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Digital Camera Patent Abstract
A method of appending a position stamp to an image file of a photo
or video clip taken with a digital camera having a GPS antenna and
a GPS RF front-end including an analogue to digital converter for
receiving GPS signals and outputting GPS signal samples together
with a digital camera and computer for the same. The method comprising
the steps of: (i) upon a user taking a photo or video clip: (a)
creating an image file containing that photo or video clip, and
(b) sampling received GPS signals and storing those GPS signal samples
with an indication of the image file of the photo or video clip
to which those GPS signal samples pertain; and (ii) subsequently
processing the GPS signal samples to obtain a position fix and appending
the position fix to the image file.
Digital Camera Patent Claims
1. A method of appending a position stamp to an image file of a
photo or video clip taken with a digital camera having a GPS antenna
and a GPS RF front-end including an analogue to digital converter
for receiving GPS signals and outputting GPS signal samples, the
method comprising the steps of: (i) upon a user taking a photo or
video clip: (a) creating an image file containing that photo or
video clip, and (b) sampling received GPS signals and storing those
GPS signal samples with an indication of the image file of the photo
or video clip to which those GPS signal samples pertain; and (ii)
subsequently processing the GPS signal samples to obtain a position
fix and appending the position fix to the image file.
2. A method according to claim 1 wherein step (ii) is done after
an intentional delay has elapsed after step (i).
3. A method according to claim 1 further comprising the step of,
after step (i) but before step (ii), uploading the image file and
GPS signal samples to an external computer.
4. A method according to claim 1 further comprising the step of,
after step (i), detecting the connection to the camera of an external
power source whereupon step (ii) is done either automatically or
after user confirmation of an automatic prompt for the same.
5. A method according to claim 1 wherein step (i) is performed
twice upon a user taking respective first and second photo or video
clips, prior to step (ii) being done for the first photo or video
clip.
6. A method according to claim 1 wherein the GPS signal samples
are stored in a file format.
7. A digital camera comprising a GPS antenna and a GPS RF front-end
including an analogue to digital converter for receiving GPS signals
and outputting GPS signal samples; wherein, upon a user taking a
photo or video clip: (a) an image file is created containing that
photo or video clip and (b) received GPS signals are sampled and
the GPS signal samples stored with an indication of the image file
created in step (a) to which those GPS signal samples pertain.
8. A digital camera according to claim 7 further comprising a GPS
signal processor for processing the GPS signal samples to obtain
a position fix and appending the position fix to the image file.
9. A digital camera according to claim 8 configured to process
the GPS signal samples to obtain a position fix after an intentional
delay has elapsed after step (b).
10. A digital camera according to claim 8 configured to process
the GPS signal samples to obtain a position fix after detecting
the connection to the camera of an external power source and either
automatically or after user confirmation of an automatic prompt
for the same.
11. A digital camera according to claim 8 configured to allow steps
(a) and (b) to be performed twice upon a user taking respective
first and second photo or video clips prior to processing the GPS
signal samples to obtain a position fix and appending the position
fix to the image file of the first photo or video clip.
12. A digital camera according to claim 7 configured to upload
the image file and GPS signal samples to an external computer.
13. A digital camera according to claim 12 configured to allow
steps (a) and (b) to be performed twice upon a user taking respective
first and second photo or video clips prior to uploading the image
files and GPS signal samples to an external computer.
14. A digital camera according to claim 7 wherein the GPS signal
samples are stored in a file format.
15. A computer comprising a processor and receiver, and configured
to (a) receive through the receiver an image file containing a photo
or video clip, GPS signal samples and an indication of the corresponding
image file to which the GPS signal samples pertain by virtue of
having been sampled when the corresponding photo or video clip was
taken; (b) process the GPS signal samples to obtain a position fix;
and (c) append the position fix to the corresponding image file.
Digital Camera Patent Description
[0001] This invention relates to a method of appending a position
stamp to an image file of a photo or video clip taken with a digital
camera having a GPS antenna and a GPS RF front-end including an
analogue to digital converter for receiving GPS signals and outputting
GPS signal samples; and to a digital camera and computer for the
same.
[0002] It is known to provide a digital camera having a GPS receiver
wherein image files generated by the digital camera are annotated
or labelled with data identifying the position of the camera at
the time of capture as determined by the GPS receiver. For example,
see U.S. Pat. No. 6,269,446 or European patent application EP1189021A1.
