Digital Camera Patent AbstractAn apparatus and a method are provided to allow a portion of a captured
image to be evaluated with a digital camera. A display device of
the digital camera can display the captured image. A specific area
of interest of the captured image can be defined on the display
device by zooming and panning or by defining a window over the captured
image, and a histogram derived from only that area of interest can
be displayed. The histogram can represent different types of information
about the pixels of the captured image within the area of interest
such as the levels of individual colors and luminance.
Digital Camera Patent ClaimsWhat is claimed is:
1. A method for providing a zoomed histogram display on a digital
camera, comprising: reading a captured image from a memory device
and displaying it as a digital image on a display device of the
digital camera including mapping a first number of stored pixels
of the captured image to displayed pixels of the display device;
zooming the digital image until only an area of interest of the
digital image is displayed; deriving a histogram based on the area
of interest; and displaying the histogram.
2. The method of claim 1 wherein zooming the digital image includes
mapping a second number of stored pixels of the captured image to
the displayed pixels, the second number of stored pixels being less
than the first number of stored pixels.
3. The method of claim 2 where each stored pixel of the second
number of stored pixels includes a value within a range for an image
value.
4. The method of claim 3 wherein deriving the histogram includes
dividing the range into a number of bins so that each bin represents
a part of the range, and counting for each bin the stored pixels
of the second number of stored pixels that have values within the
part of the range represented by that bin.
5. The method of claim 2 wherein the image value represents a level
of a color channel.
6. The method of claim 2 wherein each stored pixel of the second
number of stored pixels includes a value within a range for each
of three color channels.
7. The method of claim 6 wherein deriving the histogram includes
dividing the range for each of the three color channels into a number
of bins so that each bin represents a part of that range, and counting
for each bin of each color channel the stored pixels of the second
number of stored pixels that have values within the part of the
range represented by that bin.
8. The method of claim 6 wherein deriving the histogram includes
calculating for each stored pixel of the second number of stored
pixels a weighted combination of the values of the three color channels
to determine a derived value within a derived range, dividing the
derived range into a number of bins so that each bin represents
a part of the derived range, and counting for each bin the stored
pixels of the second number of stored pixels that have derived values
within the part of the derived range represented by that bin.
9. The method of claim 8 wherein the derived value is a luminance
value.
10. A method for providing a zoomed histogram display on a display
device, comprising: reading a captured image from a memory device
and displaying it as a digital image on the display device including
mapping a first number of stored pixels of the captured image to
displayed pixels of the display device; zooming the digital image
until only an area of interest of the digital image is displayed;
deriving a histogram based on the area of interest; and displaying
the histogram.
11. The method of claim 10 wherein zooming the digital image includes
mapping a second number of stored pixels of the captured image to
the displayed pixels, the second number of stored pixels being less
than the first number of stored pixels.
12. The method of claim 10 where each stored pixel of the second
number of stored pixels includes a value within a range for an image
value.
13. The method of claim 12 wherein deriving the histogram includes
dividing the range into a number of bins so that each bin represents
a part of the range, and counting for each bin the stored pixels
of the second number of stored pixels that have values within the
part of the range represented by that bin.
14. The method of claim 10 wherein the image value represents a
level of a color channel.
15. The method of claim 10 wherein each stored pixel of the second
number of stored pixels includes a value within a range for each
of three color channels.
16. The method of claim 15 wherein deriving the histogram includes
dividing the range for each of the three color channels into a number
of bins so that each bin represents a part of that range, and counting
for each bin of each color channel the stored pixels of the second
number of stored pixels that have values within the part of the
range represented by that bin.
17. The method of claim 15 wherein deriving the histogram includes
calculating for each stored pixel of the second number of stored
pixels a weighted combination of the values of the three color channels
to determine a derived value within a derived range, dividing the
derived range into a number of bins so that each bin represents
a part of the derived range, and counting for each bin the stored
pixels of the second number of stored pixels that have derived values
within the part of the derived range represented by that bin.
18. The method of claim 17 wherein the derived value is a luminance
value. Digital Camera Patent DescriptionBACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of photography
and more specifically to a method and apparatus for analyzing captured
digital images.
2. Description of the Prior Art
FIG. 1 provides a cross-section of a digital Single Lens Reflex
(SLR) camera 100 of the prior art. The digital SLR camera 100 includes
a housing 102 and a lens system 104 that in most designs is removable.
