Title: Electronic device compass operable irrespective of localized magnetic field
Abstract: An electronic device (10). The device comprises means (14) for displaying a compass directional bearing. The device also comprises means (18, 26, CAM) for determining the compass directional bearing unresponsive to a local magnetic field in which the electronic device is located, wherein the means for determining comprises image capturing circuitry.
Patent Number: 7,024,782 Issued on 04/11/2006 to Bork
| Inventors:
|
Bork; Stephan M. (Dallas, TX)
|
| Assignee:
|
Texas Instruments Incorporated (Dallas, TX)
|
| Appl. No.:
|
975139 |
| Filed:
|
October 28, 2004 |
| Current U.S. Class: |
33/355R; 702/150 |
| Current Intern'l Class: |
G01C 17/00 (20060101) |
| Field of Search: |
33/355 R,361,300,301
701/207-224
702/92,94,150
|
References Cited [Referenced By]
U.S. Patent Documents
| 5075864 | Dec., 1991 | Sakai.
| |
| 5768151 | Jun., 1998 | Lowy et al.
| |
| 5890092 | Mar., 1999 | Kato et al.
| |
| 6259990 | Jul., 2001 | Shojima et al.
| |
| 6930715 | Aug., 2005 | Mower.
| |
| 2002/0152050 | Oct., 2002 | Vann.
| |
| 2004/0176925 | Sep., 2004 | Satoh et al.
| |
| 2005/0184866 | Aug., 2005 | Silver et al.
| |
Primary Examiner: Bennett; G. Bradley
Attorney, Agent or Firm: Neerings; Ronald O., Brady, III; Wade James, Telecky, Jr.; Frederick J.
Goverment Interests
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
The present embodiments relate to electronic devices and are more particularly
directed to a compass for use in an electronic device, where the compass is operable
irrespective of the magnetic field in which the device is located.
Electronic devices are extremely prevalent and beneficial in today's society
and are constantly being improved due to consumer and user demand. One technological
example has been the portable or cellular telephone marketplace, which has seen
great advances in the last many years. These devices have evolved beyond provision
of voice services alone and are now accommodating greater amounts of data and are
providing various additional features, more advanced operating systems, and additional
programming. For example, so-called "smart phones" are envisioned as having a large
impact on upcoming generations of cellular phones. Also, various personal digital
assistants ("PDAs") are still succeeding in the marketplace and may do so for the
foreseeable future. Further, the functionality of cellular phones and PDAs are
now beginning to overlap with the possibility of a greater combination of the functionality
of these devices into a single unit in the future.
With the advancement of the devices introduced above, various newer features
are now being developed and implemented, as are known in the art. One feature that
is now found in some cellular phones is a magnetically-responsive compass. As a
compass, the device serves in the ordinary sense of such a component, that is,
to present to the phone user an indication of the directionality of the physical
orientation of the phone. In the present art, such a compass is constructed in
part using an element (or elements) that is sensitive to the local magnetic field,
that is, the field at the location of the phone. For example, one implementation
uses a two-dimensional magneto-resistive measurement bridge, which changes its
resistance in response to a change in the orientation of the bridge as influenced
by the local magnetic field. Circuitry, such as a differential amplifier and an
analog-to-digital converter, sense the voltage output of the bridge and translate
that output into a corresponding directionality indication.
While the preceding approach to a cellular phone compass may prove a desirable
feature in some instances, the present inventor has observed that it has certain
drawbacks. For example, the magneto-resistive measurement bridge extends only in
two dimensions, presumably to coincide with the two-dimensional nature of the circuit
board(s) inside the phone. As such, the bridge might produce erroneous and indeed
erratic indications if the phone is positioned in a manner that is not parallel
to the earth's surface. As another example, because the bridge is responsive to
local magnetic field, then the resulting output will produce an erroneous indication
of direction when the phone is in a location that is subject to aberrations in
the earth's magnetic filed or nearby metal objects that might distort the earth's
magnetic field at the then-existing location of the phone. As still another example,
both device cost and circuit board space are increased with the inclusion of the
bridge circuit and its associated circuitry.
As a result of the preceding, there arises a need to address the drawbacks of
the prior art as is achieved by the preferred embodiments described below.
