1. A method of compressing spectral data corresponding to an image comprising a plurality of pixels, said method comprising:
creating a set of potential endmembers;
identifying a first plurality of said potential endmembers as a first set of endmembers based upon correlation of said first plurality of potential endmembers with a first spectral signature of a first pixel of said plurality of pixels; and
representing said first pixel as a combination of said first set of endmembers, said combination being of a size related to a noise level of said image.
2. The method of claim 1 further including:
identifying a second plurality of said potential endmembers as a second set of endmembers based upon correlation of said second plurality of potential endmembers with a second spectral signature of a second pixel of said plurality of pixels; and
representing said second pixel as a combination of said second set of endmembers.
3. The method of claim 1 wherein said step of identifying includes:
selecting a first of said potential endmembers most closely matching said first spectral signature as a first endmember within said first set of endmembers; and
computing a first residual corresponding to a difference between said first endmember and said first spectral signature.
4. The method of claim 3 wherein said step of identifying further includes:
computing a plurality of residuals corresponding to differences between said first endmember and remaining ones of said set of potential endmembers; and
selecting a second endmember based upon correlation between said first residual and one of said plurality of residuals corresponding to said second endmember.
5. The method of claim 1 wherein said noise level comprises an average noise level, said method further including computing an said average noise level.
6. The method of claim 5 wherein said step of computing an average noise level includes:
computing an average band noise level for each of a plurality of spectral bands inherent in said image; and
converting said average band noise levels to said average noise level.
7. The method of claim 6 further including:
computing an average band signal level for each of said plurality of spectral bands;
computing a signal to noise ratio for each of said plurality of spectral bands based upon the applicable average band signal level and average band noise level; and
removing any of said spectral bands from said image which exhibit a signal to noise ratio less than a predetermined threshold.
8. The method of claim 1 further including computing a residual between said first spectral signature and an approximation of said first spectral signature based upon said first set of endmembers, said residual being less than a predefined value related to noise inherent in said image.
9. A compression system for compressing spectral data corresponding to an image comprising a plurality of pixels, said system comprising:
a database including a set of potential endmembers;
an adaptive linear unmixing module for identifying a first plurality of said potential endmembers as a first set of endmembers based upon correlation of said first plurality of potential endmembers with a first spectral signature of a first pixel of said plurality of pixels; and
an encoder for representing said first pixel as a combination of said first set of endmembers, said combination being of a size related to a noise level of said image.
10. The compression system of claim 9 wherein said adaptive linear unmixing module is disposed to identify a second plurality of said potential endmembers as a second set of endmembers based upon correlation of said second plurality of potential endmembers with a second spectral signature of a second pixel of said plurality of pixels, said encoder representing said second pixel as a combination of said second set of endmembers.
11. The compression system of claim 9 wherein said adaptive linear unmixing module additionally operates to:
select one of said potential endmembers most closely matching said first spectral signature as a first endmember included within said first set of endmembers; and
compute a first residual corresponding to a difference between said first endmember and said first spectral signature.
12. The compression system of claim 11 wherein said adaptive linear unmixing module is further operative to:
compute a plurality of residuals corresponding to differences between said first endmember and remaining ones of said potential endmembers; and
select another one of said potential endmembers as a second endmember based upon correlation between said first residual and one of said plurality of residuals corresponding to said second endmember.
13. The compression system of claim 9 wherein said noise level comprises an average noise level, said system further including an image noise calculation module operative to compute an said average noise level for said image wherein said adaptive linear unmixing module continues to add ones of said potential endmembers to said first set of endmembers until a residual between said first spectral signature and an approximation of said first spectral signature based upon said first set of endmembers becomes less than a predefined target value relating to said average noise level.