[0003] In accordance with the present invention, there is provided
a method of the aforementioned type comprising the steps of (i)
upon a user taling a photo or video clip: (a) creating an image
file containing that photo or video clip, and (b) sampling received
GPS signals and storing those GPS signal samples, e.g. in a file
format, with an indication of the image file of the photo or video
clip to which those GPS signal samples pertain; and (ii) subsequently
processing the GPS signal samples to obtain a position fix and appending
the position fix to the image file.
[0004] The inventors have realised that storing GPS signal samples
with an indication of the image file of the photo or video clip
to which those GPS signal samples pertain enables those GPS signal
samples to be processed at leisure to determine a position fix and,
thereafter, append a position stamp to the image file. For example,
they may be processed after an intentional delay has elapsed; after
the image file and GPS signal samples have been uploaded to an external
computer; or upon detecting the connection to the camera of an external
power source (either automatically or after user confirmation of
an automatic prompt for the same).
[0005] In particular, step (i) may be performed twice upon a user
taking respective first and second photo or video clips, prior to
step (ii) being done for the first photo or video clip.
[0006] Also provided in accordance with the present invention is
a corresponding digital camera and computer as claimed in claims
7 to 15.
[0007] The present invention will now be described, by way of example
only, with reference to the accompanying figure which shows, schematically,
a PC connected to a digital camera including GPS receiver device,
both operating in accordance with the present invention.
[0008] Referring to the accompanying figure, the PC is connected
via a USB PC port and corresponding cable to a digital camera 10
which comprises a GPS front-end receiver (Rx) connected to a GPS
antenna, an image sensor (IS) and memory (Mem), all under the control
of a micro-controller .mu.C.
[0009] When operative, the GPS receiver receives NAVSTAR SPS GPS
signals through its antenna and pre-process them, typically by passive
bandpass filtering in order to minimise out-of-band RF interference,
preamplification, down conversion to an intermediate frequency (IF)
and analogue to digital conversion. The IF signal remains modulated,
still containing all the information from the available satellites.
The resultant GPS signal samples are then stored in the memory (Mem).
[0010] In accordance with the present invention, the digital camera
and PC may generate a position stamped image file as illustrated
in any of the following example scenarios:
EXAMPLE 1
[0011] Upon a user in possession of the camera taking a photo,
an image file containing that photo is created and stored in the
memory. At the same time, the GPS receiver receives and samples
GPS signals and stores the resultant GPS signal samples in a data
file format in the memory together with an indication of the image
file to which the GPS signal samples pertain.
[0012] Once the user returns home and connects the digital camera
to the user's home PC, the image file and corresponding GPS signal
samples are uploaded to the PC. The GPS signal samples are then
processed using appropriate PC based GPS signal processing software
and the PCs more powerful processor to recover pseudorange information
from which the position of the digital camera when the corresponding
photo was taken can be determined using conventional navigation
algorithms. Such GPS signal acquisition and pseudorange processing
is well known, for example, see GPS Principles and Applications
(Editor, Kaplan) ISBN 0-89006-793-7 Artech House. The position fix
is then appended the image file.
EXAMPLE 2
[0013] As example 1 except that two or more photos are taken with
corresponding image files and GPS signal samples recorded prior
to connection with the PC. Upon connection, both sets of GPS signal
samples are processed and the position fixes obtained appended to
respective image files.
EXAMPLE 3
[0014] Instead of the GPS signal processing software being PC based,
it may be camera based whereby GPS signal samples are processed
only after an intentional delay has elapsed after the image file
has been created and the GPS signal samples stored. For example,
one might post process the GPS signal samples in slow time, thereby
minimising processor power consumption. Similarly, the GPS signal
samples might be processed only after detecting the connection of
the camera to an external power source.
[0015] Whilst the invention has been described in the context of
NAVSTAR GPS, the all weather, spaced based navigation system developed
and currently operated by the US Department of Defense, it will
be appreciated that the invention is equally applicable to other
global positioning systems including GLONASS and Galileo and hybrids
thereof.
[0016] Finally, from a reading of the present disclosure, other
modifications will be apparent to persons skilled in the arts of
GPS and digital cameras which may involve features which are already
known in the design, manufacture and use of GPS receivers, digital
cameras and component parts thereof and which may be used instead
of or in addition to features already described herein.
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