BRIEF SUMMARY OF THE INVENTION
In one preferred embodiment, there is an electronic device. The device comprises
means for displaying a compass directional bearing. The device also comprises means
for determining the compass directional bearing unresponsive to a local magnetic
field in which the electronic device is located, wherein the means for determining
comprises image capturing circuitry.
Other aspects are also disclosed and claimed.
Claims
The invention claimed is:
1. An electronic device, comprising:
means for displaying a compass directional bearing; and
means for determining the compass directional bearing unresponsive to a local
magnetic field in which the electronic device is located, wherein the means for
determining comprises image capturing circuitry.
2. The device of claim 1 wherein the means for determining comprises:
a computer program; and
a processor operable to process the computer program at least in part to determine
the compass directional bearing.
3. The device of claim 2 and further comprising SPS circuitry for determining
location fixes of the electronic device, wherein the processor is operable to process
the computer program to determine the compass directional bearing in response to
the location fixes.
4. The device of claim 2, wherein the processor is operable to process the computer
program to determine the compass directional bearing in response to images captured
by the image capturing circuitry.
5. The device of claim 4 wherein the image capturing circuitry comprises still
image capturing circuitry.
6. The device of claim 4 wherein the image capturing circuitry comprises video
image capturing circuitry.
7. The device of claim 4 wherein the processor is operable to process the computer
program to determine the compass directional bearing in response to either extrapolation
or interpolation of the images.
8. The device of claim 2 and further comprising:
SPS circuitry for determining location fixes of the electronic device; and
image capturing circuitry; and
wherein the processor is operable to process the computer program to determine
the compass directional bearing in response to the location fixes and images captured
by the image capturing circuitry.
9. The device of claim 8 wherein the image capturing circuitry comprises still
image capturing circuitry.
10. The device of claim 8 wherein the image capturing circuitry comprises video
image capturing circuitry.
11. The device of claim 8 wherein the processor is operable to process the computer
program to determine the compass directional bearing in response to either extrapolation
or interpolation of the images.
12. The device of claim 2 wherein the processor comprises a core and a digital
signal processor.
13. The device of claim 2 wherein the means for displaying and means for determining
are part of an electronic device selected from a set consisting of a telephone
and a personal digital assistant.
14. The device of claim 1 wherein the means for displaying and means for determining
are part of an electronic device selected from a set consisting of a telephone
and a personal digital assistant.
15. The device of claim 1 wherein the means for displaying comprises means for
displaying the compass directional bearing on a depiction of a map.
16. The device of claim 1 wherein the image capturing circuitry comprises still
image capturing circuitry.
17. The device of claim 1 wherein the image capturing circuitry comprises video
image capturing circuitry.
18. An electronic device, comprising:
a computer program; and
a processor operable to process the computer program at least in part to determine
a compass directional bearing at least in part in response to image data and unresponsive
to a local magnetic field in which the electronic device is located.
19. The device of claim 18 and further comprising SPS circuitry for determining
location fixes of the electronic device, wherein the processor is operable to process
the computer program to determine the compass directional bearing in response to
the location fixes.
20. The device of claim 18 and further comprising image capturing circuitry for
providing the image data, wherein the processor is operable to process the computer
program to determine the compass directional bearing in response to images captured
by the image capturing circuitry.
21. The device of claim 18 wherein the image capturing circuitry is selected
from a set consisting of still image capturing circuitry and video image capturing circuitry.
22. The device of claim 21 wherein the processor is operable to process the computer
program to determine the compass directional bearing in response to either extrapolation
or interpolation of the images.
23. The device of claim 18 and further comprising:
SPS circuitry for determining location fixes of the electronic device; and
image capturing circuitry; and
wherein the processor is operable to process the computer program to determine
the compass directional bearing in response to the location fixes and images captured
by the image capturing circuitry.
24. The device of claim 23 wherein the image capturing circuitry is selected
from a set consisting of still image capturing circuitry and video image capturing circuitry.
25. The device of claim 23 wherein the processor is operable to process the computer
program to determine the compass directional bearing in response to either extrapolation
or interpolation of the images.
26. The device of claim 18 wherein the processor comprises a core and a digital
signal processor.
27. The device of claim 18 wherein the means for displaying and means for determining
are part of an electronic device selected from a set consisting of a telephone
and a personal digital assistant.
28. The device of claim 18 wherein the image capturing circuitry is selected
from a set consisting of still image capturing circuitry and video image capturing circuitry.