14. The compression system of claim 13 wherein said image noise calculation module includes:
means for computing an average band noise level for each of a plurality of spectral bands inherent in said image;
means for computing an average band signal level for each of said plurality of spectral bands;
means for computing a signal to noise ratio for each of said plurality of spectral bands based upon the applicable average band signal level and average band noise level; and
means for removing any of said spectral bands from said image which exhibit a signal to noise ratio less than a predetermined threshold.
15. An article of manufacture, which comprises a computer readable medium having stored therein a computer program carrying out a method of compressing spectral data corresponding to an image comprising a plurality of pixels, the computer program comprising:
(a) a first code segment for creating a set of potential endmembers;
(b) a second code segment for identifying a first plurality of said potential endmembers as a first set of endmembers based upon correlation of said first plurality of potential endmembers with a first spectral signature of a first pixel of said plurality of pixels; and
(c) a third code segment for representing said first pixel as a combination of said first set of endmembers, said combination being of a size related to a noise level of said image.
16. The article of manufacture of claim 15 in which the second code segment identifies a second plurality of said potential endmembers as a second set of endmembers based upon correlation of said second plurality of potential endmembers with a second spectral signature of a second pixel of said plurality of pixels, and in which the third code segment represent said second pixel as a combination of said second set of endmembers.
17. The article of manufacture of claim 15 wherein said noise level comprises an average noise level and in which the computer program includes a fourth code segment for computing an said average noise level for said image and for determining a number of said potential endmembers to be used in representing said first pixel based upon said average noise level.
18. The article of manufacture of claim 17 in which the fourth code segment:
computes an average band noise level for each of a plurality of spectral bands inherent in said image;
computes an average band signal level for each of said plurality of spectral bands;
computes a signal to noise ratio for each of said plurality of spectral bands based upon the applicable average band signal level and average band noise level; and
removes any of said spectral bands from said image which exhibit a signal to noise ratio less than a predetermined threshold.
19. A method for reconstructing an image comprising a plurality of pixels from a compressed data stream, said method comprising the steps of:
extracting a set of endmembers from said data stream wherein said set is of a size related to a noise level of said image;
extracting from said data stream information identifying a first plurality of said endmembers corresponding to a first pixel of said plurality of pixels;
extracting from said data stream a first plurality of endmember coefficients, each of said endmember coefficients corresponding to one of said first plurality of endmembers;
multiplying each of said first plurality of endmembers by a corresponding one of said first plurality of endmember coefficients to produce a first plurality of intermediate products; and
combining said first plurality of intermediate products.
20. The method of claim 19 further including the steps of:
extracting from said data stream information identifying a second plurality of said endmembers corresponding to a second pixel of said plurality of pixels;
extracting from said data stream a second plurality of endmember coefficients, each of said endmember coefficients corresponding to one of said second plurality of endmembers;
multiplying each of said second plurality of endmembers by a corresponding one of said second plurality of endmember coefficients to produce a second plurality of intermediate products; and
combining said second plurality of intermediate products.
21. The method of claim 19 wherein the number of said first plurality of endmembers is based upon an average noise level of said image.
