis of the input image signal, and the
image signal for each of the projectors is generated on the
basis of the section of the projection image determined for each
of the projectors. Furthermore, the centers and/or ranges of
the projections by the projectors are adjusted such that the
number of projectors assigned to a section of projection image
containing a large amount of information per unit area of the
projection image is increased while the number of projectors
assigned to a section of the projection image containing a small
amount of information per unit area of the projection image is
decreased. This enables any high presentation resolution to be
achieved without increasing the number of projectors.
The concluding portion of this specification
particularly points out and directly claims the subject matter
of the present invention. However, those skilled in the art
will best understand both the organization and method of
operation of the invention, together with further advantages and
objects thereof, by reading the.remaining portions of the
specification in view of the accompanying drawing(s) wherein
like reference characters refer to like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a multi-projection system
as related art;
FIG. 2 is a diagram for showing a projection image and
its sections projected by the corresponding projectors;
FIG. 3 is a diagram for showing a relationship between
each of the projectors and their corresponding section of the
projection image;
FIG. 4 is a schematic view of an embodiment of a multiprojection
system according to the invention;
FIG. 5 is a diagram for showing a projection image and
its sections projected by the corresponding projectors;
FIG. 6 is a diagram for showing a relationship between
each of the projectors and their corresponding section of the
projection image;
FIG. 7A is a block diagram for showing a configuration
of the multi-projection system, and FIG. 7B is a block diagram
for showing a configuration of the projected-section-determining
unit;
FIGS. 8A and 8B are diagrams each for describing a
method that generates image signals that are supplied to the
respective projectors;
FIG. 9 is a diagram for describing a displacement of a
center of projection;
FIG. 10 is a diagram for describing a change in the
projection range;
FIGS. 11A and 11B are diagrams each for describing a
displacement of the center of the projection by a lens-shift
mechanism;
FIG. 12 is a diagram for describing a displacement of
the center of the projection by a mechanism incorporating a
mirror;
FIGS. 13A and 13B are diagrams each for describing image
distortion and a process for canceling it;
FIG. 14 is a diagram for showing that a range of the
projection can be adjusted arbitrarily by controlling the aspect
ratio and the zoom rate;
FIG. 15 is a diagram for showing a local dynamic range
(local DR) for each pixel, which range is used for determining
the section of the projection image to be projected by each of
the projectors;
FIGS. 16A and 16B are diagrams each for describing the
sum total of the local DRs for the whole projection image;
FIGS. 17A and 17B are diagrams each for describing a
method for determining the vertical section boundaries by using
the local DRs;
FIG. 18 is a flowchart for showing steps of determining
the section of the projection image to be projected by each of
the projectors (first method);
FIG. 19 is a diagram for describing the information on
the centers and ranges of the projection by each projector;
FIG. 20 is a diagram for describing generation of
bandwidth-compression image signals that are used to determine
the section of projection image to be projected by each
projector;
FIG. 21 is a diagram for showing a property of a
horizontal low pass filter (LPF) for generating horizontal
bandwidth-compression image signals;
FIG. 22 is a diagram for describing generation of a
remainder for each of the strips;
FIGS. 23A to 23D are graphs each for showing a
relationships between the remainder and the compression factor
1/b for each of the strips;
FIG. 24 is a graph for showing a relationship between
values of the remainder and those of the compression factor 1/b
for the respective strips;
FIG. 25 is a graph for showing a relationship between
the mean value of the compression factor 1/b for each of the
strips and the remainder at each value of the remainder;
FIGS. 26A and 26B are diagrams each for describing how
the horizontal width of each of the strips is determined by
using the compression factor 1/b that corresponds to the
remainder used for the strip;
FIG. 27 is a block diagram for showing a configuration
of another projected-section-determining unit;
FIGS. 28A and 28B are diagrams each for describing a
method for determining horizontal section boundaries by using
the horizontal widths of the respective strips;
FIG. 29 is a flowchart for showing steps of determining
the section of the projection image to be projected by each of
the projectors (second method);
FIG. 30 is a diagram for showing another example of
determination of the sections of the projection image projected
by the respective projectors; and
FIG. 31 is a diagram for showing further example of
determination of the sections of the projection image projected
by the respective projectors.
DESCRIPTION OF PREFERRED EMBODIMENTS
The following will describe preferred embodiments
according to the invention. FIG. 4 is a schematic view of a
multi-projection system (apparatus that presents a projection
image) 100 as an embodiment of the invention.
13
This multi-projection system 100 is constituted of a
total of 12 projectors 101.i to 101.12 arranged in a matrix of
four projectors per row and three per column.
FIG. 5 shows an example of a projection image 102 that
these 12 projectors 101-1 to 101.12 project onto a screen 110.
This projection image 102 is divided into 12 sections 102-i to
102-12, and each section is an image section (projected section)
that is projected onto the screen 110 by each of the respective
projectors. In FIG. 5, broken lines represent the boundaries
between adjacent sections among the 12 projected sections 102-i
to 102.12.
In this embodiment, these 12 projected sections 102-i to
102-12 are determined on the basis of input image signal (s),
which will be described later. In this case, the projected
section to be projected by each projector is determined such
that the number of projectors assigned to a section containing a
large amount of information per unit area of the projection
image 102 is increased while the number of projectors assigned
to a section containing a small amount of information per unit
area of the projection image 102 is decreased.