The lens system 104 includes focusing optics 106 that direct incoming
light along an optical axis 108. A sensor 110 intersects, and is
typically centered on, the optical axis 108 opposite the lens system
104 along a focal plane thereof.
The sensor 110 typically consists of an array of photosensitive
pixel sensors that are each capable of converting incident light
into an electric signal. Image capturing electronics create a digital
image by digitizing the electric signals from each of the pixel
sensors of the sensor 110, processing the digitized data, and storing
the resulting processed data to a memory device (not shown) such
as a Random Access Memory (RAM) or a magnetic disk. The digital
image is typically stored as an array of pixels, where each pixel
includes color and brightness information for a particular location
in the digital image.
Commonly, camera 100 includes a display device 112, such as a liquid
crystal display (LCD), to allow a user 114 to review captured digital
images. Processing electronics 116 are provided to process captured
digital images in order to generate the displayed images shown on
the display device 112. Although the captured digital images are
typically of a high resolution, the displayed images tend to be
of a lower resolution. The difference in resolution can be caused
by several factors. For example, the number of pixels in the display
device 112 devoted to displaying an image is typically far fewer
than the number of pixels of the full digital image. Additionally,
a pixel in a display device 112 is typically unable to display as
many gradations in brightness as can be represented by a pixel in
the captured image. Accordingly, it can be difficult for a user
114 to judge the quality of a captured digital image from a displayed
image as viewed on the display device 112.
Accordingly, what is needed is an apparatus and method that will
allow a user of a digital camera to evaluate a captured digital
image to determine whether the digital image is satisfactory or
whether the digital image should be retaken, for example, with a
different exposure setting.
SUMMARY
The present invention provides both an apparatus and a method for
allowing a user of a digital camera to evaluate portions of a captured
image to determine, for example, whether to retake the image with
a different exposure setting. The apparatus of the invention is
a digital camera provided with a display device, a user interface,
and processing electronics. The display device is configured to
display a captured image, and the user interface allows the user
to select a reduced portion of the captured image, for example,
with controls that enable the captured image to be zoomed and panned
on the display device. The processing electronics are configured
to derive a histogram of the reduced portion, and can also be configured
to provide the histogram to the display device.
The histogram is a graphical representation of a distribution of
values for those pixels of the captured image that are within the
reduced portion. The values are discrete numbers within fixed ranges
for either stored or derived image values. A stored image value,
such as a level of a color channel, is one that is stored for each
pixel of the stored digital image. A derived image value is not
stored for each pixel but is instead calculated from one or more
stored image values. One such derived image value is luminance which
is a weighted combination of color channels. In some embodiments
the histogram includes values from more than one image value, for
example, a histogram with a line for each of three color channels.
The invention also includes a method for providing a histogram
display on a digital camera. The method includes displaying a captured
image as a displayed image on a display device of the digital camera,
where the captured image includes a first number of stored pixels.
The method also includes selecting a reduced portion of the captured
image, where the reduced portion includes a second number of stored
pixels less than the first number of stored pixels. Additionally,
the method includes deriving a histogram from the second number
of stored pixels and displaying the histogram.
Selecting the reduced portion can include, for example, zooming
the displayed image on the display device or defining a reduced
window on the displayed image. In those embodiments where selecting
the reduced portion includes defining a reduced window on the displayed
image, the reduced window can be rectangular, circular, or have
a shape defined by the user. In some embodiments more than one reduced
window can be defined on the displayed image to select the reduced
portion. Displaying the histogram can include showing the histogram
adjacent to the displayed image, overlaid over the displayed image,
or in place of the displayed image.
The invention also includes a method for providing a zoomed histogram
display on a digital camera. This method includes displaying a digital
image on a display device of the digital camera, and zooming the
digital image until only an area of interest of the digital image
is displayed. The method also includes deriving a histogram based
on the area of interest and displaying the histogram. Displaying
the digital image can include reading a stored digital image from
a memory device. The stored digital image can include a first number
of stored pixels that are mapped to displayed pixels of the display
device. Zooming the digital image includes mapping a second number
of stored pixels of the stored digital image to the displayed pixels,
where the second number of stored pixels is less than the first
number of stored pixels.