29. Computer programming for use in an electronic device comprising a processor,
the programming for causing the steps of:
determining a compass directional bearing at least in part in response to image
data and unresponsive to a local magnetic field in which the electronic device
is located; and
displaying the compass directional bearing.
30. The computer programming of claim 29, wherein the electronic device further
comprises SPS circuitry for determining location fixes of the electronic device,
wherein the determining step determines the compass directional bearing in response
to the location fixes.
31. The computer programming of claim 29, wherein the electronic device further
comprises image capturing circuitry, wherein the determining step determines the
compass directional bearing in response to the image data as captured by the image
capturing circuitry.
32. The computer programming of claim 31 wherein the image capturing circuitry
comprises still image capturing circuitry.
33. The computer programming of claim 31 wherein the image capturing circuitry
comprises video image capturing circuitry.
34. The computer programming of claim 29, wherein the electronic device further
comprises SPS circuitry for determining location fixes of the electronic device
and image capturing circuitry, wherein the determining step determines the compass
directional bearing in response to the location fixes and images captured by the
image capturing circuitry.
35. The computer programming of claim 34 wherein the image capturing circuitry
is selected from a set consisting of still image capturing circuitry and video
image capturing circuitry.
36. The computer programming of claim 29 wherein the displaying step displays
the compass directional bearing on a depiction of a map.
Description
CROSS-REFERENCES TO RELATED APPLICATION
Not Applicable.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1
a illustrates a front view of an example of a wireless telephone
handset 10 into which a preferred embodiment is implemented.
FIG. 1
b illustrates a rear view of the wireless telephone handset 10
of FIG. 1
a.
FIG. 2 illustrates an electrical block diagram of various functional features
of handset 10.
FIG. 3 illustrates a flowchart of a method 100 of operation of handset
10 in connection with providing a compass functionality in the inventive scope.
FIG. 4
a illustrates an example of directional movement of handset 10
between two location fixes.
FIG. 4
b illustrates the example of FIG. 4
a after handset 10
rotates 90 degrees clockwise following its second location fix in FIG. 4
a.
FIG. 4
c illustrates the 90 degree clockwise rotation of handset 10
as occurring at the second location fix and from FIG. 4
a to FIG. 4
b.
FIG. 5 illustrates an example of directional movement of handset 10 along
a curve with numerous location fixes.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described below in connection with a preferred embodiment,
namely as implemented into an electronic device that includes a compass that operates
in response to various features in that electronic device. Thus, such a compass
may be included in a cellular telephone or a personal digital assistant ("PDA"),
by ways of example. Still other electronic devices may implement such aspects as
well, as may be evident to one skilled in the art. Accordingly, it is to be understood
that the following description is provided by way of example only and is not intended
to limit the inventive scope.
FIG. 1
a illustrates a front view of an example of a wireless telephone
handset
10 into which the preferred embodiments are implemented. Handset
10 includes an antenna ANT for bi-directional communications in the sense
of a cellular or wireless device. However, only received signals are necessary
for purposes of a compass function that is associated with the preferred embodiments
and, thus, the preferred embodiments also may be implemented in connection with
a device that is only operable to receive certain signals, described later, rather
than to bi-directionally communicate signals such as in the case of a cellular
telephone. In the example of FIGS. 1
a (and
1b), handset
10
provides the conventional human interface features, including a microphone MIC,
a speaker SPK, a visual display
12, and a keypad
14. Keypad
14
includes the usual keys for a wireless telephone handset, including numeric keys
0 through 9, the * and # keys, and other keys as in conventional wireless telephone
handsets. In addition and for reasons more clear below, keypad
14 is shown
to include a dedicated COMPASS key
16. According to the preferred embodiments
of the invention, COMPASS key
16 may be pressed to invoke a compass feature
whereby in response to that action and further processing described later, display
12 provides a visual indication of the directional heading of handset
10.
FIG. 1
b illustrates a rear view of wireless telephone handset
10
from FIG. 1
a. This rear perspective is shown to illustrate that handset
10 in the preferred embodiments also includes a camera CAM. As with many
popular contemporary cellular phones, camera CAM is on the rear of handset
10,
although such a location is not necessary. Further, the illustration of camera
CAM in FIG. 1
b is more particularly of its lens for sake of taking pictures
(still or video), as further described later, and one skilled in the art should
appreciate that within handset
10 additional circuitry in this regard is
coupled to that lens as further described below.