FIG. 6 clearly shows a relationship between each of the
projectors 101_i to 101.12 and their corresponding projected
sections 102_i to 102_i2 of the projection image in which the
displayed projection image will be omitted from each of the
sections. It is to be noted that slightly overlapping parts
(blending regions) practically exist between the adjacent
projected sections that are projected by the adjacent projectors
but these overlapping parts will be omitted herein to simplify
the description here.
FIG. 7 shows a configuration of the multi-projection
system 100. This multi-projection system 100 contains an input
terminal 121, a projected-section-determining unit 122, an
image-signal-generating unit 123, and a projection-center and -
range control unit 124.
The input terminal 121 is used for allowing an image
signal Vin suitable for the projection image 102 to be input
(referred to FIG. 5) . Here, if the projectors 101-i to 101.12 are
constituted of display devices such as liquid crystal displays
(LCDs) and if each LCD includes Nh pixels (for example, 1024
pixels) per row and Nv pixels (for example, 768 pixels) per
column, then the input image signal Vin contains, for example,
pixel signals that are compatible with a matrix of pixels of NX
X Ny, where NX is larger than 4Nh in the horizontal direction
thereof, and Ny is larger than 3Nv in the vertical direction
thereof.
The projected-section-determining unit 122 contains a
dynamic-range-calculating portion 122a, a vertical delimitation
portion 122b, and a horizontal delimitation portion 122c (refer
to FIG. 7B) . The projected-section-determining unit 122
determines a section (a projected section) of the projection
image 102 to be projected onto the screen 110 by each of the
projectors 101-i to 101.12 on the basis of the image signal Vin
received through the input terminal 121 (refer to FIG. 4). How
to determine the projected section(s) by the projected-sectiondetermining
unit 122 will be described later.
The image-signal-generating unit 123 generates image
signals V-i to V.12 that correspond to the sections of the
projection image to be projected onto the screen 110 by the
respective projectors 101_i to 101.12, on the basis of the image
signal Vin received through the input terminal 121 and the
projected sections to be projected by the respective projectors
101-i to 101-12, which sections are determined by the projectedsection-
determining unit 122. The image signals V_i to V_i2
generated by the image-signal-generating unit 123 are
respectively supplied to the projectors 101-i to 101.12. The
projectors 101_i to 101-12 receive, respectively, the image
signals V_i to V_i2 thus supplied and project the projection image.
The following will describe a method that generates the
image signals by the image-signal-generating unit 123 with
reference to FIGS. 8A and 8B, where each "o" represents a pixel.
As shown in FIG. 8A, the numbers of pixels on the input
image signal Vin are obtained by multiplying NX in the
horizontal direction and Ny in the vertical direction, so there
are Ny (= vm + 1) horizontal lines from 0 to vm, and there are
NX (= hm + 1) vertical lines from 0 to hm.
Suppose that the above projected-section-determining
unit 122 determines vertical lines XI, X2 and X3 as the
horizontal section boundaries and horizontal lines Yl and Y2 as
the vertical section boundaries. In this moment, the projection
image 102 to be projected by the projectors 101-i to 101.12 is
divided into the projected sections 102.i to 102.12 thereof, as
shown in FIG. 8A, by the horizontal lines Yl and Y2 and the
vertical lines XI, X2 and X3.
In the image-signal-generating unit 123, the pixel
signals for, for example, for 1,024 x 768 pixels, constituting
each of the image signals V-i to V.12 to be respectively supplied
to the projectors lOl-i to 101.12 are produced by using any wellknown
interpolation process from the pixel signals in the input
image signal Vin for the pixels included in the projected
sections 102-i to 102-i2, respectively, as shown in FIG. 8B. For
example, as for the image signal V_i to be supplied to the
projector lOl-i, the pixel signals for 1,024 x 768 pixels are
produced from the pixel signals in the input image signal Vin
for the (XI + 1) x (Yl + 1) pixels included in the projected
section 102-1.
The projection-center and -range control unit 124
controls the projectors 101_i to 101-12 to adjust their projection
centers and projection ranges on the basis of the projected
sections 102_i to 102-i2 to be projected by the respective
projectors 101_i to 101-iz, which sections are determined by the
projected-section-determining unit 122. In this case, the
respective projectors 101-i to 101-i2 are controlled so that the
sections 102-i to 102.12 of the projection image 102 projected by
the projectors 101-i to 101.12 based on the above image signals V.
i to V_i2 can be respectively projected to their proper positions
(their projection centers with their projection ranges) on the
screen 110, which positions correspond to the projected sections
102-i to 102.12 of the projection image 102 to be projected by the
respective projectors 101_i to .101.12, described above.
FIG. 9 shows an example in which a projection center of
a projected section of the projection image is shifted in the
screen 110 from a position indicated in broken lines to a
position indicated in alternate long and short dash lines. In
addition, FIG. 10 shows an example in which a projection range
of a projected section of the projection image is changed from a
range indicated in broken lines to that indicated in alternate
long and short dash lines, or from a range indicated in broken
lines to that indicated in alternate long and two short dash
lines on the screen 110,
A lens-shift mechanism, which is provided to a well17
known projector, or a mechanism using a mirror shifts the
projection center thereof.
FIGS. 11A and 11B respectively show a displacement of
the projection center by the lens-shift mechanism. Shifting the
lens horizontally enables the projection center to be shifted in
the horizontal direction, as shown in FIG. 11A. Also, shifting
the lens vertically enables the projection center to be shifted
in the vertical direction, as shown in FIG. 11B. If such a
lens-shift mechanism is adopted, then the projection-center and
-range control unit 124 controls the projectors 101-i to 101-i2 to
adjust their lens-shift mechanism so that the lens is shifted
only by the distance that corresponds to the information of
projection-center shift, either horizontally or vertically, or
in both of the directions.