Each stored pixel of the second number of stored pixels includes
a value within a range for a stored image value. The histogram can
be derived by dividing the range into a number of bins and counting
stored pixels for each bin. Here, each bin represents a part of
the range, so the stored pixels counted for each bin are those having
values for the stored image value within the part of the range represented
by that bin. In those embodiments where each stored pixel includes
more than one stored image value, such as one image value for each
of three color channels, the range for each color channel can be
divided into a number of bins and the stored pixels of the second
number of stored pixels can be counted for each bin of each range.
In some embodiments deriving the histogram can include calculating
a luminance value for each stored pixel of the second number of
stored pixels by calculating a weighted combination of the values
of the three color channels. For each stored pixel this calculation
will determine a derived value within a derived range. The derived
range can be divided into a number of bins as described above, and
the derived values for the stored pixels in the second number of
pixels can be counted for each of these bins.
The invention further includes a method for evaluating a captured
image stored on a digital camera. This method includes displaying
the captured image on a display device of the digital camera, and
selecting an area of interest from the captured image, where the
area of interest is less than an entire area of the captured image.
The method also includes displaying a histogram derived from the
area of interest and evaluating the histogram. To better evaluate
the histogram the histogram can be rescaled on the display device
to show only a segment thereof. In particular, this can allow the
user to view only a segment of a range of an image value, such as
the ends of the range that show the numbers of pixels that are either
under exposed or over exposed for the particular image value. Based
on the evaluation of the histogram, a user can determine whether
the captured image is acceptable. If the captured image is not acceptable,
the user in some cases can attempt to acquire a more acceptable
one.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a cross-sectional view of a digital camera according
to the prior art;
FIG. 2 is a view of a display portion of a digital camera according
to an embodiment of the invention;
FIG. 3 is a view of a display portion of a digital camera according
to another embodiment of the invention;
FIG. 4 is a view of a display portion of a digital camera according
to another embodiment of the invention; and
FIG. 5 is a schematic diagram of components of a digital camera
according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides an apparatus and a method for allowing
a user of a digital camera to evaluate parts of a captured image.
The ability to evaluate parts of the captured image can allow the
user to determine, for example, whether to continue to save the
captured image or whether to retake it with a different exposure
time. More specifically, the invention provides a digital camera
with a display device, such as an LCD, that can display the captured
image as a displayed image and display a histogram derived from
a reduced portion of the captured image. The invention allows the
user to define a specific area of interest of the displayed image
through the use of a user interface. Processing electronics within
the digital camera derive the histogram from only those pixels in
the reduced portion of the captured image that correspond to the
area of interest in the displayed image. The processing electronics
can then display the histogram on the display device. The histogram
can represent different types of information about the area of interest
such as the levels of individual color channels or of the luminance.
FIG. 2 is a view of a display portion of a digital camera 200 of
the invention, where the display portion is preferably opposite
a front side that can include a lens system. The digital camera
200 includes a display device 202 and a user interface 204. Although
shown in FIG. 2 as adjacent one another in a display portion of
the digital camera 200, it will be appreciated that the display
device 202 and the user interface 204 can be located separately
and need not be opposite the lens system. The user interface 204
includes controls, such as buttons 206, that allow the display device
202 to be used in various ways. For example, in some embodiments
the user interface 204 can be used to toggle the digital camera
200 between a viewfinder mode and an image review mode. In the viewfinder
mode the display device 202 is configured to show a real-time image
of any illumination being received through the lens system. In the
image review mode the display device 202 is configured to display
captured images such as those stored in a memory device of the digital
camera 200. The memory device can be non-volatile and either internal
to the digital camera 200 or externally attached. In some embodiments
the image review mode can also be used to review a captured image
stored in a volatile memory device such as a buffer used to temporarily
cache the captured image.
When the digital camera 200 is in the image review mode, the user
interface 204 allows the user to perform various activities interactively
with the display device 202. These activities include displaying
menus on the display device 202, navigating through the menus, and
selecting options presented by the menus. Activities can also include
viewing a plurality of captured images as side-by-side or tiled
thumbnail images in a small image format and selecting a captured
image to view in a larger image format on the display device 202,
such as displayed image 208. Another activity available through
the user interface 204 is to select and delete captured images that
are not desired to be retained.