22. An article of manufacture, which comprises a computer readable medium having stored therein a computer program carrying out a method for reconstructing an image comprising a plurality of pixels from a compressed data stream, the computer program comprising:
a first code segment for extracting a set of endmembers from said data stream wherein a size of said set is related to a noise level of said image;
a second code segment for extracting from said data stream information identifying a first plurality of said endmembers corresponding to a first pixel of said plurality of pixels; and
a third code segment for extracting from said data stream a first plurality of endmember coefficients, each of said endmember coefficients corresponding to one of said first plurality of endmembers;
a fourth code segment for multiplying each of said first plurality of endmembers by a corresponding one of said first plurality of endmember coefficients to produce a first plurality of intermediate products; and
a fifth code segment for combining said first plurality of intermediate products.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An apparatus for generating an Electronic Program Guide (EPG), comprising:
a display generation unit configured to output data for generating an EPG, the EPG including:
tiles representing scheduled programs for a plurality of channels, tiles associated with each channel being arranged sequentially along a direction that represents moving forwards in time, a first tile associated with each channel representing a program that has a start time at or before a reference time and an end time after the reference time, wherein at least one start time of a first program on one channel is different from a start time of a first program on at least one other channel, and other tiles associated with that channel representing subsequent programs, and
the EPG further including a highlighted portion which highlights a tile of a first channel; and
a user input receiving unit configured to receive a user input to navigate through the EPG in a forwards or backwards direction in increments of one tile,
wherein, after receiving the user input to navigate in a forwards or backwards direction in increments of one tile through the EPG via the user input receiving unit:
the display generation unit is configured to output data to shift the highlighted portion in a direction in the EPG that corresponds to the user-selected forwards or backwards direction from a rest position to a shifted position;
the display generation unit is configured to output data to scroll the tiles representing programs on the first channel by one tile in an opposite direction to the user-selected forwards or backwards direction, and update the tiles representing programs on the other channels displayed by the EPG based on the reference time being the start time of the program represented by the first tile on the first channel after scrolling; and
the display generation unit is configured to output data to return the highlighted portion back to the rest position after shifting the tiles representing programs on the first channel and updating the tiles representing programs on the other channels.
2. The apparatus according to claim 1, wherein the display generation unit is configured to update the tiles representing programs on channels other than the first channel that are displayed by the EPG by, for each channel other than the first channel, outputting data to either:
(i) scroll each tile representing a program scheduled for a particular channel by an integer number of tiles in the opposite direction to the user-selected forwards or backwards time direction; or
(ii) leave each tile representing a program scheduled for a particular channel stationary.
3. The apparatus according to claim 1, wherein the display generation unit is configured to output data to generate an EPG in which the tiles representing programs are always shown in full regardless of how much of the represented program has elapsed at the reference time, unless the display generation unit is outputting data to scroll tiles representing programs in response to receiving a user input to navigate in a forwards or backwards time direction.
4. The apparatus according to claim 1, wherein the rest position of the highlighted portion corresponds to the position of the tile representing the earliest program on the first channel.
5. The apparatus according to claim 1, wherein the shifted position of the highlighted portion corresponds to the position of the second tile on the first channel before scrolling, when the user input is to navigate in a forwards time direction through the EPG.
6. The apparatus according to claim 1, wherein:
the display generation unit is further configured to output data to include tiles representing said plurality of channels in the EPG; and
the rest position of the highlighted portion corresponds to the position of the tile representing the first channel.
7. The apparatus according to claim 1, wherein:
the display generation unit is further configured to output data to include an icon corresponding to a user input to navigate backwards in time through the EPG; and
the shifted position of the highlighted portion corresponds to the position of said icon when the user input is to navigate in a backwards time direction through the EPG.
8. The apparatus according to claim 1, wherein the distance between the rest position and the shifted position is substantially the same as the distance between centers of neighboring tiles representing programs on a channel.
9. The apparatus according to claim 1, wherein:
the display generation unit is further configured to output data to include tiles representing said plurality of channels in the EPG; and
the rest position of the highlighted portion corresponds to the position of the first tile on the first channel, unless the previous user input was to navigate in a backwards time direction in the EPG, in which case the rest position of the highlighted portion corresponds to the position of the tile representing the first channel.
10. The apparatus according to claim 1, wherein the display generation unit is configured to output data to cause the tiles representing programs to scroll at a time that overlaps with shifting the highlighted portion from the rest position to the shifted position.
11. The apparatus according to claim 1, wherein the display generation unit is configured to output data to cause the tiles representing programs on the first channel to start to scroll substantially at the same time as the highlighted portion starts to be shifted from the rest position to the shifted position.
12. The apparatus according to claim 1, wherein the display generation unit is configured to output data to cause the shift of the highlighted portion from the rest position to the shifted position to be completed at substantially the same time as the tiles representing programs on the first channel have stopped scrolling.