In addition, FIG. 12 shows a shift of a projection
center by a mechanism using a mirror. Rotating the mirror
horizontally or vertically enables the projection center to be
shifted in the horizontal or vertical direction, respectively.
If such a mechanism using a mirror is adopted, then the
projection-center and -range control unit 124 controls the
projectors lOl.i to 101-i2 to adjust their mechanism using the
mirror so that the mirror can be rotated, either horizontally or
vertically, or both horizontally and vertically, exactly by the
angular degree that corresponds to the information on
projection-center shift.
However, in the shift of the projection center by such a
mechanism using a mirror, if the image (projector image)
obtained by the projector is shown as a rectangle, then the
image (projected image) projected on the screen 110 can become
distorted and come to be trapezoidal as shown in FIG. 13A. In
this case, as shown in FIG. 13B, the image is processed for the
shift of the projection center such that the projector image is
made trapezoidal to offset the resultant distortion. As a
result, the projected sections of the projection image that are
projected onto the screen 110 respectively come to be
rectangular without any distortion.
The projection range can be changed by an aspect-ratio
change mechanism or the like using a zoom mechanism and a
cylindrical mirror or a cylindrical lens. The projection-center
and range control unit 124 controls the projectors 101-i to 101-i2
to adjust their zoom ratio and their aspect ratio in
correspondence to the information on the projection range. As
shown in FIG. 14, by adjusting the zoom ratio and the aspect
ratio in combination, any projection range can be achieved
optionally. In this moment, the size of the projection range is
determined by the zoom ratio while the shape of the projection
range is determined by the aspect ratio.
The aspect-ratio change mechanism uses, for example, a
cylindrical mirror. In this mechanism, the aspect ratio is
changed by changing the curvature of the cylindrical mirror.
Also, the aspect-ratio change mechanism may use, for example, a
plurality of cylindrical lenses for achieving aspect ratio
changes. In this mechanism, the aspect ratio is changed by
changing the cylindrical lens being used.
The following will describe methods that determine the
projected sections by the projected-section-determining unit 122.
Here, two methods, i.e., a first method and a second method,
will be described.
"Description of the first method"
At first, a local dynamic range (local DR) is calculated
for every pixel, by using the signal for a target pixel and the
signals for a predetermined number of pixels adjacent to the
target pixel on the basis of the input image signals Vin. For
example, as shown in FIG. 15, by using the signal (pixel signal)
for the target pixel PO and the signals (pixel signals) of eight
pixels PI to P8 adjacent to the target pixel PO, the difference
(MAX - MIN) between the minimum MIN and the maximum MAX is taken
as the local DR. In this sense, the projected-sectiondetermining
unit 122 contains the dynamic range calculation
portion 122a (see FIG. 7B).
The sum total S of the local DRs for all the pixels over
the whole image is then calculated. For example, for the image
shown in FIG. 16A, the sum total S is calculated as shown in FIG.
16B.
Next, vertical section boundaries are delimited by every
horizontal line where the accumulated sum of the local DRs comes
to be equal to a quotient of the sum total S of the local DRs
for all the pixels divided by the number of projectors per
column, 3 in this embodiment. Fqr example, for an image shown
in FIG. 17A, vertical section boundaries Yl, Y2 are delimited by
every horizontal line where the accumulated sum of the local DRs
becomes S/3 (see FIG. 17B) . In this sense, the projectedsection-
determining unit 122 contains the vertical delimitation
portion 122b (see FIG. 7B).
Further, horizontal section boundaries are delimited by
every vertical line where the accumulated sum of the local DRs
comes to be equal to a quotient of the sum total S of the local
DRs for all the pixels divided by the number of projectors per
.row, 4 in this embodiment. In this sense, the projected20
section-determining unit 122 contains the horizontal
delimitation portion 122c (see FIG. 7B).
As described above, the section boundaries in the
horizontal direction and in the vertical direction are delimited
for partitioning the projection image into the sections
(projected sections) 102-i to 102-i2 thereof to be projected onto
the screen 110 by the projectors 101.i to 101-i2, respectively.
In the sections 102. i to 102_i2 of the projection image 102 to be
projected by the projectors 101-i to 101-i2, respectively, which
sections are partitioned by the horizontal and vertical section
boundaries determined in the above-described way, the sum total
of the local DRs for all the sections is approximately equal.
In other words, the projected-section-determining unit 122
determines the horizontal or vertical section boundaries such
that the sum total of the local DRs for all sections 102-i to
102-12 of the projection image 102 to be projected by the
projectors 101.x to 101.i2 can be equal.
FIG. 18 shows a flowchart for showing operations of
determining the projected sections carried out according to the
above first method.
At first, the determination, operation starts at step ST1,
and the image signal Vin for one frame is input at step ST2.
Then, the whole image, i.e., all the pixels, is scanned to
calculate the sum total S of the local DRs for all the pixels at
step ST3.
Next, at step ST4, the mean value A is calculated by
dividing the sum total S by the number of projectors per column.
At step ST5, v, which represents the line number, of the
horizontal lines, is set to 0, and the accumulated sum is reset
to 0.
Next, at step ST6, it is determined whether or not the
line number v is greater than the maximum line number vm, i.e.,
v > vm. If not v > vm, then the operation proceeds to step ST7.
At the step ST7, the v-th horizontal line is scanned, and the
sum total of the local DRs for this particular line is
calculated. At step ST8, the sum total calculated at the step
ST7 is added to the accumulated sum.