Referring now to FIG. 2, the construction of an exemplary electrical block
diagram architecture for handset
10 according to a preferred embodiment
is now described. Of course, the particular architecture of a wireless handset
(or other device within the inventive scope) may vary from that illustrated in
FIG. 2, and as such the architecture of FIG. 2 is presented only by way of example.
As shown in FIG. 2, the functionality of handset
10 is generally controlled
by a processor
18. Processor
18 may take various forms, including
an implementation where it is embodied as a single integrated circuit that includes
both a core and a digital signal processor ("DSP"). High-performance processors
that are suitable for use as such a core include the advanced RISC ("reduced instruction
set computer") machine ("ARM") designed by a company known as ARM Limited. Further,
examples of DSPs suitable for such use include the TMS320c5x family of digital
signal processors available from Texas Instruments Incorporated. In any event,
the functionality of processor
18 preferably includes programmable logic,
such as a microprocessor or microcontroller, that controls the operation of handset
10 according to a computer program or sequence of executable operations
stored in program memory. Preferably, the program memory is on-chip with processor
18, but alternatively it may be implemented in read-only memory ("ROM")
or other storage in a separate integrated circuit. The computational capability
of processor
18 depends on the level of functionality required of handset
10, including the "generation" of wireless services for which handset
10
is to be capable. As known in the art, modern wireless telephone handsets can have
a great deal of functionality, including the capability of Internet web browsing,
email handling, digital still and video photography, global positioning system
("GPS") features, game playing, PDA functionality, and the like, as well as the
additional compass functionality detailed later. The DSP functionality of processor
18 performs the bulk of the digital signal processing for signals to be
transmitted and signals received by handset
10. These functions include
the necessary digital filtering, coding and decoding, digital modulation, and the
like. Lastly, note that DSPs that are comparable in various respects are available
in combined form with the above-discussed core on a single integrated circuit as
a combined processor referred to by Texas Instruments Incorporated as an OMAP,
although in present form they do not include the compass functions detailed later.
Continuing the example of FIG. 2, processor
18 is coupled to visual
display
12 and keypad
14, each for performing well-known functionality.
In addition, and by way of introduction to aspects detailed later, a user may press
COMPASS key
16 (see FIG. 1
a) which is part of keypad
14, and
that action invokes a control signal to processor
18 so that it may process
various signals so as to provide a compass directional indicator on display
12.
Continuing with other functions of FIG. 2. Processor
18 also is coupled
to a power management function
20. Power management function
20 distributes
regulated power supply voltages to various circuitry within handset
10 and
manages functions related to charging and maintenance of the battery (not shown)
of handset
10, including standby and power-down modes to conserve battery
power. Handset
10 also includes radio frequency ("RF") circuitry
22,
which is coupled to antenna ANT and to an analog baseband circuitry
24.
RF circuitry
22 consumes power under control of power management function
20, and it includes such functions as necessary to transmit and receive
the RF signals at the specified frequencies to and from the wireless telephone
communications network that communicates with handset
10. Thus, RF circuitry
22 is contemplated to include such functions as modulation circuitry and
RF input and output drivers. By applying the necessary filtering, coding and decoding,
and the like, analog baseband circuitry
24 processes the signals to be transmitted
(as received from microphone MIC) prior to modulation and the received signals
(to be output over speaker SPK) after demodulation (hence in the baseband). Lastly,
typical functions included within analog baseband circuitry
24 include an
RF coder/decoder ("CODEC"), a voice CODEC, speaker amplifiers, and the like, as
known in the art.
Handset
10 also includes a GPS module
26, which also consumes
power under control of power management function
20 and is coupled to receive
signals from RF circuitry
22 and to function generally according to the
art to process those signals in connection with processor
18. Note that
GPS is only used here by way of example, when in fact GPS is one example of a broader
category of the satellite positioning system ("SPS"). Prior to its use in cellular
phones, SPS has existed for decades and has been used in military and civil applications.
The current SPS system includes the well-known US-owned global positioning satellite
("GPS") system or NAVSTAR and the Russia-owned Global Navigation Satellite System
("GLONASS"). Additionally, the European Union has started its effort to support
SPS with an initiative to position a constellation of satellites, called the Galileo
system, for completion in the future. In any event, many cellular phones are now
including an SPS functionality, and for purposes of the preferred embodiments this
functionality is shown by way of example as GPS, while it should be understood
that the preferred embodiments may be implemented in connection with any SPS technique.