The option to view the displayed image 208 in a larger image format
allows the user to better evaluate the captured image than when
viewed as a thumbnail. In one larger image format the displayed
image 208 fills the entire area of the display device 202. As shown
in FIG. 2, other larger formats display the displayed image 208
in a window that is larger than the size of a thumbnail image yet
smaller than the entire area of the display device 202. Some embodiments
allow the user to toggle between several image formats through the
use of the user interface 204.
Despite the availability of larger image formats, it will be appreciated
that sometimes it can be difficult for a user to judge the quality
of a captured image from the displayed image 208 due to resolution
limitations of the display device 202, as discussed above in the
Description of the Prior Art. For example, if the displayed image
208 in FIG. 2 corresponds to a captured image that was acquired
with an autoexposure mechanism that looked to the center of the
image to set the exposure time, the exposure time would be lengthy
since the center of the captured image is predominantly black. Thus,
other areas of the captured image, such as the face, may be badly
overexposed. Yet, even when viewed in a larger image format on the
display device 202, the overexposure might not be apparent to the
user. Accordingly, it is often useful to have other means for evaluating
the captured image.
When the displayed image 208 is displayed in a window, as shown
in FIG. 2, the display device 202 can also be used to display related
image information adjacent to or within the window. Image information
can include, for instance, identifying indicia, exposure time, and
resolution of the captured image. Image information can also include
statistical information derived from the captured image such as
a histogram 210. A histogram 210 is a graphical representation of
a distribution of image values for pixels of the captured image.
The image values can represent a level of a grayscale in black and
white photography, while in color photography image values can be,
for example, a level of a color channel or of the luminance of the
several color channels. Luminance is a weighted combination of color
channels meant to approximate brightness, the subjective attribute
of light as perceived by the human eye. Accordingly, the color channels
are weighted to account for the differences in the eye's sensitivity
to light of different colors and intensities.
More specifically, an image value for any particular pixel is a
discrete value within some fixed range. The range is typically a
power of two, such as 256 or 512, though the range can be any number.
Accordingly, a histogram 210 is typically arranged such that a X-axis
represents the range of an image value while the Y-axis represents
numbers of pixels. As an example, in a well exposed captured image
there will be some pixels with a luminance near the bottom of a
range and some pixels with a luminance near the top of the range,
while the majority of the pixels will have luminances distributed
throughout the middle of the range. The histogram 210 in FIG. 2
illustrates such a distribution.
According to the present invention, as shown in FIG. 3, a histogram
212 is derived from a reduced portion of the captured image that
the user can select with the user interface 204. One method for
selecting the reduced portion is to pan and zoom the displayed image
208 until only an area of interest 214 of the displayed image 208
is displayed. Panning and zooming can be achieved, for example,
with a zoom rocker 216 to zoom and a joystick 218 to pan.
It should be noted at this point that a captured image, as stored,
is made up of a first number of pixels that is often on the order
of millions of pixels ("megapixels") whereas the number
of pixels in the entire area of the display device 202 is typically
far fewer. The pixels of the captured image and of the displayed
image 208 will be referred to as stored pixels and displayed pixels,
respectively. Accordingly, to display the captured image on the
display device 202 requires mapping many stored pixels to each displayed
pixel. The mapping can be achieved, for example, by taking an average
of image values of many stored pixels to create a set of image values
for the displayed pixel.
In view of the above, it will be appreciated that when the displayed
image 208 is zoomed to the area of interest 214 those stored pixels
outside of the area of interest 214 are no longer mapped to displayed
pixels, and also that the number of stored pixels mapped to each
displayed pixel decreases. Zooming is therefore sometimes thought
of as changing a magnification of the displayed image 208 since
it has the effect of making features in the displayed image 208
appear larger on the display device 202. For example, the features
in the area of interest 214 appear several times larger in FIG.
3 than they do in the displayed image 208 in FIG. 2.
By contrast, panning does not change the number of stored pixels
mapped to each displayed pixel. Instead, panning changes which stored
pixels are mapped to each displayed pixel. Accordingly, panning
has the effect of changing which stored pixels are mapped to the
area of interest 214 and which are excluded. Panning therefore produces
the visual effect of moving through or across the displayed image
208 at the particular magnification already set by the zoom.