Next, at step ST9, it is determined whether or not the
accumulated sum is smaller than the mean value A calculated at
step ST4. If the accumulated sum is smaller than the mean value
A, then the line number v is incremented by one at step ST10 and
the operation returns to the step ST6. By this returning, the
same operations are taken on the next horizontal line. In other
words, the sum total of the local DRs for this new line is
calculated, this sum total is added to the accumulated sum, and
whether this accumulated sum is smaller than the mean value A is
determined.
At the step ST9, if the accumulated sum is equal or
larger than the mean value A, then the operation proceeds to
step ST11. At the step ST11, the v-th horizontal line is
determined as a vertical section boundary. Then, at step ST12,
the accumulated sum is reset to 0, and at the step ST10, the
line number v is incremented by one. After that, the operation
returns to the step ST6. By this returning, the same operations
are taken for determining next vertical section boundary.
If v vm at step ST6, then this condition means that
all the vertical section boundaries have been determined, so the
operation proceeds to step ST13 where operations will be taken
for determining the horizontal section boundaries. At the step
ST13, the mean value B is calculated by dividing the sum total S
by the number of projectors per row. Then, at step ST14, h,
which represents the line number of the vertical lines, is set
to 0, and the accumulated sum is reset to 0.
Next, at step ST15, it is determined whether or not the
line number h is larger than the maximum line number hm, i.e., h
hm. If not h hm, then the operation proceeds to step ST16.
At the step ST16, the h-th vertical line is scanned, and the sum
total of the local DRs for this line is calculated. At step
ST17, the sum total calculated at the step ST16 is added to the
accumulated sum.
Next, at step ST18, it is a determined whether or not
the accumulated sum is smaller than the mean value B calculated
at the step ST13. If the accumulated sum is smaller than the
mean B, then, at step ST19, ,the line number h is incremented by
one. After that, the operation returns to the step ST15. By
this returning, the same operations are taken on a next vertical
line. In other words, the sum total of the local DRs for this
new line is calculated, this sum total is added to the
accumulated sum, and whether this accumulated sum is smaller
than the mean value B is determined.
At the step ST18, if the accumulated sum is equal or
larger than the mean value B, then the operation proceeds to
step ST20 where the h-th,vertical line is determined as a
horizontal section boundary. Then, at step ST21, the
accumulated sum is reset to 0, and at the step ST19, the line
number h is incremented by one. After that, the operation
returns to the step ST15. By this returning, the same
operations are taken for determining next horizontal section
boundary.
If h > hm at the step ST15, then this condition means
23
that all the horizontal section boundaries have been just
determined. Therefore, the operation proceeds to step ST22
where the operations terminate.
By executing the operations in the flowchart shown in
FIG. 18, the vertical and horizontal section boundaries can be
determined and thus, the sections 102.i to 102.i2 of the
projection image 102 to be projected by the respective
projectors 101_i to 101-i2 are determined as described above.
FIG. 19 shows information of the projection centers and
projection ranges for a case where a total of 12 projectors 101-
i to 101-12 are arranged in a matrix of four projectors per row
and three per column as shown in FIG. 4. In this case, the
information of the projection ranges by the projectors 101.i to
101-12 includes the horizontal section boundaries XI, X2 and X3
and the vertical section boundaries Yl and Y2. In addition, the
information of the projection centers by the projectors 101-i to
101-i2 includes Xl/2, (X2 - Xl)/2, (X3 - X2)/2 and (hm - X3)/2,
and Yl/2, (Y2 - Yl)/2 and (vm - Y2)/2.
"Description of the second method"
The following will describe a determination of the
horizontal section boundaries.
At first, input image signal Vin is taken as an original
image signal, and horizontal bandwidth-compression image signals
at a compression factor 1/b are generated on the basis of the
original image signal as shown in FIG. 20. Here, for the 1/b,
values are taken at 0.01 steps, for example, 1, 0.99, 0.98, ...,
or they can be at even smaller steps. For the generation of the
bandwidth-compression image signals at the 1/b, the horizontal
frequency bandwidth of the original image signal is limited by a
horizontal low pass filter (LPF) that limits the horizontal
bandwidth to FO/b where the horizontal frequency bandwidth of
the original image signals is taken as FO as shown in FIG. 21.
Next, the amount of image information is calculated for
each vertical strip, which abuts one another horizontally.
In other words, as shown in FIG. 22, the original image
signal (Vin) and the horizontal bandwidth-compression image
signals at the 1/b, respectively, are paired one with the other,
having, for example, eight-pixel width vertical strips, which
are numbered as 0 to imax. Then, the differences between the
pairs of pixels in each of the strips 0 to imax for the original
image signals (Vin) and the corresponding strip for the
horizontal bandwidth-compression image signals at the 1/b are
calculated. Then, the sum total of the absolute values of the
differences is calculated to generate a remainder 1(0, 1/b) to
I (imax, 1/b) for each of the strips 0 to imax. In this case,
the number of pixels included in each of the strips is 8 x vm,
so the remainder I(i, 1/b) is the sum total of the absolute
values of the differences for the 8 x vm pixels. In addition,
the remainder 1(0, 1/b) to I(imax, 1/b) for each of the strips 0
to imax is generated at each value of the 1/b.
Then, a relationship .between the remainder for each of
the strips 0 to imax and the 1/b is defined by using the
remainder 1(0, 1/b) to I(imax, 1/b) for each of the strips 0 to
imax, which is generated at each value of the 1/b, as shown in
FIGS. 23A to 23D. FIG. 24 shows these relationships together.