In any event, and as detailed later, the GPS information provided in this manner
also may be used in connection with a novel compass functionality. Looking presently
to the GPS function in general, note that GPS features are now included in various
cellular telephones to process GPS signals from a receiver, such as from the combination
of antenna ANT and RF circuitry
22 or, alternatively, GPS module
26
may include its own RF circuitry, in which case module
26 may receive signals
directly from antenna ANT, with such an alternative connection also being shown
in FIG. 2. In either event, module
26 receives unidirectional communications
from the satellite GPS system which, as known in the GPS art, is a constellation
of a number of satellites that orbit the earth at a given angle relative to the
equator. Each satellite transmits coded position and timing information in a low
power signal and, in response, that information may be received by any GPS-enabled
device, including handset
10. In the case of the latter, those signals are
received by antenna ANT, converted by RF circuitry
22 and processed by GPS
module
26, either alone or in combination with the capabilities of processor
18. Thus, one or the combination of these functional blocks preferably has
a measurement engine and position engine from which a determination of a so-called
location fix of handset
10 is determined, that is, the geographic coordinate
position of handset
10. The accuracy of the location fix depends on various
considerations, but even in a consumer-level device that accuracy may be on the
order of one to two meters. Further, GPS location fix determinations may be improved
in accuracy with supplementation from other GPS services, as known in the art.
In any event, with the GPS location fix of the cellular phone, the phone may use
that information for various applications. In one example, a contemporary standard
requires that a phone such as handset
10 be operable to report its location
in the event that its user calls the emergency 9-1-1 service and, thus, the GPS
functionality of the phone supports this requirement. In another example, the GPS
information may be used in connection with a mapping program associated with the
phone (or other electronic device), so as to depict on display
12 the location
of the phone (and its user) on a displayed map. As detailed below, however, this
information is also used in part to support a novel compass functionality, that
is, to provide a directional heading indication of handset
10.
FIG. 3 illustrates a flowchart of a method
100 of operation of handset
10 in connection with providing a compass functionality in the inventive
scope. By way of introduction, note that the use of a flowchart is merely to explain
various functional concepts and steps, where the order of these steps may be adjusted
and where they may be represented in an alternative fashion, such as in a state
diagram. Moreover, the steps of FIG. 3 are only directed to certain aspects pertaining
to the management of the compass functionality, while one skilled in the art will
readily appreciate that various other functions may occur with respect to handset
10, either simultaneously or in addition to those set forth in FIG. 3. Note
also that the compass functionality of method
100 may be achieved by including
additional computer programming software in connection with processor
18
(e.g., in local or remote memory or other computer-readable medium), where that
software operates with respect to data provided by already-existing hardware including
GPS module
26 and camera CAM, but without reference to any magnetic-sensitive
device as in the prior art. These aspects will be appreciated below, as will be
manners of implementing such software by one skilled in the art.
Turning to method
100 of FIG. 3, it commences with a step
110,
where the compass feature is enabled. In a preferred embodiment, the user of handset
10 may accomplish this task by pressing COMPASS key
16 (FIG. 1
a).
In an alternative embodiment, the compass selection may be programmed into another
general purpose or programmable key or otherwise invoked by operating handset
10
in some desired manner, including navigating to a menu, interface, or the like
on display
12. In any event, once the feature is enabled, method
100
continues from step
110 to step
120.
In step
120, GPS module
26 determines a first location fix LF
x,
that is, from signals received from RF circuitry
22 and with known GPS functionality,
a first set of GPS geographic coordinates are determined for handset
10.
Note that such functionality may be selected from various alternatives and, moreover,
the rate at which first location fix LF
x is determinable may depend
on the supporting GPS methodology. For example, so-called assisted GPS now exists
and may be incorporated into handset
10 so as to reduce the time needed
to determine a first location fix. To further demonstrate step
120 and later
steps, FIGS. 4
a through
4c provide simplified top views of
the positioning of handset
10 in different locations. Moreover, handset
10 is shown in those Figures in general form, with an outline of the handset
and with camera CAM on its underside (as shown in FIGS. 4
a through
4c
with a dashed outline), facing generally downward toward the ground. Further
in this regard and as appreciated with the remaining discussion, in the preferred
embodiments a user of handset
10 is generally encouraged to position handset
10 in this manner while performing method
100, that is, in a horizontal
manner, parallel to the ground and with camera CAM facing downward. As also appreciated
later, however, modest deviations in the horizontal positioning of handset
10
will not interfere with its compass functionality. In any event, FIG. 4
a illustrates
handset
10 wherein the user (not shown) is pointing handset
10 with
a bearing of east, and location fix LF
x is determined from step
110
at that location. Thereafter, method
100 continues from step
120
to step
130.