According to the invention, histogram 212 is derived from the stored
pixels within a reduced portion of the captured image, such as the
stored pixels that are mapped to the displayed pixels of the area
of interest 214, as will be described in greater detail with respect
to FIG. 5. It will be appreciated that in addition to panning and
zooming there are other methods for a user to select the reduced
portion of the captured image. For example, in some embodiments
the user interface 204 is used to define a reduced window 220 on
the displayed image 208 as shown in FIG. 4. In some of these embodiments
the zoom rocker 216 can be used in conjunction with the joystick
218 to select a size for the reduced window 220 and to position
the reduced window 220 within the displayed image 208 over some
area of interest. In these embodiments the histogram 212 is derived
from the stored pixels that map to the displayed pixels within the
reduced window 220.
In some embodiments, histogram 212 is derived from values assigned
to the displayed pixels within the reduced window 220 or the area
of interest 214 (FIG. 3). The values assigned to the displayed pixels
are derived from the image values of the stored pixels that map
to the displayed pixels, for example, by averaging over small groups
of the stored pixels. Thus, in these embodiments the histogram 212
represents a distribution of values derived from the image values
of the stored pixels rather than a distribution of the image values
of the stored pixels themselves.
The reduced window 220 in FIG. 4 is not limited to rectangular
shapes. In some embodiments the reduced window 220 can be circular
and in some of these embodiments the user interface 204 can be used
to select a center point and a radius of the circular reduced window
220. In still other embodiments the user can employ the user interface
204 to draw a free-hand reduced window 220 on the displayed image
208. In yet other embodiments more than one reduced window 220 can
be defined over the displayed image 208. In these embodiments the
several reduced windows 220 are considered together to determine
the histogram 212. Further, it will be understood that the zoom
rocker 216 and the joystick 218 are exemplary controls for the user
interface 204, but that the invention is not limited to these particular
control devices. In some embodiments, for example, the display device
202 is touch sensitive and the user interface 204 allows the user
to define the reduced window 220 on the displayed image 208 by touching
the screen, for example, with a stylus or a finger.
FIG. 5 is a schematic diagram showing processing electronics 222
configured to respond to commands from the user interface 204 in
order to create a display on the display device 202 such as from
data stored in a memory device 224. The memory device 224 is configured
to store a captured image 225 including a first number of the stored
pixels 226. As noted above, the user interface 204 is configured
to allow the user to select an area of interest 214 on the display
device 202. The processing electronics 222 are configured to identify
a second number of the stored pixels 226 in a reduced portion 228
of the captured image 225 that are mapped to the displayed pixels
within the area of interest 214.
The processing electronics 222 are also configured to derive the
histogram 212 from the second number of stored pixels 226 in the
reduced portion 228 and to display the histogram 212 on the display
device 202. The histogram 212 can represent stored image values,
such as the levels of individual color channels. In some embodiments
the individual color channels are the primary colors typically used
in imaging devices, namely red, green, and blue, though any combination
of colors can be used. The histogram 212 can also represent derived
image values, such as luminance which is calculated from the stored
image values. Another derived image value can be a value for a displayed
pixel within the area of interest 214, where the value is derived
from one or more stored image values, as described above.
As noted above, image value information is digitized into discrete
values within a fixed range so that, for example, a stored pixel
226 will include one of 256 possible values for the red color channel,
another of 256 possible values for the blue color channel, and so
forth. In some embodiments the processing electronics 222 derive
the histogram 212 by first dividing the range for a particular image
value into a number of bins, where each bin represents a part of
the range. In some embodiments each of the discrete values in the
range is assigned a separate bin, while in other embodiments two
or more consecutive values are assigned to each bin. Next, the processing
electronics 222 counts the number of stored pixels 226 within the
part of the range assigned to each bin. Accordingly, a number of
stored pixels 226 are determined for each bin, and a sum of the
number of stored pixels in all of the bins equals the second number
of stored pixels 226 in the reduced portion 228.
It will be appreciated that the processing electronics 222 can
count the number of stored pixels 226 for each bin within a range
for more than one image value so that more than one image value
is represented in the histogram 212. In some embodiments three image
values, namely each of the three primary color channels, are each
represented as a separate line in the histogram 212 such that the
line representing the red color channel is itself red in the histogram
212, and so forth. In some embodiments the user interface 204 can
be used to select which image values are shown in the histogram
212 so that the user can, for example, toggle between luminance
and any one of the individual color channels, or any combination
of image values.