13. The apparatus according to claim 1, wherein the display generation unit is configured to output data to cause the tiles representing programs on the first channel to start to scroll substantially at the same time as the highlighted portion starts to be returned back from the shifted position to the rest position.
14. The apparatus according to claim 1, wherein:
the user input receiving unit is configured to receive an input to display the EPG; and
the display generation unit is configured to output, upon receipt of the input to display the EPG via the user input receiving unit, data to generate an EPG in which the reference time is the current time.
15. The apparatus according to claim 1, further comprising a display device, wherein the display generation unit is configured to output the data to the display device to generate an EPG on the display device.
16. A television set comprising the apparatus according to claim 1.
17. A set-top box comprising the apparatus according to claim 1.
18. A method of generating an Electronic Program Guide (EPG), comprising:
generating an EPG that includes:
tiles representing scheduled programs for a plurality of channels, the tiles associated with each channel being arranged sequentially along a direction that represents moving forwards in time, the first tile associated with each channel representing a program that has a start time at or before a reference time and an end time after the reference time, wherein at least one start time of a first program on one channel is different from a start time of a first program on at least one other channel, and the other tiles associated with that channel representing subsequent programs;
the EPG further includes a highlighted portion for highlighting a tile of a first channel;
receiving a user input to navigate through the EPG in a forwards or backwards direction in increments of one tile; and
upon receipt of said user input:
shifting the highlighted portion in a direction in the EPG that corresponds to the user-selected forwards or backwards direction in increments of one tile from a rest position to a shifted position;
scrolling the tiles representing programs on the first channel along by one tile in the opposite direction to the user-selected forwards or backwards direction, and updating the tiles representing programs on the other channels displayed by the EPG based on the reference time being the start time of the program represented by the first tile on the first channel after scrolling; and
returning the highlighted portion back to the rest position after shifting the tiles representing programs on the first channel and updating the tiles representing programs on the other channels.
19. The method according to claim 18, wherein the step of updating the tiles representing programs on channels other than the first channel that are displayed by the EPG comprises, for each channel other than the first channel, either:
(i) scrolling each tile representing a program scheduled for a particular channel by an integer number of tiles in the opposite direction to the user-selected forwards or backwards time direction; or
(ii) leaving each tile representing a program scheduled for a particular channel stationary.
20. The method according to claim 18, comprising scrolling the tiles at a time that overlaps with shifting the highlighted portion from the rest position to the shifted position.
21. The method according to claim 18, comprising scrolling the tiles at a time that overlaps with returning the highlighted portion from the shifted position to the rest position.
22. The method according to claim 18 further comprising:
displaying the EPG on a display device.
23. A non-transitory computer-readable medium encoded with computer-readable instructions thereon that when executed by a computer cause the computer to perform a method comprising:
generating an Electronic Program Guide (EPG) that includes:
tiles representing scheduled programs for a plurality of channels, the tiles associated with each channel being arranged sequentially along a direction that represents moving forwards in time, the first tile associated with each channel representing a program that has a start time at or before a reference time and an end time after the reference time, wherein at least one start time of a first program on one channel is different from a start time of a first program on at least one other channel, and the other tiles associated with that channel representing subsequent programs;
the EPG further includes a highlighted portion for highlighting a tile of a first channel;
receiving a user input to navigate through the EPG in a forwards or backwards direction in increments of one tile; and
upon receipt of said user input:
shifting the highlighted portion in a direction in the EPG that corresponds to the user-selected forwards or backwards direction in increments of one tile from a rest position to a shifted position;
scrolling the tiles representing programs on the first channel along by one tile in the opposite direction to the user-selected forwards or backwards direction, and updating the tiles representing programs on the other channels displayed by the EPG based on the reference time being the start time of the program represented by the first tile on the first channel after scrolling; and
returning the highlighted portion back to the rest position after shifting the tiles representing programs on the first channel and updating the tiles representing programs on the other channels.