In step
130, processor
18 enables camera CAM to begin to capture
successive images in time. In a preferred embodiment, these successive images are
captured as an ongoing video stream commencing with step
130. However, in
an alternative embodiment, successive still images may be captured. Either approach
may be achieved using many of various known or developed image techniques, such
as through mpeg, jpeg, or other technologies as ascertainable by one skilled in
the art. Looking again to FIG. 4
a, therefore, image capture occurs at location
fix LF
x and continues as handset
10 is moved eastward. While
image capture continues, method
100 continues from step
130 to step
140.
In step
140, GPS module
26 determines a second location fix LF
x+1,
where the subscript is intended to denote that it follows the first location fix,
LF
x, determined in step
120. Again, the same GPS functionality
used to achieve step
120 is preferably used to achieve step
140.
Thus, in FIG. 4
a, step
140 occurs as shown to the right of the Figure,
which depicts handset
10 at second location fix LF
x+1. Next,
method
100 continues from step
140 to step
150.
In step
150, processor
18 determines the directional bearing (i.e.,
direction of movement) of handset
10 based on the difference of second location
fix LF
x+1 and first location fix LF
x. In other words, these
two points necessarily define a line and, thus, with a geographical coordinate
for each, the directional bearing along that line may be determined. In the example
of FIG. 4
a, therefore, this direction is determined to be east, that is,
handset
10 has been shown in that Figure to have been moved east, as will
be confirmed by calculating the directional difference between LF
x+1 and
LF
x. Note also in this regard that calculating direction based on different
GPS fixes is known in the automotive art, where systems are now available that
perform this function, although they do so with expectations about the fixed orientation
of the receiver relative to the remainder of the vehicle (and the ground) as well
as an anticipation of the vehicle traveling at speeds greater than that which would
be expected from a human traveling without vehicle assistance and carrying a portable
device such as handset
10. In any event, after step
150, method
100
continues from step
150 to step
160.
Step
160 is illustrated in connection with FIG. 4
b. Turning first
then to FIG. 4
b, it is intended to demonstrate the two location fixes of
FIG. 4
a, but now it is shown that the user of handset
10 has rotated
handset
10 by an amount of 90 degrees clockwise, where such movement is
also shown by way of demonstration in FIG. 4
c. Particularly, FIG. 4
c
illustrates handset
10 in a position
104a, which is
intended to illustrate the orientation of handset
10 at the end of its eastward
movement in FIG. 4
a, followed by a 90 degree clockwise rotation to a position
104b, which is intended to illustrate the orientation of handset
10 after both its eastward movement in FIG. 4
a and its 90 degree
clockwise rotation shown in FIG. 4
b. Thus, returning to FIG. 4
b,
it may be appreciated that while handset
10 previously moved east as was
determined by step
150, the directional bearing of handset
10 is
now south, given the 90 degree clockwise rotation. Returning then to FIG. 3 and
step
160, it determines a difference in bearing, if any, from any angular
change in images that have been or are being captured by camera CAM. In other words,
assuming an image IM
T captured at a time T, then step
160 evaluates
that image based on a range R of other images, which may be before and/or after
image IM
T is captured; hence, step
160 is shown to make its determination
relative to images IM
T+IM
R. For example, assume that a number
N of images are captured between the time handset
10 is positioned as shown
at location fix LF
x+1 in FIG. 4
a and as shown at location LF
x+1
in FIG. 4
b, that is, assume N images are captured through the range
of the 90 degree rotation of handset
10. In this or other cases, then in
step
160, various image processing techniques, including by ways of example
extrapolation and interpolation techniques used in mpeg (or the like) video processing,
are employed to determine from those N images the direction and extent of the angular
rotation of handset
10, thereby providing a corresponding determination
of the change in directional bearing of handset
10. Indeed, note that this
image processing also may account for modest variations in the horizontal orientation
of handset
10, that is, if the user while carrying handset
10 departs
from the intended preference of holding it in a horizontal manner, then sufficient
image capture and processing may well be able to account for such deviations, while
still providing a determination of the change, if any, in directional orientation
of handset
10. Next, method
100 continues from step
160 to
step
170.