It will also be appreciated that the histogram 212 can be scaled
in any of a number of different ways. For example, the histogram
212 can be autoscaled so that a range for the Y-axis of histogram
212 has a maximum equal to the number of stored pixels 226 in a
most populated bin and a minimum equal to the number of stored pixels
226 in a least populated bin. Alternately, the maximum and minimum
for the Y-axis range can be fixed values. In some embodiments those
fixed values are equal to the number of stored pixels 226 in the
most and least populated bins when the entire captured image 208
is considered in place of the reduced portion 228. In some embodiments,
the Y-axis maps a nonlinear function of the number of counted pixels,
for example a cube-root or an approximately logarithmic function.
Here, too, the user interface 204 in some embodiments can allow
the user to switch between different scales for the Y-axis. Likewise,
the X-axis of the histogram 212 can also be scaled in different
ways. For example, the X-axis can be scaled to the entire range
for an image value, or a user selected segment of the range to allow
the user to examine, for example, just an end of the range.
Further, image values can be represented in different ways within
the histogram 212. One way to represent an image value is with a
solid line as shown in FIGS. 2 5. Another way to represent an image
value is to additionally shade the area beneath the line. In some
embodiments the way image values are represented depends on the
number of image values that are being displayed. Other graphical
representations, such as bar graphs, can also be implemented.
Additionally, the display of the histogram 212 can be implemented
in numerous ways. As shown in FIGS. 3 and 5 the histogram 212 can
be displayed on the display device 202 adjacent to the area of interest
214. Similarly, as shown in FIG. 4, the histogram 212 can be displayed
on the display device 202 adjacent to the displayed image 208 where
the displayed image 208 includes the user selected reduced window
220 around the area of interest 214. In other embodiments the histogram
212 is superimposed over the area of interest 214, where the area
of interest 214 either fills the entire area of the display device
202 or a window of the display device 202 such as the window illustrated
in FIGS. 3 and 5. In some embodiments in which the histogram 212
and the area of interest 214 are both displayed simultaneously on
the display device 202, as the area of interest 214 is changed the
histogram 212 is refreshed. Thus, as the user zooms and pans with
the user interface 204, for example, the processing electronics
222 continuously update the histogram 212.
In still other embodiments the user can employ the user interface
204 to toggle between viewing either the histogram 212 or the area
of interest 214 on the display device 202. In yet other embodiments
the user can toggle between a first mode in which the stored digital
image 208 fills the entire area of the display device 202 and a
second mode in which the histogram 212 is displayed on the display
device 202 adjacent to the area of interest 214. In some of these
embodiments the area of interest 214 can be selected in the first
mode, for example, by panning and zooming with the user interface
204. In still other embodiments various image information can be
displayed adjacent to both the histogram 212 and the area of interest
214 in the second mode. Other modes with other permutations are
also envisioned, such as a mode in which the image information and
the histogram 212 are displayed without the area of interest 214,
and a mode in which the area of interest 214 and the image information
are displayed without the histogram 212.
Further embodiments of the invention allow a user to prospectively
evaluate how an image is likely to turn out if acquired. These embodiments
can be useful when the digital camera is in the viewfinder mode,
for example. In some of these embodiments the sensor 110 (FIG. 1)
is repeatedly scanned to create a periodically refreshed real-time
image on the display device 202. Each scan of the sensor 110 can
produce a frame of the real-time image. Each frame can be stored
as a number of pixels in a memory device 224, such as a volatile
frame buffer. Accordingly, each frame can serve as a captured image
225. A reduced portion 228 can be selected, for example, by zooming
and panning to define an area of interest 214 or by drawing a reduced
window 220 (FIG. 4). A histogram 212 can then be derived from the
reduced portion 228. In some embodiments, each time the frame buffer
is refreshed with a new frame, the histogram 212 is derived again
from the reduced portion.
In the foregoing specification, the invention is described with
reference to specific embodiments thereof, but those skilled in
the art will recognize that the invention is not limited thereto.
Various features and aspects of the above-described invention may
be used individually or jointly. Further, the invention can be utilized
in any number of environments and applications beyond those described
herein without departing from the broader spirit and scope of the
specification. The specification and drawings are, accordingly,
to be regarded as illustrative rather than restrictive. |