From the relationship between the 1/b and the remainder
for each of the strips 0 to imax generated at each value of the
1/b, the mean value of the 1/b is calculated for each of the
strips 0 to imax that correspond to the values of the respective
remainders, and a relationship is defined between the remainder
and the mean value of the compression factor 1/b as shown in FIG.
25. From this relationship between the remainder and the mean
value of the 1/b, an applied remainder is determined.
In this moment, if the input image signal Vin includes
pixel signals corresponding to the NX x Ny pixels as described
above, where NX is larger than 4Nh (Nh being the number of
pixels per row of a projector) in the horizontal direction, and
Ny is larger than 3Nv (Nv being the number of pixels per column
of the projector) in the vertical direction, as shown in FIG. 25,
the remainder RD that corresponds to the horizontal pixel number
compression ratio RT = 4Nh / NX is determined as the above
applied remainder.
From the relationship.between the remainder and the 1/b
for each of the strips 0 to imax shown in FIGS. 23A to 23D and
FIG. 24, the compression factor 1/b . (eO to eimax) that
corresponds to the applied remainder RD for each of the strips 0
to imax is calculated. Therefore, each compression factor eO to
eimax corresponds to the amount of image information for its
respective strips 0 to imax in the input image signal Vin. In
this sense, the projected-section-determining unit 122 contains
a first image-information amount calculation portion 122d (see
FIG. 27) that calculates the amount of image information for
each vertical strip, which abuts one another in the horizontal
direction.
In this case, the compression factor 1/b is made smaller
for a strip located in projection image in which a small amount
of information (flat places with few details, for example,
cloudless sky) is contained while the compression factor 1/b is
made larger for a strip located in projection image in which a
large amount of information (places with fine details, for
example, trees, buildings and structures) is contained.
Therefore, calculating the compression factor eO to eimax for
each of the vertical strips 0 to imax as described above is
equivalent to calculating the amount of image information for
each of the vertical strips.
Next, on the basis of the compression factors eO to
eimax of the vertical strips 0 to imax, a horizontal section
boundary is delimited by every vertical line where the
accumulated sum of the amounts of image information comes to
equal to a quotient of the sum total of the amounts of image
information for all the vertical strips divided by the number of
projectors per row, 4 in this embodiment. In this sense, the
projected-section-determining unit 122 contains the horizontal
delimitation portion 122b (see FIG. 27).
In this case, each of the strips 0 to imax with eightpixel
width, i.e., each part having eight pixels per row, as
shown in FIG. 26A is multiplied by its compression factor eO to
eimax, respectively, to achieve ah overall horizontal width NX'
= 8eO + 8el . . . + Seimax as shown in FIG. 26B. Then, this NX'
is divided by 4, which is the number of projectors per row in
this embodiment, as shown in FIG. 28A. In FIG. 28A, the broken
lines represent the boundaries of the sections of the projection
image, which are divided by 4.
In this context, it is assumed that the boundaries of
the sections exist in vertical strips nl, n2 and n3,
respectively, as shown in FIG. 28A. For each of the respective
vertical strips nl, n2 and n3, a determination is made as to how
the boundary divides internally the width of its corresponding
strip, and in correspondence to this internal ratio, a
determination is made at which position in the eight-pixel width
the boundary is located as shown in FIG. 28B. The vertical
lines that correspond to these positions, which are determined
in the above-mentioned way, are set as the horizontal section
boundaries XI, X2 and X3.
Although the above has been described on a process for
determining the horizontal section boundaries, a similar process
can be applied for determining the vertical section boundaries
Yl and Y2, whose detailed description will be omitted here. In
this sense, the projected-section-determining unit 122 contains
a second image-information amount calculation portion 122e (see
FIG. 27) that calculates the amounts of image information for
each horizontal strip aligned in the vertical direction, and the
vertical delimitation portion 122c (see FIG. 27) that delimits a
vertical section boundary by every horizontal line where the
accumulated sum of the amounts of image information equals the
quotient of the sum total of the amounts of image information
for all the horizontal strips divided by the number of
projectors per column, 3 in this embodiment.
As described above, the horizontal and vertical section
boundaries, which are used for partitioning the projection image
to be projected on the screen 110 by the projectors 101_i to 101-
12 into the sections 102_i to 102.12 (projected sections) , are
determined. In the projected sections 102-i to 102-i2, which are
partitioned by the horizontal and vertical section boundaries,
each section includes an approximately equal amount of image
information. In other words, the projected-section-determining
unit 122 determines the horizontal and vertical section
boundaries such that the same amount of image information is
distributed into each section, which is to be projected by its
respective projectors.
FIG. 29 shows a flowchart for showing operations of
determining the projected sections carried out according to the
above second method.
At first, at step ST31, the determination operations
start, and at step ST32, the image signal Vin for one frame is
input. At step ST33, a compression factor 1/b is selected. At
step ST34, horizontal bandwidth-compression image signals are
generated at the 1/b selected at the step ST33 (see FIG. 20 and
FIG. 21).
Next, at step ST35, the strip number i of the vertical
strips is set to 0, and the operation proceeds to step ST36. At
the step ST36, for the i-th vertical strip, the differences
between the pairs of pixels in the original image signal (Vin)
and in the horizontal bandwidth-compression image signals
generated at the step ST34 are calculated, and the sum total of
the absolute values of the differences is calculated to
calculate a remainder I (i, 1/b) (see FIG. 22).
Next, at step ST37, it is determined whether or not the
strip number i has reached its maximum strip number imax, i.e.,
i = imax. If not i = imax, then the strip number i is
incremented by one at step ST38. After that, the operation
returns to the step ST36. By this returning, the same
operations are taken for calculating a remainder I (i, 1/b) for
a next vertical strip.
At the step ST37, if i = imax, then this condition means
that remainders, I (0, 1/b) to I (imax, 1/b), have been
calculated for all the vertical strips O to i max, so the
operation proceeds to step ST39 where it is determined whether
or not the value selected for the 1/b at the step ST33 is the
last one. If it is not the last one, then the operation returns
to the step ST33 where the next value is selected for the 1/b.
Then, the same operations are taken for calculating the
remainder I (i, 1/b) for each of the strips at this 1/b.
If the 1/b has reached its last value at the step ST39,
then the operation proceeds to step ST40. At the step ST40, by
using the remainder I (0, 1/b) to I (imax, 1/b) for each of the
strips 0 to imax generated at each value of the 1/b, a
relationship between the remainder for each of the strips 0 to
imax and the 1/b is defined (see FIGS. 23A to 23D, and FIG. 24).
By using this relationship, the mean value of the 1/b for each
of the strips 0 to imax that correspond to each value of the
remainders is then calculated to determine the relationship
between the remainder and the mean value of the 1/b (see FIG.
Next, at step ST41, by using the relationship between
the remainder and the mean value of the 1/b, an applied
remainder RD is determined from the pixel number compression
ratio RT (= 4Nh / NX) (see FIG. 25), and from the relationship
between the remainder for each of the strips 0 to imax and the
1/b (see FIGS. 23A to 23D and FIG. 24), a compression factor 1/b
(eO to eimax) that corresponds to the applied remainder RD for
each of the strips 0 to imax is calculated.
Next, at step ST42, for each of the strips 0 to imax
with eight-pixel width, each eight-pixel width part is
multiplied by each of the compression factors eO to eimax to
determine the horizontal widths 8eO to Seimax of each of the
vertical strips (see FIGS. 26A and 26B).
Next, at step ST43, the horizontal boundaries are
determined. In other words, the total horizontal width NX'
(=8eO + 8el ...+8ei + ... + Seimax) is divided by 4, which are
the number of projectors per row, to create the four sections in
the projection image in the horizontal direction. Then, every
vertical line that is located in each of the vertical strips nl,
n2 and n3 where the boundaries for sections exist and
corresponds to a boundary location is determined as each of the
horizontal section boundaries XI, X2 and X3 (see FIGS. 28A and
28B and FIG. 19).
Now, the operation proceeds to step ST44 where the
determination of the vertical boundaries is initiated. The
operations to be taken at the step ST44 to step ST54 correspond
with those taken at the step ST33 to the step ST43, which are
described above, with only the difference of horizontal or
vertical.
At the step ST44, a compression factor 1/b is selected.
At the step ST45, vertical bandwidth-compression image signals
are generated in correspondence to the 1/b, which has been
selected at the step ST44 (see FIG. 20 and FIG. 21).
Next, at the step ST46, the strip number j for the
horizontal strips is set to 0, and the operation proceeds to the
step ST47. At the step ST47, for the j-th horizontal strip, the
differences between the pairs of pixels in the original image
signals (Vin) and in the vertical bandwidth-compression image
signals at the 1/b generated at the step ST45 are calculated,
and the sum total of the absolute values of the differences is
calculated to determine a remainder I (j, 1/b) (see FIG. 22).
Next, at the step ST48, it is determined whether or not
the strip number j has reached its maximum strip number jmax,
i.e., j = jmax. If not j = jmax, then the strip number j is
incremented by one at the step ST49. Thereafter, the operation
returns to the step ST47. By this returning, the same
operations are repeated for calculating a remainder I (j, 1/b)
for a next horizontal strip.
At the step ST48, if j = jmax, then this means that the
remainders I (0, 1/b) to I (jmax, 1/b) for all the vertical
strips 0 to jmax have been calculated, so the operation proceeds
to the step ST50 where it is determined whether or not the value
selected for the 1/b at the step ST44 is the last one. If not
the last value, then the operation returns to the step ST44
where the next value is selected for the 1/b. Then, the same
operations are repeated for calculating a remainder I (j, 1/b)
for each of the strips at this new 1/b.
If the last value for the 1/b at the step ST50, then the
operation proceeds to the step ST51. At the step ST51, by using
the remainder I (0, 1/b) to I (jmax, 1/b) for each of the strips
0 to jmax, which is generated at each value of the 1/b, a
relationship is defined between the remainder for each of the
strips 0 to jmax and the 1/b (see FIGS. 23A to 23D and FIG. 24) .
By using the relationship, the mean value of the 1/b for each of
the strips 0 to jmax in correspondence to each value of the
remainder is calculated. Then, a relationship is defined
between the remainder and the mean value of the 1/b (see FIG.
25) .
Next, at the step ST52, by using the relationship
between the remainder and the mean value of the 1/b, the applied
remainder RD is determined from the pixel number compression
ratio RT (= 3Nv / Ny) (see FIG. 25) . Furthermore, a compression
factor 1/b (eO to ejmax) that corresponds to the applied
remainder RD for each of the strips 0 to jmax is calculated from
the relationship between the remainder for each of the strips 0
to jmax and the 1/b (see FIG..23A to 23D and FIG. 24).
Next, at the step ST53, for each of the strips 0 to jmax
with eight-pixel width, each eight-pixel width part is
multiplied by the compression factors eO to ejmax to determine
the horizontal width 8eO to 8 ejmax of each vertical strip (see
FIGS. 26A and 26B).
Next, at the step ST54, the vertical boundaries are
determined. In other words, the overall vertical width Ny' (=
8eO + 8el + ... + 8ej + ... +8ejmax) is divided by 3, which are
the number of projectors per column, to create three sections in
the projection image in the vertical direction. Then, every
horizontal line that is located in each of the horizontal strips
nl and n2 where the boundaries for the sections exit and
corresponds to a boundary location is determined as each of the
vertical section boundaries Yl and Y2 (see FIGS. 28A and 28B and
FIG. 19).
At step ST55, the operations for determining the
sections of the projection image to be projected by the
respective projectors terminate,
Thus, the multi-projection system 100 as a preferred
embodiment determines the sections (projected sections) 102.3. to
102-i2 of the projection image 102 to be projected onto the
screen 110 by the projectors 101-i to 101.i2 on the basis of the
input image signal Vin, generates the image signals V_! to V.12
for the projectors 101-i to 101-12 on the basis of this projected
sections, and controls the projectors 101-i to 101-ia to adjust
their centers and ranges of the projections by the projectors.
Therefore, the number of projectors assigned to a
section of the projection image which contains the large amount
of information per unit area is increased while the number of
projectors assigned to a section of the projection image which
contains the small amount of information per unit area is
decreased. This enables high presentation resolution to be
realized without increasing the number of projectors used in the
system. From the same reason, in comparison with any related
system, the number of projectors for realizing the same
resolution can be decreased, thereby realizing cost reduction
therefor.
Although in the above embodiments, it has been described
that an apparatus and a method that present a projection image
are applicable to cases where a still picture is displayed on
the screen 110, this invention is not limited thereto. They can
be also applied to a case where a slowly changing image is
displayed on the screen 110. For displaying the slowly changing
image, the multi-projection system 100 shown in FIG. 7 may
determine the projected section for each projector by the
projected-section-determining unit 122 every predetermined
period of time and, on the basis of the result of this
determination, the image-signal-generating unit 123 and the
projection-center and -range control unit 124 operate.
Furthermore, in the above embodiments, the horizontal
boundaries and the vertical boundaries are determined
independently without considering the boundaries of each other,
so the horizontal and vertical section boundaries that define
the sections 102_i to 102.i2 of the projection image 102
projected by the projectors 101-i to 101-i2 are each continuous
as indicated by broken lines in FIG. 5.
However, for example, after the vertical section
boundaries are determined, the horizontal section boundaries may
be determined for each of the respective vertical sections.
In this moment, in the above-described first method, for
each of the respective vertical sections, preferably, horizontal
section boundaries are delimited by every vertical line where
the accumulated sum of the local DRs equals a quotient of the
sum total of the local DRs for the pixels in the respective
vertical sections divided by the number of projectors per row.
Also, in this moment, in the above-described second
method, for each of the respective vertical sections, preferably,
horizontal section boundaries are delimited by every vertical
line where the accumulated sum of the amounts of image
information equals a quotient of the amount of image information
for the respective vertical sections divided by the number of
projectors per row.
As a result, the horizontal section boundaries defining
the sections 102-i to 102-i2 of the projection image 102
projected by the projectors 10l-i to 101_i2 are continuous, but
the vertical section boundaries are not continuous and are
positioned different in the respective vertical sections as
indicated by broken lines in FIG. 30.
It is also possible that, for example, after the
horizontal section boundaries are determined, the vertical
section boundaries may be determined for each of the respective
horizontal sections.
In this moment, in the above-described first method, for
each of the respective horizontal sections, preferably, vertical
section boundaries are delimited by every horizontal line where
the accumulated sum of the local DRs equals a quotient of the
sum total of the local DRs for the pixels in the respective
horizontal sections divided by the number of projectors per
column.
Also, in this moment, in the above-described second
method, for each of the respective horizontal sections,
preferably, vertical section boundaries are delimited by every
horizontal line where the accumulated sum of the amounts of
image information equals a quotient of the amount of image
information in the respective horizontal sections divided by the
number of projectors per column.
In this moment, the vertical section boundaries defining
the sections 102_i to 102_i2 of the projection image 102
projected by the projectors 101-x to 101.12 are continuous, but
the horizontal section boundaries are not continuous and are
positioned different in the respective horizontal sections as
indicated by broken lines in FIG. 31.
Although, in the above embodiments, the multi-projection
system 100 containing a total of 12 projectors 101-i to 101-i2
arranged in a matrix of four per row and three per column has
been described, the number of projectors and their arrangement
are, of course, not limited to this.,
The apparatus that presents a projection image and the
like according to the present invention realizes high
presentation resolution without increasing the number of
projectors in the whole of the system, by determining as a
projected section the section of the projection image to be
projected on the screen by each of the projectors on the basis
of input image signals, by generating image signals for each
projector on the basis of.the above determined projected section,
and by controlling the projectors to adjust their centers and
ranges of the projections by the projectors. Thus, they are
suitably applied to, for example, a projection system and the
like for displaying, for example, a still picture or a slowly
changing image on a screen.
It should be understood by those skilled in the art that
various modifications, combinations, sub-combinations and
alternations may occur depending on design requirements and
other factors insofar as they are within the scope of the
appended claims or the equivalents thereof.

WHAT IS CLAIMED IS:
1. An apparatus that presents a projection image, the
apparatus comprising:
a screen;
plural projectors, each of which projects a section of
the projection image onto the screen to reproduce the projection
image;
a projected-section-determining unit that determines as
a projected section the section of the projection image based on
an input image signal, said section of the projection image
corresponding to a part of the screen onto which each of the
projectors projects the section of the projection image;
an image-signal-generating unit that generates an image
signal corresponding to the section of the projection image
which each of the projector projects onto the part of the screen,
based on the input image signal and the projected section which
has been determined by the projected-section-determining unit;
and
a projectors-controlling unit that controls the
projectors, respectively, to adjust any one of centers and
ranges of the projections by the projectors based on the
projected section which has been determined by the projectedsection-
determining unit.
2. The apparatus according to Claim 1 wherein the
projected-section-determining unit calculates a local dynamic
range for each pixel based on the input image signal by using a
signal relative to the pixel and a predetermined number of other
pixels adjacent to the pixel; and
wherein the projected-section-determining unit
determines as the projected section the section of the
projection image projected by each of the projectors based on
the local dynamic range for each pixel with sum total of the
local dynamic ranges for all the projected sections being equal.
3. The apparatus according to Claim 2 wherein plural
projectors are arranged in a matrix of rows and columns; and
wherein the projected-section-determining unit
comprises:
a dynamic-range-calculating portion that calculates the
local dynamic range for each pixel by using the pixel and a
predetermined number of other pixels adjacent to the pixel;
a vertical delimitation portion that delimits a vertical
section boundary by every horizontal line based on the local
dynamic range for each pixel which has been calculated by the
dynamic-range-calculating portion, said horizontal line being
determined by making an accumulated sum of the local dynamic
ranges equal to a quotient of the sum total of the local dynamic
ranges for all the pixels divided by the number of projectors
per the column; and
a horizontal delimitation portion that delimits a
horizontal section boundary by every vertical line based on the
local dynamic range for each pixel which has been calculated by
the dynamic-range-calculating portion, said vertical line being
determined by making the accumulated sum of the local dynamic
ranges equal to a quotient of the sum total of the local dynamic
ranges for all the pixels divided by the number of projectors
per the row.
4. The apparatus according to Claim 3 wherein the
horizontal delimitation portion sets all the pixels as pixels
belonging to each vertical section defined by the vertical
section boundaries delimited by the vertical delimitation
portion; and
wherein the horizontal delimitation portion delimits the
horizontal section boundaries for each vertical section.
5. The apparatus according to Claim 3 wherein the
vertical delimitation portion sets all the pixels as pixels
belonging to each horizontal section defined by the horizontal
section boundaries delimited by the horizontal delimitation
portion; and
wherein the vertical delimitation portion delimits the
vertical section boundaries for each horizontal section.
6. The apparatus according to Claim 1 wherein the
projected-section-determining unit calculates, based on the
input image signal, an amount of image information for each
vertical strip aligned in a horizontal direction and calculates
an amount of image information for each horizontal strip aligned
in a vertical direction; and .
wherein the projected-section-determining unit
determines, based on the amounts of image information for each
of the strips, as the projected section the section of the
projection image projected by each of the respective projectors
by distributing the equal amount of image information to each
section.
7. The apparatus according to Claim 6 wherein the
projectors are arranged in a matrix of rows and columns; and
wherein the projected-section-determining unit
comprises:
a first image-information amount calculation portion
that calculates an amount of image information for each vertical
strip aligned horizontally, by using plural bandwidthcompression
image signals which are bandwidth-limited
horizontally at plural levels and an original image signal
thereof;
a horizontal delimitation portion that delimits a
horizontal section boundary by every predetermined vertical line
based on the amount of image information for each vertical strip,
said amount of image information being calculated by the first
image-information amount calculation portion, said predetermined
vertical line being determined by making an accumulated sum of
the amounts of image information equal to a quotient of the sum
total of the amounts of image information for all the vertical
strips divided by the number of projectors per the row;
a second image-information amount calculation portion
that calculates an amount of image information for each
horizontal strip aligned vertically, by using plural bandwidthcompression
image signals which are bandwidth-limited vertically
at plural levels and the original image signal thereof; and
a vertical delimitation portion that delimits a vertical
section boundary by every predetermined horizontal line based on
the amount of image information for each horizontal strip, said
amount of image information being calculated by the second
image-information amount calculation portion, said predetermined
horizontal line being determined by making the accumulated sum
of the amounts of image information equal to a quotient of the
sum total of the amounts of image information for all the
horizontal strips divided by the number of projectors per the
column.
8. The apparatus according to Claim 7 wherein the
horizontal delimitation portion sets all the vertical strips as
vertical strips belonging to the respective vertical sections
defined by the vertical section boundaries delimited by the
vertical delimitation portion; and
wherein the horizontal delimitation portion delimits the
horizontal section boundaries for each vertical section.
9. The apparatus according to Claim 7 wherein the
vertical delimitation portion sets all the horizontal strips as
horizontal strips belonging to the respective horizontal
sections defined by the horizontal section boundaries delimited
by the horizontal delimitation portion; and
wherein the vertical delimitation portion delimits the
vertical section boundaries,,for each horizontal section.
10. A method that presents a projection image on a
screen by projecting separate sections of the projection image
on the screen from plural projectors, said method comprising the
steps of:
determining as a projected section each of the sections
of the projection image to be projected on the screen by each of
the projectors, based on an input image signal;
generating an image signal corresponding to each of the
section of the projection image to be projected on the screen by
each of the projectors, based on the input image signal and the
projected section which has been determined at the above
determining step; and
controlling the projectors to adjust any one of centers
and ranges of projections by the projectors based on the section
of the projection image determined at the above determining step.