In step
170, processor
18 modifies the directional bearing from
step
150 with the difference in bearing, if any, based on the captured images.
The result is provided to user
10, such as through display
12 or
through some other means of depicting direction to that user. Thus, returning once
more to FIG. 4
a, step
150 will have determined a directional bearing
of east. However, the subsequent step
160 will have determined a 90 degree
clockwise rotation of handset
10, which is used in step
170 to modify
the step
150 directional bearing, thereby changing it from an east bearing
to a south bearing. The result of south, therefore, is presented to the user of
handset
10 via display
12. The presentation may take various forms.
In one embodiment, the presentation may be an indication of directional bearing
by a letter or arrow or depicted on a screen displayed compass or directional arrow.
In another embodiment, the presentation may locate a directional indicator on a
map that shown the geographic location in which handset
10 is located.
The preceding illustrates that method
100, as shown in the example of
FIGS. 4
a through
4c, permits handset
10 to determine
a directional bearing in response to location fixes and successive image data,
all provided by circuitry and software within handset
10. Note various additional
benefits of these preferred embodiments. First, the example of FIGS. 4
a through
4c is only one of many instances in which method
100 may operate.
Indeed, note that the timing between successive location fixes and the image capture
may be shortened or lengthened so as to adjust accuracy as well as directional
bearing updates. For example, FIG. 5 illustrates another example of directional
movement of handset
10, handset
10 is shown traversing along a curve
that in different instances corresponds to various different directional bearings.
In that example, a total of seven location fixes are taken. Thus, as between each
successive location fix, a straight line might indicate the previous general direction
of movement of handset
10, but because of the curvature of the route the
then-existing actual bearing (or orientation) of handset
10 may differ to
due its rotation of the actual physical device as it travels along the curve. However,
with sufficient image capture this additional rotation may be ascertained as explained
above in connection with step
160 and the directional bearing may be modified
in the corresponding step
170. Thus, many other instances and examples should
be appreciated by one skilled in the art, as should the notion that method
100
may be continuously repeated, with or without requiring a repetition of user-input
such as through step
110, whereby handset
10 continuously updates
its directional bearing by using successive or incremental location fixes as well
as captured image data.
From the above, it may be appreciated that the preferred embodiments provide
a compass for use in an electronic device. Because the compass of the preferred
embodiments determines directional bearing based on GPS and image data, it is operable
irrespective of the magnetic field in which handset
10 is located. In other
words, the compass functionality is unresponsive to the magnetic field that is
influencing the location of handset
10. For this reason, the preferred embodiments
provide various benefits as compared to the prior art. As one example of a benefit,
additional magnetic-responsive devices, which may add cost, complexity, size, and
weight to a portable device are not required in handset
10. As another example
of a benefit, the preferred embodiments provide a compass functionality that is
not susceptible to magnetic field variations that would adversely affect a typical
magnetic-responsive compass. For example, there may be local magnetic attractions
if handset
10 is in the vicinity of something made of iron or a comparably
field influencing substance or device. As another example, there may be localized
aberrations in the earth's magnetic field, and still further there is the possible
influence on magnetic-responsive devices of the different North Poles, that is,
True North and Magnetic North. Nonetheless, the preferred embodiments as shown
above are unresponsive to these localized magnetic effects and, therefore, can
prove meaningful compass functionality in such locations without a disturbance
in the accuracy of the compass. As yet another benefit, many contemporary cellular
telephones already include both GPS and camera functionality and, thus, in these
devices, the preferred embodiments may be implemented by adding purely software
into these devices to program them to operate as described above. Thus, the preferred
embodiments include various aspects and advantages as compared to the prior art,
and still others will be appreciated by one skilled in the art. Moreover, while
the preferred embodiments have been shown by way of example, certain other alternatives
have been provided and still others are contemplated. Thus, the preceding discussion
and these examples should further demonstrate that while the present embodiments
have been described in detail, various substitutions, modifications or alterations
could be made to the descriptions set forth above without departing from the inventive
scope which is defined by the following claims